Documentation, tests.

Bumps [golang.org/x/sync](https://github.com/golang/sync) from 0.1.0 to 0.2.0.
- [Commits](https://github.com/golang/sync/compare/v0.1.0...v0.2.0)

---
updated-dependencies:
- dependency-name: golang.org/x/sync
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/go.yml

@@ -5,6 +5,7 @@ on:
     branches: [ "main" ]
   pull_request:
     branches: [ "main" ]
+  workflow_dispatch:
 
 jobs:
   test:
@@ -15,12 +16,30 @@ jobs:
 
     steps:
     - uses: actions/checkout@v3
+      with:
+        lfs: 'true'
 
-    - name: Set up Go
-      uses: actions/setup-go@v3
+    - name: Set up
+      uses: actions/setup-go@v4
       with:
         go-version: stable
-        cache: true
+
+    - name: Format
+      run: gofmt -s -w . && git diff --exit-code
+      if: matrix.os != 'windows-latest'
+
+    - name: Tidy
+      run: go mod tidy && git diff --exit-code
+
+    - name: Download
+      run: go mod download
+
+    - name: Verify
+      run: go mod verify
+
+    - name: Vet
+      run: go vet ./...
+      continue-on-error: true
 
     - name: Build
       run: go build -v ./...
@@ -28,12 +47,15 @@ jobs:
     - name: Test
       run: go test -v ./...
 
-    - name: Test data races
-      run: go test -v -race ./...
-      if: matrix.os == 'ubuntu-latest'
+    - name: Test BSD locks
+      run: go test -v -tags sqlite3_bsd ./...
+      if: matrix.os == 'macos-latest'
 
-    - name: Update coverage report
-      uses: ncruces/go-coverage-report@main
+    - name: Coverage report
+      uses: ncruces/go-coverage-report@v0
+      with:
+        chart: 'true'
+        amend: 'true'
       if: |
         matrix.os == 'ubuntu-latest' &&
         github.event_name == 'push'

.gitignore

@@ -13,7 +13,4 @@
 
 # Dependency directories (remove the comment below to include it)
 # vendor/
-tools
-
-# Project
-sqlite3/sqlite3*
+tools

README.md

@@ -2,7 +2,7 @@
 
 [![Go Reference](https://pkg.go.dev/badge/image)](https://pkg.go.dev/github.com/ncruces/go-sqlite3)
 [![Go Report](https://goreportcard.com/badge/github.com/ncruces/go-sqlite3)](https://goreportcard.com/report/github.com/ncruces/go-sqlite3)
-[![Go Coverage](https://github.com/ncruces/go-sqlite3/wiki/coverage.svg)](https://raw.githack.com/wiki/ncruces/go-sqlite3/coverage.html)
+[![Go Coverage](https://github.com/ncruces/go-sqlite3/wiki/coverage.svg)](https://github.com/ncruces/go-sqlite3/wiki/Test-coverage-report)
 
 Go module `github.com/ncruces/go-sqlite3` wraps a [WASM](https://webassembly.org/) build of [SQLite](https://sqlite.org/),
 and uses [wazero](https://wazero.io/) to provide `cgo`-free SQLite bindings.
@@ -15,9 +15,15 @@ provides a [`database/sql`](https://pkg.go.dev/database/sql) driver
 ([example usage](https://pkg.go.dev/github.com/ncruces/go-sqlite3/driver#example-package)).
 - Package [`github.com/ncruces/go-sqlite3/embed`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/embed)
 embeds a build of SQLite into your application.
+- Package [`github.com/ncruces/go-sqlite3/sqlite3vfs`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/sqlite3vfs)
+wraps the [C SQLite VFS API](https://www.sqlite.org/vfs.html) and provides a pure Go implementation.
 
 ### Caveats
 
+This module replaces the SQLite [OS Interface](https://www.sqlite.org/vfs.html) (aka VFS)
+with a [pure Go](sqlite3vfs/) implementation.
+This has numerous benefits, but also comes with some drawbacks.
+
 #### Write-Ahead Logging
 
 Because WASM does not support shared memory,
@@ -30,44 +36,47 @@ For non-WAL databases, `NORMAL` locking mode can be activated with
 [`PRAGMA locking_mode=NORMAL`](https://www.sqlite.org/pragma.html#pragma_locking_mode).
 
 Because connection pooling is incompatible with `EXCLUSIVE` locking mode,
-the `database/sql` driver defaults to `NORMAL` locking mode,
-and WAL databases are not supported.
+the `database/sql` driver defaults to `NORMAL` locking mode.
+To open WAL databases, or use `EXCLUSIVE` locking mode,
+disable connection pooling by calling
+[`db.SetMaxOpenConns(1)`](https://pkg.go.dev/database/sql#DB.SetMaxOpenConns).
 
-#### Open File Description Locks
+#### POSIX Advisory Locks
 
-On Unix, this module uses [OFD locks](https://www.gnu.org/software/libc/manual/html_node/Open-File-Description-Locks.html)
+POSIX advisory locks, which SQLite uses, are
+[broken by design](https://www.sqlite.org/src/artifact/90c4fa?ln=1073-1161).
+
+On Linux, macOS and illumos, this module uses
+[OFD locks](https://www.gnu.org/software/libc/manual/html_node/Open-File-Description-Locks.html)
 to synchronize access to database files.
+OFD locks are fully compatible with process-associated POSIX advisory locks.
 
-POSIX advisory locks, which SQLite uses, are [broken by design](https://www.sqlite.org/src/artifact/90c4fa?ln=1073-1161).
-OFD locks are fully compatible with process-associated POSIX advisory locks,
-and are supported on Linux, macOS and illumos.
-As a work around for other Unixes, you can use [`nolock=1`](https://www.sqlite.org/uri.html).
+On BSD Unixes, this module uses
+[BSD locks](https://man.freebsd.org/cgi/man.cgi?query=flock&sektion=2).
+BSD locks may _not_ be compatible with process-associated POSIX advisory locks.
+
+#### Testing
+
+The pure Go VFS is stress tested by running an unmodified build of SQLite's
+[mptest](https://github.com/sqlite/sqlite/blob/master/mptest/mptest.c)
+on Linux, macOS and Windows.
+Performance is tested by running
+[speedtest1](https://github.com/sqlite/sqlite/blob/master/test/speedtest1.c).
 
 ### Roadmap
 
-- [x] build SQLite using `zig cc --target=wasm32-wasi`
-- [x] `:memory:` databases
-- [x] port [`test_demovfs.c`](https://www.sqlite.org/src/doc/trunk/src/test_demovfs.c) to Go
-  - branch [`wasi`](https://github.com/ncruces/go-sqlite3/tree/wasi) uses `test_demovfs.c` directly
-- [x] design a nice API, enough for simple use cases
-- [x] provide a simple `database/sql` driver
-- [x] file locking, compatible with SQLite on macOS/Linux/Windows
 - [ ] advanced SQLite features
   - [x] nested transactions
   - [x] incremental BLOB I/O
-  - [ ] online backup
-  - [ ] snapshots
+  - [x] online backup
   - [ ] session extension
-  - [ ] resumable bulk update
-  - [ ] shared cache mode
-  - [ ] unlock-notify
 - [ ] custom SQL functions
 - [ ] custom VFSes
+  - [ ] in-memory VFS
   - [ ] read-only VFS, wrapping an [`io.ReaderAt`](https://pkg.go.dev/io#ReaderAt)
-  - [ ] in-memory VFS, wrapping a [`bytes.Buffer`](https://pkg.go.dev/bytes#Buffer)
   - [ ] cloud-based VFS, based on [Cloud Backed SQLite](https://sqlite.org/cloudsqlite/doc/trunk/www/index.wiki)
-  - [ ] custom VFS API
-  
+  - [x] custom VFS API
+
 ### Alternatives
 
 - [`modernc.org/sqlite`](https://pkg.go.dev/modernc.org/sqlite)

api.go

@@ -1,126 +0,0 @@
-// Package sqlite3 wraps the C SQLite API.
-package sqlite3
-
-import (
-	"context"
-
-	"github.com/tetratelabs/wazero/api"
-)
-
-func newConn(ctx context.Context, module api.Module) (_ *Conn, err error) {
-	getFun := func(name string) api.Function {
-		f := module.ExportedFunction(name)
-		if f == nil {
-			err = noFuncErr + errorString(name)
-			return nil
-		}
-		return f
-	}
-
-	getVal := func(name string) uint32 {
-		global := module.ExportedGlobal(name)
-		if global == nil {
-			err = noGlobalErr + errorString(name)
-			return 0
-		}
-		return memory{module}.readUint32(uint32(global.Get()))
-	}
-
-	c := Conn{
-		ctx: ctx,
-		mem: memory{module},
-		api: sqliteAPI{
-			free:          getFun("free"),
-			malloc:        getFun("malloc"),
-			destructor:    uint64(getVal("malloc_destructor")),
-			errcode:       getFun("sqlite3_errcode"),
-			errstr:        getFun("sqlite3_errstr"),
-			errmsg:        getFun("sqlite3_errmsg"),
-			erroff:        getFun("sqlite3_error_offset"),
-			open:          getFun("sqlite3_open_v2"),
-			close:         getFun("sqlite3_close"),
-			prepare:       getFun("sqlite3_prepare_v3"),
-			finalize:      getFun("sqlite3_finalize"),
-			reset:         getFun("sqlite3_reset"),
-			step:          getFun("sqlite3_step"),
-			exec:          getFun("sqlite3_exec"),
-			clearBindings: getFun("sqlite3_clear_bindings"),
-			bindCount:     getFun("sqlite3_bind_parameter_count"),
-			bindIndex:     getFun("sqlite3_bind_parameter_index"),
-			bindName:      getFun("sqlite3_bind_parameter_name"),
-			bindNull:      getFun("sqlite3_bind_null"),
-			bindInteger:   getFun("sqlite3_bind_int64"),
-			bindFloat:     getFun("sqlite3_bind_double"),
-			bindText:      getFun("sqlite3_bind_text64"),
-			bindBlob:      getFun("sqlite3_bind_blob64"),
-			bindZeroBlob:  getFun("sqlite3_bind_zeroblob64"),
-			columnCount:   getFun("sqlite3_column_count"),
-			columnName:    getFun("sqlite3_column_name"),
-			columnType:    getFun("sqlite3_column_type"),
-			columnInteger: getFun("sqlite3_column_int64"),
-			columnFloat:   getFun("sqlite3_column_double"),
-			columnText:    getFun("sqlite3_column_text"),
-			columnBlob:    getFun("sqlite3_column_blob"),
-			columnBytes:   getFun("sqlite3_column_bytes"),
-			autocommit:    getFun("sqlite3_get_autocommit"),
-			lastRowid:     getFun("sqlite3_last_insert_rowid"),
-			changes:       getFun("sqlite3_changes64"),
-			blobOpen:      getFun("sqlite3_blob_open"),
-			blobClose:     getFun("sqlite3_blob_close"),
-			blobReopen:    getFun("sqlite3_blob_reopen"),
-			blobBytes:     getFun("sqlite3_blob_bytes"),
-			blobRead:      getFun("sqlite3_blob_read"),
-			blobWrite:     getFun("sqlite3_blob_write"),
-			interrupt:     getVal("sqlite3_interrupt_offset"),
-		},
-	}
-	if err != nil {
-		return nil, err
-	}
-	return &c, nil
-}
-
-type sqliteAPI struct {
-	free          api.Function
-	malloc        api.Function
-	destructor    uint64
-	errcode       api.Function
-	errstr        api.Function
-	errmsg        api.Function
-	erroff        api.Function
-	open          api.Function
-	close         api.Function
-	prepare       api.Function
-	finalize      api.Function
-	reset         api.Function
-	step          api.Function
-	exec          api.Function
-	clearBindings api.Function
-	bindNull      api.Function
-	bindCount     api.Function
-	bindIndex     api.Function
-	bindName      api.Function
-	bindInteger   api.Function
-	bindFloat     api.Function
-	bindText      api.Function
-	bindBlob      api.Function
-	bindZeroBlob  api.Function
-	columnCount   api.Function
-	columnName    api.Function
-	columnType    api.Function
-	columnInteger api.Function
-	columnFloat   api.Function
-	columnText    api.Function
-	columnBlob    api.Function
-	columnBytes   api.Function
-	autocommit    api.Function
-	lastRowid     api.Function
-	changes       api.Function
-	blobOpen      api.Function
-	blobClose     api.Function
-	blobReopen    api.Function
-	blobBytes     api.Function
-	blobRead      api.Function
-	blobWrite     api.Function
-	interrupt     uint32
-}

backup.go

@@ -0,0 +1,134 @@
+package sqlite3
+
+// Backup is an handle to an ongoing online backup operation.
+//
+// https://www.sqlite.org/c3ref/backup.html
+type Backup struct {
+	c      *Conn
+	handle uint32
+	otherc uint32
+}
+
+// Backup backs up srcDB on the src connection to the "main" database in dstURI.
+//
+// Backup opens the SQLite database file dstURI,
+// and blocks until the entire backup is complete.
+// Use [Conn.BackupInit] for incremental backup.
+//
+// https://www.sqlite.org/backup.html
+func (src *Conn) Backup(srcDB, dstURI string) error {
+	b, err := src.BackupInit(srcDB, dstURI)
+	if err != nil {
+		return err
+	}
+	defer b.Close()
+	_, err = b.Step(-1)
+	return err
+}
+
+// Restore restores dstDB on the dst connection from the "main" database in srcURI.
+//
+// Restore opens the SQLite database file srcURI,
+// and blocks until the entire restore is complete.
+//
+// https://www.sqlite.org/backup.html
+func (dst *Conn) Restore(dstDB, srcURI string) error {
+	src, err := dst.openDB(srcURI, OPEN_READONLY|OPEN_URI)
+	if err != nil {
+		return err
+	}
+	b, err := dst.backupInit(dst.handle, dstDB, src, "main")
+	if err != nil {
+		return err
+	}
+	defer b.Close()
+	_, err = b.Step(-1)
+	return err
+}
+
+// BackupInit initializes a backup operation to copy the content of one database into another.
+//
+// BackupInit opens the SQLite database file dstURI,
+// then initializes a backup that copies the contents of srcDB on the src connection
+// to the "main" database in dstURI.
+//
+// https://www.sqlite.org/c3ref/backup_finish.html#sqlite3backupinit
+func (src *Conn) BackupInit(srcDB, dstURI string) (*Backup, error) {
+	dst, err := src.openDB(dstURI, OPEN_READWRITE|OPEN_CREATE|OPEN_URI)
+	if err != nil {
+		return nil, err
+	}
+	return src.backupInit(dst, "main", src.handle, srcDB)
+}
+
+func (c *Conn) backupInit(dst uint32, dstName string, src uint32, srcName string) (*Backup, error) {
+	defer c.arena.reset()
+	dstPtr := c.arena.string(dstName)
+	srcPtr := c.arena.string(srcName)
+
+	other := dst
+	if c.handle == dst {
+		other = src
+	}
+
+	r := c.call(c.api.backupInit,
+		uint64(dst), uint64(dstPtr),
+		uint64(src), uint64(srcPtr))
+	if r[0] == 0 {
+		defer c.closeDB(other)
+		r = c.call(c.api.errcode, uint64(dst))
+		return nil, c.module.error(r[0], dst)
+	}
+
+	return &Backup{
+		c:      c,
+		otherc: other,
+		handle: uint32(r[0]),
+	}, nil
+}
+
+// Close finishes a backup operation.
+//
+// It is safe to close a nil, zero or closed Backup.
+//
+// https://www.sqlite.org/c3ref/backup_finish.html#sqlite3backupfinish
+func (b *Backup) Close() error {
+	if b == nil || b.handle == 0 {
+		return nil
+	}
+
+	r := b.c.call(b.c.api.backupFinish, uint64(b.handle))
+	b.c.closeDB(b.otherc)
+	b.handle = 0
+	return b.c.error(r[0])
+}
+
+// Step copies up to nPage pages between the source and destination databases.
+// If nPage is negative, all remaining source pages are copied.
+//
+// https://www.sqlite.org/c3ref/backup_finish.html#sqlite3backupstep
+func (b *Backup) Step(nPage int) (done bool, err error) {
+	r := b.c.call(b.c.api.backupStep, uint64(b.handle), uint64(nPage))
+	if r[0] == _DONE {
+		return true, nil
+	}
+	return false, b.c.error(r[0])
+}
+
+// Remaining returns the number of pages still to be backed up
+// at the conclusion of the most recent [Backup.Step].
+//
+// https://www.sqlite.org/c3ref/backup_finish.html#sqlite3backupremaining
+func (b *Backup) Remaining() int {
+	r := b.c.call(b.c.api.backupRemaining, uint64(b.handle))
+	return int(r[0])
+}
+
+// PageCount returns the total number of pages in the source database
+// at the conclusion of the most recent [Backup.Step].
+//
+// https://www.sqlite.org/c3ref/backup_finish.html#sqlite3backuppagecount
+func (b *Backup) PageCount() int {
+	r := b.c.call(b.c.api.backupFinish, uint64(b.handle))
+	return int(r[0])
+}

blob.go

@@ -1,22 +1,26 @@
 package sqlite3
 
-import "io"
+import (
+	"io"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
+)
 
 // ZeroBlob represents a zero-filled, length n BLOB
 // that can be used as an argument to
 // [database/sql.DB.Exec] and similar methods.
 type ZeroBlob int64
 
-// Blob is a handle to an open BLOB.
+// Blob is an handle to an open BLOB.
 //
 // It implements [io.ReadWriteSeeker] for incremental BLOB I/O.
 //
 // https://www.sqlite.org/c3ref/blob.html
 type Blob struct {
 	c      *Conn
-	handle uint32
 	bytes  int64
 	offset int64
+	handle uint32
 }
 
 var _ io.ReadWriteSeeker = &Blob{}
@@ -25,6 +29,7 @@ var _ io.ReadWriteSeeker = &Blob{}
 //
 // https://www.sqlite.org/c3ref/blob_open.html
 func (c *Conn) OpenBlob(db, table, column string, row int64, write bool) (*Blob, error) {
+	c.checkInterrupt()
 	defer c.arena.reset()
 	blobPtr := c.arena.new(ptrlen)
 	dbPtr := c.arena.string(db)
@@ -45,7 +50,7 @@ func (c *Conn) OpenBlob(db, table, column string, row int64, write bool) (*Blob,
 	}
 
 	blob := Blob{c: c}
-	blob.handle = c.mem.readUint32(blobPtr)
+	blob.handle = util.ReadUint32(c.mod, blobPtr)
 	blob.bytes = int64(c.call(c.api.blobBytes, uint64(blob.handle))[0])
 	return &blob, nil
 }
@@ -81,14 +86,14 @@ func (b *Blob) Read(p []byte) (n int, err error) {
 		return 0, io.EOF
 	}
 
-	want := int64(len(p))
 	avail := b.bytes - b.offset
+	want := int64(len(p))
 	if want > avail {
 		want = avail
 	}
 
-	ptr := b.c.new(uint64(want))
-	defer b.c.free(ptr)
+	defer b.c.arena.reset()
+	ptr := b.c.arena.new(uint64(want))
 
 	r := b.c.call(b.c.api.blobRead, uint64(b.handle),
 		uint64(ptr), uint64(want), uint64(b.offset))
@@ -96,30 +101,68 @@ func (b *Blob) Read(p []byte) (n int, err error) {
 	if err != nil {
 		return 0, err
 	}
-
-	mem := b.c.mem.view(ptr, uint64(want))
-	copy(p, mem)
 	b.offset += want
 	if b.offset >= b.bytes {
 		err = io.EOF
 	}
+
+	copy(p, util.View(b.c.mod, ptr, uint64(want)))
 	return int(want), err
 }
 
+// WriteTo implements the [io.WriterTo] interface.
+//
+// https://www.sqlite.org/c3ref/blob_read.html
+func (b *Blob) WriteTo(w io.Writer) (n int64, err error) {
+	if b.offset >= b.bytes {
+		return 0, nil
+	}
+
+	avail := b.bytes - b.offset
+	want := int64(65536)
+	if want > avail {
+		want = avail
+	}
+
+	ptr := b.c.new(uint64(want))
+	defer b.c.free(ptr)
+
+	for want > 0 {
+		r := b.c.call(b.c.api.blobRead, uint64(b.handle),
+			uint64(ptr), uint64(want), uint64(b.offset))
+		err = b.c.error(r[0])
+		if err != nil {
+			return n, err
+		}
+
+		mem := util.View(b.c.mod, ptr, uint64(want))
+		m, err := w.Write(mem[:want])
+		b.offset += int64(m)
+		n += int64(m)
+		if err != nil {
+			return n, err
+		}
+		if int64(m) != want {
+			return n, io.ErrShortWrite
+		}
+
+		avail = b.bytes - b.offset
+		if want > avail {
+			want = avail
+		}
+	}
+	return n, nil
+}
+
 // Write implements the [io.Writer] interface.
 //
 // https://www.sqlite.org/c3ref/blob_write.html
 func (b *Blob) Write(p []byte) (n int, err error) {
-	offset := b.offset
-	if offset > b.bytes {
-		offset = b.bytes
-	}
-
-	ptr := b.c.newBytes(p)
-	defer b.c.free(ptr)
+	defer b.c.arena.reset()
+	ptr := b.c.arena.bytes(p)
 
 	r := b.c.call(b.c.api.blobWrite, uint64(b.handle),
-		uint64(ptr), uint64(len(p)), uint64(offset))
+		uint64(ptr), uint64(len(p)), uint64(b.offset))
 	err = b.c.error(r[0])
 	if err != nil {
 		return 0, err
@@ -128,11 +171,57 @@ func (b *Blob) Write(p []byte) (n int, err error) {
 	return len(p), nil
 }
 
+// ReadFrom implements the [io.ReaderFrom] interface.
+//
+// https://www.sqlite.org/c3ref/blob_write.html
+func (b *Blob) ReadFrom(r io.Reader) (n int64, err error) {
+	avail := b.bytes - b.offset
+	want := int64(65536)
+	if want > avail {
+		want = avail
+	}
+	if want < 1 {
+		want = 1
+	}
+
+	ptr := b.c.new(uint64(want))
+	defer b.c.free(ptr)
+
+	for {
+		mem := util.View(b.c.mod, ptr, uint64(want))
+		m, err := r.Read(mem[:want])
+		if m > 0 {
+			r := b.c.call(b.c.api.blobWrite, uint64(b.handle),
+				uint64(ptr), uint64(m), uint64(b.offset))
+			err := b.c.error(r[0])
+			if err != nil {
+				return n, err
+			}
+			b.offset += int64(m)
+			n += int64(m)
+		}
+		if err == io.EOF {
+			return n, nil
+		}
+		if err != nil {
+			return n, err
+		}
+
+		avail = b.bytes - b.offset
+		if want > avail {
+			want = avail
+		}
+		if want < 1 {
+			want = 1
+		}
+	}
+}
+
 // Seek implements the [io.Seeker] interface.
 func (b *Blob) Seek(offset int64, whence int) (int64, error) {
 	switch whence {
 	default:
-		return 0, whenceErr
+		return 0, util.WhenceErr
 	case io.SeekStart:
 		break
 	case io.SeekCurrent:
@@ -141,7 +230,7 @@ func (b *Blob) Seek(offset int64, whence int) (int64, error) {
 		offset += b.bytes
 	}
 	if offset < 0 {
-		return 0, offsetErr
+		return 0, util.OffsetErr
 	}
 	b.offset = offset
 	return offset, nil
@@ -151,8 +240,8 @@ func (b *Blob) Seek(offset int64, whence int) (int64, error) {
 //
 // https://www.sqlite.org/c3ref/blob_reopen.html
 func (b *Blob) Reopen(row int64) error {
-	r := b.c.call(b.c.api.blobReopen, uint64(b.handle), uint64(row))
+	err := b.c.error(b.c.call(b.c.api.blobReopen, uint64(b.handle), uint64(row))[0])
 	b.bytes = int64(b.c.call(b.c.api.blobBytes, uint64(b.handle))[0])
 	b.offset = 0
-	return b.c.error(r[0])
+	return err
 }

compile.go

@@ -1,68 +0,0 @@
-package sqlite3
-
-import (
-	"context"
-	"crypto/rand"
-	"os"
-	"runtime"
-	"strconv"
-	"sync"
-	"sync/atomic"
-
-	"github.com/tetratelabs/wazero"
-	"github.com/tetratelabs/wazero/api"
-)
-
-// Configure SQLite WASM.
-//
-// Importing package embed initializes these
-// with an appropriate build of SQLite:
-//
-//	import _ "github.com/ncruces/go-sqlite3/embed"
-var (
-	Binary []byte // WASM binary to load.
-	Path   string // Path to load the binary from.
-)
-
-var sqlite3 sqlite3Runtime
-
-type sqlite3Runtime struct {
-	once      sync.Once
-	runtime   wazero.Runtime
-	compiled  wazero.CompiledModule
-	instances atomic.Uint64
-	err       error
-}
-
-func (s *sqlite3Runtime) instantiateModule(ctx context.Context) (api.Module, error) {
-	s.once.Do(func() { s.compileModule(ctx) })
-	if s.err != nil {
-		return nil, s.err
-	}
-
-	cfg := wazero.NewModuleConfig().
-		WithName("sqlite3-" + strconv.FormatUint(s.instances.Add(1), 10)).
-		WithSysWalltime().WithSysNanotime().WithSysNanosleep().
-		WithOsyield(runtime.Gosched).
-		WithRandSource(rand.Reader)
-	return s.runtime.InstantiateModule(ctx, s.compiled, cfg)
-}
-
-func (s *sqlite3Runtime) compileModule(ctx context.Context) {
-	s.runtime = wazero.NewRuntime(ctx)
-	vfsInstantiate(ctx, s.runtime)
-
-	bin := Binary
-	if bin == nil && Path != "" {
-		bin, s.err = os.ReadFile(Path)
-		if s.err != nil {
-			return
-		}
-	}
-	if bin == nil {
-		s.err = binaryErr
-		return
-	}
-
-	s.compiled, s.err = s.runtime.CompileModule(ctx, bin)
-}

conn.go

@@ -3,14 +3,15 @@ package sqlite3
 import (
 	"context"
 	"database/sql/driver"
+	"errors"
 	"fmt"
-	"math"
 	"net/url"
+	"runtime"
 	"strings"
 	"sync/atomic"
 	"unsafe"
 
-	"github.com/tetratelabs/wazero/api"
+	"github.com/ncruces/go-sqlite3/internal/util"
 )
 
 // Conn is a database connection handle.
@@ -18,56 +19,70 @@ import (
 //
 // https://www.sqlite.org/c3ref/sqlite3.html
 type Conn struct {
-	ctx    context.Context
-	api    sqliteAPI
-	mem    memory
-	handle uint32
+	*module
 
-	arena     arena
 	interrupt context.Context
 	waiter    chan struct{}
 	pending   *Stmt
+	arena     arena
+
+	handle uint32
 }
 
-// Open calls [OpenFlags] with [OPEN_READWRITE], [OPEN_CREATE] and [OPEN_URI].
-func Open(filename string) (conn *Conn, err error) {
-	return OpenFlags(filename, OPEN_READWRITE|OPEN_CREATE|OPEN_URI)
+// Open calls [OpenFlags] with [OPEN_READWRITE], [OPEN_CREATE], [OPEN_URI] and [OPEN_NOFOLLOW].
+func Open(filename string) (*Conn, error) {
+	return newConn(filename, OPEN_READWRITE|OPEN_CREATE|OPEN_URI|OPEN_NOFOLLOW)
 }
 
 // OpenFlags opens an SQLite database file as specified by the filename argument.
 //
+// If none of the required flags is used, a combination of [OPEN_READWRITE] and [OPEN_CREATE] is used.
 // If a URI filename is used, PRAGMA statements to execute can be specified using "_pragma":
 //
 //	sqlite3.Open("file:demo.db?_pragma=busy_timeout(10000)&_pragma=locking_mode(normal)")
 //
 // https://www.sqlite.org/c3ref/open.html
-func OpenFlags(filename string, flags OpenFlag) (conn *Conn, err error) {
-	ctx := context.Background()
-	module, err := sqlite3.instantiateModule(ctx)
+func OpenFlags(filename string, flags OpenFlag) (*Conn, error) {
+	if flags&(OPEN_READONLY|OPEN_READWRITE|OPEN_CREATE) == 0 {
+		flags |= OPEN_READWRITE | OPEN_CREATE
+	}
+	return newConn(filename, flags)
+}
+
+func newConn(filename string, flags OpenFlag) (conn *Conn, err error) {
+	mod, err := instantiateModule()
 	if err != nil {
 		return nil, err
 	}
 	defer func() {
 		if conn == nil {
-			module.Close(ctx)
+			mod.close()
+		} else {
+			runtime.SetFinalizer(conn, util.Finalizer[Conn](3))
 		}
 	}()
 
-	c, err := newConn(ctx, module)
+	c := &Conn{module: mod}
+	c.arena = c.newArena(1024)
+	c.handle, err = c.openDB(filename, flags)
 	if err != nil {
 		return nil, err
 	}
-	c.arena = c.newArena(1024)
+	return c, nil
+}
 
+func (c *Conn) openDB(filename string, flags OpenFlag) (uint32, error) {
 	defer c.arena.reset()
 	connPtr := c.arena.new(ptrlen)
 	namePtr := c.arena.string(filename)
 
+	flags |= OPEN_EXRESCODE
 	r := c.call(c.api.open, uint64(namePtr), uint64(connPtr), uint64(flags), 0)
 
-	c.handle = c.mem.readUint32(connPtr)
-	if err := c.error(r[0]); err != nil {
-		return nil, err
+	handle := util.ReadUint32(c.mod, connPtr)
+	if err := c.module.error(r[0], handle); err != nil {
+		c.closeDB(handle)
+		return 0, err
 	}
 
 	if flags|OPEN_URI != 0 && strings.HasPrefix(filename, "file:") {
@@ -80,11 +95,27 @@ func OpenFlags(filename string, flags OpenFlag) (conn *Conn, err error) {
 				pragmas.WriteByte(';')
 			}
 		}
-		if err := c.Exec(pragmas.String()); err != nil {
-			return nil, fmt.Errorf("sqlite3: invalid _pragma: %w", err)
+
+		c.arena.reset()
+		pragmaPtr := c.arena.string(pragmas.String())
+		r := c.call(c.api.exec, uint64(handle), uint64(pragmaPtr), 0, 0, 0)
+		if err := c.module.error(r[0], handle, pragmas.String()); err != nil {
+			if errors.Is(err, ERROR) {
+				err = fmt.Errorf("sqlite3: invalid _pragma: %w", err)
+			}
+			c.closeDB(handle)
+			return 0, err
 		}
 	}
-	return c, nil
+
+	return handle, nil
+}
+
+func (c *Conn) closeDB(handle uint32) {
+	r := c.call(c.api.closeZombie, uint64(handle))
+	if err := c.module.error(r[0], handle); err != nil {
+		panic(err)
+	}
 }
 
 // Close closes the database connection.
@@ -102,6 +133,8 @@ func (c *Conn) Close() error {
 	}
 
 	c.SetInterrupt(context.Background())
+	c.pending.Close()
+	c.pending = nil
 
 	r := c.call(c.api.close, uint64(c.handle))
 	if err := c.error(r[0]); err != nil {
@@ -109,7 +142,8 @@ func (c *Conn) Close() error {
 	}
 
 	c.handle = 0
-	return c.mem.mod.Close(c.ctx)
+	runtime.SetFinalizer(c, nil)
+	return c.module.close()
 }
 
 // Exec is a convenience function that allows an application to run
@@ -125,22 +159,6 @@ func (c *Conn) Exec(sql string) error {
 	return c.error(r[0])
 }
 
-// MustPrepare calls [Conn.Prepare] and panics on error,
-// a nil Stmt, or a non-empty tail.
-func (c *Conn) MustPrepare(sql string) *Stmt {
-	s, tail, err := c.PrepareFlags(sql, 0)
-	if err != nil {
-		panic(err)
-	}
-	if s == nil {
-		panic(emptyErr)
-	}
-	if !emptyStatement(tail) {
-		panic(tailErr)
-	}
-	return s
-}
-
 // Prepare calls [Conn.PrepareFlags] with no flags.
 func (c *Conn) Prepare(sql string) (stmt *Stmt, tail string, err error) {
 	return c.PrepareFlags(sql, 0)
@@ -167,8 +185,8 @@ func (c *Conn) PrepareFlags(sql string, flags PrepareFlag) (stmt *Stmt, tail str
 		uint64(stmtPtr), uint64(tailPtr))
 
 	stmt = &Stmt{c: c}
-	stmt.handle = c.mem.readUint32(stmtPtr)
-	i := c.mem.readUint32(tailPtr)
+	stmt.handle = util.ReadUint32(c.mod, stmtPtr)
+	i := util.ReadUint32(c.mod, tailPtr)
 	tail = sql[i-sqlPtr:]
 
 	if err := c.error(r[0], sql); err != nil {
@@ -228,26 +246,23 @@ func (c *Conn) SetInterrupt(ctx context.Context) (old context.Context) {
 		<-c.waiter             // Wait for it to finish.
 		c.waiter = nil
 	}
+	// Reset the pending statement.
+	if c.pending != nil {
+		c.pending.Reset()
+	}
 
 	old = c.interrupt
 	c.interrupt = ctx
 	if ctx == nil || ctx.Done() == nil {
-		// Finalize the uncompleted SQL statement.
-		if c.pending != nil {
-			c.pending.Close()
-			c.pending = nil
-		}
 		return old
 	}
 
 	// Creating an uncompleted SQL statement prevents SQLite from ignoring
 	// an interrupt that comes before any other statements are started.
 	if c.pending == nil {
-		c.pending = c.MustPrepare(`SELECT 1 UNION ALL SELECT 2`)
-		c.pending.Step()
-	} else {
-		c.pending.Reset()
+		c.pending, _, _ = c.Prepare(`SELECT 1 UNION ALL SELECT 2`)
 	}
+	c.pending.Step()
 
 	// Don't create the goroutine if we're already interrupted.
 	// This happens frequently while restoring to a previously interrupted state.
@@ -263,7 +278,8 @@ func (c *Conn) SetInterrupt(ctx context.Context) (old context.Context) {
 			break
 
 		case <-ctx.Done(): // Done was closed.
-			buf := c.mem.view(c.handle+c.api.interrupt, 4)
+			const isInterruptedOffset = 280
+			buf := util.View(c.mod, c.handle+isInterruptedOffset, 4)
 			(*atomic.Uint32)(unsafe.Pointer(&buf[0])).Store(1)
 			// Wait for the next call to SetInterrupt.
 			<-waiter
@@ -279,7 +295,8 @@ func (c *Conn) checkInterrupt() bool {
 	if c.interrupt == nil || c.interrupt.Err() == nil {
 		return false
 	}
-	buf := c.mem.view(c.handle+c.api.interrupt, 4)
+	const isInterruptedOffset = 280
+	buf := util.View(c.mod, c.handle+isInterruptedOffset, 4)
 	(*atomic.Uint32)(unsafe.Pointer(&buf[0])).Store(1)
 	return true
 }
@@ -287,144 +304,22 @@ func (c *Conn) checkInterrupt() bool {
 // Pragma executes a PRAGMA statement and returns any results.
 //
 // https://www.sqlite.org/pragma.html
-func (c *Conn) Pragma(str string) []string {
-	stmt := c.MustPrepare(`PRAGMA ` + str)
+func (c *Conn) Pragma(str string) ([]string, error) {
+	stmt, _, err := c.Prepare(`PRAGMA ` + str)
+	if err != nil {
+		return nil, err
+	}
 	defer stmt.Close()
 
 	var pragmas []string
 	for stmt.Step() {
 		pragmas = append(pragmas, stmt.ColumnText(0))
 	}
-	return pragmas
+	return pragmas, stmt.Close()
 }
 
 func (c *Conn) error(rc uint64, sql ...string) error {
-	if rc == _OK {
-		return nil
-	}
-
-	err := Error{code: rc}
-
-	if err.Code() == NOMEM || err.ExtendedCode() == IOERR_NOMEM {
-		panic(oomErr)
-	}
-
-	var r []uint64
-
-	r, _ = c.api.errstr.Call(c.ctx, rc)
-	if r != nil {
-		err.str = c.mem.readString(uint32(r[0]), _MAX_STRING)
-	}
-
-	r, _ = c.api.errmsg.Call(c.ctx, uint64(c.handle))
-	if r != nil {
-		err.msg = c.mem.readString(uint32(r[0]), _MAX_STRING)
-	}
-
-	if sql != nil {
-		r, _ = c.api.erroff.Call(c.ctx, uint64(c.handle))
-		if r != nil && r[0] != math.MaxUint32 {
-			err.sql = sql[0][r[0]:]
-		}
-	}
-
-	switch err.msg {
-	case err.str, "not an error":
-		err.msg = ""
-	}
-	return &err
-}
-
-func (c *Conn) call(fn api.Function, params ...uint64) []uint64 {
-	r, err := fn.Call(c.ctx, params...)
-	if err != nil {
-		panic(err)
-	}
-	return r
-}
-
-func (c *Conn) free(ptr uint32) {
-	if ptr == 0 {
-		return
-	}
-	c.call(c.api.free, uint64(ptr))
-}
-
-func (c *Conn) new(size uint64) uint32 {
-	if size > _MAX_ALLOCATION_SIZE {
-		panic(oomErr)
-	}
-	r := c.call(c.api.malloc, size)
-	ptr := uint32(r[0])
-	if ptr == 0 && size != 0 {
-		panic(oomErr)
-	}
-	return ptr
-}
-
-func (c *Conn) newBytes(b []byte) uint32 {
-	if b == nil {
-		return 0
-	}
-	ptr := c.new(uint64(len(b)))
-	c.mem.writeBytes(ptr, b)
-	return ptr
-}
-
-func (c *Conn) newString(s string) uint32 {
-	ptr := c.new(uint64(len(s) + 1))
-	c.mem.writeString(ptr, s)
-	return ptr
-}
-
-func (c *Conn) newArena(size uint64) arena {
-	return arena{
-		c:    c,
-		base: c.new(size),
-		size: uint32(size),
-	}
-}
-
-type arena struct {
-	c    *Conn
-	base uint32
-	next uint32
-	size uint32
-	ptrs []uint32
-}
-
-func (a *arena) free() {
-	if a.c == nil {
-		return
-	}
-	a.reset()
-	a.c.free(a.base)
-	a.c = nil
-}
-
-func (a *arena) reset() {
-	for _, ptr := range a.ptrs {
-		a.c.free(ptr)
-	}
-	a.ptrs = nil
-	a.next = 0
-}
-
-func (a *arena) new(size uint64) uint32 {
-	if size <= uint64(a.size-a.next) {
-		ptr := a.base + a.next
-		a.next += uint32(size)
-		return ptr
-	}
-	ptr := a.c.new(size)
-	a.ptrs = append(a.ptrs, ptr)
-	return ptr
-}
-
-func (a *arena) string(s string) uint32 {
-	ptr := a.new(uint64(len(s) + 1))
-	a.c.mem.writeString(ptr, s)
-	return ptr
+	return c.module.error(rc, c.handle, sql...)
 }
 
 // DriverConn is implemented by the SQLite [database/sql] driver connection.
@@ -439,6 +334,8 @@ type DriverConn interface {
 	driver.ExecerContext
 	driver.ConnPrepareContext
 
-	Savepoint() (release func(*error))
+	Savepoint() Savepoint
 	OpenBlob(db, table, column string, row int64, write bool) (*Blob, error)
+
+	SetInterrupt(ctx context.Context) (old context.Context)
 }

const.go

@@ -9,8 +9,7 @@ const (
 
 	_UTF8 = 1
 
-	_MAX_STRING   = 512 // Used for short strings: names, error messages…
-	_MAX_PATHNAME = 512
+	_MAX_STRING = 512 // Used for short strings: names, error messages…
 
 	_MAX_ALLOCATION_SIZE = 0x7ffffeff
 
@@ -133,46 +132,28 @@ const (
 	CONSTRAINT_DATATYPE     ExtendedErrorCode = xErrorCode(CONSTRAINT) | (12 << 8)
 	NOTICE_RECOVER_WAL      ExtendedErrorCode = xErrorCode(NOTICE) | (1 << 8)
 	NOTICE_RECOVER_ROLLBACK ExtendedErrorCode = xErrorCode(NOTICE) | (2 << 8)
+	NOTICE_RBU              ExtendedErrorCode = xErrorCode(NOTICE) | (3 << 8)
 	WARNING_AUTOINDEX       ExtendedErrorCode = xErrorCode(WARNING) | (1 << 8)
 	AUTH_USER               ExtendedErrorCode = xErrorCode(AUTH) | (1 << 8)
 )
 
-// OpenFlag is a flag for a file open operation.
+// OpenFlag is a flag for the [OpenFlags] function.
 //
 // https://www.sqlite.org/c3ref/c_open_autoproxy.html
 type OpenFlag uint32
 
 const (
-	OPEN_READONLY      OpenFlag = 0x00000001 /* Ok for sqlite3_open_v2() */
-	OPEN_READWRITE     OpenFlag = 0x00000002 /* Ok for sqlite3_open_v2() */
-	OPEN_CREATE        OpenFlag = 0x00000004 /* Ok for sqlite3_open_v2() */
-	OPEN_DELETEONCLOSE OpenFlag = 0x00000008 /* VFS only */
-	OPEN_EXCLUSIVE     OpenFlag = 0x00000010 /* VFS only */
-	OPEN_AUTOPROXY     OpenFlag = 0x00000020 /* VFS only */
-	OPEN_URI           OpenFlag = 0x00000040 /* Ok for sqlite3_open_v2() */
-	OPEN_MEMORY        OpenFlag = 0x00000080 /* Ok for sqlite3_open_v2() */
-	OPEN_MAIN_DB       OpenFlag = 0x00000100 /* VFS only */
-	OPEN_TEMP_DB       OpenFlag = 0x00000200 /* VFS only */
-	OPEN_TRANSIENT_DB  OpenFlag = 0x00000400 /* VFS only */
-	OPEN_MAIN_JOURNAL  OpenFlag = 0x00000800 /* VFS only */
-	OPEN_TEMP_JOURNAL  OpenFlag = 0x00001000 /* VFS only */
-	OPEN_SUBJOURNAL    OpenFlag = 0x00002000 /* VFS only */
-	OPEN_SUPER_JOURNAL OpenFlag = 0x00004000 /* VFS only */
-	OPEN_NOMUTEX       OpenFlag = 0x00008000 /* Ok for sqlite3_open_v2() */
-	OPEN_FULLMUTEX     OpenFlag = 0x00010000 /* Ok for sqlite3_open_v2() */
-	OPEN_SHAREDCACHE   OpenFlag = 0x00020000 /* Ok for sqlite3_open_v2() */
-	OPEN_PRIVATECACHE  OpenFlag = 0x00040000 /* Ok for sqlite3_open_v2() */
-	OPEN_WAL           OpenFlag = 0x00080000 /* VFS only */
-	OPEN_NOFOLLOW      OpenFlag = 0x01000000 /* Ok for sqlite3_open_v2() */
-	OPEN_EXRESCODE     OpenFlag = 0x02000000 /* Extended result codes */
-)
-
-type _AccessFlag uint32
-
-const (
-	_ACCESS_EXISTS    _AccessFlag = 0
-	_ACCESS_READWRITE _AccessFlag = 1 /* Used by PRAGMA temp_store_directory */
-	_ACCESS_READ      _AccessFlag = 2 /* Unused */
+	OPEN_READONLY     OpenFlag = 0x00000001 /* Ok for sqlite3_open_v2() */
+	OPEN_READWRITE    OpenFlag = 0x00000002 /* Ok for sqlite3_open_v2() */
+	OPEN_CREATE       OpenFlag = 0x00000004 /* Ok for sqlite3_open_v2() */
+	OPEN_URI          OpenFlag = 0x00000040 /* Ok for sqlite3_open_v2() */
+	OPEN_MEMORY       OpenFlag = 0x00000080 /* Ok for sqlite3_open_v2() */
+	OPEN_NOMUTEX      OpenFlag = 0x00008000 /* Ok for sqlite3_open_v2() */
+	OPEN_FULLMUTEX    OpenFlag = 0x00010000 /* Ok for sqlite3_open_v2() */
+	OPEN_SHAREDCACHE  OpenFlag = 0x00020000 /* Ok for sqlite3_open_v2() */
+	OPEN_PRIVATECACHE OpenFlag = 0x00040000 /* Ok for sqlite3_open_v2() */
+	OPEN_NOFOLLOW     OpenFlag = 0x01000000 /* Ok for sqlite3_open_v2() */
+	OPEN_EXRESCODE    OpenFlag = 0x02000000 /* Extended result codes */
 )
 
 // PrepareFlag is a flag that can be passed to [Conn.PrepareFlags].

driver/driver.go

@@ -16,7 +16,7 @@
 //
 //	sql.Open("sqlite3", "file:demo.db?_pragma=busy_timeout(10000)&_pragma=locking_mode(normal)")
 //
-// If no PRAGMAs are specifed, a busy timeout of 1 minute
+// If no PRAGMAs are specified, a busy timeout of 1 minute
 // and normal locking mode are used.
 //
 // [URI]: https://www.sqlite.org/uri.html
@@ -35,6 +35,7 @@ import (
 	"time"
 
 	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
 )
 
 func init() {
@@ -44,12 +45,12 @@ func init() {
 type sqlite struct{}
 
 func (sqlite) Open(name string) (_ driver.Conn, err error) {
-	c, err := sqlite3.OpenFlags(name, sqlite3.OPEN_READWRITE|sqlite3.OPEN_CREATE|sqlite3.OPEN_URI|sqlite3.OPEN_EXRESCODE)
+	var c conn
+	c.conn, err = sqlite3.Open(name)
 	if err != nil {
 		return nil, err
 	}
 
-	var txBegin string
 	var pragmas []string
 	if strings.HasPrefix(name, "file:") {
 		if _, after, ok := strings.Cut(name, "?"); ok {
@@ -57,9 +58,9 @@ func (sqlite) Open(name string) (_ driver.Conn, err error) {
 
 			switch s := query.Get("_txlock"); s {
 			case "":
-				txBegin = "BEGIN"
+				c.txBegin = "BEGIN"
 			case "deferred", "immediate", "exclusive":
-				txBegin = "BEGIN " + s
+				c.txBegin = "BEGIN " + s
 			default:
 				c.Close()
 				return nil, fmt.Errorf("sqlite3: invalid _txlock: %s", s)
@@ -69,32 +70,52 @@ func (sqlite) Open(name string) (_ driver.Conn, err error) {
 		}
 	}
 	if len(pragmas) == 0 {
-		err := c.Exec(`
-			PRAGMA busy_timeout=60000;
+		err := c.conn.Exec(`
 			PRAGMA locking_mode=normal;
+			PRAGMA busy_timeout=60000;
 		`)
 		if err != nil {
 			c.Close()
 			return nil, err
 		}
+		c.reusable = true
+	} else {
+		s, _, err := c.conn.Prepare(`
+			SELECT * FROM
+				PRAGMA_locking_mode,
+				PRAGMA_query_only;
+		`)
+		if err != nil {
+			c.Close()
+			return nil, err
+		}
+		if s.Step() {
+			c.reusable = s.ColumnText(0) == "normal"
+			c.readOnly = s.ColumnRawText(1)[0] // 0 or 1
+		}
+		err = s.Close()
+		if err != nil {
+			c.Close()
+			return nil, err
+		}
 	}
-
-	return conn{
-		conn:    c,
-		txBegin: txBegin,
-	}, nil
+	return c, nil
 }
 
 type conn struct {
-	conn     *sqlite3.Conn
-	txBegin  string
-	txCommit string
+	conn       *sqlite3.Conn
+	txBegin    string
+	txCommit   string
+	txRollback string
+	reusable   bool
+	readOnly   byte
 }
 
 var (
 	// Ensure these interfaces are implemented:
 	_ driver.ExecerContext = conn{}
 	_ driver.ConnBeginTx   = conn{}
+	_ driver.Validator     = conn{}
 	_ sqlite3.DriverConn   = conn{}
 )
 
@@ -102,27 +123,36 @@ func (c conn) Close() error {
 	return c.conn.Close()
 }
 
+func (c conn) IsValid() bool {
+	return c.reusable
+}
+
 func (c conn) Begin() (driver.Tx, error) {
 	return c.BeginTx(context.Background(), driver.TxOptions{})
 }
 
-func (c conn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
-	switch opts.Isolation {
-	default:
-		return nil, isolationErr
-	case driver.IsolationLevel(sql.LevelDefault):
-	case driver.IsolationLevel(sql.LevelSerializable):
-	}
-
+func (c conn) BeginTx(_ context.Context, opts driver.TxOptions) (driver.Tx, error) {
 	txBegin := c.txBegin
 	c.txCommit = `COMMIT`
+	c.txRollback = `ROLLBACK`
+
 	if opts.ReadOnly {
-		c.txCommit = `
-			ROLLBACK;
-			PRAGMA query_only=` + c.conn.Pragma("query_only")[0]
 		txBegin = `
 			BEGIN deferred;
 			PRAGMA query_only=on`
+		c.txCommit = `
+			ROLLBACK;
+			PRAGMA query_only=` + string(c.readOnly)
+		c.txRollback = c.txCommit
+	}
+
+	switch opts.Isolation {
+	default:
+		return nil, util.IsolationErr
+	case
+		driver.IsolationLevel(sql.LevelDefault),
+		driver.IsolationLevel(sql.LevelSerializable):
+		break
 	}
 
 	err := c.conn.Exec(txBegin)
@@ -134,14 +164,14 @@ func (c conn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, er
 
 func (c conn) Commit() error {
 	err := c.conn.Exec(c.txCommit)
-	if err != nil {
+	if err != nil && !c.conn.GetAutocommit() {
 		c.Rollback()
 	}
 	return err
 }
 
 func (c conn) Rollback() error {
-	return c.conn.Exec(`ROLLBACK`)
+	return c.conn.Exec(c.txRollback)
 }
 
 func (c conn) Prepare(query string) (driver.Stmt, error) {
@@ -159,7 +189,7 @@ func (c conn) Prepare(query string) (driver.Stmt, error) {
 		if st != nil {
 			s.Close()
 			st.Close()
-			return nil, tailErr
+			return nil, util.TailErr
 		}
 	}
 	return stmt{s, c.conn}, nil
@@ -183,13 +213,10 @@ func (c conn) ExecContext(ctx context.Context, query string, args []driver.Named
 		return nil, err
 	}
 
-	return result{
-		c.conn.LastInsertRowID(),
-		c.conn.Changes(),
-	}, nil
+	return newResult(c.conn), nil
 }
 
-func (c conn) Savepoint() (release func(*error)) {
+func (c conn) Savepoint() sqlite3.Savepoint {
 	return c.conn.Savepoint()
 }
 
@@ -197,6 +224,10 @@ func (c conn) OpenBlob(db, table, column string, row int64, write bool) (*sqlite
 	return c.conn.OpenBlob(db, table, column, row, write)
 }
 
+func (c conn) SetInterrupt(ctx context.Context) (old context.Context) {
+	return c.conn.SetInterrupt(ctx)
+}
+
 type stmt struct {
 	stmt *sqlite3.Stmt
 	conn *sqlite3.Conn
@@ -246,10 +277,7 @@ func (s stmt) ExecContext(ctx context.Context, args []driver.NamedValue) (driver
 		return nil, err
 	}
 
-	return result{
-		int64(s.conn.LastInsertRowID()),
-		int64(s.conn.Changes()),
-	}, nil
+	return newResult(s.conn), nil
 }
 
 func (s stmt) QueryContext(ctx context.Context, args []driver.NamedValue) (driver.Rows, error) {
@@ -288,11 +316,11 @@ func (s stmt) QueryContext(ctx context.Context, args []driver.NamedValue) (drive
 			case sqlite3.ZeroBlob:
 				err = s.stmt.BindZeroBlob(id, int64(a))
 			case time.Time:
-				err = s.stmt.BindText(id, a.Format(time.RFC3339Nano))
+				err = s.stmt.BindTime(id, a, sqlite3.TimeFormatDefault)
 			case nil:
 				err = s.stmt.BindNull(id)
 			default:
-				panic(assertErr)
+				panic(util.AssertErr())
 			}
 		}
 		if err != nil {
@@ -313,6 +341,17 @@ func (s stmt) CheckNamedValue(arg *driver.NamedValue) error {
 	}
 }
 
+func newResult(c *sqlite3.Conn) driver.Result {
+	rows := c.Changes()
+	if rows != 0 {
+		id := c.LastInsertRowID()
+		if id != 0 {
+			return result{id, rows}
+		}
+	}
+	return resultRowsAffected(rows)
+}
+
 type result struct{ lastInsertId, rowsAffected int64 }
 
 func (r result) LastInsertId() (int64, error) {
@@ -323,6 +362,16 @@ func (r result) RowsAffected() (int64, error) {
 	return r.rowsAffected, nil
 }
 
+type resultRowsAffected int64
+
+func (r resultRowsAffected) LastInsertId() (int64, error) {
+	return 0, nil
+}
+
+func (r resultRowsAffected) RowsAffected() (int64, error) {
+	return int64(r), nil
+}
+
 type rows struct {
 	ctx  context.Context
 	stmt *sqlite3.Stmt
@@ -359,11 +408,10 @@ func (r rows) Next(dest []driver.Value) error {
 			dest[i] = r.stmt.ColumnInt64(i)
 		case sqlite3.FLOAT:
 			dest[i] = r.stmt.ColumnFloat(i)
-		case sqlite3.TEXT:
-			dest[i] = maybeTime(r.stmt.ColumnText(i))
 		case sqlite3.BLOB:
-			buf, _ := dest[i].([]byte)
-			dest[i] = r.stmt.ColumnBlob(i, buf)
+			dest[i] = r.stmt.ColumnRawBlob(i)
+		case sqlite3.TEXT:
+			dest[i] = stringOrTime(r.stmt.ColumnRawText(i))
 		case sqlite3.NULL:
 			if buf, ok := dest[i].([]byte); ok {
 				dest[i] = buf[0:0]
@@ -371,7 +419,7 @@ func (r rows) Next(dest []driver.Value) error {
 				dest[i] = nil
 			}
 		default:
-			panic(assertErr)
+			panic(util.AssertErr())
 		}
 	}
 

driver/driver_test.go

@@ -1,4 +1,3 @@
-// Package driver provides a database/sql driver for SQLite.
 package driver
 
 import (
@@ -12,6 +11,7 @@ import (
 	"time"
 
 	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
 )
 
 func Test_Open_dir(t *testing.T) {
@@ -134,14 +134,16 @@ func Test_BeginTx(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	db, err := sql.Open("sqlite3", filepath.Join(t.TempDir(), "test.db"))
+	db, err := sql.Open("sqlite3", "file:"+
+		filepath.ToSlash(filepath.Join(t.TempDir(), "test.db"))+
+		"?_txlock=exclusive&_pragma=busy_timeout(0)")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer db.Close()
 
 	_, err = db.BeginTx(ctx, &sql.TxOptions{Isolation: sql.LevelReadCommitted})
-	if err.Error() != string(isolationErr) {
+	if err.Error() != string(util.IsolationErr) {
 		t.Error("want isolationErr")
 	}
 
@@ -219,7 +221,7 @@ func Test_Prepare(t *testing.T) {
 	}
 
 	_, err = db.Prepare(`SELECT 1; SELECT 2`)
-	if err.Error() != string(tailErr) {
+	if err.Error() != string(util.TailErr) {
 		t.Error("want tailErr")
 	}
 }
@@ -297,7 +299,7 @@ func Test_QueryRow_blob_null(t *testing.T) {
 
 	want := [][]byte{nil, {0xca, 0xfe}, {0xba, 0xbe}, nil}
 	for i := 0; rows.Next(); i++ {
-		var buf []byte
+		var buf sql.RawBytes
 		err = rows.Scan(&buf)
 		if err != nil {
 			t.Fatal(err)

driver/error.go

@@ -1,11 +0,0 @@
-package driver
-
-type errorString string
-
-func (e errorString) Error() string { return string(e) }
-
-const (
-	assertErr    = errorString("sqlite3: assertion failed")
-	tailErr      = errorString("sqlite3: multiple statements")
-	isolationErr = errorString("sqlite3: unsupported isolation level")
-)

driver/example_test.go

@@ -28,8 +28,8 @@ func Example() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	defer db.Close()
 	defer os.Remove("./recordings.db")
+	defer db.Close()
 
 	// Create a table with some data in it.
 	err = albumsSetup()

driver/time.go

@@ -9,23 +9,23 @@ import (
 // if it roundtrips back to the same string.
 // This way times can be persisted to, and recovered from, the database,
 // but if a string is needed, [database/sql] will recover the same string.
-func maybeTime(text string) driver.Value {
+func stringOrTime(text []byte) driver.Value {
 	// Weed out (some) values that can't possibly be
 	// [time.RFC3339Nano] timestamps.
 	if len(text) < len("2006-01-02T15:04:05Z") {
-		return text
+		return string(text)
 	}
 	if len(text) > len(time.RFC3339Nano) {
-		return text
+		return string(text)
 	}
 	if text[4] != '-' || text[10] != 'T' || text[16] != ':' {
-		return text
+		return string(text)
 	}
 
 	// Slow path.
-	date, err := time.Parse(time.RFC3339Nano, text)
-	if err == nil && date.Format(time.RFC3339Nano) == text {
+	date, err := time.Parse(time.RFC3339Nano, string(text))
+	if err == nil && date.Format(time.RFC3339Nano) == string(text) {
 		return date
 	}
-	return text
+	return string(text)
 }

driver/time_test.go

@@ -6,7 +6,7 @@ import (
 )
 
 // This checks that any string can be recovered as the same string.
-func Fuzz_maybeTime_1(f *testing.F) {
+func Fuzz_stringOrTime_1(f *testing.F) {
 	f.Add("")
 	f.Add(" ")
 	f.Add("SQLite")
@@ -22,7 +22,7 @@ func Fuzz_maybeTime_1(f *testing.F) {
 	f.Add("Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.")
 
 	f.Fuzz(func(t *testing.T, str string) {
-		value := maybeTime(str)
+		value := stringOrTime([]byte(str))
 
 		switch v := value.(type) {
 		case time.Time:
@@ -48,7 +48,7 @@ func Fuzz_maybeTime_1(f *testing.F) {
 
 // This checks that any [time.Time] can be recovered as a [time.Time],
 // with nanosecond accuracy, and preserving any timezone offset.
-func Fuzz_maybeTime_2(f *testing.F) {
+func Fuzz_stringOrTime_2(f *testing.F) {
 	f.Add(0, 0)
 	f.Add(0, 1)
 	f.Add(0, -1)
@@ -59,7 +59,7 @@ func Fuzz_maybeTime_2(f *testing.F) {
 	f.Add(-763421161058, 222_222_222) // twosday, year 22222BC
 
 	checkTime := func(t *testing.T, date time.Time) {
-		value := maybeTime(date.Format(time.RFC3339Nano))
+		value := stringOrTime([]byte(date.Format(time.RFC3339Nano)))
 
 		switch v := value.(type) {
 		case time.Time:

driver_test.go

@@ -20,8 +20,8 @@ func ExampleDriverConn() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	defer db.Close()
 	defer os.Remove("demo.db")
+	defer db.Close()
 
 	ctx := context.Background()
 
@@ -48,7 +48,8 @@ func ExampleDriverConn() {
 
 	err = conn.Raw(func(driverConn any) error {
 		conn := driverConn.(sqlite3.DriverConn)
-		defer conn.Savepoint()(&err)
+		savept := conn.Savepoint()
+		defer savept.Release(&err)
 
 		blob, err := conn.OpenBlob("main", "test", "col", id, true)
 		if err != nil {

embed/README.md

@@ -0,0 +1,23 @@
+# Embeddable WASM build of SQLite
+
+This folder includes an embeddable WASM build of SQLite 3.42.0 for use with
+[`github.com/ncruces/go-sqlite3`](https://pkg.go.dev/github.com/ncruces/go-sqlite3).
+
+The following optional features are compiled in:
+- [math functions](https://www.sqlite.org/lang_mathfunc.html)
+- [FTS3/4](https://www.sqlite.org/fts3.html)/[5](https://www.sqlite.org/fts5.html)
+- [JSON](https://www.sqlite.org/json1.html)
+- [R*Tree](https://www.sqlite.org/rtree.html)
+- [GeoPoly](https://www.sqlite.org/geopoly.html)
+- [base64](https://github.com/sqlite/sqlite/blob/master/ext/misc/base64.c)
+- [decimal](https://github.com/sqlite/sqlite/blob/master/ext/misc/decimal.c)
+- [regexp](https://github.com/sqlite/sqlite/blob/master/ext/misc/regexp.c)
+- [series](https://github.com/sqlite/sqlite/blob/master/ext/misc/series.c)
+- [uint](https://github.com/sqlite/sqlite/blob/master/ext/misc/uint.c)
+- [uuid](https://github.com/sqlite/sqlite/blob/master/ext/misc/uuid.c)
+- [time](../sqlite3/time.c)
+
+See the [configuration options](../sqlite3/sqlite_cfg.h).
+
+Built using [`wasi-sdk`](https://github.com/WebAssembly/wasi-sdk),
+and [`binaryen`](https://github.com/WebAssembly/binaryen).

embed/build.sh

@@ -1,63 +1,27 @@
 #!/usr/bin/env bash
-set -eo pipefail
+set -euo pipefail
 
 cd -P -- "$(dirname -- "$0")"
 
-# download SQLite
-../sqlite3/download.sh
+ROOT=../
+BINARYEN="$ROOT/tools/binaryen-version_112/bin"
+WASI_SDK="$ROOT/tools/wasi-sdk-20.0/bin"
 
-# build SQLite
-zig cc --target=wasm32-wasi -flto -g0 -Os \
-  -o sqlite3.wasm ../sqlite3/amalg.c \
+"$WASI_SDK/clang" --target=wasm32-wasi -flto -g0 -O2 \
+	-o sqlite3.wasm "$ROOT/sqlite3/main.c" \
+	-I"$ROOT/sqlite3" \
+	-mexec-model=reactor \
 	-mmutable-globals \
 	-mbulk-memory -mreference-types \
 	-mnontrapping-fptoint -msign-ext \
-	-D_HAVE_SQLITE_CONFIG_H \
-	-Wl,--export=free \
-	-Wl,--export=malloc \
-	-Wl,--export=malloc_destructor \
-	-Wl,--export=sqlite3_errcode \
-	-Wl,--export=sqlite3_errstr \
-	-Wl,--export=sqlite3_errmsg \
-	-Wl,--export=sqlite3_error_offset \
-	-Wl,--export=sqlite3_open_v2 \
-	-Wl,--export=sqlite3_close \
-	-Wl,--export=sqlite3_prepare_v3 \
-	-Wl,--export=sqlite3_finalize \
-	-Wl,--export=sqlite3_reset \
-	-Wl,--export=sqlite3_step \
-	-Wl,--export=sqlite3_exec \
-	-Wl,--export=sqlite3_clear_bindings \
-	-Wl,--export=sqlite3_bind_parameter_count \
-	-Wl,--export=sqlite3_bind_parameter_index \
-	-Wl,--export=sqlite3_bind_parameter_name \
-	-Wl,--export=sqlite3_bind_null \
-	-Wl,--export=sqlite3_bind_int64 \
-	-Wl,--export=sqlite3_bind_double \
-	-Wl,--export=sqlite3_bind_text64 \
-	-Wl,--export=sqlite3_bind_blob64 \
-	-Wl,--export=sqlite3_bind_zeroblob64 \
-	-Wl,--export=sqlite3_column_count \
-	-Wl,--export=sqlite3_column_name \
-	-Wl,--export=sqlite3_column_type \
-	-Wl,--export=sqlite3_column_int64 \
-	-Wl,--export=sqlite3_column_double \
-	-Wl,--export=sqlite3_column_text \
-	-Wl,--export=sqlite3_column_blob \
-	-Wl,--export=sqlite3_column_bytes \
-	-Wl,--export=sqlite3_blob_open \
-	-Wl,--export=sqlite3_blob_close \
-	-Wl,--export=sqlite3_blob_bytes \
-	-Wl,--export=sqlite3_blob_read \
-	-Wl,--export=sqlite3_blob_write \
-	-Wl,--export=sqlite3_blob_reopen \
-	-Wl,--export=sqlite3_get_autocommit \
-	-Wl,--export=sqlite3_last_insert_rowid \
-	-Wl,--export=sqlite3_changes64 \
-	-Wl,--export=sqlite3_unlock_notify \
-	-Wl,--export=sqlite3_backup_init \
-	-Wl,--export=sqlite3_backup_step \
-	-Wl,--export=sqlite3_backup_finish \
-	-Wl,--export=sqlite3_backup_remaining \
-	-Wl,--export=sqlite3_backup_pagecount \
-	-Wl,--export=sqlite3_interrupt_offset \
+	-Wl,--initial-memory=327680 \
+	-Wl,--stack-first \
+	-Wl,--import-undefined \
+	$(awk '{print "-Wl,--export="$0}' exports.txt)
+
+trap 'rm -f sqlite3.tmp' EXIT
+"$BINARYEN/wasm-ctor-eval" -g -c _initialize sqlite3.wasm -o sqlite3.tmp
+"$BINARYEN/wasm-opt" -g -O2 sqlite3.tmp -o sqlite3.wasm \
+	--enable-multivalue --enable-mutable-globals \
+	--enable-bulk-memory --enable-reference-types \
+	--enable-nontrapping-float-to-int --enable-sign-ext

embed/exports.txt

@@ -0,0 +1,47 @@
+free
+malloc
+malloc_destructor
+sqlite3_errcode
+sqlite3_errstr
+sqlite3_errmsg
+sqlite3_error_offset
+sqlite3_open_v2
+sqlite3_close
+sqlite3_close_v2
+sqlite3_prepare_v3
+sqlite3_finalize
+sqlite3_reset
+sqlite3_step
+sqlite3_exec
+sqlite3_clear_bindings
+sqlite3_bind_parameter_count
+sqlite3_bind_parameter_index
+sqlite3_bind_parameter_name
+sqlite3_bind_null
+sqlite3_bind_int64
+sqlite3_bind_double
+sqlite3_bind_text64
+sqlite3_bind_blob64
+sqlite3_bind_zeroblob64
+sqlite3_column_count
+sqlite3_column_name
+sqlite3_column_type
+sqlite3_column_int64
+sqlite3_column_double
+sqlite3_column_text
+sqlite3_column_blob
+sqlite3_column_bytes
+sqlite3_blob_open
+sqlite3_blob_close
+sqlite3_blob_bytes
+sqlite3_blob_read
+sqlite3_blob_write
+sqlite3_blob_reopen
+sqlite3_get_autocommit
+sqlite3_last_insert_rowid
+sqlite3_changes64
+sqlite3_backup_init
+sqlite3_backup_step
+sqlite3_backup_finish
+sqlite3_backup_remaining
+sqlite3_backup_pagecount

embed/init.go

@@ -4,9 +4,6 @@
 // with an appropriate build of SQLite:
 //
 //	import _ "github.com/ncruces/go-sqlite3/embed"
-//
-// You can obtain this build of SQLite from:
-// https://github.com/ncruces/go-sqlite3/tree/main/embed
 package embed
 
 import (

error.go

@@ -1,19 +1,20 @@
 package sqlite3
 
 import (
-	"runtime"
 	"strconv"
 	"strings"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
 )
 
 // Error wraps an SQLite Error Code.
 //
 // https://www.sqlite.org/c3ref/errcode.html
 type Error struct {
-	code uint64
 	str  string
 	msg  string
 	sql  string
+	code uint64
 }
 
 // Code returns the primary error code for this error.
@@ -84,72 +85,7 @@ func (e *Error) SQL() string {
 
 // Error implements the error interface.
 func (e ErrorCode) Error() string {
-	switch e {
-	case _OK:
-		return "sqlite3: not an error"
-	case _ROW:
-		return "sqlite3: another row available"
-	case _DONE:
-		return "sqlite3: no more rows available"
-
-	case ERROR:
-		return "sqlite3: SQL logic error"
-	case INTERNAL:
-		break
-	case PERM:
-		return "sqlite3: access permission denied"
-	case ABORT:
-		return "sqlite3: query aborted"
-	case BUSY:
-		return "sqlite3: database is locked"
-	case LOCKED:
-		return "sqlite3: database table is locked"
-	case NOMEM:
-		return "sqlite3: out of memory"
-	case READONLY:
-		return "sqlite3: attempt to write a readonly database"
-	case INTERRUPT:
-		return "sqlite3: interrupted"
-	case IOERR:
-		return "sqlite3: disk I/O error"
-	case CORRUPT:
-		return "sqlite3: database disk image is malformed"
-	case NOTFOUND:
-		return "sqlite3: unknown operation"
-	case FULL:
-		return "sqlite3: database or disk is full"
-	case CANTOPEN:
-		return "sqlite3: unable to open database file"
-	case PROTOCOL:
-		return "sqlite3: locking protocol"
-	case FORMAT:
-		break
-	case SCHEMA:
-		return "sqlite3: database schema has changed"
-	case TOOBIG:
-		return "sqlite3: string or blob too big"
-	case CONSTRAINT:
-		return "sqlite3: constraint failed"
-	case MISMATCH:
-		return "sqlite3: datatype mismatch"
-	case MISUSE:
-		return "sqlite3: bad parameter or other API misuse"
-	case NOLFS:
-		break
-	case AUTH:
-		return "sqlite3: authorization denied"
-	case EMPTY:
-		break
-	case RANGE:
-		return "sqlite3: column index out of range"
-	case NOTADB:
-		return "sqlite3: file is not a database"
-	case NOTICE:
-		return "sqlite3: notification message"
-	case WARNING:
-		return "sqlite3: warning message"
-	}
-	return "sqlite3: unknown error"
+	return util.ErrorCodeString(uint32(e))
 }
 
 // Temporary returns true for [BUSY] errors.
@@ -159,17 +95,7 @@ func (e ErrorCode) Temporary() bool {
 
 // Error implements the error interface.
 func (e ExtendedErrorCode) Error() string {
-	switch x := ErrorCode(e); {
-	case e == ABORT_ROLLBACK:
-		return "sqlite3: abort due to ROLLBACK"
-	case x < _ROW:
-		return x.Error()
-	case e == _ROW:
-		return "sqlite3: another row available"
-	case e == _DONE:
-		return "sqlite3: no more rows available"
-	}
-	return "sqlite3: unknown error"
+	return util.ErrorCodeString(uint32(e))
 }
 
 // Is tests whether this error matches a given [ErrorCode].
@@ -187,31 +113,3 @@ func (e ExtendedErrorCode) Temporary() bool {
 func (e ExtendedErrorCode) Timeout() bool {
 	return e == BUSY_TIMEOUT
 }
-
-type errorString string
-
-func (e errorString) Error() string { return string(e) }
-
-const (
-	nilErr      = errorString("sqlite3: invalid memory address or null pointer dereference")
-	oomErr      = errorString("sqlite3: out of memory")
-	rangeErr    = errorString("sqlite3: index out of range")
-	noNulErr    = errorString("sqlite3: missing NUL terminator")
-	noGlobalErr = errorString("sqlite3: could not find global: ")
-	noFuncErr   = errorString("sqlite3: could not find function: ")
-	binaryErr   = errorString("sqlite3: no SQLite binary embed/set/loaded")
-	timeErr     = errorString("sqlite3: invalid time value")
-	emptyErr    = errorString("sqlite3: empty statement")
-	tailErr     = errorString("sqlite3: non-empty tail")
-	notImplErr  = errorString("sqlite3: not implemented")
-	whenceErr   = errorString("sqlite3: invalid whence")
-	offsetErr   = errorString("sqlite3: invalid offset")
-)
-
-func assertErr() errorString {
-	msg := "sqlite3: assertion failed"
-	if _, file, line, ok := runtime.Caller(1); ok {
-		msg += " (" + file + ":" + strconv.Itoa(line) + ")"
-	}
-	return errorString(msg)
-}

error_test.go

@@ -1,15 +1,16 @@
 package sqlite3
 
 import (
-	"context"
 	"errors"
 	"strings"
 	"testing"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
 )
 
 func Test_assertErr(t *testing.T) {
-	err := assertErr()
-	if s := err.Error(); !strings.HasPrefix(s, "sqlite3: assertion failed") || !strings.HasSuffix(s, "error_test.go:11)") {
+	err := util.AssertErr()
+	if s := err.Error(); !strings.HasPrefix(s, "sqlite3: assertion failed") || !strings.HasSuffix(s, "error_test.go:12)") {
 		t.Errorf("got %q", s)
 	}
 }
@@ -120,10 +121,8 @@ func Test_ErrorCode_Error(t *testing.T) {
 	// Test all error codes.
 	for i := 0; i == int(ErrorCode(i)); i++ {
 		want := "sqlite3: "
-		r, _ := db.api.errstr.Call(context.TODO(), uint64(i))
-		if r != nil {
-			want += db.mem.readString(uint32(r[0]), _MAX_STRING)
-		}
+		r := db.call(db.api.errstr, uint64(i))
+		want += util.ReadString(db.mod, uint32(r[0]), _MAX_STRING)
 
 		got := ErrorCode(i).Error()
 		if got != want {
@@ -144,10 +143,8 @@ func Test_ExtendedErrorCode_Error(t *testing.T) {
 	// Test all extended error codes.
 	for i := 0; i == int(ExtendedErrorCode(i)); i++ {
 		want := "sqlite3: "
-		r, _ := db.api.errstr.Call(context.TODO(), uint64(i))
-		if r != nil {
-			want += db.mem.readString(uint32(r[0]), _MAX_STRING)
-		}
+		r := db.call(db.api.errstr, uint64(i))
+		want += util.ReadString(db.mod, uint32(r[0]), _MAX_STRING)
 
 		got := ExtendedErrorCode(i).Error()
 		if got != want {

example_test.go

@@ -26,7 +26,11 @@ func Example() {
 		log.Fatal(err)
 	}
 
-	stmt := db.MustPrepare(`SELECT id, name FROM users`)
+	stmt, _, err := db.Prepare(`SELECT id, name FROM users`)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer stmt.Close()
 
 	for stmt.Step() {
 		fmt.Println(stmt.ColumnInt(0), stmt.ColumnText(1))

go.mod

@@ -4,7 +4,9 @@ go 1.19
 
 require (
 	github.com/ncruces/julianday v0.1.5
-	github.com/tetratelabs/wazero v1.0.0-pre.9
-	golang.org/x/sync v0.1.0
-	golang.org/x/sys v0.5.0
+	github.com/tetratelabs/wazero v1.1.0
+	golang.org/x/sync v0.2.0
+	golang.org/x/sys v0.8.0
 )
+
+retract v0.4.0 // tagged from the wrong branch

go.sum

@@ -1,8 +1,8 @@
 github.com/ncruces/julianday v0.1.5 h1:hDJ9ejiMp3DHsoZ5KW4c1lwfMjbARS7u/gbYcd0FBZk=
 github.com/ncruces/julianday v0.1.5/go.mod h1:Dusn2KvZrrovOMJuOt0TNXL6tB7U2E8kvza5fFc9G7g=
-github.com/tetratelabs/wazero v1.0.0-pre.9 h1:2uVdi2bvTi/JQxG2cp3LRm2aRadd3nURn5jcfbvqZcw=
-github.com/tetratelabs/wazero v1.0.0-pre.9/go.mod h1:wYx2gNRg8/WihJfSDxA1TIL8H+GkfLYm+bIfbblu9VQ=
-golang.org/x/sync v0.1.0 h1:wsuoTGHzEhffawBOhz5CYhcrV4IdKZbEyZjBMuTp12o=
-golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sys v0.5.0 h1:MUK/U/4lj1t1oPg0HfuXDN/Z1wv31ZJ/YcPiGccS4DU=
-golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+github.com/tetratelabs/wazero v1.1.0 h1:EByoAhC+QcYpwSZJSs/aV0uokxPwBgKxfiokSUwAknQ=
+github.com/tetratelabs/wazero v1.1.0/go.mod h1:wYx2gNRg8/WihJfSDxA1TIL8H+GkfLYm+bIfbblu9VQ=
+golang.org/x/sync v0.2.0 h1:PUR+T4wwASmuSTYdKjYHI5TD22Wy5ogLU5qZCOLxBrI=
+golang.org/x/sync v0.2.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.8.0 h1:EBmGv8NaZBZTWvrbjNoL6HVt+IVy3QDQpJs7VRIw3tU=
+golang.org/x/sys v0.8.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

internal/util/const.go

@@ -0,0 +1,116 @@
+package util
+
+// https://sqlite.com/matrix/rescode.html
+const (
+	OK = 0 /* Successful result */
+
+	ERROR      = 1  /* Generic error */
+	INTERNAL   = 2  /* Internal logic error in SQLite */
+	PERM       = 3  /* Access permission denied */
+	ABORT      = 4  /* Callback routine requested an abort */
+	BUSY       = 5  /* The database file is locked */
+	LOCKED     = 6  /* A table in the database is locked */
+	NOMEM      = 7  /* A malloc() failed */
+	READONLY   = 8  /* Attempt to write a readonly database */
+	INTERRUPT  = 9  /* Operation terminated by sqlite3_interrupt() */
+	IOERR      = 10 /* Some kind of disk I/O error occurred */
+	CORRUPT    = 11 /* The database disk image is malformed */
+	NOTFOUND   = 12 /* Unknown opcode in sqlite3_file_control() */
+	FULL       = 13 /* Insertion failed because database is full */
+	CANTOPEN   = 14 /* Unable to open the database file */
+	PROTOCOL   = 15 /* Database lock protocol error */
+	EMPTY      = 16 /* Internal use only */
+	SCHEMA     = 17 /* The database schema changed */
+	TOOBIG     = 18 /* String or BLOB exceeds size limit */
+	CONSTRAINT = 19 /* Abort due to constraint violation */
+	MISMATCH   = 20 /* Data type mismatch */
+	MISUSE     = 21 /* Library used incorrectly */
+	NOLFS      = 22 /* Uses OS features not supported on host */
+	AUTH       = 23 /* Authorization denied */
+	FORMAT     = 24 /* Not used */
+	RANGE      = 25 /* 2nd parameter to sqlite3_bind out of range */
+	NOTADB     = 26 /* File opened that is not a database file */
+	NOTICE     = 27 /* Notifications from sqlite3_log() */
+	WARNING    = 28 /* Warnings from sqlite3_log() */
+
+	ROW  = 100 /* sqlite3_step() has another row ready */
+	DONE = 101 /* sqlite3_step() has finished executing */
+
+	ERROR_MISSING_COLLSEQ   = ERROR | (1 << 8)
+	ERROR_RETRY             = ERROR | (2 << 8)
+	ERROR_SNAPSHOT          = ERROR | (3 << 8)
+	IOERR_READ              = IOERR | (1 << 8)
+	IOERR_SHORT_READ        = IOERR | (2 << 8)
+	IOERR_WRITE             = IOERR | (3 << 8)
+	IOERR_FSYNC             = IOERR | (4 << 8)
+	IOERR_DIR_FSYNC         = IOERR | (5 << 8)
+	IOERR_TRUNCATE          = IOERR | (6 << 8)
+	IOERR_FSTAT             = IOERR | (7 << 8)
+	IOERR_UNLOCK            = IOERR | (8 << 8)
+	IOERR_RDLOCK            = IOERR | (9 << 8)
+	IOERR_DELETE            = IOERR | (10 << 8)
+	IOERR_BLOCKED           = IOERR | (11 << 8)
+	IOERR_NOMEM             = IOERR | (12 << 8)
+	IOERR_ACCESS            = IOERR | (13 << 8)
+	IOERR_CHECKRESERVEDLOCK = IOERR | (14 << 8)
+	IOERR_LOCK              = IOERR | (15 << 8)
+	IOERR_CLOSE             = IOERR | (16 << 8)
+	IOERR_DIR_CLOSE         = IOERR | (17 << 8)
+	IOERR_SHMOPEN           = IOERR | (18 << 8)
+	IOERR_SHMSIZE           = IOERR | (19 << 8)
+	IOERR_SHMLOCK           = IOERR | (20 << 8)
+	IOERR_SHMMAP            = IOERR | (21 << 8)
+	IOERR_SEEK              = IOERR | (22 << 8)
+	IOERR_DELETE_NOENT      = IOERR | (23 << 8)
+	IOERR_MMAP              = IOERR | (24 << 8)
+	IOERR_GETTEMPPATH       = IOERR | (25 << 8)
+	IOERR_CONVPATH          = IOERR | (26 << 8)
+	IOERR_VNODE             = IOERR | (27 << 8)
+	IOERR_AUTH              = IOERR | (28 << 8)
+	IOERR_BEGIN_ATOMIC      = IOERR | (29 << 8)
+	IOERR_COMMIT_ATOMIC     = IOERR | (30 << 8)
+	IOERR_ROLLBACK_ATOMIC   = IOERR | (31 << 8)
+	IOERR_DATA              = IOERR | (32 << 8)
+	IOERR_CORRUPTFS         = IOERR | (33 << 8)
+	LOCKED_SHAREDCACHE      = LOCKED | (1 << 8)
+	LOCKED_VTAB             = LOCKED | (2 << 8)
+	BUSY_RECOVERY           = BUSY | (1 << 8)
+	BUSY_SNAPSHOT           = BUSY | (2 << 8)
+	BUSY_TIMEOUT            = BUSY | (3 << 8)
+	CANTOPEN_NOTEMPDIR      = CANTOPEN | (1 << 8)
+	CANTOPEN_ISDIR          = CANTOPEN | (2 << 8)
+	CANTOPEN_FULLPATH       = CANTOPEN | (3 << 8)
+	CANTOPEN_CONVPATH       = CANTOPEN | (4 << 8)
+	CANTOPEN_DIRTYWAL       = CANTOPEN | (5 << 8) /* Not Used */
+	CANTOPEN_SYMLINK        = CANTOPEN | (6 << 8)
+	CORRUPT_VTAB            = CORRUPT | (1 << 8)
+	CORRUPT_SEQUENCE        = CORRUPT | (2 << 8)
+	CORRUPT_INDEX           = CORRUPT | (3 << 8)
+	READONLY_RECOVERY       = READONLY | (1 << 8)
+	READONLY_CANTLOCK       = READONLY | (2 << 8)
+	READONLY_ROLLBACK       = READONLY | (3 << 8)
+	READONLY_DBMOVED        = READONLY | (4 << 8)
+	READONLY_CANTINIT       = READONLY | (5 << 8)
+	READONLY_DIRECTORY      = READONLY | (6 << 8)
+	ABORT_ROLLBACK          = ABORT | (2 << 8)
+	CONSTRAINT_CHECK        = CONSTRAINT | (1 << 8)
+	CONSTRAINT_COMMITHOOK   = CONSTRAINT | (2 << 8)
+	CONSTRAINT_FOREIGNKEY   = CONSTRAINT | (3 << 8)
+	CONSTRAINT_FUNCTION     = CONSTRAINT | (4 << 8)
+	CONSTRAINT_NOTNULL      = CONSTRAINT | (5 << 8)
+	CONSTRAINT_PRIMARYKEY   = CONSTRAINT | (6 << 8)
+	CONSTRAINT_TRIGGER      = CONSTRAINT | (7 << 8)
+	CONSTRAINT_UNIQUE       = CONSTRAINT | (8 << 8)
+	CONSTRAINT_VTAB         = CONSTRAINT | (9 << 8)
+	CONSTRAINT_ROWID        = CONSTRAINT | (10 << 8)
+	CONSTRAINT_PINNED       = CONSTRAINT | (11 << 8)
+	CONSTRAINT_DATATYPE     = CONSTRAINT | (12 << 8)
+	NOTICE_RECOVER_WAL      = NOTICE | (1 << 8)
+	NOTICE_RECOVER_ROLLBACK = NOTICE | (2 << 8)
+	NOTICE_RBU              = NOTICE | (3 << 8)
+	WARNING_AUTOINDEX       = WARNING | (1 << 8)
+	AUTH_USER               = AUTH | (1 << 8)
+
+	OK_LOAD_PERMANENTLY = OK | (1 << 8)
+	OK_SYMLINK          = OK | (2 << 8) /* internal use only */
+)

internal/util/error.go

@@ -0,0 +1,115 @@
+package util
+
+import (
+	"fmt"
+	"runtime"
+	"strconv"
+)
+
+type ErrorString string
+
+func (e ErrorString) Error() string { return string(e) }
+
+const (
+	NilErr       = ErrorString("sqlite3: invalid memory address or null pointer dereference")
+	OOMErr       = ErrorString("sqlite3: out of memory")
+	RangeErr     = ErrorString("sqlite3: index out of range")
+	NoNulErr     = ErrorString("sqlite3: missing NUL terminator")
+	NoGlobalErr  = ErrorString("sqlite3: could not find global: ")
+	NoFuncErr    = ErrorString("sqlite3: could not find function: ")
+	BinaryErr    = ErrorString("sqlite3: no SQLite binary embed/set/loaded")
+	TimeErr      = ErrorString("sqlite3: invalid time value")
+	WhenceErr    = ErrorString("sqlite3: invalid whence")
+	OffsetErr    = ErrorString("sqlite3: invalid offset")
+	TailErr      = ErrorString("sqlite3: multiple statements")
+	IsolationErr = ErrorString("sqlite3: unsupported isolation level")
+	NoVFSErr     = ErrorString("sqlite3: no such vfs: ")
+)
+
+func AssertErr() ErrorString {
+	msg := "sqlite3: assertion failed"
+	if _, file, line, ok := runtime.Caller(1); ok {
+		msg += " (" + file + ":" + strconv.Itoa(line) + ")"
+	}
+	return ErrorString(msg)
+}
+
+func Finalizer[T any](skip int) func(*T) {
+	msg := fmt.Sprintf("sqlite3: %T not closed", new(T))
+	if _, file, line, ok := runtime.Caller(skip + 1); ok && skip >= 0 {
+		msg += " (" + file + ":" + strconv.Itoa(line) + ")"
+	}
+	return func(*T) { panic(ErrorString(msg)) }
+}
+
+func ErrorCodeString(rc uint32) string {
+	switch rc {
+	case ABORT_ROLLBACK:
+		return "sqlite3: abort due to ROLLBACK"
+	case ROW:
+		return "sqlite3: another row available"
+	case DONE:
+		return "sqlite3: no more rows available"
+	}
+	switch rc & 0xff {
+	case OK:
+		return "sqlite3: not an error"
+	case ERROR:
+		return "sqlite3: SQL logic error"
+	case INTERNAL:
+		break
+	case PERM:
+		return "sqlite3: access permission denied"
+	case ABORT:
+		return "sqlite3: query aborted"
+	case BUSY:
+		return "sqlite3: database is locked"
+	case LOCKED:
+		return "sqlite3: database table is locked"
+	case NOMEM:
+		return "sqlite3: out of memory"
+	case READONLY:
+		return "sqlite3: attempt to write a readonly database"
+	case INTERRUPT:
+		return "sqlite3: interrupted"
+	case IOERR:
+		return "sqlite3: disk I/O error"
+	case CORRUPT:
+		return "sqlite3: database disk image is malformed"
+	case NOTFOUND:
+		return "sqlite3: unknown operation"
+	case FULL:
+		return "sqlite3: database or disk is full"
+	case CANTOPEN:
+		return "sqlite3: unable to open database file"
+	case PROTOCOL:
+		return "sqlite3: locking protocol"
+	case FORMAT:
+		break
+	case SCHEMA:
+		return "sqlite3: database schema has changed"
+	case TOOBIG:
+		return "sqlite3: string or blob too big"
+	case CONSTRAINT:
+		return "sqlite3: constraint failed"
+	case MISMATCH:
+		return "sqlite3: datatype mismatch"
+	case MISUSE:
+		return "sqlite3: bad parameter or other API misuse"
+	case NOLFS:
+		break
+	case AUTH:
+		return "sqlite3: authorization denied"
+	case EMPTY:
+		break
+	case RANGE:
+		return "sqlite3: column index out of range"
+	case NOTADB:
+		return "sqlite3: file is not a database"
+	case NOTICE:
+		return "sqlite3: notification message"
+	case WARNING:
+		return "sqlite3: warning message"
+	}
+	return "sqlite3: unknown error"
+}

internal/util/func.go

@@ -0,0 +1,102 @@
+package util
+
+import (
+	"context"
+
+	"github.com/tetratelabs/wazero"
+	"github.com/tetratelabs/wazero/api"
+)
+
+type i32 interface{ ~int32 | ~uint32 }
+type i64 interface{ ~int64 | ~uint64 }
+
+type funcII[TR, T0 i32] func(context.Context, api.Module, T0) TR
+
+func (fn funcII[TR, T0]) Call(ctx context.Context, mod api.Module, stack []uint64) {
+	stack[0] = uint64(fn(ctx, mod, T0(stack[0])))
+}
+
+func ExportFuncII[TR, T0 i32](mod wazero.HostModuleBuilder, name string, fn func(context.Context, api.Module, T0) TR) {
+	mod.NewFunctionBuilder().
+		WithGoModuleFunction(funcII[TR, T0](fn),
+			[]api.ValueType{api.ValueTypeI32}, []api.ValueType{api.ValueTypeI32}).
+		Export(name)
+}
+
+type funcIII[TR, T0, T1 i32] func(context.Context, api.Module, T0, T1) TR
+
+func (fn funcIII[TR, T0, T1]) Call(ctx context.Context, mod api.Module, stack []uint64) {
+	stack[0] = uint64(fn(ctx, mod, T0(stack[0]), T1(stack[1])))
+}
+
+func ExportFuncIII[TR, T0, T1 i32](mod wazero.HostModuleBuilder, name string, fn func(context.Context, api.Module, T0, T1) TR) {
+	mod.NewFunctionBuilder().
+		WithGoModuleFunction(funcIII[TR, T0, T1](fn),
+			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI32}, []api.ValueType{api.ValueTypeI32}).
+		Export(name)
+}
+
+type funcIIII[TR, T0, T1, T2 i32] func(context.Context, api.Module, T0, T1, T2) TR
+
+func (fn funcIIII[TR, T0, T1, T2]) Call(ctx context.Context, mod api.Module, stack []uint64) {
+	stack[0] = uint64(fn(ctx, mod, T0(stack[0]), T1(stack[1]), T2(stack[2])))
+}
+
+func ExportFuncIIII[TR, T0, T1, T2 i32](mod wazero.HostModuleBuilder, name string, fn func(context.Context, api.Module, T0, T1, T2) TR) {
+	mod.NewFunctionBuilder().
+		WithGoModuleFunction(funcIIII[TR, T0, T1, T2](fn),
+			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32}, []api.ValueType{api.ValueTypeI32}).
+		Export(name)
+}
+
+type funcIIIII[TR, T0, T1, T2, T3 i32] func(context.Context, api.Module, T0, T1, T2, T3) TR
+
+func (fn funcIIIII[TR, T0, T1, T2, T3]) Call(ctx context.Context, mod api.Module, stack []uint64) {
+	stack[0] = uint64(fn(ctx, mod, T0(stack[0]), T1(stack[1]), T2(stack[2]), T3(stack[3])))
+}
+
+func ExportFuncIIIII[TR, T0, T1, T2, T3 i32](mod wazero.HostModuleBuilder, name string, fn func(context.Context, api.Module, T0, T1, T2, T3) TR) {
+	mod.NewFunctionBuilder().
+		WithGoModuleFunction(funcIIIII[TR, T0, T1, T2, T3](fn),
+			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32}, []api.ValueType{api.ValueTypeI32}).
+		Export(name)
+}
+
+type funcIIIIII[TR, T0, T1, T2, T3, T4 i32] func(context.Context, api.Module, T0, T1, T2, T3, T4) TR
+
+func (fn funcIIIIII[TR, T0, T1, T2, T3, T4]) Call(ctx context.Context, mod api.Module, stack []uint64) {
+	stack[0] = uint64(fn(ctx, mod, T0(stack[0]), T1(stack[1]), T2(stack[2]), T3(stack[3]), T4(stack[4])))
+}
+
+func ExportFuncIIIIII[TR, T0, T1, T2, T3, T4 i32](mod wazero.HostModuleBuilder, name string, fn func(context.Context, api.Module, T0, T1, T2, T3, T4) TR) {
+	mod.NewFunctionBuilder().
+		WithGoModuleFunction(funcIIIIII[TR, T0, T1, T2, T3, T4](fn),
+			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32}, []api.ValueType{api.ValueTypeI32}).
+		Export(name)
+}
+
+type funcIIIIJ[TR, T0, T1, T2 i32, T3 i64] func(context.Context, api.Module, T0, T1, T2, T3) TR
+
+func (fn funcIIIIJ[TR, T0, T1, T2, T3]) Call(ctx context.Context, mod api.Module, stack []uint64) {
+	stack[0] = uint64(fn(ctx, mod, T0(stack[0]), T1(stack[1]), T2(stack[2]), T3(stack[3])))
+}
+
+func ExportFuncIIIIJ[TR, T0, T1, T2 i32, T3 i64](mod wazero.HostModuleBuilder, name string, fn func(context.Context, api.Module, T0, T1, T2, T3) TR) {
+	mod.NewFunctionBuilder().
+		WithGoModuleFunction(funcIIIIJ[TR, T0, T1, T2, T3](fn),
+			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI64}, []api.ValueType{api.ValueTypeI32}).
+		Export(name)
+}
+
+type funcIIJ[TR, T0 i32, T1 i64] func(context.Context, api.Module, T0, T1) TR
+
+func (fn funcIIJ[TR, T0, T1]) Call(ctx context.Context, mod api.Module, stack []uint64) {
+	stack[0] = uint64(fn(ctx, mod, T0(stack[0]), T1(stack[1])))
+}
+
+func ExportFuncIIJ[TR, T0 i32, T1 i64](mod wazero.HostModuleBuilder, name string, fn func(context.Context, api.Module, T0, T1) TR) {
+	mod.NewFunctionBuilder().
+		WithGoModuleFunction(funcIIJ[TR, T0, T1](fn),
+			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI64}, []api.ValueType{api.ValueTypeI32}).
+		Export(name)
+}

internal/util/mem.go

@@ -0,0 +1,110 @@
+package util
+
+import (
+	"bytes"
+	"math"
+
+	"github.com/tetratelabs/wazero/api"
+)
+
+func View(mod api.Module, ptr uint32, size uint64) []byte {
+	if ptr == 0 {
+		panic(NilErr)
+	}
+	if size > math.MaxUint32 {
+		panic(RangeErr)
+	}
+	buf, ok := mod.Memory().Read(ptr, uint32(size))
+	if !ok {
+		panic(RangeErr)
+	}
+	return buf
+}
+
+func ReadUint32(mod api.Module, ptr uint32) uint32 {
+	if ptr == 0 {
+		panic(NilErr)
+	}
+	v, ok := mod.Memory().ReadUint32Le(ptr)
+	if !ok {
+		panic(RangeErr)
+	}
+	return v
+}
+
+func WriteUint32(mod api.Module, ptr uint32, v uint32) {
+	if ptr == 0 {
+		panic(NilErr)
+	}
+	ok := mod.Memory().WriteUint32Le(ptr, v)
+	if !ok {
+		panic(RangeErr)
+	}
+}
+
+func ReadUint64(mod api.Module, ptr uint32) uint64 {
+	if ptr == 0 {
+		panic(NilErr)
+	}
+	v, ok := mod.Memory().ReadUint64Le(ptr)
+	if !ok {
+		panic(RangeErr)
+	}
+	return v
+}
+
+func WriteUint64(mod api.Module, ptr uint32, v uint64) {
+	if ptr == 0 {
+		panic(NilErr)
+	}
+	ok := mod.Memory().WriteUint64Le(ptr, v)
+	if !ok {
+		panic(RangeErr)
+	}
+}
+
+func ReadFloat64(mod api.Module, ptr uint32) float64 {
+	return math.Float64frombits(ReadUint64(mod, ptr))
+}
+
+func WriteFloat64(mod api.Module, ptr uint32, v float64) {
+	WriteUint64(mod, ptr, math.Float64bits(v))
+}
+
+func ReadString(mod api.Module, ptr, maxlen uint32) string {
+	if ptr == 0 {
+		panic(NilErr)
+	}
+	switch maxlen {
+	case 0:
+		return ""
+	case math.MaxUint32:
+		// avoid overflow
+	default:
+		maxlen = maxlen + 1
+	}
+	mem := mod.Memory()
+	buf, ok := mem.Read(ptr, maxlen)
+	if !ok {
+		buf, ok = mem.Read(ptr, mem.Size()-ptr)
+		if !ok {
+			panic(RangeErr)
+		}
+	}
+	if i := bytes.IndexByte(buf, 0); i < 0 {
+		panic(NoNulErr)
+	} else {
+		return string(buf[:i])
+	}
+}
+
+func WriteBytes(mod api.Module, ptr uint32, b []byte) {
+	buf := View(mod, ptr, uint64(len(b)))
+	copy(buf, b)
+}
+
+func WriteString(mod api.Module, ptr uint32, s string) {
+	buf := View(mod, ptr, uint64(len(s)+1))
+	buf[len(s)] = 0
+	copy(buf, s)
+}

internal/util/mem_test.go

@@ -0,0 +1,90 @@
+package util
+
+import (
+	"math"
+	"testing"
+)
+
+func TestView_nil(t *testing.T) {
+	defer func() { _ = recover() }()
+	mock := NewMockModule(128)
+	View(mock, 0, 8)
+	t.Error("want panic")
+}
+
+func TestView_range(t *testing.T) {
+	defer func() { _ = recover() }()
+	mock := NewMockModule(128)
+	View(mock, 126, 8)
+	t.Error("want panic")
+}
+
+func TestView_overflow(t *testing.T) {
+	defer func() { _ = recover() }()
+	mock := NewMockModule(128)
+	View(mock, 1, math.MaxInt64)
+	t.Error("want panic")
+}
+
+func TestReadUint32_nil(t *testing.T) {
+	defer func() { _ = recover() }()
+	mock := NewMockModule(128)
+	ReadUint32(mock, 0)
+	t.Error("want panic")
+}
+
+func TestReadUint32_range(t *testing.T) {
+	defer func() { _ = recover() }()
+	mock := NewMockModule(128)
+	ReadUint32(mock, 126)
+	t.Error("want panic")
+}
+
+func TestReadUint64_nil(t *testing.T) {
+	defer func() { _ = recover() }()
+	mock := NewMockModule(128)
+	ReadUint64(mock, 0)
+	t.Error("want panic")
+}
+
+func TestReadUint64_range(t *testing.T) {
+	defer func() { _ = recover() }()
+	mock := NewMockModule(128)
+	ReadUint64(mock, 126)
+	t.Error("want panic")
+}
+
+func TestWriteUint32_nil(t *testing.T) {
+	defer func() { _ = recover() }()
+	mock := NewMockModule(128)
+	WriteUint32(mock, 0, 1)
+	t.Error("want panic")
+}
+
+func TestWriteUint32_range(t *testing.T) {
+	defer func() { _ = recover() }()
+	mock := NewMockModule(128)
+	WriteUint32(mock, 126, 1)
+	t.Error("want panic")
+}
+
+func TestWriteUint64_nil(t *testing.T) {
+	defer func() { _ = recover() }()
+	mock := NewMockModule(128)
+	WriteUint64(mock, 0, 1)
+	t.Error("want panic")
+}
+
+func TestWriteUint64_range(t *testing.T) {
+	defer func() { _ = recover() }()
+	mock := NewMockModule(128)
+	WriteUint64(mock, 126, 1)
+	t.Error("want panic")
+}
+
+func TestReadString_range(t *testing.T) {
+	defer func() { _ = recover() }()
+	mock := NewMockModule(128)
+	ReadString(mock, 130, math.MaxUint32)
+	t.Error("want panic")
+}

internal/util/mock.go

@@ -1,63 +1,54 @@
-package sqlite3
+package util
 
 import (
-	"context"
 	"encoding/binary"
 	"math"
 
 	"github.com/tetratelabs/wazero/api"
 )
 
-func init() {
-	Path = "./embed/sqlite3.wasm"
-}
-
-func newMemory(size uint32) memory {
-	mem := make(mockMemory, size)
-	return memory{mockModule{&mem}}
+func NewMockModule(size uint32) api.Module {
+	mem := mockMemory{buf: make([]byte, size)}
+	return mockModule{&mem, nil}
 }
 
 type mockModule struct {
 	memory api.Memory
+	api.Module
 }
 
 func (m mockModule) Memory() api.Memory { return m.memory }
 func (m mockModule) String() string     { return "mockModule" }
 func (m mockModule) Name() string       { return "mockModule" }
 
-func (m mockModule) ExportedGlobal(name string) api.Global                          { return nil }
-func (m mockModule) ExportedMemory(name string) api.Memory                          { return nil }
-func (m mockModule) ExportedFunction(name string) api.Function                      { return nil }
-func (m mockModule) ExportedMemoryDefinitions() map[string]api.MemoryDefinition     { return nil }
-func (m mockModule) ExportedFunctionDefinitions() map[string]api.FunctionDefinition { return nil }
-func (m mockModule) CloseWithExitCode(ctx context.Context, exitCode uint32) error   { return nil }
-func (m mockModule) Close(context.Context) error                                    { return nil }
-
-type mockMemory []byte
+type mockMemory struct {
+	buf []byte
+	api.Memory
+}
 
 func (m mockMemory) Definition() api.MemoryDefinition { return nil }
 
-func (m mockMemory) Size() uint32 { return uint32(len(m)) }
+func (m mockMemory) Size() uint32 { return uint32(len(m.buf)) }
 
 func (m mockMemory) ReadByte(offset uint32) (byte, bool) {
 	if offset >= m.Size() {
 		return 0, false
 	}
-	return m[offset], true
+	return m.buf[offset], true
 }
 
 func (m mockMemory) ReadUint16Le(offset uint32) (uint16, bool) {
 	if !m.hasSize(offset, 2) {
 		return 0, false
 	}
-	return binary.LittleEndian.Uint16(m[offset : offset+2]), true
+	return binary.LittleEndian.Uint16(m.buf[offset : offset+2]), true
 }
 
 func (m mockMemory) ReadUint32Le(offset uint32) (uint32, bool) {
 	if !m.hasSize(offset, 4) {
 		return 0, false
 	}
-	return binary.LittleEndian.Uint32(m[offset : offset+4]), true
+	return binary.LittleEndian.Uint32(m.buf[offset : offset+4]), true
 }
 
 func (m mockMemory) ReadFloat32Le(offset uint32) (float32, bool) {
@@ -72,7 +63,7 @@ func (m mockMemory) ReadUint64Le(offset uint32) (uint64, bool) {
 	if !m.hasSize(offset, 8) {
 		return 0, false
 	}
-	return binary.LittleEndian.Uint64(m[offset : offset+8]), true
+	return binary.LittleEndian.Uint64(m.buf[offset : offset+8]), true
 }
 
 func (m mockMemory) ReadFloat64Le(offset uint32) (float64, bool) {
@@ -87,14 +78,14 @@ func (m mockMemory) Read(offset, byteCount uint32) ([]byte, bool) {
 	if !m.hasSize(offset, byteCount) {
 		return nil, false
 	}
-	return m[offset : offset+byteCount : offset+byteCount], true
+	return m.buf[offset : offset+byteCount : offset+byteCount], true
 }
 
 func (m mockMemory) WriteByte(offset uint32, v byte) bool {
 	if offset >= m.Size() {
 		return false
 	}
-	m[offset] = v
+	m.buf[offset] = v
 	return true
 }
 
@@ -102,7 +93,7 @@ func (m mockMemory) WriteUint16Le(offset uint32, v uint16) bool {
 	if !m.hasSize(offset, 2) {
 		return false
 	}
-	binary.LittleEndian.PutUint16(m[offset:], v)
+	binary.LittleEndian.PutUint16(m.buf[offset:], v)
 	return true
 }
 
@@ -110,7 +101,7 @@ func (m mockMemory) WriteUint32Le(offset, v uint32) bool {
 	if !m.hasSize(offset, 4) {
 		return false
 	}
-	binary.LittleEndian.PutUint32(m[offset:], v)
+	binary.LittleEndian.PutUint32(m.buf[offset:], v)
 	return true
 }
 
@@ -122,7 +113,7 @@ func (m mockMemory) WriteUint64Le(offset uint32, v uint64) bool {
 	if !m.hasSize(offset, 8) {
 		return false
 	}
-	binary.LittleEndian.PutUint64(m[offset:], v)
+	binary.LittleEndian.PutUint64(m.buf[offset:], v)
 	return true
 }
 
@@ -134,7 +125,7 @@ func (m mockMemory) Write(offset uint32, val []byte) bool {
 	if !m.hasSize(offset, uint32(len(val))) {
 		return false
 	}
-	copy(m[offset:], val)
+	copy(m.buf[offset:], val)
 	return true
 }
 
@@ -142,20 +133,16 @@ func (m mockMemory) WriteString(offset uint32, val string) bool {
 	if !m.hasSize(offset, uint32(len(val))) {
 		return false
 	}
-	copy(m[offset:], val)
+	copy(m.buf[offset:], val)
 	return true
 }
 
 func (m *mockMemory) Grow(delta uint32) (result uint32, ok bool) {
-	prev := (len(*m) + 65535) / 65536
-	*m = append(*m, make([]byte, 65536*delta)...)
+	prev := (len(m.buf) + 65535) / 65536
+	m.buf = append(m.buf, make([]byte, 65536*delta)...)
 	return uint32(prev), true
 }
 
-func (m mockMemory) PageSize() (result uint32) {
-	return uint32(len(m) / 65536)
-}
-
 func (m mockMemory) hasSize(offset uint32, byteCount uint32) bool {
-	return uint64(offset)+uint64(byteCount) <= uint64(len(m))
+	return uint64(offset)+uint64(byteCount) <= uint64(len(m.buf))
 }

internal/util/mock_test.go

@@ -0,0 +1,242 @@
+package util
+
+import (
+	"math"
+	"testing"
+)
+
+func Test_mockMemory_byte(t *testing.T) {
+	const want byte = 98
+	mock := NewMockModule(128)
+
+	_, ok := mock.Memory().ReadByte(128)
+	if ok {
+		t.Error("want error")
+	}
+
+	ok = mock.Memory().WriteByte(128, 0)
+	if ok {
+		t.Error("want error")
+	}
+
+	ok = mock.Memory().WriteByte(0, want)
+	if !ok {
+		t.Error("want ok")
+	}
+
+	got, ok := mock.Memory().ReadByte(0)
+	if !ok {
+		t.Error("want ok")
+	}
+	if got != want {
+		t.Errorf("got %d, want %d", got, want)
+	}
+}
+
+func Test_mockMemory_uint16(t *testing.T) {
+	const want uint16 = 9876
+	mock := NewMockModule(128)
+
+	_, ok := mock.Memory().ReadUint16Le(128)
+	if ok {
+		t.Error("want error")
+	}
+
+	ok = mock.Memory().WriteUint16Le(128, 0)
+	if ok {
+		t.Error("want error")
+	}
+
+	ok = mock.Memory().WriteUint16Le(0, want)
+	if !ok {
+		t.Error("want ok")
+	}
+
+	got, ok := mock.Memory().ReadUint16Le(0)
+	if !ok {
+		t.Error("want ok")
+	}
+	if got != want {
+		t.Errorf("got %d, want %d", got, want)
+	}
+}
+
+func Test_mockMemory_uint32(t *testing.T) {
+	const want uint32 = 987654321
+	mock := NewMockModule(128)
+
+	_, ok := mock.Memory().ReadUint32Le(128)
+	if ok {
+		t.Error("want error")
+	}
+
+	ok = mock.Memory().WriteUint32Le(128, 0)
+	if ok {
+		t.Error("want error")
+	}
+
+	ok = mock.Memory().WriteUint32Le(0, want)
+	if !ok {
+		t.Error("want ok")
+	}
+
+	got, ok := mock.Memory().ReadUint32Le(0)
+	if !ok {
+		t.Error("want ok")
+	}
+	if got != want {
+		t.Errorf("got %d, want %d", got, want)
+	}
+}
+
+func Test_mockMemory_uint64(t *testing.T) {
+	const want uint64 = 9876543210
+	mock := NewMockModule(128)
+
+	_, ok := mock.Memory().ReadUint64Le(128)
+	if ok {
+		t.Error("want error")
+	}
+
+	ok = mock.Memory().WriteUint64Le(128, 0)
+	if ok {
+		t.Error("want error")
+	}
+
+	ok = mock.Memory().WriteUint64Le(0, want)
+	if !ok {
+		t.Error("want ok")
+	}
+
+	got, ok := mock.Memory().ReadUint64Le(0)
+	if !ok {
+		t.Error("want ok")
+	}
+	if got != want {
+		t.Errorf("got %d, want %d", got, want)
+	}
+}
+
+func Test_mockMemory_float32(t *testing.T) {
+	const want float32 = math.Pi
+	mock := NewMockModule(128)
+
+	_, ok := mock.Memory().ReadFloat32Le(128)
+	if ok {
+		t.Error("want error")
+	}
+
+	ok = mock.Memory().WriteFloat32Le(128, 0)
+	if ok {
+		t.Error("want error")
+	}
+
+	ok = mock.Memory().WriteFloat32Le(0, want)
+	if !ok {
+		t.Error("want ok")
+	}
+
+	got, ok := mock.Memory().ReadFloat32Le(0)
+	if !ok {
+		t.Error("want ok")
+	}
+	if got != want {
+		t.Errorf("got %f, want %f", got, want)
+	}
+}
+
+func Test_mockMemory_float64(t *testing.T) {
+	const want float64 = math.Pi
+	mock := NewMockModule(128)
+
+	_, ok := mock.Memory().ReadFloat64Le(128)
+	if ok {
+		t.Error("want error")
+	}
+
+	ok = mock.Memory().WriteFloat64Le(128, 0)
+	if ok {
+		t.Error("want error")
+	}
+
+	ok = mock.Memory().WriteFloat64Le(0, want)
+	if !ok {
+		t.Error("want ok")
+	}
+
+	got, ok := mock.Memory().ReadFloat64Le(0)
+	if !ok {
+		t.Error("want ok")
+	}
+	if got != want {
+		t.Errorf("got %f, want %f", got, want)
+	}
+}
+
+func Test_mockMemory_bytes(t *testing.T) {
+	const want string = "\xca\xfe\xba\xbe"
+	mock := NewMockModule(128)
+
+	_, ok := mock.Memory().Read(128, uint32(len(want)))
+	if ok {
+		t.Error("want error")
+	}
+
+	ok = mock.Memory().Write(128, []byte(want))
+	if ok {
+		t.Error("want error")
+	}
+
+	ok = mock.Memory().WriteString(128, want)
+	if ok {
+		t.Error("want error")
+	}
+
+	ok = mock.Memory().Write(0, []byte(want))
+	if !ok {
+		t.Error("want ok")
+	}
+
+	got, ok := mock.Memory().Read(0, uint32(len(want)))
+	if !ok {
+		t.Error("want ok")
+	}
+	if string(got) != want {
+		t.Errorf("got %q, want %q", got, want)
+	}
+
+	ok = mock.Memory().WriteString(64, want)
+	if !ok {
+		t.Error("want ok")
+	}
+
+	got, ok = mock.Memory().Read(64, uint32(len(want)))
+	if !ok {
+		t.Error("want ok")
+	}
+	if string(got) != want {
+		t.Errorf("got %q, want %q", got, want)
+	}
+}
+
+func Test_mockMemory_grow(t *testing.T) {
+	mock := NewMockModule(128)
+
+	_, ok := mock.Memory().ReadByte(65536)
+	if ok {
+		t.Error("want error")
+	}
+
+	got, ok := mock.Memory().Grow(1)
+	if !ok {
+		t.Error("want ok")
+	}
+	if got != 1 {
+		t.Errorf("got %d, want 1", got)
+	}
+
+	_, ok = mock.Memory().ReadByte(65536)
+	if !ok {
+		t.Error("want ok")
+	}
+}

mem.go

@@ -1,114 +0,0 @@
-package sqlite3
-
-import (
-	"bytes"
-	"math"
-
-	"github.com/tetratelabs/wazero/api"
-)
-
-type memory struct {
-	mod api.Module
-}
-
-func (m memory) view(ptr uint32, size uint64) []byte {
-	if ptr == 0 {
-		panic(nilErr)
-	}
-	if size > math.MaxUint32 {
-		panic(rangeErr)
-	}
-	buf, ok := m.mod.Memory().Read(ptr, uint32(size))
-	if !ok {
-		panic(rangeErr)
-	}
-	return buf
-}
-
-func (m memory) readUint32(ptr uint32) uint32 {
-	if ptr == 0 {
-		panic(nilErr)
-	}
-	v, ok := m.mod.Memory().ReadUint32Le(ptr)
-	if !ok {
-		panic(rangeErr)
-	}
-	return v
-}
-
-func (m memory) writeUint32(ptr, v uint32) {
-	if ptr == 0 {
-		panic(nilErr)
-	}
-	ok := m.mod.Memory().WriteUint32Le(ptr, v)
-	if !ok {
-		panic(rangeErr)
-	}
-}
-
-func (m memory) readUint64(ptr uint32) uint64 {
-	if ptr == 0 {
-		panic(nilErr)
-	}
-	v, ok := m.mod.Memory().ReadUint64Le(ptr)
-	if !ok {
-		panic(rangeErr)
-	}
-	return v
-}
-
-func (m memory) writeUint64(ptr uint32, v uint64) {
-	if ptr == 0 {
-		panic(nilErr)
-	}
-	ok := m.mod.Memory().WriteUint64Le(ptr, v)
-	if !ok {
-		panic(rangeErr)
-	}
-}
-
-func (m memory) readFloat64(ptr uint32) float64 {
-	return math.Float64frombits(m.readUint64(ptr))
-}
-
-func (m memory) writeFloat64(ptr uint32, v float64) {
-	m.writeUint64(ptr, math.Float64bits(v))
-}
-
-func (m memory) readString(ptr, maxlen uint32) string {
-	if ptr == 0 {
-		panic(nilErr)
-	}
-	switch maxlen {
-	case 0:
-		return ""
-	case math.MaxUint32:
-		// avoid overflow
-	default:
-		maxlen = maxlen + 1
-	}
-	mem := m.mod.Memory()
-	buf, ok := mem.Read(ptr, maxlen)
-	if !ok {
-		buf, ok = mem.Read(ptr, mem.Size()-ptr)
-		if !ok {
-			panic(rangeErr)
-		}
-	}
-	if i := bytes.IndexByte(buf, 0); i < 0 {
-		panic(noNulErr)
-	} else {
-		return string(buf[:i])
-	}
-}
-
-func (m memory) writeBytes(ptr uint32, b []byte) {
-	buf := m.view(ptr, uint64(len(b)))
-	copy(buf, b)
-}
-
-func (m memory) writeString(ptr uint32, s string) {
-	buf := m.view(ptr, uint64(len(s)+1))
-	buf[len(s)] = 0
-	copy(buf, s)
-}

mem_test.go

@@ -1,90 +0,0 @@
-package sqlite3
-
-import (
-	"math"
-	"testing"
-)
-
-func Test_memory_view_nil(t *testing.T) {
-	defer func() { _ = recover() }()
-	mem := newMemory(128)
-	mem.view(0, 8)
-	t.Error("want panic")
-}
-
-func Test_memory_view_range(t *testing.T) {
-	defer func() { _ = recover() }()
-	mem := newMemory(128)
-	mem.view(126, 8)
-	t.Error("want panic")
-}
-
-func Test_memory_view_overflow(t *testing.T) {
-	defer func() { _ = recover() }()
-	mem := newMemory(128)
-	mem.view(1, math.MaxInt64)
-	t.Error("want panic")
-}
-
-func Test_memory_readUint32_nil(t *testing.T) {
-	defer func() { _ = recover() }()
-	mem := newMemory(128)
-	mem.readUint32(0)
-	t.Error("want panic")
-}
-
-func Test_memory_readUint32_range(t *testing.T) {
-	defer func() { _ = recover() }()
-	mem := newMemory(128)
-	mem.readUint32(126)
-	t.Error("want panic")
-}
-
-func Test_memory_readUint64_nil(t *testing.T) {
-	defer func() { _ = recover() }()
-	mem := newMemory(128)
-	mem.readUint64(0)
-	t.Error("want panic")
-}
-
-func Test_memory_readUint64_range(t *testing.T) {
-	defer func() { _ = recover() }()
-	mem := newMemory(128)
-	mem.readUint64(126)
-	t.Error("want panic")
-}
-
-func Test_memory_writeUint32_nil(t *testing.T) {
-	defer func() { _ = recover() }()
-	mem := newMemory(128)
-	mem.writeUint32(0, 1)
-	t.Error("want panic")
-}
-
-func Test_memory_writeUint32_range(t *testing.T) {
-	defer func() { _ = recover() }()
-	mem := newMemory(128)
-	mem.writeUint32(126, 1)
-	t.Error("want panic")
-}
-
-func Test_memory_writeUint64_nil(t *testing.T) {
-	defer func() { _ = recover() }()
-	mem := newMemory(128)
-	mem.writeUint64(0, 1)
-	t.Error("want panic")
-}
-
-func Test_memory_writeUint64_range(t *testing.T) {
-	defer func() { _ = recover() }()
-	mem := newMemory(128)
-	mem.writeUint64(126, 1)
-	t.Error("want panic")
-}
-
-func Test_memory_readString_range(t *testing.T) {
-	defer func() { _ = recover() }()
-	mem := newMemory(128)
-	mem.readString(130, math.MaxUint32)
-	t.Error("want panic")
-}

module.go

@@ -0,0 +1,358 @@
+// Package sqlite3 wraps the C SQLite API.
+package sqlite3
+
+import (
+	"context"
+	"io"
+	"math"
+	"os"
+	"sync"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
+	"github.com/ncruces/go-sqlite3/sqlite3vfs"
+	"github.com/tetratelabs/wazero"
+	"github.com/tetratelabs/wazero/api"
+)
+
+// Configure SQLite WASM.
+//
+// Importing package embed initializes these
+// with an appropriate build of SQLite:
+//
+//	import _ "github.com/ncruces/go-sqlite3/embed"
+var (
+	Binary []byte // WASM binary to load.
+	Path   string // Path to load the binary from.
+)
+
+var sqlite3 struct {
+	runtime  wazero.Runtime
+	compiled wazero.CompiledModule
+	err      error
+	once     sync.Once
+}
+
+func instantiateModule() (*module, error) {
+	ctx := context.Background()
+
+	sqlite3.once.Do(compileModule)
+	if sqlite3.err != nil {
+		return nil, sqlite3.err
+	}
+
+	cfg := wazero.NewModuleConfig()
+
+	mod, err := sqlite3.runtime.InstantiateModule(ctx, sqlite3.compiled, cfg)
+	if err != nil {
+		return nil, err
+	}
+	return newModule(mod)
+}
+
+func compileModule() {
+	ctx := context.Background()
+	sqlite3.runtime = wazero.NewRuntime(ctx)
+
+	env := sqlite3vfs.ExportHostFunctions(sqlite3.runtime.NewHostModuleBuilder("env"))
+	_, sqlite3.err = env.Instantiate(ctx)
+	if sqlite3.err != nil {
+		return
+	}
+
+	bin := Binary
+	if bin == nil && Path != "" {
+		bin, sqlite3.err = os.ReadFile(Path)
+		if sqlite3.err != nil {
+			return
+		}
+	}
+	if bin == nil {
+		sqlite3.err = util.BinaryErr
+		return
+	}
+
+	sqlite3.compiled, sqlite3.err = sqlite3.runtime.CompileModule(ctx, bin)
+}
+
+type module struct {
+	ctx context.Context
+	mod api.Module
+	vfs io.Closer
+	api sqliteAPI
+	arg [8]uint64
+}
+
+func newModule(mod api.Module) (m *module, err error) {
+	m = &module{}
+	m.mod = mod
+	m.ctx, m.vfs = sqlite3vfs.NewContext(context.Background())
+
+	getFun := func(name string) api.Function {
+		f := mod.ExportedFunction(name)
+		if f == nil {
+			err = util.NoFuncErr + util.ErrorString(name)
+			return nil
+		}
+		return f
+	}
+
+	getVal := func(name string) uint32 {
+		g := mod.ExportedGlobal(name)
+		if g == nil {
+			err = util.NoGlobalErr + util.ErrorString(name)
+			return 0
+		}
+		return util.ReadUint32(mod, uint32(g.Get()))
+	}
+
+	m.api = sqliteAPI{
+		free:            getFun("free"),
+		malloc:          getFun("malloc"),
+		destructor:      getVal("malloc_destructor"),
+		errcode:         getFun("sqlite3_errcode"),
+		errstr:          getFun("sqlite3_errstr"),
+		errmsg:          getFun("sqlite3_errmsg"),
+		erroff:          getFun("sqlite3_error_offset"),
+		open:            getFun("sqlite3_open_v2"),
+		close:           getFun("sqlite3_close"),
+		closeZombie:     getFun("sqlite3_close_v2"),
+		prepare:         getFun("sqlite3_prepare_v3"),
+		finalize:        getFun("sqlite3_finalize"),
+		reset:           getFun("sqlite3_reset"),
+		step:            getFun("sqlite3_step"),
+		exec:            getFun("sqlite3_exec"),
+		clearBindings:   getFun("sqlite3_clear_bindings"),
+		bindCount:       getFun("sqlite3_bind_parameter_count"),
+		bindIndex:       getFun("sqlite3_bind_parameter_index"),
+		bindName:        getFun("sqlite3_bind_parameter_name"),
+		bindNull:        getFun("sqlite3_bind_null"),
+		bindInteger:     getFun("sqlite3_bind_int64"),
+		bindFloat:       getFun("sqlite3_bind_double"),
+		bindText:        getFun("sqlite3_bind_text64"),
+		bindBlob:        getFun("sqlite3_bind_blob64"),
+		bindZeroBlob:    getFun("sqlite3_bind_zeroblob64"),
+		columnCount:     getFun("sqlite3_column_count"),
+		columnName:      getFun("sqlite3_column_name"),
+		columnType:      getFun("sqlite3_column_type"),
+		columnInteger:   getFun("sqlite3_column_int64"),
+		columnFloat:     getFun("sqlite3_column_double"),
+		columnText:      getFun("sqlite3_column_text"),
+		columnBlob:      getFun("sqlite3_column_blob"),
+		columnBytes:     getFun("sqlite3_column_bytes"),
+		autocommit:      getFun("sqlite3_get_autocommit"),
+		lastRowid:       getFun("sqlite3_last_insert_rowid"),
+		changes:         getFun("sqlite3_changes64"),
+		blobOpen:        getFun("sqlite3_blob_open"),
+		blobClose:       getFun("sqlite3_blob_close"),
+		blobReopen:      getFun("sqlite3_blob_reopen"),
+		blobBytes:       getFun("sqlite3_blob_bytes"),
+		blobRead:        getFun("sqlite3_blob_read"),
+		blobWrite:       getFun("sqlite3_blob_write"),
+		backupInit:      getFun("sqlite3_backup_init"),
+		backupStep:      getFun("sqlite3_backup_step"),
+		backupFinish:    getFun("sqlite3_backup_finish"),
+		backupRemaining: getFun("sqlite3_backup_remaining"),
+		backupPageCount: getFun("sqlite3_backup_pagecount"),
+	}
+	if err != nil {
+		return nil, err
+	}
+	return m, nil
+}
+
+func (m *module) close() error {
+	err := m.mod.Close(m.ctx)
+	m.vfs.Close()
+	return err
+}
+
+func (m *module) error(rc uint64, handle uint32, sql ...string) error {
+	if rc == _OK {
+		return nil
+	}
+
+	err := Error{code: rc}
+
+	if err.Code() == NOMEM || err.ExtendedCode() == IOERR_NOMEM {
+		panic(util.OOMErr)
+	}
+
+	var r []uint64
+
+	r = m.call(m.api.errstr, rc)
+	if r != nil {
+		err.str = util.ReadString(m.mod, uint32(r[0]), _MAX_STRING)
+	}
+
+	r = m.call(m.api.errmsg, uint64(handle))
+	if r != nil {
+		err.msg = util.ReadString(m.mod, uint32(r[0]), _MAX_STRING)
+	}
+
+	if sql != nil {
+		r = m.call(m.api.erroff, uint64(handle))
+		if r != nil && r[0] != math.MaxUint32 {
+			err.sql = sql[0][r[0]:]
+		}
+	}
+
+	switch err.msg {
+	case err.str, "not an error":
+		err.msg = ""
+	}
+	return &err
+}
+
+func (m *module) call(fn api.Function, params ...uint64) []uint64 {
+	copy(m.arg[:], params)
+	err := fn.CallWithStack(m.ctx, m.arg[:])
+	if err != nil {
+		// The module closed or panicked; release resources.
+		m.vfs.Close()
+		panic(err)
+	}
+	return m.arg[:]
+}
+
+func (m *module) free(ptr uint32) {
+	if ptr == 0 {
+		return
+	}
+	m.call(m.api.free, uint64(ptr))
+}
+
+func (m *module) new(size uint64) uint32 {
+	if size > _MAX_ALLOCATION_SIZE {
+		panic(util.OOMErr)
+	}
+	r := m.call(m.api.malloc, size)
+	ptr := uint32(r[0])
+	if ptr == 0 && size != 0 {
+		panic(util.OOMErr)
+	}
+	return ptr
+}
+
+func (m *module) newBytes(b []byte) uint32 {
+	if b == nil {
+		return 0
+	}
+	ptr := m.new(uint64(len(b)))
+	util.WriteBytes(m.mod, ptr, b)
+	return ptr
+}
+
+func (m *module) newString(s string) uint32 {
+	ptr := m.new(uint64(len(s) + 1))
+	util.WriteString(m.mod, ptr, s)
+	return ptr
+}
+
+func (m *module) newArena(size uint64) arena {
+	return arena{
+		m:    m,
+		base: m.new(size),
+		size: uint32(size),
+	}
+}
+
+type arena struct {
+	m    *module
+	ptrs []uint32
+	base uint32
+	next uint32
+	size uint32
+}
+
+func (a *arena) free() {
+	if a.m == nil {
+		return
+	}
+	a.reset()
+	a.m.free(a.base)
+	a.m = nil
+}
+
+func (a *arena) reset() {
+	for _, ptr := range a.ptrs {
+		a.m.free(ptr)
+	}
+	a.ptrs = nil
+	a.next = 0
+}
+
+func (a *arena) new(size uint64) uint32 {
+	if size <= uint64(a.size-a.next) {
+		ptr := a.base + a.next
+		a.next += uint32(size)
+		return ptr
+	}
+	ptr := a.m.new(size)
+	a.ptrs = append(a.ptrs, ptr)
+	return ptr
+}
+
+func (a *arena) bytes(b []byte) uint32 {
+	if b == nil {
+		return 0
+	}
+	ptr := a.new(uint64(len(b)))
+	util.WriteBytes(a.m.mod, ptr, b)
+	return ptr
+}
+
+func (a *arena) string(s string) uint32 {
+	ptr := a.new(uint64(len(s) + 1))
+	util.WriteString(a.m.mod, ptr, s)
+	return ptr
+}
+
+type sqliteAPI struct {
+	free            api.Function
+	malloc          api.Function
+	errcode         api.Function
+	errstr          api.Function
+	errmsg          api.Function
+	erroff          api.Function
+	open            api.Function
+	close           api.Function
+	closeZombie     api.Function
+	prepare         api.Function
+	finalize        api.Function
+	reset           api.Function
+	step            api.Function
+	exec            api.Function
+	clearBindings   api.Function
+	bindNull        api.Function
+	bindCount       api.Function
+	bindIndex       api.Function
+	bindName        api.Function
+	bindInteger     api.Function
+	bindFloat       api.Function
+	bindText        api.Function
+	bindBlob        api.Function
+	bindZeroBlob    api.Function
+	columnCount     api.Function
+	columnName      api.Function
+	columnType      api.Function
+	columnInteger   api.Function
+	columnFloat     api.Function
+	columnText      api.Function
+	columnBlob      api.Function
+	columnBytes     api.Function
+	autocommit      api.Function
+	lastRowid       api.Function
+	changes         api.Function
+	blobOpen        api.Function
+	blobClose       api.Function
+	blobReopen      api.Function
+	blobBytes       api.Function
+	blobRead        api.Function
+	blobWrite       api.Function
+	backupInit      api.Function
+	backupStep      api.Function
+	backupFinish    api.Function
+	backupRemaining api.Function
+	backupPageCount api.Function
+	destructor      uint32
+}

module_test.go

@@ -4,65 +4,75 @@ import (
 	"bytes"
 	"math"
 	"testing"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
 )
 
+func init() {
+	Path = "./embed/sqlite3.wasm"
+}
+
 func TestConn_error_OOM(t *testing.T) {
 	t.Parallel()
 
-	db, err := Open(":memory:")
+	m, err := instantiateModule()
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer db.Close()
+	defer m.close()
 
 	defer func() { _ = recover() }()
-	db.error(uint64(NOMEM))
+	m.error(uint64(NOMEM), 0)
 	t.Error("want panic")
 }
 
-func TestConn_call_nil(t *testing.T) {
+func TestConn_call_closed(t *testing.T) {
 	t.Parallel()
 
-	db, err := Open(":memory:")
+	m, err := instantiateModule()
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer db.Close()
+	m.close()
 
 	defer func() { _ = recover() }()
-	db.call(db.api.free)
+	m.call(m.api.free)
 	t.Error("want panic")
 }
 
 func TestConn_new(t *testing.T) {
 	t.Parallel()
 
-	db, err := Open(":memory:")
+	m, err := instantiateModule()
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer db.Close()
+	defer m.close()
 
-	testOOM := func(size uint64) {
+	t.Run("MaxUint32", func(t *testing.T) {
 		defer func() { _ = recover() }()
-		db.new(size)
+		m.new(math.MaxUint32)
 		t.Error("want panic")
-	}
+	})
 
-	testOOM(math.MaxUint32)
-	testOOM(_MAX_ALLOCATION_SIZE)
+	t.Run("_MAX_ALLOCATION_SIZE", func(t *testing.T) {
+		defer func() { _ = recover() }()
+		m.new(_MAX_ALLOCATION_SIZE)
+		m.new(_MAX_ALLOCATION_SIZE)
+		t.Error("want panic")
+	})
 }
 
 func TestConn_newArena(t *testing.T) {
 	t.Parallel()
 
-	db, err := Open(":memory:")
+	m, err := instantiateModule()
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer db.Close()
+	defer m.close()
 
-	arena := db.newArena(16)
+	arena := m.newArena(16)
 	defer arena.free()
 
 	const title = "Lorem ipsum"
@@ -71,7 +81,7 @@ func TestConn_newArena(t *testing.T) {
 	if ptr == 0 {
 		t.Fatalf("got nullptr")
 	}
-	if got := db.mem.readString(ptr, math.MaxUint32); got != title {
+	if got := util.ReadString(m.mod, ptr, math.MaxUint32); got != title {
 		t.Errorf("got %q, want %q", got, title)
 	}
 
@@ -80,7 +90,7 @@ func TestConn_newArena(t *testing.T) {
 	if ptr == 0 {
 		t.Fatalf("got nullptr")
 	}
-	if got := db.mem.readString(ptr, math.MaxUint32); got != body {
+	if got := util.ReadString(m.mod, ptr, math.MaxUint32); got != body {
 		t.Errorf("got %q, want %q", got, body)
 	}
 	arena.free()
@@ -89,25 +99,25 @@ func TestConn_newArena(t *testing.T) {
 func TestConn_newBytes(t *testing.T) {
 	t.Parallel()
 
-	db, err := Open(":memory:")
+	m, err := instantiateModule()
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer db.Close()
+	defer m.close()
 
-	ptr := db.newBytes(nil)
+	ptr := m.newBytes(nil)
 	if ptr != 0 {
 		t.Errorf("got %#x, want nullptr", ptr)
 	}
 
 	buf := []byte("sqlite3")
-	ptr = db.newBytes(buf)
+	ptr = m.newBytes(buf)
 	if ptr == 0 {
 		t.Fatal("got nullptr, want a pointer")
 	}
 
 	want := buf
-	if got := db.mem.view(ptr, uint64(len(want))); !bytes.Equal(got, want) {
+	if got := util.View(m.mod, ptr, uint64(len(want))); !bytes.Equal(got, want) {
 		t.Errorf("got %q, want %q", got, want)
 	}
 }
@@ -115,25 +125,25 @@ func TestConn_newBytes(t *testing.T) {
 func TestConn_newString(t *testing.T) {
 	t.Parallel()
 
-	db, err := Open(":memory:")
+	m, err := instantiateModule()
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer db.Close()
+	defer m.close()
 
-	ptr := db.newString("")
+	ptr := m.newString("")
 	if ptr == 0 {
 		t.Error("got nullptr, want a pointer")
 	}
 
 	str := "sqlite3\000sqlite3"
-	ptr = db.newString(str)
+	ptr = m.newString(str)
 	if ptr == 0 {
 		t.Fatal("got nullptr, want a pointer")
 	}
 
 	want := str + "\000"
-	if got := db.mem.view(ptr, uint64(len(want))); string(got) != want {
+	if got := util.View(m.mod, ptr, uint64(len(want))); string(got) != want {
 		t.Errorf("got %q, want %q", got, want)
 	}
 }
@@ -141,40 +151,40 @@ func TestConn_newString(t *testing.T) {
 func TestConn_getString(t *testing.T) {
 	t.Parallel()
 
-	db, err := Open(":memory:")
+	m, err := instantiateModule()
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer db.Close()
+	defer m.close()
 
-	ptr := db.newString("")
+	ptr := m.newString("")
 	if ptr == 0 {
 		t.Error("got nullptr, want a pointer")
 	}
 
 	str := "sqlite3" + "\000 drop this"
-	ptr = db.newString(str)
+	ptr = m.newString(str)
 	if ptr == 0 {
 		t.Fatal("got nullptr, want a pointer")
 	}
 
 	want := "sqlite3"
-	if got := db.mem.readString(ptr, math.MaxUint32); got != want {
+	if got := util.ReadString(m.mod, ptr, math.MaxUint32); got != want {
 		t.Errorf("got %q, want %q", got, want)
 	}
-	if got := db.mem.readString(ptr, 0); got != "" {
+	if got := util.ReadString(m.mod, ptr, 0); got != "" {
 		t.Errorf("got %q, want empty", got)
 	}
 
 	func() {
 		defer func() { _ = recover() }()
-		db.mem.readString(ptr, uint32(len(want)/2))
+		util.ReadString(m.mod, ptr, uint32(len(want)/2))
 		t.Error("want panic")
 	}()
 
 	func() {
 		defer func() { _ = recover() }()
-		db.mem.readString(0, math.MaxUint32)
+		util.ReadString(m.mod, 0, math.MaxUint32)
 		t.Error("want panic")
 	}()
 }
@@ -182,18 +192,18 @@ func TestConn_getString(t *testing.T) {
 func TestConn_free(t *testing.T) {
 	t.Parallel()
 
-	db, err := Open(":memory:")
+	m, err := instantiateModule()
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer db.Close()
+	defer m.close()
 
-	db.free(0)
+	m.free(0)
 
-	ptr := db.new(1)
+	ptr := m.new(1)
 	if ptr == 0 {
 		t.Error("got nullptr, want a pointer")
 	}
 
-	db.free(ptr)
+	m.free(ptr)
 }

sqlite3/.gitignore

@@ -0,0 +1,3 @@
+sqlite3.c
+sqlite3.h
+sqlite3ext.h

sqlite3/amalg.c

@@ -1,9 +0,0 @@
-#include <stddef.h>
-
-#include "main.c"
-#include "os.c"
-#include "qsort.c"
-#include "sqlite3.c"
-
-sqlite3_destructor_type malloc_destructor = &free;
-size_t sqlite3_interrupt_offset = offsetof(sqlite3, u1.isInterrupted);

sqlite3/download.sh

@@ -1,13 +1,31 @@
 #!/usr/bin/env bash
-set -eo pipefail
+set -euo pipefail
 
 cd -P -- "$(dirname -- "$0")"
 
-if [ ! -f "sqlite3.c" ]; then
-	url="https://sqlite.org/2023/sqlite-amalgamation-3410000.zip"
-	curl "$url" > sqlite.zip
-	unzip -d . sqlite.zip
-	mv sqlite-amalgamation-*/sqlite3* .
-	rm -rf sqlite-amalgamation-*
-	rm sqlite.zip
-fi
+curl -#OL "https://sqlite.org/2023/sqlite-amalgamation-3420000.zip"
+unzip -d . sqlite-amalgamation-*.zip
+mv sqlite-amalgamation-*/sqlite3* .
+rm -rf sqlite-amalgamation-*
+
+cd ext/
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.42.0/ext/misc/decimal.c"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.42.0/ext/misc/uint.c"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.42.0/ext/misc/uuid.c"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.42.0/ext/misc/base64.c"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.42.0/ext/misc/regexp.c"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.42.0/ext/misc/series.c"
+cd ~-
+
+cd ../sqlite3vfs/tests/mptest/testdata/
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.42.0/mptest/mptest.c"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.42.0/mptest/config01.test"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.42.0/mptest/config02.test"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.42.0/mptest/crash01.test"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.42.0/mptest/crash02.subtest"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.42.0/mptest/multiwrite01.test"
+cd ~-
+
+cd ../sqlite3vfs/tests/speedtest1/testdata/
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.42.0/test/speedtest1.c"
+cd ~-

sqlite3/ext/.gitignore

@@ -0,0 +1 @@
+*.c

sqlite3/format.sh

@@ -1,8 +1,7 @@
 #!/usr/bin/env bash
+set -euo pipefail
+
 cd -P -- "$(dirname -- "$0")"
 
-clang-format -i \
-	main.c \
-	os.c \
-	qsort.c \
-	amalg.c
+shopt -s extglob
+clang-format -i !(sqlite3*).@(c|h)

sqlite3/main.c

@@ -1,14 +1,28 @@
 #include <stdbool.h>
+#include <stddef.h>
 
-#include "sqlite3.h"
+// Configuration
+#include "sqlite_cfg.h"
+// Amalgamation
+#include "sqlite3.c"
+// VFS
+#include "vfs.c"
+// Extensions
+#include "ext/base64.c"
+#include "ext/decimal.c"
+#include "ext/regexp.c"
+#include "ext/series.c"
+#include "ext/uint.c"
+#include "ext/uuid.c"
+#include "time.c"
 
-int main() {
-  int rc = sqlite3_initialize();
-  if (rc != SQLITE_OK) return 1;
-}
-
-sqlite3_vfs *os_vfs();
-
-int sqlite3_os_init() {
-  return sqlite3_vfs_register(os_vfs(), /*default=*/true);
+__attribute__((constructor)) void init() {
+  sqlite3_initialize();
+  sqlite3_auto_extension((void (*)(void))sqlite3_base_init);
+  sqlite3_auto_extension((void (*)(void))sqlite3_decimal_init);
+  sqlite3_auto_extension((void (*)(void))sqlite3_regexp_init);
+  sqlite3_auto_extension((void (*)(void))sqlite3_series_init);
+  sqlite3_auto_extension((void (*)(void))sqlite3_uint_init);
+  sqlite3_auto_extension((void (*)(void))sqlite3_uuid_init);
+  sqlite3_auto_extension((void (*)(void))sqlite3_time_init);
 }

sqlite3/os.c

@@ -1,92 +0,0 @@
-#include <time.h>
-
-#include "sqlite3.h"
-
-int os_localtime(sqlite3_int64, struct tm *);
-
-int os_randomness(sqlite3_vfs *, int nByte, char *zOut);
-int os_sleep(sqlite3_vfs *, int microseconds);
-int os_current_time(sqlite3_vfs *, double *);
-int os_current_time_64(sqlite3_vfs *, sqlite3_int64 *);
-
-int os_open(sqlite3_vfs *, sqlite3_filename zName, sqlite3_file *, int flags,
-            int *pOutFlags);
-int os_delete(sqlite3_vfs *, const char *zName, int syncDir);
-int os_access(sqlite3_vfs *, const char *zName, int flags, int *pResOut);
-int os_full_pathname(sqlite3_vfs *, const char *zName, int nOut, char *zOut);
-
-struct os_file {
-  sqlite3_file base;
-  int id;
-  int lock;
-};
-
-int os_close(sqlite3_file *);
-int os_read(sqlite3_file *, void *, int iAmt, sqlite3_int64 iOfst);
-int os_write(sqlite3_file *, const void *, int iAmt, sqlite3_int64 iOfst);
-int os_truncate(sqlite3_file *, sqlite3_int64 size);
-int os_sync(sqlite3_file *, int flags);
-int os_file_size(sqlite3_file *, sqlite3_int64 *pSize);
-int os_file_control(sqlite3_file *pFile, int op, void *pArg);
-
-int os_lock(sqlite3_file *pFile, int eLock);
-int os_unlock(sqlite3_file *pFile, int eLock);
-int os_check_reserved_lock(sqlite3_file *pFile, int *pResOut);
-
-static int no_lock(sqlite3_file *pFile, int eLock) { return SQLITE_OK; }
-static int no_unlock(sqlite3_file *pFile, int eLock) { return SQLITE_OK; }
-static int no_check_reserved_lock(sqlite3_file *pFile, int *pResOut) {
-  *pResOut = 0;
-  return SQLITE_OK;
-}
-
-static int no_file_control(sqlite3_file *pFile, int op, void *pArg) {
-  return SQLITE_NOTFOUND;
-}
-static int no_sector_size(sqlite3_file *pFile) { return 0; }
-static int no_device_characteristics(sqlite3_file *pFile) { return 0; }
-
-int localtime_s(struct tm *const pTm, time_t const *const pTime) {
-  return os_localtime((sqlite3_int64)*pTime, pTm);
-}
-
-static int os_open_w(sqlite3_vfs *vfs, sqlite3_filename zName,
-                     sqlite3_file *file, int flags, int *pOutFlags) {
-  static const sqlite3_io_methods os_io = {
-      .iVersion = 1,
-      .xClose = os_close,
-      .xRead = os_read,
-      .xWrite = os_write,
-      .xTruncate = os_truncate,
-      .xSync = os_sync,
-      .xFileSize = os_file_size,
-      .xLock = os_lock,
-      .xUnlock = os_unlock,
-      .xCheckReservedLock = os_check_reserved_lock,
-      .xFileControl = no_file_control,
-      .xDeviceCharacteristics = no_device_characteristics,
-  };
-  int rc = os_open(vfs, zName, file, flags, pOutFlags);
-  file->pMethods = (char)rc == SQLITE_OK ? &os_io : NULL;
-  return rc;
-}
-
-sqlite3_vfs *os_vfs() {
-  static sqlite3_vfs os_vfs = {
-      .iVersion = 2,
-      .szOsFile = sizeof(struct os_file),
-      .mxPathname = 512,
-      .zName = "os",
-
-      .xOpen = os_open_w,
-      .xDelete = os_delete,
-      .xAccess = os_access,
-      .xFullPathname = os_full_pathname,
-
-      .xRandomness = os_randomness,
-      .xSleep = os_sleep,
-      .xCurrentTime = os_current_time,
-      .xCurrentTimeInt64 = os_current_time_64,
-  };
-  return &os_vfs;
-}

sqlite3/qsort.c

@@ -1,14 +0,0 @@
-#include <stddef.h>
-
-void qsort_r(void *, size_t, size_t,
-             int (*)(const void *, const void *, void *), void *);
-
-typedef int (*cmpfun)(const void *, const void *);
-
-static int wrapper_cmp(const void *v1, const void *v2, void *cmp) {
-  return ((cmpfun)cmp)(v1, v2);
-}
-
-void qsort(void *base, size_t nel, size_t width, cmpfun cmp) {
-  qsort_r(base, nel, width, wrapper_cmp, cmp);
-}

sqlite3/sqlite_cfg.h

@@ -28,14 +28,19 @@
 #define SQLITE_OMIT_AUTOINIT
 #define SQLITE_USE_ALLOCA
 
+// Other Options
+#define SQLITE_ALLOW_URI_AUTHORITY
+
 // Because WASM does not support shared memory,
-// SQLite disables it for WASM builds.
+// SQLite disables WAL for WASM builds.
 // We set the default locking mode to EXCLUSIVE instead.
 // https://www.sqlite.org/wal.html#noshm
 #undef SQLITE_OMIT_WAL
+#ifndef SQLITE_DEFAULT_LOCKING_MODE
 #define SQLITE_DEFAULT_LOCKING_MODE 1
+#endif
 
-// Recommended Extensions
+// Amalgamated Extensions
 
 #define SQLITE_ENABLE_MATH_FUNCTIONS 1
 #define SQLITE_ENABLE_JSON1 1
@@ -46,15 +51,20 @@
 #define SQLITE_ENABLE_RTREE 1
 #define SQLITE_ENABLE_GEOPOLY 1
 
-// Snapshot
-// #define SQLITE_ENABLE_SNAPSHOT 1
-
 // Session Extension
-// #define SQLITE_ENABLE_SESSION 1
-// #define SQLITE_ENABLE_PREUPDATE_HOOK 1
+// #define SQLITE_ENABLE_SESSION
+// #define SQLITE_ENABLE_PREUPDATE_HOOK
 
-// Resumable Bulk Update Extension
-// #define SQLITE_ENABLE_RBU 1
+// https://stackoverflow.com/a/50616684
+#define SECOND(...) SECOND_I(__VA_ARGS__, , )
+#define SECOND_I(A, B, ...) B
+#define GLUE(A, B) GLUE_I(A, B)
+#define GLUE_I(A, B) A##_##B
+#define CREATE_REPLACER(A) SECOND(GLUE(A, __LINE__), A)
+#define REPLACE_AT_LINE(A) , A
 
-// Implemented in Go.
-int localtime_s(struct tm *const pTm, time_t const *const pTime);
+// Implemented in vfs.c.
+int localtime_s(struct tm *const pTm, time_t const *const pTime);
+
+#define sqlite3_vfs_find CREATE_REPLACER(sqlite3_vfs_find_wrapper)
+#define sqlite3_vfs_find_wrapper_25397 REPLACE_AT_LINE(sqlite3_vfs_find)

sqlite3/time.c

@@ -0,0 +1,32 @@
+#include <string.h>
+
+#include "sqlite3.h"
+
+static int time_collation(void *pArg, int nKey1, const void *pKey1, int nKey2,
+                          const void *pKey2) {
+  // Remove a Z suffix if one key is no longer than the other.
+  // A Z suffix collates before any character but after the empty string.
+  // This avoids making different keys equal.
+  const int nK1 = nKey1;
+  const int nK2 = nKey2;
+  const char *pK1 = (const char *)pKey1;
+  const char *pK2 = (const char *)pKey2;
+  if (nK1 && nK1 <= nK2 && pK1[nK1 - 1] == 'Z') {
+    nKey1--;
+  }
+  if (nK2 && nK2 <= nK1 && pK2[nK2 - 1] == 'Z') {
+    nKey2--;
+  }
+
+  int n = nKey1 < nKey2 ? nKey1 : nKey2;
+  int rc = memcmp(pKey1, pKey2, n);
+  if (rc == 0) {
+    rc = nKey1 - nKey2;
+  }
+  return rc;
+}
+
+int sqlite3_time_init(sqlite3 *db, char **pzErrMsg,
+                      const sqlite3_api_routines *pApi) {
+  return sqlite3_create_collation(db, "time", SQLITE_UTF8, 0, time_collation);
+}

sqlite3/vfs.c

@@ -0,0 +1,138 @@
+#include <time.h>
+
+#include "sqlite3.h"
+
+int go_localtime(struct tm *, sqlite3_int64);
+int go_vfs_find(const char *zVfsName);
+
+int go_randomness(sqlite3_vfs *, int nByte, char *zOut);
+int go_sleep(sqlite3_vfs *, int microseconds);
+int go_current_time(sqlite3_vfs *, double *);
+int go_current_time_64(sqlite3_vfs *, sqlite3_int64 *);
+
+int go_open(sqlite3_vfs *, sqlite3_filename zName, sqlite3_file *, int flags,
+            int *pOutFlags);
+int go_delete(sqlite3_vfs *, const char *zName, int syncDir);
+int go_access(sqlite3_vfs *, const char *zName, int flags, int *pResOut);
+int go_full_pathname(sqlite3_vfs *, const char *zName, int nOut, char *zOut);
+
+int go_close(sqlite3_file *);
+int go_read(sqlite3_file *, void *, int iAmt, sqlite3_int64 iOfst);
+int go_write(sqlite3_file *, const void *, int iAmt, sqlite3_int64 iOfst);
+int go_truncate(sqlite3_file *, sqlite3_int64 size);
+int go_sync(sqlite3_file *, int flags);
+int go_file_size(sqlite3_file *, sqlite3_int64 *pSize);
+int go_file_control(sqlite3_file *, int op, void *pArg);
+int go_sector_size(sqlite3_file *file);
+int go_device_characteristics(sqlite3_file *file);
+
+int go_lock(sqlite3_file *, int eLock);
+int go_unlock(sqlite3_file *, int eLock);
+int go_check_reserved_lock(sqlite3_file *, int *pResOut);
+
+static int go_open_wrapper(sqlite3_vfs *vfs, sqlite3_filename zName,
+                           sqlite3_file *file, int flags, int *pOutFlags) {
+  static const sqlite3_io_methods os_io = {
+      .iVersion = 1,
+      .xClose = go_close,
+      .xRead = go_read,
+      .xWrite = go_write,
+      .xTruncate = go_truncate,
+      .xSync = go_sync,
+      .xFileSize = go_file_size,
+      .xLock = go_lock,
+      .xUnlock = go_unlock,
+      .xCheckReservedLock = go_check_reserved_lock,
+      .xFileControl = go_file_control,
+      .xSectorSize = go_sector_size,
+      .xDeviceCharacteristics = go_device_characteristics,
+  };
+  memset(file, 0, vfs->szOsFile);
+  int rc = go_open(vfs, zName, file, flags, pOutFlags);
+  if (rc) {
+    return rc;
+  }
+  file->pMethods = &os_io;
+  return SQLITE_OK;
+}
+
+struct go_file {
+  sqlite3_file base;
+  int handle;
+};
+
+int sqlite3_os_init() {
+  static sqlite3_vfs os_vfs = {
+      .iVersion = 2,
+      .szOsFile = sizeof(struct go_file),
+      .mxPathname = 512,
+      .zName = "os",
+
+      .xOpen = go_open_wrapper,
+      .xDelete = go_delete,
+      .xAccess = go_access,
+      .xFullPathname = go_full_pathname,
+
+      .xRandomness = go_randomness,
+      .xSleep = go_sleep,
+      .xCurrentTime = go_current_time,
+      .xCurrentTimeInt64 = go_current_time_64,
+  };
+  return sqlite3_vfs_register(&os_vfs, /*default=*/true);
+}
+
+sqlite3_destructor_type malloc_destructor = &free;
+
+int localtime_s(struct tm *const pTm, time_t const *const pTime) {
+  return go_localtime(pTm, (sqlite3_int64)*pTime);
+}
+
+#undef sqlite3_vfs_find
+sqlite3_vfs *sqlite3_vfs_find_wrapper(const char *zVfsName) {
+  if (zVfsName) {
+    static sqlite3_vfs *go_vfs_list;
+    sqlite3_vfs *found = NULL;
+    for (sqlite3_vfs **next = &go_vfs_list; *next;) {
+      sqlite3_vfs *it = *next;
+      if (go_vfs_find(it->zName)) {
+        if (!strcmp(zVfsName, it->zName)) found = it;
+        next = &it->pNext;
+      } else {
+        *next = it->pNext;
+        free(it);
+      }
+    }
+    if (found) {
+      return found;
+    }
+    if (go_vfs_find(zVfsName)) {
+      sqlite3_vfs *prev = go_vfs_list;
+      go_vfs_list = malloc(sizeof(sqlite3_vfs) + strlen(zVfsName) + 1);
+      char *name = (char *)(go_vfs_list + 1);
+      strcpy(name, zVfsName);
+      *go_vfs_list = (sqlite3_vfs){
+          .iVersion = 2,
+          .szOsFile = sizeof(struct go_file),
+          .mxPathname = 512,
+          .zName = name,
+          .pNext = prev,
+
+          .xOpen = go_open_wrapper,
+          .xDelete = go_delete,
+          .xAccess = go_access,
+          .xFullPathname = go_full_pathname,
+
+          .xRandomness = go_randomness,
+          .xSleep = go_sleep,
+          .xCurrentTime = go_current_time,
+          .xCurrentTimeInt64 = go_current_time_64,
+      };
+      return go_vfs_list;
+    }
+  }
+  return sqlite3_vfs_find(zVfsName);
+}
+
+static_assert(offsetof(struct go_file, handle) == 4, "Unexpected offset");
+static_assert(offsetof(sqlite3_vfs, zName) == 16, "Unexpected offset");
+static_assert(offsetof(sqlite3, u1.isInterrupted) == 280, "Unexpected offset");

sqlite3vfs/const.go

@@ -0,0 +1,210 @@
+package sqlite3vfs
+
+import "github.com/ncruces/go-sqlite3/internal/util"
+
+const (
+	_MAX_STRING          = 512 // Used for short strings: names, error messages…
+	_MAX_PATHNAME        = 512
+	_DEFAULT_SECTOR_SIZE = 4096
+)
+
+// https://www.sqlite.org/rescode.html
+type _ErrorCode uint32
+
+func (e _ErrorCode) Error() string {
+	return util.ErrorCodeString(uint32(e))
+}
+
+const (
+	_OK                      _ErrorCode = util.OK
+	_PERM                    _ErrorCode = util.PERM
+	_BUSY                    _ErrorCode = util.BUSY
+	_IOERR                   _ErrorCode = util.IOERR
+	_NOTFOUND                _ErrorCode = util.NOTFOUND
+	_CANTOPEN                _ErrorCode = util.CANTOPEN
+	_IOERR_READ              _ErrorCode = util.IOERR_READ
+	_IOERR_SHORT_READ        _ErrorCode = util.IOERR_SHORT_READ
+	_IOERR_WRITE             _ErrorCode = util.IOERR_WRITE
+	_IOERR_FSYNC             _ErrorCode = util.IOERR_FSYNC
+	_IOERR_DIR_FSYNC         _ErrorCode = util.IOERR_DIR_FSYNC
+	_IOERR_TRUNCATE          _ErrorCode = util.IOERR_TRUNCATE
+	_IOERR_FSTAT             _ErrorCode = util.IOERR_FSTAT
+	_IOERR_UNLOCK            _ErrorCode = util.IOERR_UNLOCK
+	_IOERR_RDLOCK            _ErrorCode = util.IOERR_RDLOCK
+	_IOERR_DELETE            _ErrorCode = util.IOERR_DELETE
+	_IOERR_ACCESS            _ErrorCode = util.IOERR_ACCESS
+	_IOERR_CHECKRESERVEDLOCK _ErrorCode = util.IOERR_CHECKRESERVEDLOCK
+	_IOERR_LOCK              _ErrorCode = util.IOERR_LOCK
+	_IOERR_CLOSE             _ErrorCode = util.IOERR_CLOSE
+	_IOERR_SEEK              _ErrorCode = util.IOERR_SEEK
+	_IOERR_DELETE_NOENT      _ErrorCode = util.IOERR_DELETE_NOENT
+	_CANTOPEN_FULLPATH       _ErrorCode = util.CANTOPEN_FULLPATH
+	_OK_SYMLINK              _ErrorCode = util.OK_SYMLINK
+)
+
+// OpenFlag is a flag for the [VFS] Open method.
+//
+// https://www.sqlite.org/c3ref/c_open_autoproxy.html
+type OpenFlag uint32
+
+const (
+	OPEN_READONLY      OpenFlag = 0x00000001 /* Ok for sqlite3_open_v2() */
+	OPEN_READWRITE     OpenFlag = 0x00000002 /* Ok for sqlite3_open_v2() */
+	OPEN_CREATE        OpenFlag = 0x00000004 /* Ok for sqlite3_open_v2() */
+	OPEN_DELETEONCLOSE OpenFlag = 0x00000008 /* VFS only */
+	OPEN_EXCLUSIVE     OpenFlag = 0x00000010 /* VFS only */
+	OPEN_AUTOPROXY     OpenFlag = 0x00000020 /* VFS only */
+	OPEN_URI           OpenFlag = 0x00000040 /* Ok for sqlite3_open_v2() */
+	OPEN_MEMORY        OpenFlag = 0x00000080 /* Ok for sqlite3_open_v2() */
+	OPEN_MAIN_DB       OpenFlag = 0x00000100 /* VFS only */
+	OPEN_TEMP_DB       OpenFlag = 0x00000200 /* VFS only */
+	OPEN_TRANSIENT_DB  OpenFlag = 0x00000400 /* VFS only */
+	OPEN_MAIN_JOURNAL  OpenFlag = 0x00000800 /* VFS only */
+	OPEN_TEMP_JOURNAL  OpenFlag = 0x00001000 /* VFS only */
+	OPEN_SUBJOURNAL    OpenFlag = 0x00002000 /* VFS only */
+	OPEN_SUPER_JOURNAL OpenFlag = 0x00004000 /* VFS only */
+	OPEN_NOMUTEX       OpenFlag = 0x00008000 /* Ok for sqlite3_open_v2() */
+	OPEN_FULLMUTEX     OpenFlag = 0x00010000 /* Ok for sqlite3_open_v2() */
+	OPEN_SHAREDCACHE   OpenFlag = 0x00020000 /* Ok for sqlite3_open_v2() */
+	OPEN_PRIVATECACHE  OpenFlag = 0x00040000 /* Ok for sqlite3_open_v2() */
+	OPEN_WAL           OpenFlag = 0x00080000 /* VFS only */
+	OPEN_NOFOLLOW      OpenFlag = 0x01000000 /* Ok for sqlite3_open_v2() */
+)
+
+// AccessFlag is a flag for the [VFS] Access method.
+//
+// https://www.sqlite.org/c3ref/c_access_exists.html
+type AccessFlag uint32
+
+const (
+	ACCESS_EXISTS    AccessFlag = 0
+	ACCESS_READWRITE AccessFlag = 1 /* Used by PRAGMA temp_store_directory */
+	ACCESS_READ      AccessFlag = 2 /* Unused */
+)
+
+// SyncFlag is a flag for the [File] Sync method.
+//
+// https://www.sqlite.org/c3ref/c_sync_dataonly.html
+type SyncFlag uint32
+
+const (
+	SYNC_NORMAL   SyncFlag = 0x00002
+	SYNC_FULL     SyncFlag = 0x00003
+	SYNC_DATAONLY SyncFlag = 0x00010
+)
+
+// LockLevel is a value used with [File] Lock and Unlock methods.
+//
+// https://www.sqlite.org/c3ref/c_lock_exclusive.html
+type LockLevel uint32
+
+const (
+	// No locks are held on the database.
+	// The database may be neither read nor written.
+	// Any internally cached data is considered suspect and subject to
+	// verification against the database file before being used.
+	// Other processes can read or write the database as their own locking
+	// states permit.
+	// This is the default state.
+	LOCK_NONE LockLevel = 0 /* xUnlock() only */
+
+	// The database may be read but not written.
+	// Any number of processes can hold SHARED locks at the same time,
+	// hence there can be many simultaneous readers.
+	// But no other thread or process is allowed to write to the database file
+	// while one or more SHARED locks are active.
+	LOCK_SHARED LockLevel = 1 /* xLock() or xUnlock() */
+
+	// A RESERVED lock means that the process is planning on writing to the
+	// database file at some point in the future but that it is currently just
+	// reading from the file.
+	// Only a single RESERVED lock may be active at one time,
+	// though multiple SHARED locks can coexist with a single RESERVED lock.
+	// RESERVED differs from PENDING in that new SHARED locks can be acquired
+	// while there is a RESERVED lock.
+	LOCK_RESERVED LockLevel = 2 /* xLock() only */
+
+	// A PENDING lock means that the process holding the lock wants to write to
+	// the database as soon as possible and is just waiting on all current
+	// SHARED locks to clear so that it can get an EXCLUSIVE lock.
+	// No new SHARED locks are permitted against the database if a PENDING lock
+	// is active, though existing SHARED locks are allowed to continue.
+	LOCK_PENDING LockLevel = 3 /* internal use only */
+
+	// An EXCLUSIVE lock is needed in order to write to the database file.
+	// Only one EXCLUSIVE lock is allowed on the file and no other locks of any
+	// kind are allowed to coexist with an EXCLUSIVE lock.
+	// In order to maximize concurrency, SQLite works to minimize the amount of
+	// time that EXCLUSIVE locks are held.
+	LOCK_EXCLUSIVE LockLevel = 4 /* xLock() only */
+)
+
+// DeviceCharacteristic is a flag retuned by the [File] DeviceCharacteristics method.
+//
+// https://www.sqlite.org/c3ref/c_iocap_atomic.html
+type DeviceCharacteristic uint32
+
+const (
+	IOCAP_ATOMIC                DeviceCharacteristic = 0x00000001
+	IOCAP_ATOMIC512             DeviceCharacteristic = 0x00000002
+	IOCAP_ATOMIC1K              DeviceCharacteristic = 0x00000004
+	IOCAP_ATOMIC2K              DeviceCharacteristic = 0x00000008
+	IOCAP_ATOMIC4K              DeviceCharacteristic = 0x00000010
+	IOCAP_ATOMIC8K              DeviceCharacteristic = 0x00000020
+	IOCAP_ATOMIC16K             DeviceCharacteristic = 0x00000040
+	IOCAP_ATOMIC32K             DeviceCharacteristic = 0x00000080
+	IOCAP_ATOMIC64K             DeviceCharacteristic = 0x00000100
+	IOCAP_SAFE_APPEND           DeviceCharacteristic = 0x00000200
+	IOCAP_SEQUENTIAL            DeviceCharacteristic = 0x00000400
+	IOCAP_UNDELETABLE_WHEN_OPEN DeviceCharacteristic = 0x00000800
+	IOCAP_POWERSAFE_OVERWRITE   DeviceCharacteristic = 0x00001000
+	IOCAP_IMMUTABLE             DeviceCharacteristic = 0x00002000
+	IOCAP_BATCH_ATOMIC          DeviceCharacteristic = 0x00004000
+)
+
+// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html
+type _FcntlOpcode uint32
+
+const (
+	_FCNTL_LOCKSTATE             _FcntlOpcode = 1
+	_FCNTL_GET_LOCKPROXYFILE     _FcntlOpcode = 2
+	_FCNTL_SET_LOCKPROXYFILE     _FcntlOpcode = 3
+	_FCNTL_LAST_ERRNO            _FcntlOpcode = 4
+	_FCNTL_SIZE_HINT             _FcntlOpcode = 5
+	_FCNTL_CHUNK_SIZE            _FcntlOpcode = 6
+	_FCNTL_FILE_POINTER          _FcntlOpcode = 7
+	_FCNTL_SYNC_OMITTED          _FcntlOpcode = 8
+	_FCNTL_WIN32_AV_RETRY        _FcntlOpcode = 9
+	_FCNTL_PERSIST_WAL           _FcntlOpcode = 10
+	_FCNTL_OVERWRITE             _FcntlOpcode = 11
+	_FCNTL_VFSNAME               _FcntlOpcode = 12
+	_FCNTL_POWERSAFE_OVERWRITE   _FcntlOpcode = 13
+	_FCNTL_PRAGMA                _FcntlOpcode = 14
+	_FCNTL_BUSYHANDLER           _FcntlOpcode = 15
+	_FCNTL_TEMPFILENAME          _FcntlOpcode = 16
+	_FCNTL_MMAP_SIZE             _FcntlOpcode = 18
+	_FCNTL_TRACE                 _FcntlOpcode = 19
+	_FCNTL_HAS_MOVED             _FcntlOpcode = 20
+	_FCNTL_SYNC                  _FcntlOpcode = 21
+	_FCNTL_COMMIT_PHASETWO       _FcntlOpcode = 22
+	_FCNTL_WIN32_SET_HANDLE      _FcntlOpcode = 23
+	_FCNTL_WAL_BLOCK             _FcntlOpcode = 24
+	_FCNTL_ZIPVFS                _FcntlOpcode = 25
+	_FCNTL_RBU                   _FcntlOpcode = 26
+	_FCNTL_VFS_POINTER           _FcntlOpcode = 27
+	_FCNTL_JOURNAL_POINTER       _FcntlOpcode = 28
+	_FCNTL_WIN32_GET_HANDLE      _FcntlOpcode = 29
+	_FCNTL_PDB                   _FcntlOpcode = 30
+	_FCNTL_BEGIN_ATOMIC_WRITE    _FcntlOpcode = 31
+	_FCNTL_COMMIT_ATOMIC_WRITE   _FcntlOpcode = 32
+	_FCNTL_ROLLBACK_ATOMIC_WRITE _FcntlOpcode = 33
+	_FCNTL_LOCK_TIMEOUT          _FcntlOpcode = 34
+	_FCNTL_DATA_VERSION          _FcntlOpcode = 35
+	_FCNTL_SIZE_LIMIT            _FcntlOpcode = 36
+	_FCNTL_CKPT_DONE             _FcntlOpcode = 37
+	_FCNTL_RESERVE_BYTES         _FcntlOpcode = 38
+	_FCNTL_CKPT_START            _FcntlOpcode = 39
+	_FCNTL_EXTERNAL_READER       _FcntlOpcode = 40
+	_FCNTL_CKSM_FILE             _FcntlOpcode = 41
+	_FCNTL_RESET_CACHE           _FcntlOpcode = 42
+)

sqlite3vfs/tests/mptest/mptest_test.go

@@ -0,0 +1,179 @@
+package mptest
+
+import (
+	"bytes"
+	"context"
+	"crypto/rand"
+	"embed"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3/sqlite3vfs"
+	"github.com/tetratelabs/wazero"
+	"github.com/tetratelabs/wazero/api"
+	"github.com/tetratelabs/wazero/imports/wasi_snapshot_preview1"
+)
+
+//go:embed testdata/mptest.wasm
+var binary []byte
+
+//go:embed testdata/*.*test
+var scripts embed.FS
+
+var (
+	rt        wazero.Runtime
+	module    wazero.CompiledModule
+	instances atomic.Uint64
+)
+
+func init() {
+	ctx := context.TODO()
+
+	rt = wazero.NewRuntime(ctx)
+	wasi_snapshot_preview1.MustInstantiate(ctx, rt)
+
+	env := sqlite3vfs.ExportHostFunctions(rt.NewHostModuleBuilder("env"))
+	env.NewFunctionBuilder().WithFunc(system).Export("system")
+	_, err := env.Instantiate(ctx)
+	if err != nil {
+		panic(err)
+	}
+
+	module, err = rt.CompileModule(ctx, binary)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func config(ctx context.Context) wazero.ModuleConfig {
+	name := strconv.FormatUint(instances.Add(1), 10)
+	log := ctx.Value(logger{}).(io.Writer)
+	fs, err := fs.Sub(scripts, "testdata")
+	if err != nil {
+		panic(err)
+	}
+
+	return wazero.NewModuleConfig().
+		WithName(name).WithStdout(log).WithStderr(log).WithFS(fs).
+		WithSysWalltime().WithSysNanotime().WithSysNanosleep().
+		WithOsyield(runtime.Gosched).
+		WithRandSource(rand.Reader)
+}
+
+func system(ctx context.Context, mod api.Module, ptr uint32) uint32 {
+	buf, _ := mod.Memory().Read(ptr, mod.Memory().Size()-ptr)
+	buf = buf[:bytes.IndexByte(buf, 0)]
+
+	args := strings.Split(string(buf), " ")
+	for i := range args {
+		args[i] = strings.Trim(args[i], `"`)
+	}
+	args = args[:len(args)-1]
+
+	cfg := config(ctx).WithArgs(args...)
+	go func() {
+		ctx, vfs := sqlite3vfs.NewContext(ctx)
+		mod, _ := rt.InstantiateModule(ctx, module, cfg)
+		mod.Close(ctx)
+		vfs.Close()
+	}()
+	return 0
+}
+
+func Test_config01(t *testing.T) {
+	ctx, vfs := sqlite3vfs.NewContext(newContext(t))
+	name := filepath.Join(t.TempDir(), "test.db")
+	cfg := config(ctx).WithArgs("mptest", name, "config01.test")
+	mod, err := rt.InstantiateModule(ctx, module, cfg)
+	if err != nil {
+		t.Error(err)
+	}
+	mod.Close(ctx)
+	vfs.Close()
+}
+
+func Test_config02(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping in short mode")
+	}
+	if os.Getenv("CI") != "" {
+		t.Skip("skipping in CI")
+	}
+
+	ctx, vfs := sqlite3vfs.NewContext(newContext(t))
+	name := filepath.Join(t.TempDir(), "test.db")
+	cfg := config(ctx).WithArgs("mptest", name, "config02.test")
+	mod, err := rt.InstantiateModule(ctx, module, cfg)
+	if err != nil {
+		t.Error(err)
+	}
+	mod.Close(ctx)
+	vfs.Close()
+}
+
+func Test_crash01(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping in short mode")
+	}
+
+	ctx, vfs := sqlite3vfs.NewContext(newContext(t))
+	name := filepath.Join(t.TempDir(), "test.db")
+	cfg := config(ctx).WithArgs("mptest", name, "crash01.test")
+	mod, err := rt.InstantiateModule(ctx, module, cfg)
+	if err != nil {
+		t.Error(err)
+	}
+	mod.Close(ctx)
+	vfs.Close()
+}
+
+func Test_multiwrite01(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping in short mode")
+	}
+
+	ctx, vfs := sqlite3vfs.NewContext(newContext(t))
+	name := filepath.Join(t.TempDir(), "test.db")
+	cfg := config(ctx).WithArgs("mptest", name, "multiwrite01.test")
+	mod, err := rt.InstantiateModule(ctx, module, cfg)
+	if err != nil {
+		t.Error(err)
+	}
+	mod.Close(ctx)
+	vfs.Close()
+}
+
+func newContext(t *testing.T) context.Context {
+	return context.WithValue(context.Background(), logger{}, &testWriter{T: t})
+}
+
+type logger struct{}
+
+type testWriter struct {
+	*testing.T
+	buf []byte
+	mtx sync.Mutex
+}
+
+func (l *testWriter) Write(p []byte) (n int, err error) {
+	l.mtx.Lock()
+	defer l.mtx.Unlock()
+
+	l.buf = append(l.buf, p...)
+	for {
+		before, after, found := bytes.Cut(l.buf, []byte("\n"))
+		if !found {
+			return len(p), nil
+		}
+		l.Logf("%s", before)
+		l.buf = after
+	}
+}

sqlite3vfs/tests/mptest/testdata/.gitattributes

@@ -0,0 +1,2 @@
+mptest.wasm filter=lfs diff=lfs merge=lfs -text
+*.*test -crlf

sqlite3vfs/tests/mptest/testdata/.gitignore

@@ -0,0 +1 @@
+mptest.c

sqlite3vfs/tests/mptest/testdata/build.sh

@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+cd -P -- "$(dirname -- "$0")"
+
+ROOT=../../../../
+BINARYEN="$ROOT/tools/binaryen-version_112/bin"
+WASI_SDK="$ROOT/tools/wasi-sdk-20.0/bin"
+
+"$WASI_SDK/clang" --target=wasm32-wasi -flto -g0 -O2 \
+  -o mptest.wasm main.c \
+	-I"$ROOT/sqlite3" \
+	-mmutable-globals \
+	-mbulk-memory -mreference-types \
+	-mnontrapping-fptoint -msign-ext \
+	-Wl,--stack-first \
+	-Wl,--import-undefined \
+	-DSQLITE_DEFAULT_SYNCHRONOUS=0 \
+	-DSQLITE_DEFAULT_LOCKING_MODE=0 \
+	-DHAVE_USLEEP -DSQLITE_NO_SYNC \
+	-DSQLITE_THREADSAFE=0 -DSQLITE_OMIT_LOAD_EXTENSION \
+	-D_WASI_EMULATED_GETPID -lwasi-emulated-getpid
+
+"$BINARYEN/wasm-opt" -g -O2 mptest.wasm -o mptest.tmp \
+	--enable-multivalue --enable-mutable-globals \
+	--enable-bulk-memory --enable-reference-types \
+	--enable-nontrapping-float-to-int --enable-sign-ext
+mv mptest.tmp mptest.wasm

sqlite3vfs/tests/mptest/testdata/config01.test

@@ -0,0 +1,46 @@
+/*
+** Configure five tasks in different ways, then run tests.
+*/
+--if vfsname() GLOB 'unix'
+PRAGMA page_size=8192;
+--task 1
+  PRAGMA journal_mode=PERSIST;
+  PRAGMA mmap_size=0;
+--end
+--task 2
+  PRAGMA journal_mode=TRUNCATE;
+  PRAGMA mmap_size=28672;
+--end
+--task 3
+  PRAGMA journal_mode=MEMORY;
+--end
+--task 4
+  PRAGMA journal_mode=OFF;
+--end
+--task 4
+  PRAGMA mmap_size(268435456);
+--end
+--source multiwrite01.test
+--wait all
+PRAGMA page_size=16384;
+VACUUM;
+CREATE TABLE pgsz(taskid, sz INTEGER);
+--task 1
+  INSERT INTO pgsz VALUES(1, eval('PRAGMA page_size'));
+--end
+--task 2
+  INSERT INTO pgsz VALUES(2, eval('PRAGMA page_size'));
+--end
+--task 3
+  INSERT INTO pgsz VALUES(3, eval('PRAGMA page_size'));
+--end
+--task 4
+  INSERT INTO pgsz VALUES(4, eval('PRAGMA page_size'));
+--end
+--task 5
+  INSERT INTO pgsz VALUES(5, eval('PRAGMA page_size'));
+--end
+--source multiwrite01.test
+--wait all
+SELECT sz FROM pgsz;
+--match 16384 16384 16384 16384 16384

sqlite3vfs/tests/mptest/testdata/config02.test

@@ -0,0 +1,123 @@
+/*
+** Configure five tasks in different ways, then run tests.
+*/
+PRAGMA page_size=512;
+--task 1
+  PRAGMA mmap_size=0;
+--end
+--task 2
+  PRAGMA mmap_size=28672;
+--end
+--task 3
+  PRAGMA mmap_size=8192;
+--end
+--task 4
+  PRAGMA mmap_size=65536;
+--end
+--task 5
+  PRAGMA mmap_size=268435456;
+--end
+--source multiwrite01.test
+--source crash02.subtest
+PRAGMA page_size=1024;
+VACUUM;
+CREATE TABLE pgsz(taskid, sz INTEGER);
+--task 1
+  INSERT INTO pgsz VALUES(1, eval('PRAGMA page_size'));
+--end
+--task 2
+  INSERT INTO pgsz VALUES(2, eval('PRAGMA page_size'));
+--end
+--task 3
+  INSERT INTO pgsz VALUES(3, eval('PRAGMA page_size'));
+--end
+--task 4
+  INSERT INTO pgsz VALUES(4, eval('PRAGMA page_size'));
+--end
+--task 5
+  INSERT INTO pgsz VALUES(5, eval('PRAGMA page_size'));
+--end
+--source multiwrite01.test
+--source crash02.subtest
+--wait all
+SELECT sz FROM pgsz;
+--match 1024 1024 1024 1024 1024
+PRAGMA page_size=2048;
+VACUUM;
+DELETE FROM pgsz;
+--task 1
+  INSERT INTO pgsz VALUES(1, eval('PRAGMA page_size'));
+--end
+--task 2
+  INSERT INTO pgsz VALUES(2, eval('PRAGMA page_size'));
+--end
+--task 3
+  INSERT INTO pgsz VALUES(3, eval('PRAGMA page_size'));
+--end
+--task 4
+  INSERT INTO pgsz VALUES(4, eval('PRAGMA page_size'));
+--end
+--task 5
+  INSERT INTO pgsz VALUES(5, eval('PRAGMA page_size'));
+--end
+--source multiwrite01.test
+--source crash02.subtest
+--wait all
+SELECT sz FROM pgsz;
+--match 2048 2048 2048 2048 2048
+PRAGMA page_size=8192;
+VACUUM;
+DELETE FROM pgsz;
+--task 1
+  INSERT INTO pgsz VALUES(1, eval('PRAGMA page_size'));
+--end
+--task 2
+  INSERT INTO pgsz VALUES(2, eval('PRAGMA page_size'));
+--end
+--task 3
+  INSERT INTO pgsz VALUES(3, eval('PRAGMA page_size'));
+--end
+--task 4
+  INSERT INTO pgsz VALUES(4, eval('PRAGMA page_size'));
+--end
+--task 5
+  INSERT INTO pgsz VALUES(5, eval('PRAGMA page_size'));
+--end
+--source multiwrite01.test
+--source crash02.subtest
+--wait all
+SELECT sz FROM pgsz;
+--match 8192 8192 8192 8192 8192
+PRAGMA page_size=16384;
+VACUUM;
+DELETE FROM pgsz;
+--task 1
+  INSERT INTO pgsz VALUES(1, eval('PRAGMA page_size'));
+--end
+--task 2
+  INSERT INTO pgsz VALUES(2, eval('PRAGMA page_size'));
+--end
+--task 3
+  INSERT INTO pgsz VALUES(3, eval('PRAGMA page_size'));
+--end
+--task 4
+  INSERT INTO pgsz VALUES(4, eval('PRAGMA page_size'));
+--end
+--task 5
+  INSERT INTO pgsz VALUES(5, eval('PRAGMA page_size'));
+--end
+--source multiwrite01.test
+--source crash02.subtest
+--wait all
+SELECT sz FROM pgsz;
+--match 16384 16384 16384 16384 16384
+PRAGMA auto_vacuum=FULL;
+VACUUM;
+--source multiwrite01.test
+--source crash02.subtest
+--wait all
+PRAGMA auto_vacuum=FULL;
+PRAGMA page_size=512;
+VACUUM;
+--source multiwrite01.test
+--source crash02.subtest

sqlite3vfs/tests/mptest/testdata/crash01.test

@@ -0,0 +1,106 @@
+/* Test cases involving incomplete transactions that must be rolled back.
+*/
+--task 1
+  DROP TABLE IF EXISTS t1;
+  CREATE TABLE t1(a INTEGER PRIMARY KEY, b);
+  --sleep 1
+  INSERT INTO t1 VALUES(1, randomblob(2000));
+  INSERT INTO t1 VALUES(2, randomblob(1000));
+  --sleep 1
+  INSERT INTO t1 SELECT a+2, randomblob(1500) FROM t1;
+  INSERT INTO t1 SELECT a+4, randomblob(1500) FROM t1;
+  INSERT INTO t1 SELECT a+8, randomblob(1500) FROM t1;
+  --sleep 1
+  INSERT INTO t1 SELECT a+16, randomblob(1500) FROM t1;
+  --sleep 1
+  INSERT INTO t1 SELECT a+32, randomblob(1500) FROM t1;
+  SELECT count(*) FROM t1;
+  --match 64
+  SELECT avg(length(b)) FROM t1;
+  --match 1500.0
+  --sleep 2
+  UPDATE t1 SET b='x'||a||'y';
+  SELECT sum(length(b)) FROM t1;
+  --match 247
+  SELECT a FROM t1 WHERE b='x17y';
+  --match 17
+  CREATE INDEX t1b ON t1(b);
+  SELECT a FROM t1 WHERE b='x17y';
+  --match 17
+  SELECT a FROM t1 WHERE b GLOB 'x2?y' ORDER BY b DESC LIMIT 5;
+  --match 29 28 27 26 25
+--end
+--wait 1
+--task 2
+  DROP TABLE IF EXISTS t2;
+  CREATE TABLE t2(a INTEGER PRIMARY KEY, b);
+  INSERT INTO t2 SELECT a, b FROM t1;
+  UPDATE t1 SET b='x'||a||'y';
+  SELECT sum(length(b)) FROM t2;
+  --match 247
+  SELECT a FROM t2 WHERE b='x17y';
+  --match 17
+  CREATE INDEX t2b ON t2(b);
+  SELECT a FROM t2 WHERE b='x17y';
+  --match 17
+  SELECT a FROM t2 WHERE b GLOB 'x2?y' ORDER BY b DESC LIMIT 5;
+  --match 29 28 27 26 25
+--end
+--task 3
+  DROP TABLE IF EXISTS t3;
+  CREATE TABLE t3(a INTEGER PRIMARY KEY, b);
+  INSERT INTO t3 SELECT a, b FROM t1;
+  UPDATE t1 SET b='x'||a||'y';
+  SELECT sum(length(b)) FROM t3;
+  --match 247
+  SELECT a FROM t3 WHERE b='x17y';
+  --match 17
+  CREATE INDEX t3b ON t3(b);
+  SELECT a FROM t3 WHERE b='x17y';
+  --match 17
+  SELECT a FROM t3 WHERE b GLOB 'x2?y' ORDER BY b DESC LIMIT 5;
+  --match 29 28 27 26 25
+--end
+--task 4
+  DROP TABLE IF EXISTS t4;
+  CREATE TABLE t4(a INTEGER PRIMARY KEY, b);
+  INSERT INTO t4 SELECT a, b FROM t1;
+  UPDATE t1 SET b='x'||a||'y';
+  SELECT sum(length(b)) FROM t4;
+  --match 247
+  SELECT a FROM t4 WHERE b='x17y';
+  --match 17
+  CREATE INDEX t4b ON t4(b);
+  SELECT a FROM t4 WHERE b='x17y';
+  --match 17
+  SELECT a FROM t4 WHERE b GLOB 'x2?y' ORDER BY b DESC LIMIT 5;
+  --match 29 28 27 26 25
+--end
+--task 5
+  DROP TABLE IF EXISTS t5;
+  CREATE TABLE t5(a INTEGER PRIMARY KEY, b);
+  INSERT INTO t5 SELECT a, b FROM t1;
+  UPDATE t1 SET b='x'||a||'y';
+  SELECT sum(length(b)) FROM t5;
+  --match 247
+  SELECT a FROM t5 WHERE b='x17y';
+  --match 17
+  CREATE INDEX t5b ON t5(b);
+  SELECT a FROM t5 WHERE b='x17y';
+  --match 17
+  SELECT a FROM t5 WHERE b GLOB 'x2?y' ORDER BY b DESC LIMIT 5;
+  --match 29 28 27 26 25
+--end
+
+--wait all
+/* After the database file has been set up, run the crash2 subscript
+** multiple times. */
+--source crash02.subtest
+--source crash02.subtest
+--source crash02.subtest
+--source crash02.subtest
+--source crash02.subtest
+--source crash02.subtest
+--source crash02.subtest
+--source crash02.subtest
+--source crash02.subtest

sqlite3vfs/tests/mptest/testdata/crash02.subtest

@@ -0,0 +1,53 @@
+/*
+** This script is called from crash01.test and config02.test and perhaps other
+** script.  After the database file has been set up, make a big rollback 
+** journal in client 1, then crash client 1.
+** Then in the other clients, do an integrity check.
+*/
+--task 1 leave-hot-journal
+  --sleep 5
+  --finish
+  PRAGMA cache_size=10;
+  BEGIN;
+  UPDATE t1 SET b=randomblob(20000);
+  UPDATE t2 SET b=randomblob(20000);
+  UPDATE t3 SET b=randomblob(20000);
+  UPDATE t4 SET b=randomblob(20000);
+  UPDATE t5 SET b=randomblob(20000);
+  UPDATE t1 SET b=NULL;
+  UPDATE t2 SET b=NULL;
+  UPDATE t3 SET b=NULL;
+  UPDATE t4 SET b=NULL;
+  UPDATE t5 SET b=NULL;
+  --print Task one crashing an incomplete transaction
+  --exit 1
+--end
+--task 2 integrity_check-2
+  SELECT count(*) FROM t1;
+  --match 64
+  --sleep 100
+  PRAGMA integrity_check(10);
+  --match ok
+--end
+--task 3 integrity_check-3
+  SELECT count(*) FROM t1;
+  --match 64
+  --sleep 100
+  PRAGMA integrity_check(10);
+  --match ok
+--end
+--task 4 integrity_check-4
+  SELECT count(*) FROM t1;
+  --match 64
+  --sleep 100
+  PRAGMA integrity_check(10);
+  --match ok
+--end
+--task 5 integrity_check-5
+  SELECT count(*) FROM t1;
+  --match 64
+  --sleep 100
+  PRAGMA integrity_check(10);
+  --match ok
+--end
+--wait all

sqlite3vfs/tests/mptest/testdata/main.c

@@ -0,0 +1,18 @@
+#include <stdbool.h>
+#include <stddef.h>
+
+// Configuration
+#include "sqlite_cfg.h"
+// Amalgamation
+#include "sqlite3.c"
+// VFS
+#include "vfs.c"
+
+__attribute__((constructor)) void init() { sqlite3_initialize(); }
+
+static int dont_unlink(const char *pathname) { return 0; }
+#define sqlite3_enable_load_extension(...)
+#define sqlite3_trace(...)
+#define unlink dont_unlink
+#undef UNUSED_PARAMETER
+#include "mptest.c"

sqlite3vfs/tests/mptest/testdata/mptest.wasm

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:aafb873c26d32dbf7498e4c4dd243eb6411c056432818121463d8cb49bc15f70
+size 1479293

sqlite3vfs/tests/mptest/testdata/multiwrite01.test

@@ -0,0 +1,415 @@
+/*
+** This script sets up five different tasks all writing and updating
+** the database at the same time, but each in its own table.
+*/
+--task 1 build-t1
+  DROP TABLE IF EXISTS t1;
+  CREATE TABLE t1(a INTEGER PRIMARY KEY, b);
+  --sleep 1
+  INSERT INTO t1 VALUES(1, randomblob(2000));
+  INSERT INTO t1 VALUES(2, randomblob(1000));
+  --sleep 1
+  INSERT INTO t1 SELECT a+2, randomblob(1500) FROM t1;
+  INSERT INTO t1 SELECT a+4, randomblob(1500) FROM t1;
+  INSERT INTO t1 SELECT a+8, randomblob(1500) FROM t1;
+  --sleep 1
+  INSERT INTO t1 SELECT a+16, randomblob(1500) FROM t1;
+  --sleep 1
+  INSERT INTO t1 SELECT a+32, randomblob(1500) FROM t1;
+  SELECT count(*) FROM t1;
+  --match 64
+  SELECT avg(length(b)) FROM t1;
+  --match 1500.0
+  --sleep 2
+  UPDATE t1 SET b='x'||a||'y';
+  SELECT sum(length(b)) FROM t1;
+  --match 247
+  SELECT a FROM t1 WHERE b='x17y';
+  --match 17
+  CREATE INDEX t1b ON t1(b);
+  SELECT a FROM t1 WHERE b='x17y';
+  --match 17
+  SELECT a FROM t1 WHERE b GLOB 'x2?y' ORDER BY b DESC LIMIT 5;
+  --match 29 28 27 26 25
+--end
+
+
+--task 2 build-t2
+  DROP TABLE IF EXISTS t2;
+  CREATE TABLE t2(a INTEGER PRIMARY KEY, b);
+  --sleep 1
+  INSERT INTO t2 VALUES(1, randomblob(2000));
+  INSERT INTO t2 VALUES(2, randomblob(1000));
+  --sleep 1
+  INSERT INTO t2 SELECT a+2, randomblob(1500) FROM t2;
+  INSERT INTO t2 SELECT a+4, randomblob(1500) FROM t2;
+  INSERT INTO t2 SELECT a+8, randomblob(1500) FROM t2;
+  --sleep 1
+  INSERT INTO t2 SELECT a+16, randomblob(1500) FROM t2;
+  --sleep 1
+  INSERT INTO t2 SELECT a+32, randomblob(1500) FROM t2;
+  SELECT count(*) FROM t2;
+  --match 64
+  SELECT avg(length(b)) FROM t2;
+  --match 1500.0
+  --sleep 2
+  UPDATE t2 SET b='x'||a||'y';
+  SELECT sum(length(b)) FROM t2;
+  --match 247
+  SELECT a FROM t2 WHERE b='x17y';
+  --match 17
+  CREATE INDEX t2b ON t2(b);
+  SELECT a FROM t2 WHERE b='x17y';
+  --match 17
+  SELECT a FROM t2 WHERE b GLOB 'x2?y' ORDER BY b DESC LIMIT 5;
+  --match 29 28 27 26 25
+--end
+
+--task 3 build-t3
+  DROP TABLE IF EXISTS t3;
+  CREATE TABLE t3(a INTEGER PRIMARY KEY, b);
+  --sleep 1
+  INSERT INTO t3 VALUES(1, randomblob(2000));
+  INSERT INTO t3 VALUES(2, randomblob(1000));
+  --sleep 1
+  INSERT INTO t3 SELECT a+2, randomblob(1500) FROM t3;
+  INSERT INTO t3 SELECT a+4, randomblob(1500) FROM t3;
+  INSERT INTO t3 SELECT a+8, randomblob(1500) FROM t3;
+  --sleep 1
+  INSERT INTO t3 SELECT a+16, randomblob(1500) FROM t3;
+  --sleep 1
+  INSERT INTO t3 SELECT a+32, randomblob(1500) FROM t3;
+  SELECT count(*) FROM t3;
+  --match 64
+  SELECT avg(length(b)) FROM t3;
+  --match 1500.0
+  --sleep 2
+  UPDATE t3 SET b='x'||a||'y';
+  SELECT sum(length(b)) FROM t3;
+  --match 247
+  SELECT a FROM t3 WHERE b='x17y';
+  --match 17
+  CREATE INDEX t3b ON t3(b);
+  SELECT a FROM t3 WHERE b='x17y';
+  --match 17
+  SELECT a FROM t3 WHERE b GLOB 'x2?y' ORDER BY b DESC LIMIT 5;
+  --match 29 28 27 26 25
+--end
+
+--task 4 build-t4
+  DROP TABLE IF EXISTS t4;
+  CREATE TABLE t4(a INTEGER PRIMARY KEY, b);
+  --sleep 1
+  INSERT INTO t4 VALUES(1, randomblob(2000));
+  INSERT INTO t4 VALUES(2, randomblob(1000));
+  --sleep 1
+  INSERT INTO t4 SELECT a+2, randomblob(1500) FROM t4;
+  INSERT INTO t4 SELECT a+4, randomblob(1500) FROM t4;
+  INSERT INTO t4 SELECT a+8, randomblob(1500) FROM t4;
+  --sleep 1
+  INSERT INTO t4 SELECT a+16, randomblob(1500) FROM t4;
+  --sleep 1
+  INSERT INTO t4 SELECT a+32, randomblob(1500) FROM t4;
+  SELECT count(*) FROM t4;
+  --match 64
+  SELECT avg(length(b)) FROM t4;
+  --match 1500.0
+  --sleep 2
+  UPDATE t4 SET b='x'||a||'y';
+  SELECT sum(length(b)) FROM t4;
+  --match 247
+  SELECT a FROM t4 WHERE b='x17y';
+  --match 17
+  CREATE INDEX t4b ON t4(b);
+  SELECT a FROM t4 WHERE b='x17y';
+  --match 17
+  SELECT a FROM t4 WHERE b GLOB 'x2?y' ORDER BY b DESC LIMIT 5;
+  --match 29 28 27 26 25
+--end
+
+--task 5 build-t5
+  DROP TABLE IF EXISTS t5;
+  CREATE TABLE t5(a INTEGER PRIMARY KEY, b);
+  --sleep 1
+  INSERT INTO t5 VALUES(1, randomblob(2000));
+  INSERT INTO t5 VALUES(2, randomblob(1000));
+  --sleep 1
+  INSERT INTO t5 SELECT a+2, randomblob(1500) FROM t5;
+  INSERT INTO t5 SELECT a+4, randomblob(1500) FROM t5;
+  INSERT INTO t5 SELECT a+8, randomblob(1500) FROM t5;
+  --sleep 1
+  INSERT INTO t5 SELECT a+16, randomblob(1500) FROM t5;
+  --sleep 1
+  INSERT INTO t5 SELECT a+32, randomblob(1500) FROM t5;
+  SELECT count(*) FROM t5;
+  --match 64
+  SELECT avg(length(b)) FROM t5;
+  --match 1500.0
+  --sleep 2
+  UPDATE t5 SET b='x'||a||'y';
+  SELECT sum(length(b)) FROM t5;
+  --match 247
+  SELECT a FROM t5 WHERE b='x17y';
+  --match 17
+  CREATE INDEX t5b ON t5(b);
+  SELECT a FROM t5 WHERE b='x17y';
+  --match 17
+  SELECT a FROM t5 WHERE b GLOB 'x2?y' ORDER BY b DESC LIMIT 5;
+  --match 29 28 27 26 25
+--end
+
+--wait all
+SELECT count(*), sum(length(b)) FROM t1;
+--match 64 247
+SELECT count(*), sum(length(b)) FROM t2;
+--match 64 247
+SELECT count(*), sum(length(b)) FROM t3;
+--match 64 247
+SELECT count(*), sum(length(b)) FROM t4;
+--match 64 247
+SELECT count(*), sum(length(b)) FROM t5;
+--match 64 247
+
+--task 1
+  SELECT t1.a FROM t1, t2
+   WHERE t2.b GLOB 'x3?y' AND t1.b=('x'||(t2.a+3)||'y')
+   ORDER BY t1.a LIMIT 4
+  --match 33 34 35 36
+  SELECT t3.a FROM t3, t4
+   WHERE t4.b GLOB 'x4?y' AND t3.b=('x'||(t4.a+5)||'y')
+   ORDER BY t3.a LIMIT 7
+  --match 45 46 47 48 49 50 51
+--end
+--task 5
+  SELECT t1.a FROM t1, t2
+   WHERE t2.b GLOB 'x3?y' AND t1.b=('x'||(t2.a+3)||'y')
+   ORDER BY t1.a LIMIT 4
+  --match 33 34 35 36
+  SELECT t3.a FROM t3, t4
+   WHERE t4.b GLOB 'x4?y' AND t3.b=('x'||(t4.a+5)||'y')
+   ORDER BY t3.a LIMIT 7
+  --match 45 46 47 48 49 50 51
+--end
+--task 3
+  SELECT t1.a FROM t1, t2
+   WHERE t2.b GLOB 'x3?y' AND t1.b=('x'||(t2.a+3)||'y')
+   ORDER BY t1.a LIMIT 4
+  --match 33 34 35 36
+  SELECT t3.a FROM t3, t4
+   WHERE t4.b GLOB 'x4?y' AND t3.b=('x'||(t4.a+5)||'y')
+   ORDER BY t3.a LIMIT 7
+  --match 45 46 47 48 49 50 51
+--end
+--task 2
+  SELECT t1.a FROM t1, t2
+   WHERE t2.b GLOB 'x3?y' AND t1.b=('x'||(t2.a+3)||'y')
+   ORDER BY t1.a LIMIT 4
+  --match 33 34 35 36
+  SELECT t3.a FROM t3, t4
+   WHERE t4.b GLOB 'x4?y' AND t3.b=('x'||(t4.a+5)||'y')
+   ORDER BY t3.a LIMIT 7
+  --match 45 46 47 48 49 50 51
+--end
+--task 4
+  SELECT t1.a FROM t1, t2
+   WHERE t2.b GLOB 'x3?y' AND t1.b=('x'||(t2.a+3)||'y')
+   ORDER BY t1.a LIMIT 4
+  --match 33 34 35 36
+  SELECT t3.a FROM t3, t4
+   WHERE t4.b GLOB 'x4?y' AND t3.b=('x'||(t4.a+5)||'y')
+   ORDER BY t3.a LIMIT 7
+  --match 45 46 47 48 49 50 51
+--end
+--wait all
+
+--task 5
+  DROP INDEX t5b;
+  --sleep 5
+  PRAGMA integrity_check(10);
+  --match ok
+  CREATE INDEX t5b ON t5(b DESC);
+--end
+--task 3
+  DROP INDEX t3b;
+  --sleep 5
+  PRAGMA integrity_check(10);
+  --match ok
+  CREATE INDEX t3b ON t3(b DESC);
+--end
+--task 1
+  DROP INDEX t1b;
+  --sleep 5
+  PRAGMA integrity_check(10);
+  --match ok
+  CREATE INDEX t1b ON t1(b DESC);
+--end
+--task 2
+  DROP INDEX t2b;
+  --sleep 5
+  PRAGMA integrity_check(10);
+  --match ok
+  CREATE INDEX t2b ON t2(b DESC);
+--end
+--task 4
+  DROP INDEX t4b;
+  --sleep 5
+  PRAGMA integrity_check(10);
+  --match ok
+  CREATE INDEX t4b ON t4(b DESC);
+--end
+--wait all
+
+--task 1
+  SELECT t1.a FROM t1, t2
+   WHERE t2.b GLOB 'x3?y' AND t1.b=('x'||(t2.a+3)||'y')
+   ORDER BY t1.a LIMIT 4
+  --match 33 34 35 36
+  SELECT t3.a FROM t3, t4
+   WHERE t4.b GLOB 'x4?y' AND t3.b=('x'||(t4.a+5)||'y')
+   ORDER BY t3.a LIMIT 7
+  --match 45 46 47 48 49 50 51
+--end
+--task 5
+  SELECT t1.a FROM t1, t2
+   WHERE t2.b GLOB 'x3?y' AND t1.b=('x'||(t2.a+3)||'y')
+   ORDER BY t1.a LIMIT 4
+  --match 33 34 35 36
+  SELECT t3.a FROM t3, t4
+   WHERE t4.b GLOB 'x4?y' AND t3.b=('x'||(t4.a+5)||'y')
+   ORDER BY t3.a LIMIT 7
+  --match 45 46 47 48 49 50 51
+--end
+--task 3
+  SELECT t1.a FROM t1, t2
+   WHERE t2.b GLOB 'x3?y' AND t1.b=('x'||(t2.a+3)||'y')
+   ORDER BY t1.a LIMIT 4
+  --match 33 34 35 36
+  SELECT t3.a FROM t3, t4
+   WHERE t4.b GLOB 'x4?y' AND t3.b=('x'||(t4.a+5)||'y')
+   ORDER BY t3.a LIMIT 7
+  --match 45 46 47 48 49 50 51
+--end
+--task 2
+  SELECT t1.a FROM t1, t2
+   WHERE t2.b GLOB 'x3?y' AND t1.b=('x'||(t2.a+3)||'y')
+   ORDER BY t1.a LIMIT 4
+  --match 33 34 35 36
+  SELECT t3.a FROM t3, t4
+   WHERE t4.b GLOB 'x4?y' AND t3.b=('x'||(t4.a+5)||'y')
+   ORDER BY t3.a LIMIT 7
+  --match 45 46 47 48 49 50 51
+--end
+--task 4
+  SELECT t1.a FROM t1, t2
+   WHERE t2.b GLOB 'x3?y' AND t1.b=('x'||(t2.a+3)||'y')
+   ORDER BY t1.a LIMIT 4
+  --match 33 34 35 36
+  SELECT t3.a FROM t3, t4
+   WHERE t4.b GLOB 'x4?y' AND t3.b=('x'||(t4.a+5)||'y')
+   ORDER BY t3.a LIMIT 7
+  --match 45 46 47 48 49 50 51
+--end
+--wait all
+
+VACUUM;
+PRAGMA integrity_check(10);
+--match ok
+
+--task 1
+  UPDATE t1 SET b=randomblob(20000);
+  --sleep 5
+  UPDATE t1 SET b='x'||a||'y';
+  SELECT a FROM t1 WHERE b='x63y';
+  --match 63
+--end
+--task 2
+  UPDATE t2 SET b=randomblob(20000);
+  --sleep 5
+  UPDATE t2 SET b='x'||a||'y';
+  SELECT a FROM t2 WHERE b='x63y';
+  --match 63
+--end
+--task 3
+  UPDATE t3 SET b=randomblob(20000);
+  --sleep 5
+  UPDATE t3 SET b='x'||a||'y';
+  SELECT a FROM t3 WHERE b='x63y';
+  --match 63
+--end
+--task 4
+  UPDATE t4 SET b=randomblob(20000);
+  --sleep 5
+  UPDATE t4 SET b='x'||a||'y';
+  SELECT a FROM t4 WHERE b='x63y';
+  --match 63
+--end
+--task 5
+  UPDATE t5 SET b=randomblob(20000);
+  --sleep 5
+  UPDATE t5 SET b='x'||a||'y';
+  SELECT a FROM t5 WHERE b='x63y';
+  --match 63
+--end
+--wait all
+
+--task 1
+  SELECT t1.a FROM t1, t2
+   WHERE t2.b GLOB 'x3?y' AND t1.b=('x'||(t2.a+3)||'y')
+   ORDER BY t1.a LIMIT 4
+  --match 33 34 35 36
+  SELECT t3.a FROM t3, t4
+   WHERE t4.b GLOB 'x4?y' AND t3.b=('x'||(t4.a+5)||'y')
+   ORDER BY t3.a LIMIT 7
+  --match 45 46 47 48 49 50 51
+  PRAGMA integrity_check;
+  --match ok
+--end
+--task 5
+  SELECT t1.a FROM t1, t2
+   WHERE t2.b GLOB 'x3?y' AND t1.b=('x'||(t2.a+3)||'y')
+   ORDER BY t1.a LIMIT 4
+  --match 33 34 35 36
+  SELECT t3.a FROM t3, t4
+   WHERE t4.b GLOB 'x4?y' AND t3.b=('x'||(t4.a+5)||'y')
+   ORDER BY t3.a LIMIT 7
+  --match 45 46 47 48 49 50 51
+  PRAGMA integrity_check;
+  --match ok
+--end
+--task 3
+  SELECT t1.a FROM t1, t2
+   WHERE t2.b GLOB 'x3?y' AND t1.b=('x'||(t2.a+3)||'y')
+   ORDER BY t1.a LIMIT 4
+  --match 33 34 35 36
+  SELECT t3.a FROM t3, t4
+   WHERE t4.b GLOB 'x4?y' AND t3.b=('x'||(t4.a+5)||'y')
+   ORDER BY t3.a LIMIT 7
+  --match 45 46 47 48 49 50 51
+  PRAGMA integrity_check;
+  --match ok
+--end
+--task 2
+  SELECT t1.a FROM t1, t2
+   WHERE t2.b GLOB 'x3?y' AND t1.b=('x'||(t2.a+3)||'y')
+   ORDER BY t1.a LIMIT 4
+  --match 33 34 35 36
+  SELECT t3.a FROM t3, t4
+   WHERE t4.b GLOB 'x4?y' AND t3.b=('x'||(t4.a+5)||'y')
+   ORDER BY t3.a LIMIT 7
+  --match 45 46 47 48 49 50 51
+  PRAGMA integrity_check;
+  --match ok
+--end
+--task 4
+  SELECT t1.a FROM t1, t2
+   WHERE t2.b GLOB 'x3?y' AND t1.b=('x'||(t2.a+3)||'y')
+   ORDER BY t1.a LIMIT 4
+  --match 33 34 35 36
+  SELECT t3.a FROM t3, t4
+   WHERE t4.b GLOB 'x4?y' AND t3.b=('x'||(t4.a+5)||'y')
+   ORDER BY t3.a LIMIT 7
+  --match 45 46 47 48 49 50 51
+  PRAGMA integrity_check;
+  --match ok
+--end
+--wait all

sqlite3vfs/tests/speedtest1/speedtest1_test.go

@@ -0,0 +1,85 @@
+package speedtest1
+
+import (
+	"bytes"
+	"context"
+	"crypto/rand"
+	"io"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"strings"
+	"testing"
+
+	_ "embed"
+
+	"github.com/tetratelabs/wazero"
+	"github.com/tetratelabs/wazero/imports/wasi_snapshot_preview1"
+
+	"github.com/ncruces/go-sqlite3/sqlite3vfs"
+)
+
+//go:embed testdata/speedtest1.wasm
+var binary []byte
+
+var (
+	rt      wazero.Runtime
+	module  wazero.CompiledModule
+	output  bytes.Buffer
+	options []string
+)
+
+func init() {
+	ctx := context.TODO()
+
+	rt = wazero.NewRuntime(ctx)
+	wasi_snapshot_preview1.MustInstantiate(ctx, rt)
+	env := sqlite3vfs.ExportHostFunctions(rt.NewHostModuleBuilder("env"))
+	_, err := env.Instantiate(ctx)
+	if err != nil {
+		panic(err)
+	}
+
+	module, err = rt.CompileModule(ctx, binary)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func TestMain(m *testing.M) {
+	i := 1
+	options = append(options, "speedtest1")
+	for _, arg := range os.Args[1:] {
+		if strings.HasPrefix(arg, "-test.") {
+			os.Args[i] = arg
+			i++
+		} else {
+			options = append(options, arg)
+		}
+	}
+	os.Args = os.Args[:i]
+
+	code := m.Run()
+	io.Copy(os.Stderr, &output)
+	os.Exit(code)
+}
+
+func Benchmark_speedtest1(b *testing.B) {
+	output.Reset()
+	ctx, vfs := sqlite3vfs.NewContext(context.Background())
+	name := filepath.Join(b.TempDir(), "test.db")
+	args := append(options, "--size", strconv.Itoa(b.N), name)
+	cfg := wazero.NewModuleConfig().
+		WithArgs(args...).WithName("speedtest1").
+		WithStdout(&output).WithStderr(&output).
+		WithSysWalltime().WithSysNanotime().WithSysNanosleep().
+		WithOsyield(runtime.Gosched).
+		WithRandSource(rand.Reader)
+	mod, err := rt.InstantiateModule(ctx, module, cfg)
+	if err != nil {
+		b.Error(err)
+	}
+	mod.Close(ctx)
+	vfs.Close()
+}

sqlite3vfs/tests/speedtest1/testdata/.gitattributes

@@ -0,0 +1 @@
+speedtest1.wasm filter=lfs diff=lfs merge=lfs -text

sqlite3vfs/tests/speedtest1/testdata/.gitignore

@@ -0,0 +1 @@
+speedtest1.c

sqlite3vfs/tests/speedtest1/testdata/build.sh

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+cd -P -- "$(dirname -- "$0")"
+
+ROOT=../../../../
+BINARYEN="$ROOT/tools/binaryen-version_112/bin"
+WASI_SDK="$ROOT/tools/wasi-sdk-20.0/bin"
+
+"$WASI_SDK/clang" --target=wasm32-wasi -flto -g0 -O2 \
+	-o speedtest1.wasm main.c \
+	-I"$ROOT/sqlite3" \
+	-mmutable-globals \
+	-mbulk-memory -mreference-types \
+	-mnontrapping-fptoint -msign-ext \
+	-Wl,--stack-first \
+	-Wl,--import-undefined
+
+"$BINARYEN/wasm-opt" -g -O2 speedtest1.wasm -o speedtest1.tmp \
+	--enable-multivalue --enable-mutable-globals \
+	--enable-bulk-memory --enable-reference-types \
+	--enable-nontrapping-float-to-int --enable-sign-ext
+mv speedtest1.tmp speedtest1.wasm

sqlite3vfs/tests/speedtest1/testdata/main.c

@@ -0,0 +1,12 @@
+#include <stdbool.h>
+#include <stddef.h>
+
+// Configuration
+#include "sqlite_cfg.h"
+// Amalgamation
+#include "sqlite3.c"
+// VFS
+#include "vfs.c"
+
+#define randomFunc(args...) randomFunc2(args)
+#include "speedtest1.c"

sqlite3vfs/tests/speedtest1/testdata/speedtest1.wasm

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:2638f5458f93b60f97006456f60e3e294cffb9ac22b20dba748fbd12e34f056d
+size 1515841

sqlite3vfs/vfs.go

@@ -0,0 +1,366 @@
+package sqlite3vfs
+
+import (
+	"context"
+	"crypto/rand"
+	"io"
+	"reflect"
+	"time"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
+	"github.com/ncruces/julianday"
+	"github.com/tetratelabs/wazero"
+	"github.com/tetratelabs/wazero/api"
+)
+
+// ExportHostFunctions registers the required VFS host functions
+// with the provided env module.
+//
+// Users of the [github.com/ncruces/go-sqlite3] package need not call this directly.
+func ExportHostFunctions(env wazero.HostModuleBuilder) wazero.HostModuleBuilder {
+	util.ExportFuncII(env, "go_vfs_find", vfsFind)
+	util.ExportFuncIIJ(env, "go_localtime", vfsLocaltime)
+	util.ExportFuncIIII(env, "go_randomness", vfsRandomness)
+	util.ExportFuncIII(env, "go_sleep", vfsSleep)
+	util.ExportFuncIII(env, "go_current_time", vfsCurrentTime)
+	util.ExportFuncIII(env, "go_current_time_64", vfsCurrentTime64)
+	util.ExportFuncIIIII(env, "go_full_pathname", vfsFullPathname)
+	util.ExportFuncIIII(env, "go_delete", vfsDelete)
+	util.ExportFuncIIIII(env, "go_access", vfsAccess)
+	util.ExportFuncIIIIII(env, "go_open", vfsOpen)
+	util.ExportFuncII(env, "go_close", vfsClose)
+	util.ExportFuncIIIIJ(env, "go_read", vfsRead)
+	util.ExportFuncIIIIJ(env, "go_write", vfsWrite)
+	util.ExportFuncIIJ(env, "go_truncate", vfsTruncate)
+	util.ExportFuncIII(env, "go_sync", vfsSync)
+	util.ExportFuncIII(env, "go_file_size", vfsFileSize)
+	util.ExportFuncIIII(env, "go_file_control", vfsFileControl)
+	util.ExportFuncII(env, "go_sector_size", vfsSectorSize)
+	util.ExportFuncII(env, "go_device_characteristics", vfsDeviceCharacteristics)
+	util.ExportFuncIII(env, "go_lock", vfsLock)
+	util.ExportFuncIII(env, "go_unlock", vfsUnlock)
+	util.ExportFuncIII(env, "go_check_reserved_lock", vfsCheckReservedLock)
+	return env
+}
+
+type vfsKey struct{}
+type vfsState struct {
+	files []File
+}
+
+// NewContext creates a new context to hold [api.Module] specific VFS data.
+//
+// This context should be passed to any [api.Function] calls that might
+// generate VFS host callbacks.
+//
+// The returned [io.Closer] should be closed after the [api.Module] is closed,
+// to release any associated resources.
+//
+// Users of the [github.com/ncruces/go-sqlite3] package need not call this directly.
+func NewContext(ctx context.Context) (context.Context, io.Closer) {
+	vfs := &vfsState{}
+	return context.WithValue(ctx, vfsKey{}, vfs), vfs
+}
+
+func (vfs *vfsState) Close() error {
+	for _, f := range vfs.files {
+		if f != nil {
+			f.Close()
+		}
+	}
+	vfs.files = nil
+	return nil
+}
+
+func vfsFind(ctx context.Context, mod api.Module, zVfsName uint32) uint32 {
+	name := util.ReadString(mod, zVfsName, _MAX_STRING)
+	if Find(name) != nil {
+		return 1
+	}
+	return 0
+}
+
+func vfsLocaltime(ctx context.Context, mod api.Module, pTm uint32, t int64) _ErrorCode {
+	tm := time.Unix(t, 0)
+	var isdst int
+	if tm.IsDST() {
+		isdst = 1
+	}
+
+	const size = 32 / 8
+	// https://pubs.opengroup.org/onlinepubs/7908799/xsh/time.h.html
+	util.WriteUint32(mod, pTm+0*size, uint32(tm.Second()))
+	util.WriteUint32(mod, pTm+1*size, uint32(tm.Minute()))
+	util.WriteUint32(mod, pTm+2*size, uint32(tm.Hour()))
+	util.WriteUint32(mod, pTm+3*size, uint32(tm.Day()))
+	util.WriteUint32(mod, pTm+4*size, uint32(tm.Month()-time.January))
+	util.WriteUint32(mod, pTm+5*size, uint32(tm.Year()-1900))
+	util.WriteUint32(mod, pTm+6*size, uint32(tm.Weekday()-time.Sunday))
+	util.WriteUint32(mod, pTm+7*size, uint32(tm.YearDay()-1))
+	util.WriteUint32(mod, pTm+8*size, uint32(isdst))
+	return _OK
+}
+
+func vfsRandomness(ctx context.Context, mod api.Module, pVfs, nByte, zByte uint32) uint32 {
+	mem := util.View(mod, zByte, uint64(nByte))
+	n, _ := rand.Reader.Read(mem)
+	return uint32(n)
+}
+
+func vfsSleep(ctx context.Context, mod api.Module, pVfs, nMicro uint32) _ErrorCode {
+	time.Sleep(time.Duration(nMicro) * time.Microsecond)
+	return _OK
+}
+
+func vfsCurrentTime(ctx context.Context, mod api.Module, pVfs, prNow uint32) _ErrorCode {
+	day := julianday.Float(time.Now())
+	util.WriteFloat64(mod, prNow, day)
+	return _OK
+}
+
+func vfsCurrentTime64(ctx context.Context, mod api.Module, pVfs, piNow uint32) _ErrorCode {
+	day, nsec := julianday.Date(time.Now())
+	msec := day*86_400_000 + nsec/1_000_000
+	util.WriteUint64(mod, piNow, uint64(msec))
+	return _OK
+}
+
+func vfsFullPathname(ctx context.Context, mod api.Module, pVfs, zRelative, nFull, zFull uint32) _ErrorCode {
+	vfs := vfsGet(mod, pVfs)
+	path := util.ReadString(mod, zRelative, _MAX_PATHNAME)
+
+	path, err := vfs.FullPathname(path)
+
+	size := uint64(len(path) + 1)
+	if size > uint64(nFull) {
+		return _CANTOPEN_FULLPATH
+	}
+	mem := util.View(mod, zFull, size)
+	mem[len(path)] = 0
+	copy(mem, path)
+
+	return vfsErrorCode(err, _CANTOPEN_FULLPATH)
+}
+
+func vfsDelete(ctx context.Context, mod api.Module, pVfs, zPath, syncDir uint32) _ErrorCode {
+	vfs := vfsGet(mod, pVfs)
+	path := util.ReadString(mod, zPath, _MAX_PATHNAME)
+
+	err := vfs.Delete(path, syncDir != 0)
+	return vfsErrorCode(err, _IOERR_DELETE)
+}
+
+func vfsAccess(ctx context.Context, mod api.Module, pVfs, zPath uint32, flags AccessFlag, pResOut uint32) _ErrorCode {
+	vfs := vfsGet(mod, pVfs)
+	path := util.ReadString(mod, zPath, _MAX_PATHNAME)
+
+	ok, err := vfs.Access(path, flags)
+	var res uint32
+	if ok {
+		res = 1
+	}
+
+	util.WriteUint32(mod, pResOut, res)
+	return vfsErrorCode(err, _IOERR_ACCESS)
+}
+
+func vfsOpen(ctx context.Context, mod api.Module, pVfs, zPath, pFile uint32, flags OpenFlag, pOutFlags uint32) _ErrorCode {
+	vfs := vfsGet(mod, pVfs)
+
+	var path string
+	if zPath != 0 {
+		path = util.ReadString(mod, zPath, _MAX_PATHNAME)
+	}
+
+	file, flags, err := vfs.Open(path, flags)
+	if err != nil {
+		return vfsErrorCode(err, _CANTOPEN)
+	}
+
+	vfsFileRegister(ctx, mod, pFile, file)
+	if pOutFlags != 0 {
+		util.WriteUint32(mod, pOutFlags, uint32(flags))
+	}
+	return _OK
+}
+
+func vfsClose(ctx context.Context, mod api.Module, pFile uint32) _ErrorCode {
+	err := vfsFileClose(ctx, mod, pFile)
+	if err != nil {
+		return _IOERR_CLOSE
+	}
+	return _OK
+}
+
+func vfsRead(ctx context.Context, mod api.Module, pFile, zBuf, iAmt uint32, iOfst int64) _ErrorCode {
+	file := vfsFileGet(ctx, mod, pFile)
+	buf := util.View(mod, zBuf, uint64(iAmt))
+
+	n, err := file.ReadAt(buf, iOfst)
+	if n == int(iAmt) {
+		return _OK
+	}
+	if n == 0 && err != io.EOF {
+		return _IOERR_READ
+	}
+	for i := range buf[n:] {
+		buf[n+i] = 0
+	}
+	return _IOERR_SHORT_READ
+}
+
+func vfsWrite(ctx context.Context, mod api.Module, pFile, zBuf, iAmt uint32, iOfst int64) _ErrorCode {
+	file := vfsFileGet(ctx, mod, pFile)
+	buf := util.View(mod, zBuf, uint64(iAmt))
+
+	_, err := file.WriteAt(buf, iOfst)
+	if err != nil {
+		return _IOERR_WRITE
+	}
+	return _OK
+}
+
+func vfsTruncate(ctx context.Context, mod api.Module, pFile uint32, nByte int64) _ErrorCode {
+	file := vfsFileGet(ctx, mod, pFile)
+	err := file.Truncate(nByte)
+	return vfsErrorCode(err, _IOERR_TRUNCATE)
+}
+
+func vfsSync(ctx context.Context, mod api.Module, pFile uint32, flags SyncFlag) _ErrorCode {
+	file := vfsFileGet(ctx, mod, pFile)
+	err := file.Sync(flags)
+	return vfsErrorCode(err, _IOERR_FSYNC)
+}
+
+func vfsFileSize(ctx context.Context, mod api.Module, pFile, pSize uint32) _ErrorCode {
+	file := vfsFileGet(ctx, mod, pFile)
+	size, err := file.FileSize()
+	util.WriteUint64(mod, pSize, uint64(size))
+	return vfsErrorCode(err, _IOERR_SEEK)
+}
+
+func vfsLock(ctx context.Context, mod api.Module, pFile uint32, eLock LockLevel) _ErrorCode {
+	file := vfsFileGet(ctx, mod, pFile)
+	err := file.Lock(eLock)
+	return vfsErrorCode(err, _IOERR_LOCK)
+}
+
+func vfsUnlock(ctx context.Context, mod api.Module, pFile uint32, eLock LockLevel) _ErrorCode {
+	file := vfsFileGet(ctx, mod, pFile)
+	err := file.Unlock(eLock)
+	return vfsErrorCode(err, _IOERR_UNLOCK)
+}
+
+func vfsCheckReservedLock(ctx context.Context, mod api.Module, pFile, pResOut uint32) _ErrorCode {
+	file := vfsFileGet(ctx, mod, pFile)
+	locked, err := file.CheckReservedLock()
+
+	var res uint32
+	if locked {
+		res = 1
+	}
+
+	util.WriteUint32(mod, pResOut, res)
+	return vfsErrorCode(err, _IOERR_CHECKRESERVEDLOCK)
+}
+
+func vfsFileControl(ctx context.Context, mod api.Module, pFile uint32, op _FcntlOpcode, pArg uint32) _ErrorCode {
+	file := vfsFileGet(ctx, mod, pFile)
+
+	switch op {
+	case _FCNTL_LOCKSTATE:
+		if file, ok := file.(FileLockState); ok {
+			util.WriteUint32(mod, pArg, uint32(file.LockState()))
+			return _OK
+		}
+
+	case _FCNTL_LOCK_TIMEOUT:
+		if file, ok := file.(*vfsFile); ok {
+			millis := file.lockTimeout.Milliseconds()
+			file.lockTimeout = time.Duration(util.ReadUint32(mod, pArg)) * time.Millisecond
+			util.WriteUint32(mod, pArg, uint32(millis))
+			return _OK
+		}
+
+	case _FCNTL_POWERSAFE_OVERWRITE:
+		if file, ok := file.(FilePowersafeOverwrite); ok {
+			switch util.ReadUint32(mod, pArg) {
+			case 0:
+				file.SetPowersafeOverwrite(false)
+			case 1:
+				file.SetPowersafeOverwrite(true)
+			default:
+				if file.PowersafeOverwrite() {
+					util.WriteUint32(mod, pArg, 1)
+				} else {
+					util.WriteUint32(mod, pArg, 0)
+				}
+			}
+			return _OK
+		}
+
+	case _FCNTL_SIZE_HINT:
+		if file, ok := file.(FileSizeHint); ok {
+			size := util.ReadUint64(mod, pArg)
+			err := file.SizeHint(int64(size))
+			return vfsErrorCode(err, _IOERR_TRUNCATE)
+		}
+
+	case _FCNTL_HAS_MOVED:
+		if file, ok := file.(FileHasMoved); ok {
+			moved, err := file.HasMoved()
+
+			var res uint32
+			if moved {
+				res = 1
+			}
+
+			util.WriteUint32(mod, pArg, res)
+			return vfsErrorCode(err, _IOERR_FSTAT)
+		}
+	}
+
+	// Consider also implementing these opcodes (in use by SQLite):
+	//  _FCNTL_BUSYHANDLER
+	//  _FCNTL_COMMIT_PHASETWO
+	//  _FCNTL_PDB
+	//  _FCNTL_PRAGMA
+	//  _FCNTL_SYNC
+	return _NOTFOUND
+}
+
+func vfsSectorSize(ctx context.Context, mod api.Module, pFile uint32) uint32 {
+	file := vfsFileGet(ctx, mod, pFile)
+	return uint32(file.SectorSize())
+}
+
+func vfsDeviceCharacteristics(ctx context.Context, mod api.Module, pFile uint32) DeviceCharacteristic {
+	file := vfsFileGet(ctx, mod, pFile)
+	return file.DeviceCharacteristics()
+}
+
+func vfsGet(mod api.Module, pVfs uint32) VFS {
+	if pVfs == 0 {
+		return vfsOS{}
+	}
+	const zNameOffset = 16
+	name := util.ReadString(mod, util.ReadUint32(mod, pVfs+zNameOffset), _MAX_STRING)
+	if name == "os" {
+		return vfsOS{}
+	}
+	if vfs := Find(name); vfs != nil {
+		return vfs
+	}
+	panic(util.NoVFSErr + util.ErrorString(name))
+}
+
+func vfsErrorCode(err error, def _ErrorCode) _ErrorCode {
+	if err == nil {
+		return _OK
+	}
+	switch v := reflect.ValueOf(err); v.Kind() {
+	case reflect.Uint8, reflect.Uint16, reflect.Uint32:
+		return _ErrorCode(v.Uint())
+	}
+	return def
+}

sqlite3vfs/vfs_api.go

@@ -0,0 +1,109 @@
+// Package sqlite3vfs wraps the C SQLite VFS API.
+package sqlite3vfs
+
+import "sync"
+
+// A VFS defines the interface between the SQLite core and the underlying operating system.
+//
+// Use sqlite3.ErrorCode or sqlite3.ExtendedErrorCode to return specific error codes.
+//
+// https://www.sqlite.org/c3ref/vfs.html
+type VFS interface {
+	Open(name string, flags OpenFlag) (File, OpenFlag, error)
+	Delete(name string, syncDir bool) error
+	Access(name string, flags AccessFlag) (bool, error)
+	FullPathname(name string) (string, error)
+}
+
+// A File represents an open file in the OS interface layer.
+//
+// Use sqlite3.ErrorCode or sqlite3.ExtendedErrorCode to return specific error codes.
+// In particular, sqlite3.BUSY is necessary to correctly implement lock methods.
+//
+// https://www.sqlite.org/c3ref/io_methods.html
+type File interface {
+	Close() error
+	ReadAt(p []byte, off int64) (n int, err error)
+	WriteAt(p []byte, off int64) (n int, err error)
+	Truncate(size int64) error
+	Sync(flags SyncFlag) error
+	FileSize() (int64, error)
+	Lock(lock LockLevel) error
+	Unlock(lock LockLevel) error
+	CheckReservedLock() (bool, error)
+	SectorSize() int
+	DeviceCharacteristics() DeviceCharacteristic
+}
+
+// FileLockState extends [File] to implement the
+// SQLITE_FCNTL_LOCKSTATE file control opcode.
+//
+// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html
+type FileLockState interface {
+	File
+	LockState() LockLevel
+}
+
+// FileLockState extends [File] to implement the
+// SQLITE_FCNTL_SIZE_HINT file control opcode.
+//
+// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html
+type FileSizeHint interface {
+	File
+	SizeHint(size int64) error
+}
+
+// FileLockState extends [File] to implement the
+// SQLITE_FCNTL_HAS_MOVED file control opcode.
+//
+// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html
+type FileHasMoved interface {
+	File
+	HasMoved() (bool, error)
+}
+
+// FileLockState extends [File] to implement the
+// SQLITE_FCNTL_POWERSAFE_OVERWRITE file control opcode.
+//
+// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html
+type FilePowersafeOverwrite interface {
+	File
+	PowersafeOverwrite() bool
+	SetPowersafeOverwrite(bool)
+}
+
+var (
+	vfsRegistry    map[string]VFS
+	vfsRegistryMtx sync.Mutex
+)
+
+// Find returns a VFS given its name.
+// If there is no match, nil is returned.
+//
+// https://www.sqlite.org/c3ref/vfs_find.html
+func Find(name string) VFS {
+	vfsRegistryMtx.Lock()
+	defer vfsRegistryMtx.Unlock()
+	return vfsRegistry[name]
+}
+
+// Register registers a VFS.
+//
+// https://www.sqlite.org/c3ref/vfs_find.html
+func Register(name string, vfs VFS) {
+	vfsRegistryMtx.Lock()
+	defer vfsRegistryMtx.Unlock()
+	if vfsRegistry == nil {
+		vfsRegistry = map[string]VFS{}
+	}
+	vfsRegistry[name] = vfs
+}
+
+// Unregister unregisters a VFS.
+//
+// https://www.sqlite.org/c3ref/vfs_find.html
+func Unregister(name string) {
+	vfsRegistryMtx.Lock()
+	defer vfsRegistryMtx.Unlock()
+	delete(vfsRegistry, name)
+}

sqlite3vfs/vfs_api_test.go

@@ -0,0 +1,48 @@
+package sqlite3vfs_test
+
+import (
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	"github.com/ncruces/go-sqlite3/sqlite3vfs"
+)
+
+type testVFS struct {
+	*testing.T
+}
+
+func (t testVFS) Open(name string, flags sqlite3vfs.OpenFlag) (sqlite3vfs.File, sqlite3vfs.OpenFlag, error) {
+	t.Log("Open", name, flags)
+	t.SkipNow()
+	return nil, flags, nil
+}
+
+func (t testVFS) Delete(name string, syncDir bool) error {
+	t.Log("Delete", name, syncDir)
+	return nil
+}
+
+func (t testVFS) Access(name string, flags sqlite3vfs.AccessFlag) (bool, error) {
+	t.Log("Access", name, flags)
+	return true, nil
+}
+
+func (t testVFS) FullPathname(name string) (string, error) {
+	t.Log("FullPathname", name)
+	return name, nil
+}
+
+func TestRegister(t *testing.T) {
+	vfs := testVFS{t}
+	sqlite3vfs.Register("foo", vfs)
+	defer sqlite3vfs.Unregister("foo")
+
+	conn, err := sqlite3.Open("file:file.db?vfs=foo")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer conn.Close()
+
+	t.Error("want skip")
+}

sqlite3vfs/vfs_file.go

@@ -0,0 +1,223 @@
+package sqlite3vfs
+
+import (
+	"context"
+	"errors"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"runtime"
+	"time"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
+	"github.com/tetratelabs/wazero/api"
+)
+
+type vfsOS struct{}
+
+func (vfsOS) FullPathname(path string) (string, error) {
+	path, err := filepath.Abs(path)
+	if err != nil {
+		return "", err
+	}
+	fi, err := os.Lstat(path)
+	if err != nil {
+		if errors.Is(err, fs.ErrNotExist) {
+			return path, nil
+		}
+		return "", err
+	}
+	if fi.Mode()&fs.ModeSymlink != 0 {
+		err = _OK_SYMLINK
+	}
+	return path, err
+}
+
+func (vfsOS) Delete(path string, syncDir bool) error {
+	err := os.Remove(path)
+	if errors.Is(err, fs.ErrNotExist) {
+		return _IOERR_DELETE_NOENT
+	}
+	if err != nil {
+		return err
+	}
+	if runtime.GOOS != "windows" && syncDir {
+		f, err := os.Open(filepath.Dir(path))
+		if err != nil {
+			return _OK
+		}
+		defer f.Close()
+		err = osSync(f, false, false)
+		if err != nil {
+			return _IOERR_DIR_FSYNC
+		}
+	}
+	return nil
+}
+
+func (vfsOS) Access(name string, flags AccessFlag) (bool, error) {
+	err := osAccess(name, flags)
+	if flags == ACCESS_EXISTS {
+		if errors.Is(err, fs.ErrNotExist) {
+			return false, nil
+		}
+	} else {
+		if errors.Is(err, fs.ErrPermission) {
+			return false, nil
+		}
+	}
+	return err == nil, err
+}
+
+func (vfsOS) Open(name string, flags OpenFlag) (File, OpenFlag, error) {
+	var oflags int
+	if flags&OPEN_EXCLUSIVE != 0 {
+		oflags |= os.O_EXCL
+	}
+	if flags&OPEN_CREATE != 0 {
+		oflags |= os.O_CREATE
+	}
+	if flags&OPEN_READONLY != 0 {
+		oflags |= os.O_RDONLY
+	}
+	if flags&OPEN_READWRITE != 0 {
+		oflags |= os.O_RDWR
+	}
+
+	var err error
+	var f *os.File
+	if name == "" {
+		f, err = os.CreateTemp("", "*.db")
+	} else {
+		f, err = osOpenFile(name, oflags, 0666)
+	}
+	if err != nil {
+		return nil, flags, err
+	}
+
+	if flags&OPEN_DELETEONCLOSE != 0 {
+		os.Remove(f.Name())
+	}
+
+	file := vfsFile{
+		File:     f,
+		psow:     true,
+		readOnly: flags&OPEN_READONLY != 0,
+		syncDir: runtime.GOOS != "windows" &&
+			flags&(OPEN_CREATE) != 0 &&
+			flags&(OPEN_MAIN_JOURNAL|OPEN_SUPER_JOURNAL|OPEN_WAL) != 0,
+	}
+	return &file, flags, nil
+}
+
+type vfsFile struct {
+	*os.File
+	lockTimeout time.Duration
+	lock        LockLevel
+	psow        bool
+	syncDir     bool
+	readOnly    bool
+}
+
+var (
+	// Ensure these interfaces are implemented:
+	_ FileLockState          = &vfsFile{}
+	_ FileHasMoved           = &vfsFile{}
+	_ FileSizeHint           = &vfsFile{}
+	_ FilePowersafeOverwrite = &vfsFile{}
+)
+
+func vfsFileNew(vfs *vfsState, file File) uint32 {
+	// Find an empty slot.
+	for id, f := range vfs.files {
+		if f == nil {
+			vfs.files[id] = file
+			return uint32(id)
+		}
+	}
+
+	// Add a new slot.
+	vfs.files = append(vfs.files, file)
+	return uint32(len(vfs.files) - 1)
+}
+
+func vfsFileRegister(ctx context.Context, mod api.Module, pFile uint32, file File) {
+	const fileHandleOffset = 4
+	id := vfsFileNew(ctx.Value(vfsKey{}).(*vfsState), file)
+	util.WriteUint32(mod, pFile+fileHandleOffset, id)
+}
+
+func vfsFileGet(ctx context.Context, mod api.Module, pFile uint32) File {
+	const fileHandleOffset = 4
+	vfs := ctx.Value(vfsKey{}).(*vfsState)
+	id := util.ReadUint32(mod, pFile+fileHandleOffset)
+	return vfs.files[id]
+}
+
+func vfsFileClose(ctx context.Context, mod api.Module, pFile uint32) error {
+	const fileHandleOffset = 4
+	vfs := ctx.Value(vfsKey{}).(*vfsState)
+	id := util.ReadUint32(mod, pFile+fileHandleOffset)
+	file := vfs.files[id]
+	vfs.files[id] = nil
+	return file.Close()
+}
+
+func (f *vfsFile) Sync(flags SyncFlag) error {
+	dataonly := (flags & SYNC_DATAONLY) != 0
+	fullsync := (flags & 0x0f) == SYNC_FULL
+
+	err := osSync(f.File, fullsync, dataonly)
+	if err != nil {
+		return err
+	}
+	if runtime.GOOS != "windows" && f.syncDir {
+		f.syncDir = false
+		d, err := os.Open(filepath.Dir(f.File.Name()))
+		if err != nil {
+			return nil
+		}
+		defer d.Close()
+		err = osSync(d, false, false)
+		if err != nil {
+			return _IOERR_DIR_FSYNC
+		}
+	}
+	return nil
+}
+
+func (f *vfsFile) FileSize() (int64, error) {
+	return f.Seek(0, io.SeekEnd)
+}
+
+func (*vfsFile) SectorSize() int {
+	return _DEFAULT_SECTOR_SIZE
+}
+
+func (f *vfsFile) DeviceCharacteristics() DeviceCharacteristic {
+	if f.psow {
+		return IOCAP_POWERSAFE_OVERWRITE
+	}
+	return 0
+}
+
+func (f *vfsFile) SizeHint(size int64) error {
+	return osAllocate(f.File, size)
+}
+
+func (f *vfsFile) HasMoved() (bool, error) {
+	fi, err := f.Stat()
+	if err != nil {
+		return false, err
+	}
+	pi, err := os.Stat(f.Name())
+	if err != nil && !errors.Is(err, fs.ErrNotExist) {
+		return false, err
+	}
+	return !os.SameFile(fi, pi), nil
+}
+
+func (f *vfsFile) LockState() LockLevel            { return f.lock }
+func (f *vfsFile) PowersafeOverwrite() bool        { return f.psow }
+func (f *vfsFile) SetPowersafeOverwrite(psow bool) { f.psow = psow }

sqlite3vfs/vfs_lock.go

@@ -0,0 +1,150 @@
+package sqlite3vfs
+
+import (
+	"os"
+	"time"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
+)
+
+const (
+	_PENDING_BYTE  = 0x40000000
+	_RESERVED_BYTE = (_PENDING_BYTE + 1)
+	_SHARED_FIRST  = (_PENDING_BYTE + 2)
+	_SHARED_SIZE   = 510
+)
+
+func (file *vfsFile) Lock(eLock LockLevel) error {
+	// Argument check. SQLite never explicitly requests a pending lock.
+	if eLock != LOCK_SHARED && eLock != LOCK_RESERVED && eLock != LOCK_EXCLUSIVE {
+		panic(util.AssertErr())
+	}
+
+	switch {
+	case file.lock < LOCK_NONE || file.lock > LOCK_EXCLUSIVE:
+		// Connection state check.
+		panic(util.AssertErr())
+	case file.lock == LOCK_NONE && eLock > LOCK_SHARED:
+		// We never move from unlocked to anything higher than a shared lock.
+		panic(util.AssertErr())
+	case file.lock != LOCK_SHARED && eLock == LOCK_RESERVED:
+		// A shared lock is always held when a reserved lock is requested.
+		panic(util.AssertErr())
+	}
+
+	// If we already have an equal or more restrictive lock, do nothing.
+	if file.lock >= eLock {
+		return nil
+	}
+
+	// Do not allow any kind of write-lock on a read-only database.
+	if file.readOnly && eLock >= LOCK_RESERVED {
+		return _IOERR_LOCK
+	}
+
+	switch eLock {
+	case LOCK_SHARED:
+		// Must be unlocked to get SHARED.
+		if file.lock != LOCK_NONE {
+			panic(util.AssertErr())
+		}
+		if rc := osGetSharedLock(file.File, file.lockTimeout); rc != _OK {
+			return rc
+		}
+		file.lock = LOCK_SHARED
+		return nil
+
+	case LOCK_RESERVED:
+		// Must be SHARED to get RESERVED.
+		if file.lock != LOCK_SHARED {
+			panic(util.AssertErr())
+		}
+		if rc := osGetReservedLock(file.File, file.lockTimeout); rc != _OK {
+			return rc
+		}
+		file.lock = LOCK_RESERVED
+		return nil
+
+	case LOCK_EXCLUSIVE:
+		// Must be SHARED, RESERVED or PENDING to get EXCLUSIVE.
+		if file.lock <= LOCK_NONE || file.lock >= LOCK_EXCLUSIVE {
+			panic(util.AssertErr())
+		}
+		// A PENDING lock is needed before acquiring an EXCLUSIVE lock.
+		if file.lock < LOCK_PENDING {
+			if rc := osGetPendingLock(file.File); rc != _OK {
+				return rc
+			}
+			file.lock = LOCK_PENDING
+		}
+		if rc := osGetExclusiveLock(file.File, file.lockTimeout); rc != _OK {
+			return rc
+		}
+		file.lock = LOCK_EXCLUSIVE
+		return nil
+
+	default:
+		panic(util.AssertErr())
+	}
+}
+
+func (file *vfsFile) Unlock(eLock LockLevel) error {
+	// Argument check.
+	if eLock != LOCK_NONE && eLock != LOCK_SHARED {
+		panic(util.AssertErr())
+	}
+
+	// Connection state check.
+	if file.lock < LOCK_NONE || file.lock > LOCK_EXCLUSIVE {
+		panic(util.AssertErr())
+	}
+
+	// If we don't have a more restrictive lock, do nothing.
+	if file.lock <= eLock {
+		return nil
+	}
+
+	switch eLock {
+	case LOCK_SHARED:
+		if rc := osDowngradeLock(file.File, file.lock); rc != _OK {
+			return rc
+		}
+		file.lock = LOCK_SHARED
+		return nil
+
+	case LOCK_NONE:
+		rc := osReleaseLock(file.File, file.lock)
+		file.lock = LOCK_NONE
+		return rc
+
+	default:
+		panic(util.AssertErr())
+	}
+}
+
+func (file *vfsFile) CheckReservedLock() (bool, error) {
+	// Connection state check.
+	if file.lock < LOCK_NONE || file.lock > LOCK_EXCLUSIVE {
+		panic(util.AssertErr())
+	}
+
+	if file.lock >= LOCK_RESERVED {
+		return true, nil
+	}
+	return osCheckReservedLock(file.File)
+}
+
+func osGetReservedLock(file *os.File, timeout time.Duration) _ErrorCode {
+	// Acquire the RESERVED lock.
+	return osWriteLock(file, _RESERVED_BYTE, 1, timeout)
+}
+
+func osGetPendingLock(file *os.File) _ErrorCode {
+	// Acquire the PENDING lock.
+	return osWriteLock(file, _PENDING_BYTE, 1, 0)
+}
+
+func osCheckReservedLock(file *os.File) (bool, _ErrorCode) {
+	// Test the RESERVED lock.
+	return osCheckLock(file, _RESERVED_BYTE, 1)
+}

sqlite3vfs/vfs_lock_test.go

@@ -0,0 +1,219 @@
+package sqlite3vfs
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"runtime"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
+)
+
+func Test_vfsLock(t *testing.T) {
+	switch runtime.GOOS {
+	case "linux", "darwin", "windows":
+		break
+	default:
+		t.Skip("OS lacks OFD locks")
+	}
+
+	name := filepath.Join(t.TempDir(), "test.db")
+
+	// Create a temporary file.
+	file1, err := os.OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0666)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer file1.Close()
+
+	// Open the temporary file again.
+	file2, err := os.OpenFile(name, os.O_RDWR, 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer file2.Close()
+
+	const (
+		pFile1  = 4
+		pFile2  = 16
+		pOutput = 32
+	)
+	mod := util.NewMockModule(128)
+	ctx, vfs := NewContext(context.TODO())
+	defer vfs.Close()
+
+	vfsFileRegister(ctx, mod, pFile1, &vfsFile{File: file1})
+	vfsFileRegister(ctx, mod, pFile2, &vfsFile{File: file2})
+
+	rc := vfsCheckReservedLock(ctx, mod, pFile1, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got != 0 {
+		t.Error("file was locked")
+	}
+	rc = vfsCheckReservedLock(ctx, mod, pFile2, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got != 0 {
+		t.Error("file was locked")
+	}
+	rc = vfsFileControl(ctx, mod, pFile2, _FCNTL_LOCKSTATE, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got != uint32(LOCK_NONE) {
+		t.Error("invalid lock state", got)
+	}
+
+	rc = vfsLock(ctx, mod, pFile2, LOCK_SHARED)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+
+	rc = vfsCheckReservedLock(ctx, mod, pFile1, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got != 0 {
+		t.Error("file was locked")
+	}
+	rc = vfsCheckReservedLock(ctx, mod, pFile2, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got != 0 {
+		t.Error("file was locked")
+	}
+	rc = vfsFileControl(ctx, mod, pFile2, _FCNTL_LOCKSTATE, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got != uint32(LOCK_SHARED) {
+		t.Error("invalid lock state", got)
+	}
+
+	rc = vfsLock(ctx, mod, pFile2, LOCK_RESERVED)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	rc = vfsLock(ctx, mod, pFile2, LOCK_SHARED)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+
+	rc = vfsCheckReservedLock(ctx, mod, pFile1, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got == 0 {
+		t.Error("file wasn't locked")
+	}
+	rc = vfsCheckReservedLock(ctx, mod, pFile2, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got == 0 {
+		t.Error("file wasn't locked")
+	}
+	rc = vfsFileControl(ctx, mod, pFile2, _FCNTL_LOCKSTATE, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got != uint32(LOCK_RESERVED) {
+		t.Error("invalid lock state", got)
+	}
+
+	rc = vfsLock(ctx, mod, pFile2, LOCK_EXCLUSIVE)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+
+	rc = vfsCheckReservedLock(ctx, mod, pFile1, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got == 0 {
+		t.Error("file wasn't locked")
+	}
+	rc = vfsCheckReservedLock(ctx, mod, pFile2, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got == 0 {
+		t.Error("file wasn't locked")
+	}
+	rc = vfsFileControl(ctx, mod, pFile2, _FCNTL_LOCKSTATE, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got != uint32(LOCK_EXCLUSIVE) {
+		t.Error("invalid lock state", got)
+	}
+
+	rc = vfsLock(ctx, mod, pFile1, LOCK_SHARED)
+	if rc == _OK {
+		t.Fatal("returned", rc)
+	}
+
+	rc = vfsCheckReservedLock(ctx, mod, pFile1, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got == 0 {
+		t.Error("file wasn't locked")
+	}
+	rc = vfsCheckReservedLock(ctx, mod, pFile2, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got == 0 {
+		t.Error("file wasn't locked")
+	}
+	rc = vfsFileControl(ctx, mod, pFile1, _FCNTL_LOCKSTATE, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got != uint32(LOCK_NONE) {
+		t.Error("invalid lock state", got)
+	}
+
+	rc = vfsUnlock(ctx, mod, pFile2, LOCK_SHARED)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+
+	rc = vfsCheckReservedLock(ctx, mod, pFile1, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got != 0 {
+		t.Error("file was locked")
+	}
+	rc = vfsCheckReservedLock(ctx, mod, pFile2, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got != 0 {
+		t.Error("file was locked")
+	}
+
+	rc = vfsLock(ctx, mod, pFile1, LOCK_SHARED)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	rc = vfsFileControl(ctx, mod, pFile1, _FCNTL_LOCKSTATE, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, pOutput); got != uint32(LOCK_SHARED) {
+		t.Error("invalid lock state", got)
+	}
+
+	rc = vfsFileControl(ctx, mod, pFile1, _FCNTL_LOCK_TIMEOUT, 1)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+}

sqlite3vfs/vfs_os_bsd.go

@@ -0,0 +1,56 @@
+//go:build freebsd || openbsd || netbsd || dragonfly || (darwin && sqlite3_bsd)
+
+package sqlite3vfs
+
+import (
+	"os"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+func osUnlock(file *os.File, start, len int64) _ErrorCode {
+	if start == 0 && len == 0 {
+		err := unix.Flock(int(file.Fd()), unix.LOCK_UN)
+		if err != nil {
+			return _IOERR_UNLOCK
+		}
+	}
+	return _OK
+}
+
+func osLock(file *os.File, how int, timeout time.Duration, def _ErrorCode) _ErrorCode {
+	var err error
+	for {
+		err = unix.Flock(int(file.Fd()), how)
+		if errno, _ := err.(unix.Errno); errno != unix.EAGAIN {
+			break
+		}
+		if timeout < time.Millisecond {
+			break
+		}
+		timeout -= time.Millisecond
+		time.Sleep(time.Millisecond)
+	}
+	return osLockErrorCode(err, def)
+}
+
+func osReadLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
+	return osLock(file, unix.LOCK_SH|unix.LOCK_NB, timeout, _IOERR_RDLOCK)
+}
+
+func osWriteLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
+	return osLock(file, unix.LOCK_EX|unix.LOCK_NB, timeout, _IOERR_LOCK)
+}
+
+func osCheckLock(file *os.File, start, len int64) (bool, _ErrorCode) {
+	lock := unix.Flock_t{
+		Type:  unix.F_RDLCK,
+		Start: start,
+		Len:   len,
+	}
+	if unix.FcntlFlock(file.Fd(), unix.F_GETLK, &lock) != nil {
+		return false, _IOERR_CHECKRESERVEDLOCK
+	}
+	return lock.Type != unix.F_UNLCK, _OK
+}

sqlite3vfs/vfs_os_darwin.go

@@ -0,0 +1,106 @@
+//go:build !sqlite3_bsd
+
+package sqlite3vfs
+
+import (
+	"io"
+	"os"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+const (
+	// https://github.com/apple/darwin-xnu/blob/main/bsd/sys/fcntl.h
+	_F_OFD_SETLK         = 90
+	_F_OFD_SETLKW        = 91
+	_F_OFD_GETLK         = 92
+	_F_OFD_SETLKWTIMEOUT = 93
+)
+
+type flocktimeout_t struct {
+	fl      unix.Flock_t
+	timeout unix.Timespec
+}
+
+func osSync(file *os.File, fullsync, dataonly bool) error {
+	if fullsync {
+		return file.Sync()
+	}
+	return unix.Fsync(int(file.Fd()))
+}
+
+func osAllocate(file *os.File, size int64) error {
+	off, err := file.Seek(0, io.SeekEnd)
+	if err != nil {
+		return err
+	}
+	if size <= off {
+		return nil
+	}
+
+	// https://stackoverflow.com/a/11497568/867786
+	store := unix.Fstore_t{
+		Flags:   unix.F_ALLOCATECONTIG,
+		Posmode: unix.F_PEOFPOSMODE,
+		Offset:  0,
+		Length:  size,
+	}
+
+	// Try to get a continuous chunk of disk space.
+	err = unix.FcntlFstore(file.Fd(), unix.F_PREALLOCATE, &store)
+	if err != nil {
+		// OK, perhaps we are too fragmented, allocate non-continuous.
+		store.Flags = unix.F_ALLOCATEALL
+		unix.FcntlFstore(file.Fd(), unix.F_PREALLOCATE, &store)
+	}
+	return file.Truncate(size)
+}
+
+func osUnlock(file *os.File, start, len int64) _ErrorCode {
+	err := unix.FcntlFlock(file.Fd(), _F_OFD_SETLK, &unix.Flock_t{
+		Type:  unix.F_UNLCK,
+		Start: start,
+		Len:   len,
+	})
+	if err != nil {
+		return _IOERR_UNLOCK
+	}
+	return _OK
+}
+
+func osLock(file *os.File, typ int16, start, len int64, timeout time.Duration, def _ErrorCode) _ErrorCode {
+	lock := flocktimeout_t{fl: unix.Flock_t{
+		Type:  typ,
+		Start: start,
+		Len:   len,
+	}}
+	var err error
+	if timeout == 0 {
+		err = unix.FcntlFlock(file.Fd(), _F_OFD_SETLK, &lock.fl)
+	} else {
+		lock.timeout = unix.NsecToTimespec(int64(timeout / time.Nanosecond))
+		err = unix.FcntlFlock(file.Fd(), _F_OFD_SETLKWTIMEOUT, &lock.fl)
+	}
+	return osLockErrorCode(err, def)
+}
+
+func osReadLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
+	return osLock(file, unix.F_RDLCK, start, len, timeout, _IOERR_RDLOCK)
+}
+
+func osWriteLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
+	return osLock(file, unix.F_WRLCK, start, len, timeout, _IOERR_LOCK)
+}
+
+func osCheckLock(file *os.File, start, len int64) (bool, _ErrorCode) {
+	lock := unix.Flock_t{
+		Type:  unix.F_RDLCK,
+		Start: start,
+		Len:   len,
+	}
+	if unix.FcntlFlock(file.Fd(), _F_OFD_GETLK, &lock) != nil {
+		return false, _IOERR_CHECKRESERVEDLOCK
+	}
+	return lock.Type != unix.F_UNLCK, _OK
+}

sqlite3vfs/vfs_os_linux.go

@@ -0,0 +1,25 @@
+package sqlite3vfs
+
+import (
+	"os"
+
+	"golang.org/x/sys/unix"
+)
+
+func osSync(file *os.File, fullsync, dataonly bool) error {
+	if dataonly {
+		_, _, err := unix.Syscall(unix.SYS_FDATASYNC, file.Fd(), 0, 0)
+		if err != 0 {
+			return err
+		}
+		return nil
+	}
+	return file.Sync()
+}
+
+func osAllocate(file *os.File, size int64) error {
+	if size == 0 {
+		return nil
+	}
+	return unix.Fallocate(int(file.Fd()), 0, 0, size)
+}

sqlite3vfs/vfs_os_ofd.go

@@ -0,0 +1,63 @@
+//go:build linux || illumos
+
+package sqlite3vfs
+
+import (
+	"os"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+func osUnlock(file *os.File, start, len int64) _ErrorCode {
+	err := unix.FcntlFlock(file.Fd(), unix.F_OFD_SETLK, &unix.Flock_t{
+		Type:  unix.F_UNLCK,
+		Start: start,
+		Len:   len,
+	})
+	if err != nil {
+		return _IOERR_UNLOCK
+	}
+	return _OK
+}
+
+func osLock(file *os.File, typ int16, start, len int64, timeout time.Duration, def _ErrorCode) _ErrorCode {
+	lock := unix.Flock_t{
+		Type:  typ,
+		Start: start,
+		Len:   len,
+	}
+	var err error
+	for {
+		err = unix.FcntlFlock(file.Fd(), unix.F_OFD_SETLK, &lock)
+		if errno, _ := err.(unix.Errno); errno != unix.EAGAIN {
+			break
+		}
+		if timeout < time.Millisecond {
+			break
+		}
+		timeout -= time.Millisecond
+		time.Sleep(time.Millisecond)
+	}
+	return osLockErrorCode(err, def)
+}
+
+func osReadLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
+	return osLock(file, unix.F_RDLCK, start, len, timeout, _IOERR_RDLOCK)
+}
+
+func osWriteLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
+	return osLock(file, unix.F_WRLCK, start, len, timeout, _IOERR_LOCK)
+}
+
+func osCheckLock(file *os.File, start, len int64) (bool, _ErrorCode) {
+	lock := unix.Flock_t{
+		Type:  unix.F_RDLCK,
+		Start: start,
+		Len:   len,
+	}
+	if unix.FcntlFlock(file.Fd(), unix.F_OFD_GETLK, &lock) != nil {
+		return false, _IOERR_CHECKRESERVEDLOCK
+	}
+	return lock.Type != unix.F_UNLCK, _OK
+}

sqlite3vfs/vfs_os_other.go

@@ -0,0 +1,23 @@
+//go:build !linux && (!darwin || sqlite3_bsd)
+
+package sqlite3vfs
+
+import (
+	"io"
+	"os"
+)
+
+func osSync(file *os.File, fullsync, dataonly bool) error {
+	return file.Sync()
+}
+
+func osAllocate(file *os.File, size int64) error {
+	off, err := file.Seek(0, io.SeekEnd)
+	if err != nil {
+		return err
+	}
+	if size <= off {
+		return nil
+	}
+	return file.Truncate(size)
+}

sqlite3vfs/vfs_os_unix.go

@@ -0,0 +1,87 @@
+//go:build unix
+
+package sqlite3vfs
+
+import (
+	"io/fs"
+	"os"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+func osOpenFile(name string, flag int, perm fs.FileMode) (*os.File, error) {
+	return os.OpenFile(name, flag, perm)
+}
+
+func osAccess(path string, flags AccessFlag) error {
+	var access uint32 // unix.F_OK
+	switch flags {
+	case ACCESS_READWRITE:
+		access = unix.R_OK | unix.W_OK
+	case ACCESS_READ:
+		access = unix.R_OK
+	}
+	return unix.Access(path, access)
+}
+
+func osGetSharedLock(file *os.File, timeout time.Duration) _ErrorCode {
+	// Test the PENDING lock before acquiring a new SHARED lock.
+	if pending, _ := osCheckLock(file, _PENDING_BYTE, 1); pending {
+		return _BUSY
+	}
+	// Acquire the SHARED lock.
+	return osReadLock(file, _SHARED_FIRST, _SHARED_SIZE, timeout)
+}
+
+func osGetExclusiveLock(file *os.File, timeout time.Duration) _ErrorCode {
+	if timeout == 0 {
+		timeout = time.Millisecond
+	}
+
+	// Acquire the EXCLUSIVE lock.
+	return osWriteLock(file, _SHARED_FIRST, _SHARED_SIZE, timeout)
+}
+
+func osDowngradeLock(file *os.File, state LockLevel) _ErrorCode {
+	if state >= LOCK_EXCLUSIVE {
+		// Downgrade to a SHARED lock.
+		if rc := osReadLock(file, _SHARED_FIRST, _SHARED_SIZE, 0); rc != _OK {
+			// In theory, the downgrade to a SHARED cannot fail because another
+			// process is holding an incompatible lock. If it does, this
+			// indicates that the other process is not following the locking
+			// protocol. If this happens, return _IOERR_RDLOCK. Returning
+			// BUSY would confuse the upper layer.
+			return _IOERR_RDLOCK
+		}
+	}
+	// Release the PENDING and RESERVED locks.
+	return osUnlock(file, _PENDING_BYTE, 2)
+}
+
+func osReleaseLock(file *os.File, _ LockLevel) _ErrorCode {
+	// Release all locks.
+	return osUnlock(file, 0, 0)
+}
+
+func osLockErrorCode(err error, def _ErrorCode) _ErrorCode {
+	if err == nil {
+		return _OK
+	}
+	if errno, ok := err.(unix.Errno); ok {
+		switch errno {
+		case
+			unix.EACCES,
+			unix.EAGAIN,
+			unix.EBUSY,
+			unix.EINTR,
+			unix.ENOLCK,
+			unix.EDEADLK,
+			unix.ETIMEDOUT:
+			return _BUSY
+		case unix.EPERM:
+			return _PERM
+		}
+	}
+	return def
+}

sqlite3vfs/vfs_os_windows.go

@@ -0,0 +1,240 @@
+package sqlite3vfs
+
+import (
+	"io/fs"
+	"os"
+	"syscall"
+	"time"
+
+	"golang.org/x/sys/windows"
+)
+
+// osOpenFile is a simplified copy of [os.openFileNolog]
+// that uses syscall.FILE_SHARE_DELETE.
+// https://go.dev/src/os/file_windows.go
+//
+// See: https://go.dev/issue/32088
+func osOpenFile(name string, flag int, perm fs.FileMode) (*os.File, error) {
+	if name == "" {
+		return nil, &os.PathError{Op: "open", Path: name, Err: syscall.ENOENT}
+	}
+	r, e := syscallOpen(name, flag, uint32(perm.Perm()))
+	if e != nil {
+		return nil, &os.PathError{Op: "open", Path: name, Err: e}
+	}
+	return os.NewFile(uintptr(r), name), nil
+}
+
+func osAccess(path string, flags AccessFlag) error {
+	fi, err := os.Stat(path)
+	if err != nil {
+		return err
+	}
+	if flags == ACCESS_EXISTS {
+		return nil
+	}
+
+	var want fs.FileMode = windows.S_IRUSR
+	if flags == ACCESS_READWRITE {
+		want |= windows.S_IWUSR
+	}
+	if fi.IsDir() {
+		want |= windows.S_IXUSR
+	}
+	if fi.Mode()&want != want {
+		return fs.ErrPermission
+	}
+	return nil
+}
+
+func osGetSharedLock(file *os.File, timeout time.Duration) _ErrorCode {
+	// Acquire the PENDING lock temporarily before acquiring a new SHARED lock.
+	rc := osReadLock(file, _PENDING_BYTE, 1, timeout)
+
+	if rc == _OK {
+		// Acquire the SHARED lock.
+		rc = osReadLock(file, _SHARED_FIRST, _SHARED_SIZE, 0)
+
+		// Release the PENDING lock.
+		osUnlock(file, _PENDING_BYTE, 1)
+	}
+	return rc
+}
+
+func osGetExclusiveLock(file *os.File, timeout time.Duration) _ErrorCode {
+	if timeout == 0 {
+		timeout = time.Millisecond
+	}
+
+	// Release the SHARED lock.
+	osUnlock(file, _SHARED_FIRST, _SHARED_SIZE)
+
+	// Acquire the EXCLUSIVE lock.
+	rc := osWriteLock(file, _SHARED_FIRST, _SHARED_SIZE, timeout)
+
+	if rc != _OK {
+		// Reacquire the SHARED lock.
+		osReadLock(file, _SHARED_FIRST, _SHARED_SIZE, 0)
+	}
+	return rc
+}
+
+func osDowngradeLock(file *os.File, state LockLevel) _ErrorCode {
+	if state >= LOCK_EXCLUSIVE {
+		// Release the SHARED lock.
+		osUnlock(file, _SHARED_FIRST, _SHARED_SIZE)
+
+		// Reacquire the SHARED lock.
+		if rc := osReadLock(file, _SHARED_FIRST, _SHARED_SIZE, 0); rc != _OK {
+			// This should never happen.
+			// We should always be able to reacquire the read lock.
+			return _IOERR_RDLOCK
+		}
+	}
+
+	// Release the PENDING and RESERVED locks.
+	if state >= LOCK_RESERVED {
+		osUnlock(file, _RESERVED_BYTE, 1)
+	}
+	if state >= LOCK_PENDING {
+		osUnlock(file, _PENDING_BYTE, 1)
+	}
+	return _OK
+}
+
+func osReleaseLock(file *os.File, state LockLevel) _ErrorCode {
+	// Release all locks.
+	if state >= LOCK_RESERVED {
+		osUnlock(file, _RESERVED_BYTE, 1)
+	}
+	if state >= LOCK_SHARED {
+		osUnlock(file, _SHARED_FIRST, _SHARED_SIZE)
+	}
+	if state >= LOCK_PENDING {
+		osUnlock(file, _PENDING_BYTE, 1)
+	}
+	return _OK
+}
+
+func osUnlock(file *os.File, start, len uint32) _ErrorCode {
+	err := windows.UnlockFileEx(windows.Handle(file.Fd()),
+		0, len, 0, &windows.Overlapped{Offset: start})
+	if err == windows.ERROR_NOT_LOCKED {
+		return _OK
+	}
+	if err != nil {
+		return _IOERR_UNLOCK
+	}
+	return _OK
+}
+
+func osLock(file *os.File, flags, start, len uint32, timeout time.Duration, def _ErrorCode) _ErrorCode {
+	var err error
+	for {
+		err = windows.LockFileEx(windows.Handle(file.Fd()), flags,
+			0, len, 0, &windows.Overlapped{Offset: start})
+		if errno, _ := err.(windows.Errno); errno != windows.ERROR_LOCK_VIOLATION {
+			break
+		}
+		if timeout < time.Millisecond {
+			break
+		}
+		timeout -= time.Millisecond
+		time.Sleep(time.Millisecond)
+	}
+	return osLockErrorCode(err, def)
+}
+
+func osReadLock(file *os.File, start, len uint32, timeout time.Duration) _ErrorCode {
+	return osLock(file,
+		windows.LOCKFILE_FAIL_IMMEDIATELY,
+		start, len, timeout, _IOERR_RDLOCK)
+}
+
+func osWriteLock(file *os.File, start, len uint32, timeout time.Duration) _ErrorCode {
+	return osLock(file,
+		windows.LOCKFILE_FAIL_IMMEDIATELY|windows.LOCKFILE_EXCLUSIVE_LOCK,
+		start, len, timeout, _IOERR_LOCK)
+}
+
+func osCheckLock(file *os.File, start, len uint32) (bool, _ErrorCode) {
+	rc := osLock(file,
+		windows.LOCKFILE_FAIL_IMMEDIATELY,
+		start, len, 0, _IOERR_CHECKRESERVEDLOCK)
+	if rc == _BUSY {
+		return true, _OK
+	}
+	if rc == _OK {
+		osUnlock(file, start, len)
+	}
+	return false, rc
+}
+
+func osLockErrorCode(err error, def _ErrorCode) _ErrorCode {
+	if err == nil {
+		return _OK
+	}
+	if errno, ok := err.(windows.Errno); ok {
+		// https://devblogs.microsoft.com/oldnewthing/20140905-00/?p=63
+		switch errno {
+		case
+			windows.ERROR_LOCK_VIOLATION,
+			windows.ERROR_IO_PENDING,
+			windows.ERROR_OPERATION_ABORTED:
+			return _BUSY
+		}
+	}
+	return def
+}
+
+// syscallOpen is a simplified copy of [syscall.Open]
+// that uses syscall.FILE_SHARE_DELETE.
+// https://go.dev/src/syscall/syscall_windows.go
+func syscallOpen(path string, mode int, perm uint32) (fd syscall.Handle, err error) {
+	if len(path) == 0 {
+		return syscall.InvalidHandle, syscall.ERROR_FILE_NOT_FOUND
+	}
+	pathp, err := syscall.UTF16PtrFromString(path)
+	if err != nil {
+		return syscall.InvalidHandle, err
+	}
+	var access uint32
+	switch mode & (syscall.O_RDONLY | syscall.O_WRONLY | syscall.O_RDWR) {
+	case syscall.O_RDONLY:
+		access = syscall.GENERIC_READ
+	case syscall.O_WRONLY:
+		access = syscall.GENERIC_WRITE
+	case syscall.O_RDWR:
+		access = syscall.GENERIC_READ | syscall.GENERIC_WRITE
+	}
+	if mode&syscall.O_CREAT != 0 {
+		access |= syscall.GENERIC_WRITE
+	}
+	if mode&syscall.O_APPEND != 0 {
+		access &^= syscall.GENERIC_WRITE
+		access |= syscall.FILE_APPEND_DATA
+	}
+	sharemode := uint32(syscall.FILE_SHARE_READ | syscall.FILE_SHARE_WRITE | syscall.FILE_SHARE_DELETE)
+	var createmode uint32
+	switch {
+	case mode&(syscall.O_CREAT|syscall.O_EXCL) == (syscall.O_CREAT | syscall.O_EXCL):
+		createmode = syscall.CREATE_NEW
+	case mode&(syscall.O_CREAT|syscall.O_TRUNC) == (syscall.O_CREAT | syscall.O_TRUNC):
+		createmode = syscall.CREATE_ALWAYS
+	case mode&syscall.O_CREAT == syscall.O_CREAT:
+		createmode = syscall.OPEN_ALWAYS
+	case mode&syscall.O_TRUNC == syscall.O_TRUNC:
+		createmode = syscall.TRUNCATE_EXISTING
+	default:
+		createmode = syscall.OPEN_EXISTING
+	}
+	var attrs uint32 = syscall.FILE_ATTRIBUTE_NORMAL
+	if perm&syscall.S_IWRITE == 0 {
+		attrs = syscall.FILE_ATTRIBUTE_READONLY
+	}
+	if createmode == syscall.OPEN_EXISTING && access == syscall.GENERIC_READ {
+		// Necessary for opening directory handles.
+		attrs |= syscall.FILE_FLAG_BACKUP_SEMANTICS
+	}
+	return syscall.CreateFile(pathp, access, sharemode, nil, createmode, attrs, 0)
+}

sqlite3vfs/vfs_test.go

@@ -0,0 +1,344 @@
+package sqlite3vfs
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"io/fs"
+	"math"
+	"os"
+	"path/filepath"
+	"syscall"
+	"testing"
+	"time"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
+	"github.com/ncruces/julianday"
+)
+
+func Test_vfsLocaltime(t *testing.T) {
+	mod := util.NewMockModule(128)
+	ctx := context.TODO()
+
+	tm := time.Now()
+	rc := vfsLocaltime(ctx, mod, 4, tm.Unix())
+	if rc != 0 {
+		t.Fatal("returned", rc)
+	}
+
+	if s := util.ReadUint32(mod, 4+0*4); int(s) != tm.Second() {
+		t.Error("wrong second")
+	}
+	if m := util.ReadUint32(mod, 4+1*4); int(m) != tm.Minute() {
+		t.Error("wrong minute")
+	}
+	if h := util.ReadUint32(mod, 4+2*4); int(h) != tm.Hour() {
+		t.Error("wrong hour")
+	}
+	if d := util.ReadUint32(mod, 4+3*4); int(d) != tm.Day() {
+		t.Error("wrong day")
+	}
+	if m := util.ReadUint32(mod, 4+4*4); time.Month(1+m) != tm.Month() {
+		t.Error("wrong month")
+	}
+	if y := util.ReadUint32(mod, 4+5*4); 1900+int(y) != tm.Year() {
+		t.Error("wrong year")
+	}
+	if w := util.ReadUint32(mod, 4+6*4); time.Weekday(w) != tm.Weekday() {
+		t.Error("wrong weekday")
+	}
+	if d := util.ReadUint32(mod, 4+7*4); int(d) != tm.YearDay()-1 {
+		t.Error("wrong yearday")
+	}
+}
+
+func Test_vfsRandomness(t *testing.T) {
+	mod := util.NewMockModule(128)
+	ctx := context.TODO()
+
+	rc := vfsRandomness(ctx, mod, 0, 16, 4)
+	if rc != 16 {
+		t.Fatal("returned", rc)
+	}
+
+	var zero [16]byte
+	if got := util.View(mod, 4, 16); bytes.Equal(got, zero[:]) {
+		t.Fatal("all zero")
+	}
+}
+
+func Test_vfsSleep(t *testing.T) {
+	mod := util.NewMockModule(128)
+	ctx := context.TODO()
+
+	now := time.Now()
+	rc := vfsSleep(ctx, mod, 0, 123456)
+	if rc != 0 {
+		t.Fatal("returned", rc)
+	}
+
+	want := 123456 * time.Microsecond
+	if got := time.Since(now); got < want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+}
+
+func Test_vfsCurrentTime(t *testing.T) {
+	mod := util.NewMockModule(128)
+	ctx := context.TODO()
+
+	now := time.Now()
+	rc := vfsCurrentTime(ctx, mod, 0, 4)
+	if rc != 0 {
+		t.Fatal("returned", rc)
+	}
+
+	want := julianday.Float(now)
+	if got := util.ReadFloat64(mod, 4); float32(got) != float32(want) {
+		t.Errorf("got %v, want %v", got, want)
+	}
+}
+
+func Test_vfsCurrentTime64(t *testing.T) {
+	mod := util.NewMockModule(128)
+	ctx := context.TODO()
+
+	now := time.Now()
+	time.Sleep(time.Millisecond)
+	rc := vfsCurrentTime64(ctx, mod, 0, 4)
+	if rc != 0 {
+		t.Fatal("returned", rc)
+	}
+
+	day, nsec := julianday.Date(now)
+	want := day*86_400_000 + nsec/1_000_000
+	if got := util.ReadUint64(mod, 4); float32(got) != float32(want) {
+		t.Errorf("got %v, want %v", got, want)
+	}
+}
+
+func Test_vfsFullPathname(t *testing.T) {
+	mod := util.NewMockModule(128 + _MAX_PATHNAME)
+	util.WriteString(mod, 4, ".")
+	ctx := context.TODO()
+
+	rc := vfsFullPathname(ctx, mod, 0, 4, 0, 8)
+	if rc != _CANTOPEN_FULLPATH {
+		t.Errorf("returned %d, want %d", rc, _CANTOPEN_FULLPATH)
+	}
+
+	rc = vfsFullPathname(ctx, mod, 0, 4, _MAX_PATHNAME, 8)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+
+	want, _ := filepath.Abs(".")
+	if got := util.ReadString(mod, 8, _MAX_PATHNAME); got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+}
+
+func Test_vfsDelete(t *testing.T) {
+	name := filepath.Join(t.TempDir(), "test.db")
+
+	file, err := os.Create(name)
+	if err != nil {
+		t.Fatal(err)
+	}
+	file.Close()
+
+	mod := util.NewMockModule(128 + _MAX_PATHNAME)
+	util.WriteString(mod, 4, name)
+	ctx := context.TODO()
+
+	rc := vfsDelete(ctx, mod, 0, 4, 1)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+
+	if _, err := os.Stat(name); !errors.Is(err, fs.ErrNotExist) {
+		t.Fatal("did not delete the file")
+	}
+
+	rc = vfsDelete(ctx, mod, 0, 4, 1)
+	if rc != _IOERR_DELETE_NOENT {
+		t.Fatal("returned", rc)
+	}
+}
+
+func Test_vfsAccess(t *testing.T) {
+	dir := t.TempDir()
+	file := filepath.Join(t.TempDir(), "test.db")
+	if f, err := os.Create(file); err != nil {
+		t.Fatal(err)
+	} else {
+		f.Close()
+	}
+	if err := os.Chmod(file, syscall.S_IRUSR); err != nil {
+		t.Fatal(err)
+	}
+
+	mod := util.NewMockModule(128 + _MAX_PATHNAME)
+	util.WriteString(mod, 8, dir)
+	ctx := context.TODO()
+
+	rc := vfsAccess(ctx, mod, 0, 8, ACCESS_EXISTS, 4)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, 4); got != 1 {
+		t.Error("directory did not exist")
+	}
+
+	rc = vfsAccess(ctx, mod, 0, 8, ACCESS_READWRITE, 4)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, 4); got != 1 {
+		t.Error("can't access directory")
+	}
+
+	util.WriteString(mod, 8, file)
+	rc = vfsAccess(ctx, mod, 0, 8, ACCESS_READWRITE, 4)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, 4); got != 0 {
+		t.Error("can access file")
+	}
+}
+
+func Test_vfsFile(t *testing.T) {
+	mod := util.NewMockModule(128)
+	ctx, vfs := NewContext(context.TODO())
+	defer vfs.Close()
+
+	// Open a temporary file.
+	rc := vfsOpen(ctx, mod, 0, 0, 4, OPEN_CREATE|OPEN_EXCLUSIVE|OPEN_READWRITE|OPEN_DELETEONCLOSE, 0)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+
+	// Check sector size.
+	if size := vfsSectorSize(ctx, mod, 4); size != _DEFAULT_SECTOR_SIZE {
+		t.Fatal("returned", size)
+	}
+
+	// Write stuff.
+	text := "Hello world!"
+	util.WriteString(mod, 16, text)
+	rc = vfsWrite(ctx, mod, 4, 16, uint32(len(text)), 0)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+
+	// Check file size.
+	rc = vfsFileSize(ctx, mod, 4, 16)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, 16); got != uint32(len(text)) {
+		t.Errorf("got %d", got)
+	}
+
+	// Partial read at offset.
+	rc = vfsRead(ctx, mod, 4, 16, uint32(len(text)), 4)
+	if rc != _IOERR_SHORT_READ {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadString(mod, 16, 64); got != text[4:] {
+		t.Errorf("got %q", got)
+	}
+
+	// Truncate the file.
+	rc = vfsTruncate(ctx, mod, 4, 4)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+
+	// Check file size.
+	rc = vfsFileSize(ctx, mod, 4, 16)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, 16); got != 4 {
+		t.Errorf("got %d", got)
+	}
+
+	// Read at offset.
+	rc = vfsRead(ctx, mod, 4, 32, 4, 0)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadString(mod, 32, 64); got != text[:4] {
+		t.Errorf("got %q", got)
+	}
+
+	// Close the file.
+	rc = vfsClose(ctx, mod, 4)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+}
+
+func Test_vfsFile_psow(t *testing.T) {
+	mod := util.NewMockModule(128)
+	ctx, vfs := NewContext(context.TODO())
+	defer vfs.Close()
+
+	// Open a temporary file.
+	rc := vfsOpen(ctx, mod, 0, 0, 4, OPEN_CREATE|OPEN_EXCLUSIVE|OPEN_READWRITE|OPEN_DELETEONCLOSE, 0)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+
+	// Read powersafe overwrite.
+	util.WriteUint32(mod, 16, math.MaxUint32)
+	rc = vfsFileControl(ctx, mod, 4, _FCNTL_POWERSAFE_OVERWRITE, 16)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, 16); got == 0 {
+		t.Error("psow disabled")
+	}
+
+	// Unset powersafe overwrite.
+	util.WriteUint32(mod, 16, 0)
+	rc = vfsFileControl(ctx, mod, 4, _FCNTL_POWERSAFE_OVERWRITE, 16)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+
+	// Read powersafe overwrite.
+	util.WriteUint32(mod, 16, math.MaxUint32)
+	rc = vfsFileControl(ctx, mod, 4, _FCNTL_POWERSAFE_OVERWRITE, 16)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, 16); got != 0 {
+		t.Error("psow enabled")
+	}
+
+	// Set powersafe overwrite.
+	util.WriteUint32(mod, 16, 1)
+	rc = vfsFileControl(ctx, mod, 4, _FCNTL_POWERSAFE_OVERWRITE, 16)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+
+	// Read powersafe overwrite.
+	util.WriteUint32(mod, 16, math.MaxUint32)
+	rc = vfsFileControl(ctx, mod, 4, _FCNTL_POWERSAFE_OVERWRITE, 16)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := util.ReadUint32(mod, 16); got == 0 {
+		t.Error("psow disabled")
+	}
+
+	// Close the file.
+	rc = vfsClose(ctx, mod, 4)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+}

stmt.go

@@ -3,6 +3,8 @@ package sqlite3
 import (
 	"math"
 	"time"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
 )
 
 // Stmt is a prepared statement object.
@@ -10,8 +12,8 @@ import (
 // https://www.sqlite.org/c3ref/stmt.html
 type Stmt struct {
 	c      *Conn
-	handle uint32
 	err    error
+	handle uint32
 }
 
 // Close destroys the prepared statement object.
@@ -119,7 +121,7 @@ func (s *Stmt) BindName(param int) string {
 	if ptr == 0 {
 		return ""
 	}
-	return s.c.mem.readString(ptr, _MAX_STRING)
+	return util.ReadString(s.c.mod, ptr, _MAX_STRING)
 }
 
 // BindBool binds a bool to the prepared statement.
@@ -172,7 +174,7 @@ func (s *Stmt) BindText(param int, value string) error {
 	r := s.c.call(s.c.api.bindText,
 		uint64(s.handle), uint64(param),
 		uint64(ptr), uint64(len(value)),
-		s.c.api.destructor, _UTF8)
+		uint64(s.c.api.destructor), _UTF8)
 	return s.c.error(r[0])
 }
 
@@ -186,7 +188,7 @@ func (s *Stmt) BindBlob(param int, value []byte) error {
 	r := s.c.call(s.c.api.bindBlob,
 		uint64(s.handle), uint64(param),
 		uint64(ptr), uint64(len(value)),
-		s.c.api.destructor)
+		uint64(s.c.api.destructor))
 	return s.c.error(r[0])
 }
 
@@ -215,6 +217,9 @@ func (s *Stmt) BindNull(param int) error {
 //
 // https://www.sqlite.org/c3ref/bind_blob.html
 func (s *Stmt) BindTime(param int, value time.Time, format TimeFormat) error {
+	if format == TimeFormatDefault {
+		return s.bindRFC3339Nano(param, value)
+	}
 	switch v := format.Encode(value).(type) {
 	case string:
 		s.BindText(param, v)
@@ -223,11 +228,25 @@ func (s *Stmt) BindTime(param int, value time.Time, format TimeFormat) error {
 	case float64:
 		s.BindFloat(param, v)
 	default:
-		panic(assertErr())
+		panic(util.AssertErr())
 	}
 	return nil
 }
 
+func (s *Stmt) bindRFC3339Nano(param int, value time.Time) error {
+	const maxlen = uint64(len(time.RFC3339Nano))
+
+	ptr := s.c.new(maxlen)
+	buf := util.View(s.c.mod, ptr, maxlen)
+	buf = value.AppendFormat(buf[:0], time.RFC3339Nano)
+
+	r := s.c.call(s.c.api.bindText,
+		uint64(s.handle), uint64(param),
+		uint64(ptr), uint64(len(buf)),
+		uint64(s.c.api.destructor), _UTF8)
+	return s.c.error(r[0])
+}
+
 // ColumnCount returns the number of columns in a result set.
 //
 // https://www.sqlite.org/c3ref/column_count.html
@@ -247,9 +266,9 @@ func (s *Stmt) ColumnName(col int) string {
 
 	ptr := uint32(r[0])
 	if ptr == 0 {
-		panic(oomErr)
+		panic(util.OOMErr)
 	}
-	return s.c.mem.readString(ptr, _MAX_STRING)
+	return util.ReadString(s.c.mod, ptr, _MAX_STRING)
 }
 
 // ColumnType returns the initial [Datatype] of the result column.
@@ -320,7 +339,7 @@ func (s *Stmt) ColumnTime(col int, format TimeFormat) time.Time {
 	case NULL:
 		return time.Time{}
 	default:
-		panic(assertErr())
+		panic(util.AssertErr())
 	}
 	t, err := format.Decode(v)
 	if err != nil {
@@ -334,21 +353,7 @@ func (s *Stmt) ColumnTime(col int, format TimeFormat) time.Time {
 //
 // https://www.sqlite.org/c3ref/column_blob.html
 func (s *Stmt) ColumnText(col int) string {
-	r := s.c.call(s.c.api.columnText,
-		uint64(s.handle), uint64(col))
-
-	ptr := uint32(r[0])
-	if ptr == 0 {
-		r = s.c.call(s.c.api.errcode, uint64(s.handle))
-		s.err = s.c.error(r[0])
-		return ""
-	}
-
-	r = s.c.call(s.c.api.columnBytes,
-		uint64(s.handle), uint64(col))
-
-	mem := s.c.mem.view(ptr, r[0])
-	return string(mem)
+	return string(s.ColumnRawText(col))
 }
 
 // ColumnBlob appends to buf and returns
@@ -357,21 +362,53 @@ func (s *Stmt) ColumnText(col int) string {
 //
 // https://www.sqlite.org/c3ref/column_blob.html
 func (s *Stmt) ColumnBlob(col int, buf []byte) []byte {
-	r := s.c.call(s.c.api.columnBlob,
+	return append(buf, s.ColumnRawBlob(col)...)
+}
+
+// ColumnRawText returns the value of the result column as a []byte.
+// The []byte is owned by SQLite and may be invalidated by
+// subsequent calls to [Stmt] methods.
+// The leftmost column of the result set has the index 0.
+//
+// https://www.sqlite.org/c3ref/column_blob.html
+func (s *Stmt) ColumnRawText(col int) []byte {
+	r := s.c.call(s.c.api.columnText,
 		uint64(s.handle), uint64(col))
 
 	ptr := uint32(r[0])
 	if ptr == 0 {
-		r = s.c.call(s.c.api.errcode, uint64(s.handle))
+		r = s.c.call(s.c.api.errcode, uint64(s.c.handle))
 		s.err = s.c.error(r[0])
-		return buf[0:0]
+		return nil
 	}
 
 	r = s.c.call(s.c.api.columnBytes,
 		uint64(s.handle), uint64(col))
 
-	mem := s.c.mem.view(ptr, r[0])
-	return append(buf[0:0], mem...)
+	return util.View(s.c.mod, ptr, r[0])
+}
+
+// ColumnRawBlob returns the value of the result column as a []byte.
+// The []byte is owned by SQLite and may be invalidated by
+// subsequent calls to [Stmt] methods.
+// The leftmost column of the result set has the index 0.
+//
+// https://www.sqlite.org/c3ref/column_blob.html
+func (s *Stmt) ColumnRawBlob(col int) []byte {
+	r := s.c.call(s.c.api.columnBlob,
+		uint64(s.handle), uint64(col))
+
+	ptr := uint32(r[0])
+	if ptr == 0 {
+		r = s.c.call(s.c.api.errcode, uint64(s.c.handle))
+		s.err = s.c.error(r[0])
+		return nil
+	}
+
+	r = s.c.call(s.c.api.columnBytes,
+		uint64(s.handle), uint64(col))
+
+	return util.View(s.c.mod, ptr, r[0])
 }
 
 // Return true if stmt is an empty SQL statement.

tests/backup_test.go

@@ -0,0 +1,127 @@
+package tests
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+	_ "github.com/ncruces/go-sqlite3/embed"
+)
+
+func TestBackup(t *testing.T) {
+	t.Parallel()
+
+	backupName := filepath.Join(t.TempDir(), "backup.db")
+
+	func() { // Create backup.
+		db, err := sqlite3.Open(":memory:")
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer db.Close()
+
+		err = db.Exec(`CREATE TABLE IF NOT EXISTS users (id INT, name VARCHAR(10))`)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		err = db.Exec(`INSERT INTO users (id, name) VALUES (0, 'go'), (1, 'zig'), (2, 'whatever')`)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		err = db.Backup("main", backupName)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		err = db.Close()
+		if err != nil {
+			t.Fatal(err)
+		}
+	}()
+
+	func() { // Restore backup.
+		db, err := sqlite3.Open(":memory:")
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer db.Close()
+
+		err = db.Restore("main", backupName)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		stmt, _, err := db.Prepare(`SELECT id, name FROM users`)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer stmt.Close()
+
+		row := 0
+		ids := []int{0, 1, 2}
+		names := []string{"go", "zig", "whatever"}
+		for ; stmt.Step(); row++ {
+			id := stmt.ColumnInt(0)
+			name := stmt.ColumnText(1)
+
+			if id != ids[row] {
+				t.Errorf("got %d, want %d", id, ids[row])
+			}
+			if name != names[row] {
+				t.Errorf("got %q, want %q", name, names[row])
+			}
+		}
+		if row != 3 {
+			t.Errorf("got %d, want %d", row, len(ids))
+		}
+
+		if err := stmt.Err(); err != nil {
+			t.Fatal(err)
+		}
+
+		err = stmt.Close()
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		err = db.Close()
+		if err != nil {
+			t.Fatal(err)
+		}
+	}()
+
+	func() { // Errors.
+		db, err := sqlite3.Open(backupName)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer db.Close()
+
+		tx, err := db.BeginExclusive()
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		err = db.Restore("main", backupName)
+		if err == nil {
+			t.Fatal("want error")
+		}
+
+		err = tx.Rollback()
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		err = db.Restore("main", backupName)
+		if err == nil {
+			t.Fatal("want error")
+		}
+
+		err = db.Close()
+		if err != nil {
+			t.Fatal(err)
+		}
+	}()
+}

tests/blob_test.go

@@ -5,6 +5,7 @@ import (
 	"crypto/rand"
 	"errors"
 	"fmt"
+	"hash/adler32"
 	"io"
 	"testing"
 
@@ -48,17 +49,17 @@ func TestBlob(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	_, err = io.Copy(blob, bytes.NewReader(data[:size/2]))
+	_, err = blob.Write(data[:size/2])
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	_, err = io.Copy(blob, bytes.NewReader(data[:]))
-	if !errors.Is(err, sqlite3.ERROR) {
-		t.Fatal("want error")
+	n, err := blob.Write(data[:])
+	if n != 0 || !errors.Is(err, sqlite3.ERROR) {
+		t.Fatalf("got (%d, %v), want (0, ERROR)", n, err)
 	}
 
-	_, err = io.Copy(blob, bytes.NewReader(data[size/2:size]))
+	_, err = blob.Write(data[size/2 : size])
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -87,6 +88,126 @@ func TestBlob(t *testing.T) {
 	}
 }
 
+func TestBlob_large(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`CREATE TABLE IF NOT EXISTS test (col)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Exec(`INSERT INTO test VALUES (zeroblob(1000000))`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	blob, err := db.OpenBlob("main", "test", "col", db.LastInsertRowID(), true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer blob.Close()
+
+	size := blob.Size()
+	if size != 1000000 {
+		t.Errorf("got %d, want 1000000", size)
+	}
+
+	hash := adler32.New()
+	_, err = io.CopyN(blob, io.TeeReader(rand.Reader, hash), 1000000)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = blob.Seek(0, io.SeekStart)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	want := hash.Sum32()
+	hash.Reset()
+	_, err = io.Copy(hash, blob)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if got := hash.Sum32(); got != want {
+		t.Fatalf("got %d, want %d", got, want)
+	}
+
+	if err := blob.Close(); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := db.Close(); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestBlob_overflow(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`CREATE TABLE IF NOT EXISTS test (col)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Exec(`INSERT INTO test VALUES (zeroblob(1024))`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	blob, err := db.OpenBlob("main", "test", "col", db.LastInsertRowID(), true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer blob.Close()
+
+	n, err := blob.ReadFrom(rand.Reader)
+	if n != 1024 || !errors.Is(err, sqlite3.ERROR) {
+		t.Fatalf("got (%d, %v), want (0, ERROR)", n, err)
+	}
+
+	n, err = blob.ReadFrom(rand.Reader)
+	if n != 0 || !errors.Is(err, sqlite3.ERROR) {
+		t.Fatalf("got (%d, %v), want (0, ERROR)", n, err)
+	}
+
+	_, err = blob.Seek(-128, io.SeekEnd)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	n, err = blob.WriteTo(io.Discard)
+	if n != 128 || err != nil {
+		t.Fatalf("got (%d, %v), want (128, nil)", n, err)
+	}
+
+	n, err = blob.WriteTo(io.Discard)
+	if n != 0 || err != nil {
+		t.Fatalf("got (%d, %v), want (0, nil)", n, err)
+	}
+
+	if err := blob.Close(); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := db.Close(); err != nil {
+		t.Fatal(err)
+	}
+}
+
 func TestBlob_invalid(t *testing.T) {
 	t.Parallel()
 

tests/bradfitz/sql_test.go

@@ -126,7 +126,7 @@ func testTxQuery(t params) {
 		if r.Err() != nil {
 			t.Fatal(err)
 		}
-		t.Fatal("expected one rows")
+		t.Fatal("expected one row")
 	}
 
 	var name string

tests/conn_test.go

@@ -3,6 +3,7 @@ package tests
 import (
 	"context"
 	"errors"
+	"reflect"
 	"strings"
 	"testing"
 
@@ -13,7 +14,7 @@ import (
 func TestConn_Open_dir(t *testing.T) {
 	t.Parallel()
 
-	_, err := sqlite3.Open(".")
+	_, err := sqlite3.OpenFlags(".", 0)
 	if err == nil {
 		t.Fatal("want error")
 	}
@@ -58,6 +59,41 @@ func TestConn_Close_BUSY(t *testing.T) {
 	}
 }
 
+func TestConn_Pragma(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open("file::memory:?_pragma=busy_timeout(1000)")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	got, err := db.Pragma("busy_timeout")
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := []string{"1000"}
+
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("got %v, want %v", got, want)
+	}
+
+	var serr *sqlite3.Error
+	_, err = db.Pragma("+")
+	if err == nil {
+		t.Error("want: error")
+	}
+	if !errors.As(err, &serr) {
+		t.Fatalf("got %T, want sqlite3.Error", err)
+	}
+	if rc := serr.Code(); rc != sqlite3.ERROR {
+		t.Errorf("got %d, want sqlite3.ERROR", rc)
+	}
+	if got := err.Error(); got != `sqlite3: SQL logic error: near "+": syntax error` {
+		t.Error("got message:", got)
+	}
+}
+
 func TestConn_SetInterrupt(t *testing.T) {
 	t.Parallel()
 
@@ -202,59 +238,3 @@ func TestConn_Prepare_invalid(t *testing.T) {
 		t.Error("got message:", got)
 	}
 }
-
-func TestConn_MustPrepare_empty(t *testing.T) {
-	t.Parallel()
-
-	db, err := sqlite3.Open(":memory:")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer db.Close()
-
-	defer func() { _ = recover() }()
-	_ = db.MustPrepare(``)
-	t.Error("want panic")
-}
-
-func TestConn_MustPrepare_tail(t *testing.T) {
-	t.Parallel()
-
-	db, err := sqlite3.Open(":memory:")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer db.Close()
-
-	defer func() { _ = recover() }()
-	_ = db.MustPrepare(`SELECT 1; -- HERE`)
-	t.Error("want panic")
-}
-
-func TestConn_MustPrepare_invalid(t *testing.T) {
-	t.Parallel()
-
-	db, err := sqlite3.Open(":memory:")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer db.Close()
-
-	defer func() { _ = recover() }()
-	_ = db.MustPrepare(`SELECT`)
-	t.Error("want panic")
-}
-
-func TestConn_Pragma(t *testing.T) {
-	t.Parallel()
-
-	db, err := sqlite3.Open(":memory:")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer db.Close()
-
-	defer func() { _ = recover() }()
-	_ = db.Pragma("encoding=''")
-	t.Error("want panic")
-}

tests/ext_test.go

@@ -0,0 +1,77 @@
+package tests
+
+import (
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+)
+
+func Test_base64(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	// base64
+	stmt, _, err := db.Prepare(`SELECT base64('TWFueSBoYW5kcyBtYWtlIGxpZ2h0IHdvcmsu')`)
+	if err != nil {
+		t.Error(err)
+	}
+	defer stmt.Close()
+
+	if !stmt.Step() {
+		t.Fatal("expected one row")
+	}
+	if got := stmt.ColumnText(0); got != "Many hands make light work." {
+		t.Errorf("got %q", got)
+	}
+}
+
+func Test_decimal(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	stmt, _, err := db.Prepare(`SELECT decimal_add(decimal('0.1'), decimal('0.2')) = decimal('0.3')`)
+	if err != nil {
+		t.Error(err)
+	}
+	defer stmt.Close()
+
+	if !stmt.Step() {
+		t.Fatal("expected one row")
+	}
+	if !stmt.ColumnBool(0) {
+		t.Error("want true")
+	}
+}
+
+func Test_uint(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	stmt, _, err := db.Prepare(`SELECT 'z2' < 'z11' COLLATE UINT`)
+	if err != nil {
+		t.Error(err)
+	}
+	defer stmt.Close()
+
+	if !stmt.Step() {
+		t.Fatal("expected one row")
+	}
+	if !stmt.ColumnBool(0) {
+		t.Error("want true")
+	}
+}

tests/parallel/parallel_test.go

@@ -14,8 +14,15 @@ import (
 )
 
 func TestParallel(t *testing.T) {
+	var iter int
+	if testing.Short() {
+		iter = 1000
+	} else {
+		iter = 5000
+	}
+
 	name := filepath.Join(t.TempDir(), "test.db")
-	testParallel(t, name, 1000)
+	testParallel(t, name, iter)
 	testIntegrity(t, name)
 }
 
@@ -135,7 +142,7 @@ func testParallel(t *testing.T, name string, n int) {
 	}
 
 	var group errgroup.Group
-	group.SetLimit(4)
+	group.SetLimit(6)
 	for i := 0; i < n; i++ {
 		if i&7 != 7 {
 			group.Go(reader)

tests/time_test.go

@@ -0,0 +1,169 @@
+package tests
+
+import (
+	"reflect"
+	"testing"
+	"time"
+
+	"github.com/ncruces/go-sqlite3"
+)
+
+func TestTimeFormat_Encode(t *testing.T) {
+	t.Parallel()
+
+	reference := time.Date(2013, 10, 7, 4, 23, 19, 120_000_000, time.FixedZone("", -4*3600))
+
+	tests := []struct {
+		fmt  sqlite3.TimeFormat
+		time time.Time
+		want any
+	}{
+		{sqlite3.TimeFormatDefault, reference, "2013-10-07T04:23:19.12-04:00"},
+		{sqlite3.TimeFormatJulianDay, reference, 2456572.849526851851852},
+		{sqlite3.TimeFormatUnix, reference, int64(1381134199)},
+		{sqlite3.TimeFormatUnixFrac, reference, 1381134199.120},
+		{sqlite3.TimeFormatUnixMilli, reference, int64(1381134199_120)},
+		{sqlite3.TimeFormatUnixMicro, reference, int64(1381134199_120000)},
+		{sqlite3.TimeFormatUnixNano, reference, int64(1381134199_120000000)},
+		{sqlite3.TimeFormat7, reference, "2013-10-07T08:23:19.120"},
+	}
+	for _, tt := range tests {
+		t.Run("", func(t *testing.T) {
+			if got := tt.fmt.Encode(tt.time); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("%q.Encode(%v) = %v, want %v", tt.fmt, tt.time, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestTimeFormat_Decode(t *testing.T) {
+	t.Parallel()
+
+	reference := time.Date(2013, 10, 7, 4, 23, 19, 120_000_000, time.FixedZone("", -4*3600))
+	refnodate := time.Date(2000, 01, 1, 4, 23, 19, 120_000_000, time.FixedZone("", -4*3600))
+
+	tests := []struct {
+		fmt       sqlite3.TimeFormat
+		val       any
+		want      time.Time
+		wantDelta time.Duration
+		wantErr   bool
+	}{
+		{sqlite3.TimeFormatJulianDay, "2456572.849526851851852", reference, 0, false},
+		{sqlite3.TimeFormatJulianDay, 2456572.849526851851852, reference, time.Millisecond, false},
+		{sqlite3.TimeFormatJulianDay, int64(2456572), reference, 24 * time.Hour, false},
+		{sqlite3.TimeFormatJulianDay, false, time.Time{}, 0, true},
+
+		{sqlite3.TimeFormatUnix, "1381134199.120", reference, time.Microsecond, false},
+		{sqlite3.TimeFormatUnix, 1381134199.120, reference, time.Microsecond, false},
+		{sqlite3.TimeFormatUnix, int64(1381134199), reference, time.Second, false},
+		{sqlite3.TimeFormatUnix, "abc", time.Time{}, 0, true},
+		{sqlite3.TimeFormatUnix, false, time.Time{}, 0, true},
+
+		{sqlite3.TimeFormatUnixMilli, "1381134199120", reference, 0, false},
+		{sqlite3.TimeFormatUnixMilli, 1381134199.120e3, reference, 0, false},
+		{sqlite3.TimeFormatUnixMilli, int64(1381134199_120), reference, 0, false},
+		{sqlite3.TimeFormatUnixMilli, "abc", time.Time{}, 0, true},
+		{sqlite3.TimeFormatUnixMilli, false, time.Time{}, 0, true},
+
+		{sqlite3.TimeFormatUnixMicro, "1381134199120000", reference, 0, false},
+		{sqlite3.TimeFormatUnixMicro, 1381134199.120e6, reference, 0, false},
+		{sqlite3.TimeFormatUnixMicro, int64(1381134199_120000), reference, 0, false},
+		{sqlite3.TimeFormatUnixMicro, "abc", time.Time{}, 0, true},
+		{sqlite3.TimeFormatUnixMicro, false, time.Time{}, 0, true},
+
+		{sqlite3.TimeFormatUnixNano, "1381134199120000000", reference, 0, false},
+		{sqlite3.TimeFormatUnixNano, 1381134199.120e9, reference, 0, false},
+		{sqlite3.TimeFormatUnixNano, int64(1381134199_120000000), reference, 0, false},
+		{sqlite3.TimeFormatUnixNano, "abc", time.Time{}, 0, true},
+		{sqlite3.TimeFormatUnixNano, false, time.Time{}, 0, true},
+
+		{sqlite3.TimeFormatAuto, "2456572.849526851851852", reference, time.Millisecond, false},
+		{sqlite3.TimeFormatAuto, "2456572", reference, 24 * time.Hour, false},
+		{sqlite3.TimeFormatAuto, "1381134199.120", reference, time.Microsecond, false},
+		{sqlite3.TimeFormatAuto, "1381134199.120e3", reference, time.Microsecond, false},
+		{sqlite3.TimeFormatAuto, "1381134199.120e6", reference, time.Microsecond, false},
+		{sqlite3.TimeFormatAuto, "1381134199.120e9", reference, time.Microsecond, false},
+		{sqlite3.TimeFormatAuto, "1381134199", reference, time.Second, false},
+		{sqlite3.TimeFormatAuto, "1381134199120", reference, 0, false},
+		{sqlite3.TimeFormatAuto, "1381134199120000", reference, 0, false},
+		{sqlite3.TimeFormatAuto, "1381134199120000000", reference, 0, false},
+		{sqlite3.TimeFormatAuto, "2013-10-07 04:23:19.12-04:00", reference, 0, false},
+		{sqlite3.TimeFormatAuto, "04:23:19.12-04:00", refnodate, 0, false},
+		{sqlite3.TimeFormatAuto, "abc", time.Time{}, 0, true},
+		{sqlite3.TimeFormatAuto, false, time.Time{}, 0, true},
+
+		{sqlite3.TimeFormat3, "2013-10-07 04:23:19.12-04:00", reference, 0, false},
+		{sqlite3.TimeFormat3, "2013-10-07 08:23:19.12", reference, 0, false},
+		{sqlite3.TimeFormat9, "04:23:19.12-04:00", refnodate, 0, false},
+		{sqlite3.TimeFormat9, "08:23:19.12", refnodate, 0, false},
+		{sqlite3.TimeFormat3, false, time.Time{}, 0, true},
+		{sqlite3.TimeFormat9, false, time.Time{}, 0, true},
+
+		{sqlite3.TimeFormatDefault, "2013-10-07T04:23:19.12-04:00", reference, 0, false},
+		{sqlite3.TimeFormatDefault, "2013-10-07T08:23:19.12Z", reference, 0, false},
+		{sqlite3.TimeFormatDefault, false, time.Time{}, 0, true},
+	}
+
+	for _, tt := range tests {
+		t.Run("", func(t *testing.T) {
+			got, err := tt.fmt.Decode(tt.val)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("%q.Decode(%v) error = %v, wantErr %v", tt.fmt, tt.val, err, tt.wantErr)
+				return
+			}
+			if tt.want.Sub(got).Abs() > tt.wantDelta {
+				t.Errorf("%q.Decode(%v) = %v, want %v", tt.fmt, tt.val, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestDB_timeCollation(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`CREATE TABLE IF NOT EXISTS times (tstamp COLLATE TIME)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	stmt, _, err := db.Prepare(`INSERT INTO times VALUES (?), (?), (?)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stmt.Close()
+
+	stmt.BindTime(1, time.Unix(0, 0).UTC(), sqlite3.TimeFormatDefault)
+	stmt.BindTime(2, time.Unix(0, -1).UTC(), sqlite3.TimeFormatDefault)
+	stmt.BindTime(3, time.Unix(0, +1).UTC(), sqlite3.TimeFormatDefault)
+	stmt.Step()
+
+	err = stmt.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	stmt, _, err = db.Prepare(`SELECT tstamp FROM times ORDER BY tstamp`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var t0 time.Time
+	for stmt.Step() {
+		t1 := stmt.ColumnTime(0, sqlite3.TimeFormatAuto)
+		if t0.After(t1) {
+			t.Errorf("got %v after %v", t0, t1)
+		}
+		t0 = t1
+	}
+	err = stmt.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+}

tests/tx_test.go

@@ -29,6 +29,7 @@ func TestConn_Transaction_exec(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
+		defer stmt.Close()
 		if stmt.Step() {
 			return stmt.ColumnInt(0)
 		}
@@ -117,6 +118,7 @@ func TestConn_Transaction_panic(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
+		defer stmt.Close()
 		if stmt.Step() {
 			got := stmt.ColumnInt(0)
 			if got != 1 {
@@ -183,10 +185,10 @@ func TestConn_Transaction_interrupt(t *testing.T) {
 		t.Errorf("got %v, want sqlite3.INTERRUPT", err)
 	}
 
-	var nilErr error
-	tx.End(&nilErr)
-	if !errors.Is(nilErr, sqlite3.INTERRUPT) {
-		t.Errorf("got %v, want sqlite3.INTERRUPT", nilErr)
+	err = nil
+	tx.End(&err)
+	if !errors.Is(err, sqlite3.INTERRUPT) {
+		t.Errorf("got %v, want sqlite3.INTERRUPT", err)
 	}
 
 	db.SetInterrupt(context.Background())
@@ -208,6 +210,33 @@ func TestConn_Transaction_interrupt(t *testing.T) {
 	}
 }
 
+func TestConn_Transaction_interrupted(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	db.SetInterrupt(ctx)
+	cancel()
+
+	tx := db.Begin()
+
+	err = tx.Commit()
+	if !errors.Is(err, sqlite3.INTERRUPT) {
+		t.Errorf("got %v, want sqlite3.INTERRUPT", err)
+	}
+
+	err = nil
+	tx.End(&err)
+	if !errors.Is(err, sqlite3.INTERRUPT) {
+		t.Errorf("got %v, want sqlite3.INTERRUPT", err)
+	}
+}
+
 func TestConn_Transaction_rollback(t *testing.T) {
 	t.Parallel()
 
@@ -275,6 +304,7 @@ func TestConn_Savepoint_exec(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
+		defer stmt.Close()
 		if stmt.Step() {
 			return stmt.ColumnInt(0)
 		}
@@ -283,7 +313,7 @@ func TestConn_Savepoint_exec(t *testing.T) {
 	}
 
 	insert := func(succeed bool) (err error) {
-		defer db.Savepoint()(&err)
+		defer db.Savepoint().Release(&err)
 
 		err = db.Exec(`INSERT INTO test VALUES ('hello')`)
 		if err != nil {
@@ -341,7 +371,7 @@ func TestConn_Savepoint_panic(t *testing.T) {
 	}
 
 	panics := func() (err error) {
-		defer db.Savepoint()(&err)
+		defer db.Savepoint().Release(&err)
 
 		err = db.Exec(`INSERT INTO test VALUES ('hello')`)
 		if err != nil {
@@ -361,6 +391,7 @@ func TestConn_Savepoint_panic(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
+		defer stmt.Close()
 		if stmt.Step() {
 			got := stmt.ColumnInt(0)
 			if got != 1 {
@@ -391,12 +422,12 @@ func TestConn_Savepoint_interrupt(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	release := db.Savepoint()
+	savept := db.Savepoint()
 	err = db.Exec(`INSERT INTO test VALUES (1)`)
 	if err != nil {
 		t.Fatal(err)
 	}
-	release(&err)
+	savept.Release(&err)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -404,19 +435,19 @@ func TestConn_Savepoint_interrupt(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	db.SetInterrupt(ctx)
 
-	release1 := db.Savepoint()
+	savept1 := db.Savepoint()
 	err = db.Exec(`INSERT INTO test VALUES (2)`)
 	if err != nil {
 		t.Fatal(err)
 	}
-	release2 := db.Savepoint()
+	savept2 := db.Savepoint()
 	err = db.Exec(`INSERT INTO test VALUES (3)`)
 	if err != nil {
 		t.Fatal(err)
 	}
 
 	cancel()
-	db.Savepoint()(&err)
+	db.Savepoint().Release(&err)
 	if !errors.Is(err, sqlite3.INTERRUPT) {
 		t.Errorf("got %v, want sqlite3.INTERRUPT", err)
 	}
@@ -427,15 +458,15 @@ func TestConn_Savepoint_interrupt(t *testing.T) {
 	}
 
 	err = context.Canceled
-	release2(&err)
+	savept2.Release(&err)
 	if err != context.Canceled {
 		t.Fatal(err)
 	}
 
-	var nilErr error
-	release1(&nilErr)
-	if !errors.Is(nilErr, sqlite3.INTERRUPT) {
-		t.Errorf("got %v, want sqlite3.INTERRUPT", nilErr)
+	err = nil
+	savept1.Release(&err)
+	if !errors.Is(err, sqlite3.INTERRUPT) {
+		t.Errorf("got %v, want sqlite3.INTERRUPT", err)
 	}
 
 	db.SetInterrupt(context.Background())
@@ -471,7 +502,7 @@ func TestConn_Savepoint_rollback(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	release := db.Savepoint()
+	savept := db.Savepoint()
 	err = db.Exec(`INSERT INTO test VALUES (1)`)
 	if err != nil {
 		t.Fatal(err)
@@ -480,7 +511,7 @@ func TestConn_Savepoint_rollback(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	release(&err)
+	savept.Release(&err)
 	if err != nil {
 		t.Fatal(err)
 	}

tests/type_test.go

@@ -1,19 +1,23 @@
-package sqlite3
+package tests
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+)
 
 func TestDatatype_String(t *testing.T) {
 	t.Parallel()
 
 	tests := []struct {
-		data Datatype
+		data sqlite3.Datatype
 		want string
 	}{
-		{INTEGER, "INTEGER"},
-		{FLOAT, "FLOAT"},
-		{TEXT, "TEXT"},
-		{BLOB, "BLOB"},
-		{NULL, "NULL"},
+		{sqlite3.INTEGER, "INTEGER"},
+		{sqlite3.FLOAT, "FLOAT"},
+		{sqlite3.TEXT, "TEXT"},
+		{sqlite3.BLOB, "BLOB"},
+		{sqlite3.NULL, "NULL"},
 		{10, "10"},
 	}
 	for _, tt := range tests {

time.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/ncruces/go-sqlite3/internal/util"
 	"github.com/ncruces/julianday"
 )
 
@@ -62,13 +63,18 @@ const (
 // [TimeFormatDefault] and [TimeFormatAuto] encode using [time.RFC3339Nano],
 // with nanosecond accuracy, and preserving any timezone offset.
 //
-// This is the format used by the database/sql driver:
-// [database/sql.Row.Scan] is able to decode as [time.Time]
+// This is the format used by the [database/sql] driver:
+// [database/sql.Row.Scan] will decode as [time.Time]
 // values encoded with [time.RFC3339Nano].
 //
 // Time values encoded with [time.RFC3339Nano] cannot be sorted as strings
 // to produce a time-ordered sequence.
-// Use [TimeFormat7] for time-ordered encoding.
+//
+// Assuming that the time zones of the time values are the same (e.g., all in UTC),
+// and expressed using the same string (e.g., all "Z" or all "+00:00"),
+// use the TIME [collating sequence] to produce a time-ordered sequence.
+//
+// Otherwise, use [TimeFormat7] for time-ordered encoding.
 //
 // Formats [TimeFormat1] through [TimeFormat10]
 // convert time values to UTC before encoding.
@@ -78,6 +84,8 @@ const (
 // or an int64 for the other numeric formats.
 //
 // https://www.sqlite.org/lang_datefunc.html
+//
+// [collating sequence]: https://www.sqlite.org/datatype3.html#collating_sequences
 func (f TimeFormat) Encode(t time.Time) any {
 	switch f {
 	// Numeric formats
@@ -123,9 +131,9 @@ func (f TimeFormat) Encode(t time.Time) any {
 // [TimeFormatAuto] implements (and extends) the SQLite auto modifier.
 // Julian day numbers are safe to use for historical dates,
 // from 4712BC through 9999AD.
-// Unix timestamps (expressed in seconds, milliseconds, microseconds, or nanoseconds),
-// are safe to use for current events, from 1980 through at least 2260.
-// Unix timestamps before 1980 may be misinterpreted as julian day numbers,
+// Unix timestamps (expressed in seconds, milliseconds, microseconds, or nanoseconds)
+// are safe to use for current events, from at least 1980 through at least 2260.
+// Unix timestamps before 1980 and after 9999 may be misinterpreted as julian day numbers,
 // or have the wrong time unit.
 //
 // https://www.sqlite.org/lang_datefunc.html
@@ -141,7 +149,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		case int64:
 			return julianday.Time(v, 0), nil
 		default:
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 
 	case TimeFormatUnix, TimeFormatUnixFrac:
@@ -160,7 +168,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		case int64:
 			return time.Unix(v, 0), nil
 		default:
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 
 	case TimeFormatUnixMilli:
@@ -177,7 +185,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		case int64:
 			return time.UnixMilli(int64(v)), nil
 		default:
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 
 	case TimeFormatUnixMicro:
@@ -194,14 +202,14 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		case int64:
 			return time.UnixMicro(int64(v)), nil
 		default:
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 
 	case TimeFormatUnixNano:
 		if s, ok := v.(string); ok {
 			i, err := strconv.ParseInt(s, 10, 64)
 			if err != nil {
-				return time.Time{}, timeErr
+				return time.Time{}, util.TimeErr
 			}
 			v = i
 		}
@@ -211,7 +219,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		case int64:
 			return time.Unix(0, int64(v)), nil
 		default:
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 
 	// Special formats
@@ -281,7 +289,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 			}
 			return TimeFormatUnixNano.Decode(v)
 		default:
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 
 	case
@@ -293,7 +301,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		TimeFormat7, TimeFormat7TZ:
 		s, ok := v.(string)
 		if !ok {
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 		return f.parseRelaxed(s)
 
@@ -303,7 +311,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		TimeFormat10, TimeFormat10TZ:
 		s, ok := v.(string)
 		if !ok {
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 		t, err := f.parseRelaxed(s)
 		return t.AddDate(2000, 0, 0), err
@@ -311,7 +319,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 	default:
 		s, ok := v.(string)
 		if !ok {
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 		if f == "" {
 			f = time.RFC3339Nano

time_test.go

@@ -1,118 +0,0 @@
-package sqlite3
-
-import (
-	"reflect"
-	"testing"
-	"time"
-)
-
-func TestTimeFormat_Encode(t *testing.T) {
-	t.Parallel()
-
-	reference := time.Date(2013, 10, 7, 4, 23, 19, 120_000_000, time.FixedZone("", -4*3600))
-
-	tests := []struct {
-		fmt  TimeFormat
-		time time.Time
-		want any
-	}{
-		{TimeFormatDefault, reference, "2013-10-07T04:23:19.12-04:00"},
-		{TimeFormatJulianDay, reference, 2456572.849526851851852},
-		{TimeFormatUnix, reference, int64(1381134199)},
-		{TimeFormatUnixFrac, reference, 1381134199.120},
-		{TimeFormatUnixMilli, reference, int64(1381134199_120)},
-		{TimeFormatUnixMicro, reference, int64(1381134199_120000)},
-		{TimeFormatUnixNano, reference, int64(1381134199_120000000)},
-		{TimeFormat7, reference, "2013-10-07T08:23:19.120"},
-	}
-	for _, tt := range tests {
-		t.Run("", func(t *testing.T) {
-			if got := tt.fmt.Encode(tt.time); !reflect.DeepEqual(got, tt.want) {
-				t.Errorf("%q.Encode(%v) = %v, want %v", tt.fmt, tt.time, got, tt.want)
-			}
-		})
-	}
-}
-
-func TestTimeFormat_Decode(t *testing.T) {
-	t.Parallel()
-
-	reference := time.Date(2013, 10, 7, 4, 23, 19, 120_000_000, time.FixedZone("", -4*3600))
-	reftime := time.Date(2000, 1, 1, 4, 23, 19, 120_000_000, time.FixedZone("", -4*3600))
-
-	tests := []struct {
-		fmt       TimeFormat
-		val       any
-		want      time.Time
-		wantDelta time.Duration
-		wantErr   bool
-	}{
-		{TimeFormatJulianDay, "2456572.849526851851852", reference, 0, false},
-		{TimeFormatJulianDay, 2456572.849526851851852, reference, time.Millisecond, false},
-		{TimeFormatJulianDay, int64(2456572), reference, 24 * time.Hour, false},
-		{TimeFormatJulianDay, false, time.Time{}, 0, true},
-
-		{TimeFormatUnix, "1381134199.120", reference, time.Microsecond, false},
-		{TimeFormatUnix, 1381134199.120, reference, time.Microsecond, false},
-		{TimeFormatUnix, int64(1381134199), reference, time.Second, false},
-		{TimeFormatUnix, "abc", time.Time{}, 0, true},
-		{TimeFormatUnix, false, time.Time{}, 0, true},
-
-		{TimeFormatUnixMilli, "1381134199120", reference, 0, false},
-		{TimeFormatUnixMilli, 1381134199.120e3, reference, 0, false},
-		{TimeFormatUnixMilli, int64(1381134199_120), reference, 0, false},
-		{TimeFormatUnixMilli, "abc", time.Time{}, 0, true},
-		{TimeFormatUnixMilli, false, time.Time{}, 0, true},
-
-		{TimeFormatUnixMicro, "1381134199120000", reference, 0, false},
-		{TimeFormatUnixMicro, 1381134199.120e6, reference, 0, false},
-		{TimeFormatUnixMicro, int64(1381134199_120000), reference, 0, false},
-		{TimeFormatUnixMicro, "abc", time.Time{}, 0, true},
-		{TimeFormatUnixMicro, false, time.Time{}, 0, true},
-
-		{TimeFormatUnixNano, "1381134199120000000", reference, 0, false},
-		{TimeFormatUnixNano, 1381134199.120e9, reference, 0, false},
-		{TimeFormatUnixNano, int64(1381134199_120000000), reference, 0, false},
-		{TimeFormatUnixNano, "abc", time.Time{}, 0, true},
-		{TimeFormatUnixNano, false, time.Time{}, 0, true},
-
-		{TimeFormatAuto, "2456572.849526851851852", reference, time.Millisecond, false},
-		{TimeFormatAuto, "2456572", reference, 24 * time.Hour, false},
-		{TimeFormatAuto, "1381134199.120", reference, time.Microsecond, false},
-		{TimeFormatAuto, "1381134199.120e3", reference, time.Microsecond, false},
-		{TimeFormatAuto, "1381134199.120e6", reference, time.Microsecond, false},
-		{TimeFormatAuto, "1381134199.120e9", reference, time.Microsecond, false},
-		{TimeFormatAuto, "1381134199", reference, time.Second, false},
-		{TimeFormatAuto, "1381134199120", reference, 0, false},
-		{TimeFormatAuto, "1381134199120000", reference, 0, false},
-		{TimeFormatAuto, "1381134199120000000", reference, 0, false},
-		{TimeFormatAuto, "2013-10-07 04:23:19.12-04:00", reference, 0, false},
-		{TimeFormatAuto, "04:23:19.12-04:00", reftime, 0, false},
-		{TimeFormatAuto, "abc", time.Time{}, 0, true},
-		{TimeFormatAuto, false, time.Time{}, 0, true},
-
-		{TimeFormat3, "2013-10-07 04:23:19.12-04:00", reference, 0, false},
-		{TimeFormat3, "2013-10-07 08:23:19.12", reference, 0, false},
-		{TimeFormat9, "04:23:19.12-04:00", reftime, 0, false},
-		{TimeFormat9, "08:23:19.12", reftime, 0, false},
-		{TimeFormat3, false, time.Time{}, 0, true},
-		{TimeFormat9, false, time.Time{}, 0, true},
-
-		{TimeFormatDefault, "2013-10-07T04:23:19.12-04:00", reference, 0, false},
-		{TimeFormatDefault, "2013-10-07T08:23:19.12Z", reference, 0, false},
-		{TimeFormatDefault, false, time.Time{}, 0, true},
-	}
-
-	for _, tt := range tests {
-		t.Run("", func(t *testing.T) {
-			got, err := tt.fmt.Decode(tt.val)
-			if (err != nil) != tt.wantErr {
-				t.Errorf("%q.Decode(%v) error = %v, wantErr %v", tt.fmt, tt.val, err, tt.wantErr)
-				return
-			}
-			if tt.want.Sub(got).Abs() > tt.wantDelta {
-				t.Errorf("%q.Decode(%v) = %v, want %v", tt.fmt, tt.val, got, tt.want)
-			}
-		})
-	}
-}

tx.go

@@ -4,9 +4,14 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"math/rand"
 	"runtime"
+	"strconv"
 )
 
+// Tx is an in-progress database transaction.
+//
+// https://www.sqlite.org/lang_transaction.html
 type Tx struct {
 	c *Conn
 }
@@ -15,8 +20,9 @@ type Tx struct {
 //
 // https://www.sqlite.org/lang_transaction.html
 func (c *Conn) Begin() Tx {
-	err := c.Exec(`BEGIN DEFERRED`)
-	if err != nil && !errors.Is(err, INTERRUPT) {
+	// BEGIN even if interrupted.
+	err := c.txExecInterrupted(`BEGIN DEFERRED`)
+	if err != nil {
 		panic(err)
 	}
 	return Tx{c}
@@ -63,21 +69,22 @@ func (tx Tx) End(errp *error) {
 		defer panic(recovered)
 	}
 
-	if tx.c.GetAutocommit() {
-		// There is nothing to commit/rollback.
-		return
-	}
-
 	if *errp == nil && recovered == nil {
 		// Success path.
+		if tx.c.GetAutocommit() { // There is nothing to commit.
+			return
+		}
 		*errp = tx.Commit()
 		if *errp == nil {
 			return
 		}
-		// Possible interrupt, fall through to the error path.
+		// Fall through to the error path.
 	}
 
 	// Error path.
+	if tx.c.GetAutocommit() { // There is nothing to rollback.
+		return
+	}
 	err := tx.Rollback()
 	if err != nil {
 		panic(err)
@@ -91,33 +98,28 @@ func (tx Tx) Commit() error {
 	return tx.c.Exec(`COMMIT`)
 }
 
-// Rollback rollsback the transaction.
+// Rollback rolls back the transaction,
+// even if the connection has been interrupted.
 //
 // https://www.sqlite.org/lang_transaction.html
 func (tx Tx) Rollback() error {
-	// ROLLBACK even if the connection has been interrupted.
-	old := tx.c.SetInterrupt(context.Background())
-	defer tx.c.SetInterrupt(old)
-	return tx.c.Exec(`ROLLBACK`)
+	return tx.c.txExecInterrupted(`ROLLBACK`)
 }
 
-// Savepoint creates a named SQLite transaction using SAVEPOINT.
-//
-// On success Savepoint returns a release func that will call either
-// RELEASE or ROLLBACK depending on whether the parameter *error
-// points to a nil or non-nil error.
-//
-// This is meant to be deferred:
-//
-//	func doWork(conn *sqlite3.Conn) (err error) {
-//		defer conn.Savepoint()(&err)
-//
-//		// ... do work in the transaction
-//	}
+// Savepoint is a marker within a transaction
+// that allows for partial rollback.
 //
 // https://www.sqlite.org/lang_savepoint.html
-func (c *Conn) Savepoint() (release func(*error)) {
-	name := "sqlite3.Savepoint" // names can be reused
+type Savepoint struct {
+	c    *Conn
+	name string
+}
+
+// Savepoint establishes a new transaction savepoint.
+//
+// https://www.sqlite.org/lang_savepoint.html
+func (c *Conn) Savepoint() Savepoint {
+	name := "sqlite3.Savepoint"
 	var pc [1]uintptr
 	if n := runtime.Callers(2, pc[:]); n > 0 {
 		frames := runtime.CallersFrames(pc[:n])
@@ -126,52 +128,75 @@ func (c *Conn) Savepoint() (release func(*error)) {
 			name = frame.Function
 		}
 	}
+	// Names can be reused; this makes catching bugs more likely.
+	name += "#" + strconv.Itoa(int(rand.Int31()))
 
-	err := c.Exec(fmt.Sprintf("SAVEPOINT %q;", name))
+	err := c.txExecInterrupted(fmt.Sprintf("SAVEPOINT %q;", name))
 	if err != nil {
-		if errors.Is(err, INTERRUPT) {
-			return func(errp *error) {
-				if *errp == nil {
-					*errp = err
-				}
-			}
-		}
 		panic(err)
 	}
+	return Savepoint{c: c, name: name}
+}
 
-	return func(errp *error) {
-		recovered := recover()
-		if recovered != nil {
-			defer panic(recovered)
-		}
+// Release releases the savepoint rolling back any changes
+// if *error points to a non-nil error.
+//
+// This is meant to be deferred:
+//
+//	func doWork(conn *sqlite3.Conn) (err error) {
+//		savept := conn.Savepoint()
+//		defer savept.Release(&err)
+//
+//		// ... do work in the transaction
+//	}
+func (s Savepoint) Release(errp *error) {
+	recovered := recover()
+	if recovered != nil {
+		defer panic(recovered)
+	}
 
-		if c.GetAutocommit() {
-			// There is nothing to commit/rollback.
+	if *errp == nil && recovered == nil {
+		// Success path.
+		if s.c.GetAutocommit() { // There is nothing to commit.
 			return
 		}
-
-		if *errp == nil && recovered == nil {
-			// Success path.
-			// RELEASE the savepoint successfully.
-			*errp = c.Exec(fmt.Sprintf("RELEASE %q;", name))
-			if *errp == nil {
-				return
-			}
-			// Possible interrupt, fall through to the error path.
+		*errp = s.c.Exec(fmt.Sprintf("RELEASE %q;", s.name))
+		if *errp == nil {
+			return
 		}
+		// Fall through to the error path.
+	}
 
-		// Error path.
-		// Always ROLLBACK even if the connection has been interrupted.
-		old := c.SetInterrupt(context.Background())
-		defer c.SetInterrupt(old)
-
-		err := c.Exec(fmt.Sprintf("ROLLBACK TO %q;", name))
-		if err != nil {
-			panic(err)
-		}
-		err = c.Exec(fmt.Sprintf("RELEASE %q;", name))
-		if err != nil {
-			panic(err)
-		}
+	// Error path.
+	if s.c.GetAutocommit() { // There is nothing to rollback.
+		return
+	}
+	// ROLLBACK and RELEASE even if interrupted.
+	err := s.c.txExecInterrupted(fmt.Sprintf(`
+		ROLLBACK TO %[1]q;
+		RELEASE %[1]q;
+	`, s.name))
+	if err != nil {
+		panic(err)
 	}
 }
+
+// Rollback rolls the transaction back to the savepoint,
+// even if the connection has been interrupted.
+// Rollback does not release the savepoint.
+//
+// https://www.sqlite.org/lang_transaction.html
+func (s Savepoint) Rollback() error {
+	// ROLLBACK even if interrupted.
+	return s.c.txExecInterrupted(fmt.Sprintf("ROLLBACK TO %q;", s.name))
+}
+
+func (c *Conn) txExecInterrupted(sql string) error {
+	err := c.Exec(sql)
+	if errors.Is(err, INTERRUPT) {
+		old := c.SetInterrupt(context.Background())
+		defer c.SetInterrupt(old)
+		err = c.Exec(sql)
+	}
+	return err
+}

vfs.go

@@ -1,318 +0,0 @@
-package sqlite3
-
-import (
-	"context"
-	"crypto/rand"
-	"errors"
-	"io"
-	"io/fs"
-	"os"
-	"path/filepath"
-	"runtime"
-	"syscall"
-	"time"
-
-	"github.com/ncruces/julianday"
-	"github.com/tetratelabs/wazero"
-	"github.com/tetratelabs/wazero/api"
-	"github.com/tetratelabs/wazero/sys"
-)
-
-func vfsInstantiate(ctx context.Context, r wazero.Runtime) {
-	wasi := r.NewHostModuleBuilder("wasi_snapshot_preview1")
-	wasi.NewFunctionBuilder().WithFunc(vfsExit).Export("proc_exit")
-	_, err := wasi.Instantiate(ctx)
-	if err != nil {
-		panic(err)
-	}
-
-	env := r.NewHostModuleBuilder("env")
-	env.NewFunctionBuilder().WithFunc(vfsLocaltime).Export("os_localtime")
-	env.NewFunctionBuilder().WithFunc(vfsRandomness).Export("os_randomness")
-	env.NewFunctionBuilder().WithFunc(vfsSleep).Export("os_sleep")
-	env.NewFunctionBuilder().WithFunc(vfsCurrentTime).Export("os_current_time")
-	env.NewFunctionBuilder().WithFunc(vfsCurrentTime64).Export("os_current_time_64")
-	env.NewFunctionBuilder().WithFunc(vfsFullPathname).Export("os_full_pathname")
-	env.NewFunctionBuilder().WithFunc(vfsDelete).Export("os_delete")
-	env.NewFunctionBuilder().WithFunc(vfsAccess).Export("os_access")
-	env.NewFunctionBuilder().WithFunc(vfsOpen).Export("os_open")
-	env.NewFunctionBuilder().WithFunc(vfsClose).Export("os_close")
-	env.NewFunctionBuilder().WithFunc(vfsRead).Export("os_read")
-	env.NewFunctionBuilder().WithFunc(vfsWrite).Export("os_write")
-	env.NewFunctionBuilder().WithFunc(vfsTruncate).Export("os_truncate")
-	env.NewFunctionBuilder().WithFunc(vfsSync).Export("os_sync")
-	env.NewFunctionBuilder().WithFunc(vfsFileSize).Export("os_file_size")
-	env.NewFunctionBuilder().WithFunc(vfsLock).Export("os_lock")
-	env.NewFunctionBuilder().WithFunc(vfsUnlock).Export("os_unlock")
-	env.NewFunctionBuilder().WithFunc(vfsCheckReservedLock).Export("os_check_reserved_lock")
-	env.NewFunctionBuilder().WithFunc(vfsFileControl).Export("os_file_control")
-	_, err = env.Instantiate(ctx)
-	if err != nil {
-		panic(err)
-	}
-}
-
-type vfsOSMethods bool
-
-const vfsOS vfsOSMethods = false
-
-func vfsExit(ctx context.Context, mod api.Module, exitCode uint32) {
-	// Ensure other callers see the exit code.
-	_ = mod.CloseWithExitCode(ctx, exitCode)
-	// Prevent any code from executing after this function.
-	panic(sys.NewExitError(mod.Name(), exitCode))
-}
-
-func vfsLocaltime(ctx context.Context, mod api.Module, t uint64, pTm uint32) uint32 {
-	tm := time.Unix(int64(t), 0)
-	var isdst int
-	if tm.IsDST() {
-		isdst = 1
-	}
-
-	// https://pubs.opengroup.org/onlinepubs/7908799/xsh/time.h.html
-	mem := memory{mod}
-	mem.writeUint32(pTm+0*ptrlen, uint32(tm.Second()))
-	mem.writeUint32(pTm+1*ptrlen, uint32(tm.Minute()))
-	mem.writeUint32(pTm+2*ptrlen, uint32(tm.Hour()))
-	mem.writeUint32(pTm+3*ptrlen, uint32(tm.Day()))
-	mem.writeUint32(pTm+4*ptrlen, uint32(tm.Month()-time.January))
-	mem.writeUint32(pTm+5*ptrlen, uint32(tm.Year()-1900))
-	mem.writeUint32(pTm+6*ptrlen, uint32(tm.Weekday()-time.Sunday))
-	mem.writeUint32(pTm+7*ptrlen, uint32(tm.YearDay()-1))
-	mem.writeUint32(pTm+8*ptrlen, uint32(isdst))
-	return _OK
-}
-
-func vfsRandomness(ctx context.Context, mod api.Module, pVfs, nByte, zByte uint32) uint32 {
-	mem := memory{mod}.view(zByte, uint64(nByte))
-	n, _ := rand.Reader.Read(mem)
-	return uint32(n)
-}
-
-func vfsSleep(ctx context.Context, pVfs, nMicro uint32) uint32 {
-	time.Sleep(time.Duration(nMicro) * time.Microsecond)
-	return _OK
-}
-
-func vfsCurrentTime(ctx context.Context, mod api.Module, pVfs, prNow uint32) uint32 {
-	day := julianday.Float(time.Now())
-	memory{mod}.writeFloat64(prNow, day)
-	return _OK
-}
-
-func vfsCurrentTime64(ctx context.Context, mod api.Module, pVfs, piNow uint32) uint32 {
-	day, nsec := julianday.Date(time.Now())
-	msec := day*86_400_000 + nsec/1_000_000
-	memory{mod}.writeUint64(piNow, uint64(msec))
-	return _OK
-}
-
-func vfsFullPathname(ctx context.Context, mod api.Module, pVfs, zRelative, nFull, zFull uint32) uint32 {
-	rel := memory{mod}.readString(zRelative, _MAX_PATHNAME)
-	abs, err := filepath.Abs(rel)
-	if err != nil {
-		return uint32(IOERR)
-	}
-
-	// Consider either using [filepath.EvalSymlinks] to canonicalize the path (as the Unix VFS does).
-	// Or using [os.Readlink] to resolve a symbolic link (as the Unix VFS did).
-	// This might be buggy on Windows (the Windows VFS doesn't try).
-
-	size := uint64(len(abs) + 1)
-	if size > uint64(nFull) {
-		return uint32(CANTOPEN_FULLPATH)
-	}
-	mem := memory{mod}.view(zFull, size)
-
-	mem[len(abs)] = 0
-	copy(mem, abs)
-	return _OK
-}
-
-func vfsDelete(ctx context.Context, mod api.Module, pVfs, zPath, syncDir uint32) uint32 {
-	path := memory{mod}.readString(zPath, _MAX_PATHNAME)
-	err := os.Remove(path)
-	if errors.Is(err, fs.ErrNotExist) {
-		return _OK
-	}
-	if err != nil {
-		return uint32(IOERR_DELETE)
-	}
-	if runtime.GOOS != "windows" && syncDir != 0 {
-		f, err := os.Open(filepath.Dir(path))
-		if err == nil {
-			err = f.Sync()
-			f.Close()
-		}
-		if err != nil {
-			return uint32(IOERR_DELETE)
-		}
-	}
-	return _OK
-}
-
-func vfsAccess(ctx context.Context, mod api.Module, pVfs, zPath uint32, flags _AccessFlag, pResOut uint32) uint32 {
-	// Consider using [syscall.Access] for [ACCESS_READWRITE]/[ACCESS_READ]
-	// (as the Unix VFS does).
-
-	path := memory{mod}.readString(zPath, _MAX_PATHNAME)
-	fi, err := os.Stat(path)
-
-	var res uint32
-	switch {
-	case flags == _ACCESS_EXISTS:
-		switch {
-		case err == nil:
-			res = 1
-		case errors.Is(err, fs.ErrNotExist):
-			res = 0
-		default:
-			return uint32(IOERR_ACCESS)
-		}
-
-	case err == nil:
-		var want fs.FileMode = syscall.S_IRUSR
-		if flags == _ACCESS_READWRITE {
-			want |= syscall.S_IWUSR
-		}
-		if fi.IsDir() {
-			want |= syscall.S_IXUSR
-		}
-		if fi.Mode()&want == want {
-			res = 1
-		} else {
-			res = 0
-		}
-
-	case errors.Is(err, fs.ErrPermission):
-		res = 0
-
-	default:
-		return uint32(IOERR_ACCESS)
-	}
-
-	memory{mod}.writeUint32(pResOut, res)
-	return _OK
-}
-
-func vfsOpen(ctx context.Context, mod api.Module, pVfs, zName, pFile uint32, flags OpenFlag, pOutFlags uint32) uint32 {
-	var oflags int
-	if flags&OPEN_EXCLUSIVE != 0 {
-		oflags |= os.O_EXCL
-	}
-	if flags&OPEN_CREATE != 0 {
-		oflags |= os.O_CREATE
-	}
-	if flags&OPEN_READONLY != 0 {
-		oflags |= os.O_RDONLY
-	}
-	if flags&OPEN_READWRITE != 0 {
-		oflags |= os.O_RDWR
-	}
-
-	var err error
-	var file *os.File
-	if zName == 0 {
-		file, err = os.CreateTemp("", "*.db")
-	} else {
-		name := memory{mod}.readString(zName, _MAX_PATHNAME)
-		file, err = os.OpenFile(name, oflags, 0600)
-	}
-	if err != nil {
-		return uint32(CANTOPEN)
-	}
-
-	if flags&OPEN_DELETEONCLOSE != 0 {
-		vfsOS.DeleteOnClose(file)
-	}
-
-	id := vfsGetFileID(file)
-	vfsFilePtr{mod, pFile}.SetID(id).SetLock(_NO_LOCK)
-
-	if pOutFlags != 0 {
-		memory{mod}.writeUint32(pOutFlags, uint32(flags))
-	}
-	return _OK
-}
-
-func vfsClose(ctx context.Context, mod api.Module, pFile uint32) uint32 {
-	id := vfsFilePtr{mod, pFile}.ID()
-	err := vfsCloseFile(id)
-	if err != nil {
-		return uint32(IOERR_CLOSE)
-	}
-	return _OK
-}
-
-func vfsRead(ctx context.Context, mod api.Module, pFile, zBuf, iAmt uint32, iOfst uint64) uint32 {
-	buf := memory{mod}.view(zBuf, uint64(iAmt))
-
-	file := vfsFilePtr{mod, pFile}.OSFile()
-	n, err := file.ReadAt(buf, int64(iOfst))
-	if n == int(iAmt) {
-		return _OK
-	}
-	if n == 0 && err != io.EOF {
-		return uint32(IOERR_READ)
-	}
-	for i := range buf[n:] {
-		buf[n+i] = 0
-	}
-	return uint32(IOERR_SHORT_READ)
-}
-
-func vfsWrite(ctx context.Context, mod api.Module, pFile, zBuf, iAmt uint32, iOfst uint64) uint32 {
-	buf := memory{mod}.view(zBuf, uint64(iAmt))
-
-	file := vfsFilePtr{mod, pFile}.OSFile()
-	_, err := file.WriteAt(buf, int64(iOfst))
-	if err != nil {
-		return uint32(IOERR_WRITE)
-	}
-	return _OK
-}
-
-func vfsTruncate(ctx context.Context, mod api.Module, pFile uint32, nByte uint64) uint32 {
-	file := vfsFilePtr{mod, pFile}.OSFile()
-	err := file.Truncate(int64(nByte))
-	if err != nil {
-		return uint32(IOERR_TRUNCATE)
-	}
-	return _OK
-}
-
-func vfsSync(ctx context.Context, mod api.Module, pFile, flags uint32) uint32 {
-	file := vfsFilePtr{mod, pFile}.OSFile()
-	err := file.Sync()
-	if err != nil {
-		return uint32(IOERR_FSYNC)
-	}
-	return _OK
-}
-
-func vfsFileSize(ctx context.Context, mod api.Module, pFile, pSize uint32) uint32 {
-	// This uses [os.File.Seek] because we don't care about the offset for reading/writing.
-	// But consider using [os.File.Stat] instead (as other VFSes do).
-
-	file := vfsFilePtr{mod, pFile}.OSFile()
-	off, err := file.Seek(0, io.SeekEnd)
-	if err != nil {
-		return uint32(IOERR_SEEK)
-	}
-
-	memory{mod}.writeUint64(pSize, uint64(off))
-	return _OK
-}
-
-func vfsFileControl(ctx context.Context, pFile, op, pArg uint32) uint32 {
-	// SQLite calls vfsFileControl with these opcodes:
-	//  SQLITE_FCNTL_SIZE_HINT
-	//  SQLITE_FCNTL_PRAGMA
-	//  SQLITE_FCNTL_BUSYHANDLER
-	//  SQLITE_FCNTL_HAS_MOVED
-	//  SQLITE_FCNTL_SYNC
-	//  SQLITE_FCNTL_COMMIT_PHASETWO
-	//  SQLITE_FCNTL_PDB
-	return uint32(NOTFOUND)
-}

vfs_files.go

@@ -1,69 +0,0 @@
-package sqlite3
-
-import (
-	"os"
-	"sync"
-
-	"github.com/tetratelabs/wazero/api"
-)
-
-var (
-	vfsOpenFiles    []*os.File
-	vfsOpenFilesMtx sync.Mutex
-)
-
-func vfsGetFileID(file *os.File) uint32 {
-	vfsOpenFilesMtx.Lock()
-	defer vfsOpenFilesMtx.Unlock()
-
-	// Find an empty slot.
-	for id, ptr := range vfsOpenFiles {
-		if ptr == nil {
-			vfsOpenFiles[id] = file
-			return uint32(id)
-		}
-	}
-
-	// Add a new slot.
-	vfsOpenFiles = append(vfsOpenFiles, file)
-	return uint32(len(vfsOpenFiles) - 1)
-}
-
-func vfsCloseFile(id uint32) error {
-	vfsOpenFilesMtx.Lock()
-	defer vfsOpenFilesMtx.Unlock()
-
-	file := vfsOpenFiles[id]
-	vfsOpenFiles[id] = nil
-	return file.Close()
-}
-
-type vfsFilePtr struct {
-	api.Module
-	ptr uint32
-}
-
-func (p vfsFilePtr) OSFile() *os.File {
-	id := p.ID()
-	vfsOpenFilesMtx.Lock()
-	defer vfsOpenFilesMtx.Unlock()
-	return vfsOpenFiles[id]
-}
-
-func (p vfsFilePtr) ID() uint32 {
-	return memory{p}.readUint32(p.ptr + ptrlen)
-}
-
-func (p vfsFilePtr) Lock() vfsLockState {
-	return vfsLockState(memory{p}.readUint32(p.ptr + 2*ptrlen))
-}
-
-func (p vfsFilePtr) SetID(id uint32) vfsFilePtr {
-	memory{p}.writeUint32(p.ptr+ptrlen, id)
-	return p
-}
-
-func (p vfsFilePtr) SetLock(lock vfsLockState) vfsFilePtr {
-	memory{p}.writeUint32(p.ptr+2*ptrlen, uint32(lock))
-	return p
-}

vfs_lock.go

@@ -1,215 +0,0 @@
-package sqlite3
-
-import (
-	"context"
-	"os"
-
-	"github.com/tetratelabs/wazero/api"
-)
-
-const (
-	// No locks are held on the database.
-	// The database may be neither read nor written.
-	// Any internally cached data is considered suspect and subject to
-	// verification against the database file before being used.
-	// Other processes can read or write the database as their own locking
-	// states permit.
-	// This is the default state.
-	_NO_LOCK = 0
-
-	// The database may be read but not written.
-	// Any number of processes can hold SHARED locks at the same time,
-	// hence there can be many simultaneous readers.
-	// But no other thread or process is allowed to write to the database file
-	// while one or more SHARED locks are active.
-	_SHARED_LOCK = 1
-
-	// A RESERVED lock means that the process is planning on writing to the
-	// database file at some point in the future but that it is currently just
-	// reading from the file.
-	// Only a single RESERVED lock may be active at one time,
-	// though multiple SHARED locks can coexist with a single RESERVED lock.
-	// RESERVED differs from PENDING in that new SHARED locks can be acquired
-	// while there is a RESERVED lock.
-	_RESERVED_LOCK = 2
-
-	// A PENDING lock means that the process holding the lock wants to write to
-	// the database as soon as possible and is just waiting on all current
-	// SHARED locks to clear so that it can get an EXCLUSIVE lock.
-	// No new SHARED locks are permitted against the database if a PENDING lock
-	// is active, though existing SHARED locks are allowed to continue.
-	_PENDING_LOCK = 3
-
-	// An EXCLUSIVE lock is needed in order to write to the database file.
-	// Only one EXCLUSIVE lock is allowed on the file and no other locks of any
-	// kind are allowed to coexist with an EXCLUSIVE lock.
-	// In order to maximize concurrency, SQLite works to minimize the amount of
-	// time that EXCLUSIVE locks are held.
-	_EXCLUSIVE_LOCK = 4
-
-	_PENDING_BYTE  = 0x40000000
-	_RESERVED_BYTE = (_PENDING_BYTE + 1)
-	_SHARED_FIRST  = (_PENDING_BYTE + 2)
-	_SHARED_SIZE   = 510
-)
-
-type vfsLockState uint32
-
-func vfsLock(ctx context.Context, mod api.Module, pFile uint32, eLock vfsLockState) uint32 {
-	// Argument check. SQLite never explicitly requests a pendig lock.
-	if eLock != _SHARED_LOCK && eLock != _RESERVED_LOCK && eLock != _EXCLUSIVE_LOCK {
-		panic(assertErr())
-	}
-
-	ptr := vfsFilePtr{mod, pFile}
-	file := ptr.OSFile()
-	cLock := ptr.Lock()
-
-	switch {
-	case cLock < _NO_LOCK || cLock > _EXCLUSIVE_LOCK:
-		// Connection state check.
-		panic(assertErr())
-	case cLock == _NO_LOCK && eLock > _SHARED_LOCK:
-		// We never move from unlocked to anything higher than a shared lock.
-		panic(assertErr())
-	case cLock != _SHARED_LOCK && eLock == _RESERVED_LOCK:
-		// A shared lock is always held when a reserved lock is requested.
-		panic(assertErr())
-	}
-
-	// If we already have an equal or more restrictive lock, do nothing.
-	if cLock >= eLock {
-		return _OK
-	}
-
-	switch eLock {
-	case _SHARED_LOCK:
-		// Must be unlocked to get SHARED.
-		if cLock != _NO_LOCK {
-			panic(assertErr())
-		}
-		// Test the PENDING lock before acquiring a new SHARED lock.
-		if locked, _ := vfsOS.CheckPendingLock(file); locked {
-			return uint32(BUSY)
-		}
-		if rc := vfsOS.GetSharedLock(file); rc != _OK {
-			return uint32(rc)
-		}
-		ptr.SetLock(_SHARED_LOCK)
-		return _OK
-
-	case _RESERVED_LOCK:
-		// Must be SHARED to get RESERVED.
-		if cLock != _SHARED_LOCK {
-			panic(assertErr())
-		}
-		if rc := vfsOS.GetReservedLock(file); rc != _OK {
-			return uint32(rc)
-		}
-		ptr.SetLock(_RESERVED_LOCK)
-		return _OK
-
-	case _EXCLUSIVE_LOCK:
-		// Must be SHARED, RESERVED or PENDING to get EXCLUSIVE.
-		if cLock <= _NO_LOCK || cLock >= _EXCLUSIVE_LOCK {
-			panic(assertErr())
-		}
-		// A PENDING lock is needed before acquiring an EXCLUSIVE lock.
-		if cLock == _RESERVED_LOCK {
-			if rc := vfsOS.GetPendingLock(file); rc != _OK {
-				return uint32(rc)
-			}
-			ptr.SetLock(_PENDING_LOCK)
-		}
-		if rc := vfsOS.GetExclusiveLock(file); rc != _OK {
-			return uint32(rc)
-		}
-		ptr.SetLock(_EXCLUSIVE_LOCK)
-		return _OK
-
-	default:
-		panic(assertErr())
-	}
-}
-
-func vfsUnlock(ctx context.Context, mod api.Module, pFile uint32, eLock vfsLockState) uint32 {
-	// Argument check.
-	if eLock != _NO_LOCK && eLock != _SHARED_LOCK {
-		panic(assertErr())
-	}
-
-	ptr := vfsFilePtr{mod, pFile}
-	file := ptr.OSFile()
-	cLock := ptr.Lock()
-
-	// Connection state check.
-	if cLock < _NO_LOCK || cLock > _EXCLUSIVE_LOCK {
-		panic(assertErr())
-	}
-
-	// If we don't have a more restrictive lock, do nothing.
-	if cLock <= eLock {
-		return _OK
-	}
-
-	switch eLock {
-	case _SHARED_LOCK:
-		if rc := vfsOS.DowngradeLock(file, cLock); rc != _OK {
-			return uint32(rc)
-		}
-		ptr.SetLock(_SHARED_LOCK)
-		return _OK
-
-	case _NO_LOCK:
-		rc := vfsOS.ReleaseLock(file, cLock)
-		ptr.SetLock(_NO_LOCK)
-		return uint32(rc)
-
-	default:
-		panic(assertErr())
-	}
-}
-
-func vfsCheckReservedLock(ctx context.Context, mod api.Module, pFile, pResOut uint32) uint32 {
-	ptr := vfsFilePtr{mod, pFile}
-	cLock := ptr.Lock()
-
-	if cLock > _SHARED_LOCK {
-		panic(assertErr())
-	}
-
-	file := ptr.OSFile()
-
-	locked, rc := vfsOS.CheckReservedLock(file)
-	var res uint32
-	if locked {
-		res = 1
-	}
-	memory{mod}.writeUint32(pResOut, res)
-	return uint32(rc)
-}
-
-func (vfsOSMethods) GetSharedLock(file *os.File) xErrorCode {
-	// Acquire the SHARED lock.
-	return vfsOS.readLock(file, _SHARED_FIRST, _SHARED_SIZE)
-}
-
-func (vfsOSMethods) GetReservedLock(file *os.File) xErrorCode {
-	// Acquire the RESERVED lock.
-	return vfsOS.writeLock(file, _RESERVED_BYTE, 1)
-}
-
-func (vfsOSMethods) GetPendingLock(file *os.File) xErrorCode {
-	// Acquire the PENDING lock.
-	return vfsOS.writeLock(file, _PENDING_BYTE, 1)
-}
-
-func (vfsOSMethods) CheckReservedLock(file *os.File) (bool, xErrorCode) {
-	// Test the RESERVED lock.
-	return vfsOS.checkLock(file, _RESERVED_BYTE, 1)
-}
-
-func (vfsOSMethods) CheckPendingLock(file *os.File) (bool, xErrorCode) {
-	// Test the PENDING lock.
-	return vfsOS.checkLock(file, _PENDING_BYTE, 1)
-}

vfs_lock_test.go

@@ -1,125 +0,0 @@
-package sqlite3
-
-import (
-	"context"
-	"os"
-	"path/filepath"
-	"runtime"
-	"testing"
-)
-
-func Test_vfsLock(t *testing.T) {
-	switch runtime.GOOS {
-	case "linux", "darwin", "illumos", "windows":
-		break
-	default:
-		t.Skip("OS lacks OFD locks")
-	}
-
-	name := filepath.Join(t.TempDir(), "test.db")
-
-	// Create a temporary file.
-	file1, err := os.OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0666)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer file1.Close()
-
-	// Open the temporary file again.
-	file2, err := os.OpenFile(name, os.O_RDWR, 0)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer file2.Close()
-
-	const (
-		pFile1  = 4
-		pFile2  = 16
-		pOutput = 32
-	)
-	mem := newMemory(128)
-	vfsFilePtr{mem.mod, pFile1}.SetID(vfsGetFileID(file1)).SetLock(_NO_LOCK)
-	vfsFilePtr{mem.mod, pFile2}.SetID(vfsGetFileID(file2)).SetLock(_NO_LOCK)
-
-	rc := vfsCheckReservedLock(context.TODO(), mem.mod, pFile1, pOutput)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-	if got := mem.readUint32(pOutput); got != 0 {
-		t.Error("file was locked")
-	}
-
-	rc = vfsLock(context.TODO(), mem.mod, pFile2, _SHARED_LOCK)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-
-	rc = vfsCheckReservedLock(context.TODO(), mem.mod, pFile1, pOutput)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-	if got := mem.readUint32(pOutput); got != 0 {
-		t.Error("file was locked")
-	}
-
-	rc = vfsLock(context.TODO(), mem.mod, pFile2, _RESERVED_LOCK)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-	rc = vfsLock(context.TODO(), mem.mod, pFile2, _SHARED_LOCK)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-
-	rc = vfsCheckReservedLock(context.TODO(), mem.mod, pFile1, pOutput)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-	if got := mem.readUint32(pOutput); got == 0 {
-		t.Error("file wasn't locked")
-	}
-
-	rc = vfsLock(context.TODO(), mem.mod, pFile2, _EXCLUSIVE_LOCK)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-
-	rc = vfsCheckReservedLock(context.TODO(), mem.mod, pFile1, pOutput)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-	if got := mem.readUint32(pOutput); got == 0 {
-		t.Error("file wasn't locked")
-	}
-
-	rc = vfsLock(context.TODO(), mem.mod, pFile1, _SHARED_LOCK)
-	if rc == _OK {
-		t.Fatal("returned", rc)
-	}
-
-	rc = vfsCheckReservedLock(context.TODO(), mem.mod, pFile1, pOutput)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-	if got := mem.readUint32(pOutput); got == 0 {
-		t.Error("file wasn't locked")
-	}
-
-	rc = vfsUnlock(context.TODO(), mem.mod, pFile2, _SHARED_LOCK)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-
-	rc = vfsCheckReservedLock(context.TODO(), mem.mod, pFile1, pOutput)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-	if got := mem.readUint32(pOutput); got != 0 {
-		t.Error("file was locked")
-	}
-
-	rc = vfsLock(context.TODO(), mem.mod, pFile1, _SHARED_LOCK)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-}

vfs_test.go

@@ -1,271 +0,0 @@
-package sqlite3
-
-import (
-	"bytes"
-	"context"
-	"errors"
-	"io/fs"
-	"os"
-	"path/filepath"
-	"syscall"
-	"testing"
-	"time"
-
-	"github.com/ncruces/julianday"
-)
-
-func Test_vfsExit(t *testing.T) {
-	mem := newMemory(128)
-	defer func() { _ = recover() }()
-	vfsExit(context.TODO(), mem.mod, 1)
-	t.Error("want panic")
-}
-
-func Test_vfsLocaltime(t *testing.T) {
-	mem := newMemory(128)
-
-	rc := vfsLocaltime(context.TODO(), mem.mod, 0, 4)
-	if rc != 0 {
-		t.Fatal("returned", rc)
-	}
-
-	epoch := time.Unix(0, 0)
-	if s := mem.readUint32(4 + 0*4); int(s) != epoch.Second() {
-		t.Error("wrong second")
-	}
-	if m := mem.readUint32(4 + 1*4); int(m) != epoch.Minute() {
-		t.Error("wrong minute")
-	}
-	if h := mem.readUint32(4 + 2*4); int(h) != epoch.Hour() {
-		t.Error("wrong hour")
-	}
-	if d := mem.readUint32(4 + 3*4); int(d) != epoch.Day() {
-		t.Error("wrong day")
-	}
-	if m := mem.readUint32(4 + 4*4); time.Month(1+m) != epoch.Month() {
-		t.Error("wrong month")
-	}
-	if y := mem.readUint32(4 + 5*4); 1900+int(y) != epoch.Year() {
-		t.Error("wrong year")
-	}
-	if w := mem.readUint32(4 + 6*4); time.Weekday(w) != epoch.Weekday() {
-		t.Error("wrong weekday")
-	}
-	if d := mem.readUint32(4 + 7*4); int(d) != epoch.YearDay()-1 {
-		t.Error("wrong yearday")
-	}
-}
-
-func Test_vfsRandomness(t *testing.T) {
-	mem := newMemory(128)
-
-	rc := vfsRandomness(context.TODO(), mem.mod, 0, 16, 4)
-	if rc != 16 {
-		t.Fatal("returned", rc)
-	}
-
-	var zero [16]byte
-	if got := mem.view(4, 16); bytes.Equal(got, zero[:]) {
-		t.Fatal("all zero")
-	}
-}
-
-func Test_vfsSleep(t *testing.T) {
-	start := time.Now()
-
-	rc := vfsSleep(context.TODO(), 0, 123456)
-	if rc != 0 {
-		t.Fatal("returned", rc)
-	}
-
-	want := 123456 * time.Microsecond
-	if got := time.Since(start); got < want {
-		t.Errorf("got %v, want %v", got, want)
-	}
-}
-
-func Test_vfsCurrentTime(t *testing.T) {
-	mem := newMemory(128)
-
-	now := time.Now()
-	rc := vfsCurrentTime(context.TODO(), mem.mod, 0, 4)
-	if rc != 0 {
-		t.Fatal("returned", rc)
-	}
-
-	want := julianday.Float(now)
-	if got := mem.readFloat64(4); float32(got) != float32(want) {
-		t.Errorf("got %v, want %v", got, want)
-	}
-}
-
-func Test_vfsCurrentTime64(t *testing.T) {
-	mem := newMemory(128)
-
-	now := time.Now()
-	time.Sleep(time.Millisecond)
-	rc := vfsCurrentTime64(context.TODO(), mem.mod, 0, 4)
-	if rc != 0 {
-		t.Fatal("returned", rc)
-	}
-
-	day, nsec := julianday.Date(now)
-	want := day*86_400_000 + nsec/1_000_000
-	if got := mem.readUint64(4); float32(got) != float32(want) {
-		t.Errorf("got %v, want %v", got, want)
-	}
-}
-
-func Test_vfsFullPathname(t *testing.T) {
-	mem := newMemory(128 + _MAX_PATHNAME)
-	mem.writeString(4, ".")
-
-	rc := vfsFullPathname(context.TODO(), mem.mod, 0, 4, 0, 8)
-	if rc != uint32(CANTOPEN_FULLPATH) {
-		t.Errorf("returned %d, want %d", rc, CANTOPEN_FULLPATH)
-	}
-
-	rc = vfsFullPathname(context.TODO(), mem.mod, 0, 4, _MAX_PATHNAME, 8)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-
-	want, _ := filepath.Abs(".")
-	if got := mem.readString(8, _MAX_PATHNAME); got != want {
-		t.Errorf("got %v, want %v", got, want)
-	}
-}
-
-func Test_vfsDelete(t *testing.T) {
-	name := filepath.Join(t.TempDir(), "test.db")
-
-	file, err := os.Create(name)
-	if err != nil {
-		t.Fatal(err)
-	}
-	file.Close()
-
-	mem := newMemory(128 + _MAX_PATHNAME)
-	mem.writeString(4, name)
-
-	rc := vfsDelete(context.TODO(), mem.mod, 0, 4, 1)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-
-	if _, err := os.Stat(name); !errors.Is(err, fs.ErrNotExist) {
-		t.Fatal("did not delete the file")
-	}
-
-	rc = vfsDelete(context.TODO(), mem.mod, 0, 4, 1)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-}
-
-func Test_vfsAccess(t *testing.T) {
-	dir := t.TempDir()
-	file := filepath.Join(t.TempDir(), "test.db")
-	if f, err := os.Create(file); err != nil {
-		t.Fatal(err)
-	} else {
-		f.Close()
-	}
-	if err := os.Chmod(file, syscall.S_IRUSR); err != nil {
-		t.Fatal(err)
-	}
-
-	mem := newMemory(128 + _MAX_PATHNAME)
-	mem.writeString(8, dir)
-
-	rc := vfsAccess(context.TODO(), mem.mod, 0, 8, _ACCESS_EXISTS, 4)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-	if got := mem.readUint32(4); got != 1 {
-		t.Error("directory did not exist")
-	}
-
-	rc = vfsAccess(context.TODO(), mem.mod, 0, 8, _ACCESS_READWRITE, 4)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-	if got := mem.readUint32(4); got != 1 {
-		t.Error("can't access directory")
-	}
-
-	mem.writeString(8, file)
-	rc = vfsAccess(context.TODO(), mem.mod, 0, 8, _ACCESS_READWRITE, 4)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-	if got := mem.readUint32(4); got != 0 {
-		t.Error("can access file")
-	}
-}
-
-func Test_vfsFile(t *testing.T) {
-	mem := newMemory(128)
-
-	// Open a temporary file.
-	rc := vfsOpen(context.TODO(), mem.mod, 0, 0, 4, OPEN_CREATE|OPEN_EXCLUSIVE|OPEN_READWRITE|OPEN_DELETEONCLOSE, 0)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-
-	// Write stuff.
-	text := "Hello world!"
-	mem.writeString(16, text)
-	rc = vfsWrite(context.TODO(), mem.mod, 4, 16, uint32(len(text)), 0)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-
-	// Check file size.
-	rc = vfsFileSize(context.TODO(), mem.mod, 4, 16)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-	if got := mem.readUint32(16); got != uint32(len(text)) {
-		t.Errorf("got %d", got)
-	}
-
-	// Partial read at offset.
-	rc = vfsRead(context.TODO(), mem.mod, 4, 16, uint32(len(text)), 4)
-	if rc != uint32(IOERR_SHORT_READ) {
-		t.Fatal("returned", rc)
-	}
-	if got := mem.readString(16, 64); got != text[4:] {
-		t.Errorf("got %q", got)
-	}
-
-	// Truncate the file.
-	rc = vfsTruncate(context.TODO(), mem.mod, 4, 4)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-
-	// Check file size.
-	rc = vfsFileSize(context.TODO(), mem.mod, 4, 16)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-	if got := mem.readUint32(16); got != 4 {
-		t.Errorf("got %d", got)
-	}
-
-	// Read at offset.
-	rc = vfsRead(context.TODO(), mem.mod, 4, 32, 4, 0)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-	if got := mem.readString(32, 64); got != text[:4] {
-		t.Errorf("got %q", got)
-	}
-
-	// Close the file.
-	rc = vfsClose(context.TODO(), mem.mod, 4)
-	if rc != _OK {
-		t.Fatal("returned", rc)
-	}
-}

vfs_unix.go

@@ -1,137 +0,0 @@
-//go:build unix
-
-package sqlite3
-
-import (
-	"os"
-	"runtime"
-	"syscall"
-)
-
-func (vfsOSMethods) DeleteOnClose(file *os.File) {
-	_ = os.Remove(file.Name())
-}
-
-func (vfsOSMethods) GetExclusiveLock(file *os.File) xErrorCode {
-	// Acquire the EXCLUSIVE lock.
-	return vfsOS.writeLock(file, _SHARED_FIRST, _SHARED_SIZE)
-}
-
-func (vfsOSMethods) DowngradeLock(file *os.File, state vfsLockState) xErrorCode {
-	if state >= _EXCLUSIVE_LOCK {
-		// Downgrade to a SHARED lock.
-		if rc := vfsOS.readLock(file, _SHARED_FIRST, _SHARED_SIZE); rc != _OK {
-			// In theory, the downgrade to a SHARED cannot fail because another
-			// process is holding an incompatible lock. If it does, this
-			// indicates that the other process is not following the locking
-			// protocol. If this happens, return IOERR_RDLOCK. Returning
-			// BUSY would confuse the upper layer.
-			return IOERR_RDLOCK
-		}
-	}
-	// Release the PENDING and RESERVED locks.
-	return vfsOS.unlock(file, _PENDING_BYTE, 2)
-}
-
-func (vfsOSMethods) ReleaseLock(file *os.File, _ vfsLockState) xErrorCode {
-	// Release all locks.
-	return vfsOS.unlock(file, 0, 0)
-}
-
-func (vfsOSMethods) unlock(file *os.File, start, len int64) xErrorCode {
-	err := vfsOS.fcntlSetLock(file, &syscall.Flock_t{
-		Type:  syscall.F_UNLCK,
-		Start: start,
-		Len:   len,
-	})
-	if err != nil {
-		return IOERR_UNLOCK
-	}
-	return _OK
-}
-
-func (vfsOSMethods) readLock(file *os.File, start, len int64) xErrorCode {
-	return vfsOS.lockErrorCode(vfsOS.fcntlSetLock(file, &syscall.Flock_t{
-		Type:  syscall.F_RDLCK,
-		Start: start,
-		Len:   len,
-	}), IOERR_RDLOCK)
-}
-
-func (vfsOSMethods) writeLock(file *os.File, start, len int64) xErrorCode {
-	return vfsOS.lockErrorCode(vfsOS.fcntlSetLock(file, &syscall.Flock_t{
-		Type:  syscall.F_WRLCK,
-		Start: start,
-		Len:   len,
-	}), IOERR_LOCK)
-}
-
-func (vfsOSMethods) checkLock(file *os.File, start, len int64) (bool, xErrorCode) {
-	lock := syscall.Flock_t{
-		Type:  syscall.F_RDLCK,
-		Start: start,
-		Len:   len,
-	}
-	if vfsOS.fcntlGetLock(file, &lock) != nil {
-		return false, IOERR_CHECKRESERVEDLOCK
-	}
-	return lock.Type != syscall.F_UNLCK, _OK
-}
-
-func (vfsOSMethods) fcntlGetLock(file *os.File, lock *syscall.Flock_t) error {
-	var F_OFD_GETLK int
-	switch runtime.GOOS {
-	case "linux":
-		// https://github.com/torvalds/linux/blob/master/include/uapi/asm-generic/fcntl.h
-		F_OFD_GETLK = 36 // F_OFD_GETLK
-	case "darwin":
-		// https://github.com/apple/darwin-xnu/blob/main/bsd/sys/fcntl.h
-		F_OFD_GETLK = 92 // F_OFD_GETLK
-	case "illumos":
-		// https://github.com/illumos/illumos-gate/blob/master/usr/src/uts/common/sys/fcntl.h
-		F_OFD_GETLK = 47 // F_OFD_GETLK
-	default:
-		return notImplErr
-	}
-	return syscall.FcntlFlock(file.Fd(), F_OFD_GETLK, lock)
-}
-
-func (vfsOSMethods) fcntlSetLock(file *os.File, lock *syscall.Flock_t) error {
-	var F_OFD_SETLK int
-	switch runtime.GOOS {
-	case "linux":
-		// https://github.com/torvalds/linux/blob/master/include/uapi/asm-generic/fcntl.h
-		F_OFD_SETLK = 37 // F_OFD_SETLK
-	case "darwin":
-		// https://github.com/apple/darwin-xnu/blob/main/bsd/sys/fcntl.h
-		F_OFD_SETLK = 90 // F_OFD_SETLK
-	case "illumos":
-		// https://github.com/illumos/illumos-gate/blob/master/usr/src/uts/common/sys/fcntl.h
-		F_OFD_SETLK = 48 // F_OFD_SETLK
-	default:
-		return notImplErr
-	}
-	return syscall.FcntlFlock(file.Fd(), F_OFD_SETLK, lock)
-}
-
-func (vfsOSMethods) lockErrorCode(err error, def xErrorCode) xErrorCode {
-	if err == nil {
-		return _OK
-	}
-	if errno, ok := err.(syscall.Errno); ok {
-		switch errno {
-		case
-			syscall.EACCES,
-			syscall.EAGAIN,
-			syscall.EBUSY,
-			syscall.EINTR,
-			syscall.ENOLCK,
-			syscall.EDEADLK,
-			syscall.ETIMEDOUT:
-			return xErrorCode(BUSY)
-		case syscall.EPERM:
-			return xErrorCode(PERM)
-		}
-	}
-	return def
-}

vfs_windows.go

@@ -1,102 +0,0 @@
-package sqlite3
-
-import (
-	"os"
-	"syscall"
-
-	"golang.org/x/sys/windows"
-)
-
-func (vfsOSMethods) DeleteOnClose(file *os.File) {}
-
-func (vfsOSMethods) GetExclusiveLock(file *os.File) xErrorCode {
-	// Release the SHARED lock.
-	vfsOS.unlock(file, _SHARED_FIRST, _SHARED_SIZE)
-
-	// Acquire the EXCLUSIVE lock.
-	rc := vfsOS.writeLock(file, _SHARED_FIRST, _SHARED_SIZE)
-
-	// Reacquire the SHARED lock.
-	if rc != _OK {
-		vfsOS.readLock(file, _SHARED_FIRST, _SHARED_SIZE)
-	}
-	return rc
-}
-
-func (vfsOSMethods) DowngradeLock(file *os.File, state vfsLockState) xErrorCode {
-	if state >= _EXCLUSIVE_LOCK {
-		// Release the SHARED lock.
-		vfsOS.unlock(file, _SHARED_FIRST, _SHARED_SIZE)
-
-		// Reacquire the SHARED lock.
-		if rc := vfsOS.readLock(file, _SHARED_FIRST, _SHARED_SIZE); rc != _OK {
-			// This should never happen.
-			// We should always be able to reacquire the read lock.
-			return IOERR_RDLOCK
-		}
-	}
-
-	// Release the PENDING and RESERVED locks.
-	if state >= _RESERVED_LOCK {
-		vfsOS.unlock(file, _RESERVED_BYTE, 1)
-	}
-	if state >= _PENDING_LOCK {
-		vfsOS.unlock(file, _PENDING_BYTE, 1)
-	}
-	return _OK
-}
-
-func (vfsOSMethods) ReleaseLock(file *os.File, state vfsLockState) xErrorCode {
-	// Release all locks.
-	if state >= _RESERVED_LOCK {
-		vfsOS.unlock(file, _RESERVED_BYTE, 1)
-	}
-	if state >= _SHARED_LOCK {
-		vfsOS.unlock(file, _SHARED_FIRST, _SHARED_SIZE)
-	}
-	if state >= _PENDING_LOCK {
-		vfsOS.unlock(file, _PENDING_BYTE, 1)
-	}
-	return _OK
-}
-
-func (vfsOSMethods) unlock(file *os.File, start, len uint32) xErrorCode {
-	err := windows.UnlockFileEx(windows.Handle(file.Fd()),
-		0, len, 0, &windows.Overlapped{Offset: start})
-	if err != nil {
-		return IOERR_UNLOCK
-	}
-	return _OK
-}
-
-func (vfsOSMethods) readLock(file *os.File, start, len uint32) xErrorCode {
-	return vfsOS.lockErrorCode(windows.LockFileEx(windows.Handle(file.Fd()),
-		windows.LOCKFILE_FAIL_IMMEDIATELY,
-		0, len, 0, &windows.Overlapped{Offset: start}),
-		IOERR_RDLOCK)
-}
-
-func (vfsOSMethods) writeLock(file *os.File, start, len uint32) xErrorCode {
-	return vfsOS.lockErrorCode(windows.LockFileEx(windows.Handle(file.Fd()),
-		windows.LOCKFILE_FAIL_IMMEDIATELY|windows.LOCKFILE_EXCLUSIVE_LOCK,
-		0, len, 0, &windows.Overlapped{Offset: start}),
-		IOERR_LOCK)
-}
-
-func (vfsOSMethods) checkLock(file *os.File, start, len uint32) (bool, xErrorCode) {
-	rc := vfsOS.readLock(file, start, len)
-	if rc == _OK {
-		vfsOS.unlock(file, start, len)
-	}
-	return rc != _OK, _OK
-}
-
-func (vfsOSMethods) lockErrorCode(err error, def xErrorCode) xErrorCode {
-	if err == nil {
-		return _OK
-	}
-	if errno, _ := err.(syscall.Errno); errno == windows.ERROR_INVALID_HANDLE {
-		return def
-	}
-	return xErrorCode(BUSY)
-}