Generate coverage chart.

Bumps [golang.org/x/sys](https://github.com/golang/sys) from 0.5.0 to 0.6.0.
- [Release notes](https://github.com/golang/sys/releases)
- [Commits](https://github.com/golang/sys/compare/v0.5.0...v0.6.0)

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

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

.github/workflows/go.yml

@@ -15,6 +15,8 @@ jobs:
 
     steps:
     - uses: actions/checkout@v3
+      with:
+        lfs: 'true'
 
     - name: Set up Go
       uses: actions/setup-go@v3
@@ -34,6 +36,8 @@ jobs:
 
     - name: Update coverage report
       uses: ncruces/go-coverage-report@main
+      with:
+        chart: '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

@@ -2,25 +2,83 @@
 
 [![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)
 
-⚠️ CAUTION ⚠️
+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.
 
-This is a WIP.\
-DO NOT USE with data you care about.
+- Package [`github.com/ncruces/go-sqlite3`](https://pkg.go.dev/github.com/ncruces/go-sqlite3)
+wraps the [C SQLite API](https://www.sqlite.org/cintro.html)
+([example usage](https://pkg.go.dev/github.com/ncruces/go-sqlite3#example-package)).
+- Package [`github.com/ncruces/go-sqlite3/driver`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/driver)
+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.
 
-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 simple, nice API, enough for simple use cases
-- [x] provide a simple `database/sql` driver
-- [x] file locking, compatible with SQLite on Windows/Unix
-- [ ] shared memory, compatible with SQLite on Windows/Unix
-  - needed for improved WAL mode
-- [ ] advanced features
-  - [ ] incremental BLOB I/O
-  - [ ] online backup
+### Caveats
+
+This module replaces the SQLite [OS Interface](https://www.sqlite.org/vfs.html) (aka VFS)
+with a pure Go implementation.
+This has numerous benefits, but also comes with some drawbacks.
+
+#### Write-Ahead Logging
+
+Because WASM does not support shared memory,
+[WAL](https://www.sqlite.org/wal.html) support is [limited](https://www.sqlite.org/wal.html#noshm).
+
+To work around this limitation, SQLite is compiled with
+[`SQLITE_DEFAULT_LOCKING_MODE=1`](https://www.sqlite.org/compile.html#default_locking_mode),
+making `EXCLUSIVE` the default locking mode.
+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.
+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
+
+On Unix, 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.
+
+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 and macOS.
+As a work around for other Unixes, you can use [`nolock=1`](https://www.sqlite.org/uri.html).
+
+#### 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
+
+- [ ] advanced SQLite features
+  - [x] nested transactions
+  - [x] incremental BLOB I/O
+  - [x] online backup
+  - [ ] snapshots
   - [ ] session extension
-  - [ ] snapshot
+  - [ ] resumable bulk update
+  - [ ] shared-cache mode
+  - [ ] unlock-notify
+- [ ] custom SQL functions
+- [ ] custom VFSes
+  - [ ] 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
+  
+### Alternatives
+
+- [`modernc.org/sqlite`](https://pkg.go.dev/modernc.org/sqlite)
+- [`crawshaw.io/sqlite`](https://pkg.go.dev/crawshaw.io/sqlite)
+- [`github.com/mattn/go-sqlite3`](https://pkg.go.dev/github.com/mattn/go-sqlite3)
+- [`github.com/zombiezen/go-sqlite`](https://pkg.go.dev/github.com/zombiezen/go-sqlite)

api.go

@@ -1,112 +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
-	}
-
-	getPtr := 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{
-			malloc:        getFun("malloc"),
-			free:          getFun("free"),
-			destructor:    uint64(getPtr("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"),
-			lastRowid:     getFun("sqlite3_last_insert_rowid"),
-			changes:       getFun("sqlite3_changes64"),
-			interrupt:     getFun("sqlite3_interrupt"),
-		},
-	}
-	if err != nil {
-		return nil, err
-	}
-	return &c, nil
-}
-
-type sqliteAPI struct {
-	malloc        api.Function
-	free          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
-	lastRowid     api.Function
-	changes       api.Function
-	interrupt     api.Function
-}

backup.go

@@ -0,0 +1,134 @@
+package sqlite3
+
+// Backup is a handle to an open BLOB.
+//
+// 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 calls [Open] to open 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 calls [Open] to open 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 calls [Open] to open 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

@@ -1,6 +1,159 @@
 package sqlite3
 
+import "io"
+
 // ZeroBlob represents a zero-filled, length n BLOB
 // that can be used as an argument to
-// [database.sql.DB.Exec] and similar methods.
+// [database/sql.DB.Exec] and similar methods.
 type ZeroBlob int64
+
+// Blob is a 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
+}
+
+var _ io.ReadWriteSeeker = &Blob{}
+
+// OpenBlob opens a BLOB for incremental I/O.
+//
+// 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)
+	tablePtr := c.arena.string(table)
+	columnPtr := c.arena.string(column)
+
+	var flags uint64
+	if write {
+		flags = 1
+	}
+
+	r := c.call(c.api.blobOpen, uint64(c.handle),
+		uint64(dbPtr), uint64(tablePtr), uint64(columnPtr),
+		uint64(row), flags, uint64(blobPtr))
+
+	if err := c.error(r[0]); err != nil {
+		return nil, err
+	}
+
+	blob := Blob{c: c}
+	blob.handle = c.mem.readUint32(blobPtr)
+	blob.bytes = int64(c.call(c.api.blobBytes, uint64(blob.handle))[0])
+	return &blob, nil
+}
+
+// Close closes a BLOB handle.
+//
+// It is safe to close a nil, zero or closed Blob.
+//
+// https://www.sqlite.org/c3ref/blob_close.html
+func (b *Blob) Close() error {
+	if b == nil || b.handle == 0 {
+		return nil
+	}
+
+	r := b.c.call(b.c.api.blobClose, uint64(b.handle))
+
+	b.handle = 0
+	return b.c.error(r[0])
+}
+
+// Size returns the size of the BLOB in bytes.
+//
+// https://www.sqlite.org/c3ref/blob_bytes.html
+func (b *Blob) Size() int64 {
+	return b.bytes
+}
+
+// Read implements the [io.Reader] interface.
+//
+// https://www.sqlite.org/c3ref/blob_read.html
+func (b *Blob) Read(p []byte) (n int, err error) {
+	if b.offset >= b.bytes {
+		return 0, io.EOF
+	}
+
+	want := int64(len(p))
+	avail := b.bytes - b.offset
+	if want > avail {
+		want = avail
+	}
+
+	ptr := b.c.new(uint64(want))
+	defer b.c.free(ptr)
+
+	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 0, err
+	}
+
+	mem := b.c.mem.view(ptr, uint64(want))
+	copy(p, mem)
+	b.offset += want
+	if b.offset >= b.bytes {
+		err = io.EOF
+	}
+	return int(want), err
+}
+
+// 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)
+
+	r := b.c.call(b.c.api.blobWrite, uint64(b.handle),
+		uint64(ptr), uint64(len(p)), uint64(offset))
+	err = b.c.error(r[0])
+	if err != nil {
+		return 0, err
+	}
+	b.offset += int64(len(p))
+	return len(p), nil
+}
+
+// Seek implements the [io.Seeker] interface.
+func (b *Blob) Seek(offset int64, whence int) (int64, error) {
+	switch whence {
+	default:
+		return 0, whenceErr
+	case io.SeekStart:
+		break
+	case io.SeekCurrent:
+		offset += b.offset
+	case io.SeekEnd:
+		offset += b.bytes
+	}
+	if offset < 0 {
+		return 0, offsetErr
+	}
+	b.offset = offset
+	return offset, nil
+}
+
+// Reopen moves a BLOB handle to a new row of the same database table.
+//
+// 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))
+	b.bytes = int64(b.c.call(b.c.api.blobBytes, uint64(b.handle))[0])
+	b.offset = 0
+	return b.c.error(r[0])
+}

compile.go

@@ -1,58 +0,0 @@
-package sqlite3
-
-import (
-	"context"
-	"os"
-	"strconv"
-	"sync"
-	"sync/atomic"
-
-	"github.com/tetratelabs/wazero"
-	"github.com/tetratelabs/wazero/api"
-)
-
-// Configure SQLite.
-var (
-	Binary []byte // 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))
-	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

@@ -2,64 +2,118 @@ package sqlite3
 
 import (
 	"context"
-	"math"
+	"database/sql/driver"
+	"errors"
+	"fmt"
+	"net/url"
+	"runtime"
+	"strings"
+	"sync/atomic"
+	"unsafe"
 )
 
 // Conn is a database connection handle.
+// A Conn is not safe for concurrent use by multiple goroutines.
 //
 // https://www.sqlite.org/c3ref/sqlite3.html
 type Conn struct {
-	ctx    context.Context
-	api    sqliteAPI
-	mem    memory
-	handle uint32
+	*module
 
-	arena   arena
-	pending *Stmt
-	waiter  chan struct{}
-	done    <-chan struct{}
+	handle    uint32
+	arena     arena
+	interrupt context.Context
+	waiter    chan struct{}
+	pending   *Stmt
 }
 
-// Open calls [OpenFlags] with [OPEN_READWRITE] and [OPEN_CREATE].
-func Open(filename string) (conn *Conn, err error) {
-	return OpenFlags(filename, OPEN_READWRITE|OPEN_CREATE)
+// 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, 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)
 
-	r, err := c.api.open.Call(c.ctx, uint64(namePtr), uint64(connPtr), uint64(flags), 0)
-	if err != nil {
-		panic(err)
+	flags |= OPEN_EXRESCODE
+	r := c.call(c.api.open, uint64(namePtr), uint64(connPtr), uint64(flags), 0)
+
+	handle := c.mem.readUint32(connPtr)
+	if err := c.module.error(r[0], handle); err != nil {
+		c.closeDB(handle)
+		return 0, err
 	}
 
-	c.handle = c.mem.readUint32(connPtr)
-	if err := c.error(r[0]); err != nil {
-		return nil, err
+	if flags|OPEN_URI != 0 && strings.HasPrefix(filename, "file:") {
+		var pragmas strings.Builder
+		if _, after, ok := strings.Cut(filename, "?"); ok {
+			query, _ := url.ParseQuery(after)
+			for _, p := range query["_pragma"] {
+				pragmas.WriteString(`PRAGMA `)
+				pragmas.WriteString(p)
+				pragmas.WriteByte(';')
+			}
+		}
+
+		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
+		}
+	}
+
+	c.call(c.api.timeCollation, uint64(handle))
+	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)
 	}
-	return c, nil
 }
 
 // Close closes the database connection.
@@ -68,7 +122,7 @@ func OpenFlags(filename string, flags OpenFlag) (conn *Conn, err error) {
 // open blob handles, and/or unfinished backup objects,
 // Close will leave the database connection open and return [BUSY].
 //
-// It is safe to close a nil, zero or closed connection.
+// It is safe to close a nil, zero or closed Conn.
 //
 // https://www.sqlite.org/c3ref/close.html
 func (c *Conn) Close() error {
@@ -76,82 +130,18 @@ func (c *Conn) Close() error {
 		return nil
 	}
 
-	c.SetInterrupt(nil)
-
-	r, err := c.api.close.Call(c.ctx, uint64(c.handle))
-	if err != nil {
-		panic(err)
-	}
+	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 {
 		return err
 	}
 
 	c.handle = 0
-	return c.mem.mod.Close(c.ctx)
-}
-
-// SetInterrupt interrupts a long-running query when done is closed.
-//
-// Subsequent uses of the connection will return [INTERRUPT]
-// until done is reset by another call to SetInterrupt.
-//
-// Typically, done is provided by [context.Context.Done]:
-//
-//	ctx, cancel := context.WithTimeout(context.TODO(), 100*time.Millisecond)
-//	conn.SetInterrupt(ctx.Done())
-//	defer cancel()
-//
-// https://www.sqlite.org/c3ref/interrupt.html
-func (c *Conn) SetInterrupt(done <-chan struct{}) (old <-chan struct{}) {
-	// Is a waiter running?
-	if c.waiter != nil {
-		c.waiter <- struct{}{} // Cancel the waiter.
-		<-c.waiter             // Wait for it to finish.
-		c.waiter = nil
-	}
-
-	// Finalize the uncompleted SQL statement.
-	if c.pending != nil {
-		c.pending.Close()
-		c.pending = nil
-	}
-
-	old = c.done
-	c.done = done
-	if done == nil {
-		return old
-	}
-
-	// Creating an uncompleted SQL statement prevents SQLite from ignoring
-	// an interrupt that comes before any other statements are started.
-	c.pending, _, _ = c.Prepare(`SELECT 1 UNION ALL SELECT 2`)
-	c.pending.Step()
-
-	waiter := make(chan struct{})
-	c.waiter = waiter
-	go func() {
-		select {
-		case <-waiter: // Waiter was cancelled.
-			break
-
-		case <-done: // Done was closed.
-
-			// This is safe to call from a goroutine
-			// because it doesn't touch the C stack.
-			_, err := c.api.interrupt.Call(c.ctx, uint64(c.handle))
-			if err != nil {
-				panic(err)
-			}
-
-			// Wait for the next call to SetInterrupt.
-			<-waiter
-		}
-
-		// Signal that the waiter has finished.
-		waiter <- struct{}{}
-	}()
-	return old
+	runtime.SetFinalizer(c, nil)
+	return c.module.close()
 }
 
 // Exec is a convenience function that allows an application to run
@@ -159,13 +149,11 @@ func (c *Conn) SetInterrupt(done <-chan struct{}) (old <-chan struct{}) {
 //
 // https://www.sqlite.org/c3ref/exec.html
 func (c *Conn) Exec(sql string) error {
+	c.checkInterrupt()
 	defer c.arena.reset()
 	sqlPtr := c.arena.string(sql)
 
-	r, err := c.api.exec.Call(c.ctx, uint64(c.handle), uint64(sqlPtr), 0, 0, 0)
-	if err != nil {
-		panic(err)
-	}
+	r := c.call(c.api.exec, uint64(c.handle), uint64(sqlPtr), 0, 0, 0)
 	return c.error(r[0])
 }
 
@@ -190,12 +178,9 @@ func (c *Conn) PrepareFlags(sql string, flags PrepareFlag) (stmt *Stmt, tail str
 	tailPtr := c.arena.new(ptrlen)
 	sqlPtr := c.arena.string(sql)
 
-	r, err := c.api.prepare.Call(c.ctx, uint64(c.handle),
+	r := c.call(c.api.prepare, uint64(c.handle),
 		uint64(sqlPtr), uint64(len(sql)+1), uint64(flags),
 		uint64(stmtPtr), uint64(tailPtr))
-	if err != nil {
-		panic(err)
-	}
 
 	stmt = &Stmt{c: c}
 	stmt.handle = c.mem.readUint32(stmtPtr)
@@ -211,16 +196,21 @@ func (c *Conn) PrepareFlags(sql string, flags PrepareFlag) (stmt *Stmt, tail str
 	return
 }
 
+// GetAutocommit tests the connection for auto-commit mode.
+//
+// https://www.sqlite.org/c3ref/get_autocommit.html
+func (c *Conn) GetAutocommit() bool {
+	r := c.call(c.api.autocommit, uint64(c.handle))
+	return r[0] != 0
+}
+
 // LastInsertRowID returns the rowid of the most recent successful INSERT
 // on the database connection.
 //
 // https://www.sqlite.org/c3ref/last_insert_rowid.html
-func (c *Conn) LastInsertRowID() uint64 {
-	r, err := c.api.lastRowid.Call(c.ctx, uint64(c.handle))
-	if err != nil {
-		panic(err)
-	}
-	return r[0]
+func (c *Conn) LastInsertRowID() int64 {
+	r := c.call(c.api.lastRowid, uint64(c.handle))
+	return int64(r[0])
 }
 
 // Changes returns the number of rows modified, inserted or deleted
@@ -228,125 +218,118 @@ func (c *Conn) LastInsertRowID() uint64 {
 // on the database connection.
 //
 // https://www.sqlite.org/c3ref/changes.html
-func (c *Conn) Changes() uint64 {
-	r, err := c.api.changes.Call(c.ctx, uint64(c.handle))
-	if err != nil {
-		panic(err)
+func (c *Conn) Changes() int64 {
+	r := c.call(c.api.changes, uint64(c.handle))
+	return int64(r[0])
+}
+
+// SetInterrupt interrupts a long-running query when a context is done.
+//
+// Subsequent uses of the connection will return [INTERRUPT]
+// until the context is reset by another call to SetInterrupt.
+//
+// To associate a timeout with a connection:
+//
+//	ctx, cancel := context.WithTimeout(context.TODO(), 100*time.Millisecond)
+//	conn.SetInterrupt(ctx)
+//	defer cancel()
+//
+// SetInterrupt returns the old context assigned to the connection.
+//
+// https://www.sqlite.org/c3ref/interrupt.html
+func (c *Conn) SetInterrupt(ctx context.Context) (old context.Context) {
+	// Is a waiter running?
+	if c.waiter != nil {
+		c.waiter <- struct{}{} // Cancel the waiter.
+		<-c.waiter             // Wait for it to finish.
+		c.waiter = nil
 	}
-	return r[0]
+	// Reset the pending statement.
+	if c.pending != nil {
+		c.pending.Reset()
+	}
+
+	old = c.interrupt
+	c.interrupt = ctx
+	if ctx == nil || ctx.Done() == 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.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.
+	if c.checkInterrupt() {
+		return old
+	}
+
+	waiter := make(chan struct{})
+	c.waiter = waiter
+	go func() {
+		select {
+		case <-waiter: // Waiter was cancelled.
+			break
+
+		case <-ctx.Done(): // Done was closed.
+			buf := c.mem.view(c.handle+c.api.interrupt, 4)
+			(*atomic.Uint32)(unsafe.Pointer(&buf[0])).Store(1)
+			// Wait for the next call to SetInterrupt.
+			<-waiter
+		}
+
+		// Signal that the waiter has finished.
+		waiter <- struct{}{}
+	}()
+	return old
+}
+
+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)
+	(*atomic.Uint32)(unsafe.Pointer(&buf[0])).Store(1)
+	return true
+}
+
+// Pragma executes a PRAGMA statement and returns any results.
+//
+// https://www.sqlite.org/pragma.html
+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, 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
+	return c.module.error(rc, c.handle, sql...)
 }
 
-func (c *Conn) free(ptr uint32) {
-	if ptr == 0 {
-		return
-	}
-	_, err := c.api.free.Call(c.ctx, uint64(ptr))
-	if err != nil {
-		panic(err)
-	}
-}
+// DriverConn is implemented by the SQLite [database/sql] driver connection.
+//
+// It can be used to access advanced SQLite features like
+// [savepoints] and [incremental BLOB I/O].
+//
+// [savepoints]: https://www.sqlite.org/lang_savepoint.html
+// [incremental BLOB I/O]: https://www.sqlite.org/c3ref/blob_open.html
+type DriverConn interface {
+	driver.ConnBeginTx
+	driver.ExecerContext
+	driver.ConnPrepareContext
 
-func (c *Conn) new(size uint32) uint32 {
-	r, err := c.api.malloc.Call(c.ctx, uint64(size))
-	if err != nil {
-		panic(err)
-	}
-	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(uint32(len(b)))
-	c.mem.writeBytes(ptr, b)
-	return ptr
-}
-
-func (c *Conn) newString(s string) uint32 {
-	ptr := c.new(uint32(len(s) + 1))
-	c.mem.writeString(ptr, s)
-	return ptr
-}
-
-func (c *Conn) newArena(size uint32) arena {
-	return arena{
-		c:    c,
-		size: size,
-		base: c.new(size),
-	}
-}
-
-type arena struct {
-	c    *Conn
-	base uint32
-	next uint32
-	size uint32
-	ptrs []uint32
-}
-
-func (a *arena) reset() {
-	for _, ptr := range a.ptrs {
-		a.c.free(ptr)
-	}
-	a.ptrs = nil
-	a.next = 0
-}
-
-func (a *arena) new(size uint32) uint32 {
-	if a.next+size <= a.size {
-		ptr := a.base + a.next
-		a.next += 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(uint32(len(s) + 1))
-	a.c.mem.writeString(ptr, s)
-	return ptr
+	Savepoint() Savepoint
+	OpenBlob(db, table, column string, row int64, write bool) (*Blob, error)
 }

const.go

@@ -7,11 +7,15 @@ const (
 	_ROW  = 100 /* sqlite3_step() has another row ready */
 	_DONE = 101 /* sqlite3_step() has finished executing */
 
+	_OK_SYMLINK = (_OK | (2 << 8)) /* internal use only */
+
 	_UTF8 = 1
 
 	_MAX_STRING   = 512 // Used for short strings: names, error messages…
 	_MAX_PATHNAME = 512
 
+	_MAX_ALLOCATION_SIZE = 0x7ffffeff
+
 	ptrlen = 4
 )
 
@@ -131,6 +135,7 @@ 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)
 )
@@ -165,14 +170,6 @@ const (
 	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 */
-)
-
 // PrepareFlag is a flag that can be passed to [Conn.PrepareFlags].
 //
 // https://www.sqlite.org/c3ref/c_prepare_normalize.html
@@ -214,3 +211,65 @@ func (t Datatype) String() string {
 	}
 	return strconv.FormatUint(uint64(t), 10)
 }
+
+type _AccessFlag uint32
+
+const (
+	_ACCESS_EXISTS    _AccessFlag = 0
+	_ACCESS_READWRITE _AccessFlag = 1 /* Used by PRAGMA temp_store_directory */
+	_ACCESS_READ      _AccessFlag = 2 /* Unused */
+)
+
+type _SyncFlag uint32
+
+const (
+	_SYNC_NORMAL   _SyncFlag = 0x00002
+	_SYNC_FULL     _SyncFlag = 0x00003
+	_SYNC_DATAONLY _SyncFlag = 0x00010
+)
+
+type _FcntlOpcode uint32
+
+const (
+	_FCNTL_LOCKSTATE             = 1
+	_FCNTL_GET_LOCKPROXYFILE     = 2
+	_FCNTL_SET_LOCKPROXYFILE     = 3
+	_FCNTL_LAST_ERRNO            = 4
+	_FCNTL_SIZE_HINT             = 5
+	_FCNTL_CHUNK_SIZE            = 6
+	_FCNTL_FILE_POINTER          = 7
+	_FCNTL_SYNC_OMITTED          = 8
+	_FCNTL_WIN32_AV_RETRY        = 9
+	_FCNTL_PERSIST_WAL           = 10
+	_FCNTL_OVERWRITE             = 11
+	_FCNTL_VFSNAME               = 12
+	_FCNTL_POWERSAFE_OVERWRITE   = 13
+	_FCNTL_PRAGMA                = 14
+	_FCNTL_BUSYHANDLER           = 15
+	_FCNTL_TEMPFILENAME          = 16
+	_FCNTL_MMAP_SIZE             = 18
+	_FCNTL_TRACE                 = 19
+	_FCNTL_HAS_MOVED             = 20
+	_FCNTL_SYNC                  = 21
+	_FCNTL_COMMIT_PHASETWO       = 22
+	_FCNTL_WIN32_SET_HANDLE      = 23
+	_FCNTL_WAL_BLOCK             = 24
+	_FCNTL_ZIPVFS                = 25
+	_FCNTL_RBU                   = 26
+	_FCNTL_VFS_POINTER           = 27
+	_FCNTL_JOURNAL_POINTER       = 28
+	_FCNTL_WIN32_GET_HANDLE      = 29
+	_FCNTL_PDB                   = 30
+	_FCNTL_BEGIN_ATOMIC_WRITE    = 31
+	_FCNTL_COMMIT_ATOMIC_WRITE   = 32
+	_FCNTL_ROLLBACK_ATOMIC_WRITE = 33
+	_FCNTL_LOCK_TIMEOUT          = 34
+	_FCNTL_DATA_VERSION          = 35
+	_FCNTL_SIZE_LIMIT            = 36
+	_FCNTL_CKPT_DONE             = 37
+	_FCNTL_RESERVE_BYTES         = 38
+	_FCNTL_CKPT_START            = 39
+	_FCNTL_EXTERNAL_READER       = 40
+	_FCNTL_CKSM_FILE             = 41
+	_FCNTL_RESET_CACHE           = 42
+)

driver/driver.go

@@ -1,4 +1,27 @@
 // Package driver provides a database/sql driver for SQLite.
+//
+// Importing package driver registers a [database/sql] driver named "sqlite3".
+// You may also need to import package embed.
+//
+//	import _ "github.com/ncruces/go-sqlite3/driver"
+//	import _ "github.com/ncruces/go-sqlite3/embed"
+//
+// The data source name for "sqlite3" databases can be a filename or a "file:" [URI].
+//
+// The [TRANSACTION] mode can be specified using "_txlock":
+//
+//	sql.Open("sqlite3", "file:demo.db?_txlock=immediate")
+//
+// [PRAGMA] statements can be specified using "_pragma":
+//
+//	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
+// and normal locking mode are used.
+//
+// [URI]: https://www.sqlite.org/uri.html
+// [PRAGMA]: https://www.sqlite.org/pragma.html
+// [TRANSACTION]: https://www.sqlite.org/lang_transaction.html#deferred_immediate_and_exclusive_transactions
 package driver
 
 import (
@@ -20,102 +43,112 @@ func init() {
 
 type sqlite struct{}
 
-func (sqlite) Open(name string) (driver.Conn, error) {
-	c, err := sqlite3.OpenFlags(name, sqlite3.OPEN_READWRITE|sqlite3.OPEN_CREATE|sqlite3.OPEN_URI|sqlite3.OPEN_EXRESCODE)
+func (sqlite) Open(name string) (_ driver.Conn, err error) {
+	c, err := sqlite3.Open(name)
 	if err != nil {
 		return nil, err
 	}
 
 	var txBegin string
-	var pragmas strings.Builder
-	if _, after, ok := strings.Cut(name, "?"); ok {
-		query, _ := url.ParseQuery(after)
+	var pragmas []string
+	if strings.HasPrefix(name, "file:") {
+		if _, after, ok := strings.Cut(name, "?"); ok {
+			query, _ := url.ParseQuery(after)
 
-		switch s := query.Get("_txlock"); s {
-		case "":
-			txBegin = "BEGIN"
-		case "deferred", "immediate", "exclusive":
-			txBegin = "BEGIN " + s
-		default:
-			return nil, fmt.Errorf("sqlite3: invalid _txlock: %s", s)
-		}
+			switch s := query.Get("_txlock"); s {
+			case "":
+				txBegin = "BEGIN"
+			case "deferred", "immediate", "exclusive":
+				txBegin = "BEGIN " + s
+			default:
+				c.Close()
+				return nil, fmt.Errorf("sqlite3: invalid _txlock: %s", s)
+			}
 
-		for _, p := range query["_pragma"] {
-			pragmas.WriteString(`PRAGMA `)
-			pragmas.WriteString(p)
-			pragmas.WriteByte(';')
+			pragmas = query["_pragma"]
 		}
 	}
-	if pragmas.Len() == 0 {
-		pragmas.WriteString(`PRAGMA locking_mode=normal;`)
-		pragmas.WriteString(`PRAGMA busy_timeout=60000;`)
+	if len(pragmas) == 0 {
+		err := c.Exec(`
+			PRAGMA busy_timeout=60000;
+			PRAGMA locking_mode=normal;
+		`)
+		if err != nil {
+			c.Close()
+			return nil, err
+		}
 	}
 
-	err = c.Exec(pragmas.String())
-	if err != nil {
-		return nil, fmt.Errorf("sqlite3: invalid _pragma: %w", err)
-	}
 	return conn{
 		conn:    c,
 		txBegin: txBegin,
-		pragmas: pragmas.String(),
 	}, nil
 }
 
 type conn struct {
 	conn       *sqlite3.Conn
-	pragmas    string
 	txBegin    string
-	txReadOnly bool
+	txCommit   string
+	txRollback string
 }
 
 var (
 	// Ensure these interfaces are implemented:
-	_ driver.Validator       = conn{}
-	_ driver.SessionResetter = conn{}
-	_ driver.ExecerContext   = conn{}
-	_ driver.ConnBeginTx     = conn{}
+	_ driver.ExecerContext = conn{}
+	_ driver.ConnBeginTx   = conn{}
+	_ driver.Validator     = conn{}
+	_ sqlite3.DriverConn   = conn{}
 )
 
 func (c conn) Close() error {
 	return c.conn.Close()
 }
 
-func (c conn) IsValid() bool {
-	// Pool only normal locking mode connections.
-	stmt, _, err := c.conn.Prepare(`PRAGMA locking_mode`)
-	if err != nil {
-		return false
-	}
-	defer stmt.Close()
-	return stmt.Step() && stmt.ColumnText(0) == "normal"
-}
-
-func (c conn) ResetSession(ctx context.Context) error {
-	return c.conn.Exec(c.pragmas)
+func (c conn) IsValid() (valid bool) {
+	r, err := c.conn.Pragma("locking_mode")
+	return err == nil && len(r) == 1 && r[0] == "normal"
 }
 
 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) {
+func (c conn) BeginTx(_ context.Context, opts driver.TxOptions) (driver.Tx, error) {
+	txBegin := c.txBegin
+	c.txCommit = `COMMIT`
+	c.txRollback = `ROLLBACK`
+
+	if opts.ReadOnly {
+		query_only, err := c.conn.Pragma("query_only")
+		if err != nil {
+			return nil, err
+		}
+		txBegin = `
+			BEGIN deferred;
+			PRAGMA query_only=on`
+		c.txCommit = `
+			ROLLBACK;
+			PRAGMA query_only=` + query_only[0]
+		c.txRollback = c.txCommit
+	}
+
 	switch opts.Isolation {
 	default:
 		return nil, isolationErr
-	case driver.IsolationLevel(sql.LevelDefault):
-	case driver.IsolationLevel(sql.LevelSerializable):
+	case
+		driver.IsolationLevel(sql.LevelDefault),
+		driver.IsolationLevel(sql.LevelSerializable):
+		break
+	case driver.IsolationLevel(sql.LevelReadUncommitted):
+		read_uncommitted, err := c.conn.Pragma("read_uncommitted")
+		if err != nil {
+			return nil, err
+		}
+		txBegin += `; PRAGMA read_uncommitted=on`
+		c.txCommit += `; PRAGMA read_uncommitted=` + read_uncommitted[0]
+		c.txRollback += `; PRAGMA read_uncommitted=` + read_uncommitted[0]
 	}
 
-	txBegin := c.txBegin
-	if opts.ReadOnly {
-		txBegin = `
-			BEGIN deferred;
-			PRAGMA query_only=on;
-		`
-	}
-	c.txReadOnly = opts.ReadOnly
-
 	err := c.conn.Exec(txBegin)
 	if err != nil {
 		return nil, err
@@ -124,18 +157,15 @@ func (c conn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, er
 }
 
 func (c conn) Commit() error {
-	if c.txReadOnly {
-		return c.Rollback()
-	}
-	err := c.conn.Exec(`COMMIT`)
-	if err != nil {
+	err := c.conn.Exec(c.txCommit)
+	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) {
@@ -159,14 +189,18 @@ func (c conn) Prepare(query string) (driver.Stmt, error) {
 	return stmt{s, c.conn}, nil
 }
 
+func (c conn) PrepareContext(_ context.Context, query string) (driver.Stmt, error) {
+	return c.Prepare(query)
+}
+
 func (c conn) ExecContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Result, error) {
 	if len(args) != 0 {
 		// Slow path.
 		return nil, driver.ErrSkip
 	}
 
-	ch := c.conn.SetInterrupt(ctx.Done())
-	defer c.conn.SetInterrupt(ch)
+	old := c.conn.SetInterrupt(ctx)
+	defer c.conn.SetInterrupt(old)
 
 	err := c.conn.Exec(query)
 	if err != nil {
@@ -174,11 +208,19 @@ func (c conn) ExecContext(ctx context.Context, query string, args []driver.Named
 	}
 
 	return result{
-		int64(c.conn.LastInsertRowID()),
-		int64(c.conn.Changes()),
+		c.conn.LastInsertRowID(),
+		c.conn.Changes(),
 	}, nil
 }
 
+func (c conn) Savepoint() sqlite3.Savepoint {
+	return c.conn.Savepoint()
+}
+
+func (c conn) OpenBlob(db, table, column string, row int64, write bool) (*sqlite3.Blob, error) {
+	return c.conn.OpenBlob(db, table, column, row, write)
+}
+
 type stmt struct {
 	stmt *sqlite3.Stmt
 	conn *sqlite3.Conn
@@ -325,8 +367,8 @@ func (r rows) Columns() []string {
 }
 
 func (r rows) Next(dest []driver.Value) error {
-	ch := r.conn.SetInterrupt(r.ctx.Done())
-	defer r.conn.SetInterrupt(ch)
+	old := r.conn.SetInterrupt(r.ctx)
+	defer r.conn.SetInterrupt(old)
 
 	if !r.stmt.Step() {
 		if err := r.stmt.Err(); err != nil {
@@ -342,7 +384,7 @@ func (r rows) Next(dest []driver.Value) error {
 		case sqlite3.FLOAT:
 			dest[i] = r.stmt.ColumnFloat(i)
 		case sqlite3.TEXT:
-			dest[i] = maybeDate(r.stmt.ColumnText(i))
+			dest[i] = maybeTime(r.stmt.ColumnText(i))
 		case sqlite3.BLOB:
 			buf, _ := dest[i].([]byte)
 			dest[i] = r.stmt.ColumnBlob(i, buf)

driver/driver_test.go

@@ -1,4 +1,3 @@
-// Package driver provides a database/sql driver for SQLite.
 package driver
 
 import (
@@ -15,6 +14,8 @@ import (
 )
 
 func Test_Open_dir(t *testing.T) {
+	t.Parallel()
+
 	db, err := sql.Open("sqlite3", ".")
 	if err != nil {
 		t.Fatal(err)
@@ -25,19 +26,14 @@ func Test_Open_dir(t *testing.T) {
 	if err == nil {
 		t.Fatal("want error")
 	}
-	var serr *sqlite3.Error
-	if !errors.As(err, &serr) {
-		t.Fatalf("got %T, want sqlite3.Error", err)
-	}
-	if rc := serr.Code(); rc != sqlite3.CANTOPEN {
-		t.Errorf("got %d, want sqlite3.CANTOPEN", rc)
-	}
-	if got := err.Error(); got != `sqlite3: unable to open database file` {
-		t.Error("got message: ", got)
+	if !errors.Is(err, sqlite3.CANTOPEN) {
+		t.Errorf("got %v, want sqlite3.CANTOPEN", err)
 	}
 }
 
 func Test_Open_pragma(t *testing.T) {
+	t.Parallel()
+
 	db, err := sql.Open("sqlite3", "file::memory:?_pragma=busy_timeout(1000)")
 	if err != nil {
 		t.Fatal(err)
@@ -55,6 +51,8 @@ func Test_Open_pragma(t *testing.T) {
 }
 
 func Test_Open_pragma_invalid(t *testing.T) {
+	t.Parallel()
+
 	db, err := sql.Open("sqlite3", "file::memory:?_pragma=busy_timeout+1000")
 	if err != nil {
 		t.Fatal(err)
@@ -73,13 +71,15 @@ func Test_Open_pragma_invalid(t *testing.T) {
 		t.Errorf("got %d, want sqlite3.ERROR", rc)
 	}
 	if got := err.Error(); got != `sqlite3: invalid _pragma: sqlite3: SQL logic error: near "1000": syntax error` {
-		t.Error("got message: ", got)
+		t.Error("got message:", got)
 	}
 }
 
 func Test_Open_txLock(t *testing.T) {
+	t.Parallel()
+
 	db, err := sql.Open("sqlite3", "file:"+
-		filepath.Join(t.TempDir(), "test.db")+
+		filepath.ToSlash(filepath.Join(t.TempDir(), "test.db"))+
 		"?_txlock=exclusive&_pragma=busy_timeout(0)")
 	if err != nil {
 		t.Fatal(err)
@@ -95,20 +95,13 @@ func Test_Open_txLock(t *testing.T) {
 	if err == nil {
 		t.Error("want error")
 	}
-	var serr *sqlite3.Error
-	if !errors.As(err, &serr) {
-		t.Fatalf("got %T, want sqlite3.Error", err)
-	}
-	if rc := serr.Code(); rc != sqlite3.BUSY {
-		t.Errorf("got %d, want sqlite3.BUSY", rc)
+	if !errors.Is(err, sqlite3.BUSY) {
+		t.Errorf("got %v, want sqlite3.BUSY", err)
 	}
 	var terr interface{ Temporary() bool }
 	if !errors.As(err, &terr) || !terr.Temporary() {
 		t.Error("not temporary", err)
 	}
-	if got := err.Error(); got != `sqlite3: database is locked` {
-		t.Error("got message: ", got)
-	}
 
 	err = tx1.Commit()
 	if err != nil {
@@ -117,6 +110,8 @@ func Test_Open_txLock(t *testing.T) {
 }
 
 func Test_Open_txLock_invalid(t *testing.T) {
+	t.Parallel()
+
 	db, err := sql.Open("sqlite3", "file::memory:?_txlock=xclusive")
 	if err != nil {
 		t.Fatal(err)
@@ -128,15 +123,19 @@ func Test_Open_txLock_invalid(t *testing.T) {
 		t.Fatal("want error")
 	}
 	if got := err.Error(); got != `sqlite3: invalid _txlock: xclusive` {
-		t.Error("got message: ", got)
+		t.Error("got message:", got)
 	}
 }
 
 func Test_BeginTx(t *testing.T) {
+	t.Parallel()
+
 	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)
 	}
@@ -147,6 +146,16 @@ func Test_BeginTx(t *testing.T) {
 		t.Error("want isolationErr")
 	}
 
+	tx, err := db.BeginTx(ctx, &sql.TxOptions{Isolation: sql.LevelReadUncommitted})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = tx.Rollback()
+	if err != nil {
+		t.Fatal(err)
+	}
+
 	tx1, err := db.BeginTx(ctx, &sql.TxOptions{ReadOnly: true})
 	if err != nil {
 		t.Fatal(err)
@@ -161,15 +170,8 @@ func Test_BeginTx(t *testing.T) {
 	if err == nil {
 		t.Error("want error")
 	}
-	var serr *sqlite3.Error
-	if !errors.As(err, &serr) {
-		t.Fatalf("got %T, want sqlite3.Error", err)
-	}
-	if rc := serr.Code(); rc != sqlite3.READONLY {
-		t.Errorf("got %d, want sqlite3.READONLY", rc)
-	}
-	if got := err.Error(); got != `sqlite3: attempt to write a readonly database` {
-		t.Error("got message: ", got)
+	if !errors.Is(err, sqlite3.READONLY) {
+		t.Errorf("got %v, want sqlite3.READONLY", err)
 	}
 
 	err = tx2.Commit()
@@ -184,6 +186,8 @@ func Test_BeginTx(t *testing.T) {
 }
 
 func Test_Prepare(t *testing.T) {
+	t.Parallel()
+
 	db, err := sql.Open("sqlite3", ":memory:")
 	if err != nil {
 		t.Fatal(err)
@@ -208,7 +212,7 @@ func Test_Prepare(t *testing.T) {
 		t.Errorf("got %d, want sqlite3.ERROR", rc)
 	}
 	if got := err.Error(); got != `sqlite3: SQL logic error: incomplete input` {
-		t.Error("got message: ", got)
+		t.Error("got message:", got)
 	}
 
 	_, err = db.Prepare(`SELECT 1; SELECT`)
@@ -222,7 +226,7 @@ func Test_Prepare(t *testing.T) {
 		t.Errorf("got %d, want sqlite3.ERROR", rc)
 	}
 	if got := err.Error(); got != `sqlite3: SQL logic error: incomplete input` {
-		t.Error("got message: ", got)
+		t.Error("got message:", got)
 	}
 
 	_, err = db.Prepare(`SELECT 1; SELECT 2`)
@@ -232,6 +236,8 @@ func Test_Prepare(t *testing.T) {
 }
 
 func Test_QueryRow_named(t *testing.T) {
+	t.Parallel()
+
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
@@ -282,6 +288,8 @@ func Test_QueryRow_named(t *testing.T) {
 }
 
 func Test_QueryRow_blob_null(t *testing.T) {
+	t.Parallel()
+
 	db, err := sql.Open("sqlite3", ":memory:")
 	if err != nil {
 		t.Fatal(err)
@@ -310,39 +318,3 @@ func Test_QueryRow_blob_null(t *testing.T) {
 		}
 	}
 }
-
-func Test_ZeroBlob(t *testing.T) {
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	db, err := sql.Open("sqlite3", ":memory:")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer db.Close()
-
-	conn, err := db.Conn(ctx)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer conn.Close()
-
-	_, err = conn.ExecContext(ctx, `CREATE TABLE IF NOT EXISTS test (col)`)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	_, err = conn.ExecContext(ctx, `INSERT INTO test(col) VALUES(?)`, sqlite3.ZeroBlob(4))
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	var got []byte
-	err = conn.QueryRowContext(ctx, `SELECT col FROM test`).Scan(&got)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if string(got) != "\x00\x00\x00\x00" {
-		t.Errorf(`got %q, want "\x00\x00\x00\x00"`, got)
-	}
-}

driver/example_test.go

@@ -28,10 +28,11 @@ func Example() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	defer db.Close()
 	defer os.Remove("./recordings.db")
+	defer db.Close()
 
-	err = createAlbumsTable()
+	// Create a table with some data in it.
+	err = albumsSetup()
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -58,14 +59,13 @@ func Example() {
 		log.Fatal(err)
 	}
 	fmt.Printf("ID of added album: %v\n", albID)
-
 	// Output:
 	// Albums found: [{1 Blue Train John Coltrane 56.99} {2 Giant Steps John Coltrane 63.99}]
 	// Album found: {2 Giant Steps John Coltrane 63.99}
 	// ID of added album: 5
 }
 
-func createAlbumsTable() error {
+func albumsSetup() error {
 	_, err := db.Exec(`
 		DROP TABLE IF EXISTS album;
 		CREATE TABLE album (

driver/time.go

@@ -8,8 +8,8 @@ import (
 // Convert a string in [time.RFC3339Nano] format into a [time.Time]
 // 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 maybeDate(text string) driver.Value {
+// but if a string is needed, [database/sql] will recover the same string.
+func maybeTime(text string) driver.Value {
 	// Weed out (some) values that can't possibly be
 	// [time.RFC3339Nano] timestamps.
 	if len(text) < len("2006-01-02T15:04:05Z") {

driver/time_test.go

@@ -5,7 +5,8 @@ import (
 	"time"
 )
 
-func Fuzz_maybeDate(f *testing.F) {
+// This checks that any string can be recovered as the same string.
+func Fuzz_maybeTime_1(f *testing.F) {
 	f.Add("")
 	f.Add(" ")
 	f.Add("SQLite")
@@ -21,7 +22,7 @@ func Fuzz_maybeDate(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 := maybeDate(str)
+		value := maybeTime(str)
 
 		switch v := value.(type) {
 		case time.Time:
@@ -44,3 +45,56 @@ func Fuzz_maybeDate(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) {
+	f.Add(0, 0)
+	f.Add(0, 1)
+	f.Add(0, -1)
+	f.Add(0, 999_999_999)
+	f.Add(0, 1_000_000_000)
+	f.Add(7956915742, 222_222_222)    // twosday
+	f.Add(639095955742, 222_222_222)  // twosday, year 22222AD
+	f.Add(-763421161058, 222_222_222) // twosday, year 22222BC
+
+	checkTime := func(t *testing.T, date time.Time) {
+		value := maybeTime(date.Format(time.RFC3339Nano))
+
+		switch v := value.(type) {
+		case time.Time:
+			// Make sure times round-trip to the same time:
+			if !v.Equal(date) {
+				t.Fatalf("did not round-trip: %v", date)
+			}
+			// Make with the same zone offset:
+			_, off1 := v.Zone()
+			_, off2 := date.Zone()
+			if off1 != off2 {
+				t.Fatalf("did not round-trip: %v", date)
+			}
+		case string:
+			t.Fatalf("was not recovered: %v", date)
+		default:
+			t.Fatalf("invalid type %T: %v", v, date)
+		}
+	}
+
+	f.Fuzz(func(t *testing.T, sec, nsec int) {
+		// Reduce the search space.
+		if 1e12 < sec || sec < -1e12 {
+			// Dates before 29000BC and after 33000AD; I think we're safe.
+			return
+		}
+		if 0 < nsec || nsec > 1e10 {
+			// Out of range nsec: [time.Time.Unix] handles these.
+			return
+		}
+
+		unix := time.Unix(int64(sec), int64(nsec))
+		checkTime(t, unix)
+		checkTime(t, unix.UTC())
+		checkTime(t, unix.In(time.FixedZone("", -8*3600)))
+		checkTime(t, unix.In(time.FixedZone("", +8*3600)))
+	})
+}

driver_test.go

@@ -0,0 +1,75 @@
+package sqlite3_test
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"log"
+	"os"
+
+	"github.com/ncruces/go-sqlite3"
+	_ "github.com/ncruces/go-sqlite3/driver"
+	_ "github.com/ncruces/go-sqlite3/embed"
+)
+
+var db *sql.DB
+
+func ExampleDriverConn() {
+	var err error
+	db, err = sql.Open("sqlite3", "demo.db")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer os.Remove("demo.db")
+	defer db.Close()
+
+	ctx := context.Background()
+
+	conn, err := db.Conn(ctx)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer conn.Close()
+
+	_, err = conn.ExecContext(ctx, `CREATE TABLE IF NOT EXISTS test (col)`)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	res, err := conn.ExecContext(ctx, `INSERT INTO test VALUES (?)`, sqlite3.ZeroBlob(11))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	id, err := res.LastInsertId()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	err = conn.Raw(func(driverConn any) error {
+		conn := driverConn.(sqlite3.DriverConn)
+		savept := conn.Savepoint()
+		defer savept.Release(&err)
+
+		blob, err := conn.OpenBlob("main", "test", "col", id, true)
+		if err != nil {
+			return err
+		}
+		defer blob.Close()
+
+		_, err = fmt.Fprint(blob, "Hello BLOB!")
+		return err
+	})
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	var msg string
+	err = conn.QueryRowContext(ctx, `SELECT col FROM test`).Scan(&msg)
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println(msg)
+	// Output:
+	// Hello BLOB!
+}

embed/README.md

@@ -0,0 +1,15 @@
+# Embeddable WASM build of SQLite
+
+This folder includes an embeddable WASM build of SQLite 3.41.0 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
+- FTS3/4/5
+- JSON
+- R*Tree
+- GeoPoly
+
+See the [configuration options](../sqlite3/sqlite_cfg.h).
+
+Built using [`zig`](https://ziglang.org/) version 0.10.1.

embed/build.sh

@@ -8,43 +8,15 @@ cd -P -- "$(dirname -- "$0")"
 
 # build SQLite
 zig cc --target=wasm32-wasi -flto -g0 -Os \
-  -o sqlite3.wasm ../sqlite3/*.c \
+  -o sqlite3.wasm ../sqlite3/main.c \
 	-mmutable-globals \
 	-mbulk-memory -mreference-types \
 	-mnontrapping-fptoint -msign-ext \
 	-D_HAVE_SQLITE_CONFIG_H \
-	-Wl,--export=malloc \
-	-Wl,--export=free \
-	-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_last_insert_rowid \
-	-Wl,--export=sqlite3_changes64 \
-	-Wl,--export=sqlite3_interrupt \
+	$(awk '{print "-Wl,--export="$0}' exports.txt)
+
+# optimize SQLite
+if which wasm-opt; then
+	wasm-opt -g -O -o sqlite3.tmp sqlite3.wasm
+	mv sqlite3.tmp sqlite3.wasm
+fi

embed/exports.txt

@@ -0,0 +1,49 @@
+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
+sqlite3_time_collation
+sqlite3_interrupt_offset

embed/init.go

@@ -1,7 +1,9 @@
 // Package embed embeds SQLite into your application.
 //
-// You can obtain this build of SQLite from:
-// https://github.com/ncruces/go-sqlite3/tree/main/embed
+// Importing package embed initializes the [sqlite3.Binary] variable
+// with an appropriate build of SQLite:
+//
+//	import _ "github.com/ncruces/go-sqlite3/embed"
 package embed
 
 import (

error.go

@@ -1,6 +1,7 @@
 package sqlite3
 
 import (
+	"fmt"
 	"runtime"
 	"strconv"
 	"strings"
@@ -50,29 +51,160 @@ func (e *Error) Error() string {
 	return b.String()
 }
 
+// Is tests whether this error matches a given [ErrorCode] or [ExtendedErrorCode].
+//
+// It makes it possible to do:
+//
+//	if errors.Is(err, sqlite3.BUSY) {
+//		// ... handle BUSY
+//	}
+func (e *Error) Is(err error) bool {
+	switch c := err.(type) {
+	case ErrorCode:
+		return c == e.Code()
+	case ExtendedErrorCode:
+		return c == e.ExtendedCode()
+	}
+	return false
+}
+
 // Temporary returns true for [BUSY] errors.
 func (e *Error) Temporary() bool {
 	return e.Code() == BUSY
 }
 
+// Timeout returns true for [BUSY_TIMEOUT] errors.
+func (e *Error) Timeout() bool {
+	return e.ExtendedCode() == BUSY_TIMEOUT
+}
+
 // SQL returns the SQL starting at the token that triggered a syntax error.
 func (e *Error) SQL() string {
 	return e.sql
 }
 
+// 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"
+}
+
+// Temporary returns true for [BUSY] errors.
+func (e ErrorCode) Temporary() bool {
+	return e == BUSY
+}
+
+// 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"
+}
+
+// Is tests whether this error matches a given [ErrorCode].
+func (e ExtendedErrorCode) Is(err error) bool {
+	c, ok := err.(ErrorCode)
+	return ok && c == ErrorCode(e)
+}
+
+// Temporary returns true for [BUSY] errors.
+func (e ExtendedErrorCode) Temporary() bool {
+	return ErrorCode(e) == BUSY
+}
+
+// Timeout returns true for [BUSY_TIMEOUT] errors.
+func (e ExtendedErrorCode) Timeout() bool {
+	return e == BUSY_TIMEOUT
+}
+
 type errorString string
 
 func (e errorString) Error() string { return string(e) }
 
 const (
-	binaryErr   = errorString("sqlite3: no SQLite binary embed/set/loaded")
 	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")
+	notImplErr  = errorString("sqlite3: not implemented")
+	whenceErr   = errorString("sqlite3: invalid whence")
+	offsetErr   = errorString("sqlite3: invalid offset")
 )
 
 func assertErr() errorString {
@@ -82,3 +214,11 @@ func assertErr() errorString {
 	}
 	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)) }
+}

error_test.go

@@ -1,26 +1,152 @@
 package sqlite3
 
 import (
+	"errors"
 	"strings"
 	"testing"
 )
 
-func TestError(t *testing.T) {
-	err := Error{code: 0x8080}
-	if rc := err.Code(); rc != 0x80 {
-		t.Errorf("got %#x, want 0x80", rc)
-	}
-	if rc := err.ExtendedCode(); rc != 0x8080 {
-		t.Errorf("got %#x, want 0x8080", rc)
-	}
-	if s := err.Error(); s != "sqlite3: 32896" {
+func Test_assertErr(t *testing.T) {
+	err := assertErr()
+	if s := err.Error(); !strings.HasPrefix(s, "sqlite3: assertion failed") || !strings.HasSuffix(s, "error_test.go:10)") {
 		t.Errorf("got %q", s)
 	}
 }
 
-func Test_assertErr(t *testing.T) {
-	err := assertErr()
-	if s := err.Error(); !strings.HasPrefix(s, "sqlite3: assertion failed") || !strings.HasSuffix(s, "error_test.go:22)") {
+func TestError(t *testing.T) {
+	t.Parallel()
+
+	err := Error{code: 0x8080}
+	if rc := err.Code(); rc != 0x80 {
+		t.Errorf("got %#x, want 0x80", rc)
+	}
+	if !errors.Is(&err, ErrorCode(0x80)) {
+		t.Errorf("want true")
+	}
+	if rc := err.ExtendedCode(); rc != 0x8080 {
+		t.Errorf("got %#x, want 0x8080", rc)
+	}
+	if !errors.Is(&err, ExtendedErrorCode(0x8080)) {
+		t.Errorf("want true")
+	}
+	if s := err.Error(); s != "sqlite3: 32896" {
 		t.Errorf("got %q", s)
 	}
+	if !errors.Is(err.ExtendedCode(), ErrorCode(0x80)) {
+		t.Errorf("want true")
+	}
+}
+
+func TestError_Temporary(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name string
+		code uint64
+		want bool
+	}{
+		{"ERROR", uint64(ERROR), false},
+		{"BUSY", uint64(BUSY), true},
+		{"BUSY_RECOVERY", uint64(BUSY_RECOVERY), true},
+		{"BUSY_SNAPSHOT", uint64(BUSY_SNAPSHOT), true},
+		{"BUSY_TIMEOUT", uint64(BUSY_TIMEOUT), true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			{
+				err := &Error{code: tt.code}
+				if got := err.Temporary(); got != tt.want {
+					t.Errorf("Error.Temporary(%d) = %v, want %v", tt.code, got, tt.want)
+				}
+			}
+			{
+				err := ErrorCode(tt.code)
+				if got := err.Temporary(); got != tt.want {
+					t.Errorf("ErrorCode.Temporary(%d) = %v, want %v", tt.code, got, tt.want)
+				}
+			}
+			{
+				err := ExtendedErrorCode(tt.code)
+				if got := err.Temporary(); got != tt.want {
+					t.Errorf("ExtendedErrorCode.Temporary(%d) = %v, want %v", tt.code, got, tt.want)
+				}
+			}
+		})
+	}
+}
+
+func TestError_Timeout(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name string
+		code uint64
+		want bool
+	}{
+		{"ERROR", uint64(ERROR), false},
+		{"BUSY", uint64(BUSY), false},
+		{"BUSY_RECOVERY", uint64(BUSY_RECOVERY), false},
+		{"BUSY_SNAPSHOT", uint64(BUSY_SNAPSHOT), false},
+		{"BUSY_TIMEOUT", uint64(BUSY_TIMEOUT), true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			{
+				err := &Error{code: tt.code}
+				if got := err.Timeout(); got != tt.want {
+					t.Errorf("Error.Timeout(%d) = %v, want %v", tt.code, got, tt.want)
+				}
+			}
+			{
+				err := ExtendedErrorCode(tt.code)
+				if got := err.Timeout(); got != tt.want {
+					t.Errorf("Error.Timeout(%d) = %v, want %v", tt.code, got, tt.want)
+				}
+			}
+		})
+	}
+}
+
+func Test_ErrorCode_Error(t *testing.T) {
+	t.Parallel()
+
+	db, err := Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	// Test all error codes.
+	for i := 0; i == int(ErrorCode(i)); i++ {
+		want := "sqlite3: "
+		r := db.call(db.api.errstr, uint64(i))
+		want += db.mem.readString(uint32(r[0]), _MAX_STRING)
+
+		got := ErrorCode(i).Error()
+		if got != want {
+			t.Fatalf("got %q, want %q, with %d", got, want, i)
+		}
+	}
+}
+
+func Test_ExtendedErrorCode_Error(t *testing.T) {
+	t.Parallel()
+
+	db, err := Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	// Test all extended error codes.
+	for i := 0; i == int(ExtendedErrorCode(i)); i++ {
+		want := "sqlite3: "
+		r := db.call(db.api.errstr, uint64(i))
+		want += db.mem.readString(uint32(r[0]), _MAX_STRING)
+
+		got := ExtendedErrorCode(i).Error()
+		if got != want {
+			t.Fatalf("got %q, want %q, with %d", got, want, i)
+		}
+	}
 }

example_test.go

@@ -21,7 +21,7 @@ func Example() {
 		log.Fatal(err)
 	}
 
-	err = db.Exec(`INSERT INTO users(id, name) VALUES(0, 'go'), (1, 'zig'), (2, 'whatever')`)
+	err = db.Exec(`INSERT INTO users (id, name) VALUES (0, 'go'), (1, 'zig'), (2, 'whatever')`)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -30,6 +30,7 @@ func Example() {
 	if err != nil {
 		log.Fatal(err)
 	}
+	defer stmt.Close()
 
 	for stmt.Step() {
 		fmt.Println(stmt.ColumnInt(0), stmt.ColumnText(1))
@@ -47,7 +48,6 @@ func Example() {
 	if err != nil {
 		log.Fatal(err)
 	}
-
 	// Output:
 	// 0 go
 	// 1 zig

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
+	github.com/tetratelabs/wazero v1.0.0-rc.2
 	golang.org/x/sync v0.1.0
-	golang.org/x/sys v0.5.0
+	golang.org/x/sys v0.6.0
 )
+
+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=
+github.com/tetratelabs/wazero v1.0.0-rc.2 h1:OA3UUynnoqxrjCQ94mpAtdO4/oMxFQVNL2BXDMOc66Q=
+github.com/tetratelabs/wazero v1.0.0-rc.2/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=
+golang.org/x/sys v0.6.0 h1:MVltZSvRTcU2ljQOhs94SXPftV6DCNnZViHeQps87pQ=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

mem.go

@@ -11,17 +11,41 @@ type memory struct {
 	mod api.Module
 }
 
-func (m memory) view(ptr, size uint32) []byte {
+func (m memory) view(ptr uint32, size uint64) []byte {
 	if ptr == 0 {
 		panic(nilErr)
 	}
-	buf, ok := m.mod.Memory().Read(ptr, size)
+	if size > math.MaxUint32 {
+		panic(rangeErr)
+	}
+	buf, ok := m.mod.Memory().Read(ptr, uint32(size))
 	if !ok {
 		panic(rangeErr)
 	}
 	return buf
 }
 
+func (m memory) readUint8(ptr uint32) uint8 {
+	if ptr == 0 {
+		panic(nilErr)
+	}
+	v, ok := m.mod.Memory().ReadByte(ptr)
+	if !ok {
+		panic(rangeErr)
+	}
+	return v
+}
+
+func (m memory) writeUint8(ptr uint32, v uint8) {
+	if ptr == 0 {
+		panic(nilErr)
+	}
+	ok := m.mod.Memory().WriteByte(ptr, v)
+	if !ok {
+		panic(rangeErr)
+	}
+}
+
 func (m memory) readUint32(ptr uint32) uint32 {
 	if ptr == 0 {
 		panic(nilErr)
@@ -33,7 +57,7 @@ func (m memory) readUint32(ptr uint32) uint32 {
 	return v
 }
 
-func (m memory) writeUint32(ptr, v uint32) {
+func (m memory) writeUint32(ptr uint32, v uint32) {
 	if ptr == 0 {
 		panic(nilErr)
 	}
@@ -100,12 +124,12 @@ func (m memory) readString(ptr, maxlen uint32) string {
 }
 
 func (m memory) writeBytes(ptr uint32, b []byte) {
-	buf := m.view(ptr, uint32(len(b)))
+	buf := m.view(ptr, uint64(len(b)))
 	copy(buf, b)
 }
 
 func (m memory) writeString(ptr uint32, s string) {
-	buf := m.view(ptr, uint32(len(s)+1))
+	buf := m.view(ptr, uint64(len(s)+1))
 	buf[len(s)] = 0
 	copy(buf, s)
 }

mem_test.go

@@ -19,6 +19,13 @@ func Test_memory_view_range(t *testing.T) {
 	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)

module.go

@@ -0,0 +1,354 @@
+// Package sqlite3 wraps the C SQLite API.
+package sqlite3
+
+import (
+	"context"
+	"crypto/rand"
+	"io"
+	"math"
+	"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 struct {
+	once      sync.Once
+	runtime   wazero.Runtime
+	compiled  wazero.CompiledModule
+	instances atomic.Uint64
+	err       error
+}
+
+func instantiateModule() (*module, error) {
+	ctx := context.Background()
+
+	sqlite3.once.Do(compileModule)
+	if sqlite3.err != nil {
+		return nil, sqlite3.err
+	}
+
+	name := "sqlite3-" + strconv.FormatUint(sqlite3.instances.Add(1), 10)
+
+	cfg := wazero.NewModuleConfig().WithName(name).
+		WithSysWalltime().WithSysNanotime().WithSysNanosleep().
+		WithOsyield(runtime.Gosched).
+		WithRandSource(rand.Reader)
+
+	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)
+	vfsInstantiate(ctx, sqlite3.runtime)
+
+	bin := Binary
+	if bin == nil && Path != "" {
+		bin, sqlite3.err = os.ReadFile(Path)
+		if sqlite3.err != nil {
+			return
+		}
+	}
+	if bin == nil {
+		sqlite3.err = binaryErr
+		return
+	}
+
+	sqlite3.compiled, sqlite3.err = sqlite3.runtime.CompileModule(ctx, bin)
+}
+
+type module struct {
+	ctx context.Context
+	mem memory
+	api sqliteAPI
+	vfs io.Closer
+}
+
+func newModule(mod api.Module) (m *module, err error) {
+	m = &module{}
+	m.mem = memory{mod}
+	m.ctx, m.vfs = vfsContext(context.Background())
+
+	getFun := func(name string) api.Function {
+		f := mod.ExportedFunction(name)
+		if f == nil {
+			err = noFuncErr + errorString(name)
+			return nil
+		}
+		return f
+	}
+
+	getVal := func(name string) uint32 {
+		global := mod.ExportedGlobal(name)
+		if global == nil {
+			err = noGlobalErr + errorString(name)
+			return 0
+		}
+		return m.mem.readUint32(uint32(global.Get()))
+	}
+
+	m.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"),
+		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"),
+		timeCollation:   getFun("sqlite3_time_collation"),
+		interrupt:       getVal("sqlite3_interrupt_offset"),
+	}
+	if err != nil {
+		return nil, err
+	}
+	return m, nil
+}
+
+func (m *module) close() error {
+	err := m.mem.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(oomErr)
+	}
+
+	var r []uint64
+
+	r = m.call(m.api.errstr, rc)
+	if r != nil {
+		err.str = m.mem.readString(uint32(r[0]), _MAX_STRING)
+	}
+
+	r = m.call(m.api.errmsg, uint64(handle))
+	if r != nil {
+		err.msg = m.mem.readString(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 {
+	r, err := fn.Call(m.ctx, params...)
+	if err != nil {
+		// The module closed or panicked; release resources.
+		m.vfs.Close()
+		panic(err)
+	}
+	return r
+}
+
+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(oomErr)
+	}
+	r := m.call(m.api.malloc, size)
+	ptr := uint32(r[0])
+	if ptr == 0 && size != 0 {
+		panic(oomErr)
+	}
+	return ptr
+}
+
+func (m *module) newBytes(b []byte) uint32 {
+	if b == nil {
+		return 0
+	}
+	ptr := m.new(uint64(len(b)))
+	m.mem.writeBytes(ptr, b)
+	return ptr
+}
+
+func (m *module) newString(s string) uint32 {
+	ptr := m.new(uint64(len(s) + 1))
+	m.mem.writeString(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
+	base uint32
+	next uint32
+	size uint32
+	ptrs []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) string(s string) uint32 {
+	ptr := a.new(uint64(len(s) + 1))
+	a.m.mem.writeString(ptr, s)
+	return ptr
+}
+
+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
+	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
+	timeCollation   api.Function
+	interrupt       uint32
+}

module_test.go

@@ -6,31 +6,64 @@ import (
 	"testing"
 )
 
-func TestConn_new(t *testing.T) {
+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.new(math.MaxUint32)
+	m.error(uint64(NOMEM), 0)
 	t.Error("want panic")
 }
 
+func TestConn_call_nil(t *testing.T) {
+	t.Parallel()
+
+	m, err := instantiateModule()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer m.close()
+
+	defer func() { _ = recover() }()
+	m.call(m.api.free)
+	t.Error("want panic")
+}
+
+func TestConn_new(t *testing.T) {
+	t.Parallel()
+
+	m, err := instantiateModule()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer m.close()
+
+	testOOM := func(size uint64) {
+		defer func() { _ = recover() }()
+		m.new(size)
+		t.Error("want panic")
+	}
+
+	testOOM(math.MaxUint32)
+	testOOM(_MAX_ALLOCATION_SIZE)
+}
+
 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)
-	defer arena.reset()
+	arena := m.newArena(16)
+	defer arena.free()
 
 	const title = "Lorem ipsum"
 
@@ -38,7 +71,7 @@ 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 := m.mem.readString(ptr, math.MaxUint32); got != title {
 		t.Errorf("got %q, want %q", got, title)
 	}
 
@@ -47,33 +80,34 @@ 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 := m.mem.readString(ptr, math.MaxUint32); got != body {
 		t.Errorf("got %q, want %q", got, body)
 	}
+	arena.free()
 }
 
 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, uint32(len(want))); !bytes.Equal(got, want) {
+	if got := m.mem.view(ptr, uint64(len(want))); !bytes.Equal(got, want) {
 		t.Errorf("got %q, want %q", got, want)
 	}
 }
@@ -81,25 +115,25 @@ 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, uint32(len(want))); string(got) != want {
+	if got := m.mem.view(ptr, uint64(len(want))); string(got) != want {
 		t.Errorf("got %q, want %q", got, want)
 	}
 }
@@ -107,40 +141,40 @@ 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 := m.mem.readString(ptr, math.MaxUint32); got != want {
 		t.Errorf("got %q, want %q", got, want)
 	}
-	if got := db.mem.readString(ptr, 0); got != "" {
+	if got := m.mem.readString(ptr, 0); got != "" {
 		t.Errorf("got %q, want empty", got)
 	}
 
 	func() {
 		defer func() { _ = recover() }()
-		db.mem.readString(ptr, uint32(len(want)/2))
+		m.mem.readString(ptr, uint32(len(want)/2))
 		t.Error("want panic")
 	}()
 
 	func() {
 		defer func() { _ = recover() }()
-		db.mem.readString(0, math.MaxUint32)
+		m.mem.readString(0, math.MaxUint32)
 		t.Error("want panic")
 	}()
 }
@@ -148,18 +182,18 @@ 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/download.sh

@@ -4,7 +4,7 @@ set -eo pipefail
 cd -P -- "$(dirname -- "$0")"
 
 if [ ! -f "sqlite3.c" ]; then
-	url="https://www.sqlite.org/2022/sqlite-amalgamation-3400100.zip"
+	url="https://sqlite.org/2023/sqlite-amalgamation-3410100.zip"
 	curl "$url" > sqlite.zip
 	unzip -d . sqlite.zip
 	mv sqlite-amalgamation-*/sqlite3* .

sqlite3/format.sh

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+cd -P -- "$(dirname -- "$0")"
+
+shopt -s extglob
+clang-format -i !(sqlite3*).@(c|h)

sqlite3/main.c

@@ -1,102 +1,20 @@
 #include <stdbool.h>
-#include <stdlib.h>
-#include <time.h>
+#include <stddef.h>
 
-#include "sqlite3.h"
+#include "sqlite3.c"
+//
+#include "os.c"
+#include "qsort.c"
+#include "time.c"
+
+sqlite3_destructor_type malloc_destructor = &free;
+size_t sqlite3_interrupt_offset = offsetof(sqlite3, u1.isInterrupted);
+
+int sqlite3_os_init() {
+  return sqlite3_vfs_register(os_vfs(), /*default=*/true);
+}
 
 int main() {
   int rc = sqlite3_initialize();
   if (rc != SQLITE_OK) return 1;
 }
-
-int go_localtime(sqlite3_int64, struct tm *);
-
-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);
-
-struct go_file {
-  sqlite3_file base;
-  int id;
-  int eLock;
-};
-
-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 *pFile, int op, void *pArg);
-
-int go_lock(sqlite3_file *pFile, int eLock);
-int go_unlock(sqlite3_file *pFile, int eLock);
-int go_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 go_localtime((sqlite3_int64)*pTime, pTm);
-}
-
-static int go_open_c(sqlite3_vfs *vfs, sqlite3_filename zName,
-                     sqlite3_file *file, int flags, int *pOutFlags) {
-  static const sqlite3_io_methods go_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 = no_file_control,
-      .xSectorSize = no_sector_size,
-      .xDeviceCharacteristics = no_device_characteristics,
-  };
-  int rc = go_open(vfs, zName, file, flags, pOutFlags);
-  file->pMethods = (char)rc == SQLITE_OK ? &go_io : NULL;
-  return rc;
-}
-
-int sqlite3_os_init() {
-  static sqlite3_vfs go_vfs = {
-      .iVersion = 2,
-      .szOsFile = sizeof(struct go_file),
-      .mxPathname = 512,
-      .zName = "go",
-
-      .xOpen = go_open_c,
-      .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(&go_vfs, /*default=*/true);
-}
-
-sqlite3_destructor_type malloc_destructor = &free;

sqlite3/os.c

@@ -0,0 +1,144 @@
+#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;
+  char lock;
+  char psow;
+  int lockTimeout;
+};
+
+static_assert(offsetof(struct os_file, id) == 4, "Unexpected offset");
+static_assert(offsetof(struct os_file, lock) == 8, "Unexpected offset");
+static_assert(offsetof(struct os_file, psow) == 9, "Unexpected offset");
+static_assert(offsetof(struct os_file, lockTimeout) == 12, "Unexpected offset");
+
+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 *, int op, void *pArg);
+
+int os_lock(sqlite3_file *, int eLock);
+int os_unlock(sqlite3_file *, int eLock);
+int os_check_reserved_lock(sqlite3_file *, int *pResOut);
+
+static int os_file_control_w(sqlite3_file *file, int op, void *pArg) {
+  struct os_file *pFile = (struct os_file *)file;
+  switch (op) {
+    case SQLITE_FCNTL_VFSNAME: {
+      *(char **)pArg = sqlite3_mprintf("%s", "os");
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_LOCKSTATE: {
+      *(int *)pArg = pFile->lock;
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_LOCK_TIMEOUT: {
+      int iOld = pFile->lockTimeout;
+      pFile->lockTimeout = *(int *)pArg;
+      *(int *)pArg = iOld;
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_POWERSAFE_OVERWRITE: {
+      if (*(int *)pArg < 0) {
+        *(int *)pArg = pFile->psow;
+      } else {
+        pFile->psow = *(int *)pArg;
+      }
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_SIZE_HINT:
+    case SQLITE_FCNTL_HAS_MOVED:
+      return os_file_control(file, op, pArg);
+  }
+  // Consider also implementing these opcodes (in use by SQLite):
+  //  SQLITE_FCNTL_BUSYHANDLER
+  //  SQLITE_FCNTL_COMMIT_PHASETWO
+  //  SQLITE_FCNTL_PDB
+  //  SQLITE_FCNTL_PRAGMA
+  //  SQLITE_FCNTL_SYNC
+  return SQLITE_NOTFOUND;
+}
+
+static int os_sector_size(sqlite3_file *file) {
+  return SQLITE_DEFAULT_SECTOR_SIZE;
+}
+
+static int os_device_characteristics(sqlite3_file *file) {
+  struct os_file *pFile = (struct os_file *)file;
+  return pFile->psow ? SQLITE_IOCAP_POWERSAFE_OVERWRITE : 0;
+}
+
+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 = os_file_control_w,
+      .xSectorSize = os_sector_size,
+      .xDeviceCharacteristics = os_device_characteristics,
+  };
+  memset(file, 0, sizeof(struct os_file));
+  int rc = os_open(vfs, zName, file, flags, pOutFlags);
+  if (rc) {
+    return rc;
+  }
+
+  struct os_file *pFile = (struct os_file *)file;
+  pFile->base.pMethods = &os_io;
+  if (flags & SQLITE_OPEN_MAIN_DB) {
+    pFile->psow =
+        sqlite3_uri_boolean(zName, "psow", SQLITE_POWERSAFE_OVERWRITE);
+  }
+  return SQLITE_OK;
+}
+
+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;
+}
+
+int localtime_s(struct tm *const pTm, time_t const *const pTime) {
+  return os_localtime((sqlite3_int64)*pTime, pTm);
+}

sqlite3/qsort.c

@@ -0,0 +1,14 @@
+#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

@@ -28,18 +28,35 @@
 #define SQLITE_OMIT_AUTOINIT
 #define SQLITE_USE_ALLOCA
 
+// Because WASM does not support shared memory,
+// SQLite disables it 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
 
-// #define SQLITE_ENABLE_MATH_FUNCTIONS 1
-// #define SQLITE_ENABLE_FTS3 1
-// #define SQLITE_ENABLE_FTS3_PARENTHESIS 1
-// #define SQLITE_ENABLE_FTS4 1
-// #define SQLITE_ENABLE_FTS5 1
-// #define SQLITE_ENABLE_RTREE 1
-// #define SQLITE_ENABLE_GEOPOLY 1
+#define SQLITE_ENABLE_MATH_FUNCTIONS 1
+#define SQLITE_ENABLE_JSON1 1
+#define SQLITE_ENABLE_FTS3 1
+#define SQLITE_ENABLE_FTS3_PARENTHESIS 1
+#define SQLITE_ENABLE_FTS4 1
+#define SQLITE_ENABLE_FTS5 1
+#define SQLITE_ENABLE_RTREE 1
+#define SQLITE_ENABLE_GEOPOLY 1
 
-// Need this to access WAL databases without the use of shared memory.
-#define SQLITE_DEFAULT_LOCKING_MODE 1
+// Snapshot
+// #define SQLITE_ENABLE_SNAPSHOT 1
+
+// Session Extension
+// #define SQLITE_ENABLE_SESSION 1
+// #define SQLITE_ENABLE_PREUPDATE_HOOK 1
+
+// Resumable Bulk Update Extension
+// #define SQLITE_ENABLE_RBU 1
 
 // Implemented in Go.
 int localtime_s(struct tm *const pTm, time_t const *const pTime);

sqlite3/time.c

@@ -0,0 +1,31 @@
+#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_collation(sqlite3 *db) {
+  return sqlite3_create_collation(db, "TIME", SQLITE_UTF8, 0, time_collation);
+}

stmt.go

@@ -16,7 +16,7 @@ type Stmt struct {
 
 // Close destroys the prepared statement object.
 //
-// It is safe to close a nil, zero or closed prepared statement.
+// It is safe to close a nil, zero or closed Stmt.
 //
 // https://www.sqlite.org/c3ref/finalize.html
 func (s *Stmt) Close() error {
@@ -24,10 +24,7 @@ func (s *Stmt) Close() error {
 		return nil
 	}
 
-	r, err := s.c.api.finalize.Call(s.c.ctx, uint64(s.handle))
-	if err != nil {
-		panic(err)
-	}
+	r := s.c.call(s.c.api.finalize, uint64(s.handle))
 
 	s.handle = 0
 	return s.c.error(r[0])
@@ -37,10 +34,7 @@ func (s *Stmt) Close() error {
 //
 // https://www.sqlite.org/c3ref/reset.html
 func (s *Stmt) Reset() error {
-	r, err := s.c.api.reset.Call(s.c.ctx, uint64(s.handle))
-	if err != nil {
-		panic(err)
-	}
+	r := s.c.call(s.c.api.reset, uint64(s.handle))
 	s.err = nil
 	return s.c.error(r[0])
 }
@@ -49,10 +43,7 @@ func (s *Stmt) Reset() error {
 //
 // https://www.sqlite.org/c3ref/clear_bindings.html
 func (s *Stmt) ClearBindings() error {
-	r, err := s.c.api.clearBindings.Call(s.c.ctx, uint64(s.handle))
-	if err != nil {
-		panic(err)
-	}
+	r := s.c.call(s.c.api.clearBindings, uint64(s.handle))
 	return s.c.error(r[0])
 }
 
@@ -66,10 +57,8 @@ func (s *Stmt) ClearBindings() error {
 //
 // https://www.sqlite.org/c3ref/step.html
 func (s *Stmt) Step() bool {
-	r, err := s.c.api.step.Call(s.c.ctx, uint64(s.handle))
-	if err != nil {
-		panic(err)
-	}
+	s.c.checkInterrupt()
+	r := s.c.call(s.c.api.step, uint64(s.handle))
 	if r[0] == _ROW {
 		return true
 	}
@@ -101,11 +90,8 @@ func (s *Stmt) Exec() error {
 //
 // https://www.sqlite.org/c3ref/bind_parameter_count.html
 func (s *Stmt) BindCount() int {
-	r, err := s.c.api.bindCount.Call(s.c.ctx,
+	r := s.c.call(s.c.api.bindCount,
 		uint64(s.handle))
-	if err != nil {
-		panic(err)
-	}
 	return int(r[0])
 }
 
@@ -116,11 +102,8 @@ func (s *Stmt) BindCount() int {
 func (s *Stmt) BindIndex(name string) int {
 	defer s.c.arena.reset()
 	namePtr := s.c.arena.string(name)
-	r, err := s.c.api.bindIndex.Call(s.c.ctx,
+	r := s.c.call(s.c.api.bindIndex,
 		uint64(s.handle), uint64(namePtr))
-	if err != nil {
-		panic(err)
-	}
 	return int(r[0])
 }
 
@@ -129,11 +112,8 @@ func (s *Stmt) BindIndex(name string) int {
 //
 // https://www.sqlite.org/c3ref/bind_parameter_name.html
 func (s *Stmt) BindName(param int) string {
-	r, err := s.c.api.bindName.Call(s.c.ctx,
+	r := s.c.call(s.c.api.bindName,
 		uint64(s.handle), uint64(param))
-	if err != nil {
-		panic(err)
-	}
 
 	ptr := uint32(r[0])
 	if ptr == 0 {
@@ -168,11 +148,8 @@ func (s *Stmt) BindInt(param int, value int) error {
 //
 // https://www.sqlite.org/c3ref/bind_blob.html
 func (s *Stmt) BindInt64(param int, value int64) error {
-	r, err := s.c.api.bindInteger.Call(s.c.ctx,
+	r := s.c.call(s.c.api.bindInteger,
 		uint64(s.handle), uint64(param), uint64(value))
-	if err != nil {
-		panic(err)
-	}
 	return s.c.error(r[0])
 }
 
@@ -181,11 +158,8 @@ func (s *Stmt) BindInt64(param int, value int64) error {
 //
 // https://www.sqlite.org/c3ref/bind_blob.html
 func (s *Stmt) BindFloat(param int, value float64) error {
-	r, err := s.c.api.bindFloat.Call(s.c.ctx,
+	r := s.c.call(s.c.api.bindFloat,
 		uint64(s.handle), uint64(param), math.Float64bits(value))
-	if err != nil {
-		panic(err)
-	}
 	return s.c.error(r[0])
 }
 
@@ -195,13 +169,10 @@ func (s *Stmt) BindFloat(param int, value float64) error {
 // https://www.sqlite.org/c3ref/bind_blob.html
 func (s *Stmt) BindText(param int, value string) error {
 	ptr := s.c.newString(value)
-	r, err := s.c.api.bindText.Call(s.c.ctx,
+	r := s.c.call(s.c.api.bindText,
 		uint64(s.handle), uint64(param),
 		uint64(ptr), uint64(len(value)),
 		s.c.api.destructor, _UTF8)
-	if err != nil {
-		panic(err)
-	}
 	return s.c.error(r[0])
 }
 
@@ -212,13 +183,10 @@ func (s *Stmt) BindText(param int, value string) error {
 // https://www.sqlite.org/c3ref/bind_blob.html
 func (s *Stmt) BindBlob(param int, value []byte) error {
 	ptr := s.c.newBytes(value)
-	r, err := s.c.api.bindBlob.Call(s.c.ctx,
+	r := s.c.call(s.c.api.bindBlob,
 		uint64(s.handle), uint64(param),
 		uint64(ptr), uint64(len(value)),
 		s.c.api.destructor)
-	if err != nil {
-		panic(err)
-	}
 	return s.c.error(r[0])
 }
 
@@ -227,11 +195,8 @@ func (s *Stmt) BindBlob(param int, value []byte) error {
 //
 // https://www.sqlite.org/c3ref/bind_blob.html
 func (s *Stmt) BindZeroBlob(param int, n int64) error {
-	r, err := s.c.api.bindZeroBlob.Call(s.c.ctx,
+	r := s.c.call(s.c.api.bindZeroBlob,
 		uint64(s.handle), uint64(param), uint64(n))
-	if err != nil {
-		panic(err)
-	}
 	return s.c.error(r[0])
 }
 
@@ -240,11 +205,8 @@ func (s *Stmt) BindZeroBlob(param int, n int64) error {
 //
 // https://www.sqlite.org/c3ref/bind_blob.html
 func (s *Stmt) BindNull(param int) error {
-	r, err := s.c.api.bindNull.Call(s.c.ctx,
+	r := s.c.call(s.c.api.bindNull,
 		uint64(s.handle), uint64(param))
-	if err != nil {
-		panic(err)
-	}
 	return s.c.error(r[0])
 }
 
@@ -270,11 +232,8 @@ func (s *Stmt) BindTime(param int, value time.Time, format TimeFormat) error {
 //
 // https://www.sqlite.org/c3ref/column_count.html
 func (s *Stmt) ColumnCount() int {
-	r, err := s.c.api.columnCount.Call(s.c.ctx,
+	r := s.c.call(s.c.api.columnCount,
 		uint64(s.handle))
-	if err != nil {
-		panic(err)
-	}
 	return int(r[0])
 }
 
@@ -283,11 +242,8 @@ func (s *Stmt) ColumnCount() int {
 //
 // https://www.sqlite.org/c3ref/column_name.html
 func (s *Stmt) ColumnName(col int) string {
-	r, err := s.c.api.columnName.Call(s.c.ctx,
+	r := s.c.call(s.c.api.columnName,
 		uint64(s.handle), uint64(col))
-	if err != nil {
-		panic(err)
-	}
 
 	ptr := uint32(r[0])
 	if ptr == 0 {
@@ -301,11 +257,8 @@ func (s *Stmt) ColumnName(col int) string {
 //
 // https://www.sqlite.org/c3ref/column_blob.html
 func (s *Stmt) ColumnType(col int) Datatype {
-	r, err := s.c.api.columnType.Call(s.c.ctx,
+	r := s.c.call(s.c.api.columnType,
 		uint64(s.handle), uint64(col))
-	if err != nil {
-		panic(err)
-	}
 	return Datatype(r[0])
 }
 
@@ -336,11 +289,8 @@ func (s *Stmt) ColumnInt(col int) int {
 //
 // https://www.sqlite.org/c3ref/column_blob.html
 func (s *Stmt) ColumnInt64(col int) int64 {
-	r, err := s.c.api.columnInteger.Call(s.c.ctx,
+	r := s.c.call(s.c.api.columnInteger,
 		uint64(s.handle), uint64(col))
-	if err != nil {
-		panic(err)
-	}
 	return int64(r[0])
 }
 
@@ -349,11 +299,8 @@ func (s *Stmt) ColumnInt64(col int) int64 {
 //
 // https://www.sqlite.org/c3ref/column_blob.html
 func (s *Stmt) ColumnFloat(col int) float64 {
-	r, err := s.c.api.columnFloat.Call(s.c.ctx,
+	r := s.c.call(s.c.api.columnFloat,
 		uint64(s.handle), uint64(col))
-	if err != nil {
-		panic(err)
-	}
 	return math.Float64frombits(r[0])
 }
 
@@ -387,29 +334,20 @@ 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, err := s.c.api.columnText.Call(s.c.ctx,
+	r := s.c.call(s.c.api.columnText,
 		uint64(s.handle), uint64(col))
-	if err != nil {
-		panic(err)
-	}
 
 	ptr := uint32(r[0])
 	if ptr == 0 {
-		r, err = s.c.api.errcode.Call(s.c.ctx, uint64(s.handle))
-		if err != nil {
-			panic(err)
-		}
+		r = s.c.call(s.c.api.errcode, uint64(s.c.handle))
 		s.err = s.c.error(r[0])
 		return ""
 	}
 
-	r, err = s.c.api.columnBytes.Call(s.c.ctx,
+	r = s.c.call(s.c.api.columnBytes,
 		uint64(s.handle), uint64(col))
-	if err != nil {
-		panic(err)
-	}
 
-	mem := s.c.mem.view(ptr, uint32(r[0]))
+	mem := s.c.mem.view(ptr, r[0])
 	return string(mem)
 }
 
@@ -419,28 +357,34 @@ 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, err := s.c.api.columnBlob.Call(s.c.ctx,
+	r := s.c.call(s.c.api.columnBlob,
 		uint64(s.handle), uint64(col))
-	if err != nil {
-		panic(err)
-	}
 
 	ptr := uint32(r[0])
 	if ptr == 0 {
-		r, err = s.c.api.errcode.Call(s.c.ctx, uint64(s.handle))
-		if err != nil {
-			panic(err)
-		}
+		r = s.c.call(s.c.api.errcode, uint64(s.c.handle))
 		s.err = s.c.error(r[0])
 		return buf[0:0]
 	}
 
-	r, err = s.c.api.columnBytes.Call(s.c.ctx,
+	r = s.c.call(s.c.api.columnBytes,
 		uint64(s.handle), uint64(col))
-	if err != nil {
-		panic(err)
-	}
 
-	mem := s.c.mem.view(ptr, uint32(r[0]))
+	mem := s.c.mem.view(ptr, r[0])
 	return append(buf[0:0], mem...)
 }
+
+// Return true if stmt is an empty SQL statement.
+// This is used as an optimization.
+// It's OK to always return false here.
+func emptyStatement(stmt string) bool {
+	for _, b := range []byte(stmt) {
+		switch b {
+		case ' ', '\n', '\r', '\t', '\v', '\f':
+		case ';':
+		default:
+			return false
+		}
+	}
+	return true
+}

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

@@ -0,0 +1,297 @@
+package tests
+
+import (
+	"bytes"
+	"crypto/rand"
+	"errors"
+	"fmt"
+	"io"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+	_ "github.com/ncruces/go-sqlite3/embed"
+)
+
+func TestBlob(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()
+
+	size := blob.Size()
+	if size != 1024 {
+		t.Errorf("got %d, want 1024", size)
+	}
+
+	var data [1280]byte
+	_, err = rand.Read(data[:])
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = io.Copy(blob, bytes.NewReader(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")
+	}
+
+	_, err = io.Copy(blob, bytes.NewReader(data[size/2:size]))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = blob.Seek(size/4, io.SeekStart)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if got, err := io.ReadAll(blob); err != nil {
+		t.Fatal(err)
+	} else if !bytes.Equal(got, data[size/4:size]) {
+		t.Errorf("got %q, want %q", got, data[size/4:size])
+	}
+
+	if n, err := blob.Read(make([]byte, 1)); n != 0 || err != io.EOF {
+		t.Errorf("got (%d, %v), want (0, EOF)", 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()
+
+	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)
+	}
+
+	_, err = db.OpenBlob("", "test", "col", db.LastInsertRowID(), false)
+	if !errors.Is(err, sqlite3.ERROR) {
+		t.Fatal("want error")
+	}
+}
+
+func TestBlob_Write_readonly(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(), false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer blob.Close()
+
+	_, err = blob.Write([]byte("data"))
+	if !errors.Is(err, sqlite3.READONLY) {
+		t.Fatal("want error")
+	}
+}
+
+func TestBlob_Read_expired(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(), false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer blob.Close()
+
+	err = db.Exec(`DELETE FROM test`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = io.ReadAll(blob)
+	if !errors.Is(err, sqlite3.ABORT) {
+		t.Fatal("want error", err)
+	}
+}
+
+func TestBlob_Seek(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()
+
+	_, err = blob.Seek(0, 10)
+	if err == nil {
+		t.Fatal("want error")
+	}
+
+	_, err = blob.Seek(-1, io.SeekCurrent)
+	if err == nil {
+		t.Fatal("want error")
+	}
+
+	n, err := blob.Seek(1, io.SeekEnd)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if n != blob.Size()+1 {
+		t.Errorf("got %d, want %d", n, blob.Size())
+	}
+
+	_, err = blob.Write([]byte("data"))
+	if !errors.Is(err, sqlite3.ERROR) {
+		t.Fatal("want error")
+	}
+}
+
+func TestBlob_Reopen(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)
+	}
+
+	var rowids []int64
+	for i := 0; i < 100; i++ {
+		err = db.Exec(`INSERT INTO test VALUES (zeroblob(10))`)
+		if err != nil {
+			t.Fatal(err)
+		}
+		rowids = append(rowids, db.LastInsertRowID())
+	}
+
+	var blob *sqlite3.Blob
+
+	for i, rowid := range rowids {
+		if i > 0 {
+			err = blob.Reopen(rowid)
+		} else {
+			blob, err = db.OpenBlob("main", "test", "col", rowid, true)
+		}
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		_, err = fmt.Fprintf(blob, "blob %d\n", i)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+	if err := blob.Close(); err != nil {
+		t.Fatal(err)
+	}
+
+	for i, rowid := range rowids {
+		if i > 0 {
+			err = blob.Reopen(rowid)
+		} else {
+			blob, err = db.OpenBlob("main", "test", "col", rowid, false)
+		}
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		var got int
+		_, err = fmt.Fscanf(blob, "blob %d\n", &got)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if got != i {
+			t.Errorf("got %d, want %d", got, i)
+		}
+	}
+	if err := blob.Close(); err != nil {
+		t.Fatal(err)
+	}
+}

tests/bradfitz/sql_test.go

@@ -41,7 +41,9 @@ func (t params) mustExec(sql string, args ...interface{}) sql.Result {
 }
 
 func (sqliteDB) RunTest(t *testing.T, fn func(params)) {
-	db, err := sql.Open("sqlite3", filepath.Join(t.TempDir(), "foo.db"))
+	db, err := sql.Open("sqlite3", "file:"+
+		filepath.Join(t.TempDir(), "foo.db")+
+		"?_pragma=busy_timeout(10000)&_pragma=locking_mode(normal)&_pragma=synchronous(off)")
 	if err != nil {
 		t.Fatalf("foo.db open fail: %v", err)
 	}
@@ -104,7 +106,7 @@ func testTxQuery(t params) {
 	}
 	defer tx.Rollback()
 
-	_, err = t.DB.Exec("create table " + TablePrefix + "foo (id integer primary key, name varchar(50))")
+	_, err = tx.Exec("create table " + TablePrefix + "foo (id integer primary key, name varchar(50))")
 	if err != nil {
 		t.Logf("cannot drop table "+TablePrefix+"foo: %s", err)
 	}

tests/conn_test.go

@@ -13,19 +13,12 @@ import (
 func TestConn_Open_dir(t *testing.T) {
 	t.Parallel()
 
-	_, err := sqlite3.Open(".")
+	_, err := sqlite3.OpenFlags(".", 0)
 	if err == nil {
 		t.Fatal("want error")
 	}
-	var serr *sqlite3.Error
-	if !errors.As(err, &serr) {
-		t.Fatalf("got %T, want sqlite3.Error", err)
-	}
-	if rc := serr.Code(); rc != sqlite3.CANTOPEN {
-		t.Errorf("got %d, want sqlite3.CANTOPEN", rc)
-	}
-	if got := err.Error(); got != `sqlite3: unable to open database file` {
-		t.Error("got message: ", got)
+	if !errors.Is(err, sqlite3.CANTOPEN) {
+		t.Errorf("got %v, want sqlite3.CANTOPEN", err)
 	}
 }
 
@@ -53,23 +46,21 @@ func TestConn_Close_BUSY(t *testing.T) {
 	if err == nil {
 		t.Fatal("want error")
 	}
-	var serr *sqlite3.Error
-	if !errors.As(err, &serr) {
-		t.Fatalf("got %T, want sqlite3.Error", err)
-	}
-	if rc := serr.Code(); rc != sqlite3.BUSY {
-		t.Errorf("got %d, want sqlite3.BUSY", rc)
+	if !errors.Is(err, sqlite3.BUSY) {
+		t.Errorf("got %v, want sqlite3.BUSY", err)
 	}
 	var terr interface{ Temporary() bool }
 	if !errors.As(err, &terr) || !terr.Temporary() {
 		t.Error("not temporary", err)
 	}
 	if got := err.Error(); got != `sqlite3: database is locked: unable to close due to unfinalized statements or unfinished backups` {
-		t.Error("got message: ", got)
+		t.Error("got message:", got)
 	}
 }
 
 func TestConn_SetInterrupt(t *testing.T) {
+	t.Parallel()
+
 	db, err := sqlite3.Open(":memory:")
 	if err != nil {
 		t.Fatal(err)
@@ -77,7 +68,7 @@ func TestConn_SetInterrupt(t *testing.T) {
 	defer db.Close()
 
 	ctx, cancel := context.WithCancel(context.Background())
-	db.SetInterrupt(ctx.Done())
+	db.SetInterrupt(ctx)
 
 	// Interrupt doesn't interrupt this.
 	err = db.Exec(`SELECT 1`)
@@ -85,7 +76,7 @@ func TestConn_SetInterrupt(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	db.SetInterrupt(nil)
+	db.SetInterrupt(context.Background())
 
 	stmt, _, err := db.Prepare(`
 		WITH RECURSIVE
@@ -103,40 +94,24 @@ func TestConn_SetInterrupt(t *testing.T) {
 	}
 	defer stmt.Close()
 
+	db.SetInterrupt(ctx)
 	cancel()
-	db.SetInterrupt(ctx.Done())
-
-	var serr *sqlite3.Error
 
 	// Interrupting works.
 	err = stmt.Exec()
-	if err != nil {
-		if !errors.As(err, &serr) {
-			t.Fatalf("got %T, want sqlite3.Error", err)
-		}
-		if rc := serr.Code(); rc != sqlite3.INTERRUPT {
-			t.Errorf("got %d, want sqlite3.INTERRUPT", rc)
-		}
-		if got := err.Error(); got != `sqlite3: interrupted` {
-			t.Error("got message: ", got)
-		}
+	if !errors.Is(err, sqlite3.INTERRUPT) {
+		t.Errorf("got %v, want sqlite3.INTERRUPT", err)
 	}
 
 	// Interrupting sticks.
 	err = db.Exec(`SELECT 1`)
-	if err != nil {
-		if !errors.As(err, &serr) {
-			t.Fatalf("got %T, want sqlite3.Error", err)
-		}
-		if rc := serr.Code(); rc != sqlite3.INTERRUPT {
-			t.Errorf("got %d, want sqlite3.INTERRUPT", rc)
-		}
-		if got := err.Error(); got != `sqlite3: interrupted` {
-			t.Error("got message: ", got)
-		}
+	if !errors.Is(err, sqlite3.INTERRUPT) {
+		t.Errorf("got %v, want sqlite3.INTERRUPT", err)
 	}
 
-	db.SetInterrupt(nil)
+	ctx, cancel = context.WithCancel(context.Background())
+	defer cancel()
+	db.SetInterrupt(ctx)
 
 	// Interrupting can be cleared.
 	err = db.Exec(`SELECT 1`)
@@ -207,7 +182,7 @@ func TestConn_Prepare_invalid(t *testing.T) {
 		t.Errorf("got %d, want sqlite3.ERROR", rc)
 	}
 	if got := err.Error(); got != `sqlite3: SQL logic error: incomplete input` {
-		t.Error("got message: ", got)
+		t.Error("got message:", got)
 	}
 
 	_, _, err = db.Prepare(`SELECT * FRM sqlite_schema`)
@@ -221,9 +196,9 @@ func TestConn_Prepare_invalid(t *testing.T) {
 		t.Errorf("got %d, want sqlite3.ERROR", rc)
 	}
 	if got := serr.SQL(); got != `FRM sqlite_schema` {
-		t.Error("got SQL: ", got)
+		t.Error("got SQL:", got)
 	}
 	if got := serr.Error(); got != `sqlite3: SQL logic error: near "FRM": syntax error` {
-		t.Error("got message: ", got)
+		t.Error("got message:", got)
 	}
 }

tests/db_test.go

@@ -30,7 +30,7 @@ func testDB(t *testing.T, name string) {
 		t.Fatal(err)
 	}
 
-	err = db.Exec(`INSERT INTO users(id, name) VALUES(0, 'go'), (1, 'zig'), (2, 'whatever')`)
+	err = db.Exec(`INSERT INTO users (id, name) VALUES (0, 'go'), (1, 'zig'), (2, 'whatever')`)
 	if err != nil {
 		t.Fatal(err)
 	}

tests/driver_test.go

@@ -34,7 +34,7 @@ func TestDriver(t *testing.T) {
 	}
 
 	res, err := conn.ExecContext(ctx,
-		`INSERT INTO users(id, name) VALUES(0, 'go'), (1, 'zig'), (2, 'whatever')`)
+		`INSERT INTO users (id, name) VALUES (0, 'go'), (1, 'zig'), (2, 'whatever')`)
 	if err != nil {
 		t.Fatal(err)
 	}

tests/mptest/mptest_test.go

@@ -0,0 +1,186 @@
+package mptest
+
+import (
+	"bytes"
+	"context"
+	"crypto/rand"
+	"embed"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"testing"
+
+	_ "unsafe"
+
+	"github.com/tetratelabs/wazero"
+	"github.com/tetratelabs/wazero/api"
+	"github.com/tetratelabs/wazero/imports/wasi_snapshot_preview1"
+
+	_ "github.com/ncruces/go-sqlite3"
+)
+
+//go:embed testdata/mptest.wasm
+var binary []byte
+
+//go:embed testdata/*.*test
+var scripts embed.FS
+
+//go:linkname vfsNewEnvModuleBuilder github.com/ncruces/go-sqlite3.vfsNewEnvModuleBuilder
+func vfsNewEnvModuleBuilder(r wazero.Runtime) wazero.HostModuleBuilder
+
+//go:linkname vfsContext github.com/ncruces/go-sqlite3.vfsContext
+func vfsContext(ctx context.Context) (context.Context, io.Closer)
+
+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 := vfsNewEnvModuleBuilder(rt)
+	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 := vfsContext(ctx)
+		rt.InstantiateModule(ctx, module, cfg)
+		vfs.Close()
+	}()
+	return 0
+}
+
+func Test_config01(t *testing.T) {
+	ctx, vfs := vfsContext(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)
+	}
+	vfs.Close()
+	mod.Close(ctx)
+}
+
+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 := vfsContext(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)
+	}
+	vfs.Close()
+	mod.Close(ctx)
+}
+
+func Test_crash01(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping in short mode")
+	}
+
+	ctx, vfs := vfsContext(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)
+	}
+	vfs.Close()
+	mod.Close(ctx)
+}
+
+func Test_multiwrite01(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping in short mode")
+	}
+
+	ctx, vfs := vfsContext(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)
+	}
+	vfs.Close()
+	mod.Close(ctx)
+}
+
+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
+	}
+}

tests/mptest/testdata/.gitattributes

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

tests/mptest/testdata/.gitignore

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

tests/mptest/testdata/build.sh

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+set -eo pipefail
+
+cd -P -- "$(dirname -- "$0")"
+
+if [ ! -f "mptest.c" ]; then
+	curl -sOL	"https://github.com/sqlite/sqlite/raw/version-3.41.1/mptest/mptest.c"
+	curl -sOL "https://github.com/sqlite/sqlite/raw/version-3.41.1/mptest/config01.test"
+  curl -sOL "https://github.com/sqlite/sqlite/raw/version-3.41.1/mptest/config02.test"
+  curl -sOL "https://github.com/sqlite/sqlite/raw/version-3.41.1/mptest/crash01.test"
+  curl -sOL "https://github.com/sqlite/sqlite/raw/version-3.41.1/mptest/crash02.subtest"
+  curl -sOL "https://github.com/sqlite/sqlite/raw/version-3.41.1/mptest/multiwrite01.test"
+fi
+
+zig cc --target=wasm32-wasi -flto -g0 -Os \
+  -o mptest.wasm main.c \
+	-I../../../sqlite3 \
+	-mmutable-globals \
+	-mbulk-memory -mreference-types \
+	-mnontrapping-fptoint -msign-ext \
+	-D_HAVE_SQLITE_CONFIG_H \
+	-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
+
+if which wasm-opt; then
+	wasm-opt -g -O -o mptest.tmp mptest.wasm
+	mv mptest.tmp mptest.wasm
+fi

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

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

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

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

tests/mptest/testdata/main.c

@@ -0,0 +1,24 @@
+#include <stdbool.h>
+#include <stddef.h>
+
+#include "sqlite3.c"
+//
+#include "os.c"
+#include "qsort.c"
+#include "time.c"
+
+sqlite3_destructor_type malloc_destructor = &free;
+size_t sqlite3_interrupt_offset = offsetof(sqlite3, u1.isInterrupted);
+
+int sqlite3_os_init() {
+  return sqlite3_vfs_register(os_vfs(), /*default=*/true);
+}
+
+__attribute__((constructor)) void premain() { 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"

tests/mptest/testdata/mptest.wasm

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:af307c3555fcf5f78e07a079d8f099400c3e013508f30f5efbe3b7f259be2092
+size 969309

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

tests/parallel/parallel_test.go

@@ -1,7 +1,6 @@
 package tests
 
 import (
-	"errors"
 	"io"
 	"os"
 	"os/exec"
@@ -15,14 +14,21 @@ 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, 100)
+	testParallel(t, name, iter)
 	testIntegrity(t, name)
 }
 
 func TestMultiProcess(t *testing.T) {
 	if testing.Short() {
-		t.Skip()
+		t.Skip("skipping in short mode")
 	}
 
 	name := filepath.Join(t.TempDir(), "test.db")
@@ -46,10 +52,6 @@ func TestMultiProcess(t *testing.T) {
 	testParallel(t, name, 1000)
 	if err := cmd.Wait(); err != nil {
 		t.Error(err)
-		var eerr *exec.ExitError
-		if errors.As(err, &eerr) {
-			t.Error(eerr.Stderr)
-		}
 	}
 	testIntegrity(t, name)
 }
@@ -72,8 +74,10 @@ func testParallel(t *testing.T, name string, n int) {
 		defer db.Close()
 
 		err = db.Exec(`
-			PRAGMA locking_mode = NORMAL;
-			PRAGMA busy_timeout = 10000;
+			PRAGMA busy_timeout=10000;
+			PRAGMA synchronous=off;
+			PRAGMA locking_mode=normal;
+			PRAGMA journal_mode=truncate;
 		`)
 		if err != nil {
 			return err
@@ -84,7 +88,7 @@ func testParallel(t *testing.T, name string, n int) {
 			return err
 		}
 
-		err = db.Exec(`INSERT INTO users(id, name) VALUES(0, 'go'), (1, 'zig'), (2, 'whatever')`)
+		err = db.Exec(`INSERT INTO users (id, name) VALUES (0, 'go'), (1, 'zig'), (2, 'whatever')`)
 		if err != nil {
 			return err
 		}
@@ -100,8 +104,8 @@ func testParallel(t *testing.T, name string, n int) {
 		defer db.Close()
 
 		err = db.Exec(`
-			PRAGMA locking_mode = NORMAL;
-			PRAGMA busy_timeout = 10000;
+			PRAGMA busy_timeout=10000;
+			PRAGMA locking_mode=normal;
 		`)
 		if err != nil {
 			return err
@@ -138,7 +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)
@@ -148,7 +152,7 @@ func testParallel(t *testing.T, name string, n int) {
 	}
 	err = group.Wait()
 	if err != nil {
-		t.Fatal(err)
+		t.Error(err)
 	}
 }
 

tests/speedtest1/speedtest1_test.go

@@ -0,0 +1,92 @@
+package speedtest1
+
+import (
+	"bytes"
+	"context"
+	"crypto/rand"
+	"io"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"strings"
+	"testing"
+
+	_ "embed"
+	_ "unsafe"
+
+	"github.com/tetratelabs/wazero"
+	"github.com/tetratelabs/wazero/imports/wasi_snapshot_preview1"
+
+	_ "github.com/ncruces/go-sqlite3"
+)
+
+//go:embed testdata/speedtest1.wasm
+var binary []byte
+
+//go:linkname vfsNewEnvModuleBuilder github.com/ncruces/go-sqlite3.vfsNewEnvModuleBuilder
+func vfsNewEnvModuleBuilder(r wazero.Runtime) wazero.HostModuleBuilder
+
+//go:linkname vfsContext github.com/ncruces/go-sqlite3.vfsContext
+func vfsContext(ctx context.Context) (context.Context, io.Closer)
+
+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 := vfsNewEnvModuleBuilder(rt)
+	_, 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 := vfsContext(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)
+	}
+	vfs.Close()
+	mod.Close(ctx)
+}

tests/speedtest1/testdata/.gitattributes

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

tests/speedtest1/testdata/.gitignore

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

tests/speedtest1/testdata/build.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+set -eo pipefail
+
+cd -P -- "$(dirname -- "$0")"
+
+if [ ! -f "mptest.c" ]; then
+	curl -sOL	"https://github.com/sqlite/sqlite/raw/version-3.41.1/test/speedtest1.c"
+fi
+
+zig cc --target=wasm32-wasi -flto -g0 -Os \
+  -o speedtest1.wasm main.c \
+	-I../../../sqlite3 \
+	-mmutable-globals \
+	-mbulk-memory -mreference-types \
+	-mnontrapping-fptoint -msign-ext \
+	-D_HAVE_SQLITE_CONFIG_H
+
+if which wasm-opt; then
+	wasm-opt -g -O -o speedtest1.tmp speedtest1.wasm
+	mv speedtest1.tmp speedtest1.wasm
+fi

tests/speedtest1/testdata/main.c

@@ -0,0 +1,20 @@
+#include <stdbool.h>
+#include <stddef.h>
+
+#include "sqlite3.c"
+//
+#include "os.c"
+#include "qsort.c"
+#include "time.c"
+
+sqlite3_destructor_type malloc_destructor = &free;
+size_t sqlite3_interrupt_offset = offsetof(sqlite3, u1.isInterrupted);
+
+int sqlite3_os_init() {
+  return sqlite3_vfs_register(os_vfs(), /*default=*/true);
+}
+
+__attribute__((constructor)) void premain() { sqlite3_initialize(); }
+
+#define randomFunc(args...) randomFunc2(args)
+#include "speedtest1.c"

tests/speedtest1/testdata/speedtest1.wasm

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:996c2445ad12c91dce1a59ab5929cfaa3a09a4ac82859fecc7de5e5f9c955f80
+size 1001607

tests/stmt_test.go

@@ -22,7 +22,7 @@ func TestStmt(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	stmt, _, err := db.Prepare(`INSERT INTO test(col) VALUES(?)`)
+	stmt, _, err := db.Prepare(`INSERT INTO test VALUES (?)`)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -400,7 +400,7 @@ func TestStmt_BindName(t *testing.T) {
 	}
 }
 
-func TestStmt_Time(t *testing.T) {
+func TestStmt_ColumnTime(t *testing.T) {
 	t.Parallel()
 
 	db, err := sqlite3.Open(":memory:")
@@ -430,23 +430,23 @@ func TestStmt_Time(t *testing.T) {
 	}
 
 	if now := time.Now(); stmt.Step() {
-		if got := stmt.ColumnTime(0, sqlite3.TimeFormatAuto); !reference.Equal(got) {
+		if got := stmt.ColumnTime(0, sqlite3.TimeFormatAuto); !got.Equal(reference) {
 			t.Errorf("got %v, want %v", got, reference)
 		}
-		if got := stmt.ColumnTime(1, sqlite3.TimeFormatAuto); !reference.Equal(got) {
+		if got := stmt.ColumnTime(1, sqlite3.TimeFormatAuto); !got.Equal(reference) {
 			t.Errorf("got %v, want %v", got, reference)
 		}
-		if got := stmt.ColumnTime(2, sqlite3.TimeFormatAuto); reference.Sub(got) > time.Millisecond {
+		if got := stmt.ColumnTime(2, sqlite3.TimeFormatAuto); got.Sub(reference).Abs() > time.Millisecond {
 			t.Errorf("got %v, want %v", got, reference)
 		}
 
-		if got := stmt.ColumnTime(3, sqlite3.TimeFormatAuto); now.Sub(got) > time.Second {
+		if got := stmt.ColumnTime(3, sqlite3.TimeFormatAuto); got.Sub(now).Abs() > time.Second {
 			t.Errorf("got %v, want %v", got, now)
 		}
-		if got := stmt.ColumnTime(4, sqlite3.TimeFormatAuto); now.Sub(got) > time.Second {
+		if got := stmt.ColumnTime(4, sqlite3.TimeFormatAuto); got.Sub(now).Abs() > time.Second {
 			t.Errorf("got %v, want %v", got, now)
 		}
-		if got := stmt.ColumnTime(5, sqlite3.TimeFormatAuto); now.Sub(got) > time.Millisecond {
+		if got := stmt.ColumnTime(5, sqlite3.TimeFormatAuto); got.Sub(now).Abs() > time.Second/10 {
 			t.Errorf("got %v, want %v", got, now)
 		}
 

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

@@ -0,0 +1,535 @@
+package tests
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+)
+
+func TestConn_Transaction_exec(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)
+	}
+
+	errFailed := errors.New("failed")
+
+	count := func() int {
+		stmt, _, err := db.Prepare(`SELECT count(*) FROM test`)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer stmt.Close()
+		if stmt.Step() {
+			return stmt.ColumnInt(0)
+		}
+		t.Fatal(stmt.Err())
+		return 0
+	}
+
+	insert := func(succeed bool) (err error) {
+		tx := db.Begin()
+		defer tx.End(&err)
+
+		err = db.Exec(`INSERT INTO test VALUES ('hello')`)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if succeed {
+			return nil
+		}
+		return errFailed
+	}
+
+	err = insert(true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := count(); got != 1 {
+		t.Errorf("got %d, want 1", got)
+	}
+
+	err = insert(true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := count(); got != 2 {
+		t.Errorf("got %d, want 2", got)
+	}
+
+	err = insert(false)
+	if err != errFailed {
+		t.Errorf("got %v, want errFailed", err)
+	}
+	if got := count(); got != 2 {
+		t.Errorf("got %d, want 2", got)
+	}
+}
+
+func TestConn_Transaction_panic(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 ('one');`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	panics := func() (err error) {
+		tx := db.Begin()
+		defer tx.End(&err)
+
+		err = db.Exec(`INSERT INTO test VALUES ('hello')`)
+		if err != nil {
+			return err
+		}
+
+		panic("omg!")
+	}
+
+	defer func() {
+		p := recover()
+		if p != "omg!" {
+			t.Errorf("got %v, want panic", p)
+		}
+
+		stmt, _, err := db.Prepare(`SELECT count(*) FROM test`)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer stmt.Close()
+		if stmt.Step() {
+			got := stmt.ColumnInt(0)
+			if got != 1 {
+				t.Errorf("got %d, want 1", got)
+			}
+			return
+		}
+		t.Fatal(stmt.Err())
+	}()
+
+	err = panics()
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func TestConn_Transaction_interrupt(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)
+	}
+
+	tx, err := db.BeginImmediate()
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = db.Exec(`INSERT INTO test VALUES (1)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	tx.End(&err)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	db.SetInterrupt(ctx)
+
+	tx, err = db.BeginExclusive()
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = db.Exec(`INSERT INTO test VALUES (2)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cancel()
+	_, err = db.BeginImmediate()
+	if !errors.Is(err, sqlite3.INTERRUPT) {
+		t.Errorf("got %v, want sqlite3.INTERRUPT", err)
+	}
+
+	err = db.Exec(`INSERT INTO test VALUES (3)`)
+	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)
+	}
+
+	db.SetInterrupt(context.Background())
+	stmt, _, err := db.Prepare(`SELECT count(*) FROM test`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stmt.Close()
+
+	if stmt.Step() {
+		got := stmt.ColumnInt(0)
+		if got != 1 {
+			t.Errorf("got %d, want 1", got)
+		}
+	}
+	err = stmt.Err()
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+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()
+
+	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)
+	}
+
+	tx := db.Begin()
+	err = db.Exec(`INSERT INTO test VALUES (1)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = db.Exec(`COMMIT`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	tx.End(&err)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	stmt, _, err := db.Prepare(`SELECT count(*) FROM test`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stmt.Close()
+
+	if stmt.Step() {
+		got := stmt.ColumnInt(0)
+		if got != 1 {
+			t.Errorf("got %d, want 1", got)
+		}
+	}
+	err = stmt.Err()
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func TestConn_Savepoint_exec(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)
+	}
+
+	errFailed := errors.New("failed")
+
+	count := func() int {
+		stmt, _, err := db.Prepare(`SELECT count(*) FROM test`)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer stmt.Close()
+		if stmt.Step() {
+			return stmt.ColumnInt(0)
+		}
+		t.Fatal(stmt.Err())
+		return 0
+	}
+
+	insert := func(succeed bool) (err error) {
+		defer db.Savepoint().Release(&err)
+
+		err = db.Exec(`INSERT INTO test VALUES ('hello')`)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if succeed {
+			return nil
+		}
+		return errFailed
+	}
+
+	err = insert(true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := count(); got != 1 {
+		t.Errorf("got %d, want 1", got)
+	}
+
+	err = insert(true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := count(); got != 2 {
+		t.Errorf("got %d, want 2", got)
+	}
+
+	err = insert(false)
+	if err != errFailed {
+		t.Errorf("got %v, want errFailed", err)
+	}
+	if got := count(); got != 2 {
+		t.Errorf("got %d, want 2", got)
+	}
+}
+
+func TestConn_Savepoint_panic(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 ('one');`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	panics := func() (err error) {
+		defer db.Savepoint().Release(&err)
+
+		err = db.Exec(`INSERT INTO test VALUES ('hello')`)
+		if err != nil {
+			return err
+		}
+
+		panic("omg!")
+	}
+
+	defer func() {
+		p := recover()
+		if p != "omg!" {
+			t.Errorf("got %v, want panic", p)
+		}
+
+		stmt, _, err := db.Prepare(`SELECT count(*) FROM test`)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer stmt.Close()
+		if stmt.Step() {
+			got := stmt.ColumnInt(0)
+			if got != 1 {
+				t.Errorf("got %d, want 1", got)
+			}
+			return
+		}
+		t.Fatal(stmt.Err())
+	}()
+
+	err = panics()
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func TestConn_Savepoint_interrupt(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)
+	}
+
+	savept := db.Savepoint()
+	err = db.Exec(`INSERT INTO test VALUES (1)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	savept.Release(&err)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	db.SetInterrupt(ctx)
+
+	savept1 := db.Savepoint()
+	err = db.Exec(`INSERT INTO test VALUES (2)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	savept2 := db.Savepoint()
+	err = db.Exec(`INSERT INTO test VALUES (3)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cancel()
+	db.Savepoint().Release(&err)
+	if !errors.Is(err, sqlite3.INTERRUPT) {
+		t.Errorf("got %v, want sqlite3.INTERRUPT", err)
+	}
+
+	err = db.Exec(`INSERT INTO test VALUES (4)`)
+	if !errors.Is(err, sqlite3.INTERRUPT) {
+		t.Errorf("got %v, want sqlite3.INTERRUPT", err)
+	}
+
+	err = context.Canceled
+	savept2.Release(&err)
+	if err != context.Canceled {
+		t.Fatal(err)
+	}
+
+	err = nil
+	savept1.Release(&err)
+	if !errors.Is(err, sqlite3.INTERRUPT) {
+		t.Errorf("got %v, want sqlite3.INTERRUPT", err)
+	}
+
+	db.SetInterrupt(context.Background())
+	stmt, _, err := db.Prepare(`SELECT count(*) FROM test`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stmt.Close()
+
+	if stmt.Step() {
+		got := stmt.ColumnInt(0)
+		if got != 1 {
+			t.Errorf("got %d, want 1", got)
+		}
+	}
+	err = stmt.Err()
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func TestConn_Savepoint_rollback(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)
+	}
+
+	savept := db.Savepoint()
+	err = db.Exec(`INSERT INTO test VALUES (1)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = db.Exec(`COMMIT`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	savept.Release(&err)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	stmt, _, err := db.Prepare(`SELECT count(*) FROM test`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stmt.Close()
+
+	if stmt.Step() {
+		got := stmt.ColumnInt(0)
+		if got != 1 {
+			t.Errorf("got %d, want 1", got)
+		}
+	}
+	err = stmt.Err()
+	if err != nil {
+		t.Error(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

@@ -11,6 +11,9 @@ import (
 
 // TimeFormat specifies how to encode/decode time values.
 //
+// See the documentation for the [TimeFormatDefault] constant
+// for formats recognized by SQLite.
+//
 // https://www.sqlite.org/lang_datefunc.html
 type TimeFormat string
 
@@ -57,12 +60,31 @@ const (
 // Encode encodes a time value using this format.
 //
 // [TimeFormatDefault] and [TimeFormatAuto] encode using [time.RFC3339Nano],
-// with nanosecond accuracy, and preserving timezone.
+// with nanosecond accuracy, and preserving any timezone offset.
 //
-// Formats that don't record the timezone
+// 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.
+//
+// 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.
 //
+// Returns a string for the text formats,
+// a float64 for [TimeFormatJulianDay] and [TimeFormatUnixFrac],
+// 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
@@ -81,11 +103,13 @@ func (f TimeFormat) Encode(t time.Time) any {
 	// Special formats
 	case TimeFormatDefault, TimeFormatAuto:
 		f = time.RFC3339Nano
-	}
 	// SQLite assumes UTC if unspecified.
-	if !strings.Contains(string(f), "MST") &&
-		!strings.Contains(string(f), "Z07") &&
-		!strings.Contains(string(f), "-07") {
+	case
+		TimeFormat1, TimeFormat2,
+		TimeFormat3, TimeFormat4,
+		TimeFormat5, TimeFormat6,
+		TimeFormat7, TimeFormat8,
+		TimeFormat9, TimeFormat10:
 		t = t.UTC()
 	}
 	return t.Format(string(f))
@@ -93,8 +117,23 @@ func (f TimeFormat) Encode(t time.Time) any {
 
 // Decode decodes a time value using this format.
 //
-// Decoding of SQLite recognized formats is lenient:
-// timezones and fractional seconds are always optional.
+// The time value can be a string, an int64, or a float64.
+//
+// Formats [TimeFormat8] through [TimeFormat10]
+// (and [TimeFormat8TZ] through [TimeFormat10TZ])
+// assume a date of 2000-01-01.
+//
+// The timezone indicator and fractional seconds are always optional
+// for formats [TimeFormat2] through [TimeFormat10]
+// (and [TimeFormat2TZ] through [TimeFormat10TZ]).
+//
+// [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 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
 func (f TimeFormat) Decode(v any) (time.Time, error) {
@@ -263,14 +302,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		if !ok {
 			return time.Time{}, timeErr
 		}
-		f := string(f)
-		f = strings.TrimSuffix(f, "Z07:00")
-		f = strings.TrimSuffix(f, ".000")
-		t, err := time.Parse(f+"Z07:00", s)
-		if err != nil {
-			t, err = time.Parse(f, s)
-		}
-		return t, err
+		return f.parseRelaxed(s)
 
 	case
 		TimeFormat8, TimeFormat8TZ,
@@ -280,13 +312,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		if !ok {
 			return time.Time{}, timeErr
 		}
-		f := string(f)
-		f = strings.TrimSuffix(f, "Z07:00")
-		f = strings.TrimSuffix(f, ".000")
-		t, err := time.Parse(f+"Z07:00", s)
-		if err != nil {
-			t, err = time.Parse(f, s)
-		}
+		t, err := f.parseRelaxed(s)
 		return t.AddDate(2000, 0, 0), err
 
 	default:
@@ -294,10 +320,20 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		if !ok {
 			return time.Time{}, timeErr
 		}
-		f := string(f)
 		if f == "" {
 			f = time.RFC3339Nano
 		}
-		return time.Parse(f, s)
+		return time.Parse(string(f), s)
 	}
 }
+
+func (f TimeFormat) parseRelaxed(s string) (time.Time, error) {
+	fs := string(f)
+	fs = strings.TrimSuffix(fs, "Z07:00")
+	fs = strings.TrimSuffix(fs, ".000")
+	t, err := time.Parse(fs+"Z07:00", s)
+	if err != nil {
+		return time.Parse(fs, s)
+	}
+	return t, nil
+}

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

@@ -0,0 +1,202 @@
+package sqlite3
+
+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
+}
+
+// Begin starts a deferred transaction.
+//
+// https://www.sqlite.org/lang_transaction.html
+func (c *Conn) Begin() Tx {
+	// BEGIN even if interrupted.
+	err := c.txExecInterrupted(`BEGIN DEFERRED`)
+	if err != nil {
+		panic(err)
+	}
+	return Tx{c}
+}
+
+// BeginImmediate starts an immediate transaction.
+//
+// https://www.sqlite.org/lang_transaction.html
+func (c *Conn) BeginImmediate() (Tx, error) {
+	err := c.Exec(`BEGIN IMMEDIATE`)
+	if err != nil {
+		return Tx{}, err
+	}
+	return Tx{c}, nil
+}
+
+// BeginExclusive starts an exclusive transaction.
+//
+// https://www.sqlite.org/lang_transaction.html
+func (c *Conn) BeginExclusive() (Tx, error) {
+	err := c.Exec(`BEGIN EXCLUSIVE`)
+	if err != nil {
+		return Tx{}, err
+	}
+	return Tx{c}, nil
+}
+
+// End calls either [Tx.Commit] or [Tx.Rollback]
+// depending on whether *error points to a nil or non-nil error.
+//
+// This is meant to be deferred:
+//
+//	func doWork(conn *sqlite3.Conn) (err error) {
+//		tx := conn.Begin()
+//		defer tx.End(&err)
+//
+//		// ... do work in the transaction
+//	}
+//
+// https://www.sqlite.org/lang_transaction.html
+func (tx Tx) End(errp *error) {
+	recovered := recover()
+	if recovered != nil {
+		defer panic(recovered)
+	}
+
+	if (errp == nil || *errp == nil) && recovered == nil {
+		// Success path.
+		if tx.c.GetAutocommit() { // There is nothing to commit.
+			return
+		}
+		*errp = tx.Commit()
+		if *errp == nil {
+			return
+		}
+		// 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)
+	}
+}
+
+// Commit commits the transaction.
+//
+// https://www.sqlite.org/lang_transaction.html
+func (tx Tx) Commit() error {
+	return tx.c.Exec(`COMMIT`)
+}
+
+// Rollback rolls back the transaction,
+// even if the connection has been interrupted.
+//
+// https://www.sqlite.org/lang_transaction.html
+func (tx Tx) Rollback() error {
+	return tx.c.txExecInterrupted(`ROLLBACK`)
+}
+
+// Savepoint is a marker within a transaction
+// that allows for partial rollback.
+//
+// https://www.sqlite.org/lang_savepoint.html
+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])
+		frame, _ := frames.Next()
+		if frame.Function != "" {
+			name = frame.Function
+		}
+	}
+	// Names can be reused; this makes catching bugs more likely.
+	name += "#" + strconv.Itoa(int(rand.Int31()))
+
+	err := c.txExecInterrupted(fmt.Sprintf("SAVEPOINT %q;", name))
+	if err != nil {
+		panic(err)
+	}
+	return Savepoint{c: c, name: name}
+}
+
+// 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 (errp == nil || *errp == nil) && recovered == nil {
+		// Success path.
+		if s.c.GetAutocommit() { // There is nothing to commit.
+			return
+		}
+		*errp = s.c.Exec(fmt.Sprintf("RELEASE %q;", s.name))
+		if *errp == nil {
+			return
+		}
+		// Fall through to the error path.
+	}
+
+	// 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
+}

util.go

@@ -1,16 +0,0 @@
-package sqlite3
-
-// Return true if stmt is an empty SQL statement.
-// This is used as an optimization.
-// It's OK to always return false here.
-func emptyStatement(stmt string) bool {
-	for _, b := range []byte(stmt) {
-		switch b {
-		case ' ', '\n', '\r', '\t', '\v', '\f':
-		case ';':
-		default:
-			return false
-		}
-	}
-	return true
-}

vfs.go

@@ -9,7 +9,6 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
-	"syscall"
 	"time"
 
 	"github.com/ncruces/julianday"
@@ -26,32 +25,68 @@ func vfsInstantiate(ctx context.Context, r wazero.Runtime) {
 		panic(err)
 	}
 
-	env := r.NewHostModuleBuilder("env")
-	env.NewFunctionBuilder().WithFunc(vfsLocaltime).Export("go_localtime")
-	env.NewFunctionBuilder().WithFunc(vfsRandomness).Export("go_randomness")
-	env.NewFunctionBuilder().WithFunc(vfsSleep).Export("go_sleep")
-	env.NewFunctionBuilder().WithFunc(vfsCurrentTime).Export("go_current_time")
-	env.NewFunctionBuilder().WithFunc(vfsCurrentTime64).Export("go_current_time_64")
-	env.NewFunctionBuilder().WithFunc(vfsFullPathname).Export("go_full_pathname")
-	env.NewFunctionBuilder().WithFunc(vfsDelete).Export("go_delete")
-	env.NewFunctionBuilder().WithFunc(vfsAccess).Export("go_access")
-	env.NewFunctionBuilder().WithFunc(vfsOpen).Export("go_open")
-	env.NewFunctionBuilder().WithFunc(vfsClose).Export("go_close")
-	env.NewFunctionBuilder().WithFunc(vfsRead).Export("go_read")
-	env.NewFunctionBuilder().WithFunc(vfsWrite).Export("go_write")
-	env.NewFunctionBuilder().WithFunc(vfsTruncate).Export("go_truncate")
-	env.NewFunctionBuilder().WithFunc(vfsSync).Export("go_sync")
-	env.NewFunctionBuilder().WithFunc(vfsFileSize).Export("go_file_size")
-	env.NewFunctionBuilder().WithFunc(vfsLock).Export("go_lock")
-	env.NewFunctionBuilder().WithFunc(vfsUnlock).Export("go_unlock")
-	env.NewFunctionBuilder().WithFunc(vfsCheckReservedLock).Export("go_check_reserved_lock")
-	env.NewFunctionBuilder().WithFunc(vfsFileControl).Export("go_file_control")
+	env := vfsNewEnvModuleBuilder(r)
 	_, err = env.Instantiate(ctx)
 	if err != nil {
 		panic(err)
 	}
 }
 
+func vfsNewEnvModuleBuilder(r wazero.Runtime) wazero.HostModuleBuilder {
+	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")
+	return env
+}
+
+// Poor man's namespaces.
+const (
+	vfsOS   vfsOSMethods   = false
+	vfsFile vfsFileMethods = false
+)
+
+type (
+	vfsOSMethods   bool
+	vfsFileMethods bool
+)
+
+type vfsKey struct{}
+type vfsState struct {
+	files []*os.File
+}
+
+func vfsContext(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 vfsExit(ctx context.Context, mod api.Module, exitCode uint32) {
 	// Ensure other callers see the exit code.
 	_ = mod.CloseWithExitCode(ctx, exitCode)
@@ -81,7 +116,7 @@ func vfsLocaltime(ctx context.Context, mod api.Module, t uint64, pTm uint32) uin
 }
 
 func vfsRandomness(ctx context.Context, mod api.Module, pVfs, nByte, zByte uint32) uint32 {
-	mem := memory{mod}.view(zByte, nByte)
+	mem := memory{mod}.view(zByte, uint64(nByte))
 	n, _ := rand.Reader.Read(mem)
 	return uint32(n)
 }
@@ -108,88 +143,83 @@ func vfsFullPathname(ctx context.Context, mod api.Module, pVfs, zRelative, nFull
 	rel := memory{mod}.readString(zRelative, _MAX_PATHNAME)
 	abs, err := filepath.Abs(rel)
 	if err != nil {
-		return uint32(IOERR)
+		return uint32(CANTOPEN_FULLPATH)
 	}
 
 	// 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 := uint32(len(abs) + 1)
-	if size > nFull {
+	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
+
+	if fi, err := os.Lstat(abs); err == nil {
+		if fi.Mode()&fs.ModeSymlink != 0 {
+			return _OK_SYMLINK
+		}
+		return _OK
+	} else if errors.Is(err, fs.ErrNotExist) {
+		return _OK
+	}
+	return uint32(CANTOPEN_FULLPATH)
 }
 
 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
+		return uint32(IOERR_DELETE_NOENT)
 	}
 	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
+		}
+		defer f.Close()
+		err = vfsOS.Sync(f, false, false)
+		if err != nil {
+			return uint32(IOERR_DIR_FSYNC)
 		}
 	}
 	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)
+	err := vfsOS.Access(path, flags)
 
 	var res uint32
-	switch {
-	case flags == _ACCESS_EXISTS:
+	var rc xErrorCode
+	if flags == _ACCESS_EXISTS {
 		switch {
 		case err == nil:
 			res = 1
 		case errors.Is(err, fs.ErrNotExist):
 			res = 0
 		default:
-			return uint32(IOERR_ACCESS)
+			rc = 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 {
+	} else {
+		switch {
+		case err == nil:
 			res = 1
-		} else {
+		case errors.Is(err, fs.ErrPermission):
 			res = 0
+		default:
+			rc = IOERR_ACCESS
 		}
-
-	case errors.Is(err, fs.ErrPermission):
-		res = 0
-
-	default:
-		return uint32(IOERR_ACCESS)
 	}
 
 	memory{mod}.writeUint32(pResOut, res)
-	return _OK
+	return uint32(rc)
 }
 
 func vfsOpen(ctx context.Context, mod api.Module, pVfs, zName, pFile uint32, flags OpenFlag, pOutFlags uint32) uint32 {
@@ -213,25 +243,17 @@ func vfsOpen(ctx context.Context, mod api.Module, pVfs, zName, pFile uint32, fla
 		file, err = os.CreateTemp("", "*.db")
 	} else {
 		name := memory{mod}.readString(zName, _MAX_PATHNAME)
-		file, err = os.OpenFile(name, oflags, 0600)
+		file, err = vfsOS.OpenFile(name, oflags, 0600)
 	}
 	if err != nil {
 		return uint32(CANTOPEN)
 	}
 
 	if flags&OPEN_DELETEONCLOSE != 0 {
-		deleteOnClose(file)
+		os.Remove(file.Name())
 	}
 
-	info, err := file.Stat()
-	if err != nil {
-		return uint32(CANTOPEN)
-	}
-	if info.IsDir() {
-		return uint32(CANTOPEN_ISDIR)
-	}
-	id := vfsGetOpenFileID(file, info)
-	vfsFilePtr{mod, pFile}.SetID(id).SetLock(_NO_LOCK)
+	vfsFile.Open(ctx, mod, pFile, file)
 
 	if pOutFlags != 0 {
 		memory{mod}.writeUint32(pOutFlags, uint32(flags))
@@ -240,8 +262,7 @@ func vfsOpen(ctx context.Context, mod api.Module, pVfs, zName, pFile uint32, fla
 }
 
 func vfsClose(ctx context.Context, mod api.Module, pFile uint32) uint32 {
-	id := vfsFilePtr{mod, pFile}.ID()
-	err := vfsReleaseOpenFile(id)
+	err := vfsFile.Close(ctx, mod, pFile)
 	if err != nil {
 		return uint32(IOERR_CLOSE)
 	}
@@ -249,9 +270,9 @@ func vfsClose(ctx context.Context, mod api.Module, pFile uint32) uint32 {
 }
 
 func vfsRead(ctx context.Context, mod api.Module, pFile, zBuf, iAmt uint32, iOfst uint64) uint32 {
-	buf := memory{mod}.view(zBuf, iAmt)
+	buf := memory{mod}.view(zBuf, uint64(iAmt))
 
-	file := vfsFilePtr{mod, pFile}.OSFile()
+	file := vfsFile.GetOS(ctx, mod, pFile)
 	n, err := file.ReadAt(buf, int64(iOfst))
 	if n == int(iAmt) {
 		return _OK
@@ -266,9 +287,9 @@ func vfsRead(ctx context.Context, mod api.Module, pFile, zBuf, iAmt uint32, iOfs
 }
 
 func vfsWrite(ctx context.Context, mod api.Module, pFile, zBuf, iAmt uint32, iOfst uint64) uint32 {
-	buf := memory{mod}.view(zBuf, iAmt)
+	buf := memory{mod}.view(zBuf, uint64(iAmt))
 
-	file := vfsFilePtr{mod, pFile}.OSFile()
+	file := vfsFile.GetOS(ctx, mod, pFile)
 	_, err := file.WriteAt(buf, int64(iOfst))
 	if err != nil {
 		return uint32(IOERR_WRITE)
@@ -277,7 +298,7 @@ func vfsWrite(ctx context.Context, mod api.Module, pFile, zBuf, iAmt uint32, iOf
 }
 
 func vfsTruncate(ctx context.Context, mod api.Module, pFile uint32, nByte uint64) uint32 {
-	file := vfsFilePtr{mod, pFile}.OSFile()
+	file := vfsFile.GetOS(ctx, mod, pFile)
 	err := file.Truncate(int64(nByte))
 	if err != nil {
 		return uint32(IOERR_TRUNCATE)
@@ -285,9 +306,11 @@ func vfsTruncate(ctx context.Context, mod api.Module, pFile uint32, nByte uint64
 	return _OK
 }
 
-func vfsSync(ctx context.Context, mod api.Module, pFile, flags uint32) uint32 {
-	file := vfsFilePtr{mod, pFile}.OSFile()
-	err := file.Sync()
+func vfsSync(ctx context.Context, mod api.Module, pFile uint32, flags _SyncFlag) uint32 {
+	dataonly := (flags & _SYNC_DATAONLY) != 0
+	fullsync := (flags & 0x0f) == _SYNC_FULL
+	file := vfsFile.GetOS(ctx, mod, pFile)
+	err := vfsOS.Sync(file, fullsync, dataonly)
 	if err != nil {
 		return uint32(IOERR_FSYNC)
 	}
@@ -295,10 +318,7 @@ func vfsSync(ctx context.Context, mod api.Module, pFile, flags uint32) uint32 {
 }
 
 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()
+	file := vfsFile.GetOS(ctx, mod, pFile)
 	off, err := file.Seek(0, io.SeekEnd)
 	if err != nil {
 		return uint32(IOERR_SEEK)
@@ -308,14 +328,43 @@ func vfsFileSize(ctx context.Context, mod api.Module, pFile, pSize uint32) uint3
 	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
+func vfsFileControl(ctx context.Context, mod api.Module, pFile uint32, op _FcntlOpcode, pArg uint32) uint32 {
+	switch op {
+	case _FCNTL_SIZE_HINT:
+		return vfsSizeHint(ctx, mod, pFile, pArg)
+	case _FCNTL_HAS_MOVED:
+		return vfsFileMoved(ctx, mod, pFile, pArg)
+	}
 	return uint32(NOTFOUND)
 }
+
+func vfsSizeHint(ctx context.Context, mod api.Module, pFile, pArg uint32) uint32 {
+	file := vfsFile.GetOS(ctx, mod, pFile)
+	size := memory{mod}.readUint64(pArg)
+	err := vfsOS.Allocate(file, int64(size))
+	if err == notImplErr {
+		return uint32(NOTFOUND)
+	}
+	if err != nil {
+		return uint32(IOERR_TRUNCATE)
+	}
+	return _OK
+}
+
+func vfsFileMoved(ctx context.Context, mod api.Module, pFile, pResOut uint32) uint32 {
+	file := vfsFile.GetOS(ctx, mod, pFile)
+	fi, err := file.Stat()
+	if err != nil {
+		return uint32(IOERR_FSTAT)
+	}
+	pi, err := os.Stat(file.Name())
+	if err != nil && !errors.Is(err, fs.ErrNotExist) {
+		return uint32(IOERR_FSTAT)
+	}
+	var res uint32
+	if !os.SameFile(fi, pi) {
+		res = 1
+	}
+	memory{mod}.writeUint32(pResOut, res)
+	return _OK
+}

vfs_file.go

@@ -0,0 +1,69 @@
+package sqlite3
+
+import (
+	"context"
+	"os"
+	"time"
+
+	"github.com/tetratelabs/wazero/api"
+)
+
+const (
+	// These need to match the offsets asserted in os.c
+	vfsFileIDOffset          = 4
+	vfsFileLockOffset        = 8
+	vfsFileLockTimeoutOffset = 12
+)
+
+func (vfsFileMethods) NewID(ctx context.Context, file *os.File) uint32 {
+	vfs := ctx.Value(vfsKey{}).(*vfsState)
+
+	// Find an empty slot.
+	for id, ptr := range vfs.files {
+		if ptr == 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 (vfsFileMethods) Open(ctx context.Context, mod api.Module, pFile uint32, file *os.File) {
+	mem := memory{mod}
+	id := vfsFile.NewID(ctx, file)
+	mem.writeUint32(pFile+vfsFileIDOffset, id)
+}
+
+func (vfsFileMethods) Close(ctx context.Context, mod api.Module, pFile uint32) error {
+	mem := memory{mod}
+	id := mem.readUint32(pFile + vfsFileIDOffset)
+	vfs := ctx.Value(vfsKey{}).(*vfsState)
+	file := vfs.files[id]
+	vfs.files[id] = nil
+	return file.Close()
+}
+
+func (vfsFileMethods) GetOS(ctx context.Context, mod api.Module, pFile uint32) *os.File {
+	mem := memory{mod}
+	id := mem.readUint32(pFile + vfsFileIDOffset)
+	vfs := ctx.Value(vfsKey{}).(*vfsState)
+	return vfs.files[id]
+}
+
+func (vfsFileMethods) GetLock(ctx context.Context, mod api.Module, pFile uint32) vfsLockState {
+	mem := memory{mod}
+	return vfsLockState(mem.readUint8(pFile + vfsFileLockOffset))
+}
+
+func (vfsFileMethods) SetLock(ctx context.Context, mod api.Module, pFile uint32, lock vfsLockState) {
+	mem := memory{mod}
+	mem.writeUint8(pFile+vfsFileLockOffset, uint8(lock))
+}
+
+func (vfsFileMethods) GetLockTimeout(ctx context.Context, mod api.Module, pFile uint32) time.Duration {
+	mem := memory{mod}
+	return time.Duration(mem.readUint32(pFile+vfsFileLockTimeoutOffset)) * time.Millisecond
+}

vfs_files.go

@@ -1,107 +0,0 @@
-package sqlite3
-
-import (
-	"os"
-	"sync"
-
-	"github.com/tetratelabs/wazero/api"
-)
-
-type vfsOpenFile struct {
-	file   *os.File
-	info   os.FileInfo
-	nref   int
-	locker vfsFileLocker
-}
-
-var (
-	vfsOpenFiles    []*vfsOpenFile
-	vfsOpenFilesMtx sync.Mutex
-)
-
-func vfsGetOpenFileID(file *os.File, info os.FileInfo) uint32 {
-	vfsOpenFilesMtx.Lock()
-	defer vfsOpenFilesMtx.Unlock()
-
-	// Reuse an already opened file.
-	for id, of := range vfsOpenFiles {
-		if of == nil {
-			continue
-		}
-		if os.SameFile(info, of.info) {
-			of.nref++
-			_ = file.Close()
-			return uint32(id)
-		}
-	}
-
-	of := &vfsOpenFile{
-		file:   file,
-		info:   info,
-		nref:   1,
-		locker: vfsFileLocker{file: file},
-	}
-
-	// Find an empty slot.
-	for id, ptr := range vfsOpenFiles {
-		if ptr == nil {
-			vfsOpenFiles[id] = of
-			return uint32(id)
-		}
-	}
-
-	// Add a new slot.
-	id := len(vfsOpenFiles)
-	vfsOpenFiles = append(vfsOpenFiles, of)
-	return uint32(id)
-}
-
-func vfsReleaseOpenFile(id uint32) error {
-	vfsOpenFilesMtx.Lock()
-	defer vfsOpenFilesMtx.Unlock()
-
-	of := vfsOpenFiles[id]
-	if of.nref--; of.nref > 0 {
-		return nil
-	}
-	err := of.file.Close()
-	vfsOpenFiles[id] = nil
-	return err
-}
-
-type vfsFilePtr struct {
-	api.Module
-	ptr uint32
-}
-
-func (p vfsFilePtr) OSFile() *os.File {
-	id := p.ID()
-	vfsOpenFilesMtx.Lock()
-	defer vfsOpenFilesMtx.Unlock()
-	return vfsOpenFiles[id].file
-}
-
-func (p vfsFilePtr) Locker() *vfsFileLocker {
-	id := p.ID()
-	vfsOpenFilesMtx.Lock()
-	defer vfsOpenFilesMtx.Unlock()
-	return &vfsOpenFiles[id].locker
-}
-
-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

@@ -3,7 +3,7 @@ package sqlite3
 import (
 	"context"
 	"os"
-	"sync"
+	"time"
 
 	"github.com/tetratelabs/wazero/api"
 )
@@ -56,21 +56,15 @@ const (
 
 type vfsLockState uint32
 
-type vfsFileLocker struct {
-	sync.Mutex
-	file   *os.File
-	state  vfsLockState
-	shared int
-}
-
 func vfsLock(ctx context.Context, mod api.Module, pFile uint32, eLock vfsLockState) uint32 {
-	// Argument check. SQLite never explicitly requests a pendig lock.
+	// Argument check. SQLite never explicitly requests a pending lock.
 	if eLock != _SHARED_LOCK && eLock != _RESERVED_LOCK && eLock != _EXCLUSIVE_LOCK {
 		panic(assertErr())
 	}
 
-	ptr := vfsFilePtr{mod, pFile}
-	cLock := ptr.Lock()
+	file := vfsFile.GetOS(ctx, mod, pFile)
+	cLock := vfsFile.GetLock(ctx, mod, pFile)
+	timeout := vfsFile.GetLockTimeout(ctx, mod, pFile)
 
 	switch {
 	case cLock < _NO_LOCK || cLock > _EXCLUSIVE_LOCK:
@@ -89,93 +83,49 @@ func vfsLock(ctx context.Context, mod api.Module, pFile uint32, eLock vfsLockSta
 		return _OK
 	}
 
-	fLock := ptr.Locker()
-	fLock.Lock()
-	defer fLock.Unlock()
-
-	// File state check.
-	switch {
-	case fLock.state < _NO_LOCK || fLock.state > _EXCLUSIVE_LOCK:
-		panic(assertErr())
-	case fLock.state == _NO_LOCK && fLock.shared != 0:
-		panic(assertErr())
-	case fLock.state == _EXCLUSIVE_LOCK && fLock.shared != 1:
-		panic(assertErr())
-	case fLock.state != _NO_LOCK && fLock.shared <= 0:
-		panic(assertErr())
-	case fLock.state < cLock:
-		panic(assertErr())
-	}
-
-	// If some other connection has a lock that precludes the requested lock, return BUSY.
-	if cLock != fLock.state && (eLock > _SHARED_LOCK || fLock.state >= _PENDING_LOCK) {
-		return uint32(BUSY)
-	}
-
 	switch eLock {
 	case _SHARED_LOCK:
-		// Test the PENDING lock before acquiring a new SHARED lock.
-		if locked, _ := fLock.CheckPending(); locked {
-			return uint32(BUSY)
-		}
-
-		// If some other connection has a SHARED or RESERVED lock,
-		// increment the reference count and return OK.
-		if fLock.state == _SHARED_LOCK || fLock.state == _RESERVED_LOCK {
-			ptr.SetLock(_SHARED_LOCK)
-			fLock.shared++
-			return _OK
-		}
-
 		// Must be unlocked to get SHARED.
-		if fLock.state != _NO_LOCK {
+		if cLock != _NO_LOCK {
 			panic(assertErr())
 		}
-		if rc := fLock.GetShared(); rc != _OK {
+		// Test the PENDING lock before acquiring a new SHARED lock.
+		if locked, _ := vfsOS.CheckPendingLock(file); locked {
+			return uint32(BUSY)
+		}
+		if rc := vfsOS.GetSharedLock(file, timeout); rc != _OK {
 			return uint32(rc)
 		}
-		ptr.SetLock(_SHARED_LOCK)
-		fLock.state = _SHARED_LOCK
-		fLock.shared = 1
+		vfsFile.SetLock(ctx, mod, pFile, _SHARED_LOCK)
 		return _OK
 
 	case _RESERVED_LOCK:
 		// Must be SHARED to get RESERVED.
-		if fLock.state != _SHARED_LOCK {
+		if cLock != _SHARED_LOCK {
 			panic(assertErr())
 		}
-		if rc := fLock.GetReserved(); rc != _OK {
+		if rc := vfsOS.GetReservedLock(file, timeout); rc != _OK {
 			return uint32(rc)
 		}
-		ptr.SetLock(_RESERVED_LOCK)
-		fLock.state = _RESERVED_LOCK
+		vfsFile.SetLock(ctx, mod, pFile, _RESERVED_LOCK)
 		return _OK
 
 	case _EXCLUSIVE_LOCK:
-		// Must be SHARED, PENDING or RESERVED to get EXCLUSIVE.
-		if fLock.state <= _NO_LOCK || fLock.state >= _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 fLock.state == _RESERVED_LOCK {
-			if rc := fLock.GetPending(); rc != _OK {
+		if cLock < _PENDING_LOCK {
+			if rc := vfsOS.GetPendingLock(file); rc != _OK {
 				return uint32(rc)
 			}
-			ptr.SetLock(_PENDING_LOCK)
-			fLock.state = _PENDING_LOCK
+			vfsFile.SetLock(ctx, mod, pFile, _PENDING_LOCK)
 		}
-
-		// We are trying for an EXCLUSIVE lock but another connection is still holding a shared lock.
-		if fLock.shared > 1 {
-			return uint32(BUSY)
-		}
-
-		if rc := fLock.GetExclusive(); rc != _OK {
+		if rc := vfsOS.GetExclusiveLock(file, timeout); rc != _OK {
 			return uint32(rc)
 		}
-		ptr.SetLock(_EXCLUSIVE_LOCK)
-		fLock.state = _EXCLUSIVE_LOCK
+		vfsFile.SetLock(ctx, mod, pFile, _EXCLUSIVE_LOCK)
 		return _OK
 
 	default:
@@ -189,8 +139,8 @@ func vfsUnlock(ctx context.Context, mod api.Module, pFile uint32, eLock vfsLockS
 		panic(assertErr())
 	}
 
-	ptr := vfsFilePtr{mod, pFile}
-	cLock := ptr.Lock()
+	file := vfsFile.GetOS(ctx, mod, pFile)
+	cLock := vfsFile.GetLock(ctx, mod, pFile)
 
 	// Connection state check.
 	if cLock < _NO_LOCK || cLock > _EXCLUSIVE_LOCK {
@@ -202,71 +152,28 @@ func vfsUnlock(ctx context.Context, mod api.Module, pFile uint32, eLock vfsLockS
 		return _OK
 	}
 
-	fLock := ptr.Locker()
-	fLock.Lock()
-	defer fLock.Unlock()
-
-	// File state check.
-	switch {
-	case fLock.state <= _NO_LOCK || fLock.state > _EXCLUSIVE_LOCK:
-		panic(assertErr())
-	case fLock.state == _EXCLUSIVE_LOCK && fLock.shared != 1:
-		panic(assertErr())
-	case fLock.shared <= 0:
-		panic(assertErr())
-	case fLock.state < cLock:
-		panic(assertErr())
-	}
-
-	if cLock > _SHARED_LOCK {
-		// The connection must own the lock to release it.
-		if cLock != fLock.state {
-			panic(assertErr())
+	switch eLock {
+	case _SHARED_LOCK:
+		if rc := vfsOS.DowngradeLock(file, cLock); rc != _OK {
+			return uint32(rc)
 		}
-		if eLock == _SHARED_LOCK {
-			if rc := fLock.Downgrade(); rc != _OK {
-				return uint32(rc)
-			}
-			ptr.SetLock(_SHARED_LOCK)
-			fLock.state = _SHARED_LOCK
-			return _OK
-		}
-	}
+		vfsFile.SetLock(ctx, mod, pFile, _SHARED_LOCK)
+		return _OK
 
-	// If we get here, make sure we're dropping all locks.
-	if eLock != _NO_LOCK {
-		panic(assertErr())
-	}
-
-	// Release the connection lock and decrement the shared lock counter.
-	// Release the file lock only when all connections have released the lock.
-	ptr.SetLock(_NO_LOCK)
-	if fLock.shared--; fLock.shared == 0 {
-		rc := fLock.Release()
-		fLock.state = _NO_LOCK
+	case _NO_LOCK:
+		rc := vfsOS.ReleaseLock(file, cLock)
+		vfsFile.SetLock(ctx, mod, pFile, _NO_LOCK)
 		return uint32(rc)
+
+	default:
+		panic(assertErr())
 	}
-	return _OK
 }
 
 func vfsCheckReservedLock(ctx context.Context, mod api.Module, pFile, pResOut uint32) uint32 {
-	ptr := vfsFilePtr{mod, pFile}
-	cLock := ptr.Lock()
+	file := vfsFile.GetOS(ctx, mod, pFile)
 
-	if cLock > _SHARED_LOCK {
-		panic(assertErr())
-	}
-
-	fLock := ptr.Locker()
-	fLock.Lock()
-	defer fLock.Unlock()
-
-	if fLock.state >= _RESERVED_LOCK {
-		memory{mod}.writeUint32(pResOut, 1)
-		return _OK
-	}
-
-	locked, rc := fLock.CheckReserved()
+	locked, rc := vfsOS.CheckReservedLock(file)
 	var res uint32
 	if locked {
 		res = 1
@@ -274,3 +181,28 @@ func vfsCheckReservedLock(ctx context.Context, mod api.Module, pFile, pResOut ui
 	memory{mod}.writeUint32(pResOut, res)
 	return uint32(rc)
 }
+
+func (vfsOSMethods) GetSharedLock(file *os.File, timeout time.Duration) xErrorCode {
+	// Acquire the SHARED lock.
+	return vfsOS.readLock(file, _SHARED_FIRST, _SHARED_SIZE, timeout)
+}
+
+func (vfsOSMethods) GetReservedLock(file *os.File, timeout time.Duration) xErrorCode {
+	// Acquire the RESERVED lock.
+	return vfsOS.writeLock(file, _RESERVED_BYTE, 1, timeout)
+}
+
+func (vfsOSMethods) GetPendingLock(file *os.File) xErrorCode {
+	// Acquire the PENDING lock.
+	return vfsOS.writeLock(file, _PENDING_BYTE, 1, 0)
+}
+
+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

@@ -9,12 +9,11 @@ import (
 )
 
 func Test_vfsLock(t *testing.T) {
-	// Other OSes lack open file descriptors locks.
 	switch runtime.GOOS {
-	case "linux", "darwin", "illumos", "windows":
-		//
+	case "linux", "darwin", "windows":
+		break
 	default:
-		t.Skip()
+		t.Skip("OS lacks OFD locks")
 	}
 
 	name := filepath.Join(t.TempDir(), "test.db")
@@ -33,28 +32,19 @@ func Test_vfsLock(t *testing.T) {
 	}
 	defer file2.Close()
 
-	// Bypass open file reuse.
-	vfsOpenFiles = append(vfsOpenFiles, &vfsOpenFile{
-		file:   file1,
-		nref:   1,
-		locker: vfsFileLocker{file: file1},
-	}, &vfsOpenFile{
-		file:   file2,
-		nref:   1,
-		locker: vfsFileLocker{file: file2},
-	})
-
-	mem := newMemory(128)
-	mem.writeUint32(4+4, 0)
-	mem.writeUint32(16+4, 1)
-
 	const (
 		pFile1  = 4
 		pFile2  = 16
 		pOutput = 32
 	)
+	mem := newMemory(128)
+	ctx, vfs := vfsContext(context.TODO())
+	defer vfs.Close()
 
-	rc := vfsCheckReservedLock(context.TODO(), mem.mod, pFile1, pOutput)
+	vfsFile.Open(ctx, mem.mod, pFile1, file1)
+	vfsFile.Open(ctx, mem.mod, pFile2, file2)
+
+	rc := vfsCheckReservedLock(ctx, mem.mod, pFile1, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
@@ -62,12 +52,12 @@ func Test_vfsLock(t *testing.T) {
 		t.Error("file was locked")
 	}
 
-	rc = vfsLock(context.TODO(), mem.mod, pFile2, _SHARED_LOCK)
+	rc = vfsLock(ctx, mem.mod, pFile2, _SHARED_LOCK)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
 
-	rc = vfsCheckReservedLock(context.TODO(), mem.mod, pFile1, pOutput)
+	rc = vfsCheckReservedLock(ctx, mem.mod, pFile1, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
@@ -75,16 +65,16 @@ func Test_vfsLock(t *testing.T) {
 		t.Error("file was locked")
 	}
 
-	rc = vfsLock(context.TODO(), mem.mod, pFile2, _RESERVED_LOCK)
+	rc = vfsLock(ctx, mem.mod, pFile2, _RESERVED_LOCK)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	rc = vfsLock(context.TODO(), mem.mod, pFile2, _SHARED_LOCK)
+	rc = vfsLock(ctx, mem.mod, pFile2, _SHARED_LOCK)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
 
-	rc = vfsCheckReservedLock(context.TODO(), mem.mod, pFile1, pOutput)
+	rc = vfsCheckReservedLock(ctx, mem.mod, pFile1, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
@@ -92,12 +82,12 @@ func Test_vfsLock(t *testing.T) {
 		t.Error("file wasn't locked")
 	}
 
-	rc = vfsLock(context.TODO(), mem.mod, pFile2, _EXCLUSIVE_LOCK)
+	rc = vfsLock(ctx, mem.mod, pFile2, _EXCLUSIVE_LOCK)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
 
-	rc = vfsCheckReservedLock(context.TODO(), mem.mod, pFile1, pOutput)
+	rc = vfsCheckReservedLock(ctx, mem.mod, pFile1, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
@@ -105,17 +95,33 @@ func Test_vfsLock(t *testing.T) {
 		t.Error("file wasn't locked")
 	}
 
-	rc = vfsLock(context.TODO(), mem.mod, pFile1, _SHARED_LOCK)
+	rc = vfsLock(ctx, mem.mod, pFile1, _SHARED_LOCK)
 	if rc == _OK {
 		t.Fatal("returned", rc)
 	}
 
-	rc = vfsUnlock(context.TODO(), mem.mod, pFile2, _SHARED_LOCK)
+	rc = vfsCheckReservedLock(ctx, 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(ctx, mem.mod, pFile2, _SHARED_LOCK)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
 
-	rc = vfsLock(context.TODO(), mem.mod, pFile1, _SHARED_LOCK)
+	rc = vfsCheckReservedLock(ctx, 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(ctx, mem.mod, pFile1, _SHARED_LOCK)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}

vfs_os_darwin.go

@@ -0,0 +1,60 @@
+package sqlite3
+
+import (
+	"os"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+func (vfsOSMethods) Sync(file *os.File, fullsync, dataonly bool) error {
+	if !fullsync {
+		return unix.Fsync(int(file.Fd()))
+	}
+	return file.Sync()
+}
+
+func (vfsOSMethods) Allocate(file *os.File, size int64) error {
+	// 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 continous 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
+		return unix.FcntlFstore(file.Fd(), unix.F_PREALLOCATE, &store)
+	}
+	return nil
+}
+
+func (vfsOSMethods) fcntlGetLock(file *os.File, lock *unix.Flock_t) error {
+	const F_OFD_GETLK = 92 // https://github.com/apple/darwin-xnu/blob/main/bsd/sys/fcntl.h
+	return unix.FcntlFlock(file.Fd(), F_OFD_GETLK, lock)
+}
+
+func (vfsOSMethods) fcntlSetLock(file *os.File, lock unix.Flock_t) error {
+	const F_OFD_SETLK = 90 // https://github.com/apple/darwin-xnu/blob/main/bsd/sys/fcntl.h
+	return unix.FcntlFlock(file.Fd(), F_OFD_SETLK, &lock)
+}
+
+func (vfsOSMethods) fcntlSetLockTimeout(file *os.File, lock unix.Flock_t, timeout time.Duration) error {
+	if timeout == 0 {
+		return vfsOS.fcntlSetLock(file, lock)
+	}
+
+	const F_OFD_SETLKWTIMEOUT = 93 // https://github.com/apple/darwin-xnu/blob/main/bsd/sys/fcntl.h
+	flocktimeout := &struct {
+		unix.Flock_t
+		unix.Timespec
+	}{
+		Flock_t:  lock,
+		Timespec: unix.NsecToTimespec(int64(timeout / time.Nanosecond)),
+	}
+	return unix.FcntlFlock(file.Fd(), F_OFD_SETLKWTIMEOUT, &flocktimeout.Flock_t)
+}

vfs_os_linux.go

@@ -0,0 +1,49 @@
+package sqlite3
+
+import (
+	"os"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+func (vfsOSMethods) Sync(file *os.File, fullsync, dataonly bool) error {
+	if dataonly {
+		//lint:ignore SA1019 OK on linux
+		_, _, err := unix.Syscall(unix.SYS_FDATASYNC, file.Fd(), 0, 0)
+		if err != 0 {
+			return err
+		}
+		return nil
+	}
+	return file.Sync()
+}
+
+func (vfsOSMethods) Allocate(file *os.File, size int64) error {
+	if size == 0 {
+		return nil
+	}
+	return unix.Fallocate(int(file.Fd()), 0, 0, size)
+}
+
+func (vfsOSMethods) fcntlGetLock(file *os.File, lock *unix.Flock_t) error {
+	return unix.FcntlFlock(file.Fd(), unix.F_OFD_GETLK, lock)
+}
+
+func (vfsOSMethods) fcntlSetLock(file *os.File, lock unix.Flock_t) error {
+	return unix.FcntlFlock(file.Fd(), unix.F_OFD_SETLK, &lock)
+}
+
+func (vfsOSMethods) fcntlSetLockTimeout(file *os.File, lock unix.Flock_t, timeout time.Duration) error {
+	for {
+		err := unix.FcntlFlock(file.Fd(), unix.F_OFD_SETLK, &lock)
+		if errno, _ := err.(unix.Errno); errno != unix.EAGAIN {
+			return err
+		}
+		if timeout < time.Millisecond {
+			return err
+		}
+		timeout -= time.Millisecond
+		time.Sleep(time.Millisecond)
+	}
+}

vfs_os_posix.go

@@ -0,0 +1,30 @@
+//go:build !windows && !linux && !darwin
+
+package sqlite3
+
+import (
+	"os"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+func (vfsOSMethods) Sync(file *os.File, fullsync, dataonly bool) error {
+	return file.Sync()
+}
+
+func (vfsOSMethods) Allocate(file *os.File, size int64) error {
+	return notImplErr
+}
+
+func (vfsOSMethods) fcntlGetLock(file *os.File, lock *unix.Flock_t) error {
+	return notImplErr
+}
+
+func (vfsOSMethods) fcntlSetLock(file *os.File, lock unix.Flock_t) error {
+	return notImplErr
+}
+
+func (vfsOSMethods) fcntlSetLockTimeout(file *os.File, lock unix.Flock_t, timeout time.Duration) error {
+	return notImplErr
+}

vfs_os_unix.go

@@ -0,0 +1,119 @@
+//go:build unix
+
+package sqlite3
+
+import (
+	"io/fs"
+	"os"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+func (vfsOSMethods) OpenFile(name string, flag int, perm fs.FileMode) (*os.File, error) {
+	return os.OpenFile(name, flag, perm)
+}
+
+func (vfsOSMethods) Access(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 (vfsOSMethods) GetExclusiveLock(file *os.File, timeout time.Duration) xErrorCode {
+	if timeout == 0 {
+		timeout = time.Millisecond
+	}
+
+	// Acquire the EXCLUSIVE lock.
+	return vfsOS.writeLock(file, _SHARED_FIRST, _SHARED_SIZE, timeout)
+}
+
+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, 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 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, unix.Flock_t{
+		Type:  unix.F_UNLCK,
+		Start: start,
+		Len:   len,
+	})
+	if err != nil {
+		return IOERR_UNLOCK
+	}
+	return _OK
+}
+
+func (vfsOSMethods) readLock(file *os.File, start, len int64, timeout time.Duration) xErrorCode {
+	return vfsOS.lockErrorCode(vfsOS.fcntlSetLockTimeout(file, unix.Flock_t{
+		Type:  unix.F_RDLCK,
+		Start: start,
+		Len:   len,
+	}, timeout), IOERR_RDLOCK)
+}
+
+func (vfsOSMethods) writeLock(file *os.File, start, len int64, timeout time.Duration) xErrorCode {
+	// TODO: implement timeouts.
+	return vfsOS.lockErrorCode(vfsOS.fcntlSetLockTimeout(file, unix.Flock_t{
+		Type:  unix.F_WRLCK,
+		Start: start,
+		Len:   len,
+	}, timeout), IOERR_LOCK)
+}
+
+func (vfsOSMethods) checkLock(file *os.File, start, len int64) (bool, xErrorCode) {
+	lock := unix.Flock_t{
+		Type:  unix.F_RDLCK,
+		Start: start,
+		Len:   len,
+	}
+	if vfsOS.fcntlGetLock(file, &lock) != nil {
+		return false, IOERR_CHECKRESERVEDLOCK
+	}
+	return lock.Type != unix.F_UNLCK, _OK
+}
+
+func (vfsOSMethods) lockErrorCode(err error, def xErrorCode) xErrorCode {
+	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 xErrorCode(BUSY)
+		case unix.EPERM:
+			return xErrorCode(PERM)
+		}
+	}
+	return def
+}

vfs_os_windows.go

@@ -0,0 +1,240 @@
+package sqlite3
+
+import (
+	"io"
+	"io/fs"
+	"os"
+	"syscall"
+	"time"
+
+	"golang.org/x/sys/windows"
+)
+
+// OpenFile 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 (vfsOSMethods) OpenFile(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 (vfsOSMethods) Access(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 (vfsOSMethods) Sync(file *os.File, fullsync, dataonly bool) error {
+	return file.Sync()
+}
+
+func (vfsOSMethods) Allocate(file *os.File, size int64) error {
+	off, err := file.Seek(0, io.SeekEnd)
+	if err != nil {
+		return err
+	}
+	if size > off {
+		return file.Truncate(size)
+	}
+	return nil
+}
+
+func (vfsOSMethods) GetExclusiveLock(file *os.File, timeout time.Duration) xErrorCode {
+	if timeout == 0 {
+		timeout = time.Millisecond
+	}
+
+	// Release the SHARED lock.
+	vfsOS.unlock(file, _SHARED_FIRST, _SHARED_SIZE)
+
+	// Acquire the EXCLUSIVE lock.
+	rc := vfsOS.writeLock(file, _SHARED_FIRST, _SHARED_SIZE, timeout)
+
+	// Reacquire the SHARED lock.
+	if rc != _OK {
+		vfsOS.readLock(file, _SHARED_FIRST, _SHARED_SIZE, 0)
+	}
+	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, 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 >= _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 == windows.ERROR_NOT_LOCKED {
+		return _OK
+	}
+	if err != nil {
+		return IOERR_UNLOCK
+	}
+	return _OK
+}
+
+func (vfsOSMethods) lock(file *os.File, flags, start, len uint32, timeout time.Duration, def xErrorCode) xErrorCode {
+	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 {
+			return vfsOS.lockErrorCode(err, def)
+		}
+		if timeout < time.Millisecond {
+			return vfsOS.lockErrorCode(err, def)
+		}
+		timeout -= time.Millisecond
+		time.Sleep(time.Millisecond)
+	}
+}
+
+func (vfsOSMethods) readLock(file *os.File, start, len uint32, timeout time.Duration) xErrorCode {
+	return vfsOS.lock(file,
+		windows.LOCKFILE_FAIL_IMMEDIATELY,
+		start, len, timeout, IOERR_RDLOCK)
+}
+
+func (vfsOSMethods) writeLock(file *os.File, start, len uint32, timeout time.Duration) xErrorCode {
+	return vfsOS.lock(file,
+		windows.LOCKFILE_FAIL_IMMEDIATELY|windows.LOCKFILE_EXCLUSIVE_LOCK,
+		start, len, timeout, IOERR_LOCK)
+}
+
+func (vfsOSMethods) checkLock(file *os.File, start, len uint32) (bool, xErrorCode) {
+	rc := vfsOS.lock(file,
+		windows.LOCKFILE_FAIL_IMMEDIATELY,
+		start, len, 0, IOERR_CHECKRESERVEDLOCK)
+	if rc == xErrorCode(BUSY) {
+		return true, _OK
+	}
+	if rc == _OK {
+		vfsOS.unlock(file, start, len)
+	}
+	return false, rc
+}
+
+func (vfsOSMethods) lockErrorCode(err error, def xErrorCode) xErrorCode {
+	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 xErrorCode(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)
+}

vfs_test.go

@@ -16,15 +16,17 @@ import (
 
 func Test_vfsExit(t *testing.T) {
 	mem := newMemory(128)
+	ctx := context.TODO()
 	defer func() { _ = recover() }()
-	vfsExit(context.TODO(), mem.mod, 1)
+	vfsExit(ctx, mem.mod, 1)
 	t.Error("want panic")
 }
 
 func Test_vfsLocaltime(t *testing.T) {
 	mem := newMemory(128)
+	ctx := context.TODO()
 
-	rc := vfsLocaltime(context.TODO(), mem.mod, 0, 4)
+	rc := vfsLocaltime(ctx, mem.mod, 0, 4)
 	if rc != 0 {
 		t.Fatal("returned", rc)
 	}
@@ -71,24 +73,26 @@ func Test_vfsRandomness(t *testing.T) {
 }
 
 func Test_vfsSleep(t *testing.T) {
-	start := time.Now()
+	ctx := context.TODO()
 
-	rc := vfsSleep(context.TODO(), 0, 123456)
+	now := time.Now()
+	rc := vfsSleep(ctx, 0, 123456)
 	if rc != 0 {
 		t.Fatal("returned", rc)
 	}
 
 	want := 123456 * time.Microsecond
-	if got := time.Since(start); got < want {
+	if got := time.Since(now); got < want {
 		t.Errorf("got %v, want %v", got, want)
 	}
 }
 
 func Test_vfsCurrentTime(t *testing.T) {
 	mem := newMemory(128)
+	ctx := context.TODO()
 
 	now := time.Now()
-	rc := vfsCurrentTime(context.TODO(), mem.mod, 0, 4)
+	rc := vfsCurrentTime(ctx, mem.mod, 0, 4)
 	if rc != 0 {
 		t.Fatal("returned", rc)
 	}
@@ -101,10 +105,11 @@ func Test_vfsCurrentTime(t *testing.T) {
 
 func Test_vfsCurrentTime64(t *testing.T) {
 	mem := newMemory(128)
+	ctx := context.TODO()
 
 	now := time.Now()
 	time.Sleep(time.Millisecond)
-	rc := vfsCurrentTime64(context.TODO(), mem.mod, 0, 4)
+	rc := vfsCurrentTime64(ctx, mem.mod, 0, 4)
 	if rc != 0 {
 		t.Fatal("returned", rc)
 	}
@@ -119,13 +124,14 @@ func Test_vfsCurrentTime64(t *testing.T) {
 func Test_vfsFullPathname(t *testing.T) {
 	mem := newMemory(128 + _MAX_PATHNAME)
 	mem.writeString(4, ".")
+	ctx := context.TODO()
 
-	rc := vfsFullPathname(context.TODO(), mem.mod, 0, 4, 0, 8)
+	rc := vfsFullPathname(ctx, 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)
+	rc = vfsFullPathname(ctx, mem.mod, 0, 4, _MAX_PATHNAME, 8)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
@@ -147,8 +153,9 @@ func Test_vfsDelete(t *testing.T) {
 
 	mem := newMemory(128 + _MAX_PATHNAME)
 	mem.writeString(4, name)
+	ctx := context.TODO()
 
-	rc := vfsDelete(context.TODO(), mem.mod, 0, 4, 1)
+	rc := vfsDelete(ctx, mem.mod, 0, 4, 1)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
@@ -157,8 +164,8 @@ func Test_vfsDelete(t *testing.T) {
 		t.Fatal("did not delete the file")
 	}
 
-	rc = vfsDelete(context.TODO(), mem.mod, 0, 4, 1)
-	if rc != _OK {
+	rc = vfsDelete(ctx, mem.mod, 0, 4, 1)
+	if rc != uint32(IOERR_DELETE_NOENT) {
 		t.Fatal("returned", rc)
 	}
 }
@@ -177,8 +184,9 @@ func Test_vfsAccess(t *testing.T) {
 
 	mem := newMemory(128 + _MAX_PATHNAME)
 	mem.writeString(8, dir)
+	ctx := context.TODO()
 
-	rc := vfsAccess(context.TODO(), mem.mod, 0, 8, _ACCESS_EXISTS, 4)
+	rc := vfsAccess(ctx, mem.mod, 0, 8, _ACCESS_EXISTS, 4)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
@@ -186,7 +194,7 @@ func Test_vfsAccess(t *testing.T) {
 		t.Error("directory did not exist")
 	}
 
-	rc = vfsAccess(context.TODO(), mem.mod, 0, 8, _ACCESS_READWRITE, 4)
+	rc = vfsAccess(ctx, mem.mod, 0, 8, _ACCESS_READWRITE, 4)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
@@ -195,7 +203,7 @@ func Test_vfsAccess(t *testing.T) {
 	}
 
 	mem.writeString(8, file)
-	rc = vfsAccess(context.TODO(), mem.mod, 0, 8, _ACCESS_READWRITE, 4)
+	rc = vfsAccess(ctx, mem.mod, 0, 8, _ACCESS_READWRITE, 4)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
@@ -206,9 +214,11 @@ func Test_vfsAccess(t *testing.T) {
 
 func Test_vfsFile(t *testing.T) {
 	mem := newMemory(128)
+	ctx, vfs := vfsContext(context.TODO())
+	defer vfs.Close()
 
 	// Open a temporary file.
-	rc := vfsOpen(context.TODO(), mem.mod, 0, 0, 4, OPEN_CREATE|OPEN_EXCLUSIVE|OPEN_READWRITE|OPEN_DELETEONCLOSE, 0)
+	rc := vfsOpen(ctx, mem.mod, 0, 0, 4, OPEN_CREATE|OPEN_EXCLUSIVE|OPEN_READWRITE|OPEN_DELETEONCLOSE, 0)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
@@ -216,13 +226,13 @@ func Test_vfsFile(t *testing.T) {
 	// Write stuff.
 	text := "Hello world!"
 	mem.writeString(16, text)
-	rc = vfsWrite(context.TODO(), mem.mod, 4, 16, uint32(len(text)), 0)
+	rc = vfsWrite(ctx, 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)
+	rc = vfsFileSize(ctx, mem.mod, 4, 16)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
@@ -231,7 +241,7 @@ func Test_vfsFile(t *testing.T) {
 	}
 
 	// Partial read at offset.
-	rc = vfsRead(context.TODO(), mem.mod, 4, 16, uint32(len(text)), 4)
+	rc = vfsRead(ctx, mem.mod, 4, 16, uint32(len(text)), 4)
 	if rc != uint32(IOERR_SHORT_READ) {
 		t.Fatal("returned", rc)
 	}
@@ -240,13 +250,13 @@ func Test_vfsFile(t *testing.T) {
 	}
 
 	// Truncate the file.
-	rc = vfsTruncate(context.TODO(), mem.mod, 4, 4)
+	rc = vfsTruncate(ctx, mem.mod, 4, 4)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
 
 	// Check file size.
-	rc = vfsFileSize(context.TODO(), mem.mod, 4, 16)
+	rc = vfsFileSize(ctx, mem.mod, 4, 16)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
@@ -255,7 +265,7 @@ func Test_vfsFile(t *testing.T) {
 	}
 
 	// Read at offset.
-	rc = vfsRead(context.TODO(), mem.mod, 4, 32, 4, 0)
+	rc = vfsRead(ctx, mem.mod, 4, 32, 4, 0)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
@@ -264,7 +274,7 @@ func Test_vfsFile(t *testing.T) {
 	}
 
 	// Close the file.
-	rc = vfsClose(context.TODO(), mem.mod, 4)
+	rc = vfsClose(ctx, mem.mod, 4)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}

vfs_unix.go

@@ -1,158 +0,0 @@
-//go:build unix
-
-package sqlite3
-
-import (
-	"os"
-	"runtime"
-	"syscall"
-)
-
-func deleteOnClose(f *os.File) {
-	_ = os.Remove(f.Name())
-}
-
-func (l *vfsFileLocker) GetShared() xErrorCode {
-	// Acquire the SHARED lock.
-	return l.readLock(_SHARED_FIRST, _SHARED_SIZE)
-}
-
-func (l *vfsFileLocker) GetReserved() xErrorCode {
-	// Acquire the RESERVED lock.
-	return l.writeLock(_RESERVED_BYTE, 1)
-}
-
-func (l *vfsFileLocker) GetPending() xErrorCode {
-	// Acquire the PENDING lock.
-	return l.writeLock(_PENDING_BYTE, 1)
-}
-
-func (l *vfsFileLocker) GetExclusive() xErrorCode {
-	// Acquire the EXCLUSIVE lock.
-	return l.writeLock(_SHARED_FIRST, _SHARED_SIZE)
-}
-
-func (l *vfsFileLocker) Downgrade() xErrorCode {
-	if l.state >= _EXCLUSIVE_LOCK {
-		// Downgrade to a SHARED lock.
-		if rc := l.readLock(_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 l.unlock(_PENDING_BYTE, 2)
-}
-
-func (l *vfsFileLocker) Release() xErrorCode {
-	// Release all locks.
-	return l.unlock(0, 0)
-}
-
-func (l *vfsFileLocker) CheckReserved() (bool, xErrorCode) {
-	// Test the RESERVED lock.
-	return l.checkLock(_RESERVED_BYTE, 1)
-}
-
-func (l *vfsFileLocker) CheckPending() (bool, xErrorCode) {
-	// Test the PENDING lock.
-	return l.checkLock(_PENDING_BYTE, 1)
-}
-
-func (l *vfsFileLocker) unlock(start, len int64) xErrorCode {
-	err := l.fcntlSetLock(&syscall.Flock_t{
-		Type:  syscall.F_UNLCK,
-		Start: start,
-		Len:   len,
-	})
-	if err != nil {
-		return IOERR_UNLOCK
-	}
-	return _OK
-}
-
-func (l *vfsFileLocker) readLock(start, len int64) xErrorCode {
-	return l.errorCode(l.fcntlSetLock(&syscall.Flock_t{
-		Type:  syscall.F_RDLCK,
-		Start: start,
-		Len:   len,
-	}), IOERR_RDLOCK)
-}
-
-func (l *vfsFileLocker) writeLock(start, len int64) xErrorCode {
-	return l.errorCode(l.fcntlSetLock(&syscall.Flock_t{
-		Type:  syscall.F_WRLCK,
-		Start: start,
-		Len:   len,
-	}), IOERR_LOCK)
-}
-
-func (l *vfsFileLocker) checkLock(start, len int64) (bool, xErrorCode) {
-	lock := syscall.Flock_t{
-		Type:  syscall.F_RDLCK,
-		Start: start,
-		Len:   len,
-	}
-	if l.fcntlGetLock(&lock) != nil {
-		return false, IOERR_CHECKRESERVEDLOCK
-	}
-	return lock.Type != syscall.F_UNLCK, _OK
-}
-
-func (l *vfsFileLocker) fcntlGetLock(lock *syscall.Flock_t) error {
-	F_GETLK := syscall.F_GETLK
-	switch runtime.GOOS {
-	case "linux":
-		// https://github.com/torvalds/linux/blob/master/include/uapi/asm-generic/fcntl.h
-		F_GETLK = 36 // F_OFD_GETLK
-	case "darwin":
-		// https://github.com/apple/darwin-xnu/blob/main/bsd/sys/fcntl.h
-		F_GETLK = 92 // F_OFD_GETLK
-	case "illumos":
-		// https://github.com/illumos/illumos-gate/blob/master/usr/src/uts/common/sys/fcntl.h
-		F_GETLK = 47 // F_OFD_GETLK
-	}
-	return syscall.FcntlFlock(l.file.Fd(), F_GETLK, lock)
-}
-
-func (l *vfsFileLocker) fcntlSetLock(lock *syscall.Flock_t) error {
-	F_SETLK := syscall.F_SETLK
-	switch runtime.GOOS {
-	case "linux":
-		// https://github.com/torvalds/linux/blob/master/include/uapi/asm-generic/fcntl.h
-		F_SETLK = 37 // F_OFD_SETLK
-	case "darwin":
-		// https://github.com/apple/darwin-xnu/blob/main/bsd/sys/fcntl.h
-		F_SETLK = 90 // F_OFD_SETLK
-	case "illumos":
-		// https://github.com/illumos/illumos-gate/blob/master/usr/src/uts/common/sys/fcntl.h
-		F_SETLK = 48 // F_OFD_SETLK
-	}
-	return syscall.FcntlFlock(l.file.Fd(), F_SETLK, lock)
-}
-
-func (*vfsFileLocker) errorCode(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

@@ -1,127 +0,0 @@
-package sqlite3
-
-import (
-	"os"
-	"syscall"
-
-	"golang.org/x/sys/windows"
-)
-
-func deleteOnClose(f *os.File) {}
-
-func (l *vfsFileLocker) GetShared() xErrorCode {
-	// Acquire the SHARED lock.
-	return l.readLock(_SHARED_FIRST, _SHARED_SIZE)
-}
-
-func (l *vfsFileLocker) GetReserved() xErrorCode {
-	// Acquire the RESERVED lock.
-	return l.writeLock(_RESERVED_BYTE, 1)
-}
-
-func (l *vfsFileLocker) GetPending() xErrorCode {
-	// Acquire the PENDING lock.
-	return l.writeLock(_PENDING_BYTE, 1)
-}
-
-func (l *vfsFileLocker) GetExclusive() xErrorCode {
-	// Release the SHARED lock.
-	l.unlock(_SHARED_FIRST, _SHARED_SIZE)
-
-	// Acquire the EXCLUSIVE lock.
-	rc := l.writeLock(_SHARED_FIRST, _SHARED_SIZE)
-
-	// Reacquire the SHARED lock.
-	if rc != _OK {
-		l.readLock(_SHARED_FIRST, _SHARED_SIZE)
-	}
-	return rc
-}
-
-func (l *vfsFileLocker) Downgrade() xErrorCode {
-	if l.state >= _EXCLUSIVE_LOCK {
-		// Release the SHARED lock.
-		l.unlock(_SHARED_FIRST, _SHARED_SIZE)
-
-		// Reacquire the SHARED lock.
-		if rc := l.readLock(_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 l.state >= _RESERVED_LOCK {
-		l.unlock(_RESERVED_BYTE, 1)
-	}
-	if l.state >= _PENDING_LOCK {
-		l.unlock(_PENDING_BYTE, 1)
-	}
-	return _OK
-}
-
-func (l *vfsFileLocker) Release() xErrorCode {
-	// Release all locks.
-	if l.state >= _RESERVED_LOCK {
-		l.unlock(_RESERVED_BYTE, 1)
-	}
-	if l.state >= _SHARED_LOCK {
-		l.unlock(_SHARED_FIRST, _SHARED_SIZE)
-	}
-	if l.state >= _PENDING_LOCK {
-		l.unlock(_PENDING_BYTE, 1)
-	}
-	return _OK
-}
-
-func (l *vfsFileLocker) CheckReserved() (bool, xErrorCode) {
-	// Test the RESERVED lock.
-	rc := l.readLock(_RESERVED_BYTE, 1)
-	if rc == _OK {
-		l.unlock(_RESERVED_BYTE, 1)
-	}
-	return rc != _OK, _OK
-}
-
-func (l *vfsFileLocker) CheckPending() (bool, xErrorCode) {
-	// Test the PENDING lock.
-	rc := l.readLock(_PENDING_BYTE, 1)
-	if rc == _OK {
-		l.unlock(_PENDING_BYTE, 1)
-	}
-	return rc != _OK, _OK
-}
-
-func (l *vfsFileLocker) unlock(start, len uint32) xErrorCode {
-	err := windows.UnlockFileEx(windows.Handle(l.file.Fd()),
-		0, len, 0, &windows.Overlapped{Offset: start})
-	if err != nil {
-		return IOERR_UNLOCK
-	}
-	return _OK
-}
-
-func (l *vfsFileLocker) readLock(start, len uint32) xErrorCode {
-	return l.errorCode(windows.LockFileEx(windows.Handle(l.file.Fd()),
-		windows.LOCKFILE_FAIL_IMMEDIATELY,
-		0, len, 0, &windows.Overlapped{Offset: start}),
-		IOERR_RDLOCK)
-}
-
-func (l *vfsFileLocker) writeLock(start, len uint32) xErrorCode {
-	return l.errorCode(windows.LockFileEx(windows.Handle(l.file.Fd()),
-		windows.LOCKFILE_FAIL_IMMEDIATELY|windows.LOCKFILE_EXCLUSIVE_LOCK,
-		0, len, 0, &windows.Overlapped{Offset: start}),
-		IOERR_LOCK)
-}
-
-func (*vfsFileLocker) errorCode(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)
-}