wazero 1.0.2.

.github/workflows/go.yml

@@ -46,16 +46,12 @@ jobs:
     - name: Test
       run: go test -v ./...
 
-    - name: Test data races
-      run: go test -v -race ./...
-      if: matrix.os == 'ubuntu-latest'
-
     - name: Test BSD locks
       run: go test -v -tags sqlite3_bsd ./...
       if: matrix.os == 'macos-latest'
 
     - name: Coverage report
-      uses: ncruces/go-coverage-report@main
+      uses: ncruces/go-coverage-report@v0
       with:
         chart: 'true'
         amend: 'true'

README.md

@@ -19,7 +19,7 @@ embeds a build of SQLite into your application.
 ### Caveats
 
 This module replaces the SQLite [OS Interface](https://www.sqlite.org/vfs.html) (aka VFS)
-with a pure Go implementation.
+with a [pure Go](internal/vfs/) implementation.
 This has numerous benefits, but also comes with some drawbacks.
 
 #### Write-Ahead Logging

blob.go

@@ -1,6 +1,10 @@
 package sqlite3
 
-import "io"
+import (
+	"io"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
+)
 
 // ZeroBlob represents a zero-filled, length n BLOB
 // that can be used as an argument to
@@ -14,9 +18,9 @@ type ZeroBlob int64
 // https://www.sqlite.org/c3ref/blob.html
 type Blob struct {
 	c      *Conn
-	handle uint32
 	bytes  int64
 	offset int64
+	handle uint32
 }
 
 var _ io.ReadWriteSeeker = &Blob{}
@@ -46,7 +50,7 @@ func (c *Conn) OpenBlob(db, table, column string, row int64, write bool) (*Blob,
 	}
 
 	blob := Blob{c: c}
-	blob.handle = c.mem.readUint32(blobPtr)
+	blob.handle = util.ReadUint32(c.mod, blobPtr)
 	blob.bytes = int64(c.call(c.api.blobBytes, uint64(blob.handle))[0])
 	return &blob, nil
 }
@@ -98,7 +102,7 @@ func (b *Blob) Read(p []byte) (n int, err error) {
 		return 0, err
 	}
 
-	mem := b.c.mem.view(ptr, uint64(want))
+	mem := util.View(b.c.mod, ptr, uint64(want))
 	copy(p, mem)
 	b.offset += want
 	if b.offset >= b.bytes {
@@ -133,7 +137,7 @@ func (b *Blob) Write(p []byte) (n int, err error) {
 func (b *Blob) Seek(offset int64, whence int) (int64, error) {
 	switch whence {
 	default:
-		return 0, whenceErr
+		return 0, util.WhenceErr
 	case io.SeekStart:
 		break
 	case io.SeekCurrent:
@@ -142,7 +146,7 @@ func (b *Blob) Seek(offset int64, whence int) (int64, error) {
 		offset += b.bytes
 	}
 	if offset < 0 {
-		return 0, offsetErr
+		return 0, util.OffsetErr
 	}
 	b.offset = offset
 	return offset, nil

conn.go

@@ -10,6 +10,8 @@ import (
 	"strings"
 	"sync/atomic"
 	"unsafe"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
 )
 
 // Conn is a database connection handle.
@@ -19,11 +21,12 @@ import (
 type Conn struct {
 	*module
 
-	handle    uint32
-	arena     arena
 	interrupt context.Context
 	waiter    chan struct{}
 	pending   *Stmt
+	arena     arena
+
+	handle uint32
 }
 
 // Open calls [OpenFlags] with [OPEN_READWRITE], [OPEN_CREATE], [OPEN_URI] and [OPEN_NOFOLLOW].
@@ -55,7 +58,7 @@ func newConn(filename string, flags OpenFlag) (conn *Conn, err error) {
 		if conn == nil {
 			mod.close()
 		} else {
-			runtime.SetFinalizer(conn, finalizer[Conn](3))
+			runtime.SetFinalizer(conn, util.Finalizer[Conn](3))
 		}
 	}()
 
@@ -76,7 +79,7 @@ func (c *Conn) openDB(filename string, flags OpenFlag) (uint32, error) {
 	flags |= OPEN_EXRESCODE
 	r := c.call(c.api.open, uint64(namePtr), uint64(connPtr), uint64(flags), 0)
 
-	handle := c.mem.readUint32(connPtr)
+	handle := util.ReadUint32(c.mod, connPtr)
 	if err := c.module.error(r[0], handle); err != nil {
 		c.closeDB(handle)
 		return 0, err
@@ -182,8 +185,8 @@ func (c *Conn) PrepareFlags(sql string, flags PrepareFlag) (stmt *Stmt, tail str
 		uint64(stmtPtr), uint64(tailPtr))
 
 	stmt = &Stmt{c: c}
-	stmt.handle = c.mem.readUint32(stmtPtr)
-	i := c.mem.readUint32(tailPtr)
+	stmt.handle = util.ReadUint32(c.mod, stmtPtr)
+	i := util.ReadUint32(c.mod, tailPtr)
 	tail = sql[i-sqlPtr:]
 
 	if err := c.error(r[0], sql); err != nil {
@@ -275,7 +278,7 @@ func (c *Conn) SetInterrupt(ctx context.Context) (old context.Context) {
 			break
 
 		case <-ctx.Done(): // Done was closed.
-			buf := c.mem.view(c.handle+c.api.interrupt, 4)
+			buf := util.View(c.mod, c.handle+c.api.interrupt, 4)
 			(*atomic.Uint32)(unsafe.Pointer(&buf[0])).Store(1)
 			// Wait for the next call to SetInterrupt.
 			<-waiter
@@ -291,7 +294,7 @@ 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)
+	buf := util.View(c.mod, c.handle+c.api.interrupt, 4)
 	(*atomic.Uint32)(unsafe.Pointer(&buf[0])).Store(1)
 	return true
 }

const.go

@@ -7,12 +7,9 @@ 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_STRING = 512 // Used for short strings: names, error messages…
 
 	_MAX_ALLOCATION_SIZE = 0x7ffffeff
 
@@ -211,65 +208,3 @@ 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

@@ -35,6 +35,7 @@ import (
 	"time"
 
 	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
 )
 
 func init() {
@@ -44,12 +45,12 @@ func init() {
 type sqlite struct{}
 
 func (sqlite) Open(name string) (_ driver.Conn, err error) {
-	c, err := sqlite3.Open(name)
+	var c conn
+	c.conn, err = sqlite3.Open(name)
 	if err != nil {
 		return nil, err
 	}
 
-	var txBegin string
 	var pragmas []string
 	if strings.HasPrefix(name, "file:") {
 		if _, after, ok := strings.Cut(name, "?"); ok {
@@ -57,9 +58,9 @@ func (sqlite) Open(name string) (_ driver.Conn, err error) {
 
 			switch s := query.Get("_txlock"); s {
 			case "":
-				txBegin = "BEGIN"
+				c.txBegin = "BEGIN"
 			case "deferred", "immediate", "exclusive":
-				txBegin = "BEGIN " + s
+				c.txBegin = "BEGIN " + s
 			default:
 				c.Close()
 				return nil, fmt.Errorf("sqlite3: invalid _txlock: %s", s)
@@ -69,20 +70,36 @@ func (sqlite) Open(name string) (_ driver.Conn, err error) {
 		}
 	}
 	if len(pragmas) == 0 {
-		err := c.Exec(`
-			PRAGMA busy_timeout=60000;
+		err := c.conn.Exec(`
 			PRAGMA locking_mode=normal;
+			PRAGMA busy_timeout=60000;
 		`)
 		if err != nil {
 			c.Close()
 			return nil, err
 		}
+		c.reusable = true
+	} else {
+		s, _, err := c.conn.Prepare(`
+			SELECT * FROM
+				PRAGMA_locking_mode,
+				PRAGMA_query_only;
+		`)
+		if err != nil {
+			c.Close()
+			return nil, err
+		}
+		if s.Step() {
+			c.reusable = s.ColumnText(0) == "normal"
+			c.readOnly = s.ColumnRawText(1)[0] // 0 or 1
+		}
+		err = s.Close()
+		if err != nil {
+			c.Close()
+			return nil, err
+		}
 	}
-
-	return conn{
-		conn:    c,
-		txBegin: txBegin,
-	}, nil
+	return c, nil
 }
 
 type conn struct {
@@ -90,6 +107,8 @@ type conn struct {
 	txBegin    string
 	txCommit   string
 	txRollback string
+	reusable   bool
+	readOnly   byte
 }
 
 var (
@@ -104,9 +123,8 @@ func (c conn) Close() error {
 	return c.conn.Close()
 }
 
-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) IsValid() bool {
+	return c.reusable
 }
 
 func (c conn) Begin() (driver.Tx, error) {
@@ -119,34 +137,22 @@ func (c conn) BeginTx(_ context.Context, opts driver.TxOptions) (driver.Tx, erro
 	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]
+			PRAGMA query_only=` + string(c.readOnly)
 		c.txRollback = c.txCommit
 	}
 
 	switch opts.Isolation {
 	default:
-		return nil, isolationErr
+		return nil, util.IsolationErr
 	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]
 	}
 
 	err := c.conn.Exec(txBegin)
@@ -183,7 +189,7 @@ func (c conn) Prepare(query string) (driver.Stmt, error) {
 		if st != nil {
 			s.Close()
 			st.Close()
-			return nil, tailErr
+			return nil, util.TailErr
 		}
 	}
 	return stmt{s, c.conn}, nil
@@ -312,11 +318,11 @@ func (s stmt) QueryContext(ctx context.Context, args []driver.NamedValue) (drive
 			case sqlite3.ZeroBlob:
 				err = s.stmt.BindZeroBlob(id, int64(a))
 			case time.Time:
-				err = s.stmt.BindText(id, a.Format(time.RFC3339Nano))
+				err = s.stmt.BindTime(id, a, sqlite3.TimeFormatDefault)
 			case nil:
 				err = s.stmt.BindNull(id)
 			default:
-				panic(assertErr)
+				panic(util.AssertErr())
 			}
 		}
 		if err != nil {
@@ -383,10 +389,10 @@ func (r rows) Next(dest []driver.Value) error {
 			dest[i] = r.stmt.ColumnInt64(i)
 		case sqlite3.FLOAT:
 			dest[i] = r.stmt.ColumnFloat(i)
-		case sqlite3.TEXT:
-			dest[i] = maybeTime(r.stmt.ColumnText(i))
 		case sqlite3.BLOB:
 			dest[i] = r.stmt.ColumnRawBlob(i)
+		case sqlite3.TEXT:
+			dest[i] = stringOrTime(r.stmt.ColumnRawText(i))
 		case sqlite3.NULL:
 			if buf, ok := dest[i].([]byte); ok {
 				dest[i] = buf[0:0]
@@ -394,7 +400,7 @@ func (r rows) Next(dest []driver.Value) error {
 				dest[i] = nil
 			}
 		default:
-			panic(assertErr)
+			panic(util.AssertErr())
 		}
 	}
 

driver/driver_test.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
 )
 
 func Test_Open_dir(t *testing.T) {
@@ -142,20 +143,10 @@ func Test_BeginTx(t *testing.T) {
 	defer db.Close()
 
 	_, err = db.BeginTx(ctx, &sql.TxOptions{Isolation: sql.LevelReadCommitted})
-	if err.Error() != string(isolationErr) {
+	if err.Error() != string(util.IsolationErr) {
 		t.Error("want isolationErr")
 	}
 
-	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)
@@ -230,7 +221,7 @@ func Test_Prepare(t *testing.T) {
 	}
 
 	_, err = db.Prepare(`SELECT 1; SELECT 2`)
-	if err.Error() != string(tailErr) {
+	if err.Error() != string(util.TailErr) {
 		t.Error("want tailErr")
 	}
 }

driver/error.go

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

driver/time.go

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

driver/time_test.go

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

embed/README.md

@@ -19,4 +19,5 @@ The following optional features are compiled in:
 
 See the [configuration options](../sqlite3/sqlite_cfg.h).
 
-Built using [`zig`](https://ziglang.org/) version 0.10.1.
+Built using [`wasi-sdk`](https://github.com/WebAssembly/wasi-sdk),
+and [`binaryen`](https://github.com/WebAssembly/binaryen).

embed/build.sh

@@ -1,15 +1,28 @@
 #!/usr/bin/env bash
-set -eo pipefail
+set -euo pipefail
 
 cd -P -- "$(dirname -- "$0")"
 
-# build SQLite
-zig cc --target=wasm32-wasi -flto -g0 -O2 \
-  -o sqlite3.wasm ../sqlite3/main.c \
-	-I../sqlite3/ \
+ROOT=../
+BINARYEN="$ROOT/tools/binaryen-version_112/bin"
+WASI_SDK="$ROOT/tools/wasi-sdk-20.0/bin"
+
+"$WASI_SDK/clang" --target=wasm32-wasi -flto -g0 -O2 \
+	-o sqlite3.wasm "$ROOT/sqlite3/main.c" \
+	-I"$ROOT/sqlite3" \
+	-mexec-model=reactor \
 	-mmutable-globals \
 	-mbulk-memory -mreference-types \
 	-mnontrapping-fptoint -msign-ext \
-	-mexec-model=reactor \
+	-Wl,--initial-memory=327680 \
+	-Wl,--stack-first \
+	-Wl,--import-undefined \
 	-D_HAVE_SQLITE_CONFIG_H \
-	$(awk '{print "-Wl,--export="$0}' exports.txt)
+	$(awk '{print "-Wl,--export="$0}' exports.txt)
+
+trap 'rm -f sqlite3.tmp' EXIT
+"$BINARYEN/wasm-ctor-eval" -g -c _initialize sqlite3.wasm -o sqlite3.tmp
+"$BINARYEN/wasm-opt" -g -O2 sqlite3.tmp -o sqlite3.wasm \
+	--enable-multivalue --enable-mutable-globals \
+	--enable-bulk-memory --enable-reference-types \
+	--enable-nontrapping-float-to-int --enable-sign-ext

error.go

@@ -1,8 +1,6 @@
 package sqlite3
 
 import (
-	"fmt"
-	"runtime"
 	"strconv"
 	"strings"
 )
@@ -11,10 +9,10 @@ import (
 //
 // https://www.sqlite.org/c3ref/errcode.html
 type Error struct {
-	code uint64
 	str  string
 	msg  string
 	sql  string
+	code uint64
 }
 
 // Code returns the primary error code for this error.
@@ -188,36 +186,3 @@ func (e ExtendedErrorCode) Temporary() bool {
 func (e ExtendedErrorCode) Timeout() bool {
 	return e == BUSY_TIMEOUT
 }
-
-type errorString string
-
-func (e errorString) Error() string { return string(e) }
-
-const (
-	nilErr      = errorString("sqlite3: invalid memory address or null pointer dereference")
-	oomErr      = errorString("sqlite3: out of memory")
-	rangeErr    = errorString("sqlite3: index out of range")
-	noNulErr    = errorString("sqlite3: missing NUL terminator")
-	noGlobalErr = errorString("sqlite3: could not find global: ")
-	noFuncErr   = errorString("sqlite3: could not find function: ")
-	binaryErr   = errorString("sqlite3: no SQLite binary embed/set/loaded")
-	timeErr     = errorString("sqlite3: invalid time value")
-	whenceErr   = errorString("sqlite3: invalid whence")
-	offsetErr   = errorString("sqlite3: invalid offset")
-)
-
-func assertErr() errorString {
-	msg := "sqlite3: assertion failed"
-	if _, file, line, ok := runtime.Caller(1); ok {
-		msg += " (" + file + ":" + strconv.Itoa(line) + ")"
-	}
-	return errorString(msg)
-}
-
-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

@@ -4,11 +4,13 @@ import (
 	"errors"
 	"strings"
 	"testing"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
 )
 
 func Test_assertErr(t *testing.T) {
-	err := assertErr()
-	if s := err.Error(); !strings.HasPrefix(s, "sqlite3: assertion failed") || !strings.HasSuffix(s, "error_test.go:10)") {
+	err := util.AssertErr()
+	if s := err.Error(); !strings.HasPrefix(s, "sqlite3: assertion failed") || !strings.HasSuffix(s, "error_test.go:12)") {
 		t.Errorf("got %q", s)
 	}
 }
@@ -120,7 +122,7 @@ func Test_ErrorCode_Error(t *testing.T) {
 	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)
+		want += util.ReadString(db.mod, uint32(r[0]), _MAX_STRING)
 
 		got := ErrorCode(i).Error()
 		if got != want {
@@ -142,7 +144,7 @@ func Test_ExtendedErrorCode_Error(t *testing.T) {
 	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)
+		want += util.ReadString(db.mod, uint32(r[0]), _MAX_STRING)
 
 		got := ExtendedErrorCode(i).Error()
 		if got != want {

go.mod

@@ -4,9 +4,9 @@ go 1.19
 
 require (
 	github.com/ncruces/julianday v0.1.5
-	github.com/tetratelabs/wazero v1.0.0
+	github.com/tetratelabs/wazero v1.0.2
 	golang.org/x/sync v0.1.0
-	golang.org/x/sys v0.6.0
+	golang.org/x/sys v0.7.0
 )
 
 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 h1:sCE9+mjFex95Ki6hdqwvhyF25x5WslADjDKIFU5BXzI=
-github.com/tetratelabs/wazero v1.0.0/go.mod h1:wYx2gNRg8/WihJfSDxA1TIL8H+GkfLYm+bIfbblu9VQ=
+github.com/tetratelabs/wazero v1.0.2 h1:lpwL5zczFHk2mxKur98035Gig+Z3vd9JURk6lUdZxXY=
+github.com/tetratelabs/wazero v1.0.2/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 v0.6.0 h1:MVltZSvRTcU2ljQOhs94SXPftV6DCNnZViHeQps87pQ=
-golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.7.0 h1:3jlCCIQZPdOYu1h8BkNvLz8Kgwtae2cagcG/VamtZRU=
+golang.org/x/sys v0.7.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

internal/util/error.go

@@ -0,0 +1,42 @@
+package util
+
+import (
+	"fmt"
+	"runtime"
+	"strconv"
+)
+
+type ErrorString string
+
+func (e ErrorString) Error() string { return string(e) }
+
+const (
+	NilErr       = ErrorString("sqlite3: invalid memory address or null pointer dereference")
+	OOMErr       = ErrorString("sqlite3: out of memory")
+	RangeErr     = ErrorString("sqlite3: index out of range")
+	NoNulErr     = ErrorString("sqlite3: missing NUL terminator")
+	NoGlobalErr  = ErrorString("sqlite3: could not find global: ")
+	NoFuncErr    = ErrorString("sqlite3: could not find function: ")
+	BinaryErr    = ErrorString("sqlite3: no SQLite binary embed/set/loaded")
+	TimeErr      = ErrorString("sqlite3: invalid time value")
+	WhenceErr    = ErrorString("sqlite3: invalid whence")
+	OffsetErr    = ErrorString("sqlite3: invalid offset")
+	TailErr      = ErrorString("sqlite3: multiple statements")
+	IsolationErr = ErrorString("sqlite3: unsupported isolation level")
+)
+
+func AssertErr() ErrorString {
+	msg := "sqlite3: assertion failed"
+	if _, file, line, ok := runtime.Caller(1); ok {
+		msg += " (" + file + ":" + strconv.Itoa(line) + ")"
+	}
+	return ErrorString(msg)
+}
+
+func Finalizer[T any](skip int) func(*T) {
+	msg := fmt.Sprintf("sqlite3: %T not closed", new(T))
+	if _, file, line, ok := runtime.Caller(skip + 1); ok && skip >= 0 {
+		msg += " (" + file + ":" + strconv.Itoa(line) + ")"
+	}
+	return func(*T) { panic(ErrorString(msg)) }
+}

internal/util/mem.go

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

internal/util/mem_test.go

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

internal/util/mock.go

@@ -1,4 +1,4 @@
-package sqlite3
+package util
 
 import (
 	"context"
@@ -8,13 +8,9 @@ import (
 	"github.com/tetratelabs/wazero/api"
 )
 
-func init() {
-	Path = "./embed/sqlite3.wasm"
-}
-
-func newMemory(size uint32) memory {
+func NewMockModule(size uint32) api.Module {
 	mem := make(mockMemory, size)
-	return memory{mockModule{&mem}}
+	return mockModule{&mem}
 }
 
 type mockModule struct {
@@ -152,10 +148,6 @@ func (m *mockMemory) Grow(delta uint32) (result uint32, ok bool) {
 	return uint32(prev), true
 }
 
-func (m mockMemory) PageSize() (result uint32) {
-	return uint32(len(m) / 65536)
-}
-
 func (m mockMemory) hasSize(offset uint32, byteCount uint32) bool {
 	return uint64(offset)+uint64(byteCount) <= uint64(len(m))
 }

internal/util/mock_test.go

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

internal/vfs/const.go

@@ -0,0 +1,217 @@
+package vfs
+
+const (
+	_MAX_PATHNAME        = 512
+	_DEFAULT_SECTOR_SIZE = 4096
+)
+
+// https://www.sqlite.org/rescode.html
+type _ErrorCode uint32
+
+const (
+	_OK       _ErrorCode = 0  /* Successful result */
+	_PERM     _ErrorCode = 3  /* Access permission denied */
+	_BUSY     _ErrorCode = 5  /* The database file is locked */
+	_IOERR    _ErrorCode = 10 /* Some kind of disk I/O error occurred */
+	_NOTFOUND _ErrorCode = 12 /* Unknown opcode in sqlite3_file_control() */
+	_CANTOPEN _ErrorCode = 14 /* Unable to open the database file */
+
+	_IOERR_READ              = _IOERR | (1 << 8)
+	_IOERR_SHORT_READ        = _IOERR | (2 << 8)
+	_IOERR_WRITE             = _IOERR | (3 << 8)
+	_IOERR_FSYNC             = _IOERR | (4 << 8)
+	_IOERR_DIR_FSYNC         = _IOERR | (5 << 8)
+	_IOERR_TRUNCATE          = _IOERR | (6 << 8)
+	_IOERR_FSTAT             = _IOERR | (7 << 8)
+	_IOERR_UNLOCK            = _IOERR | (8 << 8)
+	_IOERR_RDLOCK            = _IOERR | (9 << 8)
+	_IOERR_DELETE            = _IOERR | (10 << 8)
+	_IOERR_BLOCKED           = _IOERR | (11 << 8)
+	_IOERR_NOMEM             = _IOERR | (12 << 8)
+	_IOERR_ACCESS            = _IOERR | (13 << 8)
+	_IOERR_CHECKRESERVEDLOCK = _IOERR | (14 << 8)
+	_IOERR_LOCK              = _IOERR | (15 << 8)
+	_IOERR_CLOSE             = _IOERR | (16 << 8)
+	_IOERR_DIR_CLOSE         = _IOERR | (17 << 8)
+	_IOERR_SHMOPEN           = _IOERR | (18 << 8)
+	_IOERR_SHMSIZE           = _IOERR | (19 << 8)
+	_IOERR_SHMLOCK           = _IOERR | (20 << 8)
+	_IOERR_SHMMAP            = _IOERR | (21 << 8)
+	_IOERR_SEEK              = _IOERR | (22 << 8)
+	_IOERR_DELETE_NOENT      = _IOERR | (23 << 8)
+	_IOERR_MMAP              = _IOERR | (24 << 8)
+	_IOERR_GETTEMPPATH       = _IOERR | (25 << 8)
+	_IOERR_CONVPATH          = _IOERR | (26 << 8)
+	_IOERR_VNODE             = _IOERR | (27 << 8)
+	_IOERR_AUTH              = _IOERR | (28 << 8)
+	_IOERR_BEGIN_ATOMIC      = _IOERR | (29 << 8)
+	_IOERR_COMMIT_ATOMIC     = _IOERR | (30 << 8)
+	_IOERR_ROLLBACK_ATOMIC   = _IOERR | (31 << 8)
+	_IOERR_DATA              = _IOERR | (32 << 8)
+	_IOERR_CORRUPTFS         = _IOERR | (33 << 8)
+	_CANTOPEN_NOTEMPDIR      = _CANTOPEN | (1 << 8)
+	_CANTOPEN_ISDIR          = _CANTOPEN | (2 << 8)
+	_CANTOPEN_FULLPATH       = _CANTOPEN | (3 << 8)
+	_CANTOPEN_CONVPATH       = _CANTOPEN | (4 << 8)
+	_CANTOPEN_DIRTYWAL       = _CANTOPEN | (5 << 8) /* Not Used */
+	_CANTOPEN_SYMLINK        = _CANTOPEN | (6 << 8)
+	_OK_SYMLINK              = _OK | (2 << 8) /* internal use only */
+)
+
+// https://www.sqlite.org/c3ref/c_open_autoproxy.html
+type _OpenFlag uint32
+
+const (
+	_OPEN_READONLY      _OpenFlag = 0x00000001 /* Ok for sqlite3_open_v2() */
+	_OPEN_READWRITE     _OpenFlag = 0x00000002 /* Ok for sqlite3_open_v2() */
+	_OPEN_CREATE        _OpenFlag = 0x00000004 /* Ok for sqlite3_open_v2() */
+	_OPEN_DELETEONCLOSE _OpenFlag = 0x00000008 /* VFS only */
+	_OPEN_EXCLUSIVE     _OpenFlag = 0x00000010 /* VFS only */
+	_OPEN_AUTOPROXY     _OpenFlag = 0x00000020 /* VFS only */
+	_OPEN_URI           _OpenFlag = 0x00000040 /* Ok for sqlite3_open_v2() */
+	_OPEN_MEMORY        _OpenFlag = 0x00000080 /* Ok for sqlite3_open_v2() */
+	_OPEN_MAIN_DB       _OpenFlag = 0x00000100 /* VFS only */
+	_OPEN_TEMP_DB       _OpenFlag = 0x00000200 /* VFS only */
+	_OPEN_TRANSIENT_DB  _OpenFlag = 0x00000400 /* VFS only */
+	_OPEN_MAIN_JOURNAL  _OpenFlag = 0x00000800 /* VFS only */
+	_OPEN_TEMP_JOURNAL  _OpenFlag = 0x00001000 /* VFS only */
+	_OPEN_SUBJOURNAL    _OpenFlag = 0x00002000 /* VFS only */
+	_OPEN_SUPER_JOURNAL _OpenFlag = 0x00004000 /* VFS only */
+	_OPEN_NOMUTEX       _OpenFlag = 0x00008000 /* Ok for sqlite3_open_v2() */
+	_OPEN_FULLMUTEX     _OpenFlag = 0x00010000 /* Ok for sqlite3_open_v2() */
+	_OPEN_SHAREDCACHE   _OpenFlag = 0x00020000 /* Ok for sqlite3_open_v2() */
+	_OPEN_PRIVATECACHE  _OpenFlag = 0x00040000 /* Ok for sqlite3_open_v2() */
+	_OPEN_WAL           _OpenFlag = 0x00080000 /* VFS only */
+	_OPEN_NOFOLLOW      _OpenFlag = 0x01000000 /* Ok for sqlite3_open_v2() */
+	_OPEN_EXRESCODE     _OpenFlag = 0x02000000 /* Extended result codes */
+)
+
+// https://www.sqlite.org/c3ref/c_access_exists.html
+type _AccessFlag uint32
+
+const (
+	_ACCESS_EXISTS    _AccessFlag = 0
+	_ACCESS_READWRITE _AccessFlag = 1 /* Used by PRAGMA temp_store_directory */
+	_ACCESS_READ      _AccessFlag = 2 /* Unused */
+)
+
+// https://www.sqlite.org/c3ref/c_sync_dataonly.html
+type _SyncFlag uint32
+
+const (
+	_SYNC_NORMAL   _SyncFlag = 0x00002
+	_SYNC_FULL     _SyncFlag = 0x00003
+	_SYNC_DATAONLY _SyncFlag = 0x00010
+)
+
+// https://www.sqlite.org/c3ref/c_lock_exclusive.html
+type _LockLevel uint32
+
+const (
+	// No locks are held on the database.
+	// The database may be neither read nor written.
+	// Any internally cached data is considered suspect and subject to
+	// verification against the database file before being used.
+	// Other processes can read or write the database as their own locking
+	// states permit.
+	// This is the default state.
+	_LOCK_NONE _LockLevel = 0 /* xUnlock() only */
+
+	// The database may be read but not written.
+	// Any number of processes can hold SHARED locks at the same time,
+	// hence there can be many simultaneous readers.
+	// But no other thread or process is allowed to write to the database file
+	// while one or more SHARED locks are active.
+	_LOCK_SHARED _LockLevel = 1 /* xLock() or xUnlock() */
+
+	// A RESERVED lock means that the process is planning on writing to the
+	// database file at some point in the future but that it is currently just
+	// reading from the file.
+	// Only a single RESERVED lock may be active at one time,
+	// though multiple SHARED locks can coexist with a single RESERVED lock.
+	// RESERVED differs from PENDING in that new SHARED locks can be acquired
+	// while there is a RESERVED lock.
+	_LOCK_RESERVED _LockLevel = 2 /* xLock() only */
+
+	// A PENDING lock means that the process holding the lock wants to write to
+	// the database as soon as possible and is just waiting on all current
+	// SHARED locks to clear so that it can get an EXCLUSIVE lock.
+	// No new SHARED locks are permitted against the database if a PENDING lock
+	// is active, though existing SHARED locks are allowed to continue.
+	_LOCK_PENDING _LockLevel = 3 /* internal use only */
+
+	// An EXCLUSIVE lock is needed in order to write to the database file.
+	// Only one EXCLUSIVE lock is allowed on the file and no other locks of any
+	// kind are allowed to coexist with an EXCLUSIVE lock.
+	// In order to maximize concurrency, SQLite works to minimize the amount of
+	// time that EXCLUSIVE locks are held.
+	_LOCK_EXCLUSIVE _LockLevel = 4 /* xLock() only */
+)
+
+// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html
+type _FcntlOpcode uint32
+
+const (
+	_FCNTL_LOCKSTATE             _FcntlOpcode = 1
+	_FCNTL_GET_LOCKPROXYFILE     _FcntlOpcode = 2
+	_FCNTL_SET_LOCKPROXYFILE     _FcntlOpcode = 3
+	_FCNTL_LAST_ERRNO            _FcntlOpcode = 4
+	_FCNTL_SIZE_HINT             _FcntlOpcode = 5
+	_FCNTL_CHUNK_SIZE            _FcntlOpcode = 6
+	_FCNTL_FILE_POINTER          _FcntlOpcode = 7
+	_FCNTL_SYNC_OMITTED          _FcntlOpcode = 8
+	_FCNTL_WIN32_AV_RETRY        _FcntlOpcode = 9
+	_FCNTL_PERSIST_WAL           _FcntlOpcode = 10
+	_FCNTL_OVERWRITE             _FcntlOpcode = 11
+	_FCNTL_VFSNAME               _FcntlOpcode = 12
+	_FCNTL_POWERSAFE_OVERWRITE   _FcntlOpcode = 13
+	_FCNTL_PRAGMA                _FcntlOpcode = 14
+	_FCNTL_BUSYHANDLER           _FcntlOpcode = 15
+	_FCNTL_TEMPFILENAME          _FcntlOpcode = 16
+	_FCNTL_MMAP_SIZE             _FcntlOpcode = 18
+	_FCNTL_TRACE                 _FcntlOpcode = 19
+	_FCNTL_HAS_MOVED             _FcntlOpcode = 20
+	_FCNTL_SYNC                  _FcntlOpcode = 21
+	_FCNTL_COMMIT_PHASETWO       _FcntlOpcode = 22
+	_FCNTL_WIN32_SET_HANDLE      _FcntlOpcode = 23
+	_FCNTL_WAL_BLOCK             _FcntlOpcode = 24
+	_FCNTL_ZIPVFS                _FcntlOpcode = 25
+	_FCNTL_RBU                   _FcntlOpcode = 26
+	_FCNTL_VFS_POINTER           _FcntlOpcode = 27
+	_FCNTL_JOURNAL_POINTER       _FcntlOpcode = 28
+	_FCNTL_WIN32_GET_HANDLE      _FcntlOpcode = 29
+	_FCNTL_PDB                   _FcntlOpcode = 30
+	_FCNTL_BEGIN_ATOMIC_WRITE    _FcntlOpcode = 31
+	_FCNTL_COMMIT_ATOMIC_WRITE   _FcntlOpcode = 32
+	_FCNTL_ROLLBACK_ATOMIC_WRITE _FcntlOpcode = 33
+	_FCNTL_LOCK_TIMEOUT          _FcntlOpcode = 34
+	_FCNTL_DATA_VERSION          _FcntlOpcode = 35
+	_FCNTL_SIZE_LIMIT            _FcntlOpcode = 36
+	_FCNTL_CKPT_DONE             _FcntlOpcode = 37
+	_FCNTL_RESERVE_BYTES         _FcntlOpcode = 38
+	_FCNTL_CKPT_START            _FcntlOpcode = 39
+	_FCNTL_EXTERNAL_READER       _FcntlOpcode = 40
+	_FCNTL_CKSM_FILE             _FcntlOpcode = 41
+	_FCNTL_RESET_CACHE           _FcntlOpcode = 42
+)
+
+// https://www.sqlite.org/c3ref/c_iocap_atomic.html
+type _DeviceCharacteristic uint32
+
+const (
+	_IOCAP_ATOMIC                _DeviceCharacteristic = 0x00000001
+	_IOCAP_ATOMIC512             _DeviceCharacteristic = 0x00000002
+	_IOCAP_ATOMIC1K              _DeviceCharacteristic = 0x00000004
+	_IOCAP_ATOMIC2K              _DeviceCharacteristic = 0x00000008
+	_IOCAP_ATOMIC4K              _DeviceCharacteristic = 0x00000010
+	_IOCAP_ATOMIC8K              _DeviceCharacteristic = 0x00000020
+	_IOCAP_ATOMIC16K             _DeviceCharacteristic = 0x00000040
+	_IOCAP_ATOMIC32K             _DeviceCharacteristic = 0x00000080
+	_IOCAP_ATOMIC64K             _DeviceCharacteristic = 0x00000100
+	_IOCAP_SAFE_APPEND           _DeviceCharacteristic = 0x00000200
+	_IOCAP_SEQUENTIAL            _DeviceCharacteristic = 0x00000400
+	_IOCAP_UNDELETABLE_WHEN_OPEN _DeviceCharacteristic = 0x00000800
+	_IOCAP_POWERSAFE_OVERWRITE   _DeviceCharacteristic = 0x00001000
+	_IOCAP_IMMUTABLE             _DeviceCharacteristic = 0x00002000
+	_IOCAP_BATCH_ATOMIC          _DeviceCharacteristic = 0x00004000
+)

internal/vfs/func.go

@@ -0,0 +1,78 @@
+package vfs
+
+import (
+	"context"
+
+	"github.com/tetratelabs/wazero"
+	"github.com/tetratelabs/wazero/api"
+)
+
+func registerFunc1[T0, TR ~uint32](mod wazero.HostModuleBuilder, name string, fn func(ctx context.Context, mod api.Module, _ T0) TR) {
+	mod.NewFunctionBuilder().
+		WithGoModuleFunction(api.GoModuleFunc(
+			func(ctx context.Context, mod api.Module, stack []uint64) {
+				stack[0] = uint64(fn(ctx, mod, T0(stack[0])))
+			}),
+			[]api.ValueType{api.ValueTypeI32}, []api.ValueType{api.ValueTypeI32}).
+		Export(name)
+}
+
+func registerFunc2[T0, T1, TR ~uint32](mod wazero.HostModuleBuilder, name string, fn func(ctx context.Context, mod api.Module, _ T0, _ T1) TR) {
+	mod.NewFunctionBuilder().
+		WithGoModuleFunction(api.GoModuleFunc(
+			func(ctx context.Context, mod api.Module, stack []uint64) {
+				stack[0] = uint64(fn(ctx, mod, T0(stack[0]), T1(stack[1])))
+			}),
+			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI32}, []api.ValueType{api.ValueTypeI32}).
+		Export(name)
+}
+
+func registerFunc3[T0, T1, T2, TR ~uint32](mod wazero.HostModuleBuilder, name string, fn func(ctx context.Context, mod api.Module, _ T0, _ T1, _ T2) TR) {
+	mod.NewFunctionBuilder().
+		WithGoModuleFunction(api.GoModuleFunc(
+			func(ctx context.Context, mod api.Module, stack []uint64) {
+				stack[0] = uint64(fn(ctx, mod, T0(stack[0]), T1(stack[1]), T2(stack[2])))
+			}),
+			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32}, []api.ValueType{api.ValueTypeI32}).
+		Export(name)
+}
+
+func registerFunc4[T0, T1, T2, T3, TR ~uint32](mod wazero.HostModuleBuilder, name string, fn func(ctx context.Context, mod api.Module, _ T0, _ T1, _ T2, _ T3) TR) {
+	mod.NewFunctionBuilder().
+		WithGoModuleFunction(api.GoModuleFunc(
+			func(ctx context.Context, mod api.Module, stack []uint64) {
+				stack[0] = uint64(fn(ctx, mod, T0(stack[0]), T1(stack[1]), T2(stack[2]), T3(stack[3])))
+			}),
+			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32}, []api.ValueType{api.ValueTypeI32}).
+		Export(name)
+}
+
+func registerFunc5[T0, T1, T2, T3, T4, TR ~uint32](mod wazero.HostModuleBuilder, name string, fn func(ctx context.Context, mod api.Module, _ T0, _ T1, _ T2, _ T3, _ T4) TR) {
+	mod.NewFunctionBuilder().
+		WithGoModuleFunction(api.GoModuleFunc(
+			func(ctx context.Context, mod api.Module, stack []uint64) {
+				stack[0] = uint64(fn(ctx, mod, T0(stack[0]), T1(stack[1]), T2(stack[2]), T3(stack[3]), T4(stack[4])))
+			}),
+			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32}, []api.ValueType{api.ValueTypeI32}).
+		Export(name)
+}
+
+func registerFuncRW(mod wazero.HostModuleBuilder, name string, fn func(ctx context.Context, mod api.Module, _, _, _ uint32, _ int64) _ErrorCode) {
+	mod.NewFunctionBuilder().
+		WithGoModuleFunction(api.GoModuleFunc(
+			func(ctx context.Context, mod api.Module, stack []uint64) {
+				stack[0] = uint64(fn(ctx, mod, uint32(stack[0]), uint32(stack[1]), uint32(stack[2]), int64(stack[3])))
+			}),
+			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI64}, []api.ValueType{api.ValueTypeI32}).
+		Export(name)
+}
+
+func registerFuncT(mod wazero.HostModuleBuilder, name string, fn func(ctx context.Context, mod api.Module, _ uint32, _ int64) _ErrorCode) {
+	mod.NewFunctionBuilder().
+		WithGoModuleFunction(api.GoModuleFunc(
+			func(ctx context.Context, mod api.Module, stack []uint64) {
+				stack[0] = uint64(fn(ctx, mod, uint32(stack[0]), int64(stack[1])))
+			}),
+			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI64}, []api.ValueType{api.ValueTypeI32}).
+		Export(name)
+}

internal/vfs/tests/mptest/mptest_test.go

@@ -16,13 +16,11 @@ import (
 	"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"
+	"github.com/ncruces/go-sqlite3/internal/vfs"
 )
 
 //go:embed testdata/mptest.wasm
@@ -31,12 +29,6 @@ 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
@@ -48,7 +40,7 @@ func init() {
 
 	rt = wazero.NewRuntime(ctx)
 	wasi_snapshot_preview1.MustInstantiate(ctx, rt)
-	env := vfsNewEnvModuleBuilder(rt)
+	env := vfs.NewEnvModuleBuilder(rt)
 	env.NewFunctionBuilder().WithFunc(system).Export("system")
 	_, err := env.Instantiate(ctx)
 	if err != nil {
@@ -88,7 +80,7 @@ func system(ctx context.Context, mod api.Module, ptr uint32) uint32 {
 
 	cfg := config(ctx).WithArgs(args...)
 	go func() {
-		ctx, vfs := vfsContext(ctx)
+		ctx, vfs := vfs.Context(ctx)
 		rt.InstantiateModule(ctx, module, cfg)
 		vfs.Close()
 	}()
@@ -96,7 +88,7 @@ func system(ctx context.Context, mod api.Module, ptr uint32) uint32 {
 }
 
 func Test_config01(t *testing.T) {
-	ctx, vfs := vfsContext(newContext(t))
+	ctx, vfs := vfs.Context(newContext(t))
 	name := filepath.Join(t.TempDir(), "test.db")
 	cfg := config(ctx).WithArgs("mptest", name, "config01.test")
 	mod, err := rt.InstantiateModule(ctx, module, cfg)
@@ -115,7 +107,7 @@ func Test_config02(t *testing.T) {
 		t.Skip("skipping in CI")
 	}
 
-	ctx, vfs := vfsContext(newContext(t))
+	ctx, vfs := vfs.Context(newContext(t))
 	name := filepath.Join(t.TempDir(), "test.db")
 	cfg := config(ctx).WithArgs("mptest", name, "config02.test")
 	mod, err := rt.InstantiateModule(ctx, module, cfg)
@@ -131,7 +123,7 @@ func Test_crash01(t *testing.T) {
 		t.Skip("skipping in short mode")
 	}
 
-	ctx, vfs := vfsContext(newContext(t))
+	ctx, vfs := vfs.Context(newContext(t))
 	name := filepath.Join(t.TempDir(), "test.db")
 	cfg := config(ctx).WithArgs("mptest", name, "crash01.test")
 	mod, err := rt.InstantiateModule(ctx, module, cfg)
@@ -147,7 +139,7 @@ func Test_multiwrite01(t *testing.T) {
 		t.Skip("skipping in short mode")
 	}
 
-	ctx, vfs := vfsContext(newContext(t))
+	ctx, vfs := vfs.Context(newContext(t))
 	name := filepath.Join(t.TempDir(), "test.db")
 	cfg := config(ctx).WithArgs("mptest", name, "multiwrite01.test")
 	mod, err := rt.InstantiateModule(ctx, module, cfg)

internal/vfs/tests/mptest/testdata/build.sh

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+cd -P -- "$(dirname -- "$0")"
+
+ROOT=../../../../../
+BINARYEN="$ROOT/tools/binaryen-version_112/bin"
+WASI_SDK="$ROOT/tools/wasi-sdk-20.0/bin"
+
+"$WASI_SDK/clang" --target=wasm32-wasi -flto -g0 -O2 \
+  -o mptest.wasm main.c \
+	-I"$ROOT/sqlite3" \
+	-mmutable-globals \
+	-mbulk-memory -mreference-types \
+	-mnontrapping-fptoint -msign-ext \
+	-Wl,--stack-first \
+	-Wl,--import-undefined \
+	-D_HAVE_SQLITE_CONFIG_H \
+	-DSQLITE_DEFAULT_SYNCHRONOUS=0 \
+	-DSQLITE_DEFAULT_LOCKING_MODE=0 \
+	-DHAVE_USLEEP -DSQLITE_NO_SYNC \
+	-DSQLITE_THREADSAFE=0 -DSQLITE_OMIT_LOAD_EXTENSION \
+	-D_WASI_EMULATED_GETPID -lwasi-emulated-getpid
+
+"$BINARYEN/wasm-opt" -g -O2 mptest.wasm -o mptest.tmp \
+	--enable-multivalue --enable-mutable-globals \
+	--enable-bulk-memory --enable-reference-types \
+	--enable-nontrapping-float-to-int --enable-sign-ext
+mv mptest.tmp mptest.wasm

internal/vfs/tests/mptest/testdata/main.c

@@ -4,7 +4,6 @@
 #include "sqlite3.c"
 //
 #include "os.c"
-#include "qsort.c"
 
 sqlite3_destructor_type malloc_destructor = &free;
 size_t sqlite3_interrupt_offset = offsetof(sqlite3, u1.isInterrupted);

internal/vfs/tests/mptest/testdata/mptest.wasm

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:37ceeed293b9f09e9770b40eda3f625447f5a3a74208709886d4411d12f93414
+size 1486113

internal/vfs/tests/speedtest1/speedtest1_test.go

@@ -13,23 +13,16 @@ import (
 	"testing"
 
 	_ "embed"
-	_ "unsafe"
 
 	"github.com/tetratelabs/wazero"
 	"github.com/tetratelabs/wazero/imports/wasi_snapshot_preview1"
 
-	_ "github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/vfs"
 )
 
 //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
@@ -42,7 +35,7 @@ func init() {
 
 	rt = wazero.NewRuntime(ctx)
 	wasi_snapshot_preview1.MustInstantiate(ctx, rt)
-	env := vfsNewEnvModuleBuilder(rt)
+	env := vfs.NewEnvModuleBuilder(rt)
 	_, err := env.Instantiate(ctx)
 	if err != nil {
 		panic(err)
@@ -74,7 +67,7 @@ func TestMain(m *testing.M) {
 
 func Benchmark_speedtest1(b *testing.B) {
 	output.Reset()
-	ctx, vfs := vfsContext(context.Background())
+	ctx, vfs := vfs.Context(context.Background())
 	name := filepath.Join(b.TempDir(), "test.db")
 	args := append(options, "--size", strconv.Itoa(b.N), name)
 	cfg := wazero.NewModuleConfig().

internal/vfs/tests/speedtest1/testdata/build.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+cd -P -- "$(dirname -- "$0")"
+
+ROOT=../../../../../
+BINARYEN="$ROOT/tools/binaryen-version_112/bin"
+WASI_SDK="$ROOT/tools/wasi-sdk-20.0/bin"
+
+"$WASI_SDK/clang" --target=wasm32-wasi -flto -g0 -O2 \
+	-o speedtest1.wasm main.c \
+	-I"$ROOT/sqlite3" \
+	-mmutable-globals \
+	-mbulk-memory -mreference-types \
+	-mnontrapping-fptoint -msign-ext \
+	-Wl,--stack-first \
+	-Wl,--import-undefined \
+	-D_HAVE_SQLITE_CONFIG_H
+
+"$BINARYEN/wasm-opt" -g -O2 speedtest1.wasm -o speedtest1.tmp \
+	--enable-multivalue --enable-mutable-globals \
+	--enable-bulk-memory --enable-reference-types \
+	--enable-nontrapping-float-to-int --enable-sign-ext
+mv speedtest1.tmp speedtest1.wasm

internal/vfs/tests/speedtest1/testdata/main.c

@@ -4,7 +4,6 @@
 #include "sqlite3.c"
 //
 #include "os.c"
-#include "qsort.c"
 
 sqlite3_destructor_type malloc_destructor = &free;
 size_t sqlite3_interrupt_offset = offsetof(sqlite3, u1.isInterrupted);

internal/vfs/tests/speedtest1/testdata/speedtest1.wasm

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:8167119c344a68217b0301e2e8c288f2e75611d296d7822f841b65911da0275c
+size 1520569

internal/vfs/vfs.go

@@ -0,0 +1,399 @@
+package vfs
+
+import (
+	"context"
+	"crypto/rand"
+	"errors"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"runtime"
+	"time"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
+	"github.com/ncruces/julianday"
+	"github.com/tetratelabs/wazero"
+	"github.com/tetratelabs/wazero/api"
+)
+
+func Instantiate(ctx context.Context, r wazero.Runtime) {
+	env := NewEnvModuleBuilder(r)
+	_, err := env.Instantiate(ctx)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func NewEnvModuleBuilder(r wazero.Runtime) wazero.HostModuleBuilder {
+	env := r.NewHostModuleBuilder("env")
+	registerFuncT(env, "os_localtime", vfsLocaltime)
+	registerFunc3(env, "os_randomness", vfsRandomness)
+	registerFunc2(env, "os_sleep", vfsSleep)
+	registerFunc2(env, "os_current_time", vfsCurrentTime)
+	registerFunc2(env, "os_current_time_64", vfsCurrentTime64)
+	registerFunc4(env, "os_full_pathname", vfsFullPathname)
+	registerFunc3(env, "os_delete", vfsDelete)
+	registerFunc4(env, "os_access", vfsAccess)
+	registerFunc5(env, "os_open", vfsOpen)
+	registerFunc1(env, "os_close", vfsClose)
+	registerFuncRW(env, "os_read", vfsRead)
+	registerFuncRW(env, "os_write", vfsWrite)
+	registerFuncT(env, "os_truncate", vfsTruncate)
+	registerFunc2(env, "os_sync", vfsSync)
+	registerFunc2(env, "os_file_size", vfsFileSize)
+	registerFunc3(env, "os_file_control", vfsFileControl)
+	registerFunc1(env, "os_sector_size", vfsSectorSize)
+	registerFunc1(env, "os_device_characteristics", vfsDeviceCharacteristics)
+	registerFunc2(env, "os_lock", vfsLock)
+	registerFunc2(env, "os_unlock", vfsUnlock)
+	registerFunc2(env, "os_check_reserved_lock", vfsCheckReservedLock)
+	return env
+}
+
+type vfsKey struct{}
+type vfsState struct {
+	files []vfsFile
+}
+
+func Context(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.File != nil {
+			f.Close()
+		}
+	}
+	vfs.files = nil
+	return nil
+}
+
+func vfsLocaltime(ctx context.Context, mod api.Module, pTm uint32, t int64) _ErrorCode {
+	tm := time.Unix(t, 0)
+	var isdst int
+	if tm.IsDST() {
+		isdst = 1
+	}
+
+	const size = 32 / 8
+	// https://pubs.opengroup.org/onlinepubs/7908799/xsh/time.h.html
+	util.WriteUint32(mod, pTm+0*size, uint32(tm.Second()))
+	util.WriteUint32(mod, pTm+1*size, uint32(tm.Minute()))
+	util.WriteUint32(mod, pTm+2*size, uint32(tm.Hour()))
+	util.WriteUint32(mod, pTm+3*size, uint32(tm.Day()))
+	util.WriteUint32(mod, pTm+4*size, uint32(tm.Month()-time.January))
+	util.WriteUint32(mod, pTm+5*size, uint32(tm.Year()-1900))
+	util.WriteUint32(mod, pTm+6*size, uint32(tm.Weekday()-time.Sunday))
+	util.WriteUint32(mod, pTm+7*size, uint32(tm.YearDay()-1))
+	util.WriteUint32(mod, pTm+8*size, uint32(isdst))
+	return _OK
+}
+
+func vfsRandomness(ctx context.Context, mod api.Module, pVfs, nByte, zByte uint32) uint32 {
+	mem := util.View(mod, zByte, uint64(nByte))
+	n, _ := rand.Reader.Read(mem)
+	return uint32(n)
+}
+
+func vfsSleep(ctx context.Context, mod api.Module, pVfs, nMicro uint32) _ErrorCode {
+	time.Sleep(time.Duration(nMicro) * time.Microsecond)
+	return _OK
+}
+
+func vfsCurrentTime(ctx context.Context, mod api.Module, pVfs, prNow uint32) _ErrorCode {
+	day := julianday.Float(time.Now())
+	util.WriteFloat64(mod, prNow, day)
+	return _OK
+}
+
+func vfsCurrentTime64(ctx context.Context, mod api.Module, pVfs, piNow uint32) _ErrorCode {
+	day, nsec := julianday.Date(time.Now())
+	msec := day*86_400_000 + nsec/1_000_000
+	util.WriteUint64(mod, piNow, uint64(msec))
+	return _OK
+}
+
+func vfsFullPathname(ctx context.Context, mod api.Module, pVfs, zRelative, nFull, zFull uint32) _ErrorCode {
+	rel := util.ReadString(mod, zRelative, _MAX_PATHNAME)
+	abs, err := filepath.Abs(rel)
+	if err != nil {
+		return _CANTOPEN_FULLPATH
+	}
+
+	size := uint64(len(abs) + 1)
+	if size > uint64(nFull) {
+		return _CANTOPEN_FULLPATH
+	}
+	mem := util.View(mod, zFull, size)
+	mem[len(abs)] = 0
+	copy(mem, abs)
+
+	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 _CANTOPEN_FULLPATH
+}
+
+func vfsDelete(ctx context.Context, mod api.Module, pVfs, zPath, syncDir uint32) _ErrorCode {
+	path := util.ReadString(mod, zPath, _MAX_PATHNAME)
+	err := os.Remove(path)
+	if errors.Is(err, fs.ErrNotExist) {
+		return _IOERR_DELETE_NOENT
+	}
+	if err != nil {
+		return _IOERR_DELETE
+	}
+	if runtime.GOOS != "windows" && syncDir != 0 {
+		f, err := os.Open(filepath.Dir(path))
+		if err != nil {
+			return _OK
+		}
+		defer f.Close()
+		err = osSync(f, false, false)
+		if err != nil {
+			return _IOERR_DIR_FSYNC
+		}
+	}
+	return _OK
+}
+
+func vfsAccess(ctx context.Context, mod api.Module, pVfs, zPath uint32, flags _AccessFlag, pResOut uint32) _ErrorCode {
+	path := util.ReadString(mod, zPath, _MAX_PATHNAME)
+	err := osAccess(path, flags)
+
+	var res uint32
+	var rc _ErrorCode
+	if flags == _ACCESS_EXISTS {
+		switch {
+		case err == nil:
+			res = 1
+		case errors.Is(err, fs.ErrNotExist):
+			res = 0
+		default:
+			rc = _IOERR_ACCESS
+		}
+	} else {
+		switch {
+		case err == nil:
+			res = 1
+		case errors.Is(err, fs.ErrPermission):
+			res = 0
+		default:
+			rc = _IOERR_ACCESS
+		}
+	}
+
+	util.WriteUint32(mod, pResOut, res)
+	return rc
+}
+
+func vfsOpen(ctx context.Context, mod api.Module, pVfs, zName, pFile uint32, flags _OpenFlag, pOutFlags uint32) _ErrorCode {
+	var oflags int
+	if flags&_OPEN_EXCLUSIVE != 0 {
+		oflags |= os.O_EXCL
+	}
+	if flags&_OPEN_CREATE != 0 {
+		oflags |= os.O_CREATE
+	}
+	if flags&_OPEN_READONLY != 0 {
+		oflags |= os.O_RDONLY
+	}
+	if flags&_OPEN_READWRITE != 0 {
+		oflags |= os.O_RDWR
+	}
+
+	var err error
+	var f *os.File
+	if zName == 0 {
+		f, err = os.CreateTemp("", "*.db")
+	} else {
+		name := util.ReadString(mod, zName, _MAX_PATHNAME)
+		f, err = osOpenFile(name, oflags, 0666)
+	}
+	if err != nil {
+		return _CANTOPEN
+	}
+
+	if flags&_OPEN_DELETEONCLOSE != 0 {
+		os.Remove(f.Name())
+	}
+
+	file := openVFSFile(ctx, mod, pFile, f)
+	file.psow = true
+	file.readOnly = flags&_OPEN_READONLY != 0
+	file.syncDir = runtime.GOOS != "windows" &&
+		flags&(_OPEN_CREATE) != 0 &&
+		flags&(_OPEN_MAIN_JOURNAL|_OPEN_SUPER_JOURNAL|_OPEN_WAL) != 0
+
+	if pOutFlags != 0 {
+		util.WriteUint32(mod, pOutFlags, uint32(flags))
+	}
+	return _OK
+}
+
+func vfsClose(ctx context.Context, mod api.Module, pFile uint32) _ErrorCode {
+	err := closeVFSFile(ctx, mod, pFile)
+	if err != nil {
+		return _IOERR_CLOSE
+	}
+	return _OK
+}
+
+func vfsRead(ctx context.Context, mod api.Module, pFile, zBuf, iAmt uint32, iOfst int64) _ErrorCode {
+	buf := util.View(mod, zBuf, uint64(iAmt))
+
+	file := getVFSFile(ctx, mod, pFile)
+	n, err := file.ReadAt(buf, iOfst)
+	if n == int(iAmt) {
+		return _OK
+	}
+	if n == 0 && err != io.EOF {
+		return _IOERR_READ
+	}
+	for i := range buf[n:] {
+		buf[n+i] = 0
+	}
+	return _IOERR_SHORT_READ
+}
+
+func vfsWrite(ctx context.Context, mod api.Module, pFile, zBuf, iAmt uint32, iOfst int64) _ErrorCode {
+	buf := util.View(mod, zBuf, uint64(iAmt))
+
+	file := getVFSFile(ctx, mod, pFile)
+	_, err := file.WriteAt(buf, iOfst)
+	if err != nil {
+		return _IOERR_WRITE
+	}
+	return _OK
+}
+
+func vfsTruncate(ctx context.Context, mod api.Module, pFile uint32, nByte int64) _ErrorCode {
+	file := getVFSFile(ctx, mod, pFile)
+	err := file.Truncate(nByte)
+	if err != nil {
+		return _IOERR_TRUNCATE
+	}
+	return _OK
+}
+
+func vfsSync(ctx context.Context, mod api.Module, pFile uint32, flags _SyncFlag) _ErrorCode {
+	dataonly := (flags & _SYNC_DATAONLY) != 0
+	fullsync := (flags & 0x0f) == _SYNC_FULL
+
+	file := getVFSFile(ctx, mod, pFile)
+	err := osSync(file.File, fullsync, dataonly)
+	if err != nil {
+		return _IOERR_FSYNC
+	}
+	if runtime.GOOS != "windows" && file.syncDir {
+		file.syncDir = false
+		f, err := os.Open(filepath.Dir(file.Name()))
+		if err != nil {
+			return _OK
+		}
+		defer f.Close()
+		err = osSync(f, false, false)
+		if err != nil {
+			return _IOERR_DIR_FSYNC
+		}
+	}
+	return _OK
+}
+
+func vfsFileSize(ctx context.Context, mod api.Module, pFile, pSize uint32) _ErrorCode {
+	file := getVFSFile(ctx, mod, pFile)
+	off, err := file.Seek(0, io.SeekEnd)
+	if err != nil {
+		return _IOERR_SEEK
+	}
+
+	util.WriteUint64(mod, pSize, uint64(off))
+	return _OK
+}
+
+func vfsFileControl(ctx context.Context, mod api.Module, pFile uint32, op _FcntlOpcode, pArg uint32) _ErrorCode {
+	switch op {
+	case _FCNTL_LOCKSTATE:
+		util.WriteUint32(mod, pArg, uint32(getVFSFile(ctx, mod, pFile).lock))
+		return _OK
+	case _FCNTL_LOCK_TIMEOUT:
+		file := getVFSFile(ctx, mod, pFile)
+		millis := file.lockTimeout.Milliseconds()
+		file.lockTimeout = time.Duration(util.ReadUint32(mod, pArg)) * time.Millisecond
+		util.WriteUint32(mod, pArg, uint32(millis))
+		return _OK
+	case _FCNTL_POWERSAFE_OVERWRITE:
+		file := getVFSFile(ctx, mod, pFile)
+		switch util.ReadUint32(mod, pArg) {
+		case 0:
+			file.psow = false
+		case 1:
+			file.psow = true
+		default:
+			if file.psow {
+				util.WriteUint32(mod, pArg, 1)
+			} else {
+				util.WriteUint32(mod, pArg, 0)
+			}
+		}
+	case _FCNTL_SIZE_HINT:
+		return vfsSizeHint(ctx, mod, pFile, pArg)
+	case _FCNTL_HAS_MOVED:
+		return vfsFileMoved(ctx, mod, pFile, pArg)
+	}
+	// Consider also implementing these opcodes (in use by SQLite):
+	//  _FCNTL_BUSYHANDLER
+	//  _FCNTL_COMMIT_PHASETWO
+	//  _FCNTL_PDB
+	//  _FCNTL_PRAGMA
+	//  _FCNTL_SYNC
+	return _NOTFOUND
+}
+
+func vfsSectorSize(ctx context.Context, mod api.Module, pFile uint32) uint32 {
+	return _DEFAULT_SECTOR_SIZE
+}
+
+func vfsDeviceCharacteristics(ctx context.Context, mod api.Module, pFile uint32) _DeviceCharacteristic {
+	file := getVFSFile(ctx, mod, pFile)
+	if file.psow {
+		return _IOCAP_POWERSAFE_OVERWRITE
+	}
+	return 0
+}
+
+func vfsSizeHint(ctx context.Context, mod api.Module, pFile, pArg uint32) _ErrorCode {
+	file := getVFSFile(ctx, mod, pFile)
+	size := util.ReadUint64(mod, pArg)
+	err := osAllocate(file.File, int64(size))
+	if err != nil {
+		return _IOERR_TRUNCATE
+	}
+	return _OK
+}
+
+func vfsFileMoved(ctx context.Context, mod api.Module, pFile, pResOut uint32) _ErrorCode {
+	file := getVFSFile(ctx, mod, pFile)
+	fi, err := file.Stat()
+	if err != nil {
+		return _IOERR_FSTAT
+	}
+	pi, err := os.Stat(file.Name())
+	if err != nil && !errors.Is(err, fs.ErrNotExist) {
+		return _IOERR_FSTAT
+	}
+	var res uint32
+	if !os.SameFile(fi, pi) {
+		res = 1
+	}
+	util.WriteUint32(mod, pResOut, res)
+	return _OK
+}

internal/vfs/vfs_file.go

@@ -0,0 +1,54 @@
+package vfs
+
+import (
+	"context"
+	"os"
+	"time"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
+	"github.com/tetratelabs/wazero/api"
+)
+
+type vfsFile struct {
+	*os.File
+	lockTimeout time.Duration
+	lock        _LockLevel
+	psow        bool
+	syncDir     bool
+	readOnly    bool
+}
+
+func newVFSFile(vfs *vfsState, file *os.File) uint32 {
+	// Find an empty slot.
+	for id, f := range vfs.files {
+		if f.File == nil {
+			vfs.files[id] = vfsFile{File: file}
+			return uint32(id)
+		}
+	}
+
+	// Add a new slot.
+	vfs.files = append(vfs.files, vfsFile{File: file})
+	return uint32(len(vfs.files) - 1)
+}
+
+func getVFSFile(ctx context.Context, mod api.Module, pFile uint32) *vfsFile {
+	vfs := ctx.Value(vfsKey{}).(*vfsState)
+	id := util.ReadUint32(mod, pFile+4)
+	return &vfs.files[id]
+}
+
+func openVFSFile(ctx context.Context, mod api.Module, pFile uint32, file *os.File) *vfsFile {
+	vfs := ctx.Value(vfsKey{}).(*vfsState)
+	id := newVFSFile(vfs, file)
+	util.WriteUint32(mod, pFile+4, id)
+	return &vfs.files[id]
+}
+
+func closeVFSFile(ctx context.Context, mod api.Module, pFile uint32) error {
+	vfs := ctx.Value(vfsKey{}).(*vfsState)
+	id := util.ReadUint32(mod, pFile+4)
+	file := vfs.files[id]
+	vfs.files[id] = vfsFile{}
+	return file.Close()
+}

internal/vfs/vfs_lock.go

@@ -0,0 +1,168 @@
+package vfs
+
+import (
+	"context"
+	"os"
+	"time"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
+	"github.com/tetratelabs/wazero/api"
+)
+
+const (
+	_PENDING_BYTE  = 0x40000000
+	_RESERVED_BYTE = (_PENDING_BYTE + 1)
+	_SHARED_FIRST  = (_PENDING_BYTE + 2)
+	_SHARED_SIZE   = 510
+)
+
+func vfsLock(ctx context.Context, mod api.Module, pFile uint32, eLock _LockLevel) _ErrorCode {
+	// Argument check. SQLite never explicitly requests a pending lock.
+	if eLock != _LOCK_SHARED && eLock != _LOCK_RESERVED && eLock != _LOCK_EXCLUSIVE {
+		panic(util.AssertErr())
+	}
+
+	file := getVFSFile(ctx, mod, pFile)
+
+	switch {
+	case file.lock < _LOCK_NONE || file.lock > _LOCK_EXCLUSIVE:
+		// Connection state check.
+		panic(util.AssertErr())
+	case file.lock == _LOCK_NONE && eLock > _LOCK_SHARED:
+		// We never move from unlocked to anything higher than a shared lock.
+		panic(util.AssertErr())
+	case file.lock != _LOCK_SHARED && eLock == _LOCK_RESERVED:
+		// A shared lock is always held when a reserved lock is requested.
+		panic(util.AssertErr())
+	}
+
+	// If we already have an equal or more restrictive lock, do nothing.
+	if file.lock >= eLock {
+		return _OK
+	}
+
+	// Do not allow any kind of write-lock on a read-only database.
+	if file.readOnly && eLock >= _LOCK_RESERVED {
+		return _IOERR_LOCK
+	}
+
+	switch eLock {
+	case _LOCK_SHARED:
+		// Must be unlocked to get SHARED.
+		if file.lock != _LOCK_NONE {
+			panic(util.AssertErr())
+		}
+		if rc := osGetSharedLock(file.File, file.lockTimeout); rc != _OK {
+			return rc
+		}
+		file.lock = _LOCK_SHARED
+		return _OK
+
+	case _LOCK_RESERVED:
+		// Must be SHARED to get RESERVED.
+		if file.lock != _LOCK_SHARED {
+			panic(util.AssertErr())
+		}
+		if rc := osGetReservedLock(file.File, file.lockTimeout); rc != _OK {
+			return rc
+		}
+		file.lock = _LOCK_RESERVED
+		return _OK
+
+	case _LOCK_EXCLUSIVE:
+		// Must be SHARED, RESERVED or PENDING to get EXCLUSIVE.
+		if file.lock <= _LOCK_NONE || file.lock >= _LOCK_EXCLUSIVE {
+			panic(util.AssertErr())
+		}
+		// A PENDING lock is needed before acquiring an EXCLUSIVE lock.
+		if file.lock < _LOCK_PENDING {
+			if rc := osGetPendingLock(file.File); rc != _OK {
+				return rc
+			}
+			file.lock = _LOCK_PENDING
+		}
+		if rc := osGetExclusiveLock(file.File, file.lockTimeout); rc != _OK {
+			return rc
+		}
+		file.lock = _LOCK_EXCLUSIVE
+		return _OK
+
+	default:
+		panic(util.AssertErr())
+	}
+}
+
+func vfsUnlock(ctx context.Context, mod api.Module, pFile uint32, eLock _LockLevel) _ErrorCode {
+	// Argument check.
+	if eLock != _LOCK_NONE && eLock != _LOCK_SHARED {
+		panic(util.AssertErr())
+	}
+
+	file := getVFSFile(ctx, mod, pFile)
+
+	// Connection state check.
+	if file.lock < _LOCK_NONE || file.lock > _LOCK_EXCLUSIVE {
+		panic(util.AssertErr())
+	}
+
+	// If we don't have a more restrictive lock, do nothing.
+	if file.lock <= eLock {
+		return _OK
+	}
+
+	switch eLock {
+	case _LOCK_SHARED:
+		if rc := osDowngradeLock(file.File, file.lock); rc != _OK {
+			return rc
+		}
+		file.lock = _LOCK_SHARED
+		return _OK
+
+	case _LOCK_NONE:
+		rc := osReleaseLock(file.File, file.lock)
+		file.lock = _LOCK_NONE
+		return rc
+
+	default:
+		panic(util.AssertErr())
+	}
+}
+
+func vfsCheckReservedLock(ctx context.Context, mod api.Module, pFile, pResOut uint32) _ErrorCode {
+	file := getVFSFile(ctx, mod, pFile)
+
+	// Connection state check.
+	if file.lock < _LOCK_NONE || file.lock > _LOCK_EXCLUSIVE {
+		panic(util.AssertErr())
+	}
+
+	var locked bool
+	var rc _ErrorCode
+	if file.lock >= _LOCK_RESERVED {
+		locked = true
+	} else {
+		locked, rc = osCheckReservedLock(file.File)
+	}
+
+	var res uint32
+	if locked {
+		res = 1
+	}
+	util.WriteUint32(mod, pResOut, res)
+	return rc
+}
+
+func osGetReservedLock(file *os.File, timeout time.Duration) _ErrorCode {
+	// Acquire the RESERVED lock.
+	return osWriteLock(file, _RESERVED_BYTE, 1, timeout)
+}
+
+func osGetPendingLock(file *os.File) _ErrorCode {
+	// Acquire the PENDING lock.
+	return osWriteLock(file, _PENDING_BYTE, 1, 0)
+}
+
+func osCheckReservedLock(file *os.File) (bool, _ErrorCode) {
+	// Test the RESERVED lock.
+	return osCheckLock(file, _RESERVED_BYTE, 1)
+}

internal/vfs/vfs_lock_test.go

@@ -1,4 +1,4 @@
-package sqlite3
+package vfs
 
 import (
 	"context"
@@ -6,6 +6,8 @@ import (
 	"path/filepath"
 	"runtime"
 	"testing"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
 )
 
 func Test_vfsLock(t *testing.T) {
@@ -37,133 +39,133 @@ func Test_vfsLock(t *testing.T) {
 		pFile2  = 16
 		pOutput = 32
 	)
-	mem := newMemory(128)
-	ctx, vfs := vfsContext(context.TODO())
+	mod := util.NewMockModule(128)
+	ctx, vfs := Context(context.TODO())
 	defer vfs.Close()
 
-	vfsFile.Open(ctx, mem.mod, pFile1, file1)
-	vfsFile.Open(ctx, mem.mod, pFile2, file2)
+	openVFSFile(ctx, mod, pFile1, file1)
+	openVFSFile(ctx, mod, pFile2, file2)
 
-	rc := vfsCheckReservedLock(ctx, mem.mod, pFile1, pOutput)
+	rc := vfsCheckReservedLock(ctx, mod, pFile1, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(pOutput); got != 0 {
+	if got := util.ReadUint32(mod, pOutput); got != 0 {
 		t.Error("file was locked")
 	}
-	rc = vfsCheckReservedLock(ctx, mem.mod, pFile2, pOutput)
+	rc = vfsCheckReservedLock(ctx, mod, pFile2, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(pOutput); got != 0 {
+	if got := util.ReadUint32(mod, pOutput); got != 0 {
 		t.Error("file was locked")
 	}
 
-	rc = vfsLock(ctx, mem.mod, pFile2, _SHARED_LOCK)
+	rc = vfsLock(ctx, mod, pFile2, _LOCK_SHARED)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
 
-	rc = vfsCheckReservedLock(ctx, mem.mod, pFile1, pOutput)
+	rc = vfsCheckReservedLock(ctx, mod, pFile1, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(pOutput); got != 0 {
+	if got := util.ReadUint32(mod, pOutput); got != 0 {
 		t.Error("file was locked")
 	}
-	rc = vfsCheckReservedLock(ctx, mem.mod, pFile2, pOutput)
+	rc = vfsCheckReservedLock(ctx, mod, pFile2, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(pOutput); got != 0 {
+	if got := util.ReadUint32(mod, pOutput); got != 0 {
 		t.Error("file was locked")
 	}
 
-	rc = vfsLock(ctx, mem.mod, pFile2, _RESERVED_LOCK)
+	rc = vfsLock(ctx, mod, pFile2, _LOCK_RESERVED)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	rc = vfsLock(ctx, mem.mod, pFile2, _SHARED_LOCK)
+	rc = vfsLock(ctx, mod, pFile2, _LOCK_SHARED)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
 
-	rc = vfsCheckReservedLock(ctx, mem.mod, pFile1, pOutput)
+	rc = vfsCheckReservedLock(ctx, mod, pFile1, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(pOutput); got == 0 {
+	if got := util.ReadUint32(mod, pOutput); got == 0 {
 		t.Error("file wasn't locked")
 	}
-	rc = vfsCheckReservedLock(ctx, mem.mod, pFile2, pOutput)
+	rc = vfsCheckReservedLock(ctx, mod, pFile2, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(pOutput); got == 0 {
+	if got := util.ReadUint32(mod, pOutput); got == 0 {
 		t.Error("file wasn't locked")
 	}
 
-	rc = vfsLock(ctx, mem.mod, pFile2, _EXCLUSIVE_LOCK)
+	rc = vfsLock(ctx, mod, pFile2, _LOCK_EXCLUSIVE)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
 
-	rc = vfsCheckReservedLock(ctx, mem.mod, pFile1, pOutput)
+	rc = vfsCheckReservedLock(ctx, mod, pFile1, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(pOutput); got == 0 {
+	if got := util.ReadUint32(mod, pOutput); got == 0 {
 		t.Error("file wasn't locked")
 	}
-	rc = vfsCheckReservedLock(ctx, mem.mod, pFile2, pOutput)
+	rc = vfsCheckReservedLock(ctx, mod, pFile2, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(pOutput); got == 0 {
+	if got := util.ReadUint32(mod, pOutput); got == 0 {
 		t.Error("file wasn't locked")
 	}
 
-	rc = vfsLock(ctx, mem.mod, pFile1, _SHARED_LOCK)
+	rc = vfsLock(ctx, mod, pFile1, _LOCK_SHARED)
 	if rc == _OK {
 		t.Fatal("returned", rc)
 	}
 
-	rc = vfsCheckReservedLock(ctx, mem.mod, pFile1, pOutput)
+	rc = vfsCheckReservedLock(ctx, mod, pFile1, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(pOutput); got == 0 {
+	if got := util.ReadUint32(mod, pOutput); got == 0 {
 		t.Error("file wasn't locked")
 	}
-	rc = vfsCheckReservedLock(ctx, mem.mod, pFile2, pOutput)
+	rc = vfsCheckReservedLock(ctx, mod, pFile2, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(pOutput); got == 0 {
+	if got := util.ReadUint32(mod, pOutput); got == 0 {
 		t.Error("file wasn't locked")
 	}
 
-	rc = vfsUnlock(ctx, mem.mod, pFile2, _SHARED_LOCK)
+	rc = vfsUnlock(ctx, mod, pFile2, _LOCK_SHARED)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
 
-	rc = vfsCheckReservedLock(ctx, mem.mod, pFile1, pOutput)
+	rc = vfsCheckReservedLock(ctx, mod, pFile1, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(pOutput); got != 0 {
+	if got := util.ReadUint32(mod, pOutput); got != 0 {
 		t.Error("file was locked")
 	}
-	rc = vfsCheckReservedLock(ctx, mem.mod, pFile2, pOutput)
+	rc = vfsCheckReservedLock(ctx, mod, pFile2, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(pOutput); got != 0 {
+	if got := util.ReadUint32(mod, pOutput); got != 0 {
 		t.Error("file was locked")
 	}
 
-	rc = vfsLock(ctx, mem.mod, pFile1, _SHARED_LOCK)
+	rc = vfsLock(ctx, mod, pFile1, _LOCK_SHARED)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}

internal/vfs/vfs_os_bsd.go

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

internal/vfs/vfs_os_darwin.go

@@ -1,6 +1,6 @@
 //go:build !sqlite3_bsd
 
-package sqlite3
+package vfs
 
 import (
 	"io"
@@ -23,14 +23,14 @@ type flocktimeout_t struct {
 	timeout unix.Timespec
 }
 
-func (vfsOSMethods) Sync(file *os.File, fullsync, dataonly bool) error {
+func osSync(file *os.File, fullsync, dataonly bool) error {
 	if fullsync {
 		return file.Sync()
 	}
 	return unix.Fsync(int(file.Fd()))
 }
 
-func (vfsOSMethods) Allocate(file *os.File, size int64) error {
+func osAllocate(file *os.File, size int64) error {
 	off, err := file.Seek(0, io.SeekEnd)
 	if err != nil {
 		return err
@@ -57,19 +57,19 @@ func (vfsOSMethods) Allocate(file *os.File, size int64) error {
 	return file.Truncate(size)
 }
 
-func (vfsOSMethods) unlock(file *os.File, start, len int64) xErrorCode {
+func osUnlock(file *os.File, start, len int64) _ErrorCode {
 	err := unix.FcntlFlock(file.Fd(), _F_OFD_SETLK, &unix.Flock_t{
 		Type:  unix.F_UNLCK,
 		Start: start,
 		Len:   len,
 	})
 	if err != nil {
-		return IOERR_UNLOCK
+		return _IOERR_UNLOCK
 	}
 	return _OK
 }
 
-func (vfsOSMethods) lock(file *os.File, typ int16, start, len int64, timeout time.Duration, def xErrorCode) xErrorCode {
+func osLock(file *os.File, typ int16, start, len int64, timeout time.Duration, def _ErrorCode) _ErrorCode {
 	lock := flocktimeout_t{fl: unix.Flock_t{
 		Type:  typ,
 		Start: start,
@@ -82,25 +82,25 @@ func (vfsOSMethods) lock(file *os.File, typ int16, start, len int64, timeout tim
 		lock.timeout = unix.NsecToTimespec(int64(timeout / time.Nanosecond))
 		err = unix.FcntlFlock(file.Fd(), _F_OFD_SETLKWTIMEOUT, &lock.fl)
 	}
-	return vfsOS.lockErrorCode(err, def)
+	return osLockErrorCode(err, def)
 }
 
-func (vfsOSMethods) readLock(file *os.File, start, len int64, timeout time.Duration) xErrorCode {
-	return vfsOS.lock(file, unix.F_RDLCK, start, len, timeout, IOERR_RDLOCK)
+func osReadLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
+	return osLock(file, unix.F_RDLCK, start, len, timeout, _IOERR_RDLOCK)
 }
 
-func (vfsOSMethods) writeLock(file *os.File, start, len int64, timeout time.Duration) xErrorCode {
-	return vfsOS.lock(file, unix.F_WRLCK, start, len, timeout, IOERR_LOCK)
+func osWriteLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
+	return osLock(file, unix.F_WRLCK, start, len, timeout, _IOERR_LOCK)
 }
 
-func (vfsOSMethods) checkLock(file *os.File, start, len int64) (bool, xErrorCode) {
+func osCheckLock(file *os.File, start, len int64) (bool, _ErrorCode) {
 	lock := unix.Flock_t{
 		Type:  unix.F_RDLCK,
 		Start: start,
 		Len:   len,
 	}
 	if unix.FcntlFlock(file.Fd(), _F_OFD_GETLK, &lock) != nil {
-		return false, IOERR_CHECKRESERVEDLOCK
+		return false, _IOERR_CHECKRESERVEDLOCK
 	}
 	return lock.Type != unix.F_UNLCK, _OK
 }

internal/vfs/vfs_os_linux.go

@@ -1,4 +1,4 @@
-package sqlite3
+package vfs
 
 import (
 	"os"
@@ -6,7 +6,7 @@ import (
 	"golang.org/x/sys/unix"
 )
 
-func (vfsOSMethods) Sync(file *os.File, fullsync, dataonly bool) error {
+func osSync(file *os.File, fullsync, dataonly bool) error {
 	if dataonly {
 		_, _, err := unix.Syscall(unix.SYS_FDATASYNC, file.Fd(), 0, 0)
 		if err != 0 {
@@ -17,7 +17,7 @@ func (vfsOSMethods) Sync(file *os.File, fullsync, dataonly bool) error {
 	return file.Sync()
 }
 
-func (vfsOSMethods) Allocate(file *os.File, size int64) error {
+func osAllocate(file *os.File, size int64) error {
 	if size == 0 {
 		return nil
 	}

internal/vfs/vfs_os_ofd.go

@@ -1,6 +1,6 @@
 //go:build linux || illumos
 
-package sqlite3
+package vfs
 
 import (
 	"os"
@@ -9,19 +9,19 @@ import (
 	"golang.org/x/sys/unix"
 )
 
-func (vfsOSMethods) unlock(file *os.File, start, len int64) xErrorCode {
+func osUnlock(file *os.File, start, len int64) _ErrorCode {
 	err := unix.FcntlFlock(file.Fd(), unix.F_OFD_SETLK, &unix.Flock_t{
 		Type:  unix.F_UNLCK,
 		Start: start,
 		Len:   len,
 	})
 	if err != nil {
-		return IOERR_UNLOCK
+		return _IOERR_UNLOCK
 	}
 	return _OK
 }
 
-func (vfsOSMethods) lock(file *os.File, typ int16, start, len int64, timeout time.Duration, def xErrorCode) xErrorCode {
+func osLock(file *os.File, typ int16, start, len int64, timeout time.Duration, def _ErrorCode) _ErrorCode {
 	lock := unix.Flock_t{
 		Type:  typ,
 		Start: start,
@@ -39,25 +39,25 @@ func (vfsOSMethods) lock(file *os.File, typ int16, start, len int64, timeout tim
 		timeout -= time.Millisecond
 		time.Sleep(time.Millisecond)
 	}
-	return vfsOS.lockErrorCode(err, def)
+	return osLockErrorCode(err, def)
 }
 
-func (vfsOSMethods) readLock(file *os.File, start, len int64, timeout time.Duration) xErrorCode {
-	return vfsOS.lock(file, unix.F_RDLCK, start, len, timeout, IOERR_RDLOCK)
+func osReadLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
+	return osLock(file, unix.F_RDLCK, start, len, timeout, _IOERR_RDLOCK)
 }
 
-func (vfsOSMethods) writeLock(file *os.File, start, len int64, timeout time.Duration) xErrorCode {
-	return vfsOS.lock(file, unix.F_WRLCK, start, len, timeout, IOERR_LOCK)
+func osWriteLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
+	return osLock(file, unix.F_WRLCK, start, len, timeout, _IOERR_LOCK)
 }
 
-func (vfsOSMethods) checkLock(file *os.File, start, len int64) (bool, xErrorCode) {
+func osCheckLock(file *os.File, start, len int64) (bool, _ErrorCode) {
 	lock := unix.Flock_t{
 		Type:  unix.F_RDLCK,
 		Start: start,
 		Len:   len,
 	}
 	if unix.FcntlFlock(file.Fd(), unix.F_OFD_GETLK, &lock) != nil {
-		return false, IOERR_CHECKRESERVEDLOCK
+		return false, _IOERR_CHECKRESERVEDLOCK
 	}
 	return lock.Type != unix.F_UNLCK, _OK
 }

internal/vfs/vfs_os_other.go

@@ -1,17 +1,17 @@
 //go:build !linux && (!darwin || sqlite3_bsd)
 
-package sqlite3
+package vfs
 
 import (
 	"io"
 	"os"
 )
 
-func (vfsOSMethods) Sync(file *os.File, fullsync, dataonly bool) error {
+func osSync(file *os.File, fullsync, dataonly bool) error {
 	return file.Sync()
 }
 
-func (vfsOSMethods) Allocate(file *os.File, size int64) error {
+func osAllocate(file *os.File, size int64) error {
 	off, err := file.Seek(0, io.SeekEnd)
 	if err != nil {
 		return err

internal/vfs/vfs_os_unix.go

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

internal/vfs/vfs_os_windows.go

@@ -1,4 +1,4 @@
-package sqlite3
+package vfs
 
 import (
 	"io/fs"
@@ -9,12 +9,12 @@ import (
 	"golang.org/x/sys/windows"
 )
 
-// OpenFile is a simplified copy of [os.openFileNolog]
+// osOpenFile is a simplified copy of [os.openFileNolog]
 // that uses syscall.FILE_SHARE_DELETE.
 // https://go.dev/src/os/file_windows.go
 //
 // See: https://go.dev/issue/32088
-func (vfsOSMethods) OpenFile(name string, flag int, perm fs.FileMode) (*os.File, error) {
+func osOpenFile(name string, flag int, perm fs.FileMode) (*os.File, error) {
 	if name == "" {
 		return nil, &os.PathError{Op: "open", Path: name, Err: syscall.ENOENT}
 	}
@@ -25,7 +25,7 @@ func (vfsOSMethods) OpenFile(name string, flag int, perm fs.FileMode) (*os.File,
 	return os.NewFile(uintptr(r), name), nil
 }
 
-func (vfsOSMethods) Access(path string, flags _AccessFlag) error {
+func osAccess(path string, flags _AccessFlag) error {
 	fi, err := os.Stat(path)
 	if err != nil {
 		return err
@@ -47,88 +47,88 @@ func (vfsOSMethods) Access(path string, flags _AccessFlag) error {
 	return nil
 }
 
-func (vfsOSMethods) GetSharedLock(file *os.File, timeout time.Duration) xErrorCode {
+func osGetSharedLock(file *os.File, timeout time.Duration) _ErrorCode {
 	// Acquire the PENDING lock temporarily before acquiring a new SHARED lock.
-	rc := vfsOS.readLock(file, _PENDING_BYTE, 1, timeout)
+	rc := osReadLock(file, _PENDING_BYTE, 1, timeout)
 
 	if rc == _OK {
 		// Acquire the SHARED lock.
-		rc = vfsOS.readLock(file, _SHARED_FIRST, _SHARED_SIZE, 0)
+		rc = osReadLock(file, _SHARED_FIRST, _SHARED_SIZE, 0)
 
 		// Release the PENDING lock.
-		vfsOS.unlock(file, _PENDING_BYTE, 1)
+		osUnlock(file, _PENDING_BYTE, 1)
 	}
 	return rc
 }
 
-func (vfsOSMethods) GetExclusiveLock(file *os.File, timeout time.Duration) xErrorCode {
+func osGetExclusiveLock(file *os.File, timeout time.Duration) _ErrorCode {
 	if timeout == 0 {
 		timeout = time.Millisecond
 	}
 
 	// Release the SHARED lock.
-	vfsOS.unlock(file, _SHARED_FIRST, _SHARED_SIZE)
+	osUnlock(file, _SHARED_FIRST, _SHARED_SIZE)
 
 	// Acquire the EXCLUSIVE lock.
-	rc := vfsOS.writeLock(file, _SHARED_FIRST, _SHARED_SIZE, timeout)
+	rc := osWriteLock(file, _SHARED_FIRST, _SHARED_SIZE, timeout)
 
 	if rc != _OK {
 		// Reacquire the SHARED lock.
-		vfsOS.readLock(file, _SHARED_FIRST, _SHARED_SIZE, 0)
+		osReadLock(file, _SHARED_FIRST, _SHARED_SIZE, 0)
 	}
 	return rc
 }
 
-func (vfsOSMethods) DowngradeLock(file *os.File, state vfsLockState) xErrorCode {
-	if state >= _EXCLUSIVE_LOCK {
+func osDowngradeLock(file *os.File, state _LockLevel) _ErrorCode {
+	if state >= _LOCK_EXCLUSIVE {
 		// Release the SHARED lock.
-		vfsOS.unlock(file, _SHARED_FIRST, _SHARED_SIZE)
+		osUnlock(file, _SHARED_FIRST, _SHARED_SIZE)
 
 		// Reacquire the SHARED lock.
-		if rc := vfsOS.readLock(file, _SHARED_FIRST, _SHARED_SIZE, 0); rc != _OK {
+		if rc := osReadLock(file, _SHARED_FIRST, _SHARED_SIZE, 0); rc != _OK {
 			// This should never happen.
 			// We should always be able to reacquire the read lock.
-			return IOERR_RDLOCK
+			return _IOERR_RDLOCK
 		}
 	}
 
 	// Release the PENDING and RESERVED locks.
-	if state >= _RESERVED_LOCK {
-		vfsOS.unlock(file, _RESERVED_BYTE, 1)
+	if state >= _LOCK_RESERVED {
+		osUnlock(file, _RESERVED_BYTE, 1)
 	}
-	if state >= _PENDING_LOCK {
-		vfsOS.unlock(file, _PENDING_BYTE, 1)
+	if state >= _LOCK_PENDING {
+		osUnlock(file, _PENDING_BYTE, 1)
 	}
 	return _OK
 }
 
-func (vfsOSMethods) ReleaseLock(file *os.File, state vfsLockState) xErrorCode {
+func osReleaseLock(file *os.File, state _LockLevel) _ErrorCode {
 	// Release all locks.
-	if state >= _RESERVED_LOCK {
-		vfsOS.unlock(file, _RESERVED_BYTE, 1)
+	if state >= _LOCK_RESERVED {
+		osUnlock(file, _RESERVED_BYTE, 1)
 	}
-	if state >= _SHARED_LOCK {
-		vfsOS.unlock(file, _SHARED_FIRST, _SHARED_SIZE)
+	if state >= _LOCK_SHARED {
+		osUnlock(file, _SHARED_FIRST, _SHARED_SIZE)
 	}
-	if state >= _PENDING_LOCK {
-		vfsOS.unlock(file, _PENDING_BYTE, 1)
+	if state >= _LOCK_PENDING {
+		osUnlock(file, _PENDING_BYTE, 1)
 	}
 	return _OK
 }
 
-func (vfsOSMethods) unlock(file *os.File, start, len uint32) xErrorCode {
+func osUnlock(file *os.File, start, len uint32) _ErrorCode {
 	err := windows.UnlockFileEx(windows.Handle(file.Fd()),
 		0, len, 0, &windows.Overlapped{Offset: start})
 	if err == windows.ERROR_NOT_LOCKED {
 		return _OK
 	}
 	if err != nil {
-		return IOERR_UNLOCK
+		return _IOERR_UNLOCK
 	}
 	return _OK
 }
 
-func (vfsOSMethods) lock(file *os.File, flags, start, len uint32, timeout time.Duration, def xErrorCode) xErrorCode {
+func osLock(file *os.File, flags, start, len uint32, timeout time.Duration, def _ErrorCode) _ErrorCode {
 	var err error
 	for {
 		err = windows.LockFileEx(windows.Handle(file.Fd()), flags,
@@ -142,35 +142,35 @@ func (vfsOSMethods) lock(file *os.File, flags, start, len uint32, timeout time.D
 		timeout -= time.Millisecond
 		time.Sleep(time.Millisecond)
 	}
-	return vfsOS.lockErrorCode(err, def)
+	return osLockErrorCode(err, def)
 }
 
-func (vfsOSMethods) readLock(file *os.File, start, len uint32, timeout time.Duration) xErrorCode {
-	return vfsOS.lock(file,
+func osReadLock(file *os.File, start, len uint32, timeout time.Duration) _ErrorCode {
+	return osLock(file,
 		windows.LOCKFILE_FAIL_IMMEDIATELY,
-		start, len, timeout, IOERR_RDLOCK)
+		start, len, timeout, _IOERR_RDLOCK)
 }
 
-func (vfsOSMethods) writeLock(file *os.File, start, len uint32, timeout time.Duration) xErrorCode {
-	return vfsOS.lock(file,
+func osWriteLock(file *os.File, start, len uint32, timeout time.Duration) _ErrorCode {
+	return osLock(file,
 		windows.LOCKFILE_FAIL_IMMEDIATELY|windows.LOCKFILE_EXCLUSIVE_LOCK,
-		start, len, timeout, IOERR_LOCK)
+		start, len, timeout, _IOERR_LOCK)
 }
 
-func (vfsOSMethods) checkLock(file *os.File, start, len uint32) (bool, xErrorCode) {
-	rc := vfsOS.lock(file,
+func osCheckLock(file *os.File, start, len uint32) (bool, _ErrorCode) {
+	rc := osLock(file,
 		windows.LOCKFILE_FAIL_IMMEDIATELY,
-		start, len, 0, IOERR_CHECKRESERVEDLOCK)
-	if rc == xErrorCode(BUSY) {
+		start, len, 0, _IOERR_CHECKRESERVEDLOCK)
+	if rc == _BUSY {
 		return true, _OK
 	}
 	if rc == _OK {
-		vfsOS.unlock(file, start, len)
+		osUnlock(file, start, len)
 	}
 	return false, rc
 }
 
-func (vfsOSMethods) lockErrorCode(err error, def xErrorCode) xErrorCode {
+func osLockErrorCode(err error, def _ErrorCode) _ErrorCode {
 	if err == nil {
 		return _OK
 	}
@@ -181,7 +181,7 @@ func (vfsOSMethods) lockErrorCode(err error, def xErrorCode) xErrorCode {
 			windows.ERROR_LOCK_VIOLATION,
 			windows.ERROR_IO_PENDING,
 			windows.ERROR_OPERATION_ABORTED:
-			return xErrorCode(BUSY)
+			return _BUSY
 		}
 	}
 	return def

internal/vfs/vfs_test.go

@@ -1,4 +1,4 @@
-package sqlite3
+package vfs
 
 import (
 	"bytes"
@@ -11,66 +11,67 @@ import (
 	"testing"
 	"time"
 
+	"github.com/ncruces/go-sqlite3/internal/util"
 	"github.com/ncruces/julianday"
 )
 
 func Test_vfsLocaltime(t *testing.T) {
-	mem := newMemory(128)
+	mod := util.NewMockModule(128)
 	ctx := context.TODO()
 
-	rc := vfsLocaltime(ctx, mem.mod, 4, 0)
+	tm := time.Now()
+	rc := vfsLocaltime(ctx, mod, 4, tm.Unix())
 	if rc != 0 {
 		t.Fatal("returned", rc)
 	}
 
-	epoch := time.Unix(0, 0)
-	if s := mem.readUint32(4 + 0*4); int(s) != epoch.Second() {
+	if s := util.ReadUint32(mod, 4+0*4); int(s) != tm.Second() {
 		t.Error("wrong second")
 	}
-	if m := mem.readUint32(4 + 1*4); int(m) != epoch.Minute() {
+	if m := util.ReadUint32(mod, 4+1*4); int(m) != tm.Minute() {
 		t.Error("wrong minute")
 	}
-	if h := mem.readUint32(4 + 2*4); int(h) != epoch.Hour() {
+	if h := util.ReadUint32(mod, 4+2*4); int(h) != tm.Hour() {
 		t.Error("wrong hour")
 	}
-	if d := mem.readUint32(4 + 3*4); int(d) != epoch.Day() {
+	if d := util.ReadUint32(mod, 4+3*4); int(d) != tm.Day() {
 		t.Error("wrong day")
 	}
-	if m := mem.readUint32(4 + 4*4); time.Month(1+m) != epoch.Month() {
+	if m := util.ReadUint32(mod, 4+4*4); time.Month(1+m) != tm.Month() {
 		t.Error("wrong month")
 	}
-	if y := mem.readUint32(4 + 5*4); 1900+int(y) != epoch.Year() {
+	if y := util.ReadUint32(mod, 4+5*4); 1900+int(y) != tm.Year() {
 		t.Error("wrong year")
 	}
-	if w := mem.readUint32(4 + 6*4); time.Weekday(w) != epoch.Weekday() {
+	if w := util.ReadUint32(mod, 4+6*4); time.Weekday(w) != tm.Weekday() {
 		t.Error("wrong weekday")
 	}
-	if d := mem.readUint32(4 + 7*4); int(d) != epoch.YearDay()-1 {
+	if d := util.ReadUint32(mod, 4+7*4); int(d) != tm.YearDay()-1 {
 		t.Error("wrong yearday")
 	}
 }
 
 func Test_vfsRandomness(t *testing.T) {
-	mem := newMemory(128)
+	mod := util.NewMockModule(128)
 	ctx := context.TODO()
 
-	rc := vfsRandomness(ctx, mem.mod, 0, 16, 4)
+	rc := vfsRandomness(ctx, mod, 0, 16, 4)
 	if rc != 16 {
 		t.Fatal("returned", rc)
 	}
 
 	var zero [16]byte
-	if got := mem.view(4, 16); bytes.Equal(got, zero[:]) {
+	if got := util.View(mod, 4, 16); bytes.Equal(got, zero[:]) {
 		t.Fatal("all zero")
 	}
 }
 
 func Test_vfsSleep(t *testing.T) {
-	mem := newMemory(128)
+	mod := util.NewMockModule(128)
 	ctx := context.TODO()
 
 	now := time.Now()
-	rc := vfsSleep(ctx, mem.mod, 0, 123456)
+	rc := vfsSleep(ctx, mod, 0, 123456)
 	if rc != 0 {
 		t.Fatal("returned", rc)
 	}
@@ -82,56 +83,56 @@ func Test_vfsSleep(t *testing.T) {
 }
 
 func Test_vfsCurrentTime(t *testing.T) {
-	mem := newMemory(128)
+	mod := util.NewMockModule(128)
 	ctx := context.TODO()
 
 	now := time.Now()
-	rc := vfsCurrentTime(ctx, mem.mod, 0, 4)
+	rc := vfsCurrentTime(ctx, mod, 0, 4)
 	if rc != 0 {
 		t.Fatal("returned", rc)
 	}
 
 	want := julianday.Float(now)
-	if got := mem.readFloat64(4); float32(got) != float32(want) {
+	if got := util.ReadFloat64(mod, 4); float32(got) != float32(want) {
 		t.Errorf("got %v, want %v", got, want)
 	}
 }
 
 func Test_vfsCurrentTime64(t *testing.T) {
-	mem := newMemory(128)
+	mod := util.NewMockModule(128)
 	ctx := context.TODO()
 
 	now := time.Now()
 	time.Sleep(time.Millisecond)
-	rc := vfsCurrentTime64(ctx, mem.mod, 0, 4)
+	rc := vfsCurrentTime64(ctx, mod, 0, 4)
 	if rc != 0 {
 		t.Fatal("returned", rc)
 	}
 
 	day, nsec := julianday.Date(now)
 	want := day*86_400_000 + nsec/1_000_000
-	if got := mem.readUint64(4); float32(got) != float32(want) {
+	if got := util.ReadUint64(mod, 4); float32(got) != float32(want) {
 		t.Errorf("got %v, want %v", got, want)
 	}
 }
 
 func Test_vfsFullPathname(t *testing.T) {
-	mem := newMemory(128 + _MAX_PATHNAME)
-	mem.writeString(4, ".")
+	mod := util.NewMockModule(128 + _MAX_PATHNAME)
+	util.WriteString(mod, 4, ".")
 	ctx := context.TODO()
 
-	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(ctx, mod, 0, 4, 0, 8)
+	if rc != _CANTOPEN_FULLPATH {
+		t.Errorf("returned %d, want %d", rc, _CANTOPEN_FULLPATH)
 	}
 
-	rc = vfsFullPathname(ctx, mem.mod, 0, 4, _MAX_PATHNAME, 8)
+	rc = vfsFullPathname(ctx, mod, 0, 4, _MAX_PATHNAME, 8)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
 
 	want, _ := filepath.Abs(".")
-	if got := mem.readString(8, _MAX_PATHNAME); got != want {
+	if got := util.ReadString(mod, 8, _MAX_PATHNAME); got != want {
 		t.Errorf("got %v, want %v", got, want)
 	}
 }
@@ -145,11 +146,11 @@ func Test_vfsDelete(t *testing.T) {
 	}
 	file.Close()
 
-	mem := newMemory(128 + _MAX_PATHNAME)
-	mem.writeString(4, name)
+	mod := util.NewMockModule(128 + _MAX_PATHNAME)
+	util.WriteString(mod, 4, name)
 	ctx := context.TODO()
 
-	rc := vfsDelete(ctx, mem.mod, 0, 4, 1)
+	rc := vfsDelete(ctx, mod, 0, 4, 1)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
@@ -158,8 +159,8 @@ func Test_vfsDelete(t *testing.T) {
 		t.Fatal("did not delete the file")
 	}
 
-	rc = vfsDelete(ctx, mem.mod, 0, 4, 1)
-	if rc != uint32(IOERR_DELETE_NOENT) {
+	rc = vfsDelete(ctx, mod, 0, 4, 1)
+	if rc != _IOERR_DELETE_NOENT {
 		t.Fatal("returned", rc)
 	}
 }
@@ -176,99 +177,99 @@ func Test_vfsAccess(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	mem := newMemory(128 + _MAX_PATHNAME)
-	mem.writeString(8, dir)
+	mod := util.NewMockModule(128 + _MAX_PATHNAME)
+	util.WriteString(mod, 8, dir)
 	ctx := context.TODO()
 
-	rc := vfsAccess(ctx, mem.mod, 0, 8, _ACCESS_EXISTS, 4)
+	rc := vfsAccess(ctx, mod, 0, 8, _ACCESS_EXISTS, 4)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(4); got != 1 {
+	if got := util.ReadUint32(mod, 4); got != 1 {
 		t.Error("directory did not exist")
 	}
 
-	rc = vfsAccess(ctx, mem.mod, 0, 8, _ACCESS_READWRITE, 4)
+	rc = vfsAccess(ctx, mod, 0, 8, _ACCESS_READWRITE, 4)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(4); got != 1 {
+	if got := util.ReadUint32(mod, 4); got != 1 {
 		t.Error("can't access directory")
 	}
 
-	mem.writeString(8, file)
-	rc = vfsAccess(ctx, mem.mod, 0, 8, _ACCESS_READWRITE, 4)
+	util.WriteString(mod, 8, file)
+	rc = vfsAccess(ctx, mod, 0, 8, _ACCESS_READWRITE, 4)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(4); got != 0 {
+	if got := util.ReadUint32(mod, 4); got != 0 {
 		t.Error("can access file")
 	}
 }
 
 func Test_vfsFile(t *testing.T) {
-	mem := newMemory(128)
-	ctx, vfs := vfsContext(context.TODO())
+	mod := util.NewMockModule(128)
+	ctx, vfs := Context(context.TODO())
 	defer vfs.Close()
 
 	// Open a temporary file.
-	rc := vfsOpen(ctx, mem.mod, 0, 0, 4, OPEN_CREATE|OPEN_EXCLUSIVE|OPEN_READWRITE|OPEN_DELETEONCLOSE, 0)
+	rc := vfsOpen(ctx, mod, 0, 0, 4, _OPEN_CREATE|_OPEN_EXCLUSIVE|_OPEN_READWRITE|_OPEN_DELETEONCLOSE, 0)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
 
 	// Write stuff.
 	text := "Hello world!"
-	mem.writeString(16, text)
-	rc = vfsWrite(ctx, mem.mod, 4, 16, uint32(len(text)), 0)
+	util.WriteString(mod, 16, text)
+	rc = vfsWrite(ctx, mod, 4, 16, uint32(len(text)), 0)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
 
 	// Check file size.
-	rc = vfsFileSize(ctx, mem.mod, 4, 16)
+	rc = vfsFileSize(ctx, mod, 4, 16)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(16); got != uint32(len(text)) {
+	if got := util.ReadUint32(mod, 16); got != uint32(len(text)) {
 		t.Errorf("got %d", got)
 	}
 
 	// Partial read at offset.
-	rc = vfsRead(ctx, mem.mod, 4, 16, uint32(len(text)), 4)
-	if rc != uint32(IOERR_SHORT_READ) {
+	rc = vfsRead(ctx, mod, 4, 16, uint32(len(text)), 4)
+	if rc != _IOERR_SHORT_READ {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readString(16, 64); got != text[4:] {
+	if got := util.ReadString(mod, 16, 64); got != text[4:] {
 		t.Errorf("got %q", got)
 	}
 
 	// Truncate the file.
-	rc = vfsTruncate(ctx, mem.mod, 4, 4)
+	rc = vfsTruncate(ctx, mod, 4, 4)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
 
 	// Check file size.
-	rc = vfsFileSize(ctx, mem.mod, 4, 16)
+	rc = vfsFileSize(ctx, mod, 4, 16)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(16); got != 4 {
+	if got := util.ReadUint32(mod, 16); got != 4 {
 		t.Errorf("got %d", got)
 	}
 
 	// Read at offset.
-	rc = vfsRead(ctx, mem.mod, 4, 32, 4, 0)
+	rc = vfsRead(ctx, mod, 4, 32, 4, 0)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readString(32, 64); got != text[:4] {
+	if got := util.ReadString(mod, 32, 64); got != text[:4] {
 		t.Errorf("got %q", got)
 	}
 
 	// Close the file.
-	rc = vfsClose(ctx, mem.mod, 4)
+	rc = vfsClose(ctx, mod, 4)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}

mem.go

@@ -1,135 +0,0 @@
-package sqlite3
-
-import (
-	"bytes"
-	"math"
-
-	"github.com/tetratelabs/wazero/api"
-)
-
-type memory struct {
-	mod api.Module
-}
-
-func (m memory) view(ptr uint32, size uint64) []byte {
-	if ptr == 0 {
-		panic(nilErr)
-	}
-	if size > math.MaxUint32 {
-		panic(rangeErr)
-	}
-	buf, ok := m.mod.Memory().Read(ptr, uint32(size))
-	if !ok {
-		panic(rangeErr)
-	}
-	return buf
-}
-
-func (m memory) 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)
-	}
-	v, ok := m.mod.Memory().ReadUint32Le(ptr)
-	if !ok {
-		panic(rangeErr)
-	}
-	return v
-}
-
-func (m memory) writeUint32(ptr uint32, v uint32) {
-	if ptr == 0 {
-		panic(nilErr)
-	}
-	ok := m.mod.Memory().WriteUint32Le(ptr, v)
-	if !ok {
-		panic(rangeErr)
-	}
-}
-
-func (m memory) readUint64(ptr uint32) uint64 {
-	if ptr == 0 {
-		panic(nilErr)
-	}
-	v, ok := m.mod.Memory().ReadUint64Le(ptr)
-	if !ok {
-		panic(rangeErr)
-	}
-	return v
-}
-
-func (m memory) writeUint64(ptr uint32, v uint64) {
-	if ptr == 0 {
-		panic(nilErr)
-	}
-	ok := m.mod.Memory().WriteUint64Le(ptr, v)
-	if !ok {
-		panic(rangeErr)
-	}
-}
-
-func (m memory) readFloat64(ptr uint32) float64 {
-	return math.Float64frombits(m.readUint64(ptr))
-}
-
-func (m memory) writeFloat64(ptr uint32, v float64) {
-	m.writeUint64(ptr, math.Float64bits(v))
-}
-
-func (m memory) readString(ptr, maxlen uint32) string {
-	if ptr == 0 {
-		panic(nilErr)
-	}
-	switch maxlen {
-	case 0:
-		return ""
-	case math.MaxUint32:
-		// avoid overflow
-	default:
-		maxlen = maxlen + 1
-	}
-	mem := m.mod.Memory()
-	buf, ok := mem.Read(ptr, maxlen)
-	if !ok {
-		buf, ok = mem.Read(ptr, mem.Size()-ptr)
-		if !ok {
-			panic(rangeErr)
-		}
-	}
-	if i := bytes.IndexByte(buf, 0); i < 0 {
-		panic(noNulErr)
-	} else {
-		return string(buf[:i])
-	}
-}
-
-func (m memory) writeBytes(ptr uint32, b []byte) {
-	buf := m.view(ptr, uint64(len(b)))
-	copy(buf, b)
-}
-
-func (m memory) writeString(ptr uint32, s string) {
-	buf := m.view(ptr, uint64(len(s)+1))
-	buf[len(s)] = 0
-	copy(buf, s)
-}

mem_test.go

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

module.go

@@ -8,6 +8,8 @@ import (
 	"os"
 	"sync"
 
+	"github.com/ncruces/go-sqlite3/internal/util"
+	"github.com/ncruces/go-sqlite3/internal/vfs"
 	"github.com/tetratelabs/wazero"
 	"github.com/tetratelabs/wazero/api"
 )
@@ -24,10 +26,10 @@ var (
 )
 
 var sqlite3 struct {
-	once     sync.Once
 	runtime  wazero.Runtime
 	compiled wazero.CompiledModule
 	err      error
+	once     sync.Once
 }
 
 func instantiateModule() (*module, error) {
@@ -38,7 +40,7 @@ func instantiateModule() (*module, error) {
 		return nil, sqlite3.err
 	}
 
-	cfg := wazero.NewModuleConfig().WithStartFunctions("_initialize")
+	cfg := wazero.NewModuleConfig()
 
 	mod, err := sqlite3.runtime.InstantiateModule(ctx, sqlite3.compiled, cfg)
 	if err != nil {
@@ -50,7 +52,7 @@ func instantiateModule() (*module, error) {
 func compileModule() {
 	ctx := context.Background()
 	sqlite3.runtime = wazero.NewRuntime(ctx)
-	vfsInstantiate(ctx, sqlite3.runtime)
+	vfs.Instantiate(ctx, sqlite3.runtime)
 
 	bin := Binary
 	if bin == nil && Path != "" {
@@ -60,7 +62,7 @@ func compileModule() {
 		}
 	}
 	if bin == nil {
-		sqlite3.err = binaryErr
+		sqlite3.err = util.BinaryErr
 		return
 	}
 
@@ -69,38 +71,39 @@ func compileModule() {
 
 type module struct {
 	ctx context.Context
-	mem memory
-	api sqliteAPI
+	mod api.Module
 	vfs io.Closer
+	api sqliteAPI
+	arg []uint64
 }
 
 func newModule(mod api.Module) (m *module, err error) {
 	m = &module{}
-	m.mem = memory{mod}
-	m.ctx, m.vfs = vfsContext(context.Background())
+	m.mod = mod
+	m.ctx, m.vfs = vfs.Context(context.Background())
 
 	getFun := func(name string) api.Function {
 		f := mod.ExportedFunction(name)
 		if f == nil {
-			err = noFuncErr + errorString(name)
+			err = util.NoFuncErr + util.ErrorString(name)
 			return nil
 		}
 		return f
 	}
 
 	getVal := func(name string) uint32 {
-		global := mod.ExportedGlobal(name)
-		if global == nil {
-			err = noGlobalErr + errorString(name)
+		g := mod.ExportedGlobal(name)
+		if g == nil {
+			err = util.NoGlobalErr + util.ErrorString(name)
 			return 0
 		}
-		return m.mem.readUint32(uint32(global.Get()))
+		return util.ReadUint32(mod, uint32(g.Get()))
 	}
 
 	m.api = sqliteAPI{
 		free:            getFun("free"),
 		malloc:          getFun("malloc"),
-		destructor:      uint64(getVal("malloc_destructor")),
+		destructor:      getVal("malloc_destructor"),
 		errcode:         getFun("sqlite3_errcode"),
 		errstr:          getFun("sqlite3_errstr"),
 		errmsg:          getFun("sqlite3_errmsg"),
@@ -154,7 +157,7 @@ func newModule(mod api.Module) (m *module, err error) {
 }
 
 func (m *module) close() error {
-	err := m.mem.mod.Close(m.ctx)
+	err := m.mod.Close(m.ctx)
 	m.vfs.Close()
 	return err
 }
@@ -167,19 +170,19 @@ func (m *module) error(rc uint64, handle uint32, sql ...string) error {
 	err := Error{code: rc}
 
 	if err.Code() == NOMEM || err.ExtendedCode() == IOERR_NOMEM {
-		panic(oomErr)
+		panic(util.OOMErr)
 	}
 
 	var r []uint64
 
 	r = m.call(m.api.errstr, rc)
 	if r != nil {
-		err.str = m.mem.readString(uint32(r[0]), _MAX_STRING)
+		err.str = util.ReadString(m.mod, 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)
+		err.msg = util.ReadString(m.mod, uint32(r[0]), _MAX_STRING)
 	}
 
 	if sql != nil {
@@ -197,7 +200,8 @@ func (m *module) error(rc uint64, handle uint32, sql ...string) error {
 }
 
 func (m *module) call(fn api.Function, params ...uint64) []uint64 {
-	r, err := fn.Call(m.ctx, params...)
+	m.arg = append(m.arg[:0], params...)
+	r, err := fn.Call(m.ctx, m.arg...)
 	if err != nil {
 		// The module closed or panicked; release resources.
 		m.vfs.Close()
@@ -215,12 +219,12 @@ func (m *module) free(ptr uint32) {
 
 func (m *module) new(size uint64) uint32 {
 	if size > _MAX_ALLOCATION_SIZE {
-		panic(oomErr)
+		panic(util.OOMErr)
 	}
 	r := m.call(m.api.malloc, size)
 	ptr := uint32(r[0])
 	if ptr == 0 && size != 0 {
-		panic(oomErr)
+		panic(util.OOMErr)
 	}
 	return ptr
 }
@@ -230,13 +234,13 @@ func (m *module) newBytes(b []byte) uint32 {
 		return 0
 	}
 	ptr := m.new(uint64(len(b)))
-	m.mem.writeBytes(ptr, b)
+	util.WriteBytes(m.mod, ptr, b)
 	return ptr
 }
 
 func (m *module) newString(s string) uint32 {
 	ptr := m.new(uint64(len(s) + 1))
-	m.mem.writeString(ptr, s)
+	util.WriteString(m.mod, ptr, s)
 	return ptr
 }
 
@@ -250,10 +254,10 @@ func (m *module) newArena(size uint64) arena {
 
 type arena struct {
 	m    *module
+	ptrs []uint32
 	base uint32
 	next uint32
 	size uint32
-	ptrs []uint32
 }
 
 func (a *arena) free() {
@@ -286,14 +290,13 @@ func (a *arena) new(size uint64) uint32 {
 
 func (a *arena) string(s string) uint32 {
 	ptr := a.new(uint64(len(s) + 1))
-	a.m.mem.writeString(ptr, s)
+	util.WriteString(a.m.mod, ptr, s)
 	return ptr
 }
 
 type sqliteAPI struct {
 	free            api.Function
 	malloc          api.Function
-	destructor      uint64
 	errcode         api.Function
 	errstr          api.Function
 	errmsg          api.Function
@@ -338,5 +341,6 @@ type sqliteAPI struct {
 	backupFinish    api.Function
 	backupRemaining api.Function
 	backupPageCount api.Function
+	destructor      uint32
 	interrupt       uint32
 }

module_test.go

@@ -4,8 +4,14 @@ import (
 	"bytes"
 	"math"
 	"testing"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
 )
 
+func init() {
+	Path = "./embed/sqlite3.wasm"
+}
+
 func TestConn_error_OOM(t *testing.T) {
 	t.Parallel()
 
@@ -43,14 +49,18 @@ func TestConn_new(t *testing.T) {
 	}
 	defer m.close()
 
-	testOOM := func(size uint64) {
+	t.Run("MaxUint32", func(t *testing.T) {
 		defer func() { _ = recover() }()
-		m.new(size)
+		m.new(math.MaxUint32)
 		t.Error("want panic")
-	}
+	})
 
-	testOOM(math.MaxUint32)
-	testOOM(_MAX_ALLOCATION_SIZE)
+	t.Run("_MAX_ALLOCATION_SIZE", func(t *testing.T) {
+		defer func() { _ = recover() }()
+		m.new(_MAX_ALLOCATION_SIZE)
+		m.new(_MAX_ALLOCATION_SIZE)
+		t.Error("want panic")
+	})
 }
 
 func TestConn_newArena(t *testing.T) {
@@ -71,7 +81,7 @@ func TestConn_newArena(t *testing.T) {
 	if ptr == 0 {
 		t.Fatalf("got nullptr")
 	}
-	if got := m.mem.readString(ptr, math.MaxUint32); got != title {
+	if got := util.ReadString(m.mod, ptr, math.MaxUint32); got != title {
 		t.Errorf("got %q, want %q", got, title)
 	}
 
@@ -80,7 +90,7 @@ func TestConn_newArena(t *testing.T) {
 	if ptr == 0 {
 		t.Fatalf("got nullptr")
 	}
-	if got := m.mem.readString(ptr, math.MaxUint32); got != body {
+	if got := util.ReadString(m.mod, ptr, math.MaxUint32); got != body {
 		t.Errorf("got %q, want %q", got, body)
 	}
 	arena.free()
@@ -107,7 +117,7 @@ func TestConn_newBytes(t *testing.T) {
 	}
 
 	want := buf
-	if got := m.mem.view(ptr, uint64(len(want))); !bytes.Equal(got, want) {
+	if got := util.View(m.mod, ptr, uint64(len(want))); !bytes.Equal(got, want) {
 		t.Errorf("got %q, want %q", got, want)
 	}
 }
@@ -133,7 +143,7 @@ func TestConn_newString(t *testing.T) {
 	}
 
 	want := str + "\000"
-	if got := m.mem.view(ptr, uint64(len(want))); string(got) != want {
+	if got := util.View(m.mod, ptr, uint64(len(want))); string(got) != want {
 		t.Errorf("got %q, want %q", got, want)
 	}
 }
@@ -159,22 +169,22 @@ func TestConn_getString(t *testing.T) {
 	}
 
 	want := "sqlite3"
-	if got := m.mem.readString(ptr, math.MaxUint32); got != want {
+	if got := util.ReadString(m.mod, ptr, math.MaxUint32); got != want {
 		t.Errorf("got %q, want %q", got, want)
 	}
-	if got := m.mem.readString(ptr, 0); got != "" {
+	if got := util.ReadString(m.mod, ptr, 0); got != "" {
 		t.Errorf("got %q, want empty", got)
 	}
 
 	func() {
 		defer func() { _ = recover() }()
-		m.mem.readString(ptr, uint32(len(want)/2))
+		util.ReadString(m.mod, ptr, uint32(len(want)/2))
 		t.Error("want panic")
 	}()
 
 	func() {
 		defer func() { _ = recover() }()
-		m.mem.readString(0, math.MaxUint32)
+		util.ReadString(m.mod, 0, math.MaxUint32)
 		t.Error("want panic")
 	}()
 }

sqlite3/download.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-set -eo pipefail
+set -euo pipefail
 
 cd -P -- "$(dirname -- "$0")"
 
@@ -17,7 +17,7 @@ curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.41.2/ext/misc/regexp.c
 curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.41.2/ext/misc/series.c"
 cd ~-
 
-cd ../tests/mptest/testdata/
+cd ../internal/vfs/tests/mptest/testdata/
 curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.41.2/mptest/mptest.c"
 curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.41.2/mptest/config01.test"
 curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.41.2/mptest/config02.test"
@@ -26,6 +26,6 @@ curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.41.2/mptest/crash02.su
 curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.41.2/mptest/multiwrite01.test"
 cd ~-
 
-cd ../tests/speedtest1/testdata/
+cd ../internal/vfs/tests/speedtest1/testdata/
 curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.41.2/test/speedtest1.c"
 cd ~-

sqlite3/format.sh

@@ -1,4 +1,6 @@
 #!/usr/bin/env bash
+set -euo pipefail
+
 cd -P -- "$(dirname -- "$0")"
 
 shopt -s extglob

sqlite3/main.c

@@ -4,7 +4,6 @@
 #include "sqlite3.c"
 //
 #include "os.c"
-#include "qsort.c"
 //
 #include "ext/base64.c"
 #include "ext/decimal.c"
@@ -21,7 +20,7 @@ int sqlite3_os_init() {
   return sqlite3_vfs_register(os_vfs(), /*default=*/true);
 }
 
-__attribute__((constructor)) void premain() {
+__attribute__((constructor)) void init() {
   sqlite3_initialize();
   sqlite3_auto_extension((void (*)(void))sqlite3_base_init);
   sqlite3_auto_extension((void (*)(void))sqlite3_decimal_init);

sqlite3/os.c

@@ -17,16 +17,10 @@ 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;
+  int handle;
 };
 
-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");
+static_assert(offsetof(struct os_file, handle) == 4, "Unexpected offset");
 
 int os_close(sqlite3_file *);
 int os_read(sqlite3_file *, void *, int iAmt, sqlite3_int64 iOfst);
@@ -35,6 +29,8 @@ 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_sector_size(sqlite3_file *file);
+int os_device_characteristics(sqlite3_file *file);
 
 int os_lock(sqlite3_file *, int eLock);
 int os_unlock(sqlite3_file *, int eLock);
@@ -42,49 +38,11 @@ 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);
+  if (op == SQLITE_FCNTL_VFSNAME) {
+    *(char **)pArg = sqlite3_mprintf("%s", "os");
+    return SQLITE_OK;
   }
-  // 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;
+  return os_file_control(file, op, pArg);
 }
 
 static int os_open_w(sqlite3_vfs *vfs, sqlite3_filename zName,
@@ -110,12 +68,7 @@ static int os_open_w(sqlite3_vfs *vfs, sqlite3_filename zName,
     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);
-  }
+  file->pMethods = &os_io;
   return SQLITE_OK;
 }
 

sqlite3/qsort.c

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

sqlite3/sqlite_cfg.h

@@ -28,8 +28,11 @@
 #define SQLITE_OMIT_AUTOINIT
 #define SQLITE_USE_ALLOCA
 
+// Other Options
+// #define SQLITE_ALLOW_URI_AUTHORITY
+
 // Because WASM does not support shared memory,
-// SQLite disables it for WASM builds.
+// SQLite disables WAL for WASM builds.
 // We set the default locking mode to EXCLUSIVE instead.
 // https://www.sqlite.org/wal.html#noshm
 #undef SQLITE_OMIT_WAL
@@ -48,15 +51,9 @@
 #define SQLITE_ENABLE_RTREE 1
 #define SQLITE_ENABLE_GEOPOLY 1
 
-// Snapshot
-// #define SQLITE_ENABLE_SNAPSHOT 1
-
 // Session Extension
 // #define SQLITE_ENABLE_SESSION 1
 // #define SQLITE_ENABLE_PREUPDATE_HOOK 1
 
-// Resumable Bulk Update Extension
-// #define SQLITE_ENABLE_RBU 1
-
 // Implemented in Go.
 int localtime_s(struct tm *const pTm, time_t const *const pTime);

stmt.go

@@ -3,6 +3,8 @@ package sqlite3
 import (
 	"math"
 	"time"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
 )
 
 // Stmt is a prepared statement object.
@@ -10,8 +12,8 @@ import (
 // https://www.sqlite.org/c3ref/stmt.html
 type Stmt struct {
 	c      *Conn
-	handle uint32
 	err    error
+	handle uint32
 }
 
 // Close destroys the prepared statement object.
@@ -119,7 +121,7 @@ func (s *Stmt) BindName(param int) string {
 	if ptr == 0 {
 		return ""
 	}
-	return s.c.mem.readString(ptr, _MAX_STRING)
+	return util.ReadString(s.c.mod, ptr, _MAX_STRING)
 }
 
 // BindBool binds a bool to the prepared statement.
@@ -172,7 +174,7 @@ func (s *Stmt) BindText(param int, value string) error {
 	r := s.c.call(s.c.api.bindText,
 		uint64(s.handle), uint64(param),
 		uint64(ptr), uint64(len(value)),
-		s.c.api.destructor, _UTF8)
+		uint64(s.c.api.destructor), _UTF8)
 	return s.c.error(r[0])
 }
 
@@ -186,7 +188,7 @@ func (s *Stmt) BindBlob(param int, value []byte) error {
 	r := s.c.call(s.c.api.bindBlob,
 		uint64(s.handle), uint64(param),
 		uint64(ptr), uint64(len(value)),
-		s.c.api.destructor)
+		uint64(s.c.api.destructor))
 	return s.c.error(r[0])
 }
 
@@ -215,6 +217,9 @@ func (s *Stmt) BindNull(param int) error {
 //
 // https://www.sqlite.org/c3ref/bind_blob.html
 func (s *Stmt) BindTime(param int, value time.Time, format TimeFormat) error {
+	if format == TimeFormatDefault {
+		return s.bindRFC3339Nano(param, value)
+	}
 	switch v := format.Encode(value).(type) {
 	case string:
 		s.BindText(param, v)
@@ -223,11 +228,25 @@ func (s *Stmt) BindTime(param int, value time.Time, format TimeFormat) error {
 	case float64:
 		s.BindFloat(param, v)
 	default:
-		panic(assertErr())
+		panic(util.AssertErr())
 	}
 	return nil
 }
 
+func (s *Stmt) bindRFC3339Nano(param int, value time.Time) error {
+	const maxlen = uint64(len(time.RFC3339Nano))
+
+	ptr := s.c.new(maxlen)
+	buf := util.View(s.c.mod, ptr, maxlen)
+	buf = value.AppendFormat(buf[:0], time.RFC3339Nano)
+
+	r := s.c.call(s.c.api.bindText,
+		uint64(s.handle), uint64(param),
+		uint64(ptr), uint64(len(buf)),
+		uint64(s.c.api.destructor), _UTF8)
+	return s.c.error(r[0])
+}
+
 // ColumnCount returns the number of columns in a result set.
 //
 // https://www.sqlite.org/c3ref/column_count.html
@@ -247,9 +266,9 @@ func (s *Stmt) ColumnName(col int) string {
 
 	ptr := uint32(r[0])
 	if ptr == 0 {
-		panic(oomErr)
+		panic(util.OOMErr)
 	}
-	return s.c.mem.readString(ptr, _MAX_STRING)
+	return util.ReadString(s.c.mod, ptr, _MAX_STRING)
 }
 
 // ColumnType returns the initial [Datatype] of the result column.
@@ -320,7 +339,7 @@ func (s *Stmt) ColumnTime(col int, format TimeFormat) time.Time {
 	case NULL:
 		return time.Time{}
 	default:
-		panic(assertErr())
+		panic(util.AssertErr())
 	}
 	t, err := format.Decode(v)
 	if err != nil {
@@ -366,7 +385,7 @@ func (s *Stmt) ColumnRawText(col int) []byte {
 	r = s.c.call(s.c.api.columnBytes,
 		uint64(s.handle), uint64(col))
 
-	return s.c.mem.view(ptr, r[0])
+	return util.View(s.c.mod, ptr, r[0])
 }
 
 // ColumnRawBlob returns the value of the result column as a []byte.
@@ -389,7 +408,7 @@ func (s *Stmt) ColumnRawBlob(col int) []byte {
 	r = s.c.call(s.c.api.columnBytes,
 		uint64(s.handle), uint64(col))
 
-	return s.c.mem.view(ptr, r[0])
+	return util.View(s.c.mod, ptr, r[0])
 }
 
 // Return true if stmt is an empty SQL statement.

tests/mptest/testdata/build.sh

@@ -1,17 +0,0 @@
-#!/usr/bin/env bash
-set -eo pipefail
-
-cd -P -- "$(dirname -- "$0")"
-
-zig cc --target=wasm32-wasi -flto -g0 -O2 \
-  -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

tests/mptest/testdata/mptest.wasm

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:f81ce390812d944d1fa9b2cc607a3629febab0bc0e4473dad3170134509c1751
-size 1630826

tests/speedtest1/testdata/build.sh

@@ -1,12 +0,0 @@
-#!/usr/bin/env bash
-set -eo pipefail
-
-cd -P -- "$(dirname -- "$0")"
-
-zig cc --target=wasm32-wasi -flto -g0 -O2 \
-  -o speedtest1.wasm main.c \
-	-I../../../sqlite3/ \
-	-mmutable-globals \
-	-mbulk-memory -mreference-types \
-	-mnontrapping-fptoint -msign-ext \
-	-D_HAVE_SQLITE_CONFIG_H

tests/speedtest1/testdata/speedtest1.wasm

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:0e02a26b86832a4703cd2a86c98ff8041d9d889b865a61f324b512a15d2d361e
-size 1676129

time.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/ncruces/go-sqlite3/internal/util"
 	"github.com/ncruces/julianday"
 )
 
@@ -148,7 +149,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		case int64:
 			return julianday.Time(v, 0), nil
 		default:
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 
 	case TimeFormatUnix, TimeFormatUnixFrac:
@@ -167,7 +168,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		case int64:
 			return time.Unix(v, 0), nil
 		default:
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 
 	case TimeFormatUnixMilli:
@@ -184,7 +185,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		case int64:
 			return time.UnixMilli(int64(v)), nil
 		default:
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 
 	case TimeFormatUnixMicro:
@@ -201,14 +202,14 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		case int64:
 			return time.UnixMicro(int64(v)), nil
 		default:
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 
 	case TimeFormatUnixNano:
 		if s, ok := v.(string); ok {
 			i, err := strconv.ParseInt(s, 10, 64)
 			if err != nil {
-				return time.Time{}, timeErr
+				return time.Time{}, util.TimeErr
 			}
 			v = i
 		}
@@ -218,7 +219,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		case int64:
 			return time.Unix(0, int64(v)), nil
 		default:
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 
 	// Special formats
@@ -288,7 +289,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 			}
 			return TimeFormatUnixNano.Decode(v)
 		default:
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 
 	case
@@ -300,7 +301,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		TimeFormat7, TimeFormat7TZ:
 		s, ok := v.(string)
 		if !ok {
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 		return f.parseRelaxed(s)
 
@@ -310,7 +311,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 		TimeFormat10, TimeFormat10TZ:
 		s, ok := v.(string)
 		if !ok {
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 		t, err := f.parseRelaxed(s)
 		return t.AddDate(2000, 0, 0), err
@@ -318,7 +319,7 @@ func (f TimeFormat) Decode(v any) (time.Time, error) {
 	default:
 		s, ok := v.(string)
 		if !ok {
-			return time.Time{}, timeErr
+			return time.Time{}, util.TimeErr
 		}
 		if f == "" {
 			f = time.RFC3339Nano

vfs.go

@@ -1,418 +0,0 @@
-package sqlite3
-
-import (
-	"context"
-	"crypto/rand"
-	"errors"
-	"io"
-	"io/fs"
-	"os"
-	"path/filepath"
-	"runtime"
-	"time"
-
-	"github.com/ncruces/julianday"
-	"github.com/tetratelabs/wazero"
-	"github.com/tetratelabs/wazero/api"
-)
-
-func vfsInstantiate(ctx context.Context, r wazero.Runtime) {
-	env := vfsNewEnvModuleBuilder(r)
-	_, err := env.Instantiate(ctx)
-	if err != nil {
-		panic(err)
-	}
-}
-
-func vfsNewEnvModuleBuilder(r wazero.Runtime) wazero.HostModuleBuilder {
-	env := r.NewHostModuleBuilder("env")
-	vfsRegisterFuncT(env, "os_localtime", vfsLocaltime)
-	vfsRegisterFunc3(env, "os_randomness", vfsRandomness)
-	vfsRegisterFunc2(env, "os_sleep", vfsSleep)
-	vfsRegisterFunc2(env, "os_current_time", vfsCurrentTime)
-	vfsRegisterFunc2(env, "os_current_time_64", vfsCurrentTime64)
-	vfsRegisterFunc4(env, "os_full_pathname", vfsFullPathname)
-	vfsRegisterFunc3(env, "os_delete", vfsDelete)
-	vfsRegisterFunc4(env, "os_access", vfsAccess)
-	vfsRegisterFunc5(env, "os_open", vfsOpen)
-	vfsRegisterFunc1(env, "os_close", vfsClose)
-	vfsRegisterFuncRW(env, "os_read", vfsRead)
-	vfsRegisterFuncRW(env, "os_write", vfsWrite)
-	vfsRegisterFuncT(env, "os_truncate", vfsTruncate)
-	vfsRegisterFunc2(env, "os_sync", vfsSync)
-	vfsRegisterFunc2(env, "os_file_size", vfsFileSize)
-	vfsRegisterFunc2(env, "os_lock", vfsLock)
-	vfsRegisterFunc2(env, "os_unlock", vfsUnlock)
-	vfsRegisterFunc2(env, "os_check_reserved_lock", vfsCheckReservedLock)
-	vfsRegisterFunc3(env, "os_file_control", vfsFileControl)
-	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 vfsLocaltime(ctx context.Context, mod api.Module, pTm uint32, t uint64) uint32 {
-	tm := time.Unix(int64(t), 0)
-	var isdst int
-	if tm.IsDST() {
-		isdst = 1
-	}
-
-	// https://pubs.opengroup.org/onlinepubs/7908799/xsh/time.h.html
-	mem := memory{mod}
-	mem.writeUint32(pTm+0*ptrlen, uint32(tm.Second()))
-	mem.writeUint32(pTm+1*ptrlen, uint32(tm.Minute()))
-	mem.writeUint32(pTm+2*ptrlen, uint32(tm.Hour()))
-	mem.writeUint32(pTm+3*ptrlen, uint32(tm.Day()))
-	mem.writeUint32(pTm+4*ptrlen, uint32(tm.Month()-time.January))
-	mem.writeUint32(pTm+5*ptrlen, uint32(tm.Year()-1900))
-	mem.writeUint32(pTm+6*ptrlen, uint32(tm.Weekday()-time.Sunday))
-	mem.writeUint32(pTm+7*ptrlen, uint32(tm.YearDay()-1))
-	mem.writeUint32(pTm+8*ptrlen, uint32(isdst))
-	return _OK
-}
-
-func vfsRandomness(ctx context.Context, mod api.Module, pVfs, nByte, zByte uint32) uint32 {
-	mem := memory{mod}.view(zByte, uint64(nByte))
-	n, _ := rand.Reader.Read(mem)
-	return uint32(n)
-}
-
-func vfsSleep(ctx context.Context, mod api.Module, pVfs, nMicro uint32) uint32 {
-	time.Sleep(time.Duration(nMicro) * time.Microsecond)
-	return _OK
-}
-
-func vfsCurrentTime(ctx context.Context, mod api.Module, pVfs, prNow uint32) uint32 {
-	day := julianday.Float(time.Now())
-	memory{mod}.writeFloat64(prNow, day)
-	return _OK
-}
-
-func vfsCurrentTime64(ctx context.Context, mod api.Module, pVfs, piNow uint32) uint32 {
-	day, nsec := julianday.Date(time.Now())
-	msec := day*86_400_000 + nsec/1_000_000
-	memory{mod}.writeUint64(piNow, uint64(msec))
-	return _OK
-}
-
-func vfsFullPathname(ctx context.Context, mod api.Module, pVfs, zRelative, nFull, zFull uint32) uint32 {
-	rel := memory{mod}.readString(zRelative, _MAX_PATHNAME)
-	abs, err := filepath.Abs(rel)
-	if err != nil {
-		return uint32(CANTOPEN_FULLPATH)
-	}
-
-	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)
-
-	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 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 {
-			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 {
-	path := memory{mod}.readString(zPath, _MAX_PATHNAME)
-	err := vfsOS.Access(path, flags)
-
-	var res uint32
-	var rc xErrorCode
-	if flags == _ACCESS_EXISTS {
-		switch {
-		case err == nil:
-			res = 1
-		case errors.Is(err, fs.ErrNotExist):
-			res = 0
-		default:
-			rc = IOERR_ACCESS
-		}
-	} else {
-		switch {
-		case err == nil:
-			res = 1
-		case errors.Is(err, fs.ErrPermission):
-			res = 0
-		default:
-			rc = IOERR_ACCESS
-		}
-	}
-
-	memory{mod}.writeUint32(pResOut, res)
-	return uint32(rc)
-}
-
-func vfsOpen(ctx context.Context, mod api.Module, pVfs, zName, pFile uint32, flags OpenFlag, pOutFlags uint32) uint32 {
-	var oflags int
-	if flags&OPEN_EXCLUSIVE != 0 {
-		oflags |= os.O_EXCL
-	}
-	if flags&OPEN_CREATE != 0 {
-		oflags |= os.O_CREATE
-	}
-	if flags&OPEN_READONLY != 0 {
-		oflags |= os.O_RDONLY
-	}
-	if flags&OPEN_READWRITE != 0 {
-		oflags |= os.O_RDWR
-	}
-
-	var err error
-	var file *os.File
-	if zName == 0 {
-		file, err = os.CreateTemp("", "*.db")
-	} else {
-		name := memory{mod}.readString(zName, _MAX_PATHNAME)
-		file, err = vfsOS.OpenFile(name, oflags, 0600)
-	}
-	if err != nil {
-		return uint32(CANTOPEN)
-	}
-
-	if flags&OPEN_DELETEONCLOSE != 0 {
-		os.Remove(file.Name())
-	}
-
-	vfsFile.Open(ctx, mod, pFile, file)
-
-	if pOutFlags != 0 {
-		memory{mod}.writeUint32(pOutFlags, uint32(flags))
-	}
-	return _OK
-}
-
-func vfsClose(ctx context.Context, mod api.Module, pFile uint32) uint32 {
-	err := vfsFile.Close(ctx, mod, pFile)
-	if err != nil {
-		return uint32(IOERR_CLOSE)
-	}
-	return _OK
-}
-
-func vfsRead(ctx context.Context, mod api.Module, pFile, zBuf, iAmt uint32, iOfst uint64) uint32 {
-	buf := memory{mod}.view(zBuf, uint64(iAmt))
-
-	file := vfsFile.GetOS(ctx, mod, pFile)
-	n, err := file.ReadAt(buf, int64(iOfst))
-	if n == int(iAmt) {
-		return _OK
-	}
-	if n == 0 && err != io.EOF {
-		return uint32(IOERR_READ)
-	}
-	for i := range buf[n:] {
-		buf[n+i] = 0
-	}
-	return uint32(IOERR_SHORT_READ)
-}
-
-func vfsWrite(ctx context.Context, mod api.Module, pFile, zBuf, iAmt uint32, iOfst uint64) uint32 {
-	buf := memory{mod}.view(zBuf, uint64(iAmt))
-
-	file := vfsFile.GetOS(ctx, mod, pFile)
-	_, err := file.WriteAt(buf, int64(iOfst))
-	if err != nil {
-		return uint32(IOERR_WRITE)
-	}
-	return _OK
-}
-
-func vfsTruncate(ctx context.Context, mod api.Module, pFile uint32, nByte uint64) uint32 {
-	file := vfsFile.GetOS(ctx, mod, pFile)
-	err := file.Truncate(int64(nByte))
-	if err != nil {
-		return uint32(IOERR_TRUNCATE)
-	}
-	return _OK
-}
-
-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)
-	}
-	return _OK
-}
-
-func vfsFileSize(ctx context.Context, mod api.Module, pFile, pSize uint32) uint32 {
-	file := vfsFile.GetOS(ctx, mod, pFile)
-	off, err := file.Seek(0, io.SeekEnd)
-	if err != nil {
-		return uint32(IOERR_SEEK)
-	}
-
-	memory{mod}.writeUint64(pSize, uint64(off))
-	return _OK
-}
-
-func vfsFileControl(ctx context.Context, 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 != 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
-}
-
-func vfsRegisterFunc1(mod wazero.HostModuleBuilder, name string, fn func(ctx context.Context, mod api.Module, _ uint32) uint32) {
-	mod.NewFunctionBuilder().
-		WithGoModuleFunction(api.GoModuleFunc(
-			func(ctx context.Context, mod api.Module, stack []uint64) {
-				stack[0] = uint64(fn(ctx, mod, uint32(stack[0])))
-			}),
-			[]api.ValueType{api.ValueTypeI32}, []api.ValueType{api.ValueTypeI32}).
-		Export(name)
-}
-
-func vfsRegisterFunc2[T0, T1 ~uint32](mod wazero.HostModuleBuilder, name string, fn func(ctx context.Context, mod api.Module, _ T0, _ T1) uint32) {
-	mod.NewFunctionBuilder().
-		WithGoModuleFunction(api.GoModuleFunc(
-			func(ctx context.Context, mod api.Module, stack []uint64) {
-				stack[0] = uint64(fn(ctx, mod, T0(stack[0]), T1(stack[1])))
-			}),
-			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI32}, []api.ValueType{api.ValueTypeI32}).
-		Export(name)
-}
-
-func vfsRegisterFunc3[T0, T1, T2 ~uint32](mod wazero.HostModuleBuilder, name string, fn func(ctx context.Context, mod api.Module, _ T0, _ T1, _ T2) uint32) {
-	mod.NewFunctionBuilder().
-		WithGoModuleFunction(api.GoModuleFunc(
-			func(ctx context.Context, mod api.Module, stack []uint64) {
-				stack[0] = uint64(fn(ctx, mod, T0(stack[0]), T1(stack[1]), T2(stack[2])))
-			}),
-			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32}, []api.ValueType{api.ValueTypeI32}).
-		Export(name)
-}
-
-func vfsRegisterFunc4[T0, T1, T2, T3 ~uint32](mod wazero.HostModuleBuilder, name string, fn func(ctx context.Context, mod api.Module, _ T0, _ T1, _ T2, _ T3) uint32) {
-	mod.NewFunctionBuilder().
-		WithGoModuleFunction(api.GoModuleFunc(
-			func(ctx context.Context, mod api.Module, stack []uint64) {
-				stack[0] = uint64(fn(ctx, mod, T0(stack[0]), T1(stack[1]), T2(stack[2]), T3(stack[3])))
-			}),
-			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32}, []api.ValueType{api.ValueTypeI32}).
-		Export(name)
-}
-
-func vfsRegisterFunc5[T0, T1, T2, T3, T4 ~uint32](mod wazero.HostModuleBuilder, name string, fn func(ctx context.Context, mod api.Module, _ T0, _ T1, _ T2, _ T3, _ T4) uint32) {
-	mod.NewFunctionBuilder().
-		WithGoModuleFunction(api.GoModuleFunc(
-			func(ctx context.Context, mod api.Module, stack []uint64) {
-				stack[0] = uint64(fn(ctx, mod, T0(stack[0]), T1(stack[1]), T2(stack[2]), T3(stack[3]), T4(stack[4])))
-			}),
-			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32}, []api.ValueType{api.ValueTypeI32}).
-		Export(name)
-}
-
-func vfsRegisterFuncRW(mod wazero.HostModuleBuilder, name string, fn func(ctx context.Context, mod api.Module, _, _, _ uint32, _ uint64) uint32) {
-	mod.NewFunctionBuilder().
-		WithGoModuleFunction(api.GoModuleFunc(
-			func(ctx context.Context, mod api.Module, stack []uint64) {
-				stack[0] = uint64(fn(ctx, mod, uint32(stack[0]), uint32(stack[1]), uint32(stack[2]), stack[3]))
-			}),
-			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI32, api.ValueTypeI64}, []api.ValueType{api.ValueTypeI32}).
-		Export(name)
-}
-
-func vfsRegisterFuncT(mod wazero.HostModuleBuilder, name string, fn func(ctx context.Context, mod api.Module, _ uint32, _ uint64) uint32) {
-	mod.NewFunctionBuilder().
-		WithGoModuleFunction(api.GoModuleFunc(
-			func(ctx context.Context, mod api.Module, stack []uint64) {
-				stack[0] = uint64(fn(ctx, mod, uint32(stack[0]), stack[1]))
-			}),
-			[]api.ValueType{api.ValueTypeI32, api.ValueTypeI64}, []api.ValueType{api.ValueTypeI32}).
-		Export(name)
-}

vfs_file.go

@@ -1,69 +0,0 @@
-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_lock.go

@@ -1,207 +0,0 @@
-package sqlite3
-
-import (
-	"context"
-	"os"
-	"time"
-
-	"github.com/tetratelabs/wazero/api"
-)
-
-const (
-	// No locks are held on the database.
-	// The database may be neither read nor written.
-	// Any internally cached data is considered suspect and subject to
-	// verification against the database file before being used.
-	// Other processes can read or write the database as their own locking
-	// states permit.
-	// This is the default state.
-	_NO_LOCK = 0
-
-	// The database may be read but not written.
-	// Any number of processes can hold SHARED locks at the same time,
-	// hence there can be many simultaneous readers.
-	// But no other thread or process is allowed to write to the database file
-	// while one or more SHARED locks are active.
-	_SHARED_LOCK = 1
-
-	// A RESERVED lock means that the process is planning on writing to the
-	// database file at some point in the future but that it is currently just
-	// reading from the file.
-	// Only a single RESERVED lock may be active at one time,
-	// though multiple SHARED locks can coexist with a single RESERVED lock.
-	// RESERVED differs from PENDING in that new SHARED locks can be acquired
-	// while there is a RESERVED lock.
-	_RESERVED_LOCK = 2
-
-	// A PENDING lock means that the process holding the lock wants to write to
-	// the database as soon as possible and is just waiting on all current
-	// SHARED locks to clear so that it can get an EXCLUSIVE lock.
-	// No new SHARED locks are permitted against the database if a PENDING lock
-	// is active, though existing SHARED locks are allowed to continue.
-	_PENDING_LOCK = 3
-
-	// An EXCLUSIVE lock is needed in order to write to the database file.
-	// Only one EXCLUSIVE lock is allowed on the file and no other locks of any
-	// kind are allowed to coexist with an EXCLUSIVE lock.
-	// In order to maximize concurrency, SQLite works to minimize the amount of
-	// time that EXCLUSIVE locks are held.
-	_EXCLUSIVE_LOCK = 4
-
-	_PENDING_BYTE  = 0x40000000
-	_RESERVED_BYTE = (_PENDING_BYTE + 1)
-	_SHARED_FIRST  = (_PENDING_BYTE + 2)
-	_SHARED_SIZE   = 510
-)
-
-type vfsLockState uint32
-
-func vfsLock(ctx context.Context, mod api.Module, pFile uint32, eLock vfsLockState) uint32 {
-	// Argument check. SQLite never explicitly requests a pending lock.
-	if eLock != _SHARED_LOCK && eLock != _RESERVED_LOCK && eLock != _EXCLUSIVE_LOCK {
-		panic(assertErr())
-	}
-
-	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:
-		// Connection state check.
-		panic(assertErr())
-	case cLock == _NO_LOCK && eLock > _SHARED_LOCK:
-		// We never move from unlocked to anything higher than a shared lock.
-		panic(assertErr())
-	case cLock != _SHARED_LOCK && eLock == _RESERVED_LOCK:
-		// A shared lock is always held when a reserved lock is requested.
-		panic(assertErr())
-	}
-
-	// If we already have an equal or more restrictive lock, do nothing.
-	if cLock >= eLock {
-		return _OK
-	}
-
-	switch eLock {
-	case _SHARED_LOCK:
-		// Must be unlocked to get SHARED.
-		if cLock != _NO_LOCK {
-			panic(assertErr())
-		}
-		if rc := vfsOS.GetSharedLock(file, timeout); rc != _OK {
-			return uint32(rc)
-		}
-		vfsFile.SetLock(ctx, mod, pFile, _SHARED_LOCK)
-		return _OK
-
-	case _RESERVED_LOCK:
-		// Must be SHARED to get RESERVED.
-		if cLock != _SHARED_LOCK {
-			panic(assertErr())
-		}
-		if rc := vfsOS.GetReservedLock(file, timeout); rc != _OK {
-			return uint32(rc)
-		}
-		vfsFile.SetLock(ctx, mod, pFile, _RESERVED_LOCK)
-		return _OK
-
-	case _EXCLUSIVE_LOCK:
-		// Must be SHARED, RESERVED or PENDING to get EXCLUSIVE.
-		if cLock <= _NO_LOCK || cLock >= _EXCLUSIVE_LOCK {
-			panic(assertErr())
-		}
-		// A PENDING lock is needed before acquiring an EXCLUSIVE lock.
-		if cLock < _PENDING_LOCK {
-			if rc := vfsOS.GetPendingLock(file); rc != _OK {
-				return uint32(rc)
-			}
-			vfsFile.SetLock(ctx, mod, pFile, _PENDING_LOCK)
-		}
-		if rc := vfsOS.GetExclusiveLock(file, timeout); rc != _OK {
-			return uint32(rc)
-		}
-		vfsFile.SetLock(ctx, mod, pFile, _EXCLUSIVE_LOCK)
-		return _OK
-
-	default:
-		panic(assertErr())
-	}
-}
-
-func vfsUnlock(ctx context.Context, mod api.Module, pFile uint32, eLock vfsLockState) uint32 {
-	// Argument check.
-	if eLock != _NO_LOCK && eLock != _SHARED_LOCK {
-		panic(assertErr())
-	}
-
-	file := vfsFile.GetOS(ctx, mod, pFile)
-	cLock := vfsFile.GetLock(ctx, mod, pFile)
-
-	// Connection state check.
-	if cLock < _NO_LOCK || cLock > _EXCLUSIVE_LOCK {
-		panic(assertErr())
-	}
-
-	// If we don't have a more restrictive lock, do nothing.
-	if cLock <= eLock {
-		return _OK
-	}
-
-	switch eLock {
-	case _SHARED_LOCK:
-		if rc := vfsOS.DowngradeLock(file, cLock); rc != _OK {
-			return uint32(rc)
-		}
-		vfsFile.SetLock(ctx, mod, pFile, _SHARED_LOCK)
-		return _OK
-
-	case _NO_LOCK:
-		rc := vfsOS.ReleaseLock(file, cLock)
-		vfsFile.SetLock(ctx, mod, pFile, _NO_LOCK)
-		return uint32(rc)
-
-	default:
-		panic(assertErr())
-	}
-}
-
-func vfsCheckReservedLock(ctx context.Context, mod api.Module, pFile, pResOut uint32) uint32 {
-	file := vfsFile.GetOS(ctx, mod, pFile)
-	cLock := vfsFile.GetLock(ctx, mod, pFile)
-
-	// Connection state check.
-	if cLock < _NO_LOCK || cLock > _EXCLUSIVE_LOCK {
-		panic(assertErr())
-	}
-
-	var locked bool
-	var rc xErrorCode
-	if cLock >= _RESERVED_LOCK {
-		locked = true
-	} else {
-		locked, rc = vfsOS.CheckReservedLock(file)
-	}
-
-	var res uint32
-	if locked {
-		res = 1
-	}
-	memory{mod}.writeUint32(pResOut, res)
-	return uint32(rc)
-}
-
-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)
-}

vfs_os_bsd.go

@@ -1,56 +0,0 @@
-//go:build freebsd || openbsd || netbsd || dragonfly || (darwin && sqlite3_bsd)
-
-package sqlite3
-
-import (
-	"os"
-	"time"
-
-	"golang.org/x/sys/unix"
-)
-
-func (vfsOSMethods) unlock(file *os.File, start, len int64) xErrorCode {
-	if start == 0 && len == 0 {
-		err := unix.Flock(int(file.Fd()), unix.LOCK_UN)
-		if err != nil {
-			return IOERR_UNLOCK
-		}
-	}
-	return _OK
-}
-
-func (vfsOSMethods) lock(file *os.File, how int, timeout time.Duration, def xErrorCode) xErrorCode {
-	var err error
-	for {
-		err = unix.Flock(int(file.Fd()), how)
-		if errno, _ := err.(unix.Errno); errno != unix.EAGAIN {
-			break
-		}
-		if timeout < time.Millisecond {
-			break
-		}
-		timeout -= time.Millisecond
-		time.Sleep(time.Millisecond)
-	}
-	return vfsOS.lockErrorCode(err, def)
-}
-
-func (vfsOSMethods) readLock(file *os.File, start, len int64, timeout time.Duration) xErrorCode {
-	return vfsOS.lock(file, unix.LOCK_SH|unix.LOCK_NB, timeout, IOERR_RDLOCK)
-}
-
-func (vfsOSMethods) writeLock(file *os.File, start, len int64, timeout time.Duration) xErrorCode {
-	return vfsOS.lock(file, unix.LOCK_EX|unix.LOCK_NB, 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 unix.FcntlFlock(file.Fd(), unix.F_GETLK, &lock) != nil {
-		return false, IOERR_CHECKRESERVEDLOCK
-	}
-	return lock.Type != unix.F_UNLCK, _OK
-}

vfs_os_unix.go

@@ -1,87 +0,0 @@
-//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) GetSharedLock(file *os.File, timeout time.Duration) xErrorCode {
-	// Test the PENDING lock before acquiring a new SHARED lock.
-	if pending, _ := vfsOS.checkLock(file, _PENDING_BYTE, 1); pending {
-		return xErrorCode(BUSY)
-	}
-	// Acquire the SHARED lock.
-	return vfsOS.readLock(file, _SHARED_FIRST, _SHARED_SIZE, timeout)
-}
-
-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) 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
-}