Prepare statements.

build_deps.sh

@@ -34,7 +34,8 @@ zig cc --target=wasm32-wasi -flto -g0 -O2 \
 	-DSQLITE_OMIT_UTF16 \
 	-Wl,--export=sqlite3_open_v2 \
 	-Wl,--export=sqlite3_close \
-	-Wl,--export=sqlite3_prepare_v2 \
+	-Wl,--export=sqlite3_prepare_v3 \
+	-Wl,--export=sqlite3_finalize \
 	-Wl,--export=sqlite3_exec \
 	-Wl,--export=sqlite3_step \
 	-Wl,--export=sqlite3_column_text \

cmd/main.go

@@ -23,6 +23,16 @@ func main() {
 		log.Fatal(err)
 	}
 
+	stmt, _, err := db.Prepare(`SELECT id, name FROM users`, 0)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	err = stmt.Close()
+	if err != nil {
+		log.Fatal(err)
+	}
+
 	err = db.Close()
 	if err != nil {
 		log.Fatal(err)

conn.go

@@ -56,7 +56,8 @@ func Open(name string, flags uint64, vfs string) (conn *Conn, err error) {
 			errext:      module.ExportedFunction("sqlite3_extended_errcode"),
 			open:        module.ExportedFunction("sqlite3_open_v2"),
 			close:       module.ExportedFunction("sqlite3_close"),
-			prepare:     module.ExportedFunction("sqlite3_prepare_v2"),
+			prepare:     module.ExportedFunction("sqlite3_prepare_v3"),
+			finalize:    module.ExportedFunction("sqlite3_finalize"),
 			exec:        module.ExportedFunction("sqlite3_exec"),
 			step:        module.ExportedFunction("sqlite3_step"),
 			columnText:  module.ExportedFunction("sqlite3_column_text"),
@@ -72,7 +73,7 @@ func Open(name string, flags uint64, vfs string) (conn *Conn, err error) {
 	}()
 
 	namePtr := c.newString(name)
-	handlePtr := c.newBytes(4)
+	connPtr := c.newBytes(ptrSize)
 
 	if flags == 0 {
 		flags = OPEN_READWRITE | OPEN_CREATE
@@ -83,13 +84,13 @@ func Open(name string, flags uint64, vfs string) (conn *Conn, err error) {
 		vfsPtr = c.newString(vfs)
 	}
 
-	r, err := c.api.open.Call(ctx, uint64(namePtr), uint64(handlePtr), flags, uint64(vfsPtr))
+	r, err := c.api.open.Call(ctx, uint64(namePtr), uint64(connPtr), flags, uint64(vfsPtr))
 	if err != nil {
 		return nil, err
 	}
 
-	c.handle, _ = c.memory.ReadUint32Le(handlePtr)
-	c.free(handlePtr)
+	c.handle, _ = c.memory.ReadUint32Le(connPtr)
+	c.free(connPtr)
 	c.free(namePtr)
 	c.free(vfsPtr)
 
@@ -127,6 +128,36 @@ func (c *Conn) Exec(sql string) error {
 	return nil
 }
 
+func (c *Conn) Prepare(sql string, flags uint64, args ...any) (stmt *Stmt, tail string, err error) {
+	sqlPtr := c.newString(sql)
+	stmtPtr := c.newBytes(ptrSize)
+	tailPtr := c.newBytes(ptrSize)
+
+	r, err := c.api.prepare.Call(context.TODO(), uint64(c.handle),
+		uint64(sqlPtr), uint64(len(sql)+1), flags,
+		uint64(stmtPtr), uint64(tailPtr))
+	if err != nil {
+		return nil, "", err
+	}
+
+	stmt = &Stmt{c: c}
+	stmt.handle, _ = c.memory.ReadUint32Le(stmtPtr)
+	i, _ := c.memory.ReadUint32Le(tailPtr)
+	tail = sql[i-sqlPtr:]
+
+	c.free(tailPtr)
+	c.free(stmtPtr)
+	c.free(sqlPtr)
+
+	if r[0] != OK {
+		return nil, "", c.error(r[0])
+	}
+	if stmt.handle == 0 {
+		return nil, "", nil
+	}
+	return
+}
+
 func (c *Conn) error(rc uint64) *Error {
 	serr := Error{Code: int(rc)}
 
@@ -209,6 +240,8 @@ func (c *Conn) getString(ptr, maxlen uint32) string {
 	}
 }
 
+const ptrSize = 4
+
 type sqliteAPI struct {
 	malloc      api.Function
 	free        api.Function
@@ -219,6 +252,7 @@ type sqliteAPI struct {
 	open        api.Function
 	close       api.Function
 	prepare     api.Function
+	finalize    api.Function
 	exec        api.Function
 	step        api.Function
 	columnInt   api.Function

go.mod

@@ -2,4 +2,4 @@ module github.com/ncruces/go-sqlite3
 
 go 1.19
 
-require github.com/tetratelabs/wazero v1.0.0-pre.7
+require github.com/tetratelabs/wazero v1.0.0-pre.7.0.20230114234926-2ce8988ab763

go.sum

@@ -1,2 +1,2 @@
-github.com/tetratelabs/wazero v1.0.0-pre.7 h1:WI5N14XxoXw+ZWhcjSazJ6rEowhJbH/x8hglxC5gN7k=
-github.com/tetratelabs/wazero v1.0.0-pre.7/go.mod h1:u8wrFmpdrykiFK0DFPiFm5a4+0RzsdmXYVtijBKqUVo=
+github.com/tetratelabs/wazero v1.0.0-pre.7.0.20230114234926-2ce8988ab763 h1:cuXa6OWMd3L3+nNrX9SfT6GxS6ykUAvx8/eegN6KeNo=
+github.com/tetratelabs/wazero v1.0.0-pre.7.0.20230114234926-2ce8988ab763/go.mod h1:u8wrFmpdrykiFK0DFPiFm5a4+0RzsdmXYVtijBKqUVo=

stmt.go

@@ -0,0 +1,21 @@
+package sqlite3
+
+import "context"
+
+type Stmt struct {
+	c      *Conn
+	handle uint32
+}
+
+func (s *Stmt) Close() error {
+	r, err := s.c.api.finalize.Call(context.TODO(), uint64(s.handle))
+	if err != nil {
+		return err
+	}
+
+	s.handle = 0
+	if r[0] != OK {
+		return s.c.error(r[0])
+	}
+	return nil
+}