Refactor.

build_deps.sh

@@ -4,16 +4,21 @@ set -eo pipefail
 cd -P -- "$(dirname -- "$0")"
 
 # download SQLite
-url="https://www.sqlite.org/2022/sqlite-amalgamation-3400100.zip"
-
-curl "$url" > sqlite3/sqlite.zip
-unzip -d sqlite3/ sqlite3/sqlite.zip
-mv sqlite3/sqlite-amalgamation-*/sqlite3* sqlite3/
-rm -rf sqlite3/sqlite-amalgamation-*
-rm sqlite3/sqlite.zip
+if [ ! -f "sqlite3/sqlite3.c" ]; then
+	url="https://www.sqlite.org/2022/sqlite-amalgamation-3400100.zip"
+	curl "$url" > sqlite3/sqlite.zip
+	unzip -d sqlite3/ sqlite3/sqlite.zip
+	mv sqlite3/sqlite-amalgamation-*/sqlite3* sqlite3/
+	rm -rf sqlite3/sqlite-amalgamation-*
+	rm sqlite3/sqlite.zip
+fi
 
 # build SQLite
-zig cc --target=wasm32-wasi -flto -g0 -O2 -o embed/sqlite3.wasm sqlite3/*.c \
+zig cc --target=wasm32-wasi -flto -g0 -O2 \
+  -o embed/sqlite3.wasm sqlite3/*.c \
+	-mmutable-globals \
+	-mbulk-memory -mreference-types \
+	-mnontrapping-fptoint -msign-ext \
 	-DSQLITE_OS_OTHER=1 -DSQLITE_BYTEORDER=1234 \
 	-DHAVE_ISNAN -DHAVE_MALLOC_USABLE_SIZE \
 	-DSQLITE_DQS=0 \
@@ -26,6 +31,7 @@ zig cc --target=wasm32-wasi -flto -g0 -O2 -o embed/sqlite3.wasm sqlite3/*.c \
 	-DSQLITE_OMIT_PROGRESS_CALLBACK \
 	-DSQLITE_OMIT_SHARED_CACHE \
 	-DSQLITE_OMIT_AUTOINIT \
+	-DSQLITE_OMIT_UTF16 \
 	-Wl,--export=sqlite3_open_v2 \
 	-Wl,--export=sqlite3_close \
 	-Wl,--export=sqlite3_prepare_v2 \

conn.go

@@ -89,7 +89,7 @@ func Open(name string, flags uint64, vfs string) (*Conn, error) {
 	namePtr := c.newString(name)
 	defer c.free(namePtr)
 
-	handlePtr := c.newPtr()
+	handlePtr := c.newBytes(4)
 	defer c.free(handlePtr)
 
 	var vfsPtr uint32
@@ -119,7 +119,7 @@ func (c *Conn) Errmsg() error {
 	if err != nil {
 		return err
 	}
-	return errors.New(c.getString(r[0]))
+	return errors.New(c.getString(uint32(r[0]), 64))
 }
 
 func (c *Conn) Close() error {
@@ -141,37 +141,43 @@ func (c *Conn) free(ptr uint32) {
 	}
 }
 
-func (c *Conn) newPtr() uint32 {
-	r, err := c.api.malloc.Call(context.TODO(), 4)
+func (c *Conn) newBytes(len uint32) uint32 {
+	r, err := c.api.malloc.Call(context.TODO(), uint64(len))
 	if err != nil {
 		panic(err)
 	}
+	if r[0] == 0 {
+		panic("sqlite3: out of memory")
+	}
 	return uint32(r[0])
 }
 
 func (c *Conn) newString(str string) uint32 {
-	r, err := c.api.malloc.Call(context.TODO(), uint64(len(str)+1))
-	if err != nil {
-		panic(err)
+	ptr := c.newBytes(uint32(len(str) + 1))
+
+	buf, ok := c.memory.Read(ptr, uint32(len(str)+1))
+	if !ok {
+		c.api.free.Call(context.TODO(), uint64(ptr))
+		panic("sqlite3: failed to init string")
 	}
 
-	ptr := uint32(r[0])
-	if ok := c.memory.Write(ptr, []byte(str)); !ok {
-		panic("failed init string")
-	}
-	if ok := c.memory.WriteByte(ptr+uint32(len(str)), 0); !ok {
-		panic("failed init string")
-	}
+	buf[len(str)] = 0
+	copy(buf, str)
 	return ptr
 }
 
-func (c *Conn) getString(ptr uint64) string {
-	buf, ok := c.memory.Read(uint32(ptr), 64)
+func (c *Conn) getString(ptr, maxlen uint32) string {
+	buf, ok := c.memory.Read(ptr, maxlen)
 	if !ok {
-		panic("failed read string")
+		if size := c.memory.Size(); ptr < size {
+			buf, ok = c.memory.Read(ptr, size-ptr)
+		}
+		if !ok {
+			panic("sqlite3: invalid pointer")
+		}
 	}
 	if i := bytes.IndexByte(buf, 0); i < 0 {
-		panic("failed read string")
+		panic("sqlite3: missing NUL terminator")
 	} else {
 		return string(buf[:i])
 	}

sqlite3/main.c

@@ -1,6 +1,6 @@
 #include "sqlite3.h"
 
-int main(int argc, char *argv[]) {
+int main() {
 	int rc = sqlite3_initialize();
 	if (rc != SQLITE_OK) return -1;
 }