Provide SQLite with its own memory for deserialize

rqlite/rqlite#739

Author: otoolep

sqlite3.go

@@ -931,6 +931,10 @@ func (c *SQLiteConn) Serialize(schema string) []byte {
 // byte slice. If deserelization fails, error will contain the return code
 // of the underlying SQLite API call.
 //
+// Because the byte slice is in Go-controlled memory, this function
+// makes a copy of the data in C-controlled memory, before passing the
+// data to the SQLite library.
+//
 // See https://www.sqlite.org/c3ref/deserialize.html
 func (c *SQLiteConn) Deserialize(b []byte, schema string) error {
 	if schema == "" {
@@ -941,8 +945,9 @@ func (c *SQLiteConn) Deserialize(b []byte, schema string) error {
 	defer C.free(unsafe.Pointer(zSchema))
 
 	rc := C.sqlite3_deserialize(c.db, zSchema,
-		(*C.uint8_t)(unsafe.Pointer(&b[0])),
-		C.sqlite3_int64(len(b)), C.sqlite3_int64(len(b)), 0)
+		(*C.uint8_t)(C.CBytes(b)),
+		C.sqlite3_int64(len(b)), C.sqlite3_int64(len(b)),
+		C.SQLITE_DESERIALIZE_FREEONCLOSE|C.SQLITE_DESERIALIZE_RESIZEABLE)
 	if rc != 0 {
 		return fmt.Errorf("deserialize failed with return %v", rc)
 	}