go-sqlite3-hak5/sqlite3_opt_serialize.go

83 lines
1.9 KiB
Go

// +build !libsqlite3 sqlite_serialize
package sqlite3
/*
#ifndef USE_LIBSQLITE3
#include <sqlite3-binding.h>
#else
#include <sqlite3.h>
#endif
#include <stdlib.h>
#include <stdint.h>
*/
import "C"
import (
"fmt"
"math"
"reflect"
"unsafe"
)
// Serialize returns a byte slice that is a serialization of the database.
//
// See https://www.sqlite.org/c3ref/serialize.html
func (c *SQLiteConn) Serialize(schema string) ([]byte, error) {
if schema == "" {
schema = "main"
}
var zSchema *C.char
zSchema = C.CString(schema)
defer C.free(unsafe.Pointer(zSchema))
var sz C.sqlite3_int64
ptr := C.sqlite3_serialize(c.db, zSchema, &sz, 0)
if ptr == nil {
return nil, fmt.Errorf("serialize failed")
}
defer C.sqlite3_free(unsafe.Pointer(ptr))
if sz > C.sqlite3_int64(math.MaxInt) {
return nil, fmt.Errorf("serialized database is too large (%d bytes)", sz)
}
cBuf := *(*[]byte)(unsafe.Pointer(&reflect.SliceHeader{
Data: uintptr(unsafe.Pointer(ptr)),
Len: int(sz),
Cap: int(sz),
}))
res := make([]byte, int(sz))
copy(res, cBuf)
return res, nil
}
// Deserialize causes the connection to disconnect from the current database and
// then re-open as an in-memory database based on the contents of the byte slice.
//
// See https://www.sqlite.org/c3ref/deserialize.html
func (c *SQLiteConn) Deserialize(b []byte, schema string) error {
if schema == "" {
schema = "main"
}
var zSchema *C.char
zSchema = C.CString(schema)
defer C.free(unsafe.Pointer(zSchema))
tmpBuf := (*C.uchar)(C.sqlite3_malloc64(C.sqlite3_uint64(len(b))))
cBuf := *(*[]byte)(unsafe.Pointer(&reflect.SliceHeader{
Data: uintptr(unsafe.Pointer(tmpBuf)),
Len: len(b),
Cap: len(b),
}))
copy(cBuf, b)
rc := C.sqlite3_deserialize(c.db, zSchema, tmpBuf, C.sqlite3_int64(len(b)),
C.sqlite3_int64(len(b)), C.SQLITE_DESERIALIZE_FREEONCLOSE)
if rc != C.SQLITE_OK {
return fmt.Errorf("deserialize failed with return %v", rc)
}
return nil
}