mirror of
https://github.com/ncruces/go-sqlite3.git
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73 lines
2.0 KiB
Go
73 lines
2.0 KiB
Go
// Package serdes provides functions to (de)serialize databases.
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package serdes
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import (
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"github.com/ncruces/go-sqlite3"
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"github.com/ncruces/go-sqlite3/util/vfsutil"
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"github.com/ncruces/go-sqlite3/vfs"
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)
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const vfsName = "github.com/ncruces/go-sqlite3/ext/serdes.sliceVFS"
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func init() {
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vfs.Register(vfsName, sliceVFS{})
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}
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var fileToOpen = make(chan *[]byte, 1)
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// Serialize backs up a database into a byte slice.
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//
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// https://sqlite.org/c3ref/serialize.html
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func Serialize(db *sqlite3.Conn, schema string) ([]byte, error) {
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var file []byte
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fileToOpen <- &file
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err := db.Backup(schema, "file:serdes.db?nolock=1&vfs="+vfsName)
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return file, err
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}
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// Deserialize restores a database from a byte slice,
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// DESTROYING any contents previously stored in schema.
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//
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// To non-destructively open a database from a byte slice,
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// consider alternatives like the ["reader"] or ["memdb"] VFSes.
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//
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// This differs from the similarly named SQLite API
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// in that it DOES NOT disconnect from schema
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// to reopen as an in-memory database.
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//
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// https://sqlite.org/c3ref/deserialize.html
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//
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// ["memdb"]: https://pkg.go.dev/github.com/ncruces/go-sqlite3/vfs/memdb
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// ["reader"]: https://pkg.go.dev/github.com/ncruces/go-sqlite3/vfs/readervfs
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func Deserialize(db *sqlite3.Conn, schema string, data []byte) error {
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fileToOpen <- &data
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return db.Restore(schema, "file:serdes.db?immutable=1&vfs="+vfsName)
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}
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type sliceVFS struct{}
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func (sliceVFS) Open(name string, flags vfs.OpenFlag) (vfs.File, vfs.OpenFlag, error) {
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if flags&vfs.OPEN_MAIN_DB == 0 || name != "serdes.db" {
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return nil, flags, sqlite3.CANTOPEN
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}
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select {
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case file := <-fileToOpen:
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return (*vfsutil.SliceFile)(file), flags | vfs.OPEN_MEMORY, nil
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default:
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return nil, flags, sqlite3.MISUSE
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}
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}
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func (sliceVFS) Delete(name string, dirSync bool) error {
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// notest // no journals to delete
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return sqlite3.IOERR_DELETE
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}
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func (sliceVFS) Access(name string, flag vfs.AccessFlag) (bool, error) {
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return name == "serdes.db", nil
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}
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func (sliceVFS) FullPathname(name string) (string, error) {
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return name, nil
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}
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