github.com/CanonicalLtd/go-sqlite3@v1.6.0/backup.go (about) 1 // Copyright (C) 2014 Yasuhiro Matsumoto <mattn.jp@gmail.com>. 2 // 3 // Use of this source code is governed by an MIT-style 4 // license that can be found in the LICENSE file. 5 6 package sqlite3 7 8 /* 9 #ifndef USE_LIBSQLITE3 10 #include <sqlite3-binding.h> 11 #else 12 #include <sqlite3.h> 13 #endif 14 #include <stdlib.h> 15 */ 16 import "C" 17 import ( 18 "runtime" 19 "unsafe" 20 ) 21 22 // SQLiteBackup implement interface of Backup. 23 type SQLiteBackup struct { 24 b *C.sqlite3_backup 25 } 26 27 // Backup make backup from src to dest. 28 func (c *SQLiteConn) Backup(dest string, conn *SQLiteConn, src string) (*SQLiteBackup, error) { 29 destptr := C.CString(dest) 30 defer C.free(unsafe.Pointer(destptr)) 31 srcptr := C.CString(src) 32 defer C.free(unsafe.Pointer(srcptr)) 33 34 if b := C.sqlite3_backup_init(c.db, destptr, conn.db, srcptr); b != nil { 35 bb := &SQLiteBackup{b: b} 36 runtime.SetFinalizer(bb, (*SQLiteBackup).Finish) 37 return bb, nil 38 } 39 return nil, c.lastError() 40 } 41 42 // Step to backs up for one step. Calls the underlying `sqlite3_backup_step` 43 // function. This function returns a boolean indicating if the backup is done 44 // and an error signalling any other error. Done is returned if the underlying 45 // C function returns SQLITE_DONE (Code 101) 46 func (b *SQLiteBackup) Step(p int) (bool, error) { 47 ret := C.sqlite3_backup_step(b.b, C.int(p)) 48 if ret == C.SQLITE_DONE { 49 return true, nil 50 } else if ret != 0 && ret != C.SQLITE_LOCKED && ret != C.SQLITE_BUSY { 51 return false, Error{Code: ErrNo(ret)} 52 } 53 return false, nil 54 } 55 56 // Remaining return whether have the rest for backup. 57 func (b *SQLiteBackup) Remaining() int { 58 return int(C.sqlite3_backup_remaining(b.b)) 59 } 60 61 // PageCount return count of pages. 62 func (b *SQLiteBackup) PageCount() int { 63 return int(C.sqlite3_backup_pagecount(b.b)) 64 } 65 66 // Finish close backup. 67 func (b *SQLiteBackup) Finish() error { 68 return b.Close() 69 } 70 71 // Close close backup. 72 func (b *SQLiteBackup) Close() error { 73 ret := C.sqlite3_backup_finish(b.b) 74 75 // sqlite3_backup_finish() never fails, it just returns the 76 // error code from previous operations, so clean up before 77 // checking and returning an error 78 b.b = nil 79 runtime.SetFinalizer(b, nil) 80 81 if ret != 0 { 82 return Error{Code: ErrNo(ret)} 83 } 84 return nil 85 }