backup.go raw

   1  // Copyright (C) 2019 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 (destConn *SQLiteConn) Backup(dest string, srcConn *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(destConn.db, destptr, srcConn.db, srcptr); b != nil {
  35  		bb := &SQLiteBackup{b: b}
  36  		runtime.SetFinalizer(bb, (*SQLiteBackup).Finish)
  37  		return bb, nil
  38  	}
  39  	return nil, destConn.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  }
  86