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  }