每塊文件複製塊

Question

有沒有一種很好的方法來複制一些文件或目錄（包括文件和子目錄）在Mac OS塊與目標c？

Answer 1

您可以通過創建一個NSInputStream和NSOutputStream並在NSRunLoop安排將它們拷貝每塊的文件。然後，當您從輸入流獲取字節時，將它們寫入緩衝區，並在輸出流準備就緒後，將緩衝區的內容複製到其中。

@synthesize numberOfBytesTransferred = _numberOfBytesTransferred; 

static const NSUInteger blockSize = 65536; // should be adjusted 

- (void)startWithSourcePath:(NSString *)srcPath 
      destinationPath:(NSString *)dstPath 
      completionHandler:(void (^)(NSUInteger, NSError *))completionHandler 
{ 
    _buffer = malloc(blockSize); 
    _numberOfBytesTransferred = _bufferLength = _bufferOffset = 0; 
    _completionHandler = [completionHandler copy]; 
    _srcStream = [[NSInputStream alloc] initWithFileAtPath:srcPath]; 
    _dstStream = [[NSOutputStream alloc] initToFileAtPath:dstPath append:NO]; 
    _srcStream.delegate = self; 
    _dstStream.delegate = self; 
    [_srcStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes]; 
    [_dstStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes]; 
    [_srcStream open]; 
    [_dstStream open]; 
} 

- (void)processStreams 
{  
    if (_srcStream.hasBytesAvailable && ! _bufferLength) 
     _bufferLength = [_srcStream read:_buffer maxLength:blockSize]; 

    if (_dstStream.hasSpaceAvailable && _bufferLength) { 
     NSInteger length = [_dstStream write:_buffer + _bufferOffset maxLength:_bufferLength]; 
     _bufferOffset += length; 
     _bufferLength -= length; 
    } 

    if (_bufferOffset && !_bufferLength) { 
     [self willChangeValueForKey:@"numberOfBytesTransferred"]; 
     _numberOfBytesTransferred += _bufferOffset; 
     _bufferOffset = 0; 
     [self didChangeValueForKey:@"numberOfBytesTransferred"]; 
    } 

    if (_dstStream.hasSpaceAvailable && NSStreamStatusAtEnd == _srcStream.streamStatus) { 
     [_srcStream close]; 
     [_dstStream close]; 
     _completionHandler(_numberOfBytesTransferred, nil); 
    } 
} 

- (void)cancel 
{ 
    [_srcStream close]; 
    [_dstStream close]; 
} 

- (void)pause 
{ 
    _paused = YES; 
} 

- (void)resume 
{ 
    _paused = NO; 
    [self processStreams]; 
} 

- (void)stream:(NSStream *)stream handleEvent:(NSStreamEvent)eventCode 
{ 
    if (NSStreamEventErrorOccurred == eventCode) { 
     [_srcStream close]; 
     [_dstStream close]; 
     _completionHandler(_numberOfBytesTransferred, stream.streamError); 
     return; 
    } 

    if (! _paused) 
     [self processStreams]; 
} 

複製一個目錄的內容將需要枚舉整個目錄的內容。您可以使用-[NSFileManager enumeratorAtPath:]創建NSDirectoryEnumerator的實例。

一旦你的枚舉，你叫nextObject然後拿到文件屬性：

• 如果該文件是一個目錄，您可以創建在目標目錄
• 一個新的目錄如果該文件是一個普通的文件，您將啓動文件複製任務並等待直到完成處理程序被調用。

Answer 2

您可以使用-[NSFileManager copyItemAtPath:toPath:error:]複製文件或目錄。

NSFileManager *fileManager = [NSFileManager defaultManager]; 
NSString *srcPath = @"/Users/nicolas/Documents/Xcode projects"; 
NSString *dstPath = @"/Users/nicolas/Desktop/Backup/Xcode projects"; 
NSError *error; 
if (! [fileManager copyItemAtPath:srcPath toPath:dstPath error:&error]) 
    NSLog(@"Copy error: %@", error);