objective-c - 块每个块文件复制

Question

有没有一种好方法可以使用目标 c 在 Mac OS 中每个块复制一些文件或目录（带有文件和子目录）块？

Answer 1

您可以通过创建 aNSInputStream和 aNSOutputStream并将它们安排在 a 中来为每个块复制一个文件NSRunLoop。然后，当您从输入流中获取字节时，将它们写入缓冲区，当输出流准备好时，您将缓冲区的内容复制到其中。

@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];
}

复制目录的内容需要枚举目录的内容。您可以创建一个NSDirectoryEnumeratorwith的实例-[NSFileManager enumeratorAtPath:]。

一旦你有了枚举器，你调用nextObject然后获取文件属性：

• 如果文件是目录，则在目标目录中创建一个新目录
• If the file is a regular file, you start a file copy task and wait until the completion handler is called.

Answer 2

您可以使用 复制文件或目录-[NSFileManager copyItemAtPath:toPath:error:]。

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);