NSPOSIXErrorDomain Code=12“无法分配内存”在3G网络中

Question

我正在尝试在 iPhone 应用程序中发送 FTP 服务器上的文件。 在 WiFi 和 GSM:EDGE 网络中似乎一切正常，但在 3G 网络中出现错误（并非总是如此，但经常出现）：

错误域=NSPOSIXErrorDomain Code=12 "该操作不能 完全的。无法分配内存”

出现错误的代码下方：

- (void)stream:(NSStream*)aStream handleEvent:(NSStreamEvent)eventCode {

    switch( eventCode ) {
        case NSStreamEventHasSpaceAvailable: {
            if( _readDataOffset == _readDataLimit ) {
                NSInteger readDataLen = [_readStream read:[_readData mutableBytes] maxLength:kReadDataLength];
                NSLog(@"readDataLen is %d",readDataLen);
                if( -1 == readDataLen ) {
                    _error = [[_readStream streamError] retain];
                    _keepRunning = NO;
                } else if( 0 == readDataLen ) {
                    _keepRunning = NO;
                } else {
                    _readDataOffset = 0;
                    _readDataLimit = readDataLen;
                }
            }

            if( _readDataOffset != _readDataLimit ) {
                NSOutputStream* writeStream = (NSOutputStream*)aStream;

                uint8_t *buffer = (void *)[_readData bytes];

          // vvvv and here  the value of writtenDataLen is often -1 (but only on 3G network)
                NSInteger writtenDataLen = [writeStream write:&buffer[_readDataOffset] maxLength:_readDataLimit - _readDataOffset]; 


                if( writtenDataLen > 0 ) {
                    _readDataOffset += writtenDataLen;
                    _writtenDataLen += writtenDataLen;
                    [self ftpPutDidWriteInternal];
                } else if( -1 == writtenDataLen ) {
                    _error = [[writeStream streamError] retain];
                    _keepRunning = NO;
                }
            }

        } break;
        case NSStreamEventErrorOccurred: {
            _error = [aStream.streamError retain];
            _keepRunning = NO;
        } break;
    }    
}

重要的是，整个发送是在单独的线程中完成的，该线程有自己的 NSAutoreleasePool。 有人遇到这个问题吗？有什么建议吗？我将不胜感激。

更新： 我刚刚检查了流行的 iPhone 应用程序“FTP On The Go”在 3G 网络中发送文件时也遇到了相同（？）的问题！没有处理任何错误，但传输停止。

更新2： 我不敢相信，但这是真的： SimpleFTPSample 来自苹果也受到该问题的影响。

Answer 1

这就是 - 解决方案（或者更确切地说是解决方法）：

您应该将 writeStream 的属性设置为 false，以关闭默认的持久连接

CFWriteStreamSetProperty( (CFWriteStreamRef)writeStreamRef, kCFStreamPropertyFTPAttemptPersistentConnection, kCFBooleanFalse ) ;

Answer 2

已通过使用请求操作 (NSMutableUrlConnection) 和 @autorelease{} 作为主函数解决了此错误

- (void)main
 NSURLConnection* connection;
    @autoreleasepool //urgently needed for 3G upload
    {

        self.currentRequest = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:@"test.php"]];
        [self.currentRequest setHTTPMethod:@"PUT"];

        [self.currentRequest setHTTPBody:self.data];//inpustStream doesn't work

        connection = [NSURLConnection connectionWithRequest:self.currentRequest delegate:self];
        [connection start];

    }//end autorelease pool

        do 
        {

            [[NSRunLoop currentRunLoop] runMode: NSDefaultRunLoopMode beforeDate: [NSDate distantFuture]];
            if ([self isCancelled])
            {
                connection          = nil;
                isFailed = YES;
                break;
            }
            self.status(statusUpdateMessage);
        } 
        while (!isFailed && !isCompleted);
        [timer invalidate];//test
        timer = nil;

//corresponding of status via blocks
        self.completed(!isFailed);
        self.status(isFailed ? errorMessage : @"Completed");
        if (isFailed)
        {
            self.failed(errorMessage != nil ? errorMessage : @"Undefined error");
        }

        self.data = nil;
        self.currentRequest = nil;

        connection = nil;

}