Question

我使用NSInputstream＆amp; NSOutputstream设置连接并发送数据。我的流对象具有打开和关闭流的功能。我使用以下代码：

@interface Stream()
{
    NSInputStream *inputStream;
    NSOutputStream *outputStream;
}

-(id)init
{
    self = [super init];
    if (self)
    {
        inputStream = nil;
        outputStream = nil;
    }
    return self;
}

-(int)streamOpenWithIp:(NSString *)ip withPortNumber:(int)portNumber;
{
        CFReadStreamRef readStream;
        CFWriteStreamRef writeStream;

        CFStreamCreatePairWithSocketToHost(kCFAllocatorDefault, (__bridge CFStringRef)ip, portNumber, &readStream, &writeStream);

        if(readStream && writeStream)
        { 
            //Setup inpustream
            inputStream = (__bridge NSInputStream *)readStream;
            [inputStream setDelegate:self];
            [inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
            [inputStream open];

            //Setup outputstream
            outputStream = (__bridge NSOutputStream *)writeStream;
            [outputStream setDelegate:self];
            [outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
            [outputStream open];
        }
}

- (int)streamClose;
{ 
        CFReadStreamSetProperty((__bridge CFReadStreamRef)(inputStream), kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);
        CFReadStreamSetProperty((__bridge CFReadStreamRef)(outputStream), kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);

        //Close and reset inputstream
        [inputStream setDelegate:nil];
        [inputStream close];
        [inputStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
        inputStream = nil;

        //Close and reset outputstream
        [outputStream setDelegate:nil];
        [outputStream close];
        [outputStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
        outputStream = nil;
}

当我多次打开和关闭流时，此代码可以正常工作。当我使用Instruments检查我的应用程序内存泄漏时，它说函数CFStreamCreatePairWithSocketToHost泄漏了72％的内存。有人知道我做错了什么吗？我无法理解。

Answer 1

在CFRelease((CFStreamRef)inputStream);方法中添加CFRelease((CFStreamRef)outputStream);和streamClose。

当CFStreamCreatePairWithSocketToHost返回时，readStream和writeStream的所有权会传递给您：

Ownership follows the Create Rule in Memory Management Programming Guide for Core Foundation.

即使使用ARC，也需要明确释放Core Foundation对象：

The compiler does not automatically manage the lifetimes of Core Foundation objects; you
must call CFRetain and CFRelease (or the corresponding type-specific variants) as dictated 
by the Core Foundation memory management rules (see Memory Management Programming Guide 
for Core Foundation).

或者，更改此行（以及outputStream的相应行）：

inputStream = (__bridge NSInputStream *)readStream;

到：

inputStream = (__bridge_transfer NSInputStream *)readStream;

这是因为readStream具有ARC不知道的优秀保留计数。通过给ARC指定此指针的所有权，您授予它在适当时间释放指针的权限。进一步阅读：1，2

iOS中的CFStreamCreatePairWithSocketToHost内存泄漏

1 个答案: