ios - 使用 AFNetworking 下载时泄漏

Question

基本上当文件下载完成后，内存中就会有一些永远不会被释放的“东西”。这是导致该问题的代码的一个简单示例，内存上升到大约 50mb，它只是坐在那里，永远不会被释放(见下面的屏幕截图)。知道发生了什么事吗？

-(void)download {
    NSString* urlString = @"http://download.thinkbroadband.com/50MB.zip";
    NSMutableURLRequest* request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:urlString]];
    AFHTTPRequestOperation* operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];

    [operation setDownloadProgressBlock:^(NSUInteger bytesRead, long long totalBytesRead, long long totalBytesExpectedToRead) {
        NSLog(@"%lldmb of %lldmb downloaded", totalBytesRead / 1024 / 1024, totalBytesExpectedToRead / 1024 / 1024);
    }];

    [operation setCompletionBlockWithSuccess:^(__weak AFHTTPRequestOperation *operation, id responseObject) {
        NSLog(@"Download completed.");
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Error: %@", error.localizedDescription);
    }];

    [operation start];
}

下载前:

下载后:

Answer 1

在我自己使用 AFNetworking 2.5 在 iOS 8.1 上进行的测试中，这似乎是 Debug模式而非 Release模式的情况。鉴于您的代码没有按原样运行，我做了以下测试用例:

- (IBAction)startDownload:(UIButton *)sender 
{
    NSString *downloadURLString = @"http://mirror.internode.on.net/pub/test/50meg.test";
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:downloadURLString]];
    AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
    manager.responseSerializer = [AFHTTPResponseSerializer serializer];
    AFHTTPRequestOperation *operation = [manager HTTPRequestOperationWithRequest:request success:^(AFHTTPRequestOperation *operation, id responseObject) {
        NSLog(@"Download succeeded.");
        self.stateLabel.text = @"Download succeeded.";
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Download failed with error: %@", error);
        self.stateLabel.text = @"Download failed.";
    }];

    [operation setDownloadProgressBlock:^(NSUInteger bytesRead, long long totalBytesRead, long long totalBytesExpectedToRead) {
        NSLog(@"Bytes read: %lu", bytesRead);
        NSLog(@"Total bytes read %lld", totalBytesRead);
        NSLog(@"Total progress: %Lf", (long double)totalBytesRead / totalBytesExpectedToRead);
        self.progressView.progress = (long double)totalBytesRead / totalBytesExpectedToRead;
    }];

    NSLog(@"Starting download.");
    NSOperationQueue *downloadQueue = [[NSOperationQueue alloc] init];
    [downloadQueue addOperation:operation];
}

使用这段代码，一旦下载完成，在 Release模式下，内存使用率会回落到下载前的水平。