Question

I have a iOS project in which I am using ARC in my own classes, but have ARC turned off in other libraries like ASIHTTPRequest.

I’m getting huge memory leaks using the code below to fetch an image from a web server:

-(void)buildPhotoView {

self.photoLibView.hidden = NO;

NSString *assetPathStr = [self.cellData objectForKey:@"AssetThumbPath"];

// get the thumbnail image of the ocPHOTOALBUM from the server and populate the UIImageViews
NSURL *imageURL = [NSURL URLWithString:assetPathStr];

__block ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:imageURL];
__unsafe_unretained ASIHTTPRequest *weakRequest = request;
[weakRequest setCompletionBlock:^{

    // put image into imageView when request complete
    NSData *responseData = [weakRequest responseData];
    UIImage *photoAlbumImage = [[UIImage alloc] initWithData:responseData];
    self.photo1ImageView.image = photoAlbumImage;
}];
[weakRequest setFailedBlock:^{
    NSError *error = [request error];
    NSLog(@"error geting file: %@", error);
}];
[weakRequest startAsynchronous];

}

I’ve modified the sample code from the ASIHTTPRequest example code page to eliminate compiler warnings in Xcode.

How can I get rid of these memory leaks? I only seem to get them when using blocks.

Answer 1

You’re referencing the wrong request variable from inside the completion block. You should reference request in the block (that’s why you declare it with the __block identifier). In fact, you shouldn’t need to declare weakRequest at all.

If you want the request to be kept in memory, store it in an @property (retain) in your class (the one with the buildPhotoView method perhaps).