writeImageDataToSavedPhotosAlbum Slows Dramatically After A Few Uses

[iSkythe]

I save images to the iPhone's photo album using the api "writeImageDataToSavedPhotosAlbum". However, after several uses (such as 4), it begins to take approximately twice as long each time to save.

I have created a test method to reproduce it, where it saves the exact same image each time. The method is as follows:

-(IBAction)testButton {
    NSData *data = [NSData dataWithContentsOfFile:[[self photosDirectory] stringByAppendingPathComponent:[[self contentsOfPhotoDirectory] objectAtIndex:0]]];
    ALAssetsLibrary *al = [[ALAssetsLibrary alloc] init];
    __block NSDate *date = [[NSDate date] retain];
	[al writeImageDataToSavedPhotosAlbum:data metadata:nil completionBlock:^(NSURL *assetURL, NSError *error) {
        NSLog(@"Saving Time: %g", [[NSDate date] timeIntervalSinceDate:date]);
        [date release];
    }];
    [al release];
}

On a freshly restarted iPhone 4, I get the following save times.

2011-06-01 21:23:13.641 myapp[95:707] Saving Time: 5.30819
2011-06-01 21:23:17.101 myapp[95:707] Saving Time: 1.5311
2011-06-01 21:23:21.916 myapp[95:707] Saving Time: 2.52412
2011-06-01 21:23:25.974 myapp[95:707] Saving Time: 2.85623
2011-06-01 21:23:32.275 myapp[95:707] Saving Time: 4.93484
2011-06-01 21:23:42.024 myapp[95:707] Saving Time: 7.93288
2011-06-01 21:24:00.317 myapp[95:707] Saving Time: 15.8561
2011-06-01 21:24:33.199 myapp[95:707] Saving Time: 29.7571

What is wrong?

[iSkythe]

After more investigating, I found the culprit was allocating memory but never releasing it. I had registered for the ALAssetsLibraryChangedNotification, and in the method that is called I allocated an instance of ALAssetsLibrary, but never released it after enumerating through it (I only released it in the failure block)