FICUUIDBytesFromMD5HashOfString causing crash

[robmontesinos]

I am getting a crash on the MD5 line in FICDPhoto.m -> line 170

The crash occurred on scrolling a tableview with images from website after about four screen - fast scrolling the first time and crashed on slow scrolling. exc_bad_access - and then on another attempt without changing anything, it did not crash at all and the scrolling was much faster than what I had before FastImageCache.

Any help would be appreciated.

pragma mark - FICImageCacheEntity

• (NSString *)UUID {
  if (_UUID == nil) {
  // MD5 hashing is expensive enough that we only want to do it once - CRASH LINE BELOW
  CFUUIDBytes UUIDBytes = FICUUIDBytesFromMD5HashOfString([_sourceImageURL absoluteString]);
  _UUID = FICStringWithUUIDBytes(UUIDBytes);
  }

  return _UUID;
  }

Could you please zip up the images you're using and upload them somewhere so we can test with your images? We haven't encountered this issue yet.

[mallorypaine]

It looks like you have a bug in your code. The second line of what you pasted is "if (UUID == nil)". This should instead be "if (_UUID == nil)", right?

[mallorypaine]

As far as the performance issue is concerned, it's hard to comment without knowing more. Can you paste the code that sets up your FICImageFormats?

[jjxtra]

The latest code in github has if (_UUID == nil). Maybe a nil check needs to be done on sourceImageURL?

[robmontesinos]

Thanks for the quick response guys.

Good catch on UUID == nil having to be _UUID == nil. I don't know why the underscore got dropped - I had _UUID in my code. Weird. Maybe I knocked it out by accident. Still crashing after scrolling about two screens.

AppDelegate method

• (void)configureFastImageCache {
  NSMutableArray *mutableImageFormats = [NSMutableArray array];

  // square image format
  NSInteger squareImageFormatMaximumCount = 400;
  FICImageFormatDevices squareImageFormatDevices = FICImageFormatDevicePhone | FICImageFormatDevicePad;

  FICImageFormat *squareImageFormat = [FICImageFormat formatWithName:FICDPhotoSquareImageFormatName family:FICDPhotoImageFormatFamily imageSize:FICDPhotoSquareImageSize isOpaque:YES maximumCount:squareImageFormatMaximumCount devices:squareImageFormatDevices];

  [mutableImageFormats addObject:squareImageFormat];

  if ([UIViewController instancesRespondToSelector:@selector(preferredStatusBarStyle)]) {
  // Pixel image format
  NSInteger pixelImageFormatMaximumCount = 1000;
  FICImageFormatDevices pixelImageFormatDevices = FICImageFormatDevicePhone | FICImageFormatDevicePad;

  FICImageFormat *pixelImageFormat = [FICImageFormat formatWithName:FICDPhotoPixelImageFormatName family:FICDPhotoImageFormatFamily imageSize:FICDPhotoPixelImageSize isOpaque:YES maximumCount:pixelImageFormatMaximumCount devices:pixelImageFormatDevices];
  
  [mutableImageFormats addObject:pixelImageFormat];
  

  }

  // configure image cache
  FICImageCache *sharedImageCache = [FICImageCache sharedImageCache];
  [sharedImageCache setDelegate:self];
  [sharedImageCache setFormats:mutableImageFormats];
  }

Unfortunately, we don't really have the ability to check over every person's use of Fast Image Cache. We haven't seen any crashes or performance issues in the demo app or in Path, which uses FIC extensively. If it's the demo app that's crashing, we either need specifics about what's happening.

As it stands, nobody else seems to be experiencing crashes, so I'm going to close this issue for now.