can you spot the memory leak?

[thephotographer]

Hi,

Ive got a memory leak in the following code, and after months iv still havent been able to fix it. ive just been ignoring it so far, but i really need to get it fixed. In the dealloc i have commented out CGImageRelease(scratchable) as if i leave it in the app crashes. comment it out and it doesnt crash, but theres a leak. im not sure if thats the cause or not.

in instruments 2 of the things it says are

#	Category	Event Type	Timestamp	RefCt	Address	Size	Responsible Library	Responsible Caller
0	CFData	Malloc	01:43.595.727	1	0x11d190	32	EvokkeMagazinev0.55	-[myclassLayer initWithFrame:lineWidth:imageLocation:]
1	CFData	CFRetain	01:43.599.675	2	0x11d190	0	CoreGraphics	CGDataProviderCreateWithCFData

any help solving this would be great! thanks

- (id)initWithFrame:(CGRect)frame lineWidth:(float)lineWidth imageLocation:(NSString*)imageLocation
{
    self = [super initWithFrame:frame];
    if (self) 
    {
        self.transform = CGAffineTransformMakeScale(1, -1);         
        UIImage *scratchableImage = [[UIImage alloc] initWithContentsOfFile:imageLocation];
        if (scratchableImage.size.width != self.frame.size.width)
            scratchable = [self resizeImage:scratchableImage width:self.frame.size.width height:self.frame.size.height].CGImage;
        else
            scratchable = scratchableImage.CGImage;
        width = self.frame.size.width;
		height = self.frame.size.height;
		self.opaque = NO;
		CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceGray();
		
		CFMutableDataRef pixels = CFDataCreateMutable( NULL , width * height );
		alphaPixels = CGBitmapContextCreate( CFDataGetMutableBytePtr( pixels ) , width , height , 8 , width , colorspace , kCGImageAlphaNone );
		provider = CGDataProviderCreateWithCFData(pixels);
		
		CGContextSetFillColorWithColor(alphaPixels, [UIColor blackColor].CGColor);
		CGContextFillRect(alphaPixels, frame);
		CGContextSetStrokeColorWithColor(alphaPixels, [UIColor whiteColor].CGColor);
		CGContextSetLineWidth(alphaPixels, lineWidth);
		CGContextSetLineCap(alphaPixels, kCGLineCapRound);
		
		CGImageRef mask = CGImageMaskCreate(width, height, 8, 8, width, provider, nil, NO);
		scratched = CGImageCreateWithMask(scratchable, mask);
		
		CGImageRelease(mask);
		CGColorSpaceRelease(colorspace);
        
        [scratchableImage release];
        
    }
    return self;
}


- (void)dealloc 
{
	CGContextRelease(alphaPixels);
	//CGImageRelease(scratchable);
	CGDataProviderRelease(provider);
    [super dealloc];
}

[Mogglas]

Originally Posted by thephotographer

Hi,

Ive got a memory leak in the following code, and after months iv still havent been able to fix it. ive just been ignoring it so far, but i really need to get it fixed. In the dealloc i have commented out CGImageRelease(scratchable) as if i leave it in the app crashes. comment it out and it doesnt crash, but theres a leak. im not sure if thats the cause or not.

in instruments 2 of the things it says are

#	Category	Event Type	Timestamp	RefCt	Address	Size	Responsible Library	Responsible Caller
0	CFData	Malloc	01:43.595.727	1	0x11d190	32	EvokkeMagazinev0.55	-[myclassLayer initWithFrame:lineWidth:imageLocation:]
1	CFData	CFRetain	01:43.599.675	2	0x11d190	0	CoreGraphics	CGDataProviderCreateWithCFData

any help solving this would be great! thanks

- (id)initWithFrame:(CGRect)frame lineWidth:(float)lineWidth imageLocation:(NSString*)imageLocation
{
    self = [super initWithFrame:frame];
    if (self) 
    {
        self.transform = CGAffineTransformMakeScale(1, -1);         
        UIImage *scratchableImage = [[UIImage alloc] initWithContentsOfFile:imageLocation];
        if (scratchableImage.size.width != self.frame.size.width)
            scratchable = [self resizeImage:scratchableImage width:self.frame.size.width height:self.frame.size.height].CGImage;
        else
            scratchable = scratchableImage.CGImage;
        width = self.frame.size.width;
		height = self.frame.size.height;
		self.opaque = NO;
		CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceGray();
		
		CFMutableDataRef pixels = CFDataCreateMutable( NULL , width * height );
		alphaPixels = CGBitmapContextCreate( CFDataGetMutableBytePtr( pixels ) , width , height , 8 , width , colorspace , kCGImageAlphaNone );
		provider = CGDataProviderCreateWithCFData(pixels);
		
		CGContextSetFillColorWithColor(alphaPixels, [UIColor blackColor].CGColor);
		CGContextFillRect(alphaPixels, frame);
		CGContextSetStrokeColorWithColor(alphaPixels, [UIColor whiteColor].CGColor);
		CGContextSetLineWidth(alphaPixels, lineWidth);
		CGContextSetLineCap(alphaPixels, kCGLineCapRound);
		
		CGImageRef mask = CGImageMaskCreate(width, height, 8, 8, width, provider, nil, NO);
		scratched = CGImageCreateWithMask(scratchable, mask);
		
		CGImageRelease(mask);
		CGColorSpaceRelease(colorspace);
        
        [scratchableImage release];
        
    }
    return self;
}


- (void)dealloc 
{
	CGContextRelease(alphaPixels);
	//CGImageRelease(scratchable);
	CGDataProviderRelease(provider);
    [super dealloc];
}

could it be the 'pixels' variable?

[thephotographer]

its quite possible thats the issue.. i tried putting CFRelease(pixels); at the end of the init method, didnt fix the issue. but also im not sure ive done it right, im not sure if CFRelease is the right thing to use, but its the best i could find. theres still a leak.

[Mogglas]

Originally Posted by thephotographer

its quite possible thats the issue.. i tried putting CFRelease(pixels); at the end of the init method, didnt fix the issue. but also im not sure ive done it right, im not sure if CFRelease is the right thing to use, but its the best i could find. theres still a leak.

Well, then my tip is: comment out as much as possible. make an empty init, test it. And then uncomment one or a few lines per run. That will make it easy to isolate the leak.

[thephotographer]

Originally Posted by Mogglas

Well, then my tip is: comment out as much as possible. make an empty init, test it. And then uncomment one or a few lines per run. That will make it easy to isolate the leak.

perfect! i should have thought of that... i could comment out pixels as everything refers to it. but i commented out most of the rest of the code, turned pout to be the variable scratched. i then added CGImageRelease(scratched); to my dealloc and its all good now. thanks! i think that was the last memory leak in my app. i cant find any others