ARC does not release CALayer - ios

Question

I have a code block which aims to capture snapshot of pdf based custom views for each page. To accomplish it I'll create view controller in a loop and then iterate. The problem is even view controller released custom view doesn't released and look like live on Instruments tool. As a result for loop iterates a lot so it breaks the memory (up to 500MB for 42 living) and crashes.
Here is the iteration code;
do
{
__pageDictionary = CFDictionaryGetValue(_allPages,
__pageID);
CUIPageViewController *__pageViewController = [self _pageWithID:__pageID];
[__pageViewController addMainLayers];
[[APP_DELEGATE assetManager] temporarilyPasteSnapshotSource:__pageViewController.view];
UIImage *__snapshotImage = [__pageViewController captureSnapshot];
[[AOAssetManager sharedManager] saveImage:__snapshotImage
forPublicationBundle:_publicationTileViewController.publication.bundle
pageID:(__bridge NSString *)__pageID];
[[APP_DELEGATE assetManager] removePastedSnapshotSource:__pageViewController.view];
__snapshotImage = nil;
__pageViewController = nil;
ind += 6 * 0.1 / CFDictionaryGetCount(_allPages);
}
while (![(__bridge NSString *)(__pageID = CFDictionaryGetValue(__pageDictionary,
kMFMarkupKeyPageNextPageID)) isMemberOfClass:[NSNull class]]);
_generatingSnapshots = NO;
And here the captureSnapshot method;
- (UIImage *)captureSnapshot
{
CGRect rect = [self.view bounds];
UIGraphicsBeginImageContextWithOptions(rect.size,YES,0.0f);
context = UIGraphicsGetCurrentContext();
[self.view.layer renderInContext:context];
UIImage *capturedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return capturedImage;
}
Instruments;
Edit for further details:
Below code is from CUIPDFView a subclass of UIView;
- (void)drawRect:(CGRect)rect
{
[self drawInContext:UIGraphicsGetCurrentContext()];
}
-(void)drawInContext:(CGContextRef)context
{
CGRect drawRect = CGRectMake(self.bounds.origin.x, self.bounds.origin.y,self.bounds.size.width, self.bounds.size.height);
CGContextSetRGBFillColor(context, 1.0000, 1.0000, 1.0000, 1.0f);
CGContextFillRect(context, drawRect);
// PDF page drawing expects a Lower-Left coordinate system, so we flip the coordinate system
// before we start drawing.
CGContextTranslateCTM(context, 0.0, self.bounds.size.height);
CGContextScaleCTM(context, 1.0, -1.0);
// Grab the first PDF page
CGPDFPageRef page = CGPDFDocumentGetPage(_pdfDocument, _pageNumberToUse);
// We're about to modify the context CTM to draw the PDF page where we want it, so save the graphics state in case we want to do more drawing
CGContextSaveGState(context);
// CGPDFPageGetDrawingTransform provides an easy way to get the transform for a PDF page. It will scale down to fit, including any
// base rotations necessary to display the PDF page correctly.
CGAffineTransform pdfTransform = CGPDFPageGetDrawingTransform(page, kCGPDFCropBox, self.bounds, 0, true);
// And apply the transform.
CGContextConcatCTM(context, pdfTransform);
// Finally, we draw the page and restore the graphics state for further manipulations!
CGContextDrawPDFPage(context, page);
CGContextRestoreGState(context);
}
When I delete drawRect method implementation, memory allocation problem dismiss but obviously it can't print the pdf.

Answer 1

Try putting an #autoreleasepool inside your loop:
do
{
#autoreleasepool
{
__pageDictionary = CFDictionaryGetValue(_allPages,
__pageID);
CUIPageViewController *__pageViewController = [self _pageWithID:__pageID];
[__pageViewController addMainLayers];
[[APP_DELEGATE assetManager] temporarilyPasteSnapshotSource:__pageViewController.view];
UIImage *__snapshotImage = [__pageViewController captureSnapshot];
[[AOAssetManager sharedManager] saveImage:__snapshotImage
forPublicationBundle:_publicationTileViewController.publication.bundle
pageID:(__bridge NSString *)__pageID];
[[APP_DELEGATE assetManager] removePastedSnapshotSource:__pageViewController.view];
__snapshotImage = nil;
__pageViewController = nil;
ind += 6 * 0.1 / CFDictionaryGetCount(_allPages);
}
}
while (![(__bridge NSString *)(__pageID = CFDictionaryGetValue(__pageDictionary,
This will flush the autorelease pool each time through the loop, releasing all the autoreleased objects.

Answer 2

I would be surprised if this is actually a problem with ARC. An object that is still alive still has a strong reference to the layer.
What does [AOAssetManager saveImage:...] do with the image. Are you sure it is not holding onto it?
Is _pageWithID: doing something that is keeping a pointer to CUIPageViewController around?