Memory usage climbing when popping out of ALAssetslibrary during enumeration - iphone

Question

I have an issue where I see memory usage climbing (but no obvious leaks in Instruments) in my app.
I have a test project with two viewControllers: MainViewController and PhotoViewController. The MainViewController contains a single button that simply pushes PhotoViewController via a uinavigationcontroller pushViewController method.
In PhotoViewController, I am using the ALAssetsLibrary to populate a UITableView with images. I essentially do this in two parts. First, I check to see what assetGroups are available, as I need to show images from the Camera Roll and the Photolibrary. Once that is done, I call another method to enumerate through the actual Assets.
Here is the strange behavior: if I push the PhotoViewController and let it finish the entire enumeration and populate the UITableView, and then pop out back to the MainViewController, everything is fine.
However, if I repeatedly and rapidly push and pop out of the PhotoViewCOntroller (while it hasn't yet finished enumerating and populating the UITableiew),then I see my memory usage gradually climbing until the app finally dies. I don't see any obvious leaks in Instruments.
I don't know the relevant code, but here are two methods that use to enumerate. Of course, in dealloc, I am releasing the relevant ivars.
Is there some way to cancel an enumeration upon pop?
Just as a note, I am basing my test code off this project (https://github.com/elc/ELCImagePickerController), although heavily customized. However, I just tested with that code and the same issue happens. Note that you would only see memory usage climb if you have sufficient ALAssets to enumerate. If there are too few, then it would finish enumerating beforeyou couldpop back out.
Thank you!
- (void)getAssetGroups
{
// Load Albums into assetGroups
dispatch_async(dispatch_get_main_queue(), ^
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
// Group enumerator Block
void (^assetGroupEnumerator)(ALAssetsGroup *, BOOL *) = ^(ALAssetsGroup *group, BOOL *stop)
{
if (group == nil)
{
// check what data is available
if([savedPhotosGroup numberOfAssets] > 0 && [libraryGroup numberOfAssets] > 0)
{
// User has both Camera Roll and Photo Library albums
self.tableData = [NSMutableDictionary dictionaryWithObjectsAndKeys:
savedPhotoAssets, NSLocalizedString(#"PHOTOPICKER_CAMERAROLL", nil),
libraryPhotosAssets, NSLocalizedString(#"PHOTOPICKER_PHOTOLIBRARY", nil),
nil];
self.sectionKeys = [NSArray arrayWithObjects:NSLocalizedString(#"PHOTOPICKER_CAMERAROLL", nil), NSLocalizedString(#"PHOTOPICKER_PHOTOLIBRARY", nil), nil];
}
else if([libraryGroup numberOfAssets] == 0)
{
// User only has Camera Roll
self.tableData = [NSMutableDictionary dictionaryWithObjectsAndKeys:
savedPhotoAssets, NSLocalizedString(#"PHOTOPICKER_CAMERAROLL", nil),
nil];
self.sectionKeys = [NSArray arrayWithObjects:NSLocalizedString(#"PHOTOPICKER_CAMERAROLL", nil), nil];
}
else
{
//User only has Photo Library
self.tableData = [NSMutableDictionary dictionaryWithObjectsAndKeys:
libraryPhotosAssets, NSLocalizedString(#"PHOTOPICKER_PHOTOLIBRARY", nil),
nil];
self.sectionKeys = [NSArray arrayWithObjects:NSLocalizedString(#"PHOTOPICKER_PHOTOLIBRARY", nil), nil];
}
NSLog(#"Done enumerating groups");
[self performSelectorInBackground:#selector(enumeratePhotos) withObject:nil];
[self.tview performSelector:#selector(reloadData) withObject:nil afterDelay:1];
return;
}
ALAssetsGroupType groupType = [[group valueForProperty:ALAssetsGroupPropertyType] unsignedIntValue];
if(groupType == ALAssetsGroupSavedPhotos)
{
self.savedPhotosGroup = group;
}
else if(groupType == ALAssetsGroupLibrary)
{
self.libraryGroup = group;
}
};
// Group Enumerator Failure Block
void (^assetGroupEnumberatorFailure)(NSError *) = ^(NSError *error) {
NSLog(#"A problem occured %#", [error description]);
};
// Enumerate Albums
[library enumerateGroupsWithTypes: ALAssetsGroupSavedPhotos | ALAssetsGroupLibrary
usingBlock:assetGroupEnumerator
failureBlock:assetGroupEnumberatorFailure];
NSLog(#"Draining pool");
[pool drain];
});
}
-(void)enumeratePhotos {
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
NSLog(#"enumerating photos");
[savedPhotosGroup enumerateAssetsUsingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop)
{
if(result == nil)
{
return;
}
CustomAsset *customAsset = [[[CustomAsset alloc] initWithAsset:result] autorelease];
[customAsset setParent:self];
[savedPhotoAssets addObject:customAsset];
}];
[libraryGroup enumerateAssetsUsingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop)
{
if(result == nil)
{
return;
}
CustomAsset *customAsset = [[[CustomAsset alloc] initWithAsset:result] autorelease];
[customAsset setParent:self];
[libraryPhotosAssets addObject:customAsset];
}];
NSLog(#"done enumerating photos");
[tview performSelectorOnMainThread:#selector(reloadData) withObject:nil waitUntilDone:NO];
// only do this if I want to re-select some assets
if(assetsToRestore)
{
for(NSDictionary *dict in assetsToRestore)
{
NSIndexPath *indexPathToRestore = [dict objectForKey:#"selectedAssetIndexPath"];
int tagToRestore = [[dict objectForKey:#"selectedAssetTag"] intValue];
[self selectAssetWithIndexPath:indexPathToRestore andIndex:tagToRestore];
}
}
[pool drain]; }

Answer 1

correct me if i'm wrong, I thought using autorelease pools was supposed to be done like this now:
#autoreleasepool {
(statements)
}
That worked for me.