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ASCollectionView.mm
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//
// ASCollectionView.mm
// Texture
//
// Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the /ASDK-Licenses directory of this source tree. An additional
// grant of patent rights can be found in the PATENTS file in the same directory.
//
// Modifications to this file made after 4/13/2017 are: Copyright (c) 2017-present,
// Pinterest, Inc. Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
#import <AsyncDisplayKit/ASAssert.h>
#import <AsyncDisplayKit/ASBatchFetching.h>
#import <AsyncDisplayKit/ASDelegateProxy.h>
#import <AsyncDisplayKit/ASCellNode+Internal.h>
#import <AsyncDisplayKit/ASCollectionElement.h>
#import <AsyncDisplayKit/ASCollectionInternal.h>
#import <AsyncDisplayKit/ASCollectionLayout.h>
#import <AsyncDisplayKit/ASCollectionNode+Beta.h>
#import <AsyncDisplayKit/ASCollections.h>
#import <AsyncDisplayKit/ASCollectionViewLayoutController.h>
#import <AsyncDisplayKit/ASCollectionViewLayoutFacilitatorProtocol.h>
#import <AsyncDisplayKit/ASCollectionViewFlowLayoutInspector.h>
#import <AsyncDisplayKit/ASDataController.h>
#import <AsyncDisplayKit/ASDisplayNodeExtras.h>
#import <AsyncDisplayKit/ASDisplayNode+FrameworkPrivate.h>
#import <AsyncDisplayKit/ASDisplayNode+Subclasses.h>
#import <AsyncDisplayKit/ASElementMap.h>
#import <AsyncDisplayKit/ASInternalHelpers.h>
#import <AsyncDisplayKit/UICollectionViewLayout+ASConvenience.h>
#import <AsyncDisplayKit/ASRangeController.h>
#import <AsyncDisplayKit/_ASCollectionViewCell.h>
#import <AsyncDisplayKit/_ASDisplayLayer.h>
#import <AsyncDisplayKit/_ASCollectionReusableView.h>
#import <AsyncDisplayKit/ASPagerNode.h>
#import <AsyncDisplayKit/ASSectionContext.h>
#import <AsyncDisplayKit/ASCollectionView+Undeprecated.h>
#import <AsyncDisplayKit/_ASHierarchyChangeSet.h>
#import <AsyncDisplayKit/CoreGraphics+ASConvenience.h>
#import <AsyncDisplayKit/ASLayout.h>
#import <AsyncDisplayKit/ASThread.h>
/**
* A macro to get self.collectionNode and assign it to a local variable, or return
* the given value if nil.
*
* Previously we would set ASCollectionNode's dataSource & delegate to nil
* during dealloc. However, our asyncDelegate & asyncDataSource must be set on the
* main thread, so if the node is deallocated off-main, we won't learn about the change
* until later on. Since our @c collectionNode parameter to delegate methods (e.g.
* collectionNode:didEndDisplayingItemWithNode:) is nonnull, it's important that we never
* unintentionally pass nil (this will crash in Swift, in production). So we can use
* this macro to ensure that our node is still alive before calling out to the user
* on its behalf.
*/
#define GET_COLLECTIONNODE_OR_RETURN(__var, __val) \
ASCollectionNode *__var = self.collectionNode; \
if (__var == nil) { \
return __val; \
}
#define ASFlowLayoutDefault(layout, property, default) \
({ \
UICollectionViewFlowLayout *flowLayout = ASDynamicCast(layout, UICollectionViewFlowLayout); \
flowLayout ? flowLayout.property : default; \
})
/// What, if any, invalidation should we perform during the next -layoutSubviews.
typedef NS_ENUM(NSUInteger, ASCollectionViewInvalidationStyle) {
/// Perform no invalidation.
ASCollectionViewInvalidationStyleNone,
/// Perform invalidation with animation (use an empty batch update).
ASCollectionViewInvalidationStyleWithoutAnimation,
/// Perform invalidation without animation (use -invalidateLayout).
ASCollectionViewInvalidationStyleWithAnimation,
};
static const NSUInteger kASCollectionViewAnimationNone = UITableViewRowAnimationNone;
/// Used for all cells and supplementaries. UICV keys by supp-kind+reuseID so this is plenty.
static NSString * const kReuseIdentifier = @"_ASCollectionReuseIdentifier";
#pragma mark -
#pragma mark ASCollectionView.
@interface ASCollectionView () <ASRangeControllerDataSource, ASRangeControllerDelegate, ASDataControllerSource, ASCellNodeInteractionDelegate, ASDelegateProxyInterceptor, ASBatchFetchingScrollView, ASCALayerExtendedDelegate, UICollectionViewDelegateFlowLayout> {
ASCollectionViewProxy *_proxyDataSource;
ASCollectionViewProxy *_proxyDelegate;
ASDataController *_dataController;
ASRangeController *_rangeController;
ASCollectionViewLayoutController *_layoutController;
id<ASCollectionViewLayoutInspecting> _defaultLayoutInspector;
__weak id<ASCollectionViewLayoutInspecting> _layoutInspector;
NSHashTable<_ASCollectionViewCell *> *_cellsForVisibilityUpdates;
NSHashTable<ASCellNode *> *_cellsForLayoutUpdates;
id<ASCollectionViewLayoutFacilitatorProtocol> _layoutFacilitator;
CGFloat _leadingScreensForBatching;
// When we update our data controller in response to an interactive move,
// we don't want to tell the collection view about the change (it knows!)
BOOL _updatingInResponseToInteractiveMove;
BOOL _inverted;
NSUInteger _superBatchUpdateCount;
BOOL _isDeallocating;
ASBatchContext *_batchContext;
CGSize _lastBoundsSizeUsedForMeasuringNodes;
NSMutableSet *_registeredSupplementaryKinds;
// CountedSet because UIKit may display the same element in multiple cells e.g. during animations.
NSCountedSet<ASCollectionElement *> *_visibleElements;
CGPoint _deceleratingVelocity;
BOOL _zeroContentInsets;
ASCollectionViewInvalidationStyle _nextLayoutInvalidationStyle;
/**
* If YES, the `UICollectionView` will reload its data on next layout pass so we should not forward any updates to it.
* Rationale:
* In `reloadData`, a collection view invalidates its data and marks itself as needing reload, and waits until `layoutSubviews` to requery its data source.
* This can lead to data inconsistency problems.
* Say you have an empty collection view. You call `reloadData`, then immediately insert an item into your data source and call `insertItemsAtIndexPaths:[0,0]`.
* You will get an assertion failure saying `Invalid number of items in section 0.
* The number of items after the update (1) must be equal to the number of items before the update (1) plus or minus the items added and removed (1 added, 0 removed).`
* The collection view never queried your data source before the update to see that it actually had 0 items.
*/
BOOL _superIsPendingDataLoad;
/**
* It's important that we always check for batch fetching at least once, but also
* that we do not check for batch fetching for empty updates (as that may cause an infinite
* loop of batch fetching, where the batch completes and performBatchUpdates: is called without
* actually making any changes.) So to handle the case where a collection is completely empty
* (0 sections) we always check at least once after each update (initial reload is the first update.)
*/
BOOL _hasEverCheckedForBatchFetchingDueToUpdate;
/**
* Counter used to keep track of nested batch updates.
*/
NSInteger _batchUpdateCount;
/**
* Keep a strong reference to node till view is ready to release.
*/
ASCollectionNode *_keepalive_node;
struct {
unsigned int scrollViewDidScroll:1;
unsigned int scrollViewWillBeginDragging:1;
unsigned int scrollViewDidEndDragging:1;
unsigned int scrollViewWillEndDragging:1;
unsigned int scrollViewDidEndDecelerating:1;
unsigned int collectionViewWillDisplayNodeForItem:1;
unsigned int collectionViewWillDisplayNodeForItemDeprecated:1;
unsigned int collectionViewDidEndDisplayingNodeForItem:1;
unsigned int collectionViewShouldSelectItem:1;
unsigned int collectionViewDidSelectItem:1;
unsigned int collectionViewShouldDeselectItem:1;
unsigned int collectionViewDidDeselectItem:1;
unsigned int collectionViewShouldHighlightItem:1;
unsigned int collectionViewDidHighlightItem:1;
unsigned int collectionViewDidUnhighlightItem:1;
unsigned int collectionViewShouldShowMenuForItem:1;
unsigned int collectionViewCanPerformActionForItem:1;
unsigned int collectionViewPerformActionForItem:1;
unsigned int collectionViewWillBeginBatchFetch:1;
unsigned int shouldBatchFetchForCollectionView:1;
unsigned int collectionNodeWillDisplayItem:1;
unsigned int collectionNodeDidEndDisplayingItem:1;
unsigned int collectionNodeShouldSelectItem:1;
unsigned int collectionNodeDidSelectItem:1;
unsigned int collectionNodeShouldDeselectItem:1;
unsigned int collectionNodeDidDeselectItem:1;
unsigned int collectionNodeShouldHighlightItem:1;
unsigned int collectionNodeDidHighlightItem:1;
unsigned int collectionNodeDidUnhighlightItem:1;
unsigned int collectionNodeShouldShowMenuForItem:1;
unsigned int collectionNodeCanPerformActionForItem:1;
unsigned int collectionNodePerformActionForItem:1;
unsigned int collectionNodeWillBeginBatchFetch:1;
unsigned int collectionNodeWillDisplaySupplementaryElement:1;
unsigned int collectionNodeDidEndDisplayingSupplementaryElement:1;
unsigned int shouldBatchFetchForCollectionNode:1;
// Interop flags
unsigned int interop:1;
unsigned int interopWillDisplayCell:1;
unsigned int interopDidEndDisplayingCell:1;
unsigned int interopWillDisplaySupplementaryView:1;
unsigned int interopdidEndDisplayingSupplementaryView:1;
} _asyncDelegateFlags;
struct {
unsigned int collectionViewNodeForItem:1;
unsigned int collectionViewNodeBlockForItem:1;
unsigned int collectionViewNodeForSupplementaryElement:1;
unsigned int numberOfSectionsInCollectionView:1;
unsigned int collectionViewNumberOfItemsInSection:1;
unsigned int collectionNodeNodeForItem:1;
unsigned int collectionNodeNodeBlockForItem:1;
unsigned int nodeModelForItem:1;
unsigned int collectionNodeNodeForSupplementaryElement:1;
unsigned int collectionNodeNodeBlockForSupplementaryElement:1;
unsigned int collectionNodeSupplementaryElementKindsInSection:1;
unsigned int numberOfSectionsInCollectionNode:1;
unsigned int collectionNodeNumberOfItemsInSection:1;
unsigned int collectionNodeContextForSection:1;
unsigned int collectionNodeCanMoveItem:1;
unsigned int collectionNodeMoveItem:1;
// Whether this data source conforms to ASCollectionDataSourceInterop
unsigned int interop:1;
// Whether this interop data source returns YES from +dequeuesCellsForNodeBackedItems
unsigned int interopAlwaysDequeue:1;
// Whether this interop data source implements viewForSupplementaryElementOfKind:
unsigned int interopViewForSupplementaryElement:1;
} _asyncDataSourceFlags;
struct {
unsigned int constrainedSizeForSupplementaryNodeOfKindAtIndexPath:1;
unsigned int supplementaryNodesOfKindInSection:1;
unsigned int didChangeCollectionViewDataSource:1;
unsigned int didChangeCollectionViewDelegate:1;
} _layoutInspectorFlags;
BOOL _hasDataControllerLayoutDelegate;
}
@end
@implementation ASCollectionView
{
__weak id<ASCollectionDelegate> _asyncDelegate;
__weak id<ASCollectionDataSource> _asyncDataSource;
}
// Using _ASDisplayLayer ensures things like -layout are properly forwarded to ASCollectionNode.
+ (Class)layerClass
{
return [_ASDisplayLayer class];
}
#pragma mark -
#pragma mark Lifecycle.
- (instancetype)initWithCollectionViewLayout:(UICollectionViewLayout *)layout
{
return [self initWithFrame:CGRectZero collectionViewLayout:layout];
}
- (instancetype)initWithFrame:(CGRect)frame collectionViewLayout:(UICollectionViewLayout *)layout
{
return [self _initWithFrame:frame collectionViewLayout:layout layoutFacilitator:nil owningNode:nil eventLog:nil];
}
- (instancetype)_initWithFrame:(CGRect)frame collectionViewLayout:(UICollectionViewLayout *)layout layoutFacilitator:(id<ASCollectionViewLayoutFacilitatorProtocol>)layoutFacilitator owningNode:(ASCollectionNode *)owningNode eventLog:(ASEventLog *)eventLog
{
if (!(self = [super initWithFrame:frame collectionViewLayout:layout]))
return nil;
// Disable UICollectionView prefetching. Use super, because self disables this method.
// Experiments done by Instagram show that this option being YES (default)
// when unused causes a significant hit to scroll performance.
// https://github.com/Instagram/IGListKit/issues/318
if (AS_AVAILABLE_IOS_TVOS(10, 10)) {
super.prefetchingEnabled = NO;
}
_layoutController = [[ASCollectionViewLayoutController alloc] initWithCollectionView:self];
_rangeController = [[ASRangeController alloc] init];
_rangeController.dataSource = self;
_rangeController.delegate = self;
_rangeController.layoutController = _layoutController;
_dataController = [[ASDataController alloc] initWithDataSource:self node:owningNode eventLog:eventLog];
_dataController.delegate = _rangeController;
_batchContext = [[ASBatchContext alloc] init];
_leadingScreensForBatching = 2.0;
_lastBoundsSizeUsedForMeasuringNodes = self.bounds.size;
_layoutFacilitator = layoutFacilitator;
_proxyDelegate = [[ASCollectionViewProxy alloc] initWithTarget:nil interceptor:self];
super.delegate = (id<UICollectionViewDelegate>)_proxyDelegate;
_proxyDataSource = [[ASCollectionViewProxy alloc] initWithTarget:nil interceptor:self];
super.dataSource = (id<UICollectionViewDataSource>)_proxyDataSource;
_registeredSupplementaryKinds = [[NSMutableSet alloc] init];
_visibleElements = [[NSCountedSet alloc] init];
_cellsForVisibilityUpdates = [NSHashTable hashTableWithOptions:NSHashTableObjectPointerPersonality];
_cellsForLayoutUpdates = [NSHashTable hashTableWithOptions:NSHashTableObjectPointerPersonality];
self.backgroundColor = [UIColor whiteColor];
[self registerClass:[_ASCollectionViewCell class] forCellWithReuseIdentifier:kReuseIdentifier];
[self _configureCollectionViewLayout:layout];
return self;
}
- (void)dealloc
{
ASDisplayNodeAssertMainThread();
ASDisplayNodeCAssert(_batchUpdateCount == 0, @"ASCollectionView deallocated in the middle of a batch update.");
// Sometimes the UIKit classes can call back to their delegate even during deallocation, due to animation completion blocks etc.
_isDeallocating = YES;
if (!ASActivateExperimentalFeature(ASExperimentalCollectionTeardown)) {
[self setAsyncDelegate:nil];
[self setAsyncDataSource:nil];
}
// Data controller & range controller may own a ton of nodes, let's deallocate those off-main.
ASPerformBackgroundDeallocation(&_dataController);
ASPerformBackgroundDeallocation(&_rangeController);
}
#pragma mark -
#pragma mark Overrides.
/**
* This method is not available to be called by the public i.e.
* it should only be called by UICollectionView itself. UICollectionView
* does this e.g. during the first layout pass, or if you call -numberOfSections
* before its content is loaded.
*/
- (void)reloadData
{
[super reloadData];
// UICollectionView calls -reloadData during first layoutSubviews and when the data source changes.
// This fires off the first load of cell nodes.
if (_asyncDataSource != nil && !self.dataController.initialReloadDataHasBeenCalled) {
[self performBatchUpdates:^{
[_changeSet reloadData];
} completion:nil];
}
}
- (void)scrollToItemAtIndexPath:(NSIndexPath *)indexPath atScrollPosition:(UICollectionViewScrollPosition)scrollPosition animated:(BOOL)animated
{
if ([self validateIndexPath:indexPath]) {
[super scrollToItemAtIndexPath:indexPath atScrollPosition:scrollPosition animated:animated];
}
}
- (void)relayoutItems
{
[_dataController relayoutAllNodesWithInvalidationBlock:^{
[self.collectionViewLayout invalidateLayout];
[self invalidateFlowLayoutDelegateMetrics];
}];
}
- (BOOL)isProcessingUpdates
{
return [_dataController isProcessingUpdates];
}
- (void)onDidFinishProcessingUpdates:(void (^)())completion
{
[_dataController onDidFinishProcessingUpdates:completion];
}
- (void)waitUntilAllUpdatesAreCommitted
{
ASDisplayNodeAssertMainThread();
if (_batchUpdateCount > 0) {
// This assertion will be enabled soon.
// ASDisplayNodeFailAssert(@"Should not call %@ during batch update", NSStringFromSelector(_cmd));
return;
}
[_dataController waitUntilAllUpdatesAreProcessed];
}
- (BOOL)isSynchronized
{
return [_dataController isSynchronized];
}
- (void)onDidFinishSynchronizing:(void (^)())completion
{
[_dataController onDidFinishSynchronizing:completion];
}
- (void)setDataSource:(id<UICollectionViewDataSource>)dataSource
{
// UIKit can internally generate a call to this method upon changing the asyncDataSource; only assert for non-nil. We also allow this when we're doing interop.
ASDisplayNodeAssert(_asyncDelegateFlags.interop || dataSource == nil, @"ASCollectionView uses asyncDataSource, not UICollectionView's dataSource property.");
}
- (void)setDelegate:(id<UICollectionViewDelegate>)delegate
{
// Our UIScrollView superclass sets its delegate to nil on dealloc. Only assert if we get a non-nil value here. We also allow this when we're doing interop.
ASDisplayNodeAssert(_asyncDelegateFlags.interop || delegate == nil, @"ASCollectionView uses asyncDelegate, not UICollectionView's delegate property.");
}
- (void)proxyTargetHasDeallocated:(ASDelegateProxy *)proxy
{
if (proxy == _proxyDelegate) {
[self setAsyncDelegate:nil];
} else if (proxy == _proxyDataSource) {
[self setAsyncDataSource:nil];
}
}
- (id<ASCollectionDataSource>)asyncDataSource
{
return _asyncDataSource;
}
- (void)setAsyncDataSource:(id<ASCollectionDataSource>)asyncDataSource
{
// Changing super.dataSource will trigger a setNeedsLayout, so this must happen on the main thread.
ASDisplayNodeAssertMainThread();
// Note: It's common to check if the value hasn't changed and short-circuit but we aren't doing that here to handle
// the (common) case of nilling the asyncDataSource in the ViewController's dealloc. In this case our _asyncDataSource
// will return as nil (ARC magic) even though the _proxyDataSource still exists. It's really important to hold a strong
// reference to the old dataSource in this case because calls to ASCollectionViewProxy will start failing and cause crashes.
NS_VALID_UNTIL_END_OF_SCOPE id oldDataSource = super.dataSource;
if (asyncDataSource == nil) {
_asyncDataSource = nil;
_proxyDataSource = _isDeallocating ? nil : [[ASCollectionViewProxy alloc] initWithTarget:nil interceptor:self];
_asyncDataSourceFlags = {};
} else {
_asyncDataSource = asyncDataSource;
_proxyDataSource = [[ASCollectionViewProxy alloc] initWithTarget:_asyncDataSource interceptor:self];
_asyncDataSourceFlags.collectionViewNodeForItem = [_asyncDataSource respondsToSelector:@selector(collectionView:nodeForItemAtIndexPath:)];
_asyncDataSourceFlags.collectionViewNodeBlockForItem = [_asyncDataSource respondsToSelector:@selector(collectionView:nodeBlockForItemAtIndexPath:)];
_asyncDataSourceFlags.numberOfSectionsInCollectionView = [_asyncDataSource respondsToSelector:@selector(numberOfSectionsInCollectionView:)];
_asyncDataSourceFlags.collectionViewNumberOfItemsInSection = [_asyncDataSource respondsToSelector:@selector(collectionView:numberOfItemsInSection:)];
_asyncDataSourceFlags.collectionViewNodeForSupplementaryElement = [_asyncDataSource respondsToSelector:@selector(collectionView:nodeForSupplementaryElementOfKind:atIndexPath:)];
_asyncDataSourceFlags.collectionNodeNodeForItem = [_asyncDataSource respondsToSelector:@selector(collectionNode:nodeForItemAtIndexPath:)];
_asyncDataSourceFlags.collectionNodeNodeBlockForItem = [_asyncDataSource respondsToSelector:@selector(collectionNode:nodeBlockForItemAtIndexPath:)];
_asyncDataSourceFlags.numberOfSectionsInCollectionNode = [_asyncDataSource respondsToSelector:@selector(numberOfSectionsInCollectionNode:)];
_asyncDataSourceFlags.collectionNodeNumberOfItemsInSection = [_asyncDataSource respondsToSelector:@selector(collectionNode:numberOfItemsInSection:)];
_asyncDataSourceFlags.collectionNodeContextForSection = [_asyncDataSource respondsToSelector:@selector(collectionNode:contextForSection:)];
_asyncDataSourceFlags.collectionNodeNodeForSupplementaryElement = [_asyncDataSource respondsToSelector:@selector(collectionNode:nodeForSupplementaryElementOfKind:atIndexPath:)];
_asyncDataSourceFlags.collectionNodeNodeBlockForSupplementaryElement = [_asyncDataSource respondsToSelector:@selector(collectionNode:nodeBlockForSupplementaryElementOfKind:atIndexPath:)];
_asyncDataSourceFlags.collectionNodeSupplementaryElementKindsInSection = [_asyncDataSource respondsToSelector:@selector(collectionNode:supplementaryElementKindsInSection:)];
_asyncDataSourceFlags.nodeModelForItem = [_asyncDataSource respondsToSelector:@selector(collectionNode:nodeModelForItemAtIndexPath:)];
_asyncDataSourceFlags.collectionNodeCanMoveItem = [_asyncDataSource respondsToSelector:@selector(collectionNode:canMoveItemWithNode:)];
_asyncDataSourceFlags.collectionNodeMoveItem = [_asyncDataSource respondsToSelector:@selector(collectionNode:moveItemAtIndexPath:toIndexPath:)];
_asyncDataSourceFlags.interop = [_asyncDataSource conformsToProtocol:@protocol(ASCollectionDataSourceInterop)];
if (_asyncDataSourceFlags.interop) {
id<ASCollectionDataSourceInterop> interopDataSource = (id<ASCollectionDataSourceInterop>)_asyncDataSource;
_asyncDataSourceFlags.interopAlwaysDequeue = [[interopDataSource class] respondsToSelector:@selector(dequeuesCellsForNodeBackedItems)] && [[interopDataSource class] dequeuesCellsForNodeBackedItems];
_asyncDataSourceFlags.interopViewForSupplementaryElement = [interopDataSource respondsToSelector:@selector(collectionView:viewForSupplementaryElementOfKind:atIndexPath:)];
}
ASDisplayNodeAssert(_asyncDataSourceFlags.collectionNodeNumberOfItemsInSection || _asyncDataSourceFlags.collectionViewNumberOfItemsInSection, @"Data source must implement collectionNode:numberOfItemsInSection:");
ASDisplayNodeAssert(_asyncDataSourceFlags.collectionNodeNodeBlockForItem
|| _asyncDataSourceFlags.collectionNodeNodeForItem
|| _asyncDataSourceFlags.collectionViewNodeBlockForItem
|| _asyncDataSourceFlags.collectionViewNodeForItem, @"Data source must implement collectionNode:nodeBlockForItemAtIndexPath: or collectionNode:nodeForItemAtIndexPath:");
}
_dataController.validationErrorSource = asyncDataSource;
super.dataSource = (id<UICollectionViewDataSource>)_proxyDataSource;
//Cache results of layoutInspector to ensure flags are up to date if getter lazily loads a new one.
id<ASCollectionViewLayoutInspecting> layoutInspector = self.layoutInspector;
if (_layoutInspectorFlags.didChangeCollectionViewDataSource) {
[layoutInspector didChangeCollectionViewDataSource:asyncDataSource];
}
[self _asyncDelegateOrDataSourceDidChange];
}
- (id<ASCollectionDelegate>)asyncDelegate
{
return _asyncDelegate;
}
- (void)setAsyncDelegate:(id<ASCollectionDelegate>)asyncDelegate
{
// Changing super.delegate will trigger a setNeedsLayout, so this must happen on the main thread.
ASDisplayNodeAssertMainThread();
// Note: It's common to check if the value hasn't changed and short-circuit but we aren't doing that here to handle
// the (common) case of nilling the asyncDelegate in the ViewController's dealloc. In this case our _asyncDelegate
// will return as nil (ARC magic) even though the _proxyDataSource still exists. It's really important to hold a strong
// reference to the old delegate in this case because calls to ASCollectionViewProxy will start failing and cause crashes.
NS_VALID_UNTIL_END_OF_SCOPE id oldDelegate = super.delegate;
if (asyncDelegate == nil) {
_asyncDelegate = nil;
_proxyDelegate = _isDeallocating ? nil : [[ASCollectionViewProxy alloc] initWithTarget:nil interceptor:self];
_asyncDelegateFlags = {};
} else {
_asyncDelegate = asyncDelegate;
_proxyDelegate = [[ASCollectionViewProxy alloc] initWithTarget:_asyncDelegate interceptor:self];
_asyncDelegateFlags.scrollViewDidScroll = [_asyncDelegate respondsToSelector:@selector(scrollViewDidScroll:)];
_asyncDelegateFlags.scrollViewWillEndDragging = [_asyncDelegate respondsToSelector:@selector(scrollViewWillEndDragging:withVelocity:targetContentOffset:)];
_asyncDelegateFlags.scrollViewDidEndDecelerating = [_asyncDelegate respondsToSelector:@selector(scrollViewDidEndDecelerating:)];
_asyncDelegateFlags.scrollViewWillBeginDragging = [_asyncDelegate respondsToSelector:@selector(scrollViewWillBeginDragging:)];
_asyncDelegateFlags.scrollViewDidEndDragging = [_asyncDelegate respondsToSelector:@selector(scrollViewDidEndDragging:willDecelerate:)];
_asyncDelegateFlags.collectionViewWillDisplayNodeForItem = [_asyncDelegate respondsToSelector:@selector(collectionView:willDisplayNode:forItemAtIndexPath:)];
if (_asyncDelegateFlags.collectionViewWillDisplayNodeForItem == NO) {
_asyncDelegateFlags.collectionViewWillDisplayNodeForItemDeprecated = [_asyncDelegate respondsToSelector:@selector(collectionView:willDisplayNodeForItemAtIndexPath:)];
}
_asyncDelegateFlags.collectionViewDidEndDisplayingNodeForItem = [_asyncDelegate respondsToSelector:@selector(collectionView:didEndDisplayingNode:forItemAtIndexPath:)];
_asyncDelegateFlags.collectionViewWillBeginBatchFetch = [_asyncDelegate respondsToSelector:@selector(collectionView:willBeginBatchFetchWithContext:)];
_asyncDelegateFlags.shouldBatchFetchForCollectionView = [_asyncDelegate respondsToSelector:@selector(shouldBatchFetchForCollectionView:)];
_asyncDelegateFlags.collectionViewShouldSelectItem = [_asyncDelegate respondsToSelector:@selector(collectionView:shouldSelectItemAtIndexPath:)];
_asyncDelegateFlags.collectionViewDidSelectItem = [_asyncDelegate respondsToSelector:@selector(collectionView:didSelectItemAtIndexPath:)];
_asyncDelegateFlags.collectionViewShouldDeselectItem = [_asyncDelegate respondsToSelector:@selector(collectionView:shouldDeselectItemAtIndexPath:)];
_asyncDelegateFlags.collectionViewDidDeselectItem = [_asyncDelegate respondsToSelector:@selector(collectionView:didDeselectItemAtIndexPath:)];
_asyncDelegateFlags.collectionViewShouldHighlightItem = [_asyncDelegate respondsToSelector:@selector(collectionView:shouldHighlightItemAtIndexPath:)];
_asyncDelegateFlags.collectionViewDidHighlightItem = [_asyncDelegate respondsToSelector:@selector(collectionView:didHighlightItemAtIndexPath:)];
_asyncDelegateFlags.collectionViewDidUnhighlightItem = [_asyncDelegate respondsToSelector:@selector(collectionView:didUnhighlightItemAtIndexPath:)];
_asyncDelegateFlags.collectionViewShouldShowMenuForItem = [_asyncDelegate respondsToSelector:@selector(collectionView:shouldShowMenuForItemAtIndexPath:)];
_asyncDelegateFlags.collectionViewCanPerformActionForItem = [_asyncDelegate respondsToSelector:@selector(collectionView:canPerformAction:forItemAtIndexPath:withSender:)];
_asyncDelegateFlags.collectionViewPerformActionForItem = [_asyncDelegate respondsToSelector:@selector(collectionView:performAction:forItemAtIndexPath:withSender:)];
_asyncDelegateFlags.collectionNodeWillDisplayItem = [_asyncDelegate respondsToSelector:@selector(collectionNode:willDisplayItemWithNode:)];
_asyncDelegateFlags.collectionNodeDidEndDisplayingItem = [_asyncDelegate respondsToSelector:@selector(collectionNode:didEndDisplayingItemWithNode:)];
_asyncDelegateFlags.collectionNodeWillBeginBatchFetch = [_asyncDelegate respondsToSelector:@selector(collectionNode:willBeginBatchFetchWithContext:)];
_asyncDelegateFlags.shouldBatchFetchForCollectionNode = [_asyncDelegate respondsToSelector:@selector(shouldBatchFetchForCollectionNode:)];
_asyncDelegateFlags.collectionNodeShouldSelectItem = [_asyncDelegate respondsToSelector:@selector(collectionNode:shouldSelectItemAtIndexPath:)];
_asyncDelegateFlags.collectionNodeDidSelectItem = [_asyncDelegate respondsToSelector:@selector(collectionNode:didSelectItemAtIndexPath:)];
_asyncDelegateFlags.collectionNodeShouldDeselectItem = [_asyncDelegate respondsToSelector:@selector(collectionNode:shouldDeselectItemAtIndexPath:)];
_asyncDelegateFlags.collectionNodeDidDeselectItem = [_asyncDelegate respondsToSelector:@selector(collectionNode:didDeselectItemAtIndexPath:)];
_asyncDelegateFlags.collectionNodeShouldHighlightItem = [_asyncDelegate respondsToSelector:@selector(collectionNode:shouldHighlightItemAtIndexPath:)];
_asyncDelegateFlags.collectionNodeDidHighlightItem = [_asyncDelegate respondsToSelector:@selector(collectionNode:didHighlightItemAtIndexPath:)];
_asyncDelegateFlags.collectionNodeDidUnhighlightItem = [_asyncDelegate respondsToSelector:@selector(collectionNode:didUnhighlightItemAtIndexPath:)];
_asyncDelegateFlags.collectionNodeShouldShowMenuForItem = [_asyncDelegate respondsToSelector:@selector(collectionNode:shouldShowMenuForItemAtIndexPath:)];
_asyncDelegateFlags.collectionNodeCanPerformActionForItem = [_asyncDelegate respondsToSelector:@selector(collectionNode:canPerformAction:forItemAtIndexPath:sender:)];
_asyncDelegateFlags.collectionNodePerformActionForItem = [_asyncDelegate respondsToSelector:@selector(collectionNode:performAction:forItemAtIndexPath:sender:)];
_asyncDelegateFlags.collectionNodeWillDisplaySupplementaryElement = [_asyncDelegate respondsToSelector:@selector(collectionNode:willDisplaySupplementaryElementWithNode:)];
_asyncDelegateFlags.collectionNodeDidEndDisplayingSupplementaryElement = [_asyncDelegate respondsToSelector:@selector(collectionNode:didEndDisplayingSupplementaryElementWithNode:)];
_asyncDelegateFlags.interop = [_asyncDelegate conformsToProtocol:@protocol(ASCollectionDelegateInterop)];
if (_asyncDelegateFlags.interop) {
id<ASCollectionDelegateInterop> interopDelegate = (id<ASCollectionDelegateInterop>)_asyncDelegate;
_asyncDelegateFlags.interopWillDisplayCell = [interopDelegate respondsToSelector:@selector(collectionView:willDisplayCell:forItemAtIndexPath:)];
_asyncDelegateFlags.interopDidEndDisplayingCell = [interopDelegate respondsToSelector:@selector(collectionView:didEndDisplayingCell:forItemAtIndexPath:)];
_asyncDelegateFlags.interopWillDisplaySupplementaryView = [interopDelegate respondsToSelector:@selector(collectionView:willDisplaySupplementaryView:forElementKind:atIndexPath:)];
_asyncDelegateFlags.interopdidEndDisplayingSupplementaryView = [interopDelegate respondsToSelector:@selector(collectionView:didEndDisplayingSupplementaryView:forElementOfKind:atIndexPath:)];
}
}
super.delegate = (id<UICollectionViewDelegate>)_proxyDelegate;
//Cache results of layoutInspector to ensure flags are up to date if getter lazily loads a new one.
id<ASCollectionViewLayoutInspecting> layoutInspector = self.layoutInspector;
if (_layoutInspectorFlags.didChangeCollectionViewDelegate) {
[layoutInspector didChangeCollectionViewDelegate:asyncDelegate];
}
[self _asyncDelegateOrDataSourceDidChange];
}
- (void)_asyncDelegateOrDataSourceDidChange
{
ASDisplayNodeAssertMainThread();
if (_asyncDataSource == nil && _asyncDelegate == nil) {
[_dataController clearData];
}
}
- (void)setCollectionViewLayout:(nonnull UICollectionViewLayout *)collectionViewLayout
{
ASDisplayNodeAssertMainThread();
[super setCollectionViewLayout:collectionViewLayout];
[self _configureCollectionViewLayout:collectionViewLayout];
// Trigger recreation of layout inspector with new collection view layout
if (_layoutInspector != nil) {
_layoutInspector = nil;
[self layoutInspector];
}
}
- (id<ASCollectionViewLayoutInspecting>)layoutInspector
{
if (_layoutInspector == nil) {
UICollectionViewLayout *layout = self.collectionViewLayout;
if (layout == nil) {
// Layout hasn't been set yet, we're still init'ing
return nil;
}
_defaultLayoutInspector = [layout asdk_layoutInspector];
ASDisplayNodeAssertNotNil(_defaultLayoutInspector, @"You must not return nil from -asdk_layoutInspector. Return [super asdk_layoutInspector] if you have to! Layout: %@", layout);
// Explicitly call the setter to wire up the _layoutInspectorFlags
self.layoutInspector = _defaultLayoutInspector;
}
return _layoutInspector;
}
- (void)setLayoutInspector:(id<ASCollectionViewLayoutInspecting>)layoutInspector
{
_layoutInspector = layoutInspector;
_layoutInspectorFlags.constrainedSizeForSupplementaryNodeOfKindAtIndexPath = [_layoutInspector respondsToSelector:@selector(collectionView:constrainedSizeForSupplementaryNodeOfKind:atIndexPath:)];
_layoutInspectorFlags.supplementaryNodesOfKindInSection = [_layoutInspector respondsToSelector:@selector(collectionView:supplementaryNodesOfKind:inSection:)];
_layoutInspectorFlags.didChangeCollectionViewDataSource = [_layoutInspector respondsToSelector:@selector(didChangeCollectionViewDataSource:)];
_layoutInspectorFlags.didChangeCollectionViewDelegate = [_layoutInspector respondsToSelector:@selector(didChangeCollectionViewDelegate:)];
if (_layoutInspectorFlags.didChangeCollectionViewDataSource) {
[_layoutInspector didChangeCollectionViewDataSource:self.asyncDataSource];
}
if (_layoutInspectorFlags.didChangeCollectionViewDelegate) {
[_layoutInspector didChangeCollectionViewDelegate:self.asyncDelegate];
}
}
- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeType:(ASLayoutRangeType)rangeType
{
[_rangeController setTuningParameters:tuningParameters forRangeMode:ASLayoutRangeModeFull rangeType:rangeType];
}
- (ASRangeTuningParameters)tuningParametersForRangeType:(ASLayoutRangeType)rangeType
{
return [_rangeController tuningParametersForRangeMode:ASLayoutRangeModeFull rangeType:rangeType];
}
- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeMode:(ASLayoutRangeMode)rangeMode rangeType:(ASLayoutRangeType)rangeType
{
[_rangeController setTuningParameters:tuningParameters forRangeMode:rangeMode rangeType:rangeType];
}
- (ASRangeTuningParameters)tuningParametersForRangeMode:(ASLayoutRangeMode)rangeMode rangeType:(ASLayoutRangeType)rangeType
{
return [_rangeController tuningParametersForRangeMode:rangeMode rangeType:rangeType];
}
- (void)setZeroContentInsets:(BOOL)zeroContentInsets
{
_zeroContentInsets = zeroContentInsets;
}
- (BOOL)zeroContentInsets
{
return _zeroContentInsets;
}
/// Uses latest size range from data source and -layoutThatFits:.
- (CGSize)sizeForElement:(ASCollectionElement *)element
{
ASDisplayNodeAssertMainThread();
if (element == nil) {
return CGSizeZero;
}
ASCellNode *node = element.node;
ASDisplayNodeAssertNotNil(node, @"Node must not be nil!");
BOOL useUIKitCell = node.shouldUseUIKitCell;
if (useUIKitCell) {
ASWrapperCellNode *wrapperNode = (ASWrapperCellNode *)node;
if (wrapperNode.sizeForItemBlock) {
return wrapperNode.sizeForItemBlock(wrapperNode, element.constrainedSize.max);
} else {
// In this case, we should use the exact value that was stashed earlier by calling sizeForItem:, referenceSizeFor*, etc.
// Although the node would use the preferredSize in layoutThatFits, we can skip this because there's no constrainedSize.
return wrapperNode.style.preferredSize;
}
} else {
return [node layoutThatFits:element.constrainedSize].size;
}
}
- (CGSize)calculatedSizeForNodeAtIndexPath:(NSIndexPath *)indexPath
{
ASDisplayNodeAssertMainThread();
ASCollectionElement *e = [_dataController.visibleMap elementForItemAtIndexPath:indexPath];
return [self sizeForElement:e];
}
- (ASCellNode *)nodeForItemAtIndexPath:(NSIndexPath *)indexPath
{
return [_dataController.visibleMap elementForItemAtIndexPath:indexPath].node;
}
- (NSIndexPath *)convertIndexPathFromCollectionNode:(NSIndexPath *)indexPath waitingIfNeeded:(BOOL)wait
{
if (indexPath == nil) {
return nil;
}
NSIndexPath *viewIndexPath = [_dataController.visibleMap convertIndexPath:indexPath fromMap:_dataController.pendingMap];
if (viewIndexPath == nil && wait) {
[self waitUntilAllUpdatesAreCommitted];
return [self convertIndexPathFromCollectionNode:indexPath waitingIfNeeded:NO];
}
return viewIndexPath;
}
/**
* Asserts that the index path is a valid view-index-path, and returns it if so, nil otherwise.
*/
- (nullable NSIndexPath *)validateIndexPath:(nullable NSIndexPath *)indexPath
{
if (indexPath == nil) {
return nil;
}
NSInteger section = indexPath.section;
if (section >= self.numberOfSections) {
ASDisplayNodeFailAssert(@"Collection view index path has invalid section %lu, section count = %lu", (unsigned long)section, (unsigned long)self.numberOfSections);
return nil;
}
NSInteger item = indexPath.item;
// item == NSNotFound means e.g. "scroll to this section" and is acceptable
if (item != NSNotFound && item >= [self numberOfItemsInSection:section]) {
ASDisplayNodeFailAssert(@"Collection view index path has invalid item %lu in section %lu, item count = %lu", (unsigned long)indexPath.item, (unsigned long)section, (unsigned long)[self numberOfItemsInSection:section]);
return nil;
}
return indexPath;
}
- (NSIndexPath *)convertIndexPathToCollectionNode:(NSIndexPath *)indexPath
{
if ([self validateIndexPath:indexPath] == nil) {
return nil;
}
return [_dataController.pendingMap convertIndexPath:indexPath fromMap:_dataController.visibleMap];
}
- (NSArray<NSIndexPath *> *)convertIndexPathsToCollectionNode:(NSArray<NSIndexPath *> *)indexPaths
{
return ASArrayByFlatMapping(indexPaths, NSIndexPath *viewIndexPath, [self convertIndexPathToCollectionNode:viewIndexPath]);
}
- (ASCellNode *)supplementaryNodeForElementKind:(NSString *)elementKind atIndexPath:(NSIndexPath *)indexPath
{
return [_dataController.visibleMap supplementaryElementOfKind:elementKind atIndexPath:indexPath].node;
}
- (NSIndexPath *)indexPathForNode:(ASCellNode *)cellNode
{
return [_dataController.visibleMap indexPathForElement:cellNode.collectionElement];
}
- (NSArray *)visibleNodes
{
NSArray *indexPaths = [self indexPathsForVisibleItems];
NSMutableArray *visibleNodes = [[NSMutableArray alloc] init];
for (NSIndexPath *indexPath in indexPaths) {
ASCellNode *node = [self nodeForItemAtIndexPath:indexPath];
if (node) {
// It is possible for UICollectionView to return indexPaths before the node is completed.
[visibleNodes addObject:node];
}
}
return visibleNodes;
}
- (BOOL)usesSynchronousDataLoading
{
return self.dataController.usesSynchronousDataLoading;
}
- (void)setUsesSynchronousDataLoading:(BOOL)usesSynchronousDataLoading
{
self.dataController.usesSynchronousDataLoading = usesSynchronousDataLoading;
}
- (void)invalidateFlowLayoutDelegateMetrics {
for (ASCollectionElement *element in self.dataController.pendingMap) {
// This may be either a Supplementary or Item type element.
// For UIKit passthrough cells of either type, re-fetch their sizes from the standard UIKit delegate methods.
ASCellNode *node = element.node;
if (node.shouldUseUIKitCell) {
ASWrapperCellNode *wrapperNode = (ASWrapperCellNode *)node;
if (wrapperNode.sizeForItemBlock) {
continue;
}
NSIndexPath *indexPath = [_dataController.pendingMap indexPathForElement:element];
NSString *kind = [element supplementaryElementKind];
CGSize previousSize = node.style.preferredSize;
CGSize size = [self _sizeForUIKitCellWithKind:kind atIndexPath:indexPath];
if (!CGSizeEqualToSize(previousSize, size)) {
node.style.preferredSize = size;
[node invalidateCalculatedLayout];
}
}
}
}
#pragma mark Internal
- (void)_configureCollectionViewLayout:(nonnull UICollectionViewLayout *)layout
{
_hasDataControllerLayoutDelegate = [layout conformsToProtocol:@protocol(ASDataControllerLayoutDelegate)];
if (_hasDataControllerLayoutDelegate) {
_dataController.layoutDelegate = (id<ASDataControllerLayoutDelegate>)layout;
}
}
/**
This method is called only for UIKit Passthrough cells - either regular Items or Supplementary elements.
It checks if the delegate implements the UICollectionViewFlowLayout methods that provide sizes, and if not,
uses the default values set on the flow layout. If a flow layout is not in use, UICollectionView Passthrough
cells must be sized by logic in the Layout object, and Texture does not participate in these paths.
*/
- (CGSize)_sizeForUIKitCellWithKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
{
CGSize size = CGSizeZero;
UICollectionViewLayout *l = self.collectionViewLayout;
if (kind == nil) {
ASDisplayNodeAssert(_asyncDataSourceFlags.interop, @"This code should not be called except for UIKit passthrough compatibility");
SEL sizeForItem = @selector(collectionView:layout:sizeForItemAtIndexPath:);
if (indexPath && [_asyncDelegate respondsToSelector:sizeForItem]) {
size = [(id)_asyncDelegate collectionView:self layout:l sizeForItemAtIndexPath:indexPath];
} else {
size = ASFlowLayoutDefault(l, itemSize, CGSizeZero);
}
} else if ([kind isEqualToString:UICollectionElementKindSectionHeader]) {
ASDisplayNodeAssert(_asyncDataSourceFlags.interopViewForSupplementaryElement, @"This code should not be called except for UIKit passthrough compatibility");
SEL sizeForHeader = @selector(collectionView:layout:referenceSizeForHeaderInSection:);
if (indexPath && [_asyncDelegate respondsToSelector:sizeForHeader]) {
size = [(id)_asyncDelegate collectionView:self layout:l referenceSizeForHeaderInSection:indexPath.section];
} else {
size = ASFlowLayoutDefault(l, headerReferenceSize, CGSizeZero);
}
} else if ([kind isEqualToString:UICollectionElementKindSectionFooter]) {
ASDisplayNodeAssert(_asyncDataSourceFlags.interopViewForSupplementaryElement, @"This code should not be called except for UIKit passthrough compatibility");
SEL sizeForFooter = @selector(collectionView:layout:referenceSizeForFooterInSection:);
if (indexPath && [_asyncDelegate respondsToSelector:sizeForFooter]) {
size = [(id)_asyncDelegate collectionView:self layout:l referenceSizeForFooterInSection:indexPath.section];
} else {
size = ASFlowLayoutDefault(l, footerReferenceSize, CGSizeZero);
}
}
return size;
}
/**
Performing nested batch updates with super (e.g. resizing a cell node & updating collection view during same frame)
can cause super to throw data integrity exceptions because it checks the data source counts before
the update is complete.
Always call [self _superPerform:] rather than [super performBatch:] so that we can keep our `superPerformingBatchUpdates` flag updated.
*/
- (void)_superPerformBatchUpdates:(void(^)())updates completion:(void(^)(BOOL finished))completion
{
ASDisplayNodeAssertMainThread();
_superBatchUpdateCount++;
[super performBatchUpdates:updates completion:completion];
_superBatchUpdateCount--;
}
#pragma mark Assertions.
- (ASDataController *)dataController
{
return _dataController;
}
- (void)beginUpdates
{
ASDisplayNodeAssertMainThread();
// _changeSet must be available during batch update
ASDisplayNodeAssertTrue((_batchUpdateCount > 0) == (_changeSet != nil));
if (_batchUpdateCount == 0) {
_changeSet = [[_ASHierarchyChangeSet alloc] initWithOldData:[_dataController itemCountsFromDataSource]];
_changeSet.rootActivity = as_activity_create("Perform async collection update", AS_ACTIVITY_CURRENT, OS_ACTIVITY_FLAG_DEFAULT);
_changeSet.submitActivity = as_activity_create("Submit changes for collection update", _changeSet.rootActivity, OS_ACTIVITY_FLAG_DEFAULT);
}
_batchUpdateCount++;
}
- (void)endUpdatesAnimated:(BOOL)animated completion:(nullable void (^)(BOOL))completion
{
ASDisplayNodeAssertMainThread();
ASDisplayNodeAssertNotNil(_changeSet, @"_changeSet must be available when batch update ends");
_batchUpdateCount--;
// Prevent calling endUpdatesAnimated:completion: in an unbalanced way
NSAssert(_batchUpdateCount >= 0, @"endUpdatesAnimated:completion: called without having a balanced beginUpdates call");
[_changeSet addCompletionHandler:completion];
if (_batchUpdateCount == 0) {
_ASHierarchyChangeSet *changeSet = _changeSet;
// Nil out _changeSet before forwarding to _dataController to allow the change set to cause subsequent batch updates on the same run loop
_changeSet = nil;
changeSet.animated = animated;
[_dataController updateWithChangeSet:changeSet];
}
}
- (void)performBatchAnimated:(BOOL)animated updates:(void (^)())updates completion:(void (^)(BOOL))completion
{
ASDisplayNodeAssertMainThread();
[self beginUpdates];
as_activity_scope(_changeSet.rootActivity);
{
// Only include client code in the submit activity, the rest just lives in the root activity.
as_activity_scope(_changeSet.submitActivity);
if (updates) {
updates();
}
}
[self endUpdatesAnimated:animated completion:completion];
}
- (void)performBatchUpdates:(void (^)())updates completion:(void (^)(BOOL))completion
{
// We capture the current state of whether animations are enabled if they don't provide us with one.
[self performBatchAnimated:[UIView areAnimationsEnabled] updates:updates completion:completion];
}
- (void)registerSupplementaryNodeOfKind:(NSString *)elementKind
{
ASDisplayNodeAssert(elementKind != nil, @"A kind is needed for supplementary node registration");
[_registeredSupplementaryKinds addObject:elementKind];
[self registerClass:[_ASCollectionReusableView class] forSupplementaryViewOfKind:elementKind withReuseIdentifier:kReuseIdentifier];
}
- (void)insertSections:(NSIndexSet *)sections
{
ASDisplayNodeAssertMainThread();
if (sections.count == 0) { return; }
[self performBatchUpdates:^{
[_changeSet insertSections:sections animationOptions:kASCollectionViewAnimationNone];
} completion:nil];
}
- (void)deleteSections:(NSIndexSet *)sections
{
ASDisplayNodeAssertMainThread();
if (sections.count == 0) { return; }
[self performBatchUpdates:^{
[_changeSet deleteSections:sections animationOptions:kASCollectionViewAnimationNone];
} completion:nil];
}
- (void)reloadSections:(NSIndexSet *)sections
{
ASDisplayNodeAssertMainThread();
if (sections.count == 0) { return; }
[self performBatchUpdates:^{
[_changeSet reloadSections:sections animationOptions:kASCollectionViewAnimationNone];
} completion:nil];
}
- (void)moveSection:(NSInteger)section toSection:(NSInteger)newSection
{
ASDisplayNodeAssertMainThread();
[self performBatchUpdates:^{
[_changeSet moveSection:section toSection:newSection animationOptions:kASCollectionViewAnimationNone];
} completion:nil];
}
- (id<ASSectionContext>)contextForSection:(NSInteger)section
{
ASDisplayNodeAssertMainThread();
return [_dataController.visibleMap contextForSection:section];
}
- (void)insertItemsAtIndexPaths:(NSArray *)indexPaths
{
ASDisplayNodeAssertMainThread();
if (indexPaths.count == 0) { return; }
[self performBatchUpdates:^{
[_changeSet insertItems:indexPaths animationOptions:kASCollectionViewAnimationNone];
} completion:nil];