mirror of
https://github.com/Swiftgram/Telegram-iOS.git
synced 2025-12-15 18:59:54 +00:00
75 lines
4.3 KiB
Plaintext
75 lines
4.3 KiB
Plaintext
/* 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 root directory of this source tree. An additional grant
|
|
* of patent rights can be found in the PATENTS file in the same directory.
|
|
*/
|
|
|
|
#import "ASRangeHandlerRender.h"
|
|
|
|
#import "ASDisplayNode.h"
|
|
#import "ASDisplayNode+Subclasses.h"
|
|
#import "ASDisplayNode+FrameworkPrivate.h"
|
|
#import "ASDisplayNode+Beta.h"
|
|
|
|
@interface ASRangeHandlerRender ()
|
|
@property (nonatomic,readonly) UIWindow *workingWindow;
|
|
@end
|
|
|
|
@implementation ASRangeHandlerRender
|
|
|
|
- (void)node:(ASDisplayNode *)node enteredRangeOfType:(ASLayoutRangeType)rangeType
|
|
{
|
|
ASDisplayNodeAssertMainThread();
|
|
ASDisplayNodeAssert(rangeType == ASLayoutRangeTypeDisplay, @"Render delegate should not handle other ranges");
|
|
|
|
// If a node had previously been onscreen but now is only in the working range,
|
|
// ensure its view is not orphaned in a UITableViewCell in the reuse pool.
|
|
if (![node isLayerBacked] && node.view.superview) {
|
|
[node.view removeFromSuperview];
|
|
}
|
|
|
|
// The node un-suspends display.
|
|
[node enterInterfaceState:ASInterfaceStateDisplay];
|
|
|
|
|
|
// ASDisplayNodeAssert(![ASDisplayNode shouldUseNewRenderingRange], @"It should no longer be possible to reach this point with the new display range enabled");
|
|
[node recursivelyEnsureDisplaySynchronously:NO];
|
|
}
|
|
|
|
- (void)node:(ASDisplayNode *)node exitedRangeOfType:(ASLayoutRangeType)rangeType
|
|
{
|
|
ASDisplayNodeAssertMainThread();
|
|
ASDisplayNodeAssert(rangeType == ASLayoutRangeTypeDisplay, @"Render delegate should not handle other ranges");
|
|
|
|
// This code is tricky. There are several possible states a node can be in when it reaches this point.
|
|
// 1. Layer-backed vs view-backed nodes. AS of this writing, only ASCellNodes arrive here, which are always view-backed —
|
|
// but we maintain correctness for all ASDisplayNodes, including layer-backed ones.
|
|
// (Note: it would not make sense to pass in a subnode of a rasterized node here, so that is unsupported).
|
|
// 2. The node's layer may have been added to the workingWindow previously, or it may have never been added, such as if rangeTuningParameter's leading value is 0.
|
|
// 3. The node's layer may not be present in the workingWindow, even if it was previously added.
|
|
// This is a common case, as once the node is added to an active cell contentsView (e.g. visible), it is automatically removed from the workingWindow.
|
|
// The system does this when addSublayer is called, even if removeFromSuperlayer is never explicitly called.
|
|
// 4. Lastly and most unusually, it is possible for a node to be offscreen, completely outside the heirarchy, and yet considered within the working range.
|
|
// This happens if the UITableViewCell is reused after scrolling offscreen. Because the node has already been given the opportunity to display, we do not
|
|
// proactively re-host it within the workingWindow (improving efficiency). Some time later, it may fall outside the working range, in which case calling
|
|
// -recursivelyClearContents is critical. If the user scrolls back and it is re-hosted in a UITableViewCell, the content will still exist as it is not cleared
|
|
// by simply being removed from the cell. The code that usually triggers this condition is the -removeFromSuperview in -[ASRangeController configureContentView:forCellNode:].
|
|
// Condition #4 is suboptimal in some cases, as it is conceivable that memory warnings could trigger clearing content that is inside the working range. However, enforcing the
|
|
// preservation of this content could result in the app being killed, which is not likely preferable over briefly seeing placeholders in the event the user scrolls backwards.
|
|
// Nonetheless, future changes to the implementation will likely eliminate this behavior to simplify debugging and extensibility of working range functionality.
|
|
|
|
// The node calls clearCurrentContents and suspends display
|
|
[node exitInterfaceState:ASInterfaceStateDisplay];
|
|
|
|
// ASDisplayNodeAssert(![ASDisplayNode shouldUseNewRenderingRange], @"It should no longer be possible to reach this point with the new display range enabled");
|
|
if (![node isLayerBacked]) {
|
|
[node.view removeFromSuperview];
|
|
} else {
|
|
[node.layer removeFromSuperlayer];
|
|
}
|
|
}
|
|
|
|
@end
|