Revert "[ASTextNode] Fix text node truncation (#1863)"

This reverts commit 6238e5e.

We will re-apply this change, but there are some early signs of performance impacts that need to be investigated.

Author: appleguy

AsyncDisplayKit/TextKit/ASTextKitContext.h

@@ -10,8 +10,6 @@
 
 #import <UIKit/UIKit.h>
 
-typedef NSTextStorage *(^ASTextKitContextTextStorageCreationBlock)(NSAttributedString *attributedString);
-
 /**
  A threadsafe container for the TextKit components that ASTextKit uses to lay out and truncate its text.
 
@@ -32,19 +30,10 @@ typedef NSTextStorage *(^ASTextKitContextTextStorageCreationBlock)(NSAttributedS
                          constrainedSize:(CGSize)constrainedSize
               layoutManagerCreationBlock:(NSLayoutManager * (^)(void))layoutCreationBlock
                    layoutManagerDelegate:(id<NSLayoutManagerDelegate>)layoutManagerDelegate
-                textStorageCreationBlock:(ASTextKitContextTextStorageCreationBlock)textStorageCreationBlock;
+                textStorageCreationBlock:(NSTextStorage * (^)(NSAttributedString *attributedString))textStorageCreationBlock;
 
-/**
- Set the constrained size for the text context.
- */
 @property (nonatomic, assign, readwrite) CGSize constrainedSize;
 
-/**
- Resets the text storage to the original value in case it was truncated before. This method is called within
- a locked context.
- */
-- (void)resetTextStorage;
-
 /**
  All operations on TextKit values MUST occur within this locked context.  Simultaneous access (even non-mutative) to
  TextKit components may cause crashes.

AsyncDisplayKit/TextKit/ASTextKitContext.mm

@@ -21,12 +21,8 @@ @implementation ASTextKitContext
   NSLayoutManager *_layoutManager;
   NSTextStorage *_textStorage;
   NSTextContainer *_textContainer;
-  
-  NSAttributedString *_attributedString;
 }
 
-#pragma mark - Lifecycle
-
 - (instancetype)initWithAttributedString:(NSAttributedString *)attributedString
                            lineBreakMode:(NSLineBreakMode)lineBreakMode
                     maximumNumberOfLines:(NSUInteger)maximumNumberOfLines
@@ -41,23 +37,16 @@ - (instancetype)initWithAttributedString:(NSAttributedString *)attributedString
     // Concurrently initialising TextKit components crashes (rdar://18448377) so we use a global lock.
     static std::mutex __static_mutex;
     std::lock_guard<std::mutex> l(__static_mutex);
-    
-    _attributedString = [attributedString copy];
-    
     // Create the TextKit component stack with our default configuration.
     if (textStorageCreationBlock) {
       _textStorage = textStorageCreationBlock(attributedString);
     } else {
-      _textStorage = [[NSTextStorage alloc] init];
-      [self _resetTextStorage];
+      _textStorage = (attributedString ? [[NSTextStorage alloc] initWithAttributedString:attributedString] : [[NSTextStorage alloc] init]);
     }
-    
-    
     _layoutManager = layoutCreationBlock ? layoutCreationBlock() : [[ASLayoutManager alloc] init];
     _layoutManager.usesFontLeading = NO;
     _layoutManager.delegate = layoutManagerDelegate;
     [_textStorage addLayoutManager:_layoutManager];
-
     _textContainer = [[NSTextContainer alloc] initWithSize:constrainedSize];
     // We want the text laid out up to the very edges of the container.
     _textContainer.lineFragmentPadding = 0;
@@ -69,21 +58,6 @@ - (instancetype)initWithAttributedString:(NSAttributedString *)attributedString
   return self;
 }
 
-#pragma mark - Text Storage
-
-- (void)resetTextStorage
-{
-  std::lock_guard<std::mutex> l(_textKitMutex);
-  [self _resetTextStorage];
-}
-
-- (void)_resetTextStorage
-{
-  [_textStorage setAttributedString:_attributedString];
-}
-
-#pragma mark - Setter / Getter
-
 - (CGSize)constrainedSize
 {
   std::lock_guard<std::mutex> l(_textKitMutex);
@@ -96,8 +70,6 @@ - (void)setConstrainedSize:(CGSize)constrainedSize
   _textContainer.size = constrainedSize;
 }
 
-#pragma mark - Locking
-
 - (void)performBlockWithLockedTextKitComponents:(void (^)(NSLayoutManager *,
                                                           NSTextStorage *,
                                                           NSTextContainer *))block

AsyncDisplayKit/TextKit/ASTextKitRenderer.mm

@@ -128,12 +128,8 @@ - (void)setConstrainedSize:(CGSize)constrainedSize
       // If we're updating an existing context, make sure to use the same inset logic used during initialization.
       // This codepath allows us to reuse the
       CGSize shadowConstrainedSize = [[self shadower] insetSizeWithConstrainedSize:constrainedSize];
-      if (_context) {
-        _context.constrainedSize = shadowConstrainedSize;
-      }
-      if (_fontSizeAdjuster) {
-        _fontSizeAdjuster.constrainedSize = shadowConstrainedSize;
-      }
+      if (_context) _context.constrainedSize = shadowConstrainedSize;
+      if (_fontSizeAdjuster) _fontSizeAdjuster.constrainedSize = shadowConstrainedSize;
     }
   }
 }

AsyncDisplayKit/TextKit/ASTextKitTailTruncater.mm

@@ -150,14 +150,9 @@ - (NSUInteger)_findTruncationInsertionPointAtOrBeforeCharacterIndex:(NSUInteger)
 
 - (void)truncate
 {
-  // Reset the text storage to start always with the full string
-  [_context resetTextStorage];
-
-  // Start truncation
   [_context performBlockWithLockedTextKitComponents:^(NSLayoutManager *layoutManager, NSTextStorage *textStorage, NSTextContainer *textContainer) {
-    
     NSUInteger originalStringLength = textStorage.length;
-    
+
     [layoutManager ensureLayoutForTextContainer:textContainer];
 
     NSRange visibleGlyphRange = [layoutManager glyphRangeForBoundingRect:{ .size = textContainer.size }

AsyncDisplayKitTests/ASTextNodeTests.m

@@ -125,7 +125,7 @@ - (void)testRecalculationOfSizeIsSameAsOriginallyCalculatedSize
   for (NSInteger i = 10; i < 500; i += 50) {
     CGSize constrainedSize = CGSizeMake(i, i);
     CGSize calculatedSize = [_textNode measure:constrainedSize];
-    CGSize recalculatedSize = [_textNode measure:constrainedSize];
+    CGSize recalculatedSize = [_textNode measure:calculatedSize];
 
     XCTAssertTrue(CGSizeEqualToSizeWithIn(calculatedSize, recalculatedSize, 4.0), @"Recalculated size %@ should be same as original size %@", NSStringFromCGSize(recalculatedSize), NSStringFromCGSize(calculatedSize));
   }
@@ -136,7 +136,7 @@ - (void)testRecalculationOfSizeIsSameAsOriginallyCalculatedFloatingPointSize
   for (CGFloat i = 10; i < 500; i *= 1.3) {
     CGSize constrainedSize = CGSizeMake(i, i);
     CGSize calculatedSize = [_textNode measure:constrainedSize];
-    CGSize recalculatedSize = [_textNode measure:constrainedSize];
+    CGSize recalculatedSize = [_textNode measure:calculatedSize];
 
     XCTAssertTrue(CGSizeEqualToSizeWithIn(calculatedSize, recalculatedSize, 11.0), @"Recalculated size %@ should be same as original size %@", NSStringFromCGSize(recalculatedSize), NSStringFromCGSize(calculatedSize));
   }