[ASTextKitComponents] Temporary components can be deallocated off main

TextureGroup · Oct 10, 2017 · 1ccb858 · 1ccb858
1 parent 4dbb644
commit 1ccb858
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Showing 2 changed files with 17 additions and 5 deletions.
diff --git a/Source/TextKit/ASTextKitComponents.h b/Source/TextKit/ASTextKitComponents.h
@@ -59,7 +59,7 @@ AS_SUBCLASSING_RESTRICTED
 @property (nonatomic, strong, readonly) NSTextStorage *textStorage;
 @property (nonatomic, strong, readonly) NSTextContainer *textContainer;
 @property (nonatomic, strong, readonly) NSLayoutManager *layoutManager;
-@property (nullable, nonatomic, strong) UITextView *textView;
+@property (nonatomic, strong, nullable) UITextView *textView;
 
 @end
 

diff --git a/Source/TextKit/ASTextKitComponents.mm b/Source/TextKit/ASTextKitComponents.mm
@@ -27,6 +27,9 @@ @interface ASTextKitComponents ()
 @property (nonatomic, strong, readwrite) NSTextContainer *textContainer;
 @property (nonatomic, strong, readwrite) NSLayoutManager *layoutManager;
 
+// Indicates whether or not this object must be deallocated on main thread. Defaults to YES.
+@property (nonatomic, assign) BOOL requiresMainThreadDeallocation;
+
 @end
 
 @implementation ASTextKitComponents
@@ -58,17 +61,22 @@ + (instancetype)componentsWithTextStorage:(NSTextStorage *)textStorage
   components.textContainer.lineFragmentPadding = 0.0; // We want the text laid out up to the very edges of the text-view.
   [components.layoutManager addTextContainer:components.textContainer];
 
+  components.requiresMainThreadDeallocation = YES;
+
   return components;
 }
 
 #pragma mark - Lifecycle
 
 - (void)dealloc
 {
-  ASDisplayNodeAssertMainThread();
-
-  // Nil out all delegate to prevent crash
-  _textView.delegate = nil;
+  if (_requiresMainThreadDeallocation) {
+    ASDisplayNodeAssertMainThread();
+  }
+  // Nil out all delegates to prevent crash
+  if (_textView) {
+    _textView.delegate = nil;
+  }
   _layoutManager.delegate = nil;
 }
 
@@ -82,6 +90,8 @@ - (CGSize)sizeForConstrainedWidth:(CGFloat)constrainedWidth
   // Otherwise, we create a temporary stack to size for `constrainedWidth`.
   if (CGRectGetWidth(components.textView.bounds) != constrainedWidth) {
     components = [ASTextKitComponents componentsWithAttributedSeedString:components.textStorage textContainerSize:CGSizeMake(constrainedWidth, CGFLOAT_MAX)];
+    // The temporary stack can be deallocated off main
+    components.requiresMainThreadDeallocation = NO;
   }
 
   // Force glyph generation and layout, which may not have happened yet (and isn't triggered by -usedRectForTextContainer:).
@@ -102,6 +112,8 @@ - (CGSize)sizeForConstrainedWidth:(CGFloat)constrainedWidth
 
   // Always use temporary stack in case of threading issues
   components = [ASTextKitComponents componentsWithAttributedSeedString:components.textStorage textContainerSize:CGSizeMake(constrainedWidth, CGFLOAT_MAX)];
+  // The temporary stack can be deallocated off main
+  components.requiresMainThreadDeallocation = NO;
 
   // Force glyph generation and layout, which may not have happened yet (and isn't triggered by - usedRectForTextContainer:).
   [components.layoutManager ensureLayoutForTextContainer:components.textContainer];