Invalidate NSTextStorage on AttributedString change (facebook#38070)

Summary:
Pull Request resolved: facebook#38070

changelog:
[iOS][fix]: Correctly invalidate NSTextStorage when non layout related props change

Fixes: facebook#37944

Problem:
NSTextStorage was not invalidated if non-layout props were changed. So for example 'color' dynamically changed, it wouldn't get invalidated and font of incorrect color would be rendered on screen.

Reviewed By: javache

Differential Revision: D47019250

fbshipit-source-id: ba33d542dad2eaa0c3effcf827ad03f37fb11cc0

packages/react-native/ReactCommon/react/renderer/components/text/ParagraphLayoutManager.cpp

@@ -42,20 +42,22 @@ bool ParagraphLayoutManager::shoudMeasureString(
     AttributedString const &attributedString,
     ParagraphAttributes const &paragraphAttributes,
     LayoutConstraints layoutConstraints) const {
-  size_t newHash = folly::hash::hash_combine(
-      0,
-      textAttributedStringHashLayoutWise(attributedString),
-      paragraphAttributes);
+  size_t newParagraphInputHash =
+      folly::hash::hash_combine(0, attributedString, paragraphAttributes);
 
-  if (newHash != paragraphInputHash_) {
+  if (newParagraphInputHash != paragraphInputHash_) {
     // AttributedString or ParagraphAttributes have changed.
     // Must create new host text storage and trigger measure.
     hostTextStorage_ = textLayoutManager_->getHostTextStorage(
         attributedString, paragraphAttributes, layoutConstraints);
-    paragraphInputHash_ = newHash;
+    paragraphInputHash_ = newParagraphInputHash;
+
     return true; // Must measure again.
   }
 
+  // Detect the case when available width for Paragraph meaningfully changes.
+  // This is to prevent unnecessary re-creation of NSTextStorage on iOS.
+  // On Android, this is no-op.
   bool hasMaximumSizeChanged =
       layoutConstraints.maximumSize.width != lastAvailableWidth_;
   Float threshold = 0.01f;

packages/react-native/ReactCommon/react/renderer/components/text/ParagraphShadowNode.h

@@ -9,7 +9,6 @@
 
 #include <react/renderer/components/text/BaseTextShadowNode.h>
 #include <react/renderer/components/text/ParagraphEventEmitter.h>
-#include <react/renderer/components/text/ParagraphLayoutManager.h>
 #include <react/renderer/components/text/ParagraphProps.h>
 #include <react/renderer/components/text/ParagraphState.h>
 #include <react/renderer/components/view/ConcreteViewShadowNode.h>