refactor(ios): optimize text rendering performance and thread safety (Tencent#4490)

* refactor(ios): optimize text rendering performance and thread safety

* fix(ios): handle null exception in Hermes uncaught exception callback

Author: wwwcg

driver/js/src/napi/hermes/hermes_ctx.cc

@@ -91,9 +91,12 @@ static void HandleJsException(std::shared_ptr<Scope> scope, std::shared_ptr<Herm
   FOOTSTONE_DCHECK(engine);
   if (engine) {
       auto callback = engine->GetVM()->GetUncaughtExceptionCallback();
+      if (!callback) {
+        return;
+      }
       auto context = scope->GetContext();
       footstone::string_view description("Hermes Engine JS Exception");
-      footstone::string_view stack(exception->GetMessage());
+      footstone::string_view stack(exception ? exception->GetMessage() : "");
       callback(scope->GetBridge(), description, stack);
   }
 }

renderer/native/ios/renderer/component/text/HippyShadowText.mm

@@ -57,6 +57,21 @@
 CGFloat const HippyTextAutoSizeGranularity = 0.001;
 static const CGFloat gDefaultFontSize = 14.0;
 
+static UIFont *HippyCreateFontOnMainThread(NSString *fontFamily, CGFloat size) {
+    if (!fontFamily) {
+        return nil;
+    }
+    if ([NSThread isMainThread]) {
+        return [UIFont fontWithName:fontFamily size:size];
+    } else {
+        __block UIFont *font = nil;
+        dispatch_sync(dispatch_get_main_queue(), ^{
+            font = [UIFont fontWithName:fontFamily size:size];
+        });
+        return font;
+    }
+}
+
 static BOOL DirtyTextEqual(BOOL v1, BOOL v2) {
     return v1 == v2;
 }
@@ -376,35 +391,42 @@ - (void)applyConfirmedLayoutDirectionToSubviews:(hippy::Direction)confirmedLayou
 }
 
 - (NSTextStorage *)buildTextStorageForWidth:(CGFloat)width widthMode:(hippy::LayoutMeasureMode)widthMode {
-    @synchronized (self) {
-        if (isnan(width)) {
-            width = 0;
-        }
+    if (isnan(width)) {
+        width = 0;
+    }
 
+    @synchronized (self) {
         if (_cachedTextStorage && width == _cachedTextStorageWidth && widthMode == _cachedTextStorageWidthMode) {
             return _cachedTextStorage;
         }
+    }
 
-        // textContainer
-        NSTextContainer *textContainer = [NSTextContainer new];
-        textContainer.lineFragmentPadding = 0.0;
+    // Build attributed string outside of synchronized block to avoid potential deadlock
+    // when creating UIFont instances on the main thread.
+    NSAttributedString *baseAttributedString = self.attributedString;
 
-        if (_numberOfLines > 0) {
-            textContainer.lineBreakMode = _ellipsizeMode;
-        } else {
-            textContainer.lineBreakMode = NSLineBreakByClipping;
-        }
+    // textContainer
+    NSTextContainer *textContainer = [NSTextContainer new];
+    textContainer.lineFragmentPadding = 0.0;
 
-        textContainer.maximumNumberOfLines = _numberOfLines;
-        textContainer.size = (CGSize) { widthMode == hippy::LayoutMeasureMode::Undefined ? CGFLOAT_MAX : width, CGFLOAT_MAX };
-        
-        // layoutManager && textStorage
-        NSLayoutManager *layoutManager = [NSLayoutManager new];
-        NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:self.attributedString];
-        [textStorage addLayoutManager:layoutManager];
-        
-        layoutManager.delegate = self;
-        [layoutManager addTextContainer:textContainer];
+    if (_numberOfLines > 0) {
+        textContainer.lineBreakMode = _ellipsizeMode;
+    } else {
+        textContainer.lineBreakMode = NSLineBreakByClipping;
+    }
+
+    textContainer.maximumNumberOfLines = _numberOfLines;
+    textContainer.size = (CGSize) { widthMode == hippy::LayoutMeasureMode::Undefined ? CGFLOAT_MAX : width, CGFLOAT_MAX };
+    
+    // layoutManager && textStorage
+    NSLayoutManager *layoutManager = [NSLayoutManager new];
+    NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:baseAttributedString];
+    [textStorage addLayoutManager:layoutManager];
+    
+    layoutManager.delegate = self;
+    [layoutManager addTextContainer:textContainer];
+
+    @synchronized (self) {
         // start clean collection for this layout build
         [_pendingBaselineOffsets removeAllObjects];
         [_pendingAttachmentBaselineBottoms removeAllObjects];
@@ -459,9 +481,9 @@ - (NSTextStorage *)buildTextStorageForWidth:(CGFloat)width widthMode:(hippy::Lay
         _cachedTextStorageWidth = width;
         _cachedTextStorageWidthMode = widthMode;
         _cachedTextStorage = textStorage;
-
-        return textStorage;
     }
+
+    return textStorage;
 }
 
 - (void)dirtyText:(BOOL)needToDoLayout {
@@ -563,7 +585,7 @@ - (NSAttributedString *)_attributedStringWithStyleInfo:(HippyAttributedStringSty
 
     UIFont *f = nil;
     if (styleInfo.fontFamily) {
-        f = [UIFont fontWithName:styleInfo.fontFamily size:[styleInfo.fontSize floatValue]];
+        f = HippyCreateFontOnMainThread(styleInfo.fontFamily, [styleInfo.fontSize floatValue]);
     }
 
     UIFont *font = [HippyFont updateFont:f