Fixed some issues with zero fontSizeMultiplier causing RCTSHadowText measure function to return an infinite height

Summary:The default value for fontSizeMultiplier was zero. Although this was usually overriden with the correct value (typically 1.0), it sometimes wasn't resulting in a divide-by-zero in the text height calculation.

This diff corrects that bug by setting 1.0 as the default, and guarding against zero values being set.

I also fixed some suspicious logic that seemed to assume the result of BOOL && CGFloat would be 0 or the CGFloat value, which is true in JS but not in C (it would always be 0 or 1).

Reviewed By: javache

Differential Revision: D3179196

fb-gh-sync-id: cc09b104c9087fc1a2f45d8d3f70af221c2ad823
fbshipit-source-id: cc09b104c9087fc1a2f45d8d3f70af221c2ad823

Libraries/Text/RCTShadowText.m

@@ -58,6 +58,7 @@ static css_dim_t RCTMeasure(void *context, float width, css_measure_mode_t width
     _opacity = 1.0;
     _cachedTextStorageWidth = -1;
     _cachedTextStorageWidthMode = -1;
+    _fontSizeMultiplier = 1.0;
     [[NSNotificationCenter defaultCenter] addObserver:self
                                              selector:@selector(contentSizeMultiplierDidChange:)
                                                  name:RCTUIManagerWillUpdateViewsDueToContentSizeMultiplierChangeNotification
@@ -92,8 +93,7 @@ static css_dim_t RCTMeasure(void *context, float width, css_measure_mode_t width
   UIEdgeInsets padding = self.paddingAsInsets;
   CGFloat width = self.frame.size.width - (padding.left + padding.right);
 
-  // HACK (t10802067)
+  NSTextStorage *textStorage = [self buildTextStorageForWidth:width widthMode:CSS_MEASURE_MODE_EXACTLY];
-  NSTextStorage *textStorage = [self buildTextStorageForWidth:width widthMode:isnan(width) ? CSS_MEASURE_MODE_UNDEFINED : CSS_MEASURE_MODE_EXACTLY];
   [applierBlocks addObject:^(NSDictionary<NSNumber *, RCTText *> *viewRegistry) {
     RCTText *view = viewRegistry[self.reactTag];
     view.textStorage = textStorage;
@@ -241,7 +241,7 @@ static css_dim_t RCTMeasure(void *context, float width, css_measure_mode_t width
 
   UIFont *font = [RCTConvert UIFont:nil withFamily:fontFamily
                                size:fontSize weight:fontWeight style:fontStyle
-                    scaleMultiplier:(_allowFontScaling && _fontSizeMultiplier > 0.0 ? _fontSizeMultiplier : 1.0)];
+                    scaleMultiplier:_allowFontScaling ? _fontSizeMultiplier : 1.0];
   [self _addAttribute:NSFontAttributeName withValue:font toAttributedString:attributedString];
   [self _addAttribute:NSKernAttributeName withValue:letterSpacing toAttributedString:attributedString];
   [self _addAttribute:RCTReactTagAttributeName withValue:self.reactTag toAttributedString:attributedString];
@@ -279,11 +279,13 @@ static css_dim_t RCTMeasure(void *context, float width, css_measure_mode_t width
     self.lineHeight = 0.0;
   }
 
+  CGFloat fontSizeMultiplier = _allowFontScaling ? _fontSizeMultiplier : 1.0;
+
   // check for lineHeight on each of our children, update the max as we go (in self.lineHeight)
   [attributedString enumerateAttribute:NSParagraphStyleAttributeName inRange:(NSRange){0, attributedString.length} options:0 usingBlock:^(id value, NSRange range, BOOL *stop) {
     if (value) {
       NSParagraphStyle *paragraphStyle = (NSParagraphStyle *)value;
-      CGFloat maximumLineHeight = round(paragraphStyle.maximumLineHeight / self.fontSizeMultiplier);
+      CGFloat maximumLineHeight = round(paragraphStyle.maximumLineHeight / fontSizeMultiplier);
       if (maximumLineHeight > self.lineHeight) {
         self.lineHeight = maximumLineHeight;
       }
@@ -299,7 +301,7 @@ static css_dim_t RCTMeasure(void *context, float width, css_measure_mode_t width
     NSMutableParagraphStyle *paragraphStyle = [NSMutableParagraphStyle new];
     paragraphStyle.alignment = _textAlign;
     paragraphStyle.baseWritingDirection = _writingDirection;
-    CGFloat lineHeight = round(_lineHeight * (_allowFontScaling && self.fontSizeMultiplier > 0.0 ? self.fontSizeMultiplier : 1.0));
+    CGFloat lineHeight = round(_lineHeight * fontSizeMultiplier);
     paragraphStyle.minimumLineHeight = lineHeight;
     paragraphStyle.maximumLineHeight = lineHeight;
     [attributedString addAttribute:NSParagraphStyleAttributeName
@@ -400,6 +402,10 @@ RCT_TEXT_PROPERTY(TextShadowColor, _textShadowColor, UIColor *);
 - (void)setFontSizeMultiplier:(CGFloat)fontSizeMultiplier
 {
   _fontSizeMultiplier = fontSizeMultiplier;
+  if (_fontSizeMultiplier == 0) {
+    RCTLogError(@"fontSizeMultiplier value must be > zero.");
+    _fontSizeMultiplier = 1.0;
+  }
   for (RCTShadowView *child in [self reactSubviews]) {
     if ([child isKindOfClass:[RCTShadowText class]]) {
       ((RCTShadowText *)child).fontSizeMultiplier = fontSizeMultiplier;

Libraries/Text/RCTTextManager.m

@@ -115,10 +115,9 @@ RCT_EXPORT_SHADOW_PROPERTY(textShadowColor, UIColor)
 
   /**
    * NOTE: this logic is included to support rich text editing inside multiline
-   * `<TextInput>` controls, a feature which is not yet supported in open source.
+   * `<TextInput>` controls. It is required in order to ensure that the
-   * It is required in order to ensure that the textStorage (aka attributed
+   * textStorage (aka attributed string) is copied over from the RCTShadowText
-   * string) is copied over from the RCTShadowText to the RCTText view in time
+   * to the RCTText view in time to be used to update the editable text content.
-   * to be used to update the editable text content.
    */
   if (textViewTagsToUpdate.count) {
 
@@ -136,9 +135,7 @@ RCT_EXPORT_SHADOW_PROPERTY(textShadowColor, UIColor)
       UIEdgeInsets padding = shadowText.paddingAsInsets;
       CGFloat width = shadowText.frame.size.width - (padding.left + padding.right);
 
-      // HACK (t10802067)
+      NSTextStorage *textStorage = [shadowText buildTextStorageForWidth:width widthMode:CSS_MEASURE_MODE_EXACTLY];
-      NSTextStorage *textStorage = [shadowText buildTextStorageForWidth:width widthMode:isnan(width) ? CSS_MEASURE_MODE_UNDEFINED : CSS_MEASURE_MODE_EXACTLY];
-
       [uiBlocks addObject:^(RCTUIManager *uiManager, NSDictionary<NSNumber *, RCTTextView *> *viewRegistry) {
         RCTTextView *textView = viewRegistry[reactTag];
         RCTText *text;