Proper support for multiple text decorations.

Source/core/rendering/style/RenderStyle.h

Index: Source/core/rendering/style/RenderStyle.h
diff --git a/Source/core/rendering/style/RenderStyle.h b/Source/core/rendering/style/RenderStyle.h
index c09a10105916cd4a076ba7d1a7f7f20cd3781212..1c87676e1f56e8c97ea431fa659ca3f6b541f935 100644
--- a/Source/core/rendering/style/RenderStyle.h
+++ b/Source/core/rendering/style/RenderStyle.h
@@ -96,6 +96,8 @@ using std::max;
 
 class FilterOperations;
 
+class AppliedTextDecoration;
+class AppliedTextDecorationList;
 class BorderData;
 class CounterContent;
 class CursorList;
@@ -162,7 +164,7 @@ protected:
                 && (_visibility == other._visibility)
                 && (_text_align == other._text_align)
                 && (_text_transform == other._text_transform)
-                && (_text_decorations == other._text_decorations)
+                && (m_textUnderline == other.m_textUnderline)
                 && (_cursor_style == other._cursor_style)
                 && (_direction == other._direction)
                 && (_white_space == other._white_space)
@@ -184,24 +186,24 @@ protected:
         unsigned _visibility : 2; // EVisibility
         unsigned _text_align : 4; // ETextAlign
         unsigned _text_transform : 2; // ETextTransform
-        unsigned _text_decorations : TextDecorationBits;
+        unsigned m_textUnderline : 1;
         unsigned _cursor_style : 6; // ECursor
         unsigned _direction : 1; // TextDirection
         unsigned _white_space : 3; // EWhiteSpace
-        // 32 bits
         unsigned _border_collapse : 1; // EBorderCollapse
         unsigned _box_direction : 1; // EBoxDirection (CSS3 box_direction property, flexible box layout module)
+        // 32 bits
 
         // non CSS2 inherited
         unsigned m_rtlOrdering : 1; // Order
         unsigned m_printColorAdjust : PrintColorAdjustBits;
         unsigned _pointerEvents : 4; // EPointerEvents
         unsigned _insideLink : 2; // EInsideLink
-        // 43 bits
+        // 40 bits
 
         // CSS Text Layout Module Level 3: Vertical writing support
         unsigned m_writingMode : 2; // WritingMode
-        // 45 bits
+        // 42 bits
     } inherited_flags;
 
 // don't inherit
@@ -301,7 +303,7 @@ protected:
         inherited_flags._visibility = initialVisibility();
         inherited_flags._text_align = initialTextAlign();
         inherited_flags._text_transform = initialTextTransform();
-        inherited_flags._text_decorations = initialTextDecoration();
+        inherited_flags.m_textUnderline = false;
         inherited_flags._cursor_style = initialCursor();
         inherited_flags._direction = initialDirection();
         inherited_flags._white_space = initialWhiteSpace();
@@ -579,7 +581,10 @@ public:
     TextAlignLast textAlignLast() const { return static_cast<TextAlignLast>(rareInheritedData->m_textAlignLast); }
     TextJustify textJustify() const { return static_cast<TextJustify>(rareInheritedData->m_textJustify); }
     ETextTransform textTransform() const { return static_cast<ETextTransform>(inherited_flags._text_transform); }
-    TextDecoration textDecorationsInEffect() const { return static_cast<TextDecoration>(inherited_flags._text_decorations); }
+    TextDecoration textDecorationsInEffect() const;
+    TextDecoration appliedTextUnderline() const { return static_cast<TextDecoration>(inherited_flags.m_textUnderline); }

[esprehn, 2014/03/31 17:41:24]

Instead of this you can encapsulate the optimization by returning a static const
Vector<AppliedTextDecoration> that just contains an underline. You can share
that Vector between all RenderStyles.


const AppliedTextDecorationList* appliedTextDecorations()
{
  DECLARE_STATIC_LOCAL(Vector<AppliedTextDecoration>, empty, ());
  DECLARE_STATIC_LOCAL(Vector<AppliedTextDecoration>, underline, (...));
  if (!inherited_flags.m_textUnderline &&
!rareInheritedData->appliedTextDecorations.size())
      return empty;
  if (inherited_flags.m_textUnderline &&
!rareInheritedData->appliedTextDecorations.size())
      return underline;
  return *rareInheritedData->appliedTextDecorations;
}

I would materialize the single underline inside the Vector too as the first
element.

[andersr, 2014/04/01 17:07:54]

Note that I have not fully addressed this issue in Patch Set 3. (I've addressed
all other issues, though).

AppliedTextDecoration objects contain the resolved Color for the decoration,
whereas the color for the simple underline is resolved during painting. If we
are to "migrate" the simple underline into the rare list once rare decorations
appear, then we need to resolve the Color during style adjusting instead. In
other words, we need to implement RenderObject::underlineColor during style
adjustment. Is that possible?

+    const AppliedTextDecorationList* appliedTextDecorations() const { return rareInheritedData->appliedTextDecorations.get(); }

[esprehn, 2014/03/31 17:41:24]

const Vector<AppliedTextDecoration>&, reference not pointer.

+    bool hasAppliedTextDecorations() const { return appliedTextUnderline() || appliedTextDecorations(); }
     TextDecoration textDecoration() const { return static_cast<TextDecoration>(visual->textDecoration); }
     TextUnderlinePosition textUnderlinePosition() const { return static_cast<TextUnderlinePosition>(rareInheritedData->m_textUnderlinePosition); }
     TextDecorationStyle textDecorationStyle() const { return static_cast<TextDecorationStyle>(rareNonInheritedData->m_textDecorationStyle); }
@@ -1107,8 +1112,12 @@ public:
     void setTextAlignLast(TextAlignLast v) { SET_VAR(rareInheritedData, m_textAlignLast, v); }
     void setTextJustify(TextJustify v) { SET_VAR(rareInheritedData, m_textJustify, v); }
     void setTextTransform(ETextTransform v) { inherited_flags._text_transform = v; }
-    void addToTextDecorationsInEffect(TextDecoration v) { inherited_flags._text_decorations |= v; }
-    void setTextDecorationsInEffect(TextDecoration v) { inherited_flags._text_decorations = v; }
+    void setTextDecorationsInEffect(TextDecoration);
+    void addAppliedTextDecoration(TextDecoration);
+    void addAppliedTextDecoration(const AppliedTextDecoration&);
+    void applyTextDecoration(TextDecoration, TextDecorationStyle, const StyleColor&);
+    void applyTextDecorations();
+    void clearAppliedTextDecorations();
     void setTextDecoration(TextDecoration v) { SET_VAR(visual, textDecoration, v); }
     void setTextUnderlinePosition(TextUnderlinePosition v) { SET_VAR(rareInheritedData, m_textUnderlinePosition, v); }
     void setTextDecorationStyle(TextDecorationStyle v) { SET_VAR(rareNonInheritedData, m_textDecorationStyle, v); }
@@ -1508,7 +1517,8 @@ public:
     bool lastChildState() const { return noninherited_flags.lastChildState; }
     void setLastChildState() { setUnique(); noninherited_flags.lastChildState = true; }
 
-    StyleColor visitedDependentDecorationColor() const;
+    StyleColor visitedDependentDecorationStyleColor() const;
+    Color visitedDependentDecorationColor() const;
     Color visitedDependentColor(int colorProperty) const;
 
     void setHasExplicitlyInheritedProperties() { noninherited_flags.explicitInheritance = true; }