Proper support for multiple text decorations.

Source/core/rendering/style/RenderStyle.cpp

Index: Source/core/rendering/style/RenderStyle.cpp
diff --git a/Source/core/rendering/style/RenderStyle.cpp b/Source/core/rendering/style/RenderStyle.cpp
index a4cb88432c2c76f68e13a4f1be202f7770eaf843..7739040ec894288af70c784accd619a476a645b8 100644
--- a/Source/core/rendering/style/RenderStyle.cpp
+++ b/Source/core/rendering/style/RenderStyle.cpp
@@ -28,6 +28,7 @@
 #include "core/css/resolver/StyleResolver.h"
 #include "core/rendering/RenderTheme.h"
 #include "core/rendering/TextAutosizer.h"
+#include "core/rendering/style/AppliedTextDecorationList.h"
 #include "core/rendering/style/ContentData.h"
 #include "core/rendering/style/CursorList.h"
 #include "core/rendering/style/QuotesData.h"
@@ -657,14 +658,15 @@ StyleDifference RenderStyle::repaintOnlyDiff(const RenderStyle* other, unsigned&
     }
 
     if (inherited->color != other->inherited->color
-        || inherited_flags._text_decorations != other->inherited_flags._text_decorations
+        || inherited_flags.m_textUnderline != other->inherited_flags.m_textUnderline
         || visual->textDecoration != other->visual->textDecoration
         || rareNonInheritedData->m_textDecorationStyle != other->rareNonInheritedData->m_textDecorationStyle
         || rareNonInheritedData->m_textDecorationColor != other->rareNonInheritedData->m_textDecorationColor
         || rareInheritedData->textFillColor() != other->rareInheritedData->textFillColor()
         || rareInheritedData->textStrokeColor() != other->rareInheritedData->textStrokeColor()
         || rareInheritedData->textEmphasisColor() != other->rareInheritedData->textEmphasisColor()
-        || rareInheritedData->textEmphasisFill != other->rareInheritedData->textEmphasisFill)
+        || rareInheritedData->textEmphasisFill != other->rareInheritedData->textEmphasisFill
+        || rareInheritedData->appliedTextDecorations != other->rareInheritedData->appliedTextDecorations)
         return StyleDifferenceRepaintIfTextOrColorChange;
 
     // Cursors are not checked, since they will be set appropriately in response to mouse events,
@@ -1186,6 +1188,22 @@ float RenderStyle::computedFontSize() const { return fontDescription().computedS
 int RenderStyle::fontSize() const { return fontDescription().computedPixelSize(); }
 FontWeight RenderStyle::fontWeight() const { return fontDescription().weight(); }
 
+TextDecoration RenderStyle::textDecorationsInEffect() const
+{
+    int decorations = 0;
+
+    if (appliedTextUnderline())
+        decorations |= TextDecorationUnderline;
+
+    const AppliedTextDecorationList* applied = appliedTextDecorations();
+
+    if (applied)
+        for (size_t i = 0; i < applied->size(); ++i)
+            decorations |= applied->at(i).line();

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

This needs braces, we also prefer early return.

if (!applied)
  return 0;

for (...)
  ...

return...

+
+    return static_cast<TextDecoration>(decorations);
+}
+
 float RenderStyle::wordSpacing() const { return fontDescription().wordSpacing(); }
 float RenderStyle::letterSpacing() const { return fontDescription().letterSpacing(); }
 
@@ -1281,6 +1299,79 @@ void RenderStyle::setFontWeight(FontWeight weight)
     font().update(currentFontSelector);
 }
 
+void RenderStyle::setTextDecorationsInEffect(TextDecoration decorations)
+{
+    clearAppliedTextDecorations();
+
+    if (decorations & TextDecorationUnderline)
+        addAppliedTextDecoration(TextDecorationUnderline);
+    if (decorations & TextDecorationOverline)
+        addAppliedTextDecoration(TextDecorationOverline);
+    if (decorations & TextDecorationLineThrough)
+        addAppliedTextDecoration(TextDecorationLineThrough);
+}
+
+void RenderStyle::addAppliedTextDecoration(TextDecoration decoration)
+{
+    if (!appliedTextDecorations() && decoration == TextDecorationUnderline) {
+        // To save memory, we don't use AppliedTextDecoration objects in the
+        // common case of a single solid underline with the current color. Instead,
+        // we set a bit to indicate that an underline must be drawn during painting.
+        inherited_flags.m_textUnderline = true;
+        return;
+    }
+
+    addAppliedTextDecoration(AppliedTextDecoration(decoration, TextDecorationStyleSolid, color()));
+}
+
+void RenderStyle::addAppliedTextDecoration(const AppliedTextDecoration& decoration)
+{
+    RefPtr<AppliedTextDecorationList>& list = rareInheritedData.access()->appliedTextDecorations;
+
+    if (!list)
+        list = AppliedTextDecorationList::create();
+    else if (!list->hasOneRef())
+        list = list->copy();
+
+    list->append(decoration);
+}
+
+void RenderStyle::applyTextDecoration(TextDecoration decoration, TextDecorationStyle style, const StyleColor& styleColor)
+{
+    const bool isSimple = style == TextDecorationStyleSolid && styleColor.isCurrentColor();

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

remove const

+
+    if (isSimple)
+        addAppliedTextDecoration(decoration);
+    else
+        addAppliedTextDecoration(AppliedTextDecoration(decoration, style, styleColor.resolve(color())));
+}
+
+void RenderStyle::applyTextDecorations()
+{
+    if (textDecoration() == TextDecorationNone)
+        return;
+
+    TextDecorationStyle style = textDecorationStyle();
+    StyleColor styleColor = visitedDependentDecorationStyleColor();
+
+    const int decorations = textDecoration();

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

no const

+
+    if (decorations & TextDecorationUnderline)
+        applyTextDecoration(TextDecorationUnderline, style, styleColor);
+    if (decorations & TextDecorationOverline)
+        applyTextDecoration(TextDecorationOverline, style, styleColor);
+    if (decorations & TextDecorationLineThrough)
+        applyTextDecoration(TextDecorationLineThrough, style, styleColor);
+}
+
+void RenderStyle::clearAppliedTextDecorations()
+{
+    inherited_flags.m_textUnderline = false;
+
+    if (rareInheritedData->appliedTextDecorations)
+        rareInheritedData.access()->appliedTextDecorations = nullptr;
+}
+
 void RenderStyle::getShadowExtent(const ShadowList* shadowList, LayoutUnit &top, LayoutUnit &right, LayoutUnit &bottom, LayoutUnit &left) const
 {
     top = 0;
@@ -1358,10 +1449,29 @@ void RenderStyle::getShadowVerticalExtent(const ShadowList* shadowList, LayoutUn
     }
 }
 
-StyleColor RenderStyle::visitedDependentDecorationColor() const
+StyleColor RenderStyle::visitedDependentDecorationStyleColor() const
+{
+    const bool visitedLink = insideLink() == InsideVisitedLink;

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

ditto

+
+    StyleColor styleColor = visitedLink ? visitedLinkTextDecorationColor() : textDecorationColor();
+
+    if (!styleColor.isCurrentColor())
+        return styleColor;
+
+    if (textStrokeWidth() > 0) {

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

Remove > 0, can this be negative?

+        // Prefer stroke color if possible but not if it's fully transparent.
+        StyleColor textStrokeStyleColor = visitedLink ? visitedLinkTextStrokeColor() : textStrokeColor();
+        if (!textStrokeStyleColor.isCurrentColor() && textStrokeStyleColor.color().alpha())
+            return textStrokeStyleColor;
+    }
+
+    return visitedLink ? visitedLinkTextFillColor() : textFillColor();
+}
+
+Color RenderStyle::visitedDependentDecorationColor() const
 {
-    // Text decoration color fallback is handled in RenderObject::decorationColor.
-    return insideLink() == InsideVisitedLink ? visitedLinkTextDecorationColor() : textDecorationColor();
+    const bool visitedLink = insideLink() == InsideVisitedLink;
+    return visitedDependentDecorationStyleColor().resolve(visitedLink ? visitedLinkColor() : color());
 }
 
 Color RenderStyle::colorIncludingFallback(int colorProperty, bool visitedLink) const