CSSValue Immediates: Change RefPtr<CSSValue> to store tagged pointers

Source/core/css/CSSValue.cpp

 /*
  * Copyright (C) 2011 Andreas Kling (kling@webkit.org)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 47 matching lines @@
 
 struct SameSizeAsCSSValue : public RefCountedWillBeGarbageCollectedFinalized<SameSizeAsCSSValue>
 {
     uint32_t bitfields;
 };
 
 static_assert(sizeof(CSSValue) <= sizeof(SameSizeAsCSSValue), "CSSValue should stay small");
 
 bool CSSValue::isImplicitInitialValue() const
 {
-    return m_classType == InitialClass && toCSSInitialValue(this)->isImplicit();
+    return !isTaggedPtr() && classType() == InitialClass && toCSSInitialValue(this)->isImplicit();
 }
 
 bool CSSValue::hasFailedOrCanceledSubresources() const
 {
+    if (isTaggedPtr())
+        return false;
+
     if (isValueList())
         return toCSSValueList(this)->hasFailedOrCanceledSubresources();
     if (classType() == FontFaceSrcClass)
         return toCSSFontFaceSrcValue(this)->hasFailedOrCanceledSubresources();
     if (classType() == ImageClass)
         return toCSSImageValue(this)->hasFailedOrCanceledSubresources();
     if (classType() == CrossfadeClass)
         return toCSSCrossfadeValue(this)->hasFailedOrCanceledSubresources();
     if (classType() == ImageSetClass)
         return toCSSImageSetValue(this)->hasFailedOrCanceledSubresources();
 
     return false;
 }
 
 template<class ChildClassType>
 inline static bool compareCSSValues(const CSSValue& first, const CSSValue& second)
 {
     return static_cast<const ChildClassType&>(first).equals(static_cast<const ChildClassType&>(second));
 }
 
 bool CSSValue::equals(const CSSValue& other) const
 {
+    if (isTaggedPtr() && other.isTaggedPtr())
+        return this == &other;
+
+    if (isTaggedPtr() || other.isTaggedPtr())
+        return compareCSSValues<CSSPrimitiveValue>(*this, other);
+
     if (m_classType == other.m_classType) {
         switch (m_classType) {
         case BorderImageSliceClass:
             return compareCSSValues<CSSBorderImageSliceValue>(*this, other);
         case CanvasClass:
             return compareCSSValues<CSSCanvasValue>(*this, other);
         case CursorImageClass:
             return compareCSSValues<CSSCursorImageValue>(*this, other);
         case FontFaceSrcClass:
             return compareCSSValues<CSSFontFaceSrcValue>(*this, other);
@@ skipping 48 matching lines @@
         default:
             ASSERT_NOT_REACHED();
             return false;
         }
     }
     return false;
 }
 
 String CSSValue::cssText() const
 {
+    if (isTaggedPtr())
+        return toCSSPrimitiveValue(this)->customCSSText();
+
     switch (classType()) {
     case BorderImageSliceClass:
         return toCSSBorderImageSliceValue(this)->customCSSText();
     case CanvasClass:
         return toCSSCanvasValue(this)->customCSSText();
     case CursorImageClass:
         return toCSSCursorImageValue(this)->customCSSText();
     case FontFaceSrcClass:
         return toCSSFontFaceSrcValue(this)->customCSSText();
     case FontFeatureClass:
@@ skipping 44 matching lines @@
         return toCSSSVGDocumentValue(this)->customCSSText();
     case CSSContentDistributionClass:
         return toCSSContentDistributionValue(this)->customCSSText();
     }
     ASSERT_NOT_REACHED();
     return String();
 }
 
 void CSSValue::destroy()
 {
+    if (isTaggedPtr())
+        return;
+
     switch (classType()) {
     case BorderImageSliceClass:
         delete toCSSBorderImageSliceValue(this);
         return;
     case CanvasClass:
         delete toCSSCanvasValue(this);
         return;
     case CursorImageClass:
         delete toCSSCursorImageValue(this);
         return;
@@ skipping 71 matching lines @@
         return;
     case CSSContentDistributionClass:
         delete toCSSContentDistributionValue(this);
         return;
     }
     ASSERT_NOT_REACHED();
 }
 
 void CSSValue::finalizeGarbageCollectedObject()
 {
+    if (isTaggedPtr())
+        return;
+
     switch (classType()) {
     case BorderImageSliceClass:
         toCSSBorderImageSliceValue(this)->~CSSBorderImageSliceValue();
         return;
     case CanvasClass:
         toCSSCanvasValue(this)->~CSSCanvasValue();
         return;
     case CursorImageClass:
         toCSSCursorImageValue(this)->~CSSCursorImageValue();
         return;
@@ skipping 71 matching lines @@
         return;
     case CSSContentDistributionClass:
         toCSSContentDistributionValue(this)->~CSSContentDistributionValue();
         return;
     }
     ASSERT_NOT_REACHED();
 }
 
 DEFINE_TRACE(CSSValue)
 {
+    if (isTaggedPtr())
+        return;
+
     switch (classType()) {
     case BorderImageSliceClass:
         toCSSBorderImageSliceValue(this)->traceAfterDispatch(visitor);
         return;
     case CanvasClass:
         toCSSCanvasValue(this)->traceAfterDispatch(visitor);
         return;
     case CursorImageClass:
         toCSSCursorImageValue(this)->traceAfterDispatch(visitor);
         return;
@@ skipping 69 matching lines @@
     case CSSSVGDocumentClass:
         toCSSSVGDocumentValue(this)->traceAfterDispatch(visitor);
         return;
     case CSSContentDistributionClass:
         toCSSContentDistributionValue(this)->traceAfterDispatch(visitor);
         return;
     }
     ASSERT_NOT_REACHED();
 }
 
-}
+} // namespace blink