Partial implementation of CSSVariablesMap for CSS Variables CSSOM

Source/core/css/StylePropertySet.cpp

Index: Source/core/css/StylePropertySet.cpp
diff --git a/Source/core/css/StylePropertySet.cpp b/Source/core/css/StylePropertySet.cpp
index 81467555886c2c1843a5b55395a29910d6d99ea4..fbde2a42095956bf8c09c469d8bbcbc1f2e2d3e8 100644
--- a/Source/core/css/StylePropertySet.cpp
+++ b/Source/core/css/StylePropertySet.cpp
@@ -22,6 +22,7 @@
 #include "config.h"
 #include "core/css/StylePropertySet.h"
 
+#include "RuntimeEnabledFeatures.h"
 #include "core/css/CSSParser.h"
 #include "core/css/CSSValuePool.h"
 #include "core/css/CSSVariableValue.h"
@@ -131,6 +132,26 @@ PassRefPtr<CSSValue> StylePropertySet::getPropertyCSSValue(CSSPropertyID propert
     return propertyAt(foundPropertyIndex).value();
 }
 
+unsigned StylePropertySet::variableCount() const
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    unsigned count = 0;
+    for (unsigned i = 0; i < propertyCount(); ++i) {
+        if (propertyAt(i).id() == CSSPropertyVariable)
+            count++;
+    }
+    return count;
+}
+
+String StylePropertySet::variableValue(const AtomicString& name) const
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    size_t index = findVariableIndex(name);
+    if (index == notFound)
+        return String();
+    return static_cast<CSSVariableValue*>(propertyAt(index).value())->value();
+}
+
 bool MutableStylePropertySet::removeShorthandProperty(CSSPropertyID propertyID)
 {
     StylePropertyShorthand shorthand = shorthandForProperty(propertyID);
@@ -265,6 +286,28 @@ unsigned getIndexInShorthandVectorForPrefixingVariant(const CSSProperty& propert
     return indexOfShorthandForLonghand(prefixedShorthand, matchingShorthandsForLonghand(prefixingVariant));
 }
 
+bool MutableStylePropertySet::setVariableValue(const AtomicString& name, const String& value, bool important)
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    if (value.isEmpty())
+        return removeVariable(name);
+
+    size_t index = findVariableIndex(name);
+    if (index != notFound) {
+        CSSValue* cssValue = m_propertyVector.at(index).value();
+        ASSERT(cssValue && cssValue->isVariableValue());
+        if (static_cast<CSSVariableValue*>(cssValue)->value() == value)

[esprehn, 2013/07/10 02:42:11]

Please add toCSSVariableValue() that does the cssValue->isVariableValue() ASSERT
internally. Just like our other ones. You shouldn't need to assert(cssValue)
here either, we'll just crash when you access value() anyway.

[alancutter (OOO until 2018), 2013/07/10 11:18:13]

Done.

+            return false;
+    }
+
+    CSSProperty property(CSSPropertyVariable, CSSVariableValue::create(name, value), important);
+    if (index == notFound)
+        m_propertyVector.append(property);
+    else
+        m_propertyVector.at(index) = property;
+    return true;
+}
+
 void MutableStylePropertySet::appendPrefixingVariantProperty(const CSSProperty& property)
 {
     m_propertyVector.append(property);
@@ -442,6 +485,8 @@ bool MutableStylePropertySet::removePropertiesInSet(const CSSPropertyID* set, un
 
 int StylePropertySet::findPropertyIndex(CSSPropertyID propertyID) const
 {
+    // CSS variables share the same property ID, findVariableIndex() should be used for variables instead.
+    ASSERT(propertyID != CSSPropertyVariable);
     for (int n = propertyCount() - 1 ; n >= 0; --n) {
         if (propertyID == propertyAt(n).id()) {
             // Only enabled properties should be part of the style.
@@ -452,6 +497,17 @@ int StylePropertySet::findPropertyIndex(CSSPropertyID propertyID) const
     return -1;
 }
 
+size_t StylePropertySet::findVariableIndex(const AtomicString& name) const
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    for (int i = propertyCount() - 1; i >= 0; --i) {
+        const PropertyReference& property = propertyAt(i);
+        if (property.id() == CSSPropertyVariable && static_cast<const CSSVariableValue*>(property.value())->name() == name)
+            return i;
+    }
+    return notFound;
+}
+
 CSSProperty* MutableStylePropertySet::findCSSPropertyWithID(CSSPropertyID propertyID)
 {
     int foundPropertyIndex = findPropertyIndex(propertyID);
@@ -496,6 +552,29 @@ void MutableStylePropertySet::removeEquivalentProperties(const CSSStyleDeclarati
         removeProperty(propertiesToRemove[i]);
 }
 
+bool MutableStylePropertySet::removeVariable(const AtomicString& name)
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    size_t index = findVariableIndex(name);
+    if (index == notFound)
+        return false;
+    m_propertyVector.remove(index);
+    return true;
+}
+
+bool MutableStylePropertySet::clearVariables()
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    bool removed = false;
+    for (size_t i = propertyCount(); i--;) {
+        if (propertyAt(i).id() == CSSPropertyVariable) {
+            removed = true;
+            m_propertyVector.remove(i);
+        }
+    }
+    return removed;

[esprehn, 2013/07/10 02:42:11]

This can just be 

CSSPropertyID variableId = CSSPropertyVariable;
return removePropertiesInSet(&variableId, 1);

It'll be much better if you have a lot of variables too since you don't
constantly copy the stuff inside the vector.

[alancutter (OOO until 2018), 2013/07/10 11:18:13]

Fantastic! Done.

+}
+
 PassRefPtr<MutableStylePropertySet> StylePropertySet::mutableCopy() const
 {
     return adoptRef(new MutableStylePropertySet(*this));