CSS Custom Properties (Variables)

Source/core/css/resolver/StyleBuilderCustom.cpp

Index: Source/core/css/resolver/StyleBuilderCustom.cpp
diff --git a/Source/core/css/resolver/StyleBuilderCustom.cpp b/Source/core/css/resolver/StyleBuilderCustom.cpp
index eefd6cc6d4ca7854247e16577902c80b892926b9..55530547b6b63cf943b9b754079eca5a2f64f6bc 100644
--- a/Source/core/css/resolver/StyleBuilderCustom.cpp
+++ b/Source/core/css/resolver/StyleBuilderCustom.cpp
@@ -44,6 +44,7 @@
 #include "core/StylePropertyShorthand.h"
 #include "core/css/BasicShapeFunctions.h"
 #include "core/css/CSSCursorImageValue.h"
+#include "core/css/CSSCustomVariableValue.h"
 #include "core/css/CSSGradientValue.h"
 #include "core/css/CSSGridTemplateAreasValue.h"
 #include "core/css/CSSHelper.h"
@@ -52,10 +53,15 @@
 #include "core/css/CSSPathValue.h"
 #include "core/css/CSSPrimitiveValueMappings.h"
 #include "core/css/CSSPropertyMetadata.h"
+#include "core/css/CSSReflectValue.h"

[Timothy Loh, 2015/07/23 08:11:47]

unused include?

 #include "core/css/Counter.h"
 #include "core/css/Pair.h"
 #include "core/css/StylePropertySet.h"
 #include "core/css/StyleRule.h"
+#include "core/css/parser/CSSParser.h"
+#include "core/css/parser/CSSParserTokenRange.h"
+#include "core/css/parser/CSSPropertyParser.h"
+#include "core/css/resolver/CSSVariableResolver.h"
 #include "core/css/resolver/ElementStyleResources.h"
 #include "core/css/resolver/FilterOperationResolver.h"
 #include "core/css/resolver/FontBuilder.h"
@@ -104,8 +110,18 @@ static inline bool isValidVisitedLinkProperty(CSSPropertyID id)
 
 } // namespace
 
+static bool hasVariableReference(CSSValue* value)
+{
+    return value->isPrimitiveValue() && toCSSPrimitiveValue(value)->primitiveType() == CSSPrimitiveValue::CSS_VARIABLE_REFERENCE;
+}
+
 void StyleBuilder::applyProperty(CSSPropertyID id, StyleResolverState& state, CSSValue* value)
 {
+    if (RuntimeEnabledFeatures::cssVariablesEnabled() /*&& state.documentUsesCSSVariables()*/ && id != CSSPropertyVariable && hasVariableReference(value)) {
+        CSSVariableResolver::resolveAndApplyVariableReferences(state, id, toCSSPrimitiveValue(value));
+        return;
+    }
+
     ASSERT_WITH_MESSAGE(!isShorthandProperty(id), "Shorthand property id = %d wasn't expanded at parsing time", id);
 
     bool isInherit = state.parentNode() && value->isInheritedValue();
@@ -798,6 +814,48 @@ void StyleBuilderFunctions::applyValueCSSPropertyWebkitTextOrientation(StyleReso
     state.setTextOrientation(*toCSSPrimitiveValue(value));
 }
 
+void StyleBuilderFunctions::applyValueCSSPropertyVariable(StyleResolverState& state, CSSValue* value)
+{
+    CSSCustomVariableValue* varVal = toCSSCustomVariableValue(value);
+    if (state.style()->variables()) {

[Timothy Loh, 2015/07/23 08:11:47]

It doesn't seem like this'll work correctly with inheritance. We point to the
same StyleVariableData as our parent when the StyleRareInheritedData is copied,
so we'll also update our parents' variables.

Maybe we should have ComputedStyle::removeVariable and
ComputedStyle::setVariable, which will do a null check and a hasOneRef check and
behave appropriately?

+        switch (varVal->id()) {
+        case CSSValueUnset:
+        case CSSValueInitial:
+            state.style()->variables()->removeVariable(varVal->name());
+            break;
+        case CSSValueInherit: {
+            StyleVariableData* parentVariables = state.parentStyle()->variables();
+            if (!parentVariables)
+                return;

[Timothy Loh, 2015/07/23 08:11:47]

The two nothing-to-do cases here should call removeVariable, otherwise the
following case probably won't work:

:lessspecific { --foo: var; }
#morespecific { --foo: inherit; }

<div id=morespecific class=lessspecific></div>

+            CSSVariableData* value = parentVariables->getVariable(varVal->name());
+            if (!value)
+                return;
+            state.style()->variables()->setVariable(varVal->name(), value);
+            break;
+        }
+        case CSSValueInternalVariableValue:
+            state.style()->variables()->setVariable(varVal->name(), varVal->value());
+        break;

[Timothy Loh, 2015/07/23 08:11:47]

indentation is off

+        default:
+            ASSERT_NOT_REACHED();
+        }
+    } else if (varVal->id() == CSSValueInternalVariableValue) {
+        RefPtr<StyleVariableData> variableData = state.parentStyle()->variables() ? state.parentStyle()->variables()->copy() : StyleVariableData::create();
+        variableData->setVariable(varVal->name(), varVal->value());
+        state.style()->setVariables(variableData.release());
+    }
+}
+
+void StyleBuilderFunctions::applyInheritCSSPropertyVariable(StyleResolverState& state)
+{
+    ASSERT_NOT_REACHED();
+}
+
+void StyleBuilderFunctions::applyInitialCSSPropertyVariable(StyleResolverState& state)
+{
+    ASSERT_NOT_REACHED();
+}
+
 void StyleBuilderFunctions::applyInheritCSSPropertyBaselineShift(StyleResolverState& state)
 {
     const SVGComputedStyle& parentSvgStyle = state.parentStyle()->svgStyle();