CSS Custom Properties (Variables)

Source/core/css/resolver/CSSVariableResolver.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CSSVariableResolver_h
+#define CSSVariableResolver_h
+
+#include "core/CSSPropertyNames.h"
+#include "core/css/parser/CSSParserToken.h"
+#include "wtf/HashSet.h"
+#include "wtf/text/AtomicString.h"
+#include "wtf/text/AtomicStringHash.h"
+
+namespace blink {
+
+class CSSPrimitiveValue;
+class StyleResolverState;
+class StyleVariableData;
+
+// TODO(leviw): Refactor to not just use static methods, and instead have private members.
+class CSSVariableResolver {
+public:
+    static void resolveVariableDefinitions(StyleResolverState&);
+    static void resolveAndApplyVariableReferences(StyleResolverState&, CSSPropertyID, CSSPrimitiveValue*);
+
+private:
+    enum ResolutionBehavior {
+        ResolvingVariableDefinitions,
+        DoNotResolveVariableDefinitions
+    };
+
+    CSSVariableResolver(const StyleVariableData*);
+    CSSVariableResolver(const StyleVariableData*, AtomicString& variable);
+
+    unsigned resolveVariableTokensRecursive(Vector<CSSParserToken>&, unsigned startOffset);
+    void resolveVariableReferencesFromTokens(Vector<CSSParserToken>& tokens);
+
+    const StyleVariableData* m_styleVariableData;
+    HashSet<AtomicString> m_variablesSeen;
+    bool m_cycleDetected;
+    ResolutionBehavior m_resolutionBehavior;
+};
+
+} // namespace blink
+
+#endif // CSSVariableResolver