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// Copyright 2014 The Cobalt Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef COBALT_CSSOM_SELECTOR_H_
#define COBALT_CSSOM_SELECTOR_H_
#include <memory>
#include "cobalt/cssom/specificity.h"
namespace cobalt {
namespace cssom {
class ComplexSelector;
class CompoundSelector;
class SelectorVisitor;
class SimpleSelector;
// Selectors are patterns that match against elements in a tree, and as such
// form one of several technologies that can be used to select nodes in an XML
// document.
// https://www.w3.org/TR/selectors4/
class Selector {
public:
virtual ~Selector() {}
virtual void Accept(SelectorVisitor* visitor) = 0;
virtual ComplexSelector* AsComplexSelector() { return NULL; }
virtual CompoundSelector* AsCompoundSelector() { return NULL; }
virtual SimpleSelector* AsSimpleSelector() { return NULL; }
// A selector's specificity is calculated as follows:
// Count the number of ID selectors in the selector (A)
// Count the number of class selectors, attributes selectors, and
// pseudo-classes in the selector (B)
// Count the number of type selectors and pseudo-elements in the selector (C)
// https://www.w3.org/TR/selectors4/#specificity
virtual Specificity GetSpecificity() const = 0;
};
typedef std::vector<std::unique_ptr<Selector>> Selectors;
} // namespace cssom
} // namespace cobalt
#endif // COBALT_CSSOM_SELECTOR_H_