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/*
* Copyright 2015 Google Inc. 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_SPECIFICITY_H_
#define COBALT_CSSOM_SPECIFICITY_H_
#include "base/basictypes.h"
#include "base/logging.h"
namespace cobalt {
namespace cssom {
// 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
// When adding two specificities, clampping the result at each field (A, B and
// C).
class Specificity {
public:
Specificity() {
v_[0] = 0;
v_[1] = 0;
v_[2] = 0;
}
Specificity(int8 a, int8 b, int8 c) {
DCHECK_GE(a, 0) << "Specificity field cannot be negative.";
DCHECK_GE(b, 0) << "Specificity field cannot be negative.";
DCHECK_GE(c, 0) << "Specificity field cannot be negative.";
v_[0] = a;
v_[1] = b;
v_[2] = c;
}
// Adds the value of another specificity to self.
void AddFrom(const Specificity& rhs);
// Specificity fields are compared lexicographically.
bool operator<(const Specificity& rhs) const {
return v_[0] < rhs.v_[0] ||
(v_[0] == rhs.v_[0] &&
(v_[1] < rhs.v_[1] || (v_[1] == rhs.v_[1] && v_[2] < rhs.v_[2])));
}
bool operator>(const Specificity& rhs) const {
return v_[0] > rhs.v_[0] ||
(v_[0] == rhs.v_[0] &&
(v_[1] > rhs.v_[1] || (v_[1] == rhs.v_[1] && v_[2] > rhs.v_[2])));
}
bool operator==(const Specificity& rhs) const {
return v_[0] == rhs.v_[0] && v_[1] == rhs.v_[1] && v_[2] == rhs.v_[2];
}
private:
int8 v_[3];
};
} // namespace cssom
} // namespace cobalt
#endif // COBALT_CSSOM_SPECIFICITY_H_