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      1 /*
      2  * Copyright (C) 2012 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #include "config.h"
     32 #include "core/dom/shadow/SelectRuleFeatureSet.h"
     33 
     34 #include "core/css/CSSSelector.h"
     35 
     36 #include "wtf/BitVector.h"
     37 
     38 namespace WebCore {
     39 
     40 SelectRuleFeatureSet::SelectRuleFeatureSet()
     41     : m_featureFlags(0)
     42 {
     43 }
     44 
     45 void SelectRuleFeatureSet::add(const SelectRuleFeatureSet& featureSet)
     46 {
     47     m_cssRuleFeatureSet.add(featureSet.m_cssRuleFeatureSet);
     48     m_featureFlags |= featureSet.m_featureFlags;
     49 }
     50 
     51 void SelectRuleFeatureSet::clear()
     52 {
     53     m_cssRuleFeatureSet.clear();
     54     m_featureFlags = 0;
     55 }
     56 
     57 void SelectRuleFeatureSet::collectFeaturesFromSelector(const CSSSelector& selector)
     58 {
     59     m_cssRuleFeatureSet.collectFeaturesFromSelector(selector);
     60 
     61     switch (selector.pseudoType()) {
     62     case CSSSelector::PseudoChecked:
     63         setSelectRuleFeature(AffectedSelectorChecked);
     64         break;
     65     case CSSSelector::PseudoEnabled:
     66         setSelectRuleFeature(AffectedSelectorEnabled);
     67         break;
     68     case CSSSelector::PseudoDisabled:
     69         setSelectRuleFeature(AffectedSelectorDisabled);
     70         break;
     71     case CSSSelector::PseudoIndeterminate:
     72         setSelectRuleFeature(AffectedSelectorIndeterminate);
     73         break;
     74     case CSSSelector::PseudoLink:
     75         setSelectRuleFeature(AffectedSelectorLink);
     76         break;
     77     case CSSSelector::PseudoTarget:
     78         setSelectRuleFeature(AffectedSelectorTarget);
     79         break;
     80     case CSSSelector::PseudoVisited:
     81         setSelectRuleFeature(AffectedSelectorVisited);
     82         break;
     83     default:
     84         break;
     85     }
     86 }
     87 
     88 bool SelectRuleFeatureSet::checkSelectorsForClassChange(const SpaceSplitString& changedClasses) const
     89 {
     90     unsigned changedSize = changedClasses.size();
     91     for (unsigned i = 0; i < changedSize; ++i) {
     92         if (hasSelectorForClass(changedClasses[i]))
     93             return true;
     94     }
     95     return false;
     96 }
     97 
     98 bool SelectRuleFeatureSet::checkSelectorsForClassChange(const SpaceSplitString& oldClasses, const SpaceSplitString& newClasses) const
     99 {
    100     if (!oldClasses.size())
    101         return checkSelectorsForClassChange(newClasses);
    102 
    103     // Class vectors tend to be very short. This is faster than using a hash table.
    104     BitVector remainingClassBits;
    105     remainingClassBits.ensureSize(oldClasses.size());
    106 
    107     for (unsigned i = 0; i < newClasses.size(); ++i) {
    108         bool found = false;
    109         for (unsigned j = 0; j < oldClasses.size(); ++j) {
    110             if (newClasses[i] == oldClasses[j]) {
    111                 // Mark each class that is still in the newClasses so we can skip doing
    112                 // an n^2 search below when looking for removals. We can't break from
    113                 // this loop early since a class can appear more than once.
    114                 remainingClassBits.quickSet(j);
    115                 found = true;
    116             }
    117         }
    118         // Class was added.
    119         if (!found) {
    120             if (hasSelectorForClass(newClasses[i]))
    121                 return true;
    122         }
    123     }
    124 
    125     for (unsigned i = 0; i < oldClasses.size(); ++i) {
    126         if (remainingClassBits.quickGet(i))
    127             continue;
    128 
    129         // Class was removed.
    130         if (hasSelectorForClass(oldClasses[i]))
    131             return true;
    132     }
    133     return false;
    134 }
    135 
    136 }
    137 
    138