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      1 /*
      2  * Copyright (C) 2014 Google Inc. All rights reserved.
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      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
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      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
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     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
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     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 #ifndef DescendantInvalidationSet_h
     32 #define DescendantInvalidationSet_h
     33 
     34 #include "platform/heap/Handle.h"
     35 #include "wtf/Forward.h"
     36 #include "wtf/HashSet.h"
     37 #include "wtf/RefCounted.h"
     38 #include "wtf/RefPtr.h"
     39 #include "wtf/text/AtomicStringHash.h"
     40 #include "wtf/text/StringHash.h"
     41 
     42 namespace blink {
     43 
     44 class Element;
     45 
     46 // Tracks data to determine which elements of a DOM subtree need to have style
     47 // recalculated.
     48 class DescendantInvalidationSet FINAL : public RefCountedWillBeGarbageCollected<DescendantInvalidationSet> {
     49 public:
     50     static PassRefPtrWillBeRawPtr<DescendantInvalidationSet> create()
     51     {
     52         return adoptRefWillBeNoop(new DescendantInvalidationSet);
     53     }
     54 
     55     bool invalidatesElement(Element&) const;
     56 
     57     void combine(const DescendantInvalidationSet& other);
     58 
     59     void addClass(const AtomicString& className);
     60     void addId(const AtomicString& id);
     61     void addTagName(const AtomicString& tagName);
     62     void addAttribute(const AtomicString& attributeLocalName);
     63 
     64     void setWholeSubtreeInvalid();
     65     bool wholeSubtreeInvalid() const { return m_allDescendantsMightBeInvalid; }
     66 
     67     void setTreeBoundaryCrossing() { m_treeBoundaryCrossing = true; }
     68     bool treeBoundaryCrossing() const { return m_treeBoundaryCrossing; }
     69 
     70     void setCustomPseudoInvalid() { m_customPseudoInvalid = true; }
     71     bool customPseudoInvalid() const { return m_customPseudoInvalid; }
     72 
     73     bool isEmpty() const { return !m_classes && !m_ids && !m_tagNames && !m_attributes; }
     74 
     75     void trace(Visitor*);
     76 
     77 #ifndef NDEBUG
     78     void show() const;
     79 #endif
     80 
     81 private:
     82     DescendantInvalidationSet();
     83 
     84     WillBeHeapHashSet<AtomicString>& ensureClassSet();
     85     WillBeHeapHashSet<AtomicString>& ensureIdSet();
     86     WillBeHeapHashSet<AtomicString>& ensureTagNameSet();
     87     WillBeHeapHashSet<AtomicString>& ensureAttributeSet();
     88 
     89     // FIXME: optimize this if it becomes a memory issue.
     90     OwnPtrWillBeMember<WillBeHeapHashSet<AtomicString> > m_classes;
     91     OwnPtrWillBeMember<WillBeHeapHashSet<AtomicString> > m_ids;
     92     OwnPtrWillBeMember<WillBeHeapHashSet<AtomicString> > m_tagNames;
     93     OwnPtrWillBeMember<WillBeHeapHashSet<AtomicString> > m_attributes;
     94 
     95     // If true, all descendants might be invalidated, so a full subtree recalc is required.
     96     unsigned m_allDescendantsMightBeInvalid : 1;
     97 
     98     // If true, all descendants which are custom pseudo elements must be invalidated.
     99     unsigned m_customPseudoInvalid : 1;
    100 
    101     // If true, the invalidation must traverse into ShadowRoots with this set.
    102     unsigned m_treeBoundaryCrossing : 1;
    103 };
    104 
    105 } // namespace blink
    106 
    107 #endif // DescendantInvalidationSet_h
    108