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1 /*
2  * Copyright (C) 2014 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 #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 WebCore {
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:
create()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();
wholeSubtreeInvalid()65     bool wholeSubtreeInvalid() const { return m_allDescendantsMightBeInvalid; }
66 
setTreeBoundaryCrossing()67     void setTreeBoundaryCrossing() { m_treeBoundaryCrossing = true; }
treeBoundaryCrossing()68     bool treeBoundaryCrossing() const { return m_treeBoundaryCrossing; }
69 
setCustomPseudoInvalid()70     void setCustomPseudoInvalid() { m_customPseudoInvalid = true; }
customPseudoInvalid()71     bool customPseudoInvalid() const { return m_customPseudoInvalid; }
72 
isEmpty()73     bool isEmpty() const { return !m_classes && !m_ids && !m_tagNames && !m_attributes; }
74 
75     void trace(Visitor*);
76 
77 private:
78     DescendantInvalidationSet();
79 
80     WillBeHeapHashSet<AtomicString>& ensureClassSet();
81     WillBeHeapHashSet<AtomicString>& ensureIdSet();
82     WillBeHeapHashSet<AtomicString>& ensureTagNameSet();
83     WillBeHeapHashSet<AtomicString>& ensureAttributeSet();
84 
85     // FIXME: optimize this if it becomes a memory issue.
86     OwnPtrWillBeMember<WillBeHeapHashSet<AtomicString> > m_classes;
87     OwnPtrWillBeMember<WillBeHeapHashSet<AtomicString> > m_ids;
88     OwnPtrWillBeMember<WillBeHeapHashSet<AtomicString> > m_tagNames;
89     OwnPtrWillBeMember<WillBeHeapHashSet<AtomicString> > m_attributes;
90 
91     // If true, all descendants might be invalidated, so a full subtree recalc is required.
92     unsigned m_allDescendantsMightBeInvalid : 1;
93 
94     // If true, all descendants which are custom pseudo elements must be invalidated.
95     unsigned m_customPseudoInvalid : 1;
96 
97     // If true, the invalidation must traverse into ShadowRoots with this set.
98     unsigned m_treeBoundaryCrossing : 1;
99 };
100 
101 } // namespace WebCore
102 
103 #endif // DescendantInvalidationSet_h
104