third_party/WebKit/Source/core/paint/DeprecatedPaintLayerStackingNodeIterator.h

   1 /*
   2  * Copyright (C) 2013 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
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   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
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  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #ifndef DeprecatedPaintLayerStackingNodeIterator_h
  32 #define DeprecatedPaintLayerStackingNodeIterator_h
  33
  34 #include "wtf/Allocator.h"
  35 #include "wtf/Noncopyable.h"
  36
  37 namespace blink {
  38
  39 enum ChildrenIteration {
  40     NegativeZOrderChildren = 1,
  41     // Normal flow children are not mandated by CSS 2.1 but are an artifact of
  42     // our implementation: we allocate DeprecatedPaintLayers for elements that
  43     // are not treated as stacking contexts and thus we need to walk them
  44     // during painting and hit-testing.
  45     NormalFlowChildren = 1 << 1,
  46     PositiveZOrderChildren = 1 << 2,
  47     AllChildren = NegativeZOrderChildren | NormalFlowChildren | PositiveZOrderChildren
  48 };
  49
  50 class DeprecatedPaintLayerStackingNode;
  51 class DeprecatedPaintLayer;
  52
  53 // This iterator walks the DeprecatedPaintLayerStackingNode lists in the following order:
  54 // NegativeZOrderChildren -> NormalFlowChildren -> PositiveZOrderChildren.
  55 class DeprecatedPaintLayerStackingNodeIterator {
  56     STACK_ALLOCATED();
  57     WTF_MAKE_NONCOPYABLE(DeprecatedPaintLayerStackingNodeIterator);
  58 public:
  59     DeprecatedPaintLayerStackingNodeIterator(const DeprecatedPaintLayerStackingNode& root, unsigned whichChildren);
  60
  61     DeprecatedPaintLayerStackingNode* next();
  62
  63 private:
  64     const DeprecatedPaintLayerStackingNode& m_root;
  65     unsigned m_remainingChildren;
  66     unsigned m_index;
  67     DeprecatedPaintLayer* m_currentNormalFlowChild;
  68 };
  69
  70 // This iterator is similar to DeprecatedPaintLayerStackingNodeIterator but it walks the lists in reverse order
  71 // (from the last item to the first one).
  72 class DeprecatedPaintLayerStackingNodeReverseIterator {
  73     STACK_ALLOCATED();
  74     WTF_MAKE_NONCOPYABLE(DeprecatedPaintLayerStackingNodeReverseIterator);
  75 public:
  76     DeprecatedPaintLayerStackingNodeReverseIterator(const DeprecatedPaintLayerStackingNode& root, unsigned whichChildren)
  77         : m_root(root)
  78         , m_remainingChildren(whichChildren)
  79     {
  80         setIndexToLastItem();
  81     }
  82
  83     DeprecatedPaintLayerStackingNode* next();
  84
  85 private:
  86     void setIndexToLastItem();
  87
  88     const DeprecatedPaintLayerStackingNode& m_root;
  89     unsigned m_remainingChildren;
  90     int m_index;
  91     DeprecatedPaintLayer* m_currentNormalFlowChild;
  92 };
  93
  94 } // namespace blink
  95
  96 #endif // DeprecatedPaintLayerStackingNodeIterator_h