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 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 RenderLayerStackingNodeIterator_h 32 #define RenderLayerStackingNodeIterator_h 33 34 #include "wtf/Noncopyable.h" 35 36 namespace blink { 37 38 enum ChildrenIteration { 39 NegativeZOrderChildren = 1, 40 NormalFlowChildren = 1 << 1, 41 PositiveZOrderChildren = 1 << 2, 42 AllChildren = NegativeZOrderChildren | NormalFlowChildren | PositiveZOrderChildren 43 }; 44 45 class RenderLayerStackingNode; 46 47 // This iterator walks the RenderLayerStackingNode lists in the following order: 48 // NegativeZOrderChildren -> NormalFlowChildren -> PositiveZOrderChildren. 49 class RenderLayerStackingNodeIterator { 50 WTF_MAKE_NONCOPYABLE(RenderLayerStackingNodeIterator); 51 public: RenderLayerStackingNodeIterator(const RenderLayerStackingNode & root,unsigned whichChildren)52 RenderLayerStackingNodeIterator(const RenderLayerStackingNode& root, unsigned whichChildren) 53 : m_root(root) 54 , m_remainingChildren(whichChildren) 55 , m_index(0) 56 { 57 } 58 59 RenderLayerStackingNode* next(); 60 61 private: 62 const RenderLayerStackingNode& m_root; 63 unsigned m_remainingChildren; 64 unsigned m_index; 65 }; 66 67 // This iterator is similar to RenderLayerStackingNodeIterator but it walks the lists in reverse order 68 // (from the last item to the first one). 69 class RenderLayerStackingNodeReverseIterator { 70 WTF_MAKE_NONCOPYABLE(RenderLayerStackingNodeReverseIterator); 71 public: RenderLayerStackingNodeReverseIterator(const RenderLayerStackingNode & root,unsigned whichChildren)72 RenderLayerStackingNodeReverseIterator(const RenderLayerStackingNode& root, unsigned whichChildren) 73 : m_root(root) 74 , m_remainingChildren(whichChildren) 75 { 76 setIndexToLastItem(); 77 } 78 79 RenderLayerStackingNode* next(); 80 81 private: 82 void setIndexToLastItem(); 83 84 const RenderLayerStackingNode& m_root; 85 unsigned m_remainingChildren; 86 int m_index; 87 }; 88 89 } // namespace blink 90 91 #endif // RenderLayerStackingNodeIterator_h 92