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 WebCore { 37 38 enum ChildrenIteration { 39 NegativeZOrderChildren = 1, 40 NormalFlowChildren = 1 << 1, 41 PositiveZOrderChildren = 1 << 2, 42 AllChildren = NegativeZOrderChildren | NormalFlowChildren | PositiveZOrderChildren 43 }; 44 45 class RenderLayer; 46 class RenderLayerStackingNode; 47 48 // This iterator walks the RenderLayerStackingNode lists in the following order: 49 // NegativeZOrderChildren -> NormalFlowChildren -> PositiveZOrderChildren. 50 class RenderLayerStackingNodeIterator { 51 WTF_MAKE_NONCOPYABLE(RenderLayerStackingNodeIterator); 52 public: RenderLayerStackingNodeIterator(const RenderLayerStackingNode & root,unsigned whichChildren)53 RenderLayerStackingNodeIterator(const RenderLayerStackingNode& root, unsigned whichChildren) 54 : m_root(root) 55 , m_remainingChildren(whichChildren) 56 , m_index(0) 57 { 58 } 59 60 RenderLayerStackingNode* next(); 61 62 private: 63 const RenderLayerStackingNode& m_root; 64 unsigned m_remainingChildren; 65 unsigned m_index; 66 }; 67 68 // This iterator is similar to RenderLayerStackingNodeIterator but it walks the lists in reverse order 69 // (from the last item to the first one). 70 class RenderLayerStackingNodeReverseIterator { 71 WTF_MAKE_NONCOPYABLE(RenderLayerStackingNodeReverseIterator); 72 public: RenderLayerStackingNodeReverseIterator(const RenderLayerStackingNode & root,unsigned whichChildren)73 RenderLayerStackingNodeReverseIterator(const RenderLayerStackingNode& root, unsigned whichChildren) 74 : m_root(root) 75 , m_remainingChildren(whichChildren) 76 { 77 setIndexToLastItem(); 78 } 79 80 RenderLayerStackingNode* next(); 81 82 private: 83 void setIndexToLastItem(); 84 85 const RenderLayerStackingNode& m_root; 86 unsigned m_remainingChildren; 87 int m_index; 88 }; 89 90 } // namespace WebCore 91 92 #endif // RenderLayerStackingNodeIterator_h 93