third_party/WebKit/Source/core/dom/NodeIterator.cpp

   1 /*
   2  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
   3  * Copyright (C) 2000 Frederik Holljen (frederik.holljen@hig.no)
   4  * Copyright (C) 2001 Peter Kelly (pmk@post.com)
   5  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
   6  * Copyright (C) 2004, 2008 Apple Inc. All rights reserved.
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Library General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Library General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Library General Public License
  19  * along with this library; see the file COPYING.LIB.  If not, write to
  20  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  21  * Boston, MA 02110-1301, USA.
  22  *
  23  */
  24
  25 #include "config.h"
  26 #include "core/dom/NodeIterator.h"
  27
  28 #include "bindings/core/v8/ExceptionState.h"
  29 #include "core/dom/Document.h"
  30 #include "core/dom/ExceptionCode.h"
  31 #include "core/dom/NodeTraversal.h"
  32
  33 namespace blink {
  34
  35 NodeIterator::NodePointer::NodePointer()
  36 {
  37 }
  38
  39 NodeIterator::NodePointer::NodePointer(PassRefPtrWillBeRawPtr<Node> n, bool b)
  40     : node(n)
  41     , isPointerBeforeNode(b)
  42 {
  43 }
  44
  45 void NodeIterator::NodePointer::clear()
  46 {
  47     node.clear();
  48 }
  49
  50 bool NodeIterator::NodePointer::moveToNext(Node* root)
  51 {
  52     if (!node)
  53         return false;
  54     if (isPointerBeforeNode) {
  55         isPointerBeforeNode = false;
  56         return true;
  57     }
  58     node = NodeTraversal::next(*node, root);
  59     return node;
  60 }
  61
  62 bool NodeIterator::NodePointer::moveToPrevious(Node* root)
  63 {
  64     if (!node)
  65         return false;
  66     if (!isPointerBeforeNode) {
  67         isPointerBeforeNode = true;
  68         return true;
  69     }
  70     node = NodeTraversal::previous(*node, root);
  71     return node;
  72 }
  73
  74 NodeIterator::NodeIterator(PassRefPtrWillBeRawPtr<Node> rootNode, unsigned whatToShow, PassRefPtrWillBeRawPtr<NodeFilter> filter)
  75     : NodeIteratorBase(rootNode, whatToShow, filter)
  76     , m_referenceNode(root(), true)
  77 {
  78     root()->document().attachNodeIterator(this);
  79 }
  80
  81 #if !ENABLE(OILPAN)
  82 NodeIterator::~NodeIterator()
  83 {
  84     root()->document().detachNodeIterator(this);
  85 }
  86 #endif
  87
  88 PassRefPtrWillBeRawPtr<Node> NodeIterator::nextNode(ExceptionState& exceptionState)
  89 {
  90     RefPtrWillBeRawPtr<Node> result = nullptr;
  91
  92     m_candidateNode = m_referenceNode;
  93     while (m_candidateNode.moveToNext(root())) {
  94         // NodeIterators treat the DOM tree as a flat list of nodes.
  95         // In other words, FILTER_REJECT does not pass over descendants
  96         // of the rejected node. Hence, FILTER_REJECT is the same as FILTER_SKIP.
  97         RefPtrWillBeRawPtr<Node> provisionalResult = m_candidateNode.node;
  98         bool nodeWasAccepted = acceptNode(provisionalResult.get(), exceptionState) == NodeFilter::FILTER_ACCEPT;
  99         if (exceptionState.hadException())
 100             break;
 101         if (nodeWasAccepted) {
 102             m_referenceNode = m_candidateNode;
 103             result = provisionalResult.release();
 104             break;
 105         }
 106     }
 107
 108     m_candidateNode.clear();
 109     return result.release();
 110 }
 111
 112 PassRefPtrWillBeRawPtr<Node> NodeIterator::previousNode(ExceptionState& exceptionState)
 113 {
 114     RefPtrWillBeRawPtr<Node> result = nullptr;
 115
 116     m_candidateNode = m_referenceNode;
 117     while (m_candidateNode.moveToPrevious(root())) {
 118         // NodeIterators treat the DOM tree as a flat list of nodes.
 119         // In other words, FILTER_REJECT does not pass over descendants
 120         // of the rejected node. Hence, FILTER_REJECT is the same as FILTER_SKIP.
 121         RefPtrWillBeRawPtr<Node> provisionalResult = m_candidateNode.node;
 122         bool nodeWasAccepted = acceptNode(provisionalResult.get(), exceptionState) == NodeFilter::FILTER_ACCEPT;
 123         if (exceptionState.hadException())
 124             break;
 125         if (nodeWasAccepted) {
 126             m_referenceNode = m_candidateNode;
 127             result = provisionalResult.release();
 128             break;
 129         }
 130     }
 131
 132     m_candidateNode.clear();
 133     return result.release();
 134 }
 135
 136 void NodeIterator::detach()
 137 {
 138     // This is now a no-op as per the DOM specification.
 139 }
 140
 141 void NodeIterator::nodeWillBeRemoved(Node& removedNode)
 142 {
 143     updateForNodeRemoval(removedNode, m_candidateNode);
 144     updateForNodeRemoval(removedNode, m_referenceNode);
 145 }
 146
 147 void NodeIterator::updateForNodeRemoval(Node& removedNode, NodePointer& referenceNode) const
 148 {
 149     ASSERT(root()->document() == removedNode.document());
 150
 151     // Iterator is not affected if the removed node is the reference node and is the root.
 152     // or if removed node is not the reference node, or the ancestor of the reference node.
 153     if (!removedNode.isDescendantOf(root()))
 154         return;
 155     bool willRemoveReferenceNode = removedNode == referenceNode.node.get();
 156     bool willRemoveReferenceNodeAncestor = referenceNode.node && referenceNode.node->isDescendantOf(&removedNode);
 157     if (!willRemoveReferenceNode && !willRemoveReferenceNodeAncestor)
 158         return;
 159
 160     if (referenceNode.isPointerBeforeNode) {
 161         Node* node = NodeTraversal::next(removedNode, root());
 162         if (node) {
 163             // Move out from under the node being removed if the new reference
 164             // node is a descendant of the node being removed.
 165             while (node && node->isDescendantOf(&removedNode))
 166                 node = NodeTraversal::next(*node, root());
 167             if (node)
 168                 referenceNode.node = node;
 169         } else {
 170             node = NodeTraversal::previous(removedNode, root());
 171             if (node) {
 172                 // Move out from under the node being removed if the reference node is
 173                 // a descendant of the node being removed.
 174                 if (willRemoveReferenceNodeAncestor) {
 175                     while (node && node->isDescendantOf(&removedNode))
 176                         node = NodeTraversal::previous(*node, root());
 177                 }
 178                 if (node) {
 179                     // Removing last node.
 180                     // Need to move the pointer after the node preceding the
 181                     // new reference node.
 182                     referenceNode.node = node;
 183                     referenceNode.isPointerBeforeNode = false;
 184                 }
 185             }
 186         }
 187     } else {
 188         Node* node = NodeTraversal::previous(removedNode, root());
 189         if (node) {
 190             // Move out from under the node being removed if the reference node is
 191             // a descendant of the node being removed.
 192             if (willRemoveReferenceNodeAncestor) {
 193                 while (node && node->isDescendantOf(&removedNode))
 194                     node = NodeTraversal::previous(*node, root());
 195             }
 196             if (node)
 197                 referenceNode.node = node;
 198         } else {
 199             // FIXME: This branch doesn't appear to have any LayoutTests.
 200             node = NodeTraversal::next(removedNode, root());
 201             // Move out from under the node being removed if the reference node is
 202             // a descendant of the node being removed.
 203             if (willRemoveReferenceNodeAncestor) {
 204                 while (node && node->isDescendantOf(&removedNode))
 205                     node = NodeTraversal::previous(*node, root());
 206             }
 207             if (node)
 208                 referenceNode.node = node;
 209         }
 210     }
 211 }
 212
 213 DEFINE_TRACE(NodeIterator)
 214 {
 215     visitor->trace(m_referenceNode);
 216     visitor->trace(m_candidateNode);
 217     NodeIteratorBase::trace(visitor);
 218 }
 219
 220 } // namespace blink