1 /*
2 * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26 #include "config.h"
27
28 #if ENABLE(XPATH)
29 #include "XPathNodeSet.h"
30
31 #include "Attr.h"
32 #include "Element.h"
33 #include "Node.h"
34
35 namespace WebCore {
36 namespace XPath {
37
parentWithDepth(unsigned depth,const Vector<Node * > & parents)38 static inline Node* parentWithDepth(unsigned depth, const Vector<Node*>& parents)
39 {
40 ASSERT(parents.size() >= depth + 1);
41 return parents[parents.size() - 1 - depth];
42 }
43
sortBlock(unsigned from,unsigned to,Vector<Vector<Node * >> & parentMatrix,bool mayContainAttributeNodes)44 static void sortBlock(unsigned from, unsigned to, Vector<Vector<Node*> >& parentMatrix, bool mayContainAttributeNodes)
45 {
46 ASSERT(from + 1 < to); // Should not call this function with less that two nodes to sort.
47 unsigned minDepth = UINT_MAX;
48 for (unsigned i = from; i < to; ++i) {
49 unsigned depth = parentMatrix[i].size() - 1;
50 if (minDepth > depth)
51 minDepth = depth;
52 }
53
54 // Find the common ancestor.
55 unsigned commonAncestorDepth = minDepth;
56 Node* commonAncestor;
57 while (true) {
58 commonAncestor = parentWithDepth(commonAncestorDepth, parentMatrix[from]);
59 if (commonAncestorDepth == 0)
60 break;
61
62 bool allEqual = true;
63 for (unsigned i = from + 1; i < to; ++i) {
64 if (commonAncestor != parentWithDepth(commonAncestorDepth, parentMatrix[i])) {
65 allEqual = false;
66 break;
67 }
68 }
69 if (allEqual)
70 break;
71
72 --commonAncestorDepth;
73 }
74
75 if (commonAncestorDepth == minDepth) {
76 // One of the nodes is the common ancestor => it is the first in document order.
77 // Find it and move it to the beginning.
78 for (unsigned i = from; i < to; ++i)
79 if (commonAncestor == parentMatrix[i][0]) {
80 parentMatrix[i].swap(parentMatrix[from]);
81 if (from + 2 < to)
82 sortBlock(from + 1, to, parentMatrix, mayContainAttributeNodes);
83 return;
84 }
85 }
86
87 if (mayContainAttributeNodes && commonAncestor->isElementNode()) {
88 // The attribute nodes and namespace nodes of an element occur before the children of the element.
89 // The namespace nodes are defined to occur before the attribute nodes.
90 // The relative order of namespace nodes is implementation-dependent.
91 // The relative order of attribute nodes is implementation-dependent.
92 unsigned sortedEnd = from;
93 // FIXME: namespace nodes are not implemented.
94 for (unsigned i = sortedEnd; i < to; ++i) {
95 Node* n = parentMatrix[i][0];
96 if (n->isAttributeNode() && static_cast<Attr*>(n)->ownerElement() == commonAncestor)
97 parentMatrix[i].swap(parentMatrix[sortedEnd++]);
98 }
99 if (sortedEnd != from) {
100 if (to - sortedEnd > 1)
101 sortBlock(sortedEnd, to, parentMatrix, mayContainAttributeNodes);
102 return;
103 }
104 }
105
106 // Children nodes of the common ancestor induce a subdivision of our node-set.
107 // Sort it according to this subdivision, and recursively sort each group.
108 HashSet<Node*> parentNodes;
109 for (unsigned i = from; i < to; ++i)
110 parentNodes.add(parentWithDepth(commonAncestorDepth + 1, parentMatrix[i]));
111
112 unsigned previousGroupEnd = from;
113 unsigned groupEnd = from;
114 for (Node* n = commonAncestor->firstChild(); n; n = n->nextSibling()) {
115 // If parentNodes contains the node, perform a linear search to move its children in the node-set to the beginning.
116 if (parentNodes.contains(n)) {
117 for (unsigned i = groupEnd; i < to; ++i)
118 if (parentWithDepth(commonAncestorDepth + 1, parentMatrix[i]) == n)
119 parentMatrix[i].swap(parentMatrix[groupEnd++]);
120
121 if (groupEnd - previousGroupEnd > 1)
122 sortBlock(previousGroupEnd, groupEnd, parentMatrix, mayContainAttributeNodes);
123
124 ASSERT(previousGroupEnd != groupEnd);
125 previousGroupEnd = groupEnd;
126 #ifndef NDEBUG
127 parentNodes.remove(n);
128 #endif
129 }
130 }
131
132 ASSERT(parentNodes.isEmpty());
133 }
134
sort() const135 void NodeSet::sort() const
136 {
137 if (m_isSorted)
138 return;
139
140 unsigned nodeCount = m_nodes.size();
141 if (nodeCount < 2) {
142 const_cast<bool&>(m_isSorted) = true;
143 return;
144 }
145
146 bool containsAttributeNodes = false;
147
148 Vector<Vector<Node*> > parentMatrix(nodeCount);
149 for (unsigned i = 0; i < nodeCount; ++i) {
150 Vector<Node*>& parentsVector = parentMatrix[i];
151 Node* n = m_nodes[i].get();
152 parentsVector.append(n);
153 if (n->isAttributeNode()) {
154 n = static_cast<Attr*>(n)->ownerElement();
155 parentsVector.append(n);
156 containsAttributeNodes = true;
157 }
158 while ((n = n->parentNode()))
159 parentsVector.append(n);
160 }
161 sortBlock(0, nodeCount, parentMatrix, containsAttributeNodes);
162
163 // It is not possible to just assign the result to m_nodes, because some nodes may get dereferenced and destroyed.
164 Vector<RefPtr<Node> > sortedNodes;
165 sortedNodes.reserveInitialCapacity(nodeCount);
166 for (unsigned i = 0; i < nodeCount; ++i)
167 sortedNodes.append(parentMatrix[i][0]);
168
169 const_cast<Vector<RefPtr<Node> >& >(m_nodes).swap(sortedNodes);
170 }
171
reverse()172 void NodeSet::reverse()
173 {
174 if (m_nodes.isEmpty())
175 return;
176
177 unsigned from = 0;
178 unsigned to = m_nodes.size() - 1;
179 while (from < to) {
180 m_nodes[from].swap(m_nodes[to]);
181 ++from;
182 --to;
183 }
184 }
185
firstNode() const186 Node* NodeSet::firstNode() const
187 {
188 if (isEmpty())
189 return 0;
190
191 sort(); // FIXME: fully sorting the node-set just to find its first node is wasteful.
192 return m_nodes.at(0).get();
193 }
194
anyNode() const195 Node* NodeSet::anyNode() const
196 {
197 if (isEmpty())
198 return 0;
199
200 return m_nodes.at(0).get();
201 }
202
203 }
204 }
205
206 #endif // ENABLE(XPATH)
207