third_party/WebKit/Source/core/xml/XPathStep.h

   1 /*
   2  * Copyright (C) 2005 Frerich Raabe <raabe@kde.org>
   3  * Copyright (C) 2006, 2009 Apple Inc.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #ifndef XPathStep_h
  28 #define XPathStep_h
  29
  30 #include "core/xml/XPathExpressionNode.h"
  31 #include "core/xml/XPathNodeSet.h"
  32
  33 namespace blink {
  34
  35 class Node;
  36
  37 namespace XPath {
  38
  39 class Predicate;
  40
  41 class Step final : public ParseNode {
  42     WTF_MAKE_NONCOPYABLE(Step);
  43 public:
  44     enum Axis {
  45         AncestorAxis, AncestorOrSelfAxis, AttributeAxis,
  46         ChildAxis, DescendantAxis, DescendantOrSelfAxis,
  47         FollowingAxis, FollowingSiblingAxis, NamespaceAxis,
  48         ParentAxis, PrecedingAxis, PrecedingSiblingAxis,
  49         SelfAxis
  50     };
  51
  52     class NodeTest : public GarbageCollectedFinalized<NodeTest> {
  53     public:
  54         enum Kind {
  55             TextNodeTest, CommentNodeTest, ProcessingInstructionNodeTest, AnyNodeTest, NameTest
  56         };
  57
  58         NodeTest(Kind kind) : m_kind(kind) { }
  59         NodeTest(Kind kind, const String& data) : m_kind(kind), m_data(data) { }
  60         NodeTest(Kind kind, const AtomicString& data, const AtomicString& namespaceURI) : m_kind(kind), m_data(data), m_namespaceURI(namespaceURI) { }
  61
  62         NodeTest(const NodeTest& o)
  63             : m_kind(o.m_kind)
  64             , m_data(o.m_data)
  65             , m_namespaceURI(o.m_namespaceURI)
  66         {
  67             ASSERT(o.m_mergedPredicates.isEmpty());
  68         }
  69         NodeTest& operator=(const NodeTest& o)
  70         {
  71             m_kind = o.m_kind;
  72             m_data = o.m_data;
  73             m_namespaceURI = o.m_namespaceURI;
  74             ASSERT(o.m_mergedPredicates.isEmpty());
  75             return *this;
  76         }
  77         DEFINE_INLINE_TRACE() { visitor->trace(m_mergedPredicates); }
  78
  79         Kind kind() const { return m_kind; }
  80         const AtomicString& data() const { return m_data; }
  81         const AtomicString& namespaceURI() const { return m_namespaceURI; }
  82         HeapVector<Member<Predicate>>& mergedPredicates() { return m_mergedPredicates; }
  83         const HeapVector<Member<Predicate>>& mergedPredicates() const { return m_mergedPredicates; }
  84
  85     private:
  86         Kind m_kind;
  87         AtomicString m_data;
  88         AtomicString m_namespaceURI;
  89
  90         // When possible, we merge some or all predicates with node test for better performance.
  91         HeapVector<Member<Predicate>> m_mergedPredicates;
  92     };
  93
  94     Step(Axis, const NodeTest&);
  95     Step(Axis, const NodeTest&, HeapVector<Member<Predicate>>&);
  96     ~Step() override;
  97     DECLARE_VIRTUAL_TRACE();
  98
  99     void optimize();
 100
 101     void evaluate(EvaluationContext&, Node* context, NodeSet&) const;
 102
 103     Axis axis() const { return m_axis; }
 104     const NodeTest& nodeTest() const { return *m_nodeTest; }
 105
 106 private:
 107     friend bool optimizeStepPair(Step*, Step*);
 108     bool predicatesAreContextListInsensitive() const;
 109     NodeTest& nodeTest() { return *m_nodeTest; }
 110
 111     void parseNodeTest(const String&);
 112     void nodesInAxis(EvaluationContext&, Node* context, NodeSet&) const;
 113     String namespaceFromNodetest(const String& nodeTest) const;
 114
 115     Axis m_axis;
 116     Member<NodeTest> m_nodeTest;
 117     HeapVector<Member<Predicate>> m_predicates;
 118 };
 119
 120 bool optimizeStepPair(Step*, Step*);
 121
 122 } // namespace XPath
 123
 124 } // namespace blink
 125
 126 #endif // XPathStep_h