AttrIterator.h revision 651f13cea278ec967336033dd032faef0e9fc2ec 
1//===--- AttrIterator.h - Classes for attribute iteration -------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file defines the Attr vector and specific_attr_iterator interfaces.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_AST_ATTRITERATOR_H
15#define LLVM_CLANG_AST_ATTRITERATOR_H
16
17#include "clang/Basic/LLVM.h"
18#include <iterator>
19
20namespace clang {
21  class ASTContext;
22  class Attr;
23}
24
25// Defined in ASTContext.h
26void *operator new(size_t Bytes, const clang::ASTContext &C,
27                   size_t Alignment = 16);
28// FIXME: Being forced to not have a default argument here due to redeclaration
29//        rules on default arguments sucks
30void *operator new[](size_t Bytes, const clang::ASTContext &C,
31                     size_t Alignment);
32
33// It is good practice to pair new/delete operators.  Also, MSVC gives many
34// warnings if a matching delete overload is not declared, even though the
35// throw() spec guarantees it will not be implicitly called.
36void operator delete(void *Ptr, const clang::ASTContext &C, size_t);
37void operator delete[](void *Ptr, const clang::ASTContext &C, size_t);
38
39namespace clang {
40
41/// AttrVec - A vector of Attr, which is how they are stored on the AST.
42typedef SmallVector<Attr*, 2> AttrVec;
43typedef SmallVector<const Attr*, 2> ConstAttrVec;
44
45/// specific_attr_iterator - Iterates over a subrange of an AttrVec, only
46/// providing attributes that are of a specific type.
47template <typename SpecificAttr, typename Container = AttrVec>
48class specific_attr_iterator {
49  typedef typename Container::const_iterator Iterator;
50
51  /// Current - The current, underlying iterator.
52  /// In order to ensure we don't dereference an invalid iterator unless
53  /// specifically requested, we don't necessarily advance this all the
54  /// way. Instead, we advance it when an operation is requested; if the
55  /// operation is acting on what should be a past-the-end iterator,
56  /// then we offer no guarantees, but this way we do not dereference a
57  /// past-the-end iterator when we move to a past-the-end position.
58  mutable Iterator Current;
59
60  void AdvanceToNext() const {
61    while (!isa<SpecificAttr>(*Current))
62      ++Current;
63  }
64
65  void AdvanceToNext(Iterator I) const {
66    while (Current != I && !isa<SpecificAttr>(*Current))
67      ++Current;
68  }
69
70public:
71  typedef SpecificAttr*             value_type;
72  typedef SpecificAttr*             reference;
73  typedef SpecificAttr*             pointer;
74  typedef std::forward_iterator_tag iterator_category;
75  typedef std::ptrdiff_t            difference_type;
76
77  specific_attr_iterator() : Current() { }
78  explicit specific_attr_iterator(Iterator i) : Current(i) { }
79
80  reference operator*() const {
81    AdvanceToNext();
82    return cast<SpecificAttr>(*Current);
83  }
84  pointer operator->() const {
85    AdvanceToNext();
86    return cast<SpecificAttr>(*Current);
87  }
88
89  specific_attr_iterator& operator++() {
90    ++Current;
91    return *this;
92  }
93  specific_attr_iterator operator++(int) {
94    specific_attr_iterator Tmp(*this);
95    ++(*this);
96    return Tmp;
97  }
98
99  friend bool operator==(specific_attr_iterator Left,
100                         specific_attr_iterator Right) {
101    assert((Left.Current == 0) == (Right.Current == 0));
102    if (Left.Current < Right.Current)
103      Left.AdvanceToNext(Right.Current);
104    else
105      Right.AdvanceToNext(Left.Current);
106    return Left.Current == Right.Current;
107  }
108  friend bool operator!=(specific_attr_iterator Left,
109                         specific_attr_iterator Right) {
110    return !(Left == Right);
111  }
112};
113
114template <typename SpecificAttr, typename Container>
115inline specific_attr_iterator<SpecificAttr, Container>
116          specific_attr_begin(const Container& container) {
117  return specific_attr_iterator<SpecificAttr, Container>(container.begin());
118}
119template <typename SpecificAttr, typename Container>
120inline specific_attr_iterator<SpecificAttr, Container>
121          specific_attr_end(const Container& container) {
122  return specific_attr_iterator<SpecificAttr, Container>(container.end());
123}
124
125template <typename SpecificAttr, typename Container>
126inline bool hasSpecificAttr(const Container& container) {
127  return specific_attr_begin<SpecificAttr>(container) !=
128          specific_attr_end<SpecificAttr>(container);
129}
130template <typename SpecificAttr, typename Container>
131inline SpecificAttr *getSpecificAttr(const Container& container) {
132  specific_attr_iterator<SpecificAttr, Container> i =
133      specific_attr_begin<SpecificAttr>(container);
134  if (i != specific_attr_end<SpecificAttr>(container))
135    return *i;
136  else
137    return 0;
138}
139
140}  // end namespace clang
141
142#endif
143