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 "llvm/ADT/SmallVector.h"
19 #include "llvm/Support/Casting.h"
20 #include <cassert>
21 #include <cstddef>
22 #include <iterator>
23
24 namespace clang {
25
26 class ASTContext;
27 class Attr;
28
29 /// AttrVec - A vector of Attr, which is how they are stored on the AST.
30 using AttrVec = SmallVector<Attr *, 4>;
31
32 /// specific_attr_iterator - Iterates over a subrange of an AttrVec, only
33 /// providing attributes that are of a specific type.
34 template <typename SpecificAttr, typename Container = AttrVec>
35 class specific_attr_iterator {
36 using Iterator = typename Container::const_iterator;
37
38 /// Current - The current, underlying iterator.
39 /// In order to ensure we don't dereference an invalid iterator unless
40 /// specifically requested, we don't necessarily advance this all the
41 /// way. Instead, we advance it when an operation is requested; if the
42 /// operation is acting on what should be a past-the-end iterator,
43 /// then we offer no guarantees, but this way we do not dereference a
44 /// past-the-end iterator when we move to a past-the-end position.
45 mutable Iterator Current;
46
AdvanceToNext()47 void AdvanceToNext() const {
48 while (!isa<SpecificAttr>(*Current))
49 ++Current;
50 }
51
AdvanceToNext(Iterator I)52 void AdvanceToNext(Iterator I) const {
53 while (Current != I && !isa<SpecificAttr>(*Current))
54 ++Current;
55 }
56
57 public:
58 using value_type = SpecificAttr *;
59 using reference = SpecificAttr *;
60 using pointer = SpecificAttr *;
61 using iterator_category = std::forward_iterator_tag;
62 using difference_type = std::ptrdiff_t;
63
64 specific_attr_iterator() = default;
specific_attr_iterator(Iterator i)65 explicit specific_attr_iterator(Iterator i) : Current(i) {}
66
67 reference operator*() const {
68 AdvanceToNext();
69 return cast<SpecificAttr>(*Current);
70 }
71 pointer operator->() const {
72 AdvanceToNext();
73 return cast<SpecificAttr>(*Current);
74 }
75
76 specific_attr_iterator& operator++() {
77 ++Current;
78 return *this;
79 }
80 specific_attr_iterator operator++(int) {
81 specific_attr_iterator Tmp(*this);
82 ++(*this);
83 return Tmp;
84 }
85
86 friend bool operator==(specific_attr_iterator Left,
87 specific_attr_iterator Right) {
88 assert((Left.Current == nullptr) == (Right.Current == nullptr));
89 if (Left.Current < Right.Current)
90 Left.AdvanceToNext(Right.Current);
91 else
92 Right.AdvanceToNext(Left.Current);
93 return Left.Current == Right.Current;
94 }
95 friend bool operator!=(specific_attr_iterator Left,
96 specific_attr_iterator Right) {
97 return !(Left == Right);
98 }
99 };
100
101 template <typename SpecificAttr, typename Container>
102 inline specific_attr_iterator<SpecificAttr, Container>
specific_attr_begin(const Container & container)103 specific_attr_begin(const Container& container) {
104 return specific_attr_iterator<SpecificAttr, Container>(container.begin());
105 }
106 template <typename SpecificAttr, typename Container>
107 inline specific_attr_iterator<SpecificAttr, Container>
specific_attr_end(const Container & container)108 specific_attr_end(const Container& container) {
109 return specific_attr_iterator<SpecificAttr, Container>(container.end());
110 }
111
112 template <typename SpecificAttr, typename Container>
hasSpecificAttr(const Container & container)113 inline bool hasSpecificAttr(const Container& container) {
114 return specific_attr_begin<SpecificAttr>(container) !=
115 specific_attr_end<SpecificAttr>(container);
116 }
117 template <typename SpecificAttr, typename Container>
getSpecificAttr(const Container & container)118 inline SpecificAttr *getSpecificAttr(const Container& container) {
119 specific_attr_iterator<SpecificAttr, Container> i =
120 specific_attr_begin<SpecificAttr>(container);
121 if (i != specific_attr_end<SpecificAttr>(container))
122 return *i;
123 else
124 return nullptr;
125 }
126
127 } // namespace clang
128
129 #endif // LLVM_CLANG_AST_ATTRITERATOR_H
130