1 //===- AttrIterator.h - Classes for attribute iteration ---------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines the Attr vector and specific_attr_iterator interfaces.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #ifndef LLVM_CLANG_AST_ATTRITERATOR_H
14 #define LLVM_CLANG_AST_ATTRITERATOR_H
15
16 #include "clang/Basic/LLVM.h"
17 #include "llvm/ADT/SmallVector.h"
18 #include "llvm/Support/Casting.h"
19 #include <cassert>
20 #include <cstddef>
21 #include <iterator>
22
23 namespace clang {
24
25 class Attr;
26
27 /// AttrVec - A vector of Attr, which is how they are stored on the AST.
28 using AttrVec = SmallVector<Attr *, 4>;
29
30 /// specific_attr_iterator - Iterates over a subrange of an AttrVec, only
31 /// providing attributes that are of a specific type.
32 template <typename SpecificAttr, typename Container = AttrVec>
33 class specific_attr_iterator {
34 using Iterator = typename Container::const_iterator;
35
36 /// Current - The current, underlying iterator.
37 /// In order to ensure we don't dereference an invalid iterator unless
38 /// specifically requested, we don't necessarily advance this all the
39 /// way. Instead, we advance it when an operation is requested; if the
40 /// operation is acting on what should be a past-the-end iterator,
41 /// then we offer no guarantees, but this way we do not dereference a
42 /// past-the-end iterator when we move to a past-the-end position.
43 mutable Iterator Current;
44
AdvanceToNext()45 void AdvanceToNext() const {
46 while (!isa<SpecificAttr>(*Current))
47 ++Current;
48 }
49
AdvanceToNext(Iterator I)50 void AdvanceToNext(Iterator I) const {
51 while (Current != I && !isa<SpecificAttr>(*Current))
52 ++Current;
53 }
54
55 public:
56 using value_type = SpecificAttr *;
57 using reference = SpecificAttr *;
58 using pointer = SpecificAttr *;
59 using iterator_category = std::forward_iterator_tag;
60 using difference_type = std::ptrdiff_t;
61
62 specific_attr_iterator() = default;
specific_attr_iterator(Iterator i)63 explicit specific_attr_iterator(Iterator i) : Current(i) {}
64
65 reference operator*() const {
66 AdvanceToNext();
67 return cast<SpecificAttr>(*Current);
68 }
69 pointer operator->() const {
70 AdvanceToNext();
71 return cast<SpecificAttr>(*Current);
72 }
73
74 specific_attr_iterator& operator++() {
75 ++Current;
76 return *this;
77 }
78 specific_attr_iterator operator++(int) {
79 specific_attr_iterator Tmp(*this);
80 ++(*this);
81 return Tmp;
82 }
83
84 friend bool operator==(specific_attr_iterator Left,
85 specific_attr_iterator Right) {
86 assert((Left.Current == nullptr) == (Right.Current == nullptr));
87 if (Left.Current < Right.Current)
88 Left.AdvanceToNext(Right.Current);
89 else
90 Right.AdvanceToNext(Left.Current);
91 return Left.Current == Right.Current;
92 }
93 friend bool operator!=(specific_attr_iterator Left,
94 specific_attr_iterator Right) {
95 return !(Left == Right);
96 }
97 };
98
99 template <typename SpecificAttr, typename Container>
100 inline specific_attr_iterator<SpecificAttr, Container>
specific_attr_begin(const Container & container)101 specific_attr_begin(const Container& container) {
102 return specific_attr_iterator<SpecificAttr, Container>(container.begin());
103 }
104 template <typename SpecificAttr, typename Container>
105 inline specific_attr_iterator<SpecificAttr, Container>
specific_attr_end(const Container & container)106 specific_attr_end(const Container& container) {
107 return specific_attr_iterator<SpecificAttr, Container>(container.end());
108 }
109
110 template <typename SpecificAttr, typename Container>
hasSpecificAttr(const Container & container)111 inline bool hasSpecificAttr(const Container& container) {
112 return specific_attr_begin<SpecificAttr>(container) !=
113 specific_attr_end<SpecificAttr>(container);
114 }
115 template <typename SpecificAttr, typename Container>
getSpecificAttr(const Container & container)116 inline SpecificAttr *getSpecificAttr(const Container& container) {
117 specific_attr_iterator<SpecificAttr, Container> i =
118 specific_attr_begin<SpecificAttr>(container);
119 if (i != specific_attr_end<SpecificAttr>(container))
120 return *i;
121 else
122 return nullptr;
123 }
124
125 } // namespace clang
126
127 #endif // LLVM_CLANG_AST_ATTRITERATOR_H
128