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