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 
20 namespace clang {
21   class ASTContext;
22   class Attr;
23 }
24 
25 // Defined in ASTContext.h
26 void *operator new(size_t Bytes, const clang::ASTContext &C,
27                    size_t Alignment = 8);
28 // FIXME: Being forced to not have a default argument here due to redeclaration
29 //        rules on default arguments sucks
30 void *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.
36 void operator delete(void *Ptr, const clang::ASTContext &C, size_t);
37 void operator delete[](void *Ptr, const clang::ASTContext &C, size_t);
38 
39 namespace clang {
40 
41 /// AttrVec - A vector of Attr, which is how they are stored on the AST.
42 typedef SmallVector<Attr*, 2> AttrVec;
43 typedef 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.
47 template <typename SpecificAttr, typename Container = AttrVec>
48 class 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 
AdvanceToNext()60   void AdvanceToNext() const {
61     while (!isa<SpecificAttr>(*Current))
62       ++Current;
63   }
64 
AdvanceToNext(Iterator I)65   void AdvanceToNext(Iterator I) const {
66     while (Current != I && !isa<SpecificAttr>(*Current))
67       ++Current;
68   }
69 
70 public:
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 
specific_attr_iterator()77   specific_attr_iterator() : Current() { }
specific_attr_iterator(Iterator i)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 == nullptr) == (Right.Current == nullptr));
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 
114 template <typename SpecificAttr, typename Container>
115 inline specific_attr_iterator<SpecificAttr, Container>
specific_attr_begin(const Container & container)116           specific_attr_begin(const Container& container) {
117   return specific_attr_iterator<SpecificAttr, Container>(container.begin());
118 }
119 template <typename SpecificAttr, typename Container>
120 inline specific_attr_iterator<SpecificAttr, Container>
specific_attr_end(const Container & container)121           specific_attr_end(const Container& container) {
122   return specific_attr_iterator<SpecificAttr, Container>(container.end());
123 }
124 
125 template <typename SpecificAttr, typename Container>
hasSpecificAttr(const Container & container)126 inline bool hasSpecificAttr(const Container& container) {
127   return specific_attr_begin<SpecificAttr>(container) !=
128           specific_attr_end<SpecificAttr>(container);
129 }
130 template <typename SpecificAttr, typename Container>
getSpecificAttr(const Container & container)131 inline 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 nullptr;
138 }
139 
140 }  // end namespace clang
141 
142 #endif
143