DeclFriend.h revision aa49a7d70e58dac2aeb40664ba16d2ea571b8c95 
1//===-- DeclFriend.h - Classes for C++ friend declarations -*- 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 section of the AST representing C++ friend
11// declarations.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CLANG_AST_DECLFRIEND_H
16#define LLVM_CLANG_AST_DECLFRIEND_H
17
18#include "clang/AST/DeclCXX.h"
19#include "llvm/Support/Compiler.h"
20
21namespace clang {
22
23/// FriendDecl - Represents the declaration of a friend entity,
24/// which can be a function, a type, or a templated function or type.
25//  For example:
26///
27/// @code
28/// template <typename T> class A {
29///   friend int foo(T);
30///   friend class B;
31///   friend T; // only in C++0x
32///   template <typename U> friend class C;
33///   template <typename U> friend A& operator+=(A&, const U&) { ... }
34/// };
35/// @endcode
36///
37/// The semantic context of a friend decl is its declaring class.
38class FriendDecl : public Decl {
39  virtual void anchor();
40public:
41  typedef llvm::PointerUnion<NamedDecl*,TypeSourceInfo*> FriendUnion;
42
43private:
44  // The declaration that's a friend of this class.
45  FriendUnion Friend;
46
47  // A pointer to the next friend in the sequence.
48  LazyDeclPtr NextFriend;
49
50  // Location of the 'friend' specifier.
51  SourceLocation FriendLoc;
52
53  /// True if this 'friend' declaration is unsupported.  Eventually we
54  /// will support every possible friend declaration, but for now we
55  /// silently ignore some and set this flag to authorize all access.
56  bool UnsupportedFriend;
57
58  friend class CXXRecordDecl::friend_iterator;
59  friend class CXXRecordDecl;
60
61  FriendDecl(DeclContext *DC, SourceLocation L, FriendUnion Friend,
62             SourceLocation FriendL)
63    : Decl(Decl::Friend, DC, L),
64      Friend(Friend),
65      NextFriend(),
66      FriendLoc(FriendL),
67      UnsupportedFriend(false) {
68  }
69
70  explicit FriendDecl(EmptyShell Empty)
71    : Decl(Decl::Friend, Empty), NextFriend() { }
72
73  FriendDecl *getNextFriend() {
74    return cast_or_null<FriendDecl>(
75                          NextFriend.get(getASTContext().getExternalSource()));
76  }
77
78public:
79  static FriendDecl *Create(ASTContext &C, DeclContext *DC,
80                            SourceLocation L, FriendUnion Friend_,
81                            SourceLocation FriendL);
82  static FriendDecl *CreateDeserialized(ASTContext &C, unsigned ID);
83
84  /// If this friend declaration names an (untemplated but possibly
85  /// dependent) type, return the type; otherwise return null.  This
86  /// is used for elaborated-type-specifiers and, in C++0x, for
87  /// arbitrary friend type declarations.
88  TypeSourceInfo *getFriendType() const {
89    return Friend.dyn_cast<TypeSourceInfo*>();
90  }
91
92  /// If this friend declaration doesn't name a type, return the inner
93  /// declaration.
94  NamedDecl *getFriendDecl() const {
95    return Friend.dyn_cast<NamedDecl*>();
96  }
97
98  /// Retrieves the location of the 'friend' keyword.
99  SourceLocation getFriendLoc() const {
100    return FriendLoc;
101  }
102
103  /// Retrieves the source range for the friend declaration.
104  SourceRange getSourceRange() const LLVM_READONLY {
105    /* FIXME: consider the case of templates wrt start of range. */
106    if (NamedDecl *ND = getFriendDecl())
107      return SourceRange(getFriendLoc(), ND->getLocEnd());
108    else if (TypeSourceInfo *TInfo = getFriendType())
109      return SourceRange(getFriendLoc(), TInfo->getTypeLoc().getEndLoc());
110    else
111      return SourceRange(getFriendLoc(), getLocation());
112  }
113
114  /// Determines if this friend kind is unsupported.
115  bool isUnsupportedFriend() const {
116    return UnsupportedFriend;
117  }
118  void setUnsupportedFriend(bool Unsupported) {
119    UnsupportedFriend = Unsupported;
120  }
121
122  // Implement isa/cast/dyncast/etc.
123  static bool classof(const Decl *D) { return classofKind(D->getKind()); }
124  static bool classof(const FriendDecl *D) { return true; }
125  static bool classofKind(Kind K) { return K == Decl::Friend; }
126
127  friend class ASTDeclReader;
128  friend class ASTDeclWriter;
129};
130
131/// An iterator over the friend declarations of a class.
132class CXXRecordDecl::friend_iterator {
133  FriendDecl *Ptr;
134
135  friend class CXXRecordDecl;
136  explicit friend_iterator(FriendDecl *Ptr) : Ptr(Ptr) {}
137public:
138  friend_iterator() {}
139
140  typedef FriendDecl *value_type;
141  typedef FriendDecl *reference;
142  typedef FriendDecl *pointer;
143  typedef int difference_type;
144  typedef std::forward_iterator_tag iterator_category;
145
146  reference operator*() const { return Ptr; }
147
148  friend_iterator &operator++() {
149    assert(Ptr && "attempt to increment past end of friend list");
150    Ptr = Ptr->getNextFriend();
151    return *this;
152  }
153
154  friend_iterator operator++(int) {
155    friend_iterator tmp = *this;
156    ++*this;
157    return tmp;
158  }
159
160  bool operator==(const friend_iterator &Other) const {
161    return Ptr == Other.Ptr;
162  }
163
164  bool operator!=(const friend_iterator &Other) const {
165    return Ptr != Other.Ptr;
166  }
167
168  friend_iterator &operator+=(difference_type N) {
169    assert(N >= 0 && "cannot rewind a CXXRecordDecl::friend_iterator");
170    while (N--)
171      ++*this;
172    return *this;
173  }
174
175  friend_iterator operator+(difference_type N) const {
176    friend_iterator tmp = *this;
177    tmp += N;
178    return tmp;
179  }
180};
181
182inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_begin() const {
183  return friend_iterator(data().FirstFriend);
184}
185
186inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_end() const {
187  return friend_iterator(0);
188}
189
190inline void CXXRecordDecl::pushFriendDecl(FriendDecl *FD) {
191  assert(FD->NextFriend == 0 && "friend already has next friend?");
192  FD->NextFriend = data().FirstFriend;
193  data().FirstFriend = FD;
194}
195
196}
197
198#endif
199