DeclFriend.h revision d6f80daa84164ceeb8900da07f43b6a150edf713 
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    if (!NextFriend.isOffset())
75      return cast_or_null<FriendDecl>(NextFriend.get(0));
76    return getNextFriendSlowCase();
77  }
78  FriendDecl *getNextFriendSlowCase();
79
80public:
81  static FriendDecl *Create(ASTContext &C, DeclContext *DC,
82                            SourceLocation L, FriendUnion Friend_,
83                            SourceLocation FriendL);
84  static FriendDecl *CreateDeserialized(ASTContext &C, unsigned ID);
85
86  /// If this friend declaration names an (untemplated but possibly
87  /// dependent) type, return the type; otherwise return null.  This
88  /// is used for elaborated-type-specifiers and, in C++0x, for
89  /// arbitrary friend type declarations.
90  TypeSourceInfo *getFriendType() const {
91    return Friend.dyn_cast<TypeSourceInfo*>();
92  }
93
94  /// If this friend declaration doesn't name a type, return the inner
95  /// declaration.
96  NamedDecl *getFriendDecl() const {
97    return Friend.dyn_cast<NamedDecl*>();
98  }
99
100  /// Retrieves the location of the 'friend' keyword.
101  SourceLocation getFriendLoc() const {
102    return FriendLoc;
103  }
104
105  /// Retrieves the source range for the friend declaration.
106  SourceRange getSourceRange() const LLVM_READONLY {
107    // FIXME: If this is a friend function declaration, the 'friend' keyword
108    // might not be the first token of the declaration.
109    if (NamedDecl *ND = getFriendDecl())
110      return SourceRange(getFriendLoc(), ND->getLocEnd());
111    else if (TypeSourceInfo *TInfo = getFriendType())
112      return SourceRange(getFriendLoc(), TInfo->getTypeLoc().getEndLoc());
113    else
114      return SourceRange(getFriendLoc(), getLocation());
115  }
116
117  /// Determines if this friend kind is unsupported.
118  bool isUnsupportedFriend() const {
119    return UnsupportedFriend;
120  }
121  void setUnsupportedFriend(bool Unsupported) {
122    UnsupportedFriend = Unsupported;
123  }
124
125  // Implement isa/cast/dyncast/etc.
126  static bool classof(const Decl *D) { return classofKind(D->getKind()); }
127  static bool classof(const FriendDecl *D) { return true; }
128  static bool classofKind(Kind K) { return K == Decl::Friend; }
129
130  friend class ASTDeclReader;
131  friend class ASTDeclWriter;
132};
133
134/// An iterator over the friend declarations of a class.
135class CXXRecordDecl::friend_iterator {
136  FriendDecl *Ptr;
137
138  friend class CXXRecordDecl;
139  explicit friend_iterator(FriendDecl *Ptr) : Ptr(Ptr) {}
140public:
141  friend_iterator() {}
142
143  typedef FriendDecl *value_type;
144  typedef FriendDecl *reference;
145  typedef FriendDecl *pointer;
146  typedef int difference_type;
147  typedef std::forward_iterator_tag iterator_category;
148
149  reference operator*() const { return Ptr; }
150
151  friend_iterator &operator++() {
152    assert(Ptr && "attempt to increment past end of friend list");
153    Ptr = Ptr->getNextFriend();
154    return *this;
155  }
156
157  friend_iterator operator++(int) {
158    friend_iterator tmp = *this;
159    ++*this;
160    return tmp;
161  }
162
163  bool operator==(const friend_iterator &Other) const {
164    return Ptr == Other.Ptr;
165  }
166
167  bool operator!=(const friend_iterator &Other) const {
168    return Ptr != Other.Ptr;
169  }
170
171  friend_iterator &operator+=(difference_type N) {
172    assert(N >= 0 && "cannot rewind a CXXRecordDecl::friend_iterator");
173    while (N--)
174      ++*this;
175    return *this;
176  }
177
178  friend_iterator operator+(difference_type N) const {
179    friend_iterator tmp = *this;
180    tmp += N;
181    return tmp;
182  }
183};
184
185inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_begin() const {
186  return friend_iterator(data().FirstFriend);
187}
188
189inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_end() const {
190  return friend_iterator(0);
191}
192
193inline void CXXRecordDecl::pushFriendDecl(FriendDecl *FD) {
194  assert(FD->NextFriend == 0 && "friend already has next friend?");
195  FD->NextFriend = data().FirstFriend;
196  data().FirstFriend = FD;
197}
198
199}
200
201#endif
202