1 //===- CommentVisitor.h - Visitor for Comment subclasses --------*- 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 #ifndef LLVM_CLANG_AST_COMMENTVISITOR_H
10 #define LLVM_CLANG_AST_COMMENTVISITOR_H
11 
12 #include "clang/AST/Comment.h"
13 #include "llvm/ADT/STLExtras.h"
14 #include "llvm/Support/ErrorHandling.h"
15 
16 namespace clang {
17 namespace comments {
18 template <template <typename> class Ptr, typename ImplClass,
19           typename RetTy = void, class... ParamTys>
20 class CommentVisitorBase {
21 public:
22 #define PTR(CLASS) typename Ptr<CLASS>::type
23 #define DISPATCH(NAME, CLASS)                                                  \
24   return static_cast<ImplClass *>(this)->visit##NAME(                          \
25       static_cast<PTR(CLASS)>(C), std::forward<ParamTys>(P)...)
26 
visit(PTR (Comment)C,ParamTys...P)27   RetTy visit(PTR(Comment) C, ParamTys... P) {
28     if (!C)
29       return RetTy();
30 
31     switch (C->getCommentKind()) {
32     default: llvm_unreachable("Unknown comment kind!");
33 #define ABSTRACT_COMMENT(COMMENT)
34 #define COMMENT(CLASS, PARENT) \
35     case Comment::CLASS##Kind: DISPATCH(CLASS, CLASS);
36 #include "clang/AST/CommentNodes.inc"
37 #undef ABSTRACT_COMMENT
38 #undef COMMENT
39     }
40   }
41 
42   // If the derived class does not implement a certain Visit* method, fall back
43   // on Visit* method for the superclass.
44 #define ABSTRACT_COMMENT(COMMENT) COMMENT
45 #define COMMENT(CLASS, PARENT)                                                 \
46   RetTy visit##CLASS(PTR(CLASS) C, ParamTys... P) { DISPATCH(PARENT, PARENT); }
47 #include "clang/AST/CommentNodes.inc"
48 #undef ABSTRACT_COMMENT
49 #undef COMMENT
50 
visitComment(PTR (Comment)C,ParamTys...P)51   RetTy visitComment(PTR(Comment) C, ParamTys... P) { return RetTy(); }
52 
53 #undef PTR
54 #undef DISPATCH
55 };
56 
57 template <typename ImplClass, typename RetTy = void, class... ParamTys>
58 class CommentVisitor : public CommentVisitorBase<std::add_pointer, ImplClass,
59                                                  RetTy, ParamTys...> {};
60 
61 template <typename ImplClass, typename RetTy = void, class... ParamTys>
62 class ConstCommentVisitor
63     : public CommentVisitorBase<llvm::make_const_ptr, ImplClass, RetTy,
64                                 ParamTys...> {};
65 
66 } // namespace comments
67 } // namespace clang
68 
69 #endif // LLVM_CLANG_AST_COMMENTVISITOR_H
70