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
16namespace clang {
17namespace comments {
18template <template <typename> class Ptr, typename ImplClass,
19          typename RetTy = void, class... ParamTys>
20class CommentVisitorBase {
21public:
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
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 CommentKind::CLASS:                                                     \
36    DISPATCH(CLASS, CLASS);
37#include "clang/AST/CommentNodes.inc"
38#undef ABSTRACT_COMMENT
39#undef COMMENT
40    }
41  }
42
43  // If the derived class does not implement a certain Visit* method, fall back
44  // on Visit* method for the superclass.
45#define ABSTRACT_COMMENT(COMMENT) COMMENT
46#define COMMENT(CLASS, PARENT)                                                 \
47  RetTy visit##CLASS(PTR(CLASS) C, ParamTys... P) { DISPATCH(PARENT, PARENT); }
48#include "clang/AST/CommentNodes.inc"
49#undef ABSTRACT_COMMENT
50#undef COMMENT
51
52  RetTy visitComment(PTR(Comment) C, ParamTys... P) { return RetTy(); }
53
54#undef PTR
55#undef DISPATCH
56};
57
58template <typename ImplClass, typename RetTy = void, class... ParamTys>
59class CommentVisitor : public CommentVisitorBase<std::add_pointer, ImplClass,
60                                                 RetTy, ParamTys...> {};
61
62template <typename ImplClass, typename RetTy = void, class... ParamTys>
63class ConstCommentVisitor
64    : public CommentVisitorBase<llvm::make_const_ptr, ImplClass, RetTy,
65                                ParamTys...> {};
66
67} // namespace comments
68} // namespace clang
69
70#endif // LLVM_CLANG_AST_COMMENTVISITOR_H
71