1 //===--- RefactoringOptionVisitor.h - Clang refactoring library -----------===//
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_TOOLING_REFACTORING_REFACTORINGOPTIONVISITOR_H
10 #define LLVM_CLANG_TOOLING_REFACTORING_REFACTORINGOPTIONVISITOR_H
11 
12 #include "clang/Basic/LLVM.h"
13 #include <optional>
14 #include <type_traits>
15 
16 namespace clang {
17 namespace tooling {
18 
19 class RefactoringOption;
20 
21 /// An interface that declares functions that handle different refactoring
22 /// option types.
23 ///
24 /// A valid refactoring option type must have a corresponding \c visit
25 /// declaration in this interface.
26 class RefactoringOptionVisitor {
27 public:
28   virtual ~RefactoringOptionVisitor() {}
29 
30   virtual void visit(const RefactoringOption &Opt,
31                      std::optional<std::string> &Value) = 0;
32 };
33 
34 namespace traits {
35 namespace internal {
36 
37 template <typename T> struct HasHandle {
38 private:
39   template <typename ClassT>
40   static auto check(ClassT *) -> typename std::is_same<
41       decltype(std::declval<RefactoringOptionVisitor>().visit(
42           std::declval<RefactoringOption>(),
43           *std::declval<std::optional<T> *>())),
44       void>::type;
45 
46   template <typename> static std::false_type check(...);
47 
48 public:
49   using Type = decltype(check<RefactoringOptionVisitor>(nullptr));
50 };
51 
52 } // end namespace internal
53 
54 /// A type trait that returns true iff the given type is a type that can be
55 /// stored in a refactoring option.
56 template <typename T>
57 struct IsValidOptionType : internal::HasHandle<T>::Type {};
58 
59 } // end namespace traits
60 } // end namespace tooling
61 } // end namespace clang
62 
63 #endif // LLVM_CLANG_TOOLING_REFACTORING_REFACTORINGOPTIONVISITOR_H
64