1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2023 Google Inc. All rights reserved.
3 //
4 // Use of this source code is governed by a BSD-style
5 // license that can be found in the LICENSE file or at
6 // https://developers.google.com/open-source/licenses/bsd
7
8 #ifndef GOOGLE_PROTOBUF_DESCRIPTOR_VISITOR_H__
9 #define GOOGLE_PROTOBUF_DESCRIPTOR_VISITOR_H__
10
11 #include "google/protobuf/descriptor.h"
12 #include "google/protobuf/descriptor.pb.h"
13 #include "google/protobuf/generated_message_reflection.h"
14
15 namespace google {
16 namespace protobuf {
17 namespace internal {
18
19 // Visit every node in the descriptors calling `visitor(node, proto)`.
20 // The visitor does not need to handle all possible node types. Types that are
21 // not visitable via `visitor` will be ignored.
22 template <typename Visitor>
23 void VisitDescriptors(const FileDescriptor& file,
24 const FileDescriptorProto& proto, Visitor visitor);
25
26 template <typename Visitor>
27 void VisitDescriptors(const FileDescriptor& file, FileDescriptorProto& proto,
28 Visitor visitor);
29
30 // Visit just the descriptors, without a corresponding proto tree.
31 template <typename Visitor>
32 void VisitDescriptors(const FileDescriptor& file, Visitor visitor);
33
34 template <typename Visitor>
35 struct VisitImpl {
36 Visitor visitor;
37 template <typename... Proto>
VisitVisitImpl38 void Visit(const FieldDescriptor& descriptor, Proto&... proto) {
39 visitor(descriptor, proto...);
40 }
41
42 template <typename... Proto>
VisitVisitImpl43 void Visit(const EnumValueDescriptor& descriptor, Proto&... proto) {
44 visitor(descriptor, proto...);
45 }
46
47 template <typename... Proto>
VisitVisitImpl48 void Visit(const EnumDescriptor& descriptor, Proto&... proto) {
49 visitor(descriptor, proto...);
50 for (int i = 0; i < descriptor.value_count(); i++) {
51 Visit(*descriptor.value(i), value(proto, i)...);
52 }
53 }
54
55 template <typename... Proto>
VisitVisitImpl56 void Visit(const Descriptor::ExtensionRange& descriptor, Proto&... proto) {
57 visitor(descriptor, proto...);
58 }
59
60 template <typename... Proto>
VisitVisitImpl61 void Visit(const OneofDescriptor& descriptor, Proto&... proto) {
62 visitor(descriptor, proto...);
63 }
64
65 template <typename... Proto>
VisitVisitImpl66 void Visit(const Descriptor& descriptor, Proto&... proto) {
67 visitor(descriptor, proto...);
68
69 for (int i = 0; i < descriptor.enum_type_count(); i++) {
70 Visit(*descriptor.enum_type(i), enum_type(proto, i)...);
71 }
72
73 for (int i = 0; i < descriptor.oneof_decl_count(); i++) {
74 Visit(*descriptor.oneof_decl(i), oneof_decl(proto, i)...);
75 }
76
77 for (int i = 0; i < descriptor.field_count(); i++) {
78 Visit(*descriptor.field(i), field(proto, i)...);
79 }
80
81 for (int i = 0; i < descriptor.nested_type_count(); i++) {
82 Visit(*descriptor.nested_type(i), nested_type(proto, i)...);
83 }
84
85 for (int i = 0; i < descriptor.extension_count(); i++) {
86 Visit(*descriptor.extension(i), extension(proto, i)...);
87 }
88
89 for (int i = 0; i < descriptor.extension_range_count(); i++) {
90 Visit(*descriptor.extension_range(i), extension_range(proto, i)...);
91 }
92 }
93
94 template <typename... Proto>
VisitVisitImpl95 void Visit(const MethodDescriptor& method, Proto&... proto) {
96 visitor(method, proto...);
97 }
98
99 template <typename... Proto>
VisitVisitImpl100 void Visit(const ServiceDescriptor& descriptor, Proto&... proto) {
101 visitor(descriptor, proto...);
102 for (int i = 0; i < descriptor.method_count(); i++) {
103 Visit(*descriptor.method(i), method(proto, i)...);
104 }
105 }
106
107 template <typename... Proto>
VisitVisitImpl108 void Visit(const FileDescriptor& descriptor, Proto&... proto) {
109 visitor(descriptor, proto...);
110 for (int i = 0; i < descriptor.message_type_count(); i++) {
111 Visit(*descriptor.message_type(i), message_type(proto, i)...);
112 }
113 for (int i = 0; i < descriptor.enum_type_count(); i++) {
114 Visit(*descriptor.enum_type(i), enum_type(proto, i)...);
115 }
116 for (int i = 0; i < descriptor.extension_count(); i++) {
117 Visit(*descriptor.extension(i), extension(proto, i)...);
118 }
119 for (int i = 0; i < descriptor.service_count(); i++) {
120 Visit(*descriptor.service(i), service(proto, i)...);
121 }
122 }
123
124 private:
125 #define CREATE_NESTED_GETTER(TYPE, NESTED) \
126 inline auto& NESTED(TYPE& desc, int i) { return *desc.mutable_##NESTED(i); } \
127 inline auto& NESTED(const TYPE& desc, int i) { return desc.NESTED(i); }
128
129 CREATE_NESTED_GETTER(DescriptorProto, enum_type);
130 CREATE_NESTED_GETTER(DescriptorProto, extension);
131 CREATE_NESTED_GETTER(DescriptorProto, extension_range);
132 CREATE_NESTED_GETTER(DescriptorProto, field);
133 CREATE_NESTED_GETTER(DescriptorProto, nested_type);
134 CREATE_NESTED_GETTER(DescriptorProto, oneof_decl);
135 CREATE_NESTED_GETTER(EnumDescriptorProto, value);
136 CREATE_NESTED_GETTER(FileDescriptorProto, enum_type);
137 CREATE_NESTED_GETTER(FileDescriptorProto, extension);
138 CREATE_NESTED_GETTER(FileDescriptorProto, message_type);
139 CREATE_NESTED_GETTER(FileDescriptorProto, service);
140 CREATE_NESTED_GETTER(ServiceDescriptorProto, method);
141
142 #undef CREATE_NESTED_GETTER
143 };
144
145 // Provide a fallback to ignore all the nodes that are not interesting to the
146 // input visitor.
147 template <typename Visitor>
148 struct VisitorImpl : Visitor {
VisitorImplVisitorImpl149 explicit VisitorImpl(Visitor visitor) : Visitor(visitor) {}
150
151 // Pull in all of the supplied callbacks.
152 using Visitor::operator();
153
154 // Honeypots to ignore all inputs that Visitor does not take.
155 struct DescriptorEater {
156 template <typename T>
DescriptorEaterVisitorImpl::DescriptorEater157 DescriptorEater(T&&) {} // NOLINT
158 };
operatorVisitorImpl159 void operator()(DescriptorEater, DescriptorEater) const {}
operatorVisitorImpl160 void operator()(DescriptorEater) const {}
161 };
162
163 template <typename Visitor>
VisitDescriptors(const FileDescriptor & file,const FileDescriptorProto & proto,Visitor visitor)164 void VisitDescriptors(const FileDescriptor& file,
165 const FileDescriptorProto& proto, Visitor visitor) {
166 using VisitorImpl = internal::VisitorImpl<Visitor>;
167 internal::VisitImpl<VisitorImpl>{VisitorImpl(visitor)}.Visit(file, proto);
168 }
169
170 template <typename Visitor>
VisitDescriptors(const FileDescriptor & file,FileDescriptorProto & proto,Visitor visitor)171 void VisitDescriptors(const FileDescriptor& file, FileDescriptorProto& proto,
172 Visitor visitor) {
173 using VisitorImpl = internal::VisitorImpl<Visitor>;
174 internal::VisitImpl<VisitorImpl>{VisitorImpl(visitor)}.Visit(file, proto);
175 }
176
177 template <typename Visitor>
VisitDescriptors(const FileDescriptor & file,Visitor visitor)178 void VisitDescriptors(const FileDescriptor& file, Visitor visitor) {
179 using VisitorImpl = internal::VisitorImpl<Visitor>;
180 internal::VisitImpl<VisitorImpl>{VisitorImpl(visitor)}.Visit(file);
181 }
182
183 } // namespace internal
184 } // namespace protobuf
185 } // namespace google
186
187 #endif // GOOGLE_PROTOBUF_DESCRIPTOR_VISITOR_H__
188