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1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2008 Google Inc.  All rights reserved.
3 // https://developers.google.com/protocol-buffers/
4 //
5 // Redistribution and use in source and binary forms, with or without
6 // modification, are permitted provided that the following conditions are
7 // met:
8 //
9 //     * Redistributions of source code must retain the above copyright
10 // notice, this list of conditions and the following disclaimer.
11 //     * Redistributions in binary form must reproduce the above
12 // copyright notice, this list of conditions and the following disclaimer
13 // in the documentation and/or other materials provided with the
14 // distribution.
15 //     * Neither the name of Google Inc. nor the names of its
16 // contributors may be used to endorse or promote products derived from
17 // this software without specific prior written permission.
18 //
19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 
31 // Author: kenton@google.com (Kenton Varda)
32 //  Based on original Protocol Buffers design by
33 //  Sanjay Ghemawat, Jeff Dean, and others.
34 
35 #ifndef GOOGLE_PROTOBUF_COMPILER_CPP_FIELD_H__
36 #define GOOGLE_PROTOBUF_COMPILER_CPP_FIELD_H__
37 
38 #include <map>
39 #include <memory>
40 #ifndef _SHARED_PTR_H
41 #include <google/protobuf/stubs/shared_ptr.h>
42 #endif
43 #include <string>
44 
45 #include <google/protobuf/descriptor.h>
46 #include <google/protobuf/compiler/cpp/cpp_options.h>
47 
48 namespace google {
49 namespace protobuf {
50   namespace io {
51     class Printer;             // printer.h
52   }
53 }
54 
55 namespace protobuf {
56 namespace compiler {
57 namespace cpp {
58 
59 // Helper function: set variables in the map that are the same for all
60 // field code generators.
61 // ['name', 'index', 'number', 'classname', 'declared_type', 'tag_size',
62 // 'deprecation'].
63 void SetCommonFieldVariables(const FieldDescriptor* descriptor,
64                              map<string, string>* variables,
65                              const Options& options);
66 
67 void SetCommonOneofFieldVariables(const FieldDescriptor* descriptor,
68                                   map<string, string>* variables);
69 
70 class FieldGenerator {
71  public:
FieldGenerator(const Options & options)72   explicit FieldGenerator(const Options& options) : options_(options) {}
73   virtual ~FieldGenerator();
74 
75   // Generate lines of code declaring members fields of the message class
76   // needed to represent this field.  These are placed inside the message
77   // class.
78   virtual void GeneratePrivateMembers(io::Printer* printer) const = 0;
79 
80   // Generate static default variable for this field. These are placed inside
81   // the message class. Most field types don't need this, so the default
82   // implementation is empty.
GenerateStaticMembers(io::Printer *)83   virtual void GenerateStaticMembers(io::Printer* /*printer*/) const {}
84 
85   // Generate prototypes for accessors that will manipulate imported
86   // messages inline.  These are for .proto.h headers.
87   //
88   // In .proto.h mode, the headers of imports are not #included. However,
89   // functions that manipulate the imported message types need access to
90   // the class definition of the imported message, meaning that the headers
91   // must be #included. To get around this, functions that manipulate
92   // imported message objects are defined as dependent functions in a base
93   // template class. By making them dependent template functions, the
94   // function templates will not be instantiated until they are called, so
95   // we can defer to those translation units to #include the necessary
96   // generated headers.
97   //
98   // See:
99   // http://en.cppreference.com/w/cpp/language/class_template#Implicit_instantiation
100   //
101   // Most field types don't need this, so the default implementation is empty.
GenerateDependentAccessorDeclarations(io::Printer * printer)102   virtual void GenerateDependentAccessorDeclarations(
103       io::Printer* printer) const {}
104 
105   // Generate prototypes for all of the accessor functions related to this
106   // field.  These are placed inside the class definition.
107   virtual void GenerateAccessorDeclarations(io::Printer* printer) const = 0;
108 
109   // Generate inline definitions of depenent accessor functions for this field.
110   // These are placed inside the header after all class definitions.
GenerateDependentInlineAccessorDefinitions(io::Printer * printer)111   virtual void GenerateDependentInlineAccessorDefinitions(
112     io::Printer* printer) const {}
113 
114   // Generate inline definitions of accessor functions for this field.
115   // These are placed inside the header after all class definitions.
116   // In non-.proto.h mode, this generates dependent accessor functions as well.
117   virtual void GenerateInlineAccessorDefinitions(
118     io::Printer* printer, bool is_inline) const = 0;
119 
120   // Generate definitions of accessors that aren't inlined.  These are
121   // placed somewhere in the .cc file.
122   // Most field types don't need this, so the default implementation is empty.
GenerateNonInlineAccessorDefinitions(io::Printer *)123   virtual void GenerateNonInlineAccessorDefinitions(
124     io::Printer* /*printer*/) const {}
125 
126   // Generate lines of code (statements, not declarations) which clear the
127   // field.  This is used to define the clear_$name$() method as well as
128   // the Clear() method for the whole message.
129   virtual void GenerateClearingCode(io::Printer* printer) const = 0;
130 
131   // Generate lines of code (statements, not declarations) which merges the
132   // contents of the field from the current message to the target message,
133   // which is stored in the generated code variable "from".
134   // This is used to fill in the MergeFrom method for the whole message.
135   // Details of this usage can be found in message.cc under the
136   // GenerateMergeFrom method.
137   virtual void GenerateMergingCode(io::Printer* printer) const = 0;
138 
139   // Generate lines of code (statements, not declarations) which swaps
140   // this field and the corresponding field of another message, which
141   // is stored in the generated code variable "other". This is used to
142   // define the Swap method. Details of usage can be found in
143   // message.cc under the GenerateSwap method.
144   virtual void GenerateSwappingCode(io::Printer* printer) const = 0;
145 
146   // Generate initialization code for private members declared by
147   // GeneratePrivateMembers(). These go into the message class's SharedCtor()
148   // method, invoked by each of the generated constructors.
149   virtual void GenerateConstructorCode(io::Printer* printer) const = 0;
150 
151   // Generate any code that needs to go in the class's SharedDtor() method,
152   // invoked by the destructor.
153   // Most field types don't need this, so the default implementation is empty.
GenerateDestructorCode(io::Printer *)154   virtual void GenerateDestructorCode(io::Printer* /*printer*/) const {}
155 
156   // Generate a manual destructor invocation for use when the message is on an
157   // arena. The code that this method generates will be executed inside a
158   // shared-for-the-whole-message-class method registered with OwnDestructor().
159   // The method should return |true| if it generated any code that requires a
160   // call; this allows the message generator to eliminate the OwnDestructor()
161   // registration if no fields require it.
GenerateArenaDestructorCode(io::Printer * printer)162   virtual bool GenerateArenaDestructorCode(io::Printer* printer) const {
163     return false;
164   }
165 
166   // Generate code that allocates the fields's default instance.
GenerateDefaultInstanceAllocator(io::Printer *)167   virtual void GenerateDefaultInstanceAllocator(io::Printer* /*printer*/)
168       const {}
169 
170   // Generate code that should be run when ShutdownProtobufLibrary() is called,
171   // to delete all dynamically-allocated objects.
GenerateShutdownCode(io::Printer *)172   virtual void GenerateShutdownCode(io::Printer* /*printer*/) const {}
173 
174   // Generate lines to decode this field, which will be placed inside the
175   // message's MergeFromCodedStream() method.
176   virtual void GenerateMergeFromCodedStream(io::Printer* printer) const = 0;
177 
178   // Generate lines to decode this field from a packed value, which will be
179   // placed inside the message's MergeFromCodedStream() method.
180   virtual void GenerateMergeFromCodedStreamWithPacking(io::Printer* printer)
181       const;
182 
183   // Generate lines to serialize this field, which are placed within the
184   // message's SerializeWithCachedSizes() method.
185   virtual void GenerateSerializeWithCachedSizes(io::Printer* printer) const = 0;
186 
187   // Generate lines to serialize this field directly to the array "target",
188   // which are placed within the message's SerializeWithCachedSizesToArray()
189   // method. This must also advance "target" past the written bytes.
190   virtual void GenerateSerializeWithCachedSizesToArray(
191       io::Printer* printer) const = 0;
192 
193   // Generate lines to compute the serialized size of this field, which
194   // are placed in the message's ByteSize() method.
195   virtual void GenerateByteSize(io::Printer* printer) const = 0;
196 
197  protected:
198   const Options& options_;
199 
200  private:
201   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(FieldGenerator);
202 };
203 
204 // Convenience class which constructs FieldGenerators for a Descriptor.
205 class FieldGeneratorMap {
206  public:
207   FieldGeneratorMap(const Descriptor* descriptor, const Options& options);
208   ~FieldGeneratorMap();
209 
210   const FieldGenerator& get(const FieldDescriptor* field) const;
211 
212  private:
213   const Descriptor* descriptor_;
214   const Options& options_;
215   google::protobuf::scoped_array<google::protobuf::scoped_ptr<FieldGenerator> > field_generators_;
216 
217   static FieldGenerator* MakeGenerator(const FieldDescriptor* field,
218                                        const Options& options);
219 
220   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(FieldGeneratorMap);
221 };
222 
223 
224 }  // namespace cpp
225 }  // namespace compiler
226 }  // namespace protobuf
227 
228 }  // namespace google
229 #endif  // GOOGLE_PROTOBUF_COMPILER_CPP_FIELD_H__
230