text: // Protocol Buffers - Google's data interchange format
  // Copyright 2008 Google Inc.  All rights reserved.
  // https://developers.google.com/protocol-buffers/
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  //     * Neither the name of Google Inc. nor the names of its
  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  // Author: kenton@google.com (Kenton Varda)
  //  Based on original Protocol Buffers design by
  //  Sanjay Ghemawat, Jeff Dean, and others.
  
  #ifndef GOOGLE_PROTOBUF_COMPILER_CPP_FIELD_H__
  #define GOOGLE_PROTOBUF_COMPILER_CPP_FIELD_H__
  
  #include <map>
  #include <memory>
  #ifndef _SHARED_PTR_H
  #include "stubs/shared_ptr.h"
  #endif
  
  #include "descriptor.h"
  #include "compiler/cpp/cpp_options.h"
  
  namespace google {
  namespace protobuf {
    namespace io {
      class Printer;             // printer.h
    }
  }
  
  namespace protobuf {
  namespace compiler {
  namespace cpp {
  
  // Helper function: set variables in the map that are the same for all
  // field code generators.
  // ['name', 'index', 'number', 'classname', 'declared_type', 'tag_size',
  // 'deprecation'].
  void SetCommonFieldVariables(const FieldDescriptor* descriptor,
                               std::map<string, string>* variables,
                               const Options& options);
  
  void SetCommonOneofFieldVariables(const FieldDescriptor* descriptor,
                                    std::map<string, string>* variables);
  
  class FieldGenerator {
   public:
    explicit FieldGenerator(const Options& options) : options_(options) {}
    virtual ~FieldGenerator();
  
    // Generate lines of code declaring members fields of the message class
    // needed to represent this field.  These are placed inside the message
    // class.
    virtual void GeneratePrivateMembers(io::Printer* printer) const = 0;
  
    // Generate static default variable for this field. These are placed inside
    // the message class. Most field types don't need this, so the default
    // implementation is empty.
    virtual void GenerateStaticMembers(io::Printer* /*printer*/) const {}
  
    // Generate prototypes for accessors that will manipulate imported
    // messages inline.  These are for .proto.h headers.
    //
    // In .proto.h mode, the headers of imports are not #included. However,
    // functions that manipulate the imported message types need access to
    // the class definition of the imported message, meaning that the headers
    // must be #included. To get around this, functions that manipulate
    // imported message objects are defined as dependent functions in a base
    // template class. By making them dependent template functions, the
    // function templates will not be instantiated until they are called, so
    // we can defer to those translation units to #include the necessary
    // generated headers.
    //
    // See:
    // http://en.cppreference.com/w/cpp/language/class_template#Implicit_instantiation
    //
    // Most field types don't need this, so the default implementation is empty.
    virtual void GenerateDependentAccessorDeclarations(
        io::Printer* printer) const {}
  
    // Generate prototypes for all of the accessor functions related to this
    // field.  These are placed inside the class definition.
    virtual void GenerateAccessorDeclarations(io::Printer* printer) const = 0;
  
    // Generate inline definitions of depenent accessor functions for this field.
    // These are placed inside the header after all class definitions.
    virtual void GenerateDependentInlineAccessorDefinitions(
      io::Printer* printer) const {}
  
    // Generate inline definitions of accessor functions for this field.
    // These are placed inside the header after all class definitions.
    // In non-.proto.h mode, this generates dependent accessor functions as well.
    virtual void GenerateInlineAccessorDefinitions(
      io::Printer* printer, bool is_inline) const = 0;
  
    // Generate definitions of accessors that aren't inlined.  These are
    // placed somewhere in the .cc file.
    // Most field types don't need this, so the default implementation is empty.
    virtual void GenerateNonInlineAccessorDefinitions(
      io::Printer* /*printer*/) const {}
  
    // Generate lines of code (statements, not declarations) which clear the
    // field.  This is used to define the clear_$name$() method as well as
    // the Clear() method for the whole message.
    virtual void GenerateClearingCode(io::Printer* printer) const = 0;
  
    // Generate lines of code (statements, not declarations) which merges the
    // contents of the field from the current message to the target message,
    // which is stored in the generated code variable "from".
    // This is used to fill in the MergeFrom method for the whole message.
    // Details of this usage can be found in message.cc under the
    // GenerateMergeFrom method.
    virtual void GenerateMergingCode(io::Printer* printer) const = 0;
  
    // Generate lines of code (statements, not declarations) which swaps
    // this field and the corresponding field of another message, which
    // is stored in the generated code variable "other". This is used to
    // define the Swap method. Details of usage can be found in
    // message.cc under the GenerateSwap method.
    virtual void GenerateSwappingCode(io::Printer* printer) const = 0;
  
    // Generate initialization code for private members declared by
    // GeneratePrivateMembers(). These go into the message class's SharedCtor()
    // method, invoked by each of the generated constructors.
    virtual void GenerateConstructorCode(io::Printer* printer) const = 0;
  
    // Generate any code that needs to go in the class's SharedDtor() method,
    // invoked by the destructor.
    // Most field types don't need this, so the default implementation is empty.
    virtual void GenerateDestructorCode(io::Printer* /*printer*/) const {}
  
    // Generate a manual destructor invocation for use when the message is on an
    // arena. The code that this method generates will be executed inside a
    // shared-for-the-whole-message-class method registered with OwnDestructor().
    // The method should return |true| if it generated any code that requires a
    // call; this allows the message generator to eliminate the OwnDestructor()
    // registration if no fields require it.
    virtual bool GenerateArenaDestructorCode(io::Printer* printer) const {
      return false;
    }
  
    // Generate code that allocates the fields's default instance.
    virtual void GenerateDefaultInstanceAllocator(io::Printer* /*printer*/)
        const {}
  
    // Generate code that should be run when ShutdownProtobufLibrary() is called,
    // to delete all dynamically-allocated objects.
    virtual void GenerateShutdownCode(io::Printer* /*printer*/) const {}
  
    // Generate lines to decode this field, which will be placed inside the
    // message's MergeFromCodedStream() method.
    virtual void GenerateMergeFromCodedStream(io::Printer* printer) const = 0;
  
    // Generate lines to decode this field from a packed value, which will be
    // placed inside the message's MergeFromCodedStream() method.
    virtual void GenerateMergeFromCodedStreamWithPacking(io::Printer* printer)
        const;
  
    // Generate lines to serialize this field, which are placed within the
    // message's SerializeWithCachedSizes() method.
    virtual void GenerateSerializeWithCachedSizes(io::Printer* printer) const = 0;
  
    // Generate lines to serialize this field directly to the array "target",
    // which are placed within the message's SerializeWithCachedSizesToArray()
    // method. This must also advance "target" past the written bytes.
    virtual void GenerateSerializeWithCachedSizesToArray(
        io::Printer* printer) const = 0;
  
    // Generate lines to compute the serialized size of this field, which
    // are placed in the message's ByteSize() method.
    virtual void GenerateByteSize(io::Printer* printer) const = 0;
  
   protected:
    const Options& options_;
  
   private:
    GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(FieldGenerator);
  };
  
  // Convenience class which constructs FieldGenerators for a Descriptor.
  class FieldGeneratorMap {
   public:
    FieldGeneratorMap(const Descriptor* descriptor, const Options& options);
    ~FieldGeneratorMap();
  
    const FieldGenerator& get(const FieldDescriptor* field) const;
  
   private:
    const Descriptor* descriptor_;
    const Options& options_;
    google::protobuf::scoped_array<google::protobuf::scoped_ptr<FieldGenerator> > field_generators_;
  
    static FieldGenerator* MakeGenerator(const FieldDescriptor* field,
                                         const Options& options);
  
    GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(FieldGeneratorMap);
  };
  
  
  }  // namespace cpp
  }  // namespace compiler
  }  // namespace protobuf
  
  }  // namespace google
  #endif  // GOOGLE_PROTOBUF_COMPILER_CPP_FIELD_H__
  