cpp_field.h

Go to the documentation of this file.

// 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: [email protected] (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>
#include <string>

#include <google/protobuf/descriptor.h>
#include "google/protobuf/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,
 map<string, string>* variables,
 const Options& options);

void SetCommonOneofFieldVariables(const FieldDescriptor* descriptor,
 map<string, string>* variables);

class FieldGenerator {
 public:
 FieldGenerator() {}
 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 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 accessor functions for this field.
 // These are placed inside the header after all class definitions.
 virtual void GenerateInlineAccessorDefinitions(
 io::Printer* printer) 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 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;

 private:
 GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(FieldGenerator);
};

// Convenience class which constructs FieldGenerators for a Descriptor.
class FieldGeneratorMap {
 public:
 explicit FieldGeneratorMap(const Descriptor* descriptor, const Options& options);
 ~FieldGeneratorMap();

 const FieldGenerator& get(const FieldDescriptor* field) const;

 private:
 const Descriptor* descriptor_;
 scoped_array<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__