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,
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25// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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29// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30
31// Author: kenton@google.com (Kenton Varda)
32//
33// Front-end for protoc code generator plugins written in C++.
34//
35// To implement a protoc plugin in C++, simply write an implementation of
36// CodeGenerator, then create a main() function like:
37//   int main(int argc, char* argv[]) {
38//     MyCodeGenerator generator;
39//     return google::protobuf::compiler::PluginMain(argc, argv, &generator);
40//   }
41// You must link your plugin against libprotobuf and libprotoc.
42//
43// The core part of PluginMain is to invoke the given CodeGenerator on a
44// CodeGeneratorRequest to generate a CodeGeneratorResponse. This part is
45// abstracted out and made into function GenerateCode so that it can be reused,
46// for example, to implement a variant of PluginMain that does some
47// preprocessing on the input CodeGeneratorRequest before feeding the request
48// to the given code generator.
49//
50// To get protoc to use the plugin, do one of the following:
51// * Place the plugin binary somewhere in the PATH and give it the name
52//   "protoc-gen-NAME" (replacing "NAME" with the name of your plugin).  If you
53//   then invoke protoc with the parameter --NAME_out=OUT_DIR (again, replace
54//   "NAME" with your plugin's name), protoc will invoke your plugin to generate
55//   the output, which will be placed in OUT_DIR.
56// * Place the plugin binary anywhere, with any name, and pass the --plugin
57//   parameter to protoc to direct it to your plugin like so:
58//     protoc --plugin=protoc-gen-NAME=path/to/mybinary --NAME_out=OUT_DIR
59//   On Windows, make sure to include the .exe suffix:
60//     protoc --plugin=protoc-gen-NAME=path/to/mybinary.exe --NAME_out=OUT_DIR
61
62#ifndef GOOGLE_PROTOBUF_COMPILER_PLUGIN_H__
63#define GOOGLE_PROTOBUF_COMPILER_PLUGIN_H__
64
65#include <string>
66
67#include <google/protobuf/stubs/common.h>
68namespace google {
69namespace protobuf {
70namespace compiler {
71
72class CodeGenerator;    // code_generator.h
73class CodeGeneratorRequest;
74class CodeGeneratorResponse;
75
76// Implements main() for a protoc plugin exposing the given code generator.
77LIBPROTOC_EXPORT int PluginMain(int argc, char* argv[], const CodeGenerator* generator);
78
79// Generates code using the given code generator. Returns true if the code
80// generation is successful. If the code geneartion fails, error_msg may be
81// populated to describe the failure cause.
82bool GenerateCode(const CodeGeneratorRequest& request,
83    const CodeGenerator& generator, CodeGeneratorResponse* response,
84    string* error_msg);
85
86}  // namespace compiler
87}  // namespace protobuf
88
89}  // namespace google
90#endif  // GOOGLE_PROTOBUF_COMPILER_PLUGIN_H__
91