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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 (a] google.com (Kenton Varda)
     32 //
     33 // WARNING:  The plugin interface is currently EXPERIMENTAL and is subject to
     34 //   change.
     35 //
     36 // protoc (aka the Protocol Compiler) can be extended via plugins.  A plugin is
     37 // just a program that reads a CodeGeneratorRequest from stdin and writes a
     38 // CodeGeneratorResponse to stdout.
     39 //
     40 // Plugins written using C++ can use google/protobuf/compiler/plugin.h instead
     41 // of dealing with the raw protocol defined here.
     42 //
     43 // A plugin executable needs only to be placed somewhere in the path.  The
     44 // plugin should be named "protoc-gen-$NAME", and will then be used when the
     45 // flag "--${NAME}_out" is passed to protoc.
     46 
     47 syntax = "proto2";
     48 package google.protobuf.compiler;
     49 option java_package = "com.google.protobuf.compiler";
     50 option java_outer_classname = "PluginProtos";
     51 
     52 option go_package = "plugin_go";
     53 
     54 import "google/protobuf/descriptor.proto";
     55 
     56 // An encoded CodeGeneratorRequest is written to the plugin's stdin.
     57 message CodeGeneratorRequest {
     58   // The .proto files that were explicitly listed on the command-line.  The
     59   // code generator should generate code only for these files.  Each file's
     60   // descriptor will be included in proto_file, below.
     61   repeated string file_to_generate = 1;
     62 
     63   // The generator parameter passed on the command-line.
     64   optional string parameter = 2;
     65 
     66   // FileDescriptorProtos for all files in files_to_generate and everything
     67   // they import.  The files will appear in topological order, so each file
     68   // appears before any file that imports it.
     69   //
     70   // protoc guarantees that all proto_files will be written after
     71   // the fields above, even though this is not technically guaranteed by the
     72   // protobuf wire format.  This theoretically could allow a plugin to stream
     73   // in the FileDescriptorProtos and handle them one by one rather than read
     74   // the entire set into memory at once.  However, as of this writing, this
     75   // is not similarly optimized on protoc's end -- it will store all fields in
     76   // memory at once before sending them to the plugin.
     77   repeated FileDescriptorProto proto_file = 15;
     78 }
     79 
     80 // The plugin writes an encoded CodeGeneratorResponse to stdout.
     81 message CodeGeneratorResponse {
     82   // Error message.  If non-empty, code generation failed.  The plugin process
     83   // should exit with status code zero even if it reports an error in this way.
     84   //
     85   // This should be used to indicate errors in .proto files which prevent the
     86   // code generator from generating correct code.  Errors which indicate a
     87   // problem in protoc itself -- such as the input CodeGeneratorRequest being
     88   // unparseable -- should be reported by writing a message to stderr and
     89   // exiting with a non-zero status code.
     90   optional string error = 1;
     91 
     92   // Represents a single generated file.
     93   message File {
     94     // The file name, relative to the output directory.  The name must not
     95     // contain "." or ".." components and must be relative, not be absolute (so,
     96     // the file cannot lie outside the output directory).  "/" must be used as
     97     // the path separator, not "\".
     98     //
     99     // If the name is omitted, the content will be appended to the previous
    100     // file.  This allows the generator to break large files into small chunks,
    101     // and allows the generated text to be streamed back to protoc so that large
    102     // files need not reside completely in memory at one time.  Note that as of
    103     // this writing protoc does not optimize for this -- it will read the entire
    104     // CodeGeneratorResponse before writing files to disk.
    105     optional string name = 1;
    106 
    107     // If non-empty, indicates that the named file should already exist, and the
    108     // content here is to be inserted into that file at a defined insertion
    109     // point.  This feature allows a code generator to extend the output
    110     // produced by another code generator.  The original generator may provide
    111     // insertion points by placing special annotations in the file that look
    112     // like:
    113     //   @@protoc_insertion_point(NAME)
    114     // The annotation can have arbitrary text before and after it on the line,
    115     // which allows it to be placed in a comment.  NAME should be replaced with
    116     // an identifier naming the point -- this is what other generators will use
    117     // as the insertion_point.  Code inserted at this point will be placed
    118     // immediately above the line containing the insertion point (thus multiple
    119     // insertions to the same point will come out in the order they were added).
    120     // The double-@ is intended to make it unlikely that the generated code
    121     // could contain things that look like insertion points by accident.
    122     //
    123     // For example, the C++ code generator places the following line in the
    124     // .pb.h files that it generates:
    125     //   // @@protoc_insertion_point(namespace_scope)
    126     // This line appears within the scope of the file's package namespace, but
    127     // outside of any particular class.  Another plugin can then specify the
    128     // insertion_point "namespace_scope" to generate additional classes or
    129     // other declarations that should be placed in this scope.
    130     //
    131     // Note that if the line containing the insertion point begins with
    132     // whitespace, the same whitespace will be added to every line of the
    133     // inserted text.  This is useful for languages like Python, where
    134     // indentation matters.  In these languages, the insertion point comment
    135     // should be indented the same amount as any inserted code will need to be
    136     // in order to work correctly in that context.
    137     //
    138     // The code generator that generates the initial file and the one which
    139     // inserts into it must both run as part of a single invocation of protoc.
    140     // Code generators are executed in the order in which they appear on the
    141     // command line.
    142     //
    143     // If |insertion_point| is present, |name| must also be present.
    144     optional string insertion_point = 2;
    145 
    146     // The file contents.
    147     optional string content = 15;
    148   }
    149   repeated File file = 15;
    150 }
    151