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1# Copyright 2020 The Pigweed Authors
2#
3# Licensed under the Apache License, Version 2.0 (the "License"); you may not
4# use this file except in compliance with the License. You may obtain a copy of
5# the License at
6#
7#     https://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
11# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12# License for the specific language governing permissions and limitations under
13# the License.
14"""pw_rpc protoc plugin entrypoint to generate code for RPC services."""
15
16import enum
17import sys
18
19import google.protobuf.compiler.plugin_pb2 as plugin_pb2
20
21import pw_rpc.codegen_nanopb as codegen_nanopb
22import pw_rpc.codegen_raw as codegen_raw
23
24
25class Codegen(enum.Enum):
26    RAW = 0
27    NANOPB = 1
28
29
30def process_proto_request(codegen: Codegen,
31                          req: plugin_pb2.CodeGeneratorRequest,
32                          res: plugin_pb2.CodeGeneratorResponse) -> None:
33    """Handles a protoc CodeGeneratorRequest message.
34
35    Generates code for the files in the request and writes the output to the
36    specified CodeGeneratorResponse message.
37
38    Args:
39      req: A CodeGeneratorRequest for a proto compilation.
40      res: A CodeGeneratorResponse to populate with the plugin's output.
41    """
42    for proto_file in req.proto_file:
43        if codegen is Codegen.RAW:
44            output_files = codegen_raw.process_proto_file(proto_file)
45        elif codegen is Codegen.NANOPB:
46            output_files = codegen_nanopb.process_proto_file(proto_file)
47        else:
48            raise NotImplementedError(f'Unknown codegen type {codegen}')
49
50        for output_file in output_files:
51            fd = res.file.add()
52            fd.name = output_file.name()
53            fd.content = output_file.content()
54
55
56def main(codegen: Codegen) -> int:
57    """Protobuf compiler plugin entrypoint.
58
59    Reads a CodeGeneratorRequest proto from stdin and writes a
60    CodeGeneratorResponse to stdout.
61    """
62    data = sys.stdin.buffer.read()
63    request = plugin_pb2.CodeGeneratorRequest.FromString(data)
64    response = plugin_pb2.CodeGeneratorResponse()
65    process_proto_request(codegen, request, response)
66
67    # Declare that this plugin supports optional fields in proto3. No proto
68    # message code is generated, so optional in proto3 is supported trivially.
69    response.supported_features |= (  # type: ignore[attr-defined]
70        response.FEATURE_PROTO3_OPTIONAL)  # type: ignore[attr-defined]
71
72    sys.stdout.buffer.write(response.SerializeToString())
73    return 0
74