pw_protobuf_compiler/ts/codegen/template_replacement.ts

#!/usr/bin/env node
// Copyright 2020 The Pigweed Authors
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.

import * as fs from 'fs';
import {ArgumentParser} from 'argparse';
import {FileDescriptorSet} from 'google-protobuf/google/protobuf/descriptor_pb';
// import {Message} from 'google-protobuf';

const parser = new ArgumentParser({});
parser.add_argument('--output', {
  action: 'store',
  required: true,
  type: String,
});
parser.add_argument('--descriptor_data', {
  action: 'store',
  required: true,
  type: String,
});
parser.add_argument('--template', {
  action: 'store',
  required: true,
  type: String,
});
parser.add_argument('--proto_root_dir', {
  action: 'store',
  required: true,
  type: String,
});

const args = parser.parse_args();
let template = fs.readFileSync(args.template).toString();

function buildModulePath(rootDir: string, fileName: string): string {
  const name = `${rootDir}/${fileName}`;
  return name.replace(/\.proto$/, '_pb');
}

const descriptorSetBinary = fs.readFileSync(args.descriptor_data);
const base64DescriptorSet = descriptorSetBinary.toString('base64');
const fileDescriptorSet = FileDescriptorSet.deserializeBinary(
  new Buffer(descriptorSetBinary)
);

const imports = [];
const moduleDictionary = [];
const fileList = fileDescriptorSet.getFileList();
for (let i = 0; i < fileList.length; i++) {
  const file = fileList[i];
  const modulePath = buildModulePath(args.proto_root_dir, file.getName()!);
  const moduleName = 'proto_' + i;
  imports.push(`import * as ${moduleName} from '${modulePath}';`);
  const key = file.getName()!;
  moduleDictionary.push(`['${key}', ${moduleName}],`);
}

template = template.replace(
  '{TEMPLATE_descriptor_binary}',
  base64DescriptorSet
);
template = template.replace('// TEMPLATE_proto_imports', imports.join('\n'));
template = template.replace(
  '// TEMPLATE_module_map',
  moduleDictionary.join('\n')
);

fs.writeFileSync(args.output, template);