src/main/java/com/google/devtools/build/skydoc/renderer/RendererMain.java

// Copyright 2019 The Bazel Authors. All rights reserved.
//
// 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
//
//    http://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.
package com.google.devtools.build.skydoc.renderer;

import com.google.devtools.common.options.OptionsParser;
import java.io.IOException;

/**
 * Main entry point for Renderer binary.
 *
 * <p>This Renderer will take in raw stardoc_proto protos as input and produce rich markdown output.
 */
public class RendererMain {
  public static void main(String[] args) throws IOException {
    OptionsParser parser = OptionsParser.builder().optionsClasses(RendererOptions.class).build();
    parser.parseAndExitUponError(args);
    RendererOptions rendererOptions = parser.getOptions(RendererOptions.class);

    if (rendererOptions.inputPath.isEmpty() || rendererOptions.outputFilePath.isEmpty()) {
      throw new IllegalArgumentException(
          "Both --input and --output must be specified. Usage: "
              + "{renderer_bin} --input=\"{input_proto_file}\" --output=\"{output_file}\"");
    }

    RendererMain rendererMain = new RendererMain();
    String inputPath = rendererOptions.inputPath;
    String outputPath = rendererOptions.outputFilePath;
    rendererMain.copyProtoFile(inputPath, outputPath);
  }

  // TODO(kendalllane, blossomsm): Implement proto to markdown conversion.
  /** Copies the input proto file to the output location */
  public void copyProtoFile(String inputPath, String outputPath) throws IOException {
    ProtoFileAccessor fileAccessor = new FileSystemAccessor();
    if (fileAccessor.fileExists(inputPath)) {
      byte[] inputContent = fileAccessor.getProtoContent(inputPath);
      fileAccessor.writeToOutputLocation(outputPath, inputContent);
    } else {
      throw new IOException(inputPath + " does not exist.");
    }
  }
}