function readArgsAndExecCommand()

in packages/buck-worker-tool/src/worker-tool.js [191:242]

• 43 lines of code
• 4 McCabe index (conditional complexity)

function readArgsAndExecCommand(
  message: CommandMessage,
  commands: Commands,
  stdout: Writable,
  stderr: Writable,
  respond: RespondFn,
) {
  const {id} = message;

  fs.readFile(message.args_path, 'utf8', (readError, argsString) => {
    if (readError) {
      respond(invalidMessage(id));
      return;
    }

    let commandName;
    let args = [];
    let structuredArgs = null;

    // If it starts with a left brace, we assume it's JSON-encoded. This works
    // because the non-JSON encoding always starts the string with the
    // command name, thus a letter.
    if (argsString[0] === '{') {
      ({command: commandName, ...structuredArgs} = JSON.parse(argsString));
    } else {
      // FIXME: if there are files names with escaped
      // whitespace, this will not work.
      [commandName, ...args] = argsString.split(/\s+/);
    }

    if (commands.hasOwnProperty(commandName)) {
      const command = commands[commandName];
      const commandSpecificConsole = new Console(stdout, stderr);
      execCommand(
        command,
        commandName,
        argsString,
        args,
        structuredArgs,
        commandSpecificConsole,
        respond,
        id,
      );
    } else {
      stderr.write(
        `This worker does not have a command named \`${commandName}\`. ` +
          `Available commands are: ${Object.keys(commands).join(', ')}`,
      );
      respond(invalidMessage(id));
    }
  });
}