Future runCommand()

in lib/command_runner.dart [151:210]
46 lines of code
11 McCabe index (conditional complexity)

  Future<T?> runCommand(ArgResults topLevelResults) async {
    var argResults = topLevelResults;
    var commands = _commands;
    Command? command;
    var commandString = executableName;

    while (commands.isNotEmpty) {
      if (argResults.command == null) {
        if (argResults.rest.isEmpty) {
          if (command == null) {
            // No top-level command was chosen.
            printUsage();
            return null;
          }

          command.usageException('Missing subcommand for "$commandString".');
        } else {
          var requested = argResults.rest[0];

          // Build up a help message containing similar commands, if found.
          var similarCommands =
              _similarCommandsText(requested, commands.values);

          if (command == null) {
            usageException(
                'Could not find a command named "$requested".$similarCommands');
          }

          command.usageException('Could not find a subcommand named '
              '"$requested" for "$commandString".$similarCommands');
        }
      }

      // Step into the command.
      argResults = argResults.command!;
      command = commands[argResults.name]!;
      command._globalResults = topLevelResults;
      command._argResults = argResults;
      commands = command._subcommands as Map<String, Command<T>>;
      commandString += ' ${argResults.name}';

      if (argResults.options.contains('help') && argResults['help']) {
        command.printUsage();
        return null;
      }
    }

    if (topLevelResults['help']) {
      command!.printUsage();
      return null;
    }

    // Make sure there aren't unexpected arguments.
    if (!command!.takesArguments && argResults.rest.isNotEmpty) {
      command.usageException(
          'Command "${argResults.name}" does not take any arguments.');
    }

    return (await command.run()) as T?;
  }