1 # Copyright 2013 The Chromium Authors. All rights reserved. 2 # Use of this source code is governed by a BSD-style license that can be 3 # found in the LICENSE file. 4 5 """An option parser which handles the first arg as a command. 6 7 Add other nice functionality such as printing a list of commands 8 and an example in usage. 9 """ 10 11 import optparse 12 import sys 13 14 15 class CommandOptionParser(optparse.OptionParser): 16 """Wrapper class for OptionParser to help with listing commands.""" 17 18 def __init__(self, *args, **kwargs): 19 """Creates a CommandOptionParser. 20 21 Args: 22 commands_dict: A dictionary mapping command strings to an object defining 23 - add_options_func: Adds options to the option parser 24 - run_command_func: Runs the command itself. 25 example: An example command. 26 everything else: Passed to optparse.OptionParser contructor. 27 """ 28 self.commands_dict = kwargs.pop('commands_dict', {}) 29 self.example = kwargs.pop('example', '') 30 if not 'usage' in kwargs: 31 kwargs['usage'] = 'Usage: %prog <command> [options]' 32 optparse.OptionParser.__init__(self, *args, **kwargs) 33 34 #override 35 def get_usage(self): 36 normal_usage = optparse.OptionParser.get_usage(self) 37 command_list = self.get_command_list() 38 example = self.get_example() 39 return self.expand_prog_name(normal_usage + example + command_list) 40 41 #override 42 def get_command_list(self): 43 if self.commands_dict.keys(): 44 return '\nCommands:\n %s\n' % '\n '.join( 45 sorted(self.commands_dict.keys())) 46 return '' 47 48 def get_example(self): 49 if self.example: 50 return '\nExample:\n %s\n' % self.example 51 return '' 52 53 54 def ParseAndExecute(option_parser, argv=None): 55 """Parses options/args from argv and runs the specified command. 56 57 Args: 58 option_parser: A CommandOptionParser object. 59 argv: Command line arguments. If None, automatically draw from sys.argv. 60 61 Returns: 62 An exit code. 63 """ 64 if not argv: 65 argv = sys.argv 66 67 if len(argv) < 2 or argv[1] not in option_parser.commands_dict: 68 # Parse args first, if this is '--help', optparse will print help and exit 69 option_parser.parse_args(argv) 70 option_parser.error('Invalid command.') 71 72 cmd = option_parser.commands_dict[argv[1]] 73 cmd.add_options_func(option_parser) 74 options, args = option_parser.parse_args(argv) 75 return cmd.run_command_func(argv[1], options, args, option_parser) 76
