| # Copyright (c) 2012 The Chromium OS Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| |
| """Module that contains meta-logic related to Cros Commands. |
| |
| This module contains two important definitions used by all commands. |
| |
| CrosCommand: The parent class of all cros commands. |
| CommandDecorator: Decorator that must be used to ensure that the command shows |
| up in _commands and is discoverable by cros. |
| """ |
| |
| from __future__ import print_function |
| |
| |
| _commands = dict() |
| |
| |
| class InvalidCommandError(Exception): |
| """Error that occurs when command class fails sanity checks.""" |
| pass |
| |
| |
| def CommandDecorator(command_name): |
| """Decorator that sanity checks and adds class to list of usable commands.""" |
| |
| def InnerCommandDecorator(original_class): |
| """"Inner Decorator that actually wraps the class.""" |
| if not hasattr(original_class, '__doc__'): |
| raise InvalidCommandError('All handlers must have docstrings: %s' % |
| original_class) |
| |
| if not issubclass(original_class, CrosCommand): |
| raise InvalidCommandError('All Commands must derive from CrosCommand: ' |
| '%s' % original_class) |
| |
| _commands[command_name] = original_class |
| original_class.command_name = command_name |
| |
| return original_class |
| |
| return InnerCommandDecorator |
| |
| |
| class CrosCommand(object): |
| """All CrosCommands must derive from this class. |
| |
| This class provides the abstract interface for all Cros Commands. When |
| designing a new command, you must sub-class from this class and use the |
| CommandDecorator decorator. You must specify a class docstring as that will be |
| used as the usage for the sub-command. |
| |
| In addition your command should implement AddParser which is passed in a |
| parser that you can add your own custom arguments. See argparse for more |
| information. |
| """ |
| # Indicates whether command stats should be uploaded for this command. |
| # Override to enable command stats uploading. |
| upload_stats = False |
| # We set the default timeout to 1 second, to prevent overly long waits for |
| # commands to complete. From manual tests, stat uploads usually take |
| # between 0.35s-0.45s in MTV. |
| upload_stats_timeout = 1 |
| |
| # Indicates whether command uses cache related commandline options. |
| use_caching_options = False |
| |
| def __init__(self, options): |
| self.options = options |
| |
| @classmethod |
| def AddParser(cls, parser): |
| """Add arguments for this command to the parser.""" |
| parser.set_defaults(cros_class=cls) |
| |
| def Run(self): |
| """The command to run.""" |
| raise NotImplementedError() |