d82f48a42f
This means help will always be handled by the root command. Additionally this adds an exit helper.
158 lines
4.7 KiB
Python
158 lines
4.7 KiB
Python
import argparse
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import collections
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import os
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import sys
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class CommandError(Exception):
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def __init__(self, message, usage=None):
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self.message = message
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self.usage = usage
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def __str__(self):
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return '%s\n\nerror: %s' % (self.usage, self.message)
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class ArgumentParser(argparse.ArgumentParser):
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def error(self, message):
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raise CommandError(message)
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class _HelpError(Exception):
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"""Internal exception used to trigger help code path."""
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class _HelpAction(argparse.Action):
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def __init__(self, option_strings, dest=None, help=None):
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super(_HelpAction, self).__init__(
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option_strings=option_strings,
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dest=dest or argparse.SUPPRESS,
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default=argparse.SUPPRESS,
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nargs=0,
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help=help)
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def __call__(self, parser, namespace, values, option_string=None):
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raise _HelpError()
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class Command(object):
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def __init__(self):
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self._children = collections.OrderedDict()
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self._arguments = []
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self._defaults = {}
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def _build(self):
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actions = []
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parser = ArgumentParser(add_help=False)
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parser.register('action', 'help', _HelpAction)
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for args, kwargs in self._arguments:
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actions.append(parser.add_argument(*args, **kwargs))
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parser.add_argument('_args', nargs=argparse.REMAINDER,
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help=argparse.SUPPRESS)
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return parser, actions
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def add_child(self, name, command):
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self._children[name] = command
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def add_argument(self, *args, **kwargs):
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self._arguments.append((args, kwargs))
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def set_defaults(self, **kwargs):
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self._defaults.update(kwargs)
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def exit(self, return_code):
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sys.exit(return_code)
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def format_usage(self, prog=None):
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actions = self._build()[1]
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prog = prog or os.path.basename(sys.argv[0])
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return self._usage(actions, prog) + '\n'
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def _usage(self, actions, prog):
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formatter = argparse.HelpFormatter(prog)
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formatter.add_usage(None, actions, [])
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return formatter.format_help().strip()
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def format_help(self, prog=None):
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actions = self._build()[1]
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prog = prog or os.path.basename(sys.argv[0])
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formatter = argparse.HelpFormatter(prog)
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formatter.add_usage(None, actions, [])
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if self.__doc__:
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formatter.add_text(self.__doc__)
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if actions:
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formatter.add_text('OPTIONS:')
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formatter.start_section(None)
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formatter.add_arguments(actions)
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formatter.end_section()
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subhelp = []
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for name, child in self._children.items():
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child._subhelp(name, subhelp)
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if subhelp:
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formatter.add_text('COMMANDS:')
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subhelp.insert(0, '')
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return formatter.format_help() + '\n'.join(subhelp)
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def _subhelp(self, name, result):
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actions = self._build()[1]
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if self.__doc__ or actions:
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formatter = argparse.HelpFormatter(name)
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formatter.add_usage(None, actions, [], '')
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formatter.start_section(None)
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formatter.add_text(self.__doc__)
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formatter.start_section(None)
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formatter.add_arguments(actions)
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formatter.end_section()
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formatter.end_section()
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result.append(formatter.format_help())
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for childname, child in self._children.items():
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child._subhelp(' '.join((name, childname)), result)
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def parse(self, args, prog=None):
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prog = prog or os.path.basename(sys.argv[0])
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try:
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return self._parse(
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args, argparse.Namespace(), self._defaults.copy(), prog)
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except _HelpError:
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print self.format_help(prog)
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self.exit(0)
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def _parse(self, args, namespace, defaults, prog):
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defaults.update(self._defaults)
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parser, actions = self._build()
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try:
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result = parser.parse_args(args, namespace)
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except CommandError as e:
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e.usage = self._usage(actions, prog)
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raise
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if not result._args:
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for attr, value in defaults.items():
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if not hasattr(result, attr):
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setattr(result, attr, value)
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delattr(result, '_args')
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result.command = self
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return result
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child = result._args.pop(0)
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if child not in self._children:
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raise CommandError('unrecognized command: %s' % child,
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usage=self._usage(actions, prog))
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return self._children[child]._parse(
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result._args, result, defaults, ' '.join([prog, child]))
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def run(self, *args, **kwargs):
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raise NotImplementedError
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