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# Commandant is a framework for building command-oriented tools.
# Copyright (C) 2009-2010 Jamshed Kakar.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
"""Infrastructure extends C{bzrlib.commands.Command} to support executables."""
import os
import sys
from twisted.internet.defer import Deferred
from bzrlib.commands import Command
class ExecutableCommand(Command):
"""Specialized command runs an executable program."""
path = None
def run_argv_aliases(self, argv, alias_argv=None):
"""
Disable proper handling of argv and aliases so that arguments can be
passed directly to the executable.
"""
self.run(argv)
def run(self, argv):
"""
Run the executable, passing whatever arguments were passed to the
command.
"""
if argv:
os.system("%s %s" % (self.path, " ".join(argv)))
else:
os.system(self.path)
class TwistedCommand(Command):
"""A command that runs with a Twisted reactor."""
_return_value = None
_failure_value = None
def get_reactor(self):
"""Get the Twisted reactor to use when running this command."""
from twisted.internet import reactor
return reactor
def run_argv_aliases(self, argv, alias_argv=None):
"""Start a reactor for the command to run in."""
self._start_reactor(argv, alias_argv)
if self._failure_value is not None:
type, value, traceback = self._failure_value
raise type, value, traceback
return self._return_value
def _start_reactor(self, argv, alias_argv):
"""Start a reactor and queue a call to run the command."""
reactor = self.get_reactor()
reactor.callLater(0, self._run_command, argv, alias_argv)
reactor.run()
return self._return_value
def _run_command(self, argv, alias_argv):
"""Run the command and stop the reactor when it completes."""
subclass = super(TwistedCommand, self)
try:
result = subclass.run_argv_aliases(argv, alias_argv)
except:
self._failure_value = sys.exc_info()
return self._stop_reactor(self._failure_value)
else:
return self._stop_reactor(result)
def _capture_return_value(self, result):
"""Store the return value after running the command."""
self._return_value = result
def _capture_failure_value(self, failure):
"""Store the failure value after running the command."""
self._failure_value = (failure.type, failure.value, failure.tb)
def _stop_reactor(self, result):
"""Stop the reactor."""
reactor = self.get_reactor()
if isinstance(result, Deferred):
result.addErrback(self._capture_failure_value)
result.addCallback(self._capture_return_value)
# Use callLater to stop the reactor so that application code can
# add callbacks to the Deferred after its been returned by the run
# method.
result.addCallback(
lambda ignored: reactor.callLater(0, reactor.stop))
else:
self._capture_return_value(result)
reactor.callLater(0, reactor.stop)
def run(self):
"""Actually run the command.
This method is invoked inside a running Twisted reactor, with the
options and arguments bound to keyword parameters.
Return a C{Deferred} or None if the command was successful. It's okay
for this method to allow an exception to raise up.
"""
raise NotImplementedError("Command '%r' needs to be implemented."
% self.name())
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