79 lines
2.7 KiB
Python
79 lines
2.7 KiB
Python
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#
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# queue.py: factory for creating communications channels
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#
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# Copyright (C) 2013 Red Hat, Inc. All rights reserved.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import queue
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from pyanaconda.core.string import upper_ascii, lower_ascii
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class QueueFactory(object):
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"""Constructs a new object wrapping a Queue.Queue, complete with constants
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and sending functions for each type of message that can be put into the
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queue.
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Creating a new object using this class is done like so:
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q = QueueFactory("progress")
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And then adding messages to it is done like so:
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q.addMessage("init", 0)
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q.addMessage("step", 1)
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The first call will create a new constant named PROGRESS_CODE_INIT and a
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method named send_init that takes zero arguments. The second call will
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create a new constant named PROGRESS_CODE_STEP and a method named send_step
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that takes one argument.
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Reusing names within the same class is not allowed.
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"""
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def __init__(self, name):
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self.name = name
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self.__counter = 0
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self.__names = []
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self.q = queue.Queue()
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def _makeMethod(self, constant, methodName, argc):
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# pylint: disable=unused-private-member
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def __method(*args):
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if len(args) != argc:
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raise TypeError("%s() takes exactly %d arguments (%d given)" %
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(methodName, argc, len(args)))
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self.q.put((constant, args))
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__method.__name__ = methodName
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return __method
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def addMessage(self, name, argc):
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if name in self.__names:
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raise AttributeError("%s queue already has a message named %s" % (self.name, name))
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# Add a constant.
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const_name = upper_ascii(self.name) + "_CODE_" + upper_ascii(name)
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setattr(self, const_name, self.__counter)
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self.__counter += 1
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# Add a convenience method for putting things into the queue.
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method_name = "send_" + lower_ascii(name)
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method = self._makeMethod(getattr(self, const_name), method_name, argc)
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setattr(self, method_name, method)
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self.__names.append(name)
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