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# 

# queue.py: factory for creating communications channels 

# 

# Copyright (C) 2013 Red Hat, Inc. All rights reserved. 

# 

# 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, see <http://www.gnu.org/licenses/>. 

 

import queue 

from pyanaconda.core.util import lowerASCII, upperASCII 

 

class QueueFactory(object): 

"""Constructs a new object wrapping a Queue.Queue, complete with constants 

and sending functions for each type of message that can be put into the 

queue. 

 

Creating a new object using this class is done like so: 

 

q = QueueFactory("progress") 

 

And then adding messages to it is done like so: 

 

q.addMessage("init", 0) 

q.addMessage("step", 1) 

 

The first call will create a new constant named PROGRESS_CODE_INIT and a 

method named send_init that takes zero arguments. The second call will 

create a new constant named PROGRESS_CODE_STEP and a method named send_step 

that takes one argument. 

 

Reusing names within the same class is not allowed. 

""" 

def __init__(self, name): 

self.name = name 

 

self.__counter = 0 

self.__names = [] 

 

self.q = queue.Queue() 

 

def _makeMethod(self, constant, methodName, argc): 

def __method(*args): 

if len(args) != argc: 

raise TypeError("%s() takes exactly %d arguments (%d given)" % 

(methodName, argc, len(args))) 

 

self.q.put((constant, args)) 

 

__method.__name__ = methodName 

return __method 

 

def addMessage(self, name, argc): 

if name in self.__names: 

raise AttributeError("%s queue already has a message named %s" % (self.name, name)) 

 

# Add a constant. 

const_name = upperASCII(self.name) + "_CODE_" + upperASCII(name) 

setattr(self, const_name, self.__counter) 

self.__counter += 1 

 

# Add a convenience method for putting things into the queue. 

method_name = "send_" + lowerASCII(name) 

method = self._makeMethod(getattr(self, const_name), method_name, argc) 

setattr(self, method_name, method) 

 

self.__names.append(name)