gajim-plural/src/common/xmpp/client.py

##   client.py
##
##   Copyright (C) 2003-2005 Alexey "Snake" Nezhdanov
##
##   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, 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.

# $Id: client.py,v 1.52 2006/01/02 19:40:55 normanr Exp $

'''
Provides PlugIn class functionality to develop extentions for xmpppy.
'''

import logging
log = logging.getLogger('gajim.c.x.plugin')

class PlugIn:
	'''
	Abstract xmpppy plugin infrastructure code, providing plugging in/out and 
	debugging functionality.

	Inherit to develop pluggable objects. No code change on the owner class
	required (the object where we plug into)
	'''
	def __init__(self):
		self._exported_methods=[]

	def PlugIn(self, owner):
		'''
		Attach to owner and register ourself and our _exported_methods in it.
		If defined by a subclass, call self.plugin(owner) to execute hook 
		code after plugging.
		'''
		self._owner=owner
		log.info('Plugging %s __INTO__ %s' % (self, self._owner))
		if self.__class__.__name__ in owner.__dict__:
			log.debug('Plugging ignored: another instance already plugged.')
			return
		self._old_owners_methods=[]
		for method in self._exported_methods:
			if method.__name__ in owner.__dict__:
				self._old_owners_methods.append(owner.__dict__[method.__name__])
			owner.__dict__[method.__name__]=method
		if self.__class__.__name__.endswith('Dispatcher'):
			# FIXME: I need BOSHDispatcher or XMPPDispatcher on .Dispatcher
			# there must be a better way..
			owner.__dict__['Dispatcher']=self
		else:
			owner.__dict__[self.__class__.__name__]=self
		
		# Execute hook
		if hasattr(self,'plugin'):
			return self.plugin(owner)

	def PlugOut(self):
		'''
		Unregister our _exported_methods from owner and detach from it.
		If defined by a subclass, call self.plugout() after unplugging to execute
		hook code.
		'''
		log.info('Plugging %s __OUT__ of %s.' % (self, self._owner))
		for method in self._exported_methods:
			del self._owner.__dict__[method.__name__]
		for method in self._old_owners_methods:
			self._owner.__dict__[method.__name__]=method
		# FIXME: Dispatcher workaround
		if self.__class__.__name__.endswith('Dispatcher'):
			del self._owner.__dict__['Dispatcher']
		else:
			del self._owner.__dict__[self.__class__.__name__]
		# Execute hook
		if hasattr(self,'plugout'):
			return self.plugout()
		del self._owner

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