mrDoctorWho/vk4xmpp

##   plugin.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: plugin.py, v1.0 2013/10/21 alkorgun Exp $

"""
Provides library with all Non-SASL and SASL authentication mechanisms.
Can be used both for client and transport authentication.
"""

class PlugIn:
    """
    Common xmpppy plugins infrastructure: plugging in/out, debugging.
    """
    def __init__(self):
        self._exported_methods = []
        self.DBG_LINE = self.__class__.__name__.lower()

    def PlugIn(self, owner):
        """
        Attach to main instance and register ourself and all our staff in it.
        """
        self._owner = owner
        if self.DBG_LINE not in owner.debug_flags:
            owner.debug_flags.append(self.DBG_LINE)
        self.DEBUG("Plugging %s into %s" % (self, self._owner), "start")
        if hasattr(owner, self.__class__.__name__):
            return self.DEBUG("Plugging ignored: another instance already plugged.", "error")
        self._old_owners_methods = []
        for method in self._exported_methods:
            if hasattr(owner, method.__name__):
                self._old_owners_methods.append(getattr(owner, method.__name__))
            setattr(owner, method.__name__, method)
        setattr(owner, self.__class__.__name__, self)
        if hasattr(self, "plugin"):
            return self.plugin(owner)

    def PlugOut(self):
        """
        Unregister all our staff from main instance and detach from it.
        """
        self.DEBUG("Plugging %s out of %s." % (self, self._owner), "stop")
        if hasattr(self, "plugout"):
            rn = self.plugout()
        else:
            rn = None
        self._owner.debug_flags.remove(self.DBG_LINE)
        for method in self._exported_methods:
            delattr(self._owner, method.__name__)
        for method in self._old_owners_methods:
            setattr(self._owner, method.__name__, method)
        delattr(self._owner, self.__class__.__name__)
        return rn

    def DEBUG(self, text, severity="info"):
        """
        Feed a provided debug line to main instance's debug facility along with our ID string.
        """
        self._owner.DEBUG(self.DBG_LINE, text, severity)