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#!/usr/bin/env python

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# -*- coding: utf-8 -*-

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#

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#Copyright (C) 2007: Edouard TISSERANT and Laurent BESSARD

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#

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#See COPYING file for copyrights details.

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#

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#This library is free software; you can redistribute it and/or

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#modify it under the terms of the GNU General Public

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#License as published by the Free Software Foundation; either

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#version 2.1 of the License, or (at your option) any later version.

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#

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#This library 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 GNU

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#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

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#License along with this library; if not, write to the Free Software

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#Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

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import Pyro.core as pyro

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from Pyro.errors import PyroError

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import traceback

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from time import sleep

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def PYRO_connector_factory(uri, pluginsroot):

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    """

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    This returns the connector to Pyro style PLCobject

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    """

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    pluginsroot.logger.write("Connecting to URI : %s\n"%uri)

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    servicetype, location = uri.split("://")

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    # Try to get the proxy object

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    try :

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        RemotePLCObjectProxy = pyro.getAttrProxyForURI("PYROLOC://"+location+"/PLCObject")

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    except Exception, msg:

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        pluginsroot.logger.write_error("Wrong URI, please check it !\n")

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        pluginsroot.logger.write_error(traceback.format_exc())

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        return None

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    def PyroCatcher(func, default=None):

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        """

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        A function that catch a pyro exceptions, write error to logger

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        and return defaul value when it happen

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        """

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        def cather_func(*args,**kwargs):

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            try:

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                return func(*args,**kwargs)

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            except PyroError,e:

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                #pluginsroot.logger.write_error(traceback.format_exc())

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                pluginsroot.logger.write_error(str(e))

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                pluginsroot._Disconnect()

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                return default

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        return cather_func

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    # Check connection is effective. 

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    # lambda is for getattr of GetPLCstatus to happen inside catcher

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    if PyroCatcher(lambda:RemotePLCObjectProxy.GetPLCstatus())() == None:

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        pluginsroot.logger.write_error("Cannot get PLC status - connection failed.\n")

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        return None

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    class PyroProxyProxy:

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        """

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        A proxy proxy class to handle Beremiz Pyro interface specific behavior.

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        And to put pyro exception catcher in between caller and pyro proxy

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        """

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        def GetPyroProxy(self):

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            """

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            This func returns the real Pyro Proxy.

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            Use this if you musn't keep reference to it.

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            """

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            return RemotePLCObjectProxy

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        def __getattr__(self, attrName):

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            if not self.__dict__.has_key(attrName):

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                if attrName=="StartPLC":

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                    def _StartPLC():

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                        """

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                        pluginsroot._connector.GetPyroProxy() is used 

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                        rather than RemotePLCObjectProxy because

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                        object is recreated meanwhile, 

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                        so we must not keep ref to it here

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                        """

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                        if pluginsroot._connector.GetPyroProxy().GetPLCstatus() == "Dirty":

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                            """

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                            Some bad libs with static symbols may polute PLC

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                            ask runtime to suicide and come back again

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                            """

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                            pluginsroot.logger.write("Force runtime reload\n")

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                            pluginsroot._connector.GetPyroProxy().ForceReload()

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                            pluginsroot._Disconnect()

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                            # let remote PLC time to resurect.(freeze app)

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                            sleep(0.5)

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                            pluginsroot._Connect()

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                        return pluginsroot._connector.GetPyroProxy().StartPLC()

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                    member = PyroCatcher(_StartPLC, False)

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                else:

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                    def my_local_func(*args,**kwargs):

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                        return RemotePLCObjectProxy.__getattr__(attrName)(*args,**kwargs)

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                    member = PyroCatcher(my_local_func, None)

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                self.__dict__[attrName] = member

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            return self.__dict__[attrName]

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    return PyroProxyProxy()

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