forked from openlp/openlp
179 lines
6.9 KiB
Python
179 lines
6.9 KiB
Python
# -*- coding: utf-8 -*-
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# vim: autoindent shiftwidth=4 expandtab textwidth=120 tabstop=4 softtabstop=4
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###############################################################################
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# OpenLP - Open Source Lyrics Projection #
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# --------------------------------------------------------------------------- #
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# Copyright (c) 2008-2016 OpenLP Developers #
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# --------------------------------------------------------------------------- #
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# This program is free software; you can redistribute it and/or modify it #
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# under the terms of the GNU General Public License as published by the Free #
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# Software Foundation; version 2 of the License. #
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# #
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# This program is distributed in the hope that it will be useful, but WITHOUT #
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or #
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# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for #
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# more details. #
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# #
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# You should have received a copy of the GNU General Public License along #
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# with this program; if not, write to the Free Software Foundation, Inc., 59 #
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# Temple Place, Suite 330, Boston, MA 02111-1307 USA #
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###############################################################################
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"""
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Provide Registry Services
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"""
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import logging
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import sys
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from openlp.core.common import trace_error_handler
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log = logging.getLogger(__name__)
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class Registry(object):
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"""
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This is the Component Registry. It is a singleton object and is used to provide a look up service for common
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objects.
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"""
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log.info('Registry loaded')
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__instance__ = None
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def __new__(cls):
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"""
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Re-implement the __new__ method to make sure we create a true singleton.
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"""
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if not cls.__instance__:
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cls.__instance__ = object.__new__(cls)
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return cls.__instance__
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@classmethod
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def create(cls):
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"""
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The constructor for the component registry providing a single registry of objects.
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"""
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log.info('Registry Initialising')
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registry = cls()
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registry.service_list = {}
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registry.functions_list = {}
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registry.working_flags = {}
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# Allow the tests to remove Registry entries but not the live system
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registry.running_under_test = 'nose' in sys.argv[0]
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registry.initialising = True
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return registry
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def get(self, key):
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"""
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Extracts the registry value from the list based on the key passed in
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:param key: The service to be retrieved.
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"""
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if key in self.service_list:
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return self.service_list[key]
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else:
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if not self.initialising:
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trace_error_handler(log)
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log.error('Service {key} not found in list'.format(key=key))
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raise KeyError('Service {key} not found in list'.format(key=key))
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def register(self, key, reference):
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"""
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Registers a component against a key.
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:param key: The service to be created this is usually a major class like "renderer" or "main_window" .
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:param reference: The service address to be saved.
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"""
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if key in self.service_list:
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trace_error_handler(log)
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log.error('Duplicate service exception {key}'.format(key=key))
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raise KeyError('Duplicate service exception {key}'.format(key=key))
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else:
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self.service_list[key] = reference
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def remove(self, key):
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"""
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Removes the registry value from the list based on the key passed in.
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:param key: The service to be deleted.
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"""
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if key in self.service_list:
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del self.service_list[key]
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def register_function(self, event, function):
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"""
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Register an event and associated function to be called
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:param event: The function description like "live_display_hide" where a number of places in the code
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will/may need to respond to a single action and the caller does not need to understand or know about the
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recipients.
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:param function: The function to be called when the event happens.
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"""
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if event in self.functions_list:
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self.functions_list[event].append(function)
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else:
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self.functions_list[event] = [function]
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def remove_function(self, event, function):
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"""
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Remove an event and associated handler
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:param event: The function description..
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:param function: The function to be called when the event happens.
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"""
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if event in self.functions_list:
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self.functions_list[event].remove(function)
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def execute(self, event, *args, **kwargs):
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"""
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Execute all the handlers associated with the event and return an array of results.
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:param event: The function to be processed
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:param args: Parameters to be passed to the function.
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:param kwargs: Parameters to be passed to the function.
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"""
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results = []
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if event in self.functions_list:
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for function in self.functions_list[event]:
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try:
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result = function(*args, **kwargs)
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if result:
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results.append(result)
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except TypeError:
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# Who has called me can help in debugging
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trace_error_handler(log)
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log.exception('Exception for function {function}'.format(function=function))
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else:
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trace_error_handler(log)
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log.error("Event {event} called but not registered".format(event=event))
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return results
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def get_flag(self, key):
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"""
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Extracts the working_flag value from the list based on the key passed in
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:param key: The flag to be retrieved.
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"""
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if key in self.working_flags:
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return self.working_flags[key]
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else:
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trace_error_handler(log)
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log.error('Working Flag {key} not found in list'.format(key=key))
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raise KeyError('Working Flag {key} not found in list'.format(key=key))
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def set_flag(self, key, reference):
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"""
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Sets a working_flag based on the key passed in.
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:param key: The working_flag to be created this is usually a major class like "renderer" or "main_window" .
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:param reference: The data to be saved.
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"""
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self.working_flags[key] = reference
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def remove_flag(self, key):
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"""
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Removes the working flags value from the list based on the key passed.
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:param key: The working_flag to be deleted.
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"""
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if key in self.working_flags:
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del self.working_flags[key]
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