106 lines
3.9 KiB
Python
106 lines
3.9 KiB
Python
#
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# Gramps - a GTK+/GNOME based genealogy program
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#
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# Copyright (C) 2009 Benny Malengier
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program 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
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# GNU 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 License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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#
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"""
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Group common stuff Gramps GUI elements must be able to do when tracking a DB:
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* connect to db signals
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* listen to db changes to update themself on relevant changes
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* determine if the GUI has become out of sync with the db
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"""
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#-------------------------------------------------------------------------
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#
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# GRAMPS modules
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#
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#-------------------------------------------------------------------------
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from gramps.gen.utils.callman import CallbackManager
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#-------------------------------------------------------------------------
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#
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# DbGUIElement class
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#
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#-------------------------------------------------------------------------
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class DbGUIElement(object):
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"""
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Most interaction with the DB should be done via the callman attribute.
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On initialization, the method :meth:`_connect_db_signals` is called.
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Inheriting objects are advised to group the setup of the callman attribute
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here.
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.. attribute callman: a :class:`.CallbackManager` object, to be used to
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track specific changes in the db and set up callbacks
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"""
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def __init__(self, database):
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self.callman = CallbackManager(database)
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self._connect_db_signals()
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def _add_db_signal(self, name, callback):
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"""
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Convenience function to add a custom db signal. The attributes are just
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passed to the callman object.
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For primary objects, use the register method of the callman attribute.
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:param name: name of the signal to connect to
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:type name: string
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:param callback: function to call when signal is emitted
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:type callback: a funtion or method with the correct signature for the
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signal
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"""
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self.callman.add_db_signal(name, callback)
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def _connect_db_signals(self):
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"""
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Convenience method that is called on initialization of DbGUIElement.
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Use this to group setup of the callman attribute.
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Also called in _change_db method
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"""
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pass
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def _cleanup_callbacks(self):
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"""
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Remove all db callbacks.
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This is done automatically on destruction of the object, but is
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normally needed earlier, calling this method does so.
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Use _change_db method if you need to remove the callbacks because the
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database has changed
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"""
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database = self.callman.database
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if database.is_open():
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#a closed database has disconnected all signals
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self.callman.disconnect_all()
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#set a new callback manager
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self.callman = CallbackManager(database)
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def _change_db(self, database):
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"""
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Change the database the GUI element works on to database.
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This removes all callbacks and all registered handles.
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:param database: the new database to connect to
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"""
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dbold = self.callman.database
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if dbold.is_open():
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#a closed database has disconnected all signals
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self.callman.disconnect_all()
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#set a new callback manager on new database
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self.callman = CallbackManager(database)
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self._connect_db_signals()
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