extension.py

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# Copyright 2005, 2006  Timo Savola
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published
# by the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.

import sys
import weakref
import gobject

def load(path, name, datadir):
        '''Add PATH to module load path and import all classes matching NAME .  Call
           the init_extension function with DATADIR if the imported modules
           have one.  Extension classes are expected to register themselves
           as GObjects.'''

        origpath = sys.path

        if path:
                sys.path = [path] + sys.path

        try:
                if name.endswith('.*'):
                        pkgname = name[:-2]
                        pkg = _import(pkgname)

                        names = ['%s.%s' % (pkgname, i) for i in pkg.__all__]
                else:
                        names = [name]

                for name in names:
                        try:
                                mod = _import(name)

                                if 'init_extension' in dir(mod):
                                        mod.init_extension(datadir)

                        except Exception, e:
                                if path:
                                        pretty = '%s:%s' % (path, name)
                                else:
                                        pretty = name

                                print >>sys.stderr, 'Failed to load module %s (%s)' % (pretty, e)

        finally:
                sys.path = origpath

def _import(name):
        list = name.split('.')
        return __import__(name, globals(), locals(), list[:-1])

refs_by_class = {}

def get_children(parent):
        '''Get a list of classes that are derived from PARENT (must be a GObject).'''

        return [i.pytype for i in gobject.type_children(parent)]

def get_singleton_children(parent):
        return [get_singleton(i) for i in get_children(parent)]

def get_singleton(cls):
        if '__instance' not in dir(cls):
                cls.__instance = cls()
        return cls.__instance

def get_class(name):
        '''Get a class by its NAME (must be a GObject).'''

        gname = name.replace('.', '+')
        gtype = gobject.type_from_name(gname)
        return gtype.pytype

class Extension (gobject.GObject):
        '''Base for extension tag classes.'''

        def __init__(self):
                gobject.GObject.__init__(self)

        def destroy(self):
                '''Emits the "destroy" signal.'''
                self.emit('destroy')

gobject.type_register(Extension)
gobject.signal_new('destroy', Extension, 0, gobject.TYPE_NONE, [])

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