pyatspi/base.py

   1 #Copyright (C) 2008 Codethink Ltd
   2
   3 #This library is free software; you can redistribute it and/or
   4 #modify it under the terms of the GNU Lesser General Public
   5 #License version 2 as published by the Free Software Foundation.
   6
   7 #This program is distributed in the hope that it will be useful,
   8 #but WITHOUT ANY WARRANTY; without even the implied warranty of
   9 #MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10 #GNU General Public License for more details.
  11 #You should have received a copy of the GNU Lesser General Public License
  12 #along with this program; if not, write to the Free Software
  13 #Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  14
  15 from weakref import proxy
  16
  17 from dbus.proxies import Interface, ProxyObject
  18 from dbus.exceptions import *
  19
  20 class AccessibleObjectNoLongerExists(Exception):
  21         pass
  22
  23 #------------------------------------------------------------------------------
  24
  25 class Enum(int):
  26         def __str__(self):
  27                 return self._enum_lookup(int(self))
  28
  29 #------------------------------------------------------------------------------
  30
  31 class BaseProxy(Interface):
  32         """
  33         The base D-Bus proxy for a remote object that implements one or more
  34         of the AT-SPI interfaces.
  35
  36         This class must be further specialised as the cache stores are different
  37         for Desktop objects and other Accessible objects.
  38         """
  39
  40         def __new__(cls, *args, **kwargs):
  41                 Interface.__new__(cls, *args, **kwargs)
  42
  43                 queryable_interfaces = {
  44                         'Accessible':ATSPI_ACCESSIBLE,
  45                         'Action':ATSPI_ACTION,
  46                         'Application':ATSPI_APPLICATION,
  47                         'Collection':ATSPI_COLLECTION,
  48                         'Component':ATSPI_COMPONENT,
  49                         'Desktop':ATSPI_DESKTOP,
  50                         'Document':ATSPI_DOCUMENT,
  51                         'EditableText':ATSPI_EDITABLE_TEXT,
  52                         'Hypertext':ATSPI_HYPERTEXT,
  53                         'Hyperlink':ATSPI_HYPERLINK,
  54                         'Image':ATSPI_IMAGE,
  55                         'Selection':ATSPI_SELECTION,
  56                         'StreamableContent':ATSPI_STREAMABLE_CONTENT,
  57                         'Table':ATSPI_TABLE,
  58                         'Text':ATSPI_TEXT,
  59                         'Value':ATSPI_VALUE,
  60                 }
  61
  62                 for interface in queryable_interfaces.keys():
  63                         name = 'query%s' % interface
  64                         def new_query(self, object):
  65                                 return self.queryInterface(object, queryable_interfaces[interface])
  66                         setattr(cls, name, new_query)
  67
  68         def __init__(self, obj, cache, path, interface):
  69                 """
  70                 Create a D-Bus Proxy for an ATSPI interface.
  71
  72                 obj - The D-Bus proxy object this interface uses for D-Bus calls.
  73                 cache - Cache storing data for this object.
  74                 path - The object path of the remote object.
  75                 interface - The name of the ATSPI interface that this proxy implements.
  76                 """
  77                 Interface.__init__(self, obj, interface)
  78
  79                 self._cobj = ref(cache)
  80                 self._path = path
  81
  82                 self._pgetter = self.get_dbus_method("Get", dbus_interface="org.freedesktop.DBus.Properties")
  83                 self._psetter = self.get_dbus_method("Set", dbus_interface="org.freedesktop.DBus.Properties")
  84
  85         def __getattr__(self, *args, **kwargs):
  86                 """
  87                 The __getattr__ function must return the D-Bus method wrapped in a
  88                 method to translate exceptions.
  89                 """
  90                 # Need to throw an AccessibleObjectNoLongerExists exception
  91                 # on D-Bus error of the same type.
  92                 try:
  93                         return Interface.__getattr__(self, *args, **kwargs)
  94                 except UnknownMethodException, e:
  95                         raise NotImplementedError(e)
  96                 except DBusException, e:
  97                         raise LookupError(e)
  98
  99         @property
 100         def _cache(self):
 101                 c = self._cobj()
 102                 if not c:
 103                         raise AccessibleObjectNoLongerExits("Application has been removed")
 104
 105         @property
 106         def _data(self):
 107                 try:
 108                         data = self._cache._objects[self._path]
 109                 except KeyError:
 110                         raise AccessibleObjectNoLongerExists, 'Cache data cannot be found for path %s' % (self._path,)
 111                 return data
 112
 113         @property
 114         def interfaces(self):
 115                 return self._data.interfaces
 116
 117         def queryInterface(self, interface):
 118                 if interface in self._data.interfaces:
 119                                 return self._cache.proxyFactory(self._path, interface, dbus_obj=self._obj)
 120                 else:
 121                         raise NotImplementedError(
 122                                 "%s not supported by accessible object at path %s"
 123                                 % (interface, self.path))
 124
 125 #END----------------------------------------------------------------------------