2005-11-07 Robert McQueen <robot101@debian.org>

	* python/_dbus.py: Add WeakReferenceDictionary cache of dbus.Bus
	instances to stop madness of creating new instances representing
	the same bus connection all the time, rendering any tracking of
	match rules and bus names quite meaningless. Caught a bug where
	the private argument to SessionBus() and friends was being passed
	in as use_default_mainloop by mistake. Still some problems with
	multiple dbus_binding.Connection instances representing the same
	low-level connection (eg when you use both SessionBus() and
	StarterBus() in same process), but it's a lot better now than it
	was.

	* python/dbus_bindings.pyx: Add constants with the return values
	for bus_request_name().

	* python/service.py: Store bus name instances in a per-dbus.Bus cache
	and retrieve the same instances for the same name, so deletion can be
	done with refcounting. Also now throws some kind of error if you
	don't actually get the name you requested, unlike previously...

	* test/python/test-client.py: Add tests for instance caching of buses
	and bus name objects.

1 files changed, 52 insertions, 10 deletions

diff --git a/python/service.py b/python/service.py
index 14a2d6d3..d1973b04 100644
--- a/python/service.py
+++ b/python/service.py
@@ -6,19 +6,60 @@ from exceptions import UnknownMethodException
 from decorators import method
 from decorators import signal
 
-class BusName:
+class BusName(object):
     """A base class for exporting your own Named Services across the Bus
     """
-    def __init__(self, named_service, bus=None):
-        self._named_service = named_service
-                             
+    def __new__(cls, name, bus=None):
+        # get default bus
         if bus == None:
-            # Get the default bus
-            self._bus = _dbus.Bus()
+            bus = _dbus.Bus()
+
+        # see if this name is already defined, return it if so
+        if name in bus._bus_names:
+            return bus._bus_names[name]
+
+        # otherwise register the name
+        retval = dbus_bindings.bus_request_name(bus.get_connection(), name)
+        print retval
+        # TODO: more intelligent tracking of bus name states?
+        if retval == dbus_bindings.REQUEST_NAME_REPLY_PRIMARY_OWNER:
+            pass
+        elif retval == dbus_bindings.REQUEST_NAME_REPLY_IN_QUEUE:
+            # you can't arrive at this state via the high-level bindings
+            # because you can't put flags in, but... who knows?
+            print "joined queue for %s" % name
+            pass
+        elif retval == dbus_bindings.REQUEST_NAME_REPLY_EXISTS:
+            raise dbus_bindings.DBusException('requested name %s already exists' % name)
+        elif retval == dbus_bindings.REQUEST_NAME_REPLY_ALREADY_OWNER:
+            # if this is a shared bus which is being used by someone
+            # else in this process, this can happen legitimately
+            print "already owner of %s" % name
+            pass
         else:
-            self._bus = bus
+            raise dbus_bindings.DBusException('requesting name %s returned unexpected value %s' % (name, retval))
 
-        dbus_bindings.bus_request_name(self._bus.get_connection(), named_service)
+        # and create the object
+        bus_name = object.__new__(cls)
+        bus_name._bus = bus
+        bus_name._name = name
+
+        # cache instance
+        bus._bus_names[name] = bus_name
+
+        return bus_name
+
+    # do nothing because this is called whether or not the bus name
+    # object was retrieved from the cache or created new
+    def __init__(self, *args, **keywords):
+        pass
+
+    # we can delete the low-level name here because these objects
+    # are guaranteed to exist only once for each bus name
+    def __del__(self):
+        # FIXME: we don't have this function yet :)
+        #dbus_bindings.bus_release_name(self._bus.get_connection(), self._named_service)
+        pass
 
     def get_bus(self):
         """Get the Bus this Service is on"""
@@ -26,10 +67,10 @@ class BusName:
 
     def get_name(self):
         """Get the name of this service"""
-        return self._named_service
+        return self._name
 
     def __repr__(self):
-        return '<dbus.service.BusName %s on %r at %#x>' % (self._named_service, self._bus, id(self))
+        return '<dbus.service.BusName %s on %r at %#x>' % (self._name, self._bus, id(self))
     __str__ = __repr__
 
 
@@ -322,3 +363,4 @@ class Object(Interface):
     def __repr__(self):
         return '<dbus.service.Object %s on %r at %#x>' % (self._object_path, self._name, id(self))
     __str__ = __repr__
+