The Wombat now keeps track of which categories are present in the objects

2001-07-31  Federico Mena Quintero  <federico@ximian.com>

	The Wombat now keeps track of which categories are present in the
	objects of a calendar.  It will notify the clients of changes in
	this set.  This is to make the category drop-down menus in the
	calendar/tasks views be always up to date.

	* idl/evolution-calendar.idl (Listener): Added a
	notifyCategoriesChanged() method.  The Wombat now keeps track of
	the categories within a calendar.

	* cal-client/cal-listener.[ch]: Switched it to use BonoboXObject.
	Also added the notifyCategoriesChanged implementation.

	* cal-client/cal-client.[ch]: Added a "categories_changed" signal.

	* pcs/cal-backend-file.c: Maintain a list of the live categories.
	(update_categories_from_comp): New function to maintain the set of
	live categories.
	(add_component): Update the set of categories.
	(remove_component): Likewise.
	(open_cal): Notify about changes in the set of categories.
	(create_cal): Likewise.
	(cal_backend_file_update_objects): Likewise.
	(cal_backend_file_remove_object): Likewise.
	(notify_categories_changed): New function to notify the clients
	about the current set of categories.

	* pcs/cal.c (cal_notify_categories_changed): New function.

svn path=/trunk/; revision=11536

9 files changed, 339 insertions, 155 deletions

diff --git a/calendar/ChangeLog b/calendar/ChangeLog
index f5e999af8d..ef7b73a460 100644
--- a/calendar/ChangeLog
+++ b/calendar/ChangeLog
@@ -1,3 +1,33 @@
+2001-07-31  Federico Mena Quintero  <federico@ximian.com>
+
+	The Wombat now keeps track of which categories are present in the
+	objects of a calendar.  It will notify the clients of changes in
+	this set.  This is to make the category drop-down menus in the
+	calendar/tasks views be always up to date.
+
+	* idl/evolution-calendar.idl (Listener): Added a
+	notifyCategoriesChanged() method.  The Wombat now keeps track of
+	the categories within a calendar.
+
+	* cal-client/cal-listener.[ch]: Switched it to use BonoboXObject.
+	Also added the notifyCategoriesChanged implementation.
+
+	* cal-client/cal-client.[ch]: Added a "categories_changed" signal.
+
+	* pcs/cal-backend-file.c: Maintain a list of the live categories.
+	(update_categories_from_comp): New function to maintain the set of
+	live categories.
+	(add_component): Update the set of categories.
+	(remove_component): Likewise.
+	(open_cal): Notify about changes in the set of categories.
+	(create_cal): Likewise.
+	(cal_backend_file_update_objects): Likewise.
+	(cal_backend_file_remove_object): Likewise.
+	(notify_categories_changed): New function to notify the clients
+	about the current set of categories.
+
+	* pcs/cal.c (cal_notify_categories_changed): New function.
+
 2001-07-31  Rodrigo Moya <rodrigo@ximian.com>
 
         * gui/e-day-view.c (selection_received):
diff --git a/calendar/cal-client/cal-client.c b/calendar/cal-client/cal-client.c
index 007466ddad..bb888e6205 100644
--- a/calendar/cal-client/cal-client.c
+++ b/calendar/cal-client/cal-client.c
@@ -71,6 +71,7 @@ enum {
 	CAL_OPENED,
 	OBJ_UPDATED,
 	OBJ_REMOVED,
+	CATEGORIES_CHANGED,
 	FORGET_PASSWORD,
 	LAST_SIGNAL
 };
@@ -160,6 +161,14 @@ cal_client_class_init (CalClientClass *class)
 				gtk_marshal_NONE__STRING,
 				GTK_TYPE_NONE, 1,
 				GTK_TYPE_STRING);
+	cal_client_signals[CATEGORIES_CHANGED] =
+		gtk_signal_new ("categories_changed",
+				GTK_RUN_FIRST,
+				object_class->type,
+				GTK_SIGNAL_OFFSET (CalClientClass, categories_changed),
+				gtk_marshal_NONE__POINTER,
+				GTK_TYPE_NONE, 1,
+				GTK_TYPE_POINTER);
 	cal_client_signals[FORGET_PASSWORD] =
 		gtk_signal_new ("forget_password",
 				GTK_RUN_FIRST,
@@ -171,6 +180,12 @@ cal_client_class_init (CalClientClass *class)
 
 	gtk_object_class_add_signals (object_class, cal_client_signals, LAST_SIGNAL);
 
+	class->cal_opened = NULL;
+	class->obj_updated = NULL;
+	class->obj_removed = NULL;
+	class->categories_changed = NULL;
+	class->forget_password = NULL;
+
 	object_class->destroy = cal_client_destroy;
 }
 
@@ -455,6 +470,28 @@ obj_removed_cb (CalListener *listener, const GNOME_Evolution_Calendar_CalObjUID
 	gtk_signal_emit (GTK_OBJECT (client), cal_client_signals[OBJ_REMOVED], uid);
 }
 
+/* Handle the categories_changed signal from the listener */
+static void
+categories_changed_cb (CalListener *listener, const GNOME_Evolution_Calendar_StringSeq *categories,
+		       gpointer data)
+{
+	CalClient *client;
+	GPtrArray *cats;
+	int i;
+
+	client = CAL_CLIENT (data);
+
+	cats = g_ptr_array_new ();
+	g_ptr_array_set_size (cats, categories->_length);
+
+	for (i = 0; i < categories->_length; i++)
+		cats->pdata[i] = categories->_buffer[i];
+
+	gtk_signal_emit (GTK_OBJECT (client), cal_client_signals[CATEGORIES_CHANGED], cats);
+
+	g_ptr_array_free (cats, TRUE);
+}
+
 /* Handle the get_password signal from the Wombatclient */
 static gchar *
 client_get_password_cb (WombatClient *w_client,
@@ -626,6 +663,7 @@ cal_client_open_calendar (CalClient *client, const char *str_uri, gboolean only_
 	priv->listener = cal_listener_new (cal_opened_cb,
 					   obj_updated_cb,
 					   obj_removed_cb,
+					   categories_changed_cb,
 					   client);
 	if (!priv->listener) {
 		g_message ("cal_client_open_calendar(): could not create the listener");
diff --git a/calendar/cal-client/cal-client.h b/calendar/cal-client/cal-client.h
index 4681574289..a5facbd1c6 100644
--- a/calendar/cal-client/cal-client.h
+++ b/calendar/cal-client/cal-client.h
@@ -82,6 +82,8 @@ struct _CalClientClass {
 	void (* obj_updated) (CalClient *client, const char *uid);
 	void (* obj_removed) (CalClient *client, const char *uid);
 
+	void (* categories_changed) (CalClient *client, GPtrArray *categories);
+
 	void (* forget_password) (CalClient *client, const char *key);
 };
 
diff --git a/calendar/cal-client/cal-listener.c b/calendar/cal-client/cal-listener.c
index aeeccef7dc..087d5e9c00 100644
--- a/calendar/cal-client/cal-listener.c
+++ b/calendar/cal-client/cal-listener.c
@@ -1,7 +1,6 @@
 /* Evolution calendar listener
  *
- * Copyright (C) 2000 Ximian, Inc.
- * Copyright (C) 2000 Ximian, Inc.
+ * Copyright (C) 2001 Ximian, Inc.
  *
  * Author: Federico Mena-Quintero <federico@ximian.com>
  *
@@ -26,7 +25,7 @@
 
 
 /* Private part of the CalListener structure */
-struct _CalListenerPrivate {
+struct CalListenerPrivate {
 	/* The calendar this listener refers to */
 	GNOME_Evolution_Calendar_Cal cal;
 
@@ -34,6 +33,7 @@ struct _CalListenerPrivate {
 	CalListenerCalOpenedFn cal_opened_fn;
 	CalListenerObjUpdatedFn obj_updated_fn;
 	CalListenerObjRemovedFn obj_removed_fn;
+	CalListenerCategoriesChangedFn categories_changed_fn;
 	gpointer fn_data;
 };
 
@@ -43,51 +43,28 @@ static void cal_listener_class_init (CalListenerClass *class);
 static void cal_listener_init (CalListener *listener);
 static void cal_listener_destroy (GtkObject *object);
 
-static POA_GNOME_Evolution_Calendar_Listener__vepv cal_listener_vepv;
-
-static BonoboObjectClass *parent_class;
+static void impl_notifyCalOpened (PortableServer_Servant servant,
+				  GNOME_Evolution_Calendar_Listener_OpenStatus status,
+				  GNOME_Evolution_Calendar_Cal cal,
+				  CORBA_Environment *ev);
+static void impl_notifyObjUpdated (PortableServer_Servant servant,
+				   GNOME_Evolution_Calendar_CalObjUID uid,
+				   CORBA_Environment *ev);
+static void impl_notifyObjRemoved (PortableServer_Servant servant,
+				   GNOME_Evolution_Calendar_CalObjUID uid,
+				   CORBA_Environment *ev);
+static void impl_notifyCategoriesChanged (PortableServer_Servant servant,
+					  const GNOME_Evolution_Calendar_StringSeq *categories,
+					  CORBA_Environment *ev);
+
+static BonoboXObjectClass *parent_class;
 
 
 
-/**
- * cal_listener_get_type:
- * @void:
- *
- * Registers the #CalListener class if necessary, and returns the type ID
- * associated to it.
- *
- * Return value: The type ID of the #CalListener class.
- **/
-GtkType
-cal_listener_get_type (void)
-{
-	static GtkType cal_listener_type = 0;
-
-	if (!cal_listener_type) {
-		static const GtkTypeInfo cal_listener_info = {
-			"CalListener",
-			sizeof (CalListener),
-			sizeof (CalListenerClass),
-			(GtkClassInitFunc) cal_listener_class_init,
-			(GtkObjectInitFunc) cal_listener_init,
-			NULL, /* reserved_1 */
-			NULL, /* reserved_2 */
-			(GtkClassInitFunc) NULL
-		};
-
-		cal_listener_type = gtk_type_unique (bonobo_object_get_type (), &cal_listener_info);
-	}
-
-	return cal_listener_type;
-}
-
-/* CORBA class initialization function for the calendar listener */
-static void
-init_cal_listener_corba_class (void)
-{
-	cal_listener_vepv.Bonobo_Unknown_epv = bonobo_object_get_epv ();
-	cal_listener_vepv.GNOME_Evolution_Calendar_Listener_epv = cal_listener_get_epv ();
-}
+BONOBO_X_TYPE_FUNC_FULL (CalListener,
+			 GNOME_Evolution_Calendar_Listener,
+			 BONOBO_X_OBJECT_TYPE,
+			 cal_listener);
 
 /* Class initialization function for the calendar listener */
 static void
@@ -97,11 +74,14 @@ cal_listener_class_init (CalListenerClass *class)
 
 	object_class = (GtkObjectClass *) class;
 
-	parent_class = gtk_type_class (bonobo_object_get_type ());
+	parent_class = gtk_type_class (BONOBO_X_OBJECT_TYPE);
 
-	object_class->destroy = cal_listener_destroy;
+	class->epv.notifyCalOpened = impl_notifyCalOpened;
+	class->epv.notifyObjUpdated = impl_notifyObjUpdated;
+	class->epv.notifyObjRemoved = impl_notifyObjRemoved;
+	class->epv.notifyCategoriesChanged = impl_notifyCategoriesChanged;
 
-	init_cal_listener_corba_class ();
+	object_class->destroy = cal_listener_destroy;
 }
 
 /* Object initialization function for the calendar listener */
@@ -117,6 +97,7 @@ cal_listener_init (CalListener *listener)
 	priv->cal_opened_fn = NULL;
 	priv->obj_updated_fn = NULL;
 	priv->obj_removed_fn = NULL;
+	priv->categories_changed_fn = NULL;
 }
 
 /* Destroy handler for the calendar listener */
@@ -163,12 +144,12 @@ cal_listener_destroy (GtkObject *object)
 
 /* CORBA servant implementation */
 
-/* Listener::notifyCalOpened method */
+/* ::notifyCalOpened method */
 static void
-Listener_notifyCalOpened (PortableServer_Servant servant,
-			  GNOME_Evolution_Calendar_Listener_OpenStatus status,
-			  GNOME_Evolution_Calendar_Cal cal,
-			  CORBA_Environment *ev)
+impl_notifyCalOpened (PortableServer_Servant servant,
+		      GNOME_Evolution_Calendar_Listener_OpenStatus status,
+		      GNOME_Evolution_Calendar_Cal cal,
+		      CORBA_Environment *ev)
 {
 	CalListener *listener;
 	CalListenerPrivate *priv;
@@ -199,11 +180,11 @@ Listener_notifyCalOpened (PortableServer_Servant servant,
 	(* priv->cal_opened_fn) (listener, status, cal, priv->fn_data);
 }
 
-/* Listener::notifyObjUpdated method */
+/* ::notifyObjUpdated method */
 static void
-Listener_notifyObjUpdated (PortableServer_Servant servant,
-			   GNOME_Evolution_Calendar_CalObjUID uid,
-			   CORBA_Environment *ev)
+impl_notifyObjUpdated (PortableServer_Servant servant,
+		       GNOME_Evolution_Calendar_CalObjUID uid,
+		       CORBA_Environment *ev)
 {
 	CalListener *listener;
 	CalListenerPrivate *priv;
@@ -215,11 +196,11 @@ Listener_notifyObjUpdated (PortableServer_Servant servant,
 	(* priv->obj_updated_fn) (listener, uid, priv->fn_data);
 }
 
-/* Listener::notifyObjRemoved method */
+/* ::notifyObjRemoved method */
 static void
-Listener_notifyObjRemoved (PortableServer_Servant servant,
-			   GNOME_Evolution_Calendar_CalObjUID uid,
-			   CORBA_Environment *ev)
+impl_notifyObjRemoved (PortableServer_Servant servant,
+		       GNOME_Evolution_Calendar_CalObjUID uid,
+		       CORBA_Environment *ev)
 {
 	CalListener *listener;
 	CalListenerPrivate *priv;
@@ -231,24 +212,20 @@ Listener_notifyObjRemoved (PortableServer_Servant servant,
 	(* priv->obj_removed_fn) (listener, uid, priv->fn_data);
 }
 
-/**
- * cal_listener_get_epv:
- * @void:
- *
- * Creates an EPV for the Listener CORBA class.
- *
- * Return value: A newly-allocated EPV.
- **/
-POA_GNOME_Evolution_Calendar_Listener__epv *
-cal_listener_get_epv (void)
+/* ::notifyCategoriesChanged method */
+static void
+impl_notifyCategoriesChanged (PortableServer_Servant servant,
+			      const GNOME_Evolution_Calendar_StringSeq *categories,
+			      CORBA_Environment *ev)
 {
-	POA_GNOME_Evolution_Calendar_Listener__epv *epv;
+	CalListener *listener;
+	CalListenerPrivate *priv;
+
+	listener = CAL_LISTENER (bonobo_object_from_servant (servant));
+	priv = listener->priv;
 
-	epv = g_new0 (POA_GNOME_Evolution_Calendar_Listener__epv, 1);
-	epv->notifyCalOpened  = Listener_notifyCalOpened;
-	epv->notifyObjUpdated = Listener_notifyObjUpdated;
-	epv->notifyObjRemoved = Listener_notifyObjRemoved;
-	return epv;
+	g_assert (priv->categories_changed_fn != NULL);
+	(* priv->categories_changed_fn) (listener, categories, priv->fn_data);
 }
 
 
@@ -256,27 +233,28 @@ cal_listener_get_epv (void)
 /**
  * cal_listener_construct:
  * @listener: A calendar listener.
- * @corba_listener: CORBA object for the calendar listener.
  * @cal_opened_fn: Function that will be called to notify that a calendar was
  * opened.
  * @obj_updated_fn: Function that will be called to notify that an object in the
  * calendar was updated.
  * @obj_removed_fn: Function that will be called to notify that an object in the
  * calendar was removed.
+ * @categories_changed_fn: Function that will be called to notify that the list
+ * of categories that are present in the calendar's objects has changed.
  * @fn_data: Closure data pointer that will be passed to the notification
  * functions.
  *
- * Constructs a calendar listener by binding the corresponding CORBA object to
- * it.
+ * Constructs a calendar listener by setting the callbacks that it will use for
+ * notification from the calendar server.
  *
  * Return value: the same object as the @listener argument.
  **/
 CalListener *
 cal_listener_construct (CalListener *listener,
-			GNOME_Evolution_Calendar_Listener corba_listener,
 			CalListenerCalOpenedFn cal_opened_fn,
 			CalListenerObjUpdatedFn obj_updated_fn,
 			CalListenerObjRemovedFn obj_removed_fn,
+			CalListenerCategoriesChangedFn categories_changed_fn,
 			gpointer fn_data)
 {
 	CalListenerPrivate *priv;
@@ -286,53 +264,20 @@ cal_listener_construct (CalListener *listener,
 	g_return_val_if_fail (cal_opened_fn != NULL, NULL);
 	g_return_val_if_fail (obj_updated_fn != NULL, NULL);
 	g_return_val_if_fail (obj_removed_fn != NULL, NULL);
+	g_return_val_if_fail (categories_changed_fn != NULL, NULL);
 
 	priv = listener->priv;
 
 	priv->cal_opened_fn = cal_opened_fn;
 	priv->obj_updated_fn = obj_updated_fn;
 	priv->obj_removed_fn = obj_removed_fn;
+	priv->categories_changed_fn = categories_changed_fn;
 	priv->fn_data = fn_data;
 
-	bonobo_object_construct (BONOBO_OBJECT (listener), corba_listener);
 	return listener;
 }
 
 /**
- * cal_listener_corba_object_create:
- * @object: #BonoboObject that will wrap the CORBA object.
- *
- * Creates and activates the CORBA object that is wrapped by the specified
- * calendar listener @object.
- *
- * Return value: An activated object reference or #CORBA_OBJECT_NIL in case of
- * failure.
- **/
-GNOME_Evolution_Calendar_Listener
-cal_listener_corba_object_create (BonoboObject *object)
-{
-	POA_GNOME_Evolution_Calendar_Listener *servant;
-	CORBA_Environment ev;
-
-	g_return_val_if_fail (object != NULL, CORBA_OBJECT_NIL);
-	g_return_val_if_fail (IS_CAL_LISTENER (object), CORBA_OBJECT_NIL);
-
-	servant = (POA_GNOME_Evolution_Calendar_Listener *) g_new0 (BonoboObjectServant, 1);
-	servant->vepv = &cal_listener_vepv;
-
-	CORBA_exception_init (&ev);
-	POA_GNOME_Evolution_Calendar_Listener__init ((PortableServer_Servant) servant, &ev);
-	if (ev._major != CORBA_NO_EXCEPTION) {
-		g_free (servant);
-		CORBA_exception_free (&ev);
-		return CORBA_OBJECT_NIL;
-	}
-
-	CORBA_exception_free (&ev);
-	return (GNOME_Evolution_Calendar_Listener) bonobo_object_activate_servant (object, servant);
-}
-
-/**
  * cal_listener_new:
  * @cal_opened_fn: Function that will be called to notify that a calendar was
  * opened.
@@ -340,48 +285,34 @@ cal_listener_corba_object_create (BonoboObject *object)
  * calendar was updated.
  * @obj_removed_fn: Function that will be called to notify that an object in the
  * calendar was removed.
+ * @categories_changed_fn: Function that will be called to notify that the list
+ * of categories that are present in the calendar's objects has changed.
  * @fn_data: Closure data pointer that will be passed to the notification
  * functions.
  *
  * Creates a new #CalListener object.
  *
- * Return value: A newly-created #CalListener, or NULL if its corresponding
- * CORBA object could not be created.
+ * Return value: A newly-created #CalListener object.
  **/
 CalListener *
 cal_listener_new (CalListenerCalOpenedFn cal_opened_fn,
 		  CalListenerObjUpdatedFn obj_updated_fn,
 		  CalListenerObjRemovedFn obj_removed_fn,
+		  CalListenerCategoriesChangedFn categories_changed_fn,
 		  gpointer fn_data)
 {
 	CalListener *listener;
-	CORBA_Environment ev;
-	GNOME_Evolution_Calendar_Listener corba_listener;
-	gboolean result;
 
 	g_return_val_if_fail (cal_opened_fn != NULL, NULL);
 	g_return_val_if_fail (obj_updated_fn != NULL, NULL);
 	g_return_val_if_fail (obj_removed_fn != NULL, NULL);
+	g_return_val_if_fail (categories_changed_fn != NULL, NULL);
 
 	listener = gtk_type_new (CAL_LISTENER_TYPE);
-
-	corba_listener = cal_listener_corba_object_create (BONOBO_OBJECT (listener));
-
-	CORBA_exception_init (&ev);
-	result = CORBA_Object_is_nil (corba_listener, &ev);
-	
-	if (ev._major != CORBA_NO_EXCEPTION || result) {
-		g_message ("cal_listener_new(): could not create the CORBA listener");
-		bonobo_object_unref (BONOBO_OBJECT (listener));
-		CORBA_exception_free (&ev);
-		return NULL;
-	}
-	CORBA_exception_free (&ev);
-
 	return cal_listener_construct (listener,
-				       corba_listener,
 				       cal_opened_fn,
 				       obj_updated_fn,
 				       obj_removed_fn,
+				       categories_changed_fn,
 				       fn_data);
 }
diff --git a/calendar/cal-client/cal-listener.h b/calendar/cal-client/cal-listener.h
index fa9209cc79..4cbbd8b8c9 100644
--- a/calendar/cal-client/cal-listener.h
+++ b/calendar/cal-client/cal-listener.h
@@ -1,7 +1,6 @@
 /* Evolution calendar listener
  *
- * Copyright (C) 2000 Ximian, Inc.
- * Copyright (C) 2000 Ximian, Inc.
+ * Copyright (C) 2001 Ximian, Inc.
  *
  * Author: Federico Mena-Quintero <federico@ximian.com>
  *
@@ -24,7 +23,7 @@
 #define CAL_LISTENER_H
 
 #include <libgnome/gnome-defs.h>
-#include <bonobo/bonobo-object.h>
+#include <bonobo/bonobo-xobject.h>
 #include "evolution-calendar.h"
 
 BEGIN_GNOME_DECLS
@@ -38,21 +37,20 @@ BEGIN_GNOME_DECLS
 #define IS_CAL_LISTENER(obj)         (GTK_CHECK_TYPE ((obj), CAL_LISTENER_TYPE))
 #define IS_CAL_LISTENER_CLASS(klass) (GTK_CHECK_CLASS_TYPE ((klass), CAL_LISTENER_TYPE))
 
-typedef struct _CalListener CalListener;
-typedef struct _CalListenerClass CalListenerClass;
+typedef struct CalListenerPrivate CalListenerPrivate;
 
-typedef struct _CalListenerPrivate CalListenerPrivate;
-
-struct _CalListener {
-	BonoboObject object;
+typedef struct {
+	BonoboXObject xobject;
 
 	/* Private data */
 	CalListenerPrivate *priv;
-};
+} CalListener;
+
+typedef struct {
+	BonoboXObjectClass parent_class;
 
-struct _CalListenerClass {
-	BonoboObjectClass parent_class;
-};
+	POA_GNOME_Evolution_Calendar_Listener__epv epv;
+} CalListenerClass;
 
 /* Notification functions */
 typedef void (* CalListenerCalOpenedFn) (CalListener *listener,
@@ -67,25 +65,26 @@ typedef void (* CalListenerObjRemovedFn) (CalListener *listener,
 					  const GNOME_Evolution_Calendar_CalObjUID uid,
 					  gpointer data);
 
+typedef void (* CalListenerCategoriesChangedFn) (CalListener *listener,
+						 const GNOME_Evolution_Calendar_StringSeq *categories,
+						 gpointer data);
+
 
 GtkType cal_listener_get_type (void);
 
 CalListener *cal_listener_construct (CalListener *listener,
-				     GNOME_Evolution_Calendar_Listener corba_listener,
 				     CalListenerCalOpenedFn cal_opened_fn,
 				     CalListenerObjUpdatedFn obj_updated_fn,
 				     CalListenerObjRemovedFn obj_removed_fn,
+				     CalListenerCategoriesChangedFn categories_changed_fn,
 				     gpointer fn_data);
 
-GNOME_Evolution_Calendar_Listener cal_listener_corba_object_create (BonoboObject *object);
-
 CalListener *cal_listener_new (CalListenerCalOpenedFn cal_opened_fn,
 			       CalListenerObjUpdatedFn obj_updated_fn,
 			       CalListenerObjRemovedFn obj_removed_fn,
+			       CalListenerCategoriesChangedFn categories_changed_fn,
 			       gpointer fn_data);
 
-POA_GNOME_Evolution_Calendar_Listener__epv *cal_listener_get_epv (void);
-
 
 
 END_GNOME_DECLS
diff --git a/calendar/idl/evolution-calendar.idl b/calendar/idl/evolution-calendar.idl
index ef3f59e629..7f4a850ecb 100644
--- a/calendar/idl/evolution-calendar.idl
+++ b/calendar/idl/evolution-calendar.idl
@@ -25,6 +25,9 @@ module Calendar {
 	/* A unique identifier for a calendar component */
 	typedef string CalObjUID;
 
+	/* Simple sequence of strings */
+	typedef sequence<string> StringSeq;
+
 	/* Sequence of unique identifiers */
 	typedef sequence<CalObjUID> CalObjUIDSeq;
 
@@ -212,6 +215,9 @@ module Calendar {
 
 		/* Called from a Calendar when a component is removed */
 		void notifyObjRemoved (in CalObjUID uid);
+
+		/* Called from a Calendar when the list of categories changes */
+		void notifyCategoriesChanged (in StringSeq categories);
 	};
 
 	/* Handle to a live query on a calendar */
diff --git a/calendar/pcs/cal-backend-file.c b/calendar/pcs/cal-backend-file.c
index 219683e4f9..0c87760204 100644
--- a/calendar/pcs/cal-backend-file.c
+++ b/calendar/pcs/cal-backend-file.c
@@ -29,6 +29,15 @@
 
 
 
+/* A category that exists in some of the objects of the calendar */
+typedef struct {
+	/* Category name, also used as the key in the categories hash table */
+	char *name;
+
+	/* Number of objects that have this category */
+	int refcount;
+} Category;
+
 /* Private part of the CalBackendFile structure */
 struct _CalBackendFilePrivate {
 	/* URI where the calendar data is stored */
@@ -56,6 +65,9 @@ struct _CalBackendFilePrivate {
 	GList *todos;
 	GList *journals;
 
+	/* Hash table of live categories */
+	GHashTable *categories;
+
 	/* Idle handler for saving the calendar when it is dirty */
 	guint idle_id;
 };
@@ -181,6 +193,8 @@ cal_backend_file_init (CalBackendFile *cbfile)
 	priv->events = NULL;
 	priv->todos = NULL;
 	priv->journals = NULL;
+
+	priv->categories = g_hash_table_new (g_str_hash, g_str_equal);
 }
 
 /* g_hash_table_foreach() callback to destroy a CalComponent */
@@ -247,6 +261,17 @@ save (CalBackendFile *cbfile)
 	return;
 }
 
+/* Used from g_hash_table_foreach(), frees a Category structure */
+static void
+free_category_cb (gpointer key, gpointer value, gpointer data)
+{
+	Category *c;
+
+	c = value;
+	g_free (c->name);
+	g_free (c);
+}
+
 /* Destroy handler for the file backend */
 static void
 cal_backend_file_destroy (GtkObject *object)
@@ -287,11 +312,14 @@ cal_backend_file_destroy (GtkObject *object)
 	g_list_free (priv->events);
 	g_list_free (priv->todos);
 	g_list_free (priv->journals);
-
 	priv->events = NULL;
 	priv->todos = NULL;
 	priv->journals = NULL;
 
+	g_hash_table_foreach (priv->categories, free_category_cb, NULL);
+	g_hash_table_destroy (priv->categories);
+	priv->categories = NULL;
+
 	if (priv->icalcomp) {
 		icalcomponent_free (priv->icalcomp);
 		priv->icalcomp = NULL;
@@ -465,6 +493,56 @@ check_dup_uid (CalBackendFile *cbfile, CalComponent *comp)
 	mark_dirty (cbfile);
 }
 
+/* Updates the hash table of categories by adding or removing those in the
+ * component.
+ */
+static void
+update_categories_from_comp (CalBackendFile *cbfile, CalComponent *comp, gboolean add)
+{
+	CalBackendFilePrivate *priv;
+	GSList *categories, *l;
+
+	priv = cbfile->priv;
+
+	cal_component_get_categories_list (comp, &categories);
+
+	for (l = categories; l; l = l->next) {
+		const char *name;
+		Category *c;
+
+		name = l->data;
+		c = g_hash_table_lookup (priv->categories, name);
+
+		if (add) {
+			/* Add the category to the set */
+			if (c)
+				c->refcount++;
+			else {
+				c = g_new (Category, 1);
+				c->name = g_strdup (name);
+				c->refcount = 1;
+
+				g_hash_table_insert (priv->categories, c->name, c);
+			}
+		} else {
+			/* Remove the category from the set --- it *must* have existed */
+
+			g_assert (c != NULL);
+			g_assert (c->refcount > 0);
+
+			c->refcount--;
+
+			if (c->refcount == 0) {
+				g_hash_table_remove (priv->categories, c->name);
+				g_free (c->name);
+				g_free (c);
+			}
+		}
+	}
+
+	cal_component_free_categories_list (categories);
+}
+
 /* Tries to add an icalcomponent to the file backend.  We only store the objects
  * of the types we support; all others just remain in the toplevel component so
  * that we don't lose them.
@@ -515,6 +593,10 @@ add_component (CalBackendFile *cbfile, CalComponent *comp, gboolean add_to_tople
 
 		icalcomponent_add_component (priv->icalcomp, icalcomp);
 	}
+
+	/* Update the set of categories */
+
+	update_categories_from_comp (cbfile, comp, TRUE);
 }
 
 /* Removes a component from the backend's hash and lists.  Does not perform
@@ -568,6 +650,10 @@ remove_component (CalBackendFile *cbfile, CalComponent *comp)
 	*list = g_list_remove_link (*list, l);
 	g_list_free_1 (l);
 
+	/* Update the set of categories */
+
+	update_categories_from_comp (cbfile, comp, FALSE);
+
 	gtk_object_unref (GTK_OBJECT (comp));
 }
 
@@ -607,6 +693,53 @@ scan_vcalendar (CalBackendFile *cbfile)
 	}
 }
 
+/* Used from g_hash_table_foreach(), adds a category name to the sequence */
+static void
+add_category_cb (gpointer key, gpointer value, gpointer data)
+{
+	Category *c;
+	GNOME_Evolution_Calendar_StringSeq *seq;
+
+	c = value;
+	seq = data;
+
+	seq->_buffer[seq->_length] = CORBA_string_dup (c->name);
+	seq->_length++;
+}
+
+/* Notifies the clients with the current list of categories */
+static void
+notify_categories_changed (CalBackendFile *cbfile)
+{
+	CalBackendFilePrivate *priv;
+	GNOME_Evolution_Calendar_StringSeq *seq;
+	GList *l;
+
+	priv = cbfile->priv;
+
+	/* Build the sequence of category names */
+
+	seq = GNOME_Evolution_Calendar_StringSeq__alloc ();
+	seq->_length = 0;
+	seq->_maximum = g_hash_table_size (priv->categories);
+	seq->_buffer = CORBA_sequence_CORBA_string_allocbuf (seq->_maximum);
+	CORBA_sequence_set_release (seq, TRUE);
+
+	g_hash_table_foreach (priv->categories, add_category_cb, seq);
+	g_assert (seq->_length == seq->_maximum);
+
+	/* Notify the clients */
+
+	for (l = priv->clients; l; l = l->next) {
+		Cal *cal;
+
+		cal = CAL (l->data);
+		cal_notify_categories_changed (cal, seq);
+	}
+
+	CORBA_free (seq);
+}
+
 /* Callback used from icalparser_parse() */
 static char *
 get_line_fn (char *s, size_t size, void *data)
@@ -671,6 +804,8 @@ open_cal (CalBackendFile *cbfile, GnomeVFSURI *uri, FILE *file)
 	gnome_vfs_uri_ref (uri);
 	priv->uri = uri;
 
+	notify_categories_changed (cbfile);
+
 	return CAL_BACKEND_OPEN_SUCCESS;
 }
 
@@ -692,6 +827,8 @@ create_cal (CalBackendFile *cbfile, GnomeVFSURI *uri)
 
 	mark_dirty (cbfile);
 
+	notify_categories_changed (cbfile);
+
 	return CAL_BACKEND_OPEN_SUCCESS;
 }
 
@@ -1786,6 +1923,7 @@ cal_backend_file_update_objects (CalBackend *backend, const char *calobj)
 
 	/* FIXME: do the notification asynchronously */
 	notify_update (cbfile, comp_uid);
+	notify_categories_changed (cbfile);
 
 	return TRUE;
 }
@@ -1797,6 +1935,7 @@ cal_backend_file_remove_object (CalBackend *backend, const char *uid)
 	CalBackendFile *cbfile;
 	CalBackendFilePrivate *priv;
 	CalComponent *comp;
+	int old_n_categories, new_n_categories;
 
 	cbfile = CAL_BACKEND_FILE (backend);
 	priv = cbfile->priv;
@@ -1809,12 +1948,18 @@ cal_backend_file_remove_object (CalBackend *backend, const char *uid)
 	if (!comp)
 		return FALSE;
 
+	old_n_categories = g_hash_table_size (priv->categories);
 	remove_component (cbfile, comp);
+	new_n_categories = g_hash_table_size (priv->categories);
+
 	mark_dirty (cbfile);
 
 	/* FIXME: do the notification asynchronously */
 	notify_remove (cbfile, uid);
 
+	if (old_n_categories != new_n_categories)
+		notify_categories_changed (cbfile);
+
 	return TRUE;
 }
 
diff --git a/calendar/pcs/cal.c b/calendar/pcs/cal.c
index f89d5c820f..cb92f391b5 100644
--- a/calendar/pcs/cal.c
+++ b/calendar/pcs/cal.c
@@ -674,6 +674,37 @@ cal_notify_remove (Cal *cal, const char *uid)
 }
 
 /**
+ * cal_notify_categories_changed:
+ * @cal: A calendar client interface.
+ * @categories: List of categories.
+ * 
+ * Notifies a listener attached to a calendar client interface object about the
+ * current set of categories in a calendar backend.
+ **/
+void
+cal_notify_categories_changed (Cal *cal, GNOME_Evolution_Calendar_StringSeq *categories)
+{
+	CalPrivate *priv;
+	CORBA_Environment ev;
+
+	g_return_if_fail (cal != NULL);
+	g_return_if_fail (IS_CAL (cal));
+	g_return_if_fail (categories != NULL);
+
+	priv = cal->priv;
+	g_return_if_fail (priv->listener != CORBA_OBJECT_NIL);
+
+	CORBA_exception_init (&ev);
+	GNOME_Evolution_Calendar_Listener_notifyCategoriesChanged (priv->listener, categories, &ev);
+
+	if (ev._major != CORBA_NO_EXCEPTION)
+		g_message ("cal_notify_categories_changed(): Could not notify the listener "
+			   "about the current set of categories");
+
+	CORBA_exception_free (&ev);
+}
+
+/**
  * cal_get_password:
  * @cal: A calendar client interface.
  * @prompt: The message to show to the user when asking for the password.
diff --git a/calendar/pcs/cal.h b/calendar/pcs/cal.h
index 35e870739c..6797b5df25 100644
--- a/calendar/pcs/cal.h
+++ b/calendar/pcs/cal.h
@@ -65,6 +65,8 @@ Cal *cal_new (CalBackend *backend, GNOME_Evolution_Calendar_Listener listener);
 void cal_notify_update (Cal *cal, const char *uid);
 void cal_notify_remove (Cal *cal, const char *uid);
 
+void cal_notify_categories_changed (Cal *cal, GNOME_Evolution_Calendar_StringSeq *categories);
+
 char *cal_get_password (Cal *cal, const char *prompt, const char *key);
 void  cal_forget_password (Cal *cal, const char *key);