New struct to wrap instances of calendar objects for recurrencies and

2000-02-08  Federico Mena Quintero  <federico@helixcode.com>

	* evolution-calendar.idl (CalObjInstance): New struct to wrap
	instances of calendar objects for recurrencies and alarms.
	(Cal::get_events_in_range): New method to get ocurring and
	recurring events by time range.

	* cal-backend.c (cal_backend_get_events_in_range): New function to
	get a list of event instances in a time range.
	(string_from_ical_object): New internal function.
	(cal_backend_get_object): Use string_from_ical_object() instead of
	doing everything ourselves.
	(cal_backend_get_events_in_range): New function to get a list of
	the events that occur or recur in a specified time range.

	* cal-client.c (cal_client_get_events_in_range): Implemented
	client-side function.

	* cal-util.h:
	* cal-util.c: New files with utilities and types common to the
	client and server parts.
	(CalObjInstance): New structure to hold an instance of an actual
	occurrence, recurrence, or alarm trigger of a calendar object.
	(cal_obj_instance_list_free): New function to free a list of
	calendar object instances.

	* cal.c (Cal_get_events_in_range): Implemented new method.

	* corba-cal.c (cal_repo_get_updated_objects): Free `str' with
	free(), not g_free(), since calendar_get_as_vcal_string() uses
	writeMemVObject(), which uses realloc().  Fixed in gnome-pim as
	well.

svn path=/trunk/; revision=1693

17 files changed, 567 insertions, 26 deletions

diff --git a/calendar/ChangeLog b/calendar/ChangeLog
index 489b0f319c..7e5b0db773 100644
--- a/calendar/ChangeLog
+++ b/calendar/ChangeLog
@@ -1,3 +1,36 @@
+2000-02-08  Federico Mena Quintero  <federico@helixcode.com>
+
+	* evolution-calendar.idl (CalObjInstance): New struct to wrap
+	instances of calendar objects for recurrencies and alarms.
+	(Cal::get_events_in_range): New method to get ocurring and
+	recurring events by time range.
+
+	* cal-backend.c (cal_backend_get_events_in_range): New function to
+	get a list of event instances in a time range.
+	(string_from_ical_object): New internal function.
+	(cal_backend_get_object): Use string_from_ical_object() instead of
+	doing everything ourselves.
+	(cal_backend_get_events_in_range): New function to get a list of
+	the events that occur or recur in a specified time range.
+
+	* cal-client.c (cal_client_get_events_in_range): Implemented
+	client-side function.
+
+	* cal-util.h:
+	* cal-util.c: New files with utilities and types common to the
+	client and server parts.
+	(CalObjInstance): New structure to hold an instance of an actual
+	occurrence, recurrence, or alarm trigger of a calendar object.
+	(cal_obj_instance_list_free): New function to free a list of
+	calendar object instances.
+
+	* cal.c (Cal_get_events_in_range): Implemented new method.
+
+	* corba-cal.c (cal_repo_get_updated_objects): Free `str' with
+	free(), not g_free(), since calendar_get_as_vcal_string() uses
+	writeMemVObject(), which uses realloc().  Fixed in gnome-pim as
+	well.
+
 2000-02-04  Federico Mena Quintero  <federico@helixcode.com>
 
 	* cal-backend.c (get_calendar_base_vobject): New function to
diff --git a/calendar/Makefile.am b/calendar/Makefile.am
index 408f80dd76..5fa18ba0dd 100644
--- a/calendar/Makefile.am
+++ b/calendar/Makefile.am
@@ -62,6 +62,8 @@ gnomecal_SOURCES =				\
 	cal-client.h				\
 	cal-listener.c				\
 	cal-listener.h				\
+	cal-util.c				\
+	cal-util.h				\
 	calendar.c				\
 	calendar.h				\
 	calendar-conduit.h			\
@@ -134,6 +136,8 @@ tlacuache_SOURCES =				\
 	cal-common.h				\
 	cal-factory.c				\
 	cal-factory.h				\
+	cal-util.c				\
+	cal-util.h				\
 	calobj.c				\
 	calobj.h				\
 	job.c					\
diff --git a/calendar/cal-backend.c b/calendar/cal-backend.c
index 72315e3882..2039c9c400 100644
--- a/calendar/cal-backend.c
+++ b/calendar/cal-backend.c
@@ -299,6 +299,30 @@ get_calendar_base_vobject (CalBackend *backend)
 	return vobj;
 }
 
+/* Builds the string representation of a complete calendar object wrapping the
+ * specified object --- a complete calendar is needed because of the timezone
+ * information.  The return value must be freed with free(), not g_free(), since
+ * the internal implementation calls writeMemVObject() from libversit, which
+ * uses realloc() to allocate this string.
+ */
+static char *
+string_from_ical_object (CalBackend *backend, iCalObject *ico)
+{
+	VObject *vcalobj, *vobj;
+	char *buf;
+
+	vcalobj = get_calendar_base_vobject (backend);
+	vobj = ical_object_to_vobject (ico);
+	addVObjectProp (vcalobj, vobj);
+
+	buf = writeMemVObject (NULL, NULL, vcalobj);
+
+	cleanVObject (vcalobj);
+	cleanStrTbl ();
+
+	return buf;
+}
+
 
 
 /**
@@ -467,8 +491,7 @@ cal_backend_get_object (CalBackend *backend, const char *uid)
 {
 	CalBackendPrivate *priv;
 	iCalObject *ico;
-	VObject *vcalobj, *vobj;
-	char *buf;
+	char *buf, *retval;
 
 	g_return_val_if_fail (backend != NULL, NULL);
 	g_return_val_if_fail (IS_CAL_BACKEND (backend), NULL);
@@ -480,19 +503,105 @@ cal_backend_get_object (CalBackend *backend, const char *uid)
 
 	g_assert (priv->object_hash != NULL);
 
-	ico = g_hash_table_lookup (priv->objec_hash, uid);
+	ico = g_hash_table_lookup (priv->object_hash, uid);
 
 	if (!ico)
 		return NULL;
 
-	vcalobj = get_calendar_base_vobject (backend);
-	vobj = ical_object_to_vobject (ico);
-	addVObjectProp (vcalobj, vobj);
+	/* string_from_ical_object() uses writeMemVObject(), which uses
+	 * realloc(), so we must free its result with free() instead of
+	 * g_free().  We take a copy of the result so that callers can use the
+	 * normal glib function to free it.
+	 */
 
-	buf = writeMemVObject (NULL, NULL, vcalobj);
+	buf = string_from_ical_object (backend, ico);
+	retval = g_strdup (buf);
+	free (buf);
 
-	cleanVObject (vcalobj);
-	cleanStrTbl ();
+	return retval;
+}
 
-	return buf;
+struct build_event_list_closure {
+	CalBackend *backend;
+	GList *event_list;
+};
+
+/* Builds a sorted list of event object instances.  Used as a callback from
+ * ical_object_generate_events().
+ */
+static int
+build_event_list (iCalObject *ico, time_t start, time_t end, void *data)
+{
+	CalObjInstance *icoi;
+	struct build_event_list_closure *c;
+
+	c = data;
+
+	icoi = g_new (CalObjInstance, 1);
+	icoi->calobj = string_from_ical_object (c->backend, ico);
+	icoi->start = start;
+	icoi->end = end;
+
+	c->event_list = g_list_prepend (c->event_list, icoi);
+
+	return TRUE;
+}
+
+/* Compares two CalObjInstance structures by their start times.  Called from
+ * g_list_sort().
+ */
+static gint
+compare_instance_func (gconstpointer a, gconstpointer b)
+{
+	const CalObjInstance *ca, *cb;
+	time_t diff;
+
+	ca = a;
+	cb = b;
+
+	diff = ca->start - cb->start;
+	return (diff < 0) ? -1 : (diff > 0) ? 1 : 0;
+}
+
+/**
+ * cal_backend_get_events_in_range:
+ * @backend: A calendar backend.
+ * @start: Start time for query.
+ * @end: End time for query.
+ * 
+ * Builds a sorted list of calendar event object instances that occur or recur
+ * within the specified time range.  Each object instance contains the object
+ * itself and the start/end times at which it occurs or recurs.
+ * 
+ * Return value: A list of calendar event object instances, sorted by their
+ * start times.
+ **/
+GList *
+cal_backend_get_events_in_range (CalBackend *backend, time_t start, time_t end)
+{
+	CalBackendPrivate *priv;
+	struct build_event_list_closure c;
+	GList *l;
+
+	g_return_val_if_fail (backend != NULL, NULL);
+	g_return_val_if_fail (IS_CAL_BACKEND (backend), NULL);
+
+	priv = backend->priv;
+	g_return_val_if_fail (priv->loaded, NULL);
+
+	g_return_val_if_fail (start != -1 && end != -1, NULL);
+	g_return_val_if_fail (start <= end, NULL);
+
+	c.backend = backend;
+	c.event_list = NULL;
+
+	for (l = priv->events; l; l = l->next) {
+		iCalObject *ico;
+
+		ico = l->data;
+		ical_object_generate_events (ico, start, end, build_event_list, &c);
+	}
+
+	c.event_list = g_list_sort (c.event_list, compare_instance_func);
+	return c.event_list;
 }
diff --git a/calendar/cal-backend.h b/calendar/cal-backend.h
index e972cbd59e..aa54a3339d 100644
--- a/calendar/cal-backend.h
+++ b/calendar/cal-backend.h
@@ -27,6 +27,7 @@
 #include "evolution-calendar.h"
 #include "cal-common.h"
 #include "cal.h"
+#include "cal-util.h"
 
 BEGIN_GNOME_DECLS
 
@@ -39,9 +40,10 @@ BEGIN_GNOME_DECLS
 #define IS_CAL_BACKEND(obj)         (GTK_CHECK_TYPE ((obj), CAL_BACKEND_TYPE))
 #define IS_CAL_BACKEND_CLASS(klass) (GTK_CHECK_CLASS_TYPE ((klass), CAL_BACKEND_TYPE))
 
+/* Load status values */
 typedef enum {
-	CAL_BACKEND_LOAD_SUCCESS,		/* Loading OK */
-	CAL_BACKEND_LOAD_ERROR			/* We need better error reporting in libversit */
+	CAL_BACKEND_LOAD_SUCCESS,	/* Loading OK */
+	CAL_BACKEND_LOAD_ERROR		/* We need better error reporting in libversit */
 } CalBackendLoadStatus;
 
 struct _CalBackend {
@@ -68,6 +70,8 @@ CalBackendLoadStatus cal_backend_load (CalBackend *backend, GnomeVFSURI *uri);
 
 char *cal_backend_get_object (CalBackend *backend, const char *uid);
 
+GList *cal_backend_get_events_in_range (CalBackend *backend, time_t start, time_t end);
+
 
 
 END_GNOME_DECLS
diff --git a/calendar/cal-client.c b/calendar/cal-client.c
index 63d33610f6..af8b83db34 100644
--- a/calendar/cal-client.c
+++ b/calendar/cal-client.c
@@ -471,3 +471,57 @@ cal_client_get_object (CalClient *client, const char *uid)
 	CORBA_exception_free (&ev);
 	return retval;
 }
+
+GList *
+cal_client_get_events_in_range (CalClient *client, time_t start, time_t end)
+{
+	CalClientPrivate *priv;
+	CORBA_Environment ev;
+	Evolution_Calendar_CalObjInstanceSeq *seq;
+	GList *elist;
+	int i;
+
+	g_return_val_if_fail (client != NULL, NULL);
+	g_return_val_if_fail (IS_CAL_CLIENT (client), NULL);
+
+	priv = client->priv;
+	g_return_val_if_fail (priv->load_state == LOAD_STATE_LOADED, NULL);
+
+	g_return_val_if_fail (start != -1 && end != -1, NULL);
+	g_return_val_if_fail (start <= end, NULL);
+
+	priv = client->priv;
+
+	CORBA_exception_init (&ev);
+
+	seq = Evolution_Calendar_Cal_get_events_in_range (priv->cal, start, end, &ev);
+	if (ev._major != CORBA_NO_EXCEPTION) {
+		g_message ("cal_client_get_events_in_range(): could not get the event range");
+		CORBA_exception_free (&ev);
+		return NULL;
+	}
+	CORBA_exception_free (&ev);
+
+	/* Create the list in reverse order */
+
+	elist = NULL;
+
+	for (i = 0; i < seq->_length; i++) {
+		Evolution_Calendar_CalObjInstance *corba_icoi;
+		CalObjInstance *icoi;
+
+		corba_icoi = &seq->_buffer[i];
+		icoi = g_new (CalObjInstance, 1);
+
+		icoi->calobj = g_strdup (corba_icoi->calobj);
+		icoi->start = corba_icoi->start;
+		icoi->end = corba_icoi->end;
+
+		elist = g_list_prepend (elist, icoi);
+	}
+
+	CORBA_free (seq);
+	elist = g_list_reverse (elist);
+
+	return elist;
+}
diff --git a/calendar/cal-client.h b/calendar/cal-client.h
index 2f9ae5e1f8..e81ec8c13a 100644
--- a/calendar/cal-client.h
+++ b/calendar/cal-client.h
@@ -24,6 +24,7 @@
 
 #include <libgnome/gnome-defs.h>
 #include <gtk/gtkobject.h>
+#include "cal-util.h"
 
 BEGIN_GNOME_DECLS
 
@@ -73,6 +74,8 @@ gboolean cal_client_load_calendar (CalClient *client, const char *str_uri);
 
 char *cal_client_get_object (CalClient *client, const char *uid);
 
+GList *cal_client_get_events_in_range (CalClient *client, time_t start, time_t end);
+
 
 
 END_GNOME_DECLS
diff --git a/calendar/cal-client/cal-client.c b/calendar/cal-client/cal-client.c
index 63d33610f6..af8b83db34 100644
--- a/calendar/cal-client/cal-client.c
+++ b/calendar/cal-client/cal-client.c
@@ -471,3 +471,57 @@ cal_client_get_object (CalClient *client, const char *uid)
 	CORBA_exception_free (&ev);
 	return retval;
 }
+
+GList *
+cal_client_get_events_in_range (CalClient *client, time_t start, time_t end)
+{
+	CalClientPrivate *priv;
+	CORBA_Environment ev;
+	Evolution_Calendar_CalObjInstanceSeq *seq;
+	GList *elist;
+	int i;
+
+	g_return_val_if_fail (client != NULL, NULL);
+	g_return_val_if_fail (IS_CAL_CLIENT (client), NULL);
+
+	priv = client->priv;
+	g_return_val_if_fail (priv->load_state == LOAD_STATE_LOADED, NULL);
+
+	g_return_val_if_fail (start != -1 && end != -1, NULL);
+	g_return_val_if_fail (start <= end, NULL);
+
+	priv = client->priv;
+
+	CORBA_exception_init (&ev);
+
+	seq = Evolution_Calendar_Cal_get_events_in_range (priv->cal, start, end, &ev);
+	if (ev._major != CORBA_NO_EXCEPTION) {
+		g_message ("cal_client_get_events_in_range(): could not get the event range");
+		CORBA_exception_free (&ev);
+		return NULL;
+	}
+	CORBA_exception_free (&ev);
+
+	/* Create the list in reverse order */
+
+	elist = NULL;
+
+	for (i = 0; i < seq->_length; i++) {
+		Evolution_Calendar_CalObjInstance *corba_icoi;
+		CalObjInstance *icoi;
+
+		corba_icoi = &seq->_buffer[i];
+		icoi = g_new (CalObjInstance, 1);
+
+		icoi->calobj = g_strdup (corba_icoi->calobj);
+		icoi->start = corba_icoi->start;
+		icoi->end = corba_icoi->end;
+
+		elist = g_list_prepend (elist, icoi);
+	}
+
+	CORBA_free (seq);
+	elist = g_list_reverse (elist);
+
+	return elist;
+}
diff --git a/calendar/cal-client/cal-client.h b/calendar/cal-client/cal-client.h
index 2f9ae5e1f8..e81ec8c13a 100644
--- a/calendar/cal-client/cal-client.h
+++ b/calendar/cal-client/cal-client.h
@@ -24,6 +24,7 @@
 
 #include <libgnome/gnome-defs.h>
 #include <gtk/gtkobject.h>
+#include "cal-util.h"
 
 BEGIN_GNOME_DECLS
 
@@ -73,6 +74,8 @@ gboolean cal_client_load_calendar (CalClient *client, const char *str_uri);
 
 char *cal_client_get_object (CalClient *client, const char *uid);
 
+GList *cal_client_get_events_in_range (CalClient *client, time_t start, time_t end);
+
 
 
 END_GNOME_DECLS
diff --git a/calendar/cal.c b/calendar/cal.c
index 1ce1d91716..664d9ef416 100644
--- a/calendar/cal.c
+++ b/calendar/cal.c
@@ -196,6 +196,63 @@ Cal_get_object (PortableServer_Servant servant,
 	}
 }
 
+/* Cal::get_events_in_range method */
+static Evolution_Calendar_CalObjInstanceSeq *
+Cal_get_events_in_range (PortableServer_Servant servant,
+			 const Evolution_Calendar_Time_t start,
+			 const Evolution_Calendar_Time_t end,
+			 CORBA_Environment *ev)
+{
+	Cal *cal;
+	CalPrivate *priv;
+	time_t t_start, t_end;
+	Evolution_Calendar_CalObjInstanceSeq *seq;
+	GList *elist, *l;
+	int n, i;
+
+	cal = CAL (bonobo_object_from_servant (servant));
+	priv = cal->priv;
+
+	t_start = (time_t) start;
+	t_end = (time_t) end;
+
+	if (t_start > t_end || t_start == -1 || t_end == -1) {
+		CORBA_exception_set (ev, CORBA_USER_EXCEPTION,
+				     ex_Evolution_Calendar_Cal_InvalidRange,
+				     NULL);
+		return NULL;
+	}
+
+	/* Figure out the list and allocate the sequence */
+
+	elist = cal_backend_get_events_in_range (priv->backend, t_start, t_end);
+	n = g_list_length (elist);
+
+	seq = Evolution_Calendar_CalObjInstanceSeq__alloc ();
+	seq->_length = n;
+	seq->_buffer = CORBA_sequence_Evolution_Calendar_CalObjInstance_allocbuf (n);
+
+	/* Fill the sequence */
+
+	for (i = 0, l = elist; i < n; i++, l = l->next) {
+		CalObjInstance *icoi;
+		Evolution_Calendar_CalObjInstance *corba_icoi;
+
+		icoi = l->data;
+		corba_icoi = &seq->_buffer[i];
+
+		corba_icoi->calobj = CORBA_string_dup (icoi->calobj);
+		corba_icoi->start = icoi->start;
+		corba_icoi->end = icoi->end;
+	}
+
+	/* Done */
+
+	cal_obj_instance_list_free (elist);
+
+	return seq;
+}
+
 /**
  * cal_get_epv:
  * @void:
@@ -212,6 +269,7 @@ cal_get_epv (void)
 	epv = g_new0 (POA_Evolution_Calendar_Cal__epv, 1);
 	epv->_get_uri = Cal_get_uri;
 	epv->get_object = Cal_get_object;
+	epv->get_events_in_range = Cal_get_events_in_range;
 
 	return epv;
 }
diff --git a/calendar/corba-cal.c b/calendar/corba-cal.c
index 74afc0e76a..7b9878f875 100644
--- a/calendar/corba-cal.c
+++ b/calendar/corba-cal.c
@@ -295,7 +295,7 @@ cal_repo_get_updated_objects (PortableServer_Servant servant,
 	}
 	str = calendar_get_as_vcal_string (dirty_cal);
 	res = CORBA_string_dup (str);
-	g_free (str);
+	free (str); /* calendar_get_as_vcal_string() uses writeMemVObject(), which uses realloc() */
 	calendar_destroy (dirty_cal);
 
 	return res;
diff --git a/calendar/evolution-calendar.idl b/calendar/evolution-calendar.idl
index 6746eb66a1..8b9878d78e 100644
--- a/calendar/evolution-calendar.idl
+++ b/calendar/evolution-calendar.idl
@@ -23,11 +23,29 @@ module Calendar {
 	/* An unique identifier for a calendar object */
 	typedef string CalObjUID;
 
+	/* Used to store a time_t */
+	typedef unsigned long Time_t;
+
+	/* An instance of a calendar object that actually occurs.  These are
+	 * "virtual" objects in that they are used to represent instances of
+	 * recurring events and alarms.  "Real" objects just contain the
+	 * information required to figure out the times at which they recur or
+	 * trigger.  
+	 */
+	struct CalObjInstance {
+		CalObj calobj;
+		Time_t start;
+		Time_t end;
+	};
+
+	typedef sequence<CalObjInstance> CalObjInstanceSeq;
+
 	interface Listener;
 
 	/* Calendar client interface */
 	interface Cal : Bonobo::Unknown {
 		exception NotFound {};
+		exception InvalidRange {};
 
 		/* A calendar is identified by its URI */
 		readonly attribute string uri;
@@ -35,6 +53,10 @@ module Calendar {
 		/* Gets an object based on its URI */
 		CalObj get_object (in CalObjUID uid)
 			raises (NotFound);
+
+		/* Gets the events that occur or recur in the specified time range */
+		CalObjInstanceSeq get_events_in_range (in Time_t start, in Time_t end)
+			raises (InvalidRange);
 	};
 
 	/* Listener for changes in a calendar */
diff --git a/calendar/gui/Makefile.am b/calendar/gui/Makefile.am
index 408f80dd76..5fa18ba0dd 100644
--- a/calendar/gui/Makefile.am
+++ b/calendar/gui/Makefile.am
@@ -62,6 +62,8 @@ gnomecal_SOURCES =				\
 	cal-client.h				\
 	cal-listener.c				\
 	cal-listener.h				\
+	cal-util.c				\
+	cal-util.h				\
 	calendar.c				\
 	calendar.h				\
 	calendar-conduit.h			\
@@ -134,6 +136,8 @@ tlacuache_SOURCES =				\
 	cal-common.h				\
 	cal-factory.c				\
 	cal-factory.h				\
+	cal-util.c				\
+	cal-util.h				\
 	calobj.c				\
 	calobj.h				\
 	job.c					\
diff --git a/calendar/gui/corba-cal.c b/calendar/gui/corba-cal.c
index 74afc0e76a..7b9878f875 100644
--- a/calendar/gui/corba-cal.c
+++ b/calendar/gui/corba-cal.c
@@ -295,7 +295,7 @@ cal_repo_get_updated_objects (PortableServer_Servant servant,
 	}
 	str = calendar_get_as_vcal_string (dirty_cal);
 	res = CORBA_string_dup (str);
-	g_free (str);
+	free (str); /* calendar_get_as_vcal_string() uses writeMemVObject(), which uses realloc() */
 	calendar_destroy (dirty_cal);
 
 	return res;
diff --git a/calendar/idl/evolution-calendar.idl b/calendar/idl/evolution-calendar.idl
index 6746eb66a1..8b9878d78e 100644
--- a/calendar/idl/evolution-calendar.idl
+++ b/calendar/idl/evolution-calendar.idl
@@ -23,11 +23,29 @@ module Calendar {
 	/* An unique identifier for a calendar object */
 	typedef string CalObjUID;
 
+	/* Used to store a time_t */
+	typedef unsigned long Time_t;
+
+	/* An instance of a calendar object that actually occurs.  These are
+	 * "virtual" objects in that they are used to represent instances of
+	 * recurring events and alarms.  "Real" objects just contain the
+	 * information required to figure out the times at which they recur or
+	 * trigger.  
+	 */
+	struct CalObjInstance {
+		CalObj calobj;
+		Time_t start;
+		Time_t end;
+	};
+
+	typedef sequence<CalObjInstance> CalObjInstanceSeq;
+
 	interface Listener;
 
 	/* Calendar client interface */
 	interface Cal : Bonobo::Unknown {
 		exception NotFound {};
+		exception InvalidRange {};
 
 		/* A calendar is identified by its URI */
 		readonly attribute string uri;
@@ -35,6 +53,10 @@ module Calendar {
 		/* Gets an object based on its URI */
 		CalObj get_object (in CalObjUID uid)
 			raises (NotFound);
+
+		/* Gets the events that occur or recur in the specified time range */
+		CalObjInstanceSeq get_events_in_range (in Time_t start, in Time_t end)
+			raises (InvalidRange);
 	};
 
 	/* Listener for changes in a calendar */
diff --git a/calendar/pcs/cal-backend.c b/calendar/pcs/cal-backend.c
index 72315e3882..2039c9c400 100644
--- a/calendar/pcs/cal-backend.c
+++ b/calendar/pcs/cal-backend.c
@@ -299,6 +299,30 @@ get_calendar_base_vobject (CalBackend *backend)
 	return vobj;
 }
 
+/* Builds the string representation of a complete calendar object wrapping the
+ * specified object --- a complete calendar is needed because of the timezone
+ * information.  The return value must be freed with free(), not g_free(), since
+ * the internal implementation calls writeMemVObject() from libversit, which
+ * uses realloc() to allocate this string.
+ */
+static char *
+string_from_ical_object (CalBackend *backend, iCalObject *ico)
+{
+	VObject *vcalobj, *vobj;
+	char *buf;
+
+	vcalobj = get_calendar_base_vobject (backend);
+	vobj = ical_object_to_vobject (ico);
+	addVObjectProp (vcalobj, vobj);
+
+	buf = writeMemVObject (NULL, NULL, vcalobj);
+
+	cleanVObject (vcalobj);
+	cleanStrTbl ();
+
+	return buf;
+}
+
 
 
 /**
@@ -467,8 +491,7 @@ cal_backend_get_object (CalBackend *backend, const char *uid)
 {
 	CalBackendPrivate *priv;
 	iCalObject *ico;
-	VObject *vcalobj, *vobj;
-	char *buf;
+	char *buf, *retval;
 
 	g_return_val_if_fail (backend != NULL, NULL);
 	g_return_val_if_fail (IS_CAL_BACKEND (backend), NULL);
@@ -480,19 +503,105 @@ cal_backend_get_object (CalBackend *backend, const char *uid)
 
 	g_assert (priv->object_hash != NULL);
 
-	ico = g_hash_table_lookup (priv->objec_hash, uid);
+	ico = g_hash_table_lookup (priv->object_hash, uid);
 
 	if (!ico)
 		return NULL;
 
-	vcalobj = get_calendar_base_vobject (backend);
-	vobj = ical_object_to_vobject (ico);
-	addVObjectProp (vcalobj, vobj);
+	/* string_from_ical_object() uses writeMemVObject(), which uses
+	 * realloc(), so we must free its result with free() instead of
+	 * g_free().  We take a copy of the result so that callers can use the
+	 * normal glib function to free it.
+	 */
 
-	buf = writeMemVObject (NULL, NULL, vcalobj);
+	buf = string_from_ical_object (backend, ico);
+	retval = g_strdup (buf);
+	free (buf);
 
-	cleanVObject (vcalobj);
-	cleanStrTbl ();
+	return retval;
+}
 
-	return buf;
+struct build_event_list_closure {
+	CalBackend *backend;
+	GList *event_list;
+};
+
+/* Builds a sorted list of event object instances.  Used as a callback from
+ * ical_object_generate_events().
+ */
+static int
+build_event_list (iCalObject *ico, time_t start, time_t end, void *data)
+{
+	CalObjInstance *icoi;
+	struct build_event_list_closure *c;
+
+	c = data;
+
+	icoi = g_new (CalObjInstance, 1);
+	icoi->calobj = string_from_ical_object (c->backend, ico);
+	icoi->start = start;
+	icoi->end = end;
+
+	c->event_list = g_list_prepend (c->event_list, icoi);
+
+	return TRUE;
+}
+
+/* Compares two CalObjInstance structures by their start times.  Called from
+ * g_list_sort().
+ */
+static gint
+compare_instance_func (gconstpointer a, gconstpointer b)
+{
+	const CalObjInstance *ca, *cb;
+	time_t diff;
+
+	ca = a;
+	cb = b;
+
+	diff = ca->start - cb->start;
+	return (diff < 0) ? -1 : (diff > 0) ? 1 : 0;
+}
+
+/**
+ * cal_backend_get_events_in_range:
+ * @backend: A calendar backend.
+ * @start: Start time for query.
+ * @end: End time for query.
+ * 
+ * Builds a sorted list of calendar event object instances that occur or recur
+ * within the specified time range.  Each object instance contains the object
+ * itself and the start/end times at which it occurs or recurs.
+ * 
+ * Return value: A list of calendar event object instances, sorted by their
+ * start times.
+ **/
+GList *
+cal_backend_get_events_in_range (CalBackend *backend, time_t start, time_t end)
+{
+	CalBackendPrivate *priv;
+	struct build_event_list_closure c;
+	GList *l;
+
+	g_return_val_if_fail (backend != NULL, NULL);
+	g_return_val_if_fail (IS_CAL_BACKEND (backend), NULL);
+
+	priv = backend->priv;
+	g_return_val_if_fail (priv->loaded, NULL);
+
+	g_return_val_if_fail (start != -1 && end != -1, NULL);
+	g_return_val_if_fail (start <= end, NULL);
+
+	c.backend = backend;
+	c.event_list = NULL;
+
+	for (l = priv->events; l; l = l->next) {
+		iCalObject *ico;
+
+		ico = l->data;
+		ical_object_generate_events (ico, start, end, build_event_list, &c);
+	}
+
+	c.event_list = g_list_sort (c.event_list, compare_instance_func);
+	return c.event_list;
 }
diff --git a/calendar/pcs/cal-backend.h b/calendar/pcs/cal-backend.h
index e972cbd59e..aa54a3339d 100644
--- a/calendar/pcs/cal-backend.h
+++ b/calendar/pcs/cal-backend.h
@@ -27,6 +27,7 @@
 #include "evolution-calendar.h"
 #include "cal-common.h"
 #include "cal.h"
+#include "cal-util.h"
 
 BEGIN_GNOME_DECLS
 
@@ -39,9 +40,10 @@ BEGIN_GNOME_DECLS
 #define IS_CAL_BACKEND(obj)         (GTK_CHECK_TYPE ((obj), CAL_BACKEND_TYPE))
 #define IS_CAL_BACKEND_CLASS(klass) (GTK_CHECK_CLASS_TYPE ((klass), CAL_BACKEND_TYPE))
 
+/* Load status values */
 typedef enum {
-	CAL_BACKEND_LOAD_SUCCESS,		/* Loading OK */
-	CAL_BACKEND_LOAD_ERROR			/* We need better error reporting in libversit */
+	CAL_BACKEND_LOAD_SUCCESS,	/* Loading OK */
+	CAL_BACKEND_LOAD_ERROR		/* We need better error reporting in libversit */
 } CalBackendLoadStatus;
 
 struct _CalBackend {
@@ -68,6 +70,8 @@ CalBackendLoadStatus cal_backend_load (CalBackend *backend, GnomeVFSURI *uri);
 
 char *cal_backend_get_object (CalBackend *backend, const char *uid);
 
+GList *cal_backend_get_events_in_range (CalBackend *backend, time_t start, time_t end);
+
 
 
 END_GNOME_DECLS
diff --git a/calendar/pcs/cal.c b/calendar/pcs/cal.c
index 1ce1d91716..664d9ef416 100644
--- a/calendar/pcs/cal.c
+++ b/calendar/pcs/cal.c
@@ -196,6 +196,63 @@ Cal_get_object (PortableServer_Servant servant,
 	}
 }
 
+/* Cal::get_events_in_range method */
+static Evolution_Calendar_CalObjInstanceSeq *
+Cal_get_events_in_range (PortableServer_Servant servant,
+			 const Evolution_Calendar_Time_t start,
+			 const Evolution_Calendar_Time_t end,
+			 CORBA_Environment *ev)
+{
+	Cal *cal;
+	CalPrivate *priv;
+	time_t t_start, t_end;
+	Evolution_Calendar_CalObjInstanceSeq *seq;
+	GList *elist, *l;
+	int n, i;
+
+	cal = CAL (bonobo_object_from_servant (servant));
+	priv = cal->priv;
+
+	t_start = (time_t) start;
+	t_end = (time_t) end;
+
+	if (t_start > t_end || t_start == -1 || t_end == -1) {
+		CORBA_exception_set (ev, CORBA_USER_EXCEPTION,
+				     ex_Evolution_Calendar_Cal_InvalidRange,
+				     NULL);
+		return NULL;
+	}
+
+	/* Figure out the list and allocate the sequence */
+
+	elist = cal_backend_get_events_in_range (priv->backend, t_start, t_end);
+	n = g_list_length (elist);
+
+	seq = Evolution_Calendar_CalObjInstanceSeq__alloc ();
+	seq->_length = n;
+	seq->_buffer = CORBA_sequence_Evolution_Calendar_CalObjInstance_allocbuf (n);
+
+	/* Fill the sequence */
+
+	for (i = 0, l = elist; i < n; i++, l = l->next) {
+		CalObjInstance *icoi;
+		Evolution_Calendar_CalObjInstance *corba_icoi;
+
+		icoi = l->data;
+		corba_icoi = &seq->_buffer[i];
+
+		corba_icoi->calobj = CORBA_string_dup (icoi->calobj);
+		corba_icoi->start = icoi->start;
+		corba_icoi->end = icoi->end;
+	}
+
+	/* Done */
+
+	cal_obj_instance_list_free (elist);
+
+	return seq;
+}
+
 /**
  * cal_get_epv:
  * @void:
@@ -212,6 +269,7 @@ cal_get_epv (void)
 	epv = g_new0 (POA_Evolution_Calendar_Cal__epv, 1);
 	epv->_get_uri = Cal_get_uri;
 	epv->get_object = Cal_get_object;
+	epv->get_events_in_range = Cal_get_events_in_range;
 
 	return epv;
 }