timeline: Process events in batches

A batch size of 5 doesn't seem to impact the mainloop
any more than a batch of size 1, but it reduces the
amount of time spinning the loop quite considerably.

src/core/gcal-timeline.c

@@ -32,6 +32,8 @@
 
 #include <libedataserver/libedataserver.h>
 
+#define BATCH_SIZE 5
+
 typedef enum
 {
   ADD_EVENT,
@@ -581,15 +583,21 @@ timeline_source_dispatch (GSource     *source,
 {
   TimelineSource *timeline_source;
   GcalTimeline *self;
+  gint processed_events;
+
+  GCAL_ENTRY;
+
+  processed_events = 0;
+  timeline_source = (TimelineSource*) source;
+  self = timeline_source->timeline;
+
+  while (processed_events < BATCH_SIZE && !g_queue_is_empty (self->event_queue))
+    {
       GcalRange *event_range;
       QueueData *queue_data;
       GcalEvent *event;
       gint i;
 
-  GCAL_ENTRY;
-
-  timeline_source = (TimelineSource*) source;
-  self = timeline_source->timeline;
       queue_data = g_queue_pop_head (self->event_queue);
 
       event = queue_data->event;
@@ -663,6 +671,9 @@ timeline_source_dispatch (GSource     *source,
 
       queue_data_free (queue_data);
 
+      processed_events++;
+    }
+
   GCAL_RETURN (G_SOURCE_CONTINUE);
 }