Use more g_signal_connect_object()

Most of these are probably paranoid, not bugs. I haven't done an
exhaustive review to see what really needs it: that would be
time-consuming and require significant familiarity with the Calendar
codebase. This was just a quick check. Anyway, I vote for paranoid
when it comes to using g_signal_connect() regardless. It's dangerous,
and there's no reason to ever leave a signal connected after the user
data object has been destroyed.

Fixes #423

src/views/gcal-month-popover.c

@@ -354,10 +354,11 @@ update_event_list (GcalMonthPopover *self)
 
       gtk_container_add (GTK_CONTAINER (self->listbox), event_widget);
 
-      g_signal_connect (event_widget,
-                        "activate",
-                        G_CALLBACK (event_activated_cb),
-                        self);
+      g_signal_connect_object (event_widget,
+                               "activate",
+                               G_CALLBACK (event_activated_cb),
+                               self,
+                               0);
     }
 
   gtk_widget_show_all (self->listbox);

src/views/gcal-month-view.c

@@ -188,8 +188,8 @@ setup_child_widget (GcalMonthView *self,
   if (!gtk_widget_get_parent (widget))
     gtk_widget_set_parent (widget, GTK_WIDGET (self));
 
-  g_signal_connect (widget, "activate", G_CALLBACK (on_event_activated_cb), self);
-  g_signal_connect (widget, "notify::visible", G_CALLBACK (on_event_widget_visibility_changed_cb), self);
+  g_signal_connect_object (widget, "activate", G_CALLBACK (on_event_activated_cb), self, 0);
+  g_signal_connect_object (widget, "notify::visible", G_CALLBACK (on_event_widget_visibility_changed_cb), self, 0);
 }
 
 static gboolean
@@ -861,7 +861,7 @@ setup_month_grid (GcalMonthView *self,
 
           cell = gcal_month_cell_new ();
 
-          g_signal_connect (cell, "show-overflow", G_CALLBACK (on_month_cell_show_overflow_popover_cb), self);
+          g_signal_connect_object (cell, "show-overflow", G_CALLBACK (on_month_cell_show_overflow_popover_cb), self, 0);
 
           self->month_cell[row][col] = cell;
 
@@ -2343,6 +2343,6 @@ gcal_month_view_init (GcalMonthView *self)
                           "context",
                           G_BINDING_DEFAULT);
 
-  g_signal_connect (self->overflow_popover, "event-activated", G_CALLBACK (on_month_popover_event_activated_cb), self);
+  g_signal_connect_object (self->overflow_popover, "event-activated", G_CALLBACK (on_month_popover_event_activated_cb), self, 0);
 }
 

src/views/gcal-week-header.c

@@ -221,7 +221,7 @@ setup_event_widget (GcalWeekHeader *self,
                     GtkWidget      *widget)
 {
   gtk_widget_set_margin_end (widget, 6);
-  g_signal_connect (widget, "activate", G_CALLBACK (on_event_widget_activated), self);
+  g_signal_connect_object (widget, "activate", G_CALLBACK (on_event_widget_activated), self, 0);
 }
 
 static inline void

src/views/gcal-week-view.c

@@ -118,10 +118,11 @@ update_grid_scroll_position (GcalWeekView *self)
 
       stack = gtk_widget_get_ancestor (GTK_WIDGET (self), GTK_TYPE_STACK);
 
-      g_signal_connect (stack,
-                        "notify::visible-child",
-                        G_CALLBACK (stack_visible_child_changed_cb),
-                        self);
+      g_signal_connect_object (stack,
+                               "notify::visible-child",
+                               G_CALLBACK (stack_visible_child_changed_cb),
+                               self,
+                               0);
 
       self->scroll_grid_timeout_id = 0;
 

src/views/gcal-year-view.c

@@ -492,7 +492,7 @@ update_sidebar (GcalYearView *year_view)
         {
           child_widget = l->data;
           gtk_widget_show (child_widget);
-          g_signal_connect (child_widget, "activate", G_CALLBACK (event_activated), year_view);
+          g_signal_connect_object (child_widget, "activate", G_CALLBACK (event_activated), year_view, 0);
           g_object_set_data (G_OBJECT (child_widget), "shift", GINT_TO_POINTER (i));
           gtk_container_add (GTK_CONTAINER (year_view->events_sidebar), child_widget);
         }
@@ -2118,7 +2118,7 @@ gcal_year_view_init (GcalYearView *self)
   /* bind GNOME Shell' show week numbers property to GNOME Calendar's one */
   self->calendar_settings = g_settings_new ("org.gnome.desktop.calendar");
   g_settings_bind (self->calendar_settings, "show-weekdate", self, "show-week-numbers", G_SETTINGS_BIND_DEFAULT);
-  g_signal_connect_swapped (self->calendar_settings, "changed::show-weekdate", G_CALLBACK (gtk_widget_queue_draw), self);
+  g_signal_connect_object (self->calendar_settings, "changed::show-weekdate", G_CALLBACK (gtk_widget_queue_draw), self, G_CONNECT_SWAPPED);
 
   /* layout */
   self->number_of_columns = 4;