From 692a9639a319ac05abcebd2d6fb224cd932bfaba Mon Sep 17 00:00:00 2001
From: Georges Basile Stavracas Neto <georges.stavracas@gmail.com>
Date: Wed, 18 May 2016 11:20:00 -0300
Subject: [PATCH] month-view: fix various reference issues with GDateTime

The current code does multiple needless unrefs, uses the
GDateTime API in a wrongly manner and leaks references
all around.

This causes the Calendar application to emit multiple warning
messages and in the worst case, crash immediately.

Fix that by rewriting the critical sections of the code that
deals with the start and end mark cells.

https://bugzilla.gnome.org/show_bug.cgi?id=763641
---
 src/gcal-month-view.c | 52 +++++++++++++++++++++++++++++++++----------
 1 file changed, 40 insertions(+), 12 deletions(-)

diff --git a/src/gcal-month-view.c b/src/gcal-month-view.c
index 96c52d3d..7dde81e4 100644
--- a/src/gcal-month-view.c
+++ b/src/gcal-month-view.c
@@ -261,12 +261,13 @@ show_popover_for_position (GcalMonthView *view,
   if (priv->start_mark_cell == NULL)
     return FALSE;
 
-  if (priv->pressed_overflow_indicator != -1 && !g_date_time_equal (priv->start_mark_cell, priv->end_mark_cell) &&
+  if (priv->pressed_overflow_indicator != -1 &&
+      g_date_time_equal (start_dt, end_dt) &&
       g_hash_table_contains (ppriv->overflow_cells, GINT_TO_POINTER (priv->pressed_overflow_indicator)))
     {
       priv->hovered_overflow_indicator = priv->pressed_overflow_indicator;
 
-      rebuild_popover_for_day (GCAL_MONTH_VIEW (widget), g_date_time_get_day_of_month (priv->end_mark_cell));
+      rebuild_popover_for_day (GCAL_MONTH_VIEW (widget), g_date_time_get_day_of_month (end_dt));
       gtk_widget_show_all (priv->overflow_popover);
 
       gtk_widget_queue_draw (widget);
@@ -287,7 +288,7 @@ show_popover_for_position (GcalMonthView *view,
         }
 
       /* Only setup an end date when days are different */
-      if (g_date_time_compare (priv->start_mark_cell, priv->end_mark_cell))
+      if (!g_date_time_compare (start_dt, end_dt))
         {
           GDateTime *tmp_dt;
 
@@ -301,9 +302,6 @@ show_popover_for_position (GcalMonthView *view,
         }
 
       g_signal_emit_by_name (GCAL_VIEW (widget), "create-event", start_dt, end_dt, x, y);
-
-      g_clear_pointer (&start_dt, g_date_time_unref);
-      g_clear_pointer (&end_dt, g_date_time_unref);
     }
 
   gtk_widget_queue_draw (widget);
@@ -1870,10 +1868,13 @@ gcal_month_view_button_press (GtkWidget      *widget,
 
   if (clicked_cell >= priv->days_delay && clicked_cell < days)
     {
+      g_clear_pointer (&priv->start_mark_cell, g_date_time_unref);
+
       priv->keyboard_cell = clicked_cell;
       priv->start_mark_cell = g_date_time_new_local (priv->date->year, priv->date->month,
-                                                    priv->keyboard_cell - priv->days_delay + 1,
-                                                    0, 0, 0);
+                                                     priv->keyboard_cell - priv->days_delay + 1,
+                                                     0, 0, 0);
+      gtk_widget_queue_draw (widget);
     }
 
   if (pressed_indicator && g_hash_table_contains (ppriv->overflow_cells, GINT_TO_POINTER (clicked_cell)))
@@ -1916,14 +1917,39 @@ gcal_month_view_motion_notify_event (GtkWidget      *widget,
 
       if (new_end_cell >= priv->days_delay && new_end_cell < days)
         {
+          guint previous_end_cell;
+
+          previous_end_cell = new_end_cell;
+
+          /* Let the keyboard focus track the pointer */
           priv->keyboard_cell = new_end_cell;
 
-          if (g_date_time_compare (priv->start_mark_cell, priv->end_mark_cell))
-            priv->hovered_overflow_indicator = -1;
-          if (g_date_time_get_day_of_month (priv->end_mark_cell) + priv->days_delay - 1 != new_end_cell)
+          /*
+           * When there is a previously set end mark, it should be
+           * cleared before assigning a new one.
+           */
+          if (priv->end_mark_cell)
+            {
+              previous_end_cell = g_date_time_get_day_of_month (priv->end_mark_cell) - 1;
+
+              g_clear_pointer (&priv->end_mark_cell, g_date_time_unref);
+            }
+
+          if (priv->start_mark_cell &&
+              priv->end_mark_cell &&
+              !g_date_time_equal (priv->start_mark_cell, priv->end_mark_cell))
+            {
+              priv->hovered_overflow_indicator = -1;
+            }
+
+          if (previous_end_cell != new_end_cell)
             gtk_widget_queue_draw (widget);
 
-          priv->end_mark_cell = g_date_time_new_local (priv->date->year, priv->date->month, new_end_cell - priv->days_delay + 1, 0, 0, 0);
+          priv->end_mark_cell = g_date_time_new_local (priv->date->year,
+                                                       priv->date->month,
+                                                       new_end_cell - priv->days_delay + 1,
+                                                       0, 0, 0);
+
           return TRUE;
         }
     }
@@ -1965,6 +1991,8 @@ gcal_month_view_button_release (GtkWidget      *widget,
 
   if (current_day >= priv->days_delay && current_day < days)
     {
+      g_clear_pointer (&priv->end_mark_cell, g_date_time_unref);
+
       priv->keyboard_cell = current_day;
       priv->end_mark_cell = g_date_time_new_local (priv->date->year, priv->date->month, current_day - priv->days_delay + 1, 0, 0, 0);
       return show_popover_for_position (GCAL_MONTH_VIEW (widget), x, y, released_indicator);