[evolution-data-server/gnome-3-18] Bug 746675 - Workaround thread unsafety of icaltimezone_load_builtin_timezone()

[Milan Crha <mcrha src gnome org>]

commit 41a388df9b9a69ffff7eecb0e846c7a6e2a44210
Author: Milan Crha <mcrha redhat com>
Date:   Wed Nov 25 09:02:32 2015 +0100

    Bug 746675 - Workaround thread unsafety of icaltimezone_load_builtin_timezone()

 calendar/libedata-cal/e-subprocess-cal-factory.c |   30 ++++++++++++++++++++++
 1 files changed, 30 insertions(+), 0 deletions(-)
---
diff --git a/calendar/libedata-cal/e-subprocess-cal-factory.c 
b/calendar/libedata-cal/e-subprocess-cal-factory.c
index c268684..0537a46 100644
--- a/calendar/libedata-cal/e-subprocess-cal-factory.c
+++ b/calendar/libedata-cal/e-subprocess-cal-factory.c
@@ -137,6 +137,36 @@ ESubprocessCalFactory *
 e_subprocess_cal_factory_new (GCancellable *cancellable,
                               GError **error)
 {
+       icalarray *builtin_timezones;
+       gint ii;
+
+#ifdef HAVE_ICAL_UNKNOWN_TOKEN_HANDLING
+       ical_set_unknown_token_handling_setting (ICAL_DISCARD_TOKEN);
+#endif
+
+       /* XXX Pre-load all built-in timezones in libical.
+        *
+        *     Built-in time zones in libical 0.43 are loaded on demand,
+        *     but not in a thread-safe manner, resulting in a race when
+        *     multiple threads call icaltimezone_load_builtin_timezone()
+        *     on the same time zone.  Until built-in time zone loading
+        *     in libical is made thread-safe, work around the issue by
+        *     loading all built-in time zones now, so libical's internal
+        *     time zone array will be fully populated before any threads
+        *     are spawned.
+        */
+       builtin_timezones = icaltimezone_get_builtin_timezones ();
+       for (ii = 0; ii < builtin_timezones->num_elements; ii++) {
+               icaltimezone *zone;
+
+               zone = icalarray_element_at (builtin_timezones, ii);
+
+               /* We don't care about the component right now,
+                * we just need some function that will trigger
+                * icaltimezone_load_builtin_timezone(). */
+               icaltimezone_get_component (zone);
+       }
+
        return g_initable_new (
                E_TYPE_SUBPROCESS_CAL_FACTORY,
                cancellable, error, NULL);