[libgweather] timezone: Add a method to get a timezone by ID

[Jasper St. Pierre <jstpierre src gnome org>]

commit 6445973c7e8020717651c189913b07f4e3972bd5
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Tue Oct 22 16:59:57 2013 -0400

    timezone: Add a method to get a timezone by ID

 libgweather/gweather-timezone.c |   37 +++++++++++++++++++++++++++++++++----
 libgweather/gweather-timezone.h |    1 +
 2 files changed, 34 insertions(+), 4 deletions(-)
---
diff --git a/libgweather/gweather-timezone.c b/libgweather/gweather-timezone.c
index cb09009..c6c8b33 100644
--- a/libgweather/gweather-timezone.c
+++ b/libgweather/gweather-timezone.c
@@ -35,10 +35,9 @@
  *
  * A timezone.
  *
- * There are no public methods for creating timezones; they can only
- * be created by calling gweather_location_new_world() to parse
- * Locations.xml, and then calling various #GWeatherLocation methods
- * to extract relevant timezones from the location hierarchy.
+ * Timezones are global to the #GWeatherWorld; they can be gotten
+ * by passing gweather_timezone_get_by_tzid() with a tzid like
+ * "America/New_York" or "Europe/London".
  */
 
 struct _GWeatherTimezone {
@@ -150,6 +149,29 @@ parse_tzdata (const char *tzname, time_t start, time_t end,
     return TRUE;
 }
 
+static GHashTable *timezones = NULL;
+
+/**
+ * gweather_timezone_get_by_tzid:
+ * @tzid: A timezone identifier, like "America/New_York" or "Europe/London"
+ *
+ * Get the #GWeatherTimezone for @tzid.
+ *
+ * Returns: (transfer none): A #GWeatherTimezone. This object
+ * belongs to GWeather, do not unref it.
+ */
+GWeatherTimezone *
+gweather_timezone_get_by_tzid (const char *tzid)
+{
+    /* ensure that the database has been loaded and parsed */
+    gweather_location_get_world ();
+
+    if (timezones == NULL)
+       return NULL;
+
+    return g_hash_table_lookup (timezones, tzid);
+}
+
 static GWeatherTimezone *
 parse_timezone (GWeatherParser *parser)
 {
@@ -197,6 +219,13 @@ parse_timezone (GWeatherParser *parser)
        zone->has_dst = has_dst;
        zone->dst_offset = dst_offset;
 
+       if (timezones == NULL)
+           timezones = g_hash_table_new_full (g_str_hash, g_str_equal,
+                                              NULL, /* key owned by zone */
+                                              (GDestroyNotify) gweather_timezone_unref);
+
+       g_hash_table_insert (timezones, zone->id, zone);
+
        name = NULL;
     }
 
diff --git a/libgweather/gweather-timezone.h b/libgweather/gweather-timezone.h
index 220223a..42f9c4b 100644
--- a/libgweather/gweather-timezone.h
+++ b/libgweather/gweather-timezone.h
@@ -44,6 +44,7 @@ GWeatherTimezone *gweather_timezone_ref            (GWeatherTimezone *zone);
 void              gweather_timezone_unref          (GWeatherTimezone *zone);
 
 GWeatherTimezone *gweather_timezone_get_utc        (void);
+GWeatherTimezone *gweather_timezone_get_by_tzid    (const char *tzid);
 
 G_END_DECLS