[california] Handle libical's tzid prefix

[Jim Nelson <jnelson src gnome org>]

commit 822c1d0c668b79643e44395014201dacc4a001fb
Author: Jim Nelson <jim yorba org>
Date:   Tue Mar 25 16:08:06 2014 -0700

    Handle libical's tzid prefix
    
    Some users of libical generate iCal components with its tzid prefix.
    This catches those situations and converts the prefixed tzid into
    a proper Olson zone.

 src/component/component-date-time.vala |   12 ++++++++++--
 vapi/libical.vapi                      |    2 +-
 2 files changed, 11 insertions(+), 3 deletions(-)
---
diff --git a/src/component/component-date-time.vala b/src/component/component-date-time.vala
index 56fcb63..3795a69 100644
--- a/src/component/component-date-time.vala
+++ b/src/component/component-date-time.vala
@@ -100,8 +100,16 @@ public class DateTime : BaseObject, Gee.Hashable<DateTime>, Gee.Comparable<DateT
             throw new ComponentError.INVALID("DATE-TIME for %s is invalid", ical_prop_kind.to_string());
         
         unowned iCal.icalparameter? param = prop.get_first_parameter(iCal.icalparameter_kind.TZID_PARAMETER);
-        if (param != null)
-            zone = new Calendar.OlsonZone(param.get_tzid());
+        if (param != null) {
+            // first, see if libical can convert this into builtin timezone; this indicates the
+            // component was (probably) created with another instance of libical that has added its
+            // timezone "prefix" to the tzid; otherwise, treat tzid as a straight-up Olson zone
+            unowned iCal.icaltimezone? tz = 
iCal.icaltimezone.get_builtin_timezone_from_tzid(param.get_tzid());
+            if (tz != null)
+                zone = new Calendar.OlsonZone(tz.get_location());
+            else
+                zone = new Calendar.OlsonZone(param.get_tzid());
+        }
         
         kind = ical_prop_kind;
     }
diff --git a/vapi/libical.vapi b/vapi/libical.vapi
index fb5e7df..7950841 100644
--- a/vapi/libical.vapi
+++ b/vapi/libical.vapi
@@ -1402,7 +1402,7 @@ namespace iCal {
                [CCode (cname = "icaltimezone_get_builtin_timezone_from_offset")]
                public static unowned iCal.icaltimezone get_builtin_timezone_from_offset (int offset, string 
tzname);
                [CCode (cname = "icaltimezone_get_builtin_timezone_from_tzid")]
-               public static unowned iCal.icaltimezone get_builtin_timezone_from_tzid (string tzid);
+               public static unowned iCal.icaltimezone? get_builtin_timezone_from_tzid (string tzid);
                [CCode (cname = "icaltimezone_get_builtin_timezones")]
                public static unowned iCal.icalarray get_builtin_timezones ();
                [CCode (cname = "icaltimezone_get_component")]