//
// TryGetTimeZone -
//
// Helper function for retrieving a TimeZoneInfo object by <time_zone_name>.
//
// This function may return null.
//
// assumes cachedData lock is taken
//
private static TimeZoneInfoResult TryGetTimeZone(ref TimeZoneInformation timeZoneInformation, bool dstDisabled, out TimeZoneInfo value, out Exception e, CachedData cachedData)
{
TimeZoneInfoResult result = TimeZoneInfoResult.Success;
e = null;
TimeZoneInfo match = null;
// check the cache
if (cachedData._systemTimeZones != null)
{
if (cachedData._systemTimeZones.TryGetValue(timeZoneInformation.TimeZoneKeyName, out match))
{
if (dstDisabled && match._supportsDaylightSavingTime)
{
// we found a cache hit but we want a time zone without DST and this one has DST data
value = CreateCustomTimeZone(match._id, match._baseUtcOffset, match._displayName, match._standardDisplayName);
}
else
{
value = new TimeZoneInfo(match._id, match._baseUtcOffset, match._displayName, match._standardDisplayName,
match._daylightDisplayName, match._adjustmentRules, false);
}
return(result);
}
}
// fall back to reading from the local machine
// when the cache is not fully populated
result = TryGetFullTimeZoneInformation(timeZoneInformation, out match, out e, timeZoneInformation.Dtzi.Bias);
if (result == TimeZoneInfoResult.Success)
{
if (cachedData._systemTimeZones == null)
{
cachedData._systemTimeZones = new Dictionary <string, TimeZoneInfo>();
}
cachedData._systemTimeZones.Add(timeZoneInformation.TimeZoneKeyName, match);
if (dstDisabled && match._supportsDaylightSavingTime)
{
// we found a cache hit but we want a time zone without DST and this one has DST data
value = CreateCustomTimeZone(match._id, match._baseUtcOffset, match._displayName, match._standardDisplayName);
}
else
{
value = new TimeZoneInfo(match._id, match._baseUtcOffset, match._displayName, match._standardDisplayName,
match._daylightDisplayName, match._adjustmentRules, false);
}
}
else
{
value = null;
}
return(result);
}
private static void PopulateAllSystemTimeZones(CachedData cachedData)
{
Debug.Assert(Monitor.IsEntered(cachedData));
uint index = 0;
TIME_DYNAMIC_ZONE_INFORMATION tdzi;
while (Interop.mincore.EnumDynamicTimeZoneInformation(index, out tdzi) != Interop.Errors.ERROR_NO_MORE_ITEMS)
{
TimeZoneInformation timeZoneInformation = new TimeZoneInformation(tdzi);
TimeZoneInfo value;
Exception e;
TimeZoneInfoResult result = TryGetTimeZone(ref timeZoneInformation, false, out value, out e, cachedData);
index++;
}
}