private static void RemoveExpiredCachedRecords(Zone currentZone)
{
//remove expired entries in current zone
{
List <KeyValuePair <DnsResourceRecordType, DnsResourceRecord[]> > updateEntries = null;
foreach (KeyValuePair <DnsResourceRecordType, DnsResourceRecord[]> entry in currentZone._entries)
{
foreach (DnsResourceRecord record in entry.Value)
{
if (record.TtlValue < 1u)
{
//create new entry
if (updateEntries == null)
{
updateEntries = new List <KeyValuePair <DnsResourceRecordType, DnsResourceRecord[]> >();
}
List <DnsResourceRecord> newRecords = new List <DnsResourceRecord>(entry.Value.Length);
foreach (DnsResourceRecord existingRecord in entry.Value)
{
if (existingRecord.TtlValue < 1u)
{
continue;
}
newRecords.Add(existingRecord);
}
updateEntries.Add(new KeyValuePair <DnsResourceRecordType, DnsResourceRecord[]>(entry.Key, newRecords.ToArray()));
break;
}
}
}
if (updateEntries != null)
{
foreach (KeyValuePair <DnsResourceRecordType, DnsResourceRecord[]> updateEntry in updateEntries)
{
if (updateEntry.Value.Length > 0)
{
currentZone._entries.AddOrUpdate(updateEntry.Key, updateEntry.Value, delegate(DnsResourceRecordType key, DnsResourceRecord[] existingRecords)
{
return(updateEntry.Value);
});
}
else
{
currentZone._entries.TryRemove(updateEntry.Key, out DnsResourceRecord[] removedValues);
}
}
}
}
//remove expired entries in sub zones
{
List <string> subZonesToRemove = null;
foreach (KeyValuePair <string, Zone> zone in currentZone._zones)
{
RemoveExpiredCachedRecords(zone.Value);
if ((zone.Value._zones.Count == 0) && (zone.Value._entries.Count == 0))
{
if (subZonesToRemove == null)
{
subZonesToRemove = new List <string>();
}
subZonesToRemove.Add(zone.Key);
}
}
if (subZonesToRemove != null)
{
foreach (string subZone in subZonesToRemove)
{
currentZone._zones.TryRemove(subZone, out Zone value);
}
}
}
}
