public IEnumerator <KeyValuePair <TKey, TValue> > GetEnumerator()
{
return(EntriesAsCollection
.Where(e => !e.Value.Expired)
.Select(e => new KeyValuePair <TKey, TValue>(e.Key, e.Value.Data))
.GetEnumerator());
}
public bool Remove(KeyValuePair <TKey, TValue> item)
{
EntryData entryData;
return(_Entries.TryGetValue(item.Key, out entryData) &&
(Object.Equals(entryData.Data, item.Value)) &&
EntriesAsCollection.Remove(new KeyValuePair <TKey, EntryData>(item.Key, entryData)));
}
private void Clean()
{
KeyValuePair <TKey, EntryData> queued;
bool expiredEntries = _LastWrite.TryPeek(out queued) && queued.Value.Expired;
while (expiredEntries || (_Entries.Count > MaxEntries))
{
// TODO: Ideally we'd have a queue where we could peek first, check if it's something we want,
// then dequeue iff what's @ the head == what we peeked. But this is good enough - at worst
// we'll have a slightly over-aggressive clean
if (!_LastWrite.TryDequeue(out queued))
{
break;
}
expiredEntries = queued.Value.Expired;
EntriesAsCollection.Remove(queued);
}
}
/**
* Gets the existing value if the key was present, or adds a new value if the key was not present.
*
* If the value was added, returns true and sets currentValue = newValue.
*
* If the value already existed, returns false and returns the existing value in currentValue.
**/
public bool GetOrAdd(TKey key, TValue newValue, out TValue currentValue)
{
var newEntry = GetEntry(newValue);
var existingEntry = _Entries.GetOrAdd(key, newEntry);
if (existingEntry != newEntry)
{
while ((!existingEntry.GetData(out currentValue)) && (existingEntry != newEntry))
{
EntriesAsCollection.Remove(new KeyValuePair <TKey, EntryData>(key, existingEntry));
existingEntry = _Entries.GetOrAdd(key, newEntry);
}
if (existingEntry != newEntry)
{
return(false);
}
}
TrackWrite(newEntry, key);
currentValue = newValue;
return(true);
}
