public static IDataReader AddToCache(ISqlQuery query, IDataReader data)
{
ICacheKey key = new CacheKey(query);
CachedDataReader cached = new CachedDataReader(data);
int newSize = cached.Size() + key.Query.Length;
ICacheItem item;
if (newSize < CacheObjectSizeLimit)
{
while (CacheSize + newSize > CacheSizeLimit && QueryOrder.Count > 0)
{
ICacheKey oldestKey = QueryOrder.Peek();
if (!RemoveFromCache(oldestKey))
{
break;
}
}
if (QueryOrder.Count == 0 && CacheSize != 0)
{
CacheSize = 0;
QueryResultCache.Clear();
// this should be logged but thrwing an error seems too much... test the hellout of this?
}
// It is possible that we failed to remove it from the cache, so just bail out
// if still won't fit
if (CacheSize + newSize <= CacheSizeLimit)
{
item = new CacheItem(cached, newSize);
if (QueryResultCache.TryAdd(key, item))
{
QueryOrder.Enqueue(key);
}
}
else
{
}
}
// whether or not we end up caching the datareader, we must return the in-memory copy because you can't go back
// after reading a datareader. We only try to cache when buffering is enabled, so nothing's really lost.
return cached;
}
public static bool TryGetCachedData(ISqlQuery query, out IDataReader data)
{
var key = new CacheKey(query);
ICacheItem cached;
if (QueryResultCache.TryGetValue(key, out cached)) {
if (cached.Expired)
{
RemoveFromCache(key);
data = null;
return false;
}
else
{
CachedDataReader reader = ((CacheItem)cached).Data;
reader.Reset();
data = new CachedDataReaderView(reader);
return true;
}
} else {
data=null;
return false;
}
}
public static bool RemoveFromCache(ISqlQuery query)
{
ICacheKey key = new CacheKey(query);
return RemoveFromCache(key);
}
