public void Add(string key, object value, TimeSpan slidingExpiration, CacheItemRemovedCallback cacheRemove)
{
string cacheKey = CacheKey(key, _hashkey);
lock (GetLock(cacheKey, TimeSpan.Zero, slidingExpiration, null, this))
{
object local = NCache.Get(cacheKey);
if (local == null)
local = NHashtable.InternalCallback(cacheKey);
}
}
public object Get(string key)
{
string cacheKey = NHashtable.CacheKey(key, _hashkey);
object obj = base[cacheKey];
CacheEntry entry = null;
if (CacheLockbox.TryGetCacheEntry(cacheKey, out entry))
{
lock (CacheLockbox.GetLock(cacheKey))
{
object local = NCache.Get(cacheKey);
if (local == null)
local = NHashtable.InternalCallback(cacheKey);
return local;
}
}
return obj;
}
/// <summary>
/// Callback function used to re-insert a expired cached object into the cache
/// </summary>
/// <param name="key">The key used to put the object on the cache</param>
internal static object InternalCallback(string cacheKey)
{
CacheEntry cacheEntry = null;
if (!CacheLockbox.TryGetCacheEntry(cacheKey, out cacheEntry))
return null;
object obj = null;
NHashtable nHash = ((HashCacheEntry)cacheEntry).RefTable;
if (nHash != null) {
obj = nHash[cacheKey];
if(obj != null)
NCache.Insert(cacheKey, obj, null, (int)cacheEntry.SlidingExpiration.TotalSeconds, CacheItemPriority.Normal, new CacheItemRemovedCallback(NHashtable.ItemRemovedCallback));
}
// signal the CacheLockbox about the usage of the object
CacheLockbox.UpdateCacheEntry(cacheKey, DateTime.Now);
return obj;
}
/// <summary>
/// Callback method called when a object is removed for the ASP.NET cache.
/// </summary>
/// <param name="key"></param>
/// <param name="value"></param>
/// <param name="reason">The reason an item was removed from the ASP.NET cache</param>
internal static void ItemRemovedCallback(string cacheKey, object value, CacheItemRemovedReason reason)
{
if (reason == CacheItemRemovedReason.Expired)
{
int num = cacheKey.IndexOf('-');
string key = cacheKey.Substring(0, num);
CacheEntry cacheEntry = null;
if (CacheLockbox.TryGetCacheEntry(cacheKey, out cacheEntry))
{
if (cacheEntry.LastUse.Add(cacheEntry.SlidingExpiration) > DateTime.Now) {
NCache.cache_.Insert(cacheKey, value, null, DateTime.Now.Add(TimeSpan.FromSeconds(30.0)), TimeSpan.Zero, CacheItemPriority.Low, null);
ThreadPool.QueueUserWorkItem(delegate(object o)
{
string k = o.ToString();
lock (CacheLockbox.GetInternalLock(k)) {
InternalCallback(k);
}
}, cacheKey);
}
else {
lock (CacheLockbox.GetLock(cacheKey))
{
HashCacheEntry hashEntry = (HashCacheEntry)cacheEntry;
if (hashEntry.CacheRemoved != null)
hashEntry.CacheRemoved(key, value, reason);
NHashtable table = hashEntry.RefTable;
if (table != null)
table.Remove(cacheKey);
}
CacheLockbox.Remove(cacheKey);
}
}
}
}
internal static object GetLock(string key, TimeSpan refreshInterval, TimeSpan slidingExpiration, CacheItemRemovedCallback cacehRemoved, NHashtable table)
{
HashCacheEntry entry = new HashCacheEntry();
entry.RefreshInterval = refreshInterval;
entry.SlidingExpiration = slidingExpiration;
entry.LastUse = DateTime.Now;
entry.CacheRemoved = cacehRemoved;
entry.RefTable = table;
CacheLockbox.Add(key, entry);
return entry.Locker;
}