/// <summary>
/// Add or update an entry to the LRUCache and put it in the front of the lru list.
/// </summary>
/// <param name="key"></param>
/// <param name="value"></param>
/// <param name="replace">whether to replace the value if already exist </param>
/// <param name="charge">charge for capacity</param>
/// <returns></returns>
private bool Add(TKey key, ref TValue value, bool replace = true, ulong charge = 0)
{
bool evicted = false;
bool itemLargerThanCapacity = false;
if (key == null)
{
throw new ArgumentNullException("key");
}
using (_lock.GetWriterLock())
{
LinkedListNode <Entry <TKey, TValue> > node;
// Check for existing item
if (_map.TryGetValue(key, out node))
{
_lruList.MoveToFront(node);
if (replace)
{
node.Value.Value = value;
}
else
{
value = node.Value.Value;
}
return(false);
}
if (_capacity == 0 || charge <= _capacity)
{
// Add new item
var entry = new Entry <TKey, TValue> {
Key = key, Value = value, Charge = charge, CreationTime = DateTimeOffset.Now
};
_lruList.AddFirst(entry);
_map[key] = _lruList.First;
_usage += charge;
}
else
{
itemLargerThanCapacity = true;
}
// Verify size not exceeded
while ((_maxEntries != 0 && _lruList.Count > _maxEntries) || (_capacity != 0 && _usage > _capacity))
{
evicted = true;
RemoveOldest();
}
}
if (itemLargerThanCapacity)
{
ItemOverCapacity?.Invoke(new KeyValuePair <TKey, TValue>(key, value));
}
return(evicted);
}
public DiskCache(string cacheRootPath, int maxEntryCount, IFileSystem fs = null)
{
_cacheRootPath = cacheRootPath;
_cacheTmpPath = Path.Combine(_cacheRootPath, "tmp");
_fs = fs;
if (_fs == null)
{
_fs = new FileSystem();
}
_fs.DirectoryCreate(_cacheRootPath);
_fs.DirectoryReCreate(_cacheTmpPath);
_lruCache = new LRUCache <string, DiskCacheEntry>(maxEntryCount);
_lruCache.ItemEvicted += (KeyValuePair <string, DiskCacheEntry> pair) => FinishErase(pair.Key, pair.Value);
_lruCache.ItemOverCapacity += (kv) => ItemOverCapacity?.Invoke(kv.Key);
}
public KeyPrefixCacheDecorator(string prefix, ICache cache)
{
_prefix = prefix;
_decorated = cache;
_decorated.ItemOverCapacity += (key) => ItemOverCapacity?.Invoke(key);
}
private void TriggerItemCapacity(KeyValuePair <string, ArraySegment <byte> > kv)
{
ItemOverCapacity?.Invoke(kv.Key);
}
