/// <summary>
/// Implemented in derived classes to add a new entry to the cache
/// </summary>
/// <param name="key">The key for the new entry</param>
/// <param name="data">The data for the new entry</param>
/// <param name="cachePriority">The entry priority</param>
/// <returns>The newly created cache entry</returns>
protected override AbstractCacheEntry AddEntry(string key, byte[] data, CachePriority cachePriority)
{
var entry = new MemoryCacheEntry(key, data, cachePriority);
_cache.AddOrUpdate(key, entry, (k, e) => entry);
return(entry);
}
public int Compare(MemoryCacheEntry entry1, MemoryCacheEntry entry2)
{
var ret = DateTime.Compare (entry1.UtcLastUpdateUsage , entry2.UtcLastUpdateUsage);
if (ret == 0)
return entry1.UsageEntryRef.DateTimeIndex - entry2.UsageEntryRef.DateTimeIndex;
return ret;
}
public int Compare(MemoryCacheEntry entry1, MemoryCacheEntry entry2)
{
var ret = DateTime.Compare(entry1.UtcLastUpdateUsage, entry2.UtcLastUpdateUsage);
if (ret == 0)
{
return(entry1.UsageEntryRef.DateTimeIndex - entry2.UsageEntryRef.DateTimeIndex);
}
return(ret);
}
/// <summary>
/// Clears the ClockCache of all entries.
/// </summary>
public void Clear()
{
m_readerWriterLock.EnterWriteLock();
try
{
m_currentSize = 0;
m_beforeClockHand = null;
m_dictionary.Clear();
}
finally
{
m_readerWriterLock.ExitWriteLock();
}
}
public new void Add (MemoryCacheEntry entry)
{
var now = DateTime.UtcNow;
if (now == prevDateTime)
dateTimeIndex++;
else
dateTimeIndex = 0;
prevDateTime = now;
entry.UtcLastUpdateUsage = now;
entry.UsageEntryRef = new UsageEntryRef ();
entry.UsageEntryRef.DateTimeIndex = dateTimeIndex;
base.Add (entry);
}
public void Add(MemoryCacheEntry entry)
{
var now = DateTime.UtcNow;
if (now == prevDateTime)
{
dateTimeIndex++;
}
else
{
dateTimeIndex = 0;
}
prevDateTime = now;
entry.UtcLastUpdateUsage = now;
entry.UsageEntryRef = new UsageEntryRef();
entry.UsageEntryRef.DateTimeIndex = dateTimeIndex;
base.Add(entry);
}
/// <summary>
/// Removes a specific key from the cache.
/// </summary>
/// <param name="key">Key to remove</param>
/// <returns>True if the key was removed from the cache</returns>
public bool Remove(TKey key)
{
while (!m_readerWriterLock.TryEnterReadLock(0))
{
}
try
{
MemoryCacheEntry <TKey, TValue> entry;
if (!m_dictionary.TryGetValue(key, out entry))
{
return(false);
}
// Unlink the entry.
entry.Previous.Next = entry.Next;
entry.Next.Previous = entry.Previous;
m_dictionary.Remove(entry.Key);
m_currentSize--;
if (ReferenceEquals(entry, m_beforeClockHand))
{
// We removed what beforeClockHand pointed to,
// so advance it to an extant entry.
m_beforeClockHand = m_beforeClockHand.Next;
if (m_currentSize == 0)
{
// Cache is now empty.
m_beforeClockHand = null;
}
}
return(true);
}
finally
{
m_readerWriterLock.ExitReadLock();
}
}
/// <summary>
/// Adds the specified key and value to the dictionary.
/// </summary>
/// <param name="key">Key to add.</param>
/// <param name="value">Value to associate with key.</param>
/// <param name="overwrite">If true, will overwrite an existing key.</param>
private void Add(long key, TValue value, bool overwrite)
{
if (null != this.readerWriterLock)
{
this.readerWriterLock.EnterWriteLock();
}
try
{
MemoryCacheEntry extantEntry;
if (this.dictionary.TryGetValue(key, out extantEntry))
{
if (!overwrite)
{
return;
}
// We already have an entry for this key. Update the entry
// with the new value and exit.
extantEntry.Value = value;
}
else if (this.dictionary.Count < this.maxSize)
{
// The cache is still growing -- we do not need an eviction to add this entry.
MemoryCacheEntry newEntry = new MemoryCacheEntry(key, value);
this.dictionary.Add(key, newEntry);
this.sortedList.Add(newEntry);
}
}
finally
{
if (null != this.readerWriterLock)
{
this.readerWriterLock.ExitWriteLock();
}
}
}
public void Update(MemoryCacheEntry entry)
{
base.Remove(entry);
entry.UtcLastUpdateUsage = DateTime.UtcNow;
base.Add(entry);
}
public void Remove(MemoryCacheEntry entry)
{
base.Remove(entry);
entry.UsageEntryRef = UsageEntryRef.INVALID;
}
public DateTime GetDateTime(MemoryCacheEntry entry)
{
return(entry.UtcLastUpdateUsage);
}
public void Update (MemoryCacheEntry entry)
{
base.Remove (entry);
entry.UtcLastUpdateUsage = DateTime.UtcNow;
base.Add (entry);
}
public new void Remove (MemoryCacheEntry entry)
{
base.Remove (entry);
entry.UsageEntryRef = UsageEntryRef.INVALID;
}
public DateTime GetDateTime (MemoryCacheEntry entry)
{
return entry.UtcLastUpdateUsage;
}
/// <summary>
/// Adds the specified key and value to the dictionary.
/// </summary>
/// <param name="key">Key to add</param>
/// <param name="value">Value to associate with key</param>
/// <param name="overwrite">If true, will overwrite an existing key</param>
/// <returns>True if the key was successfully added; false if the key was already in the dictionary</returns>
private bool AddHelper(TKey key, TValue value, bool overwrite)
{
m_readerWriterLock.EnterWriteLock();
try
{
MemoryCacheEntry <TKey, TValue> extantEntry;
if (m_dictionary.TryGetValue(key, out extantEntry))
{
if (!overwrite)
{
return(false);
}
// We already have an entry for this key. Update the entry
// with the new value and exit.
extantEntry.Value = value;
}
else if (m_currentSize < m_maxSize)
{
// The cache is still growing -- we do not need an eviction to add this entry.
MemoryCacheEntry <TKey, TValue> newEntry = new MemoryCacheEntry <TKey, TValue>(key, value);
m_dictionary[key] = newEntry;
if (null == m_beforeClockHand)
{
// currentSize transitioning from 0 to 1.
newEntry.Next = newEntry;
newEntry.Previous = newEntry;
}
else
{
// currentSize transitioning from >= 1 to maxSize.
newEntry.Next = m_beforeClockHand.Next;
newEntry.Previous = m_beforeClockHand;
m_beforeClockHand.Next.Previous = newEntry;
m_beforeClockHand.Next = newEntry;
}
m_beforeClockHand = newEntry;
m_currentSize++;
Debug.Assert(m_currentSize == m_dictionary.Count);
}
else
{
// The cache is full and we need to evict in order to add this entry.
// beforeClockHand.Next is the clock hand in the clock replacement algorithm.
MemoryCacheEntry <TKey, TValue> clockHand = m_beforeClockHand.Next;
while (clockHand.Referenced)
{
clockHand.Referenced = false;
clockHand = clockHand.Next;
}
// clockHand now points to the entry we will evict. We will re-use
// the existing cache entry.
m_dictionary.Remove(clockHand.Key);
clockHand.Key = key;
clockHand.Value = value;
clockHand.Referenced = false;
m_dictionary[key] = clockHand;
// Save the new clock hand position.
m_beforeClockHand = clockHand;
}
}
finally
{
m_readerWriterLock.ExitWriteLock();
}
return(true);
}
/// <summary>
/// Implemented in derived classes to add a new entry to the cache
/// </summary>
/// <param name="key">The key for the new entry</param>
/// <param name="data">The data for the new entry</param>
/// <param name="cachePriority">The entry priority</param>
/// <returns>The newly created cache entry</returns>
protected override AbstractCacheEntry AddEntry(string key, byte[] data, CachePriority cachePriority)
{
var entry = new MemoryCacheEntry(key, data, cachePriority);
_cache.AddOrUpdate(key, entry, (k, e) => entry);
return entry;
}
