Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / System.Runtime.DurableInstancing / System / Runtime / MruCache.cs / 1305376 / MruCache.cs
//------------------------------------------------------------ // Copyright (c) Microsoft Corporation. All rights reserved. //----------------------------------------------------------- namespace System.Runtime { using System.Collections.Generic; class MruCachewhere TKey : class where TValue : class { LinkedList mruList; Dictionary items; int lowWatermark; int highWatermark; CacheEntry mruEntry; public MruCache(int watermark) : this(watermark * 4 / 5, watermark) { } // // The cache will grow until the high watermark. At which point, the least recently used items // will be purge until the cache's size is reduced to low watermark // public MruCache(int lowWatermark, int highWatermark) : this(lowWatermark, highWatermark, null) { } public MruCache(int lowWatermark, int highWatermark, IEqualityComparer comparer) { Fx.Assert(lowWatermark < highWatermark, ""); Fx.Assert(lowWatermark >= 0, ""); this.lowWatermark = lowWatermark; this.highWatermark = highWatermark; this.mruList = new LinkedList (); if (comparer == null) { this.items = new Dictionary (); } else { this.items = new Dictionary (comparer); } } public void Add(TKey key, TValue value) { Fx.Assert(null != key, ""); // if anything goes wrong (duplicate entry, etc) we should // clear our caches so that we don't get out of [....] bool success = false; try { if (this.items.Count == this.highWatermark) { // If the cache is full, purge enough LRU items to shrink the // cache down to the low watermark int countToPurge = this.highWatermark - this.lowWatermark; for (int i = 0; i < countToPurge; i++) { TKey keyRemove = this.mruList.Last.Value; this.mruList.RemoveLast(); TValue item = this.items[keyRemove].value; this.items.Remove(keyRemove); OnSingleItemRemoved(item); } } // Add the new entry to the cache and make it the MRU element CacheEntry entry; entry.node = this.mruList.AddFirst(key); entry.value = value; this.items.Add(key, entry); this.mruEntry = entry; success = true; } finally { if (!success) { this.Clear(); } } } public void Clear() { this.mruList.Clear(); this.items.Clear(); this.mruEntry.value = null; this.mruEntry.node = null; } public bool Remove(TKey key) { Fx.Assert(null != key, ""); CacheEntry entry; if (this.items.TryGetValue(key, out entry)) { this.items.Remove(key); OnSingleItemRemoved(entry.value); this.mruList.Remove(entry.node); if (object.ReferenceEquals(this.mruEntry.node, entry.node)) { this.mruEntry.value = null; this.mruEntry.node = null; } return true; } return false; } protected virtual void OnSingleItemRemoved(TValue item) { } // // If found, make the entry most recently used // public bool TryGetValue(TKey key, out TValue value) { // first check our MRU item if (this.mruEntry.node != null && key != null && key.Equals(this.mruEntry.node.Value)) { value = this.mruEntry.value; return true; } CacheEntry entry; bool found = this.items.TryGetValue(key, out entry); value = entry.value; // Move the node to the head of the MRU list if it's not already there if (found && this.mruList.Count > 1 && !object.ReferenceEquals(this.mruList.First, entry.node)) { this.mruList.Remove(entry.node); this.mruList.AddFirst(entry.node); this.mruEntry = entry; } return found; } struct CacheEntry { internal TValue value; internal LinkedListNode node; } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. //------------------------------------------------------------ // Copyright (c) Microsoft Corporation. All rights reserved. //----------------------------------------------------------- namespace System.Runtime { using System.Collections.Generic; class MruCache where TKey : class where TValue : class { LinkedList mruList; Dictionary items; int lowWatermark; int highWatermark; CacheEntry mruEntry; public MruCache(int watermark) : this(watermark * 4 / 5, watermark) { } // // The cache will grow until the high watermark. At which point, the least recently used items // will be purge until the cache's size is reduced to low watermark // public MruCache(int lowWatermark, int highWatermark) : this(lowWatermark, highWatermark, null) { } public MruCache(int lowWatermark, int highWatermark, IEqualityComparer comparer) { Fx.Assert(lowWatermark < highWatermark, ""); Fx.Assert(lowWatermark >= 0, ""); this.lowWatermark = lowWatermark; this.highWatermark = highWatermark; this.mruList = new LinkedList (); if (comparer == null) { this.items = new Dictionary (); } else { this.items = new Dictionary (comparer); } } public void Add(TKey key, TValue value) { Fx.Assert(null != key, ""); // if anything goes wrong (duplicate entry, etc) we should // clear our caches so that we don't get out of [....] bool success = false; try { if (this.items.Count == this.highWatermark) { // If the cache is full, purge enough LRU items to shrink the // cache down to the low watermark int countToPurge = this.highWatermark - this.lowWatermark; for (int i = 0; i < countToPurge; i++) { TKey keyRemove = this.mruList.Last.Value; this.mruList.RemoveLast(); TValue item = this.items[keyRemove].value; this.items.Remove(keyRemove); OnSingleItemRemoved(item); } } // Add the new entry to the cache and make it the MRU element CacheEntry entry; entry.node = this.mruList.AddFirst(key); entry.value = value; this.items.Add(key, entry); this.mruEntry = entry; success = true; } finally { if (!success) { this.Clear(); } } } public void Clear() { this.mruList.Clear(); this.items.Clear(); this.mruEntry.value = null; this.mruEntry.node = null; } public bool Remove(TKey key) { Fx.Assert(null != key, ""); CacheEntry entry; if (this.items.TryGetValue(key, out entry)) { this.items.Remove(key); OnSingleItemRemoved(entry.value); this.mruList.Remove(entry.node); if (object.ReferenceEquals(this.mruEntry.node, entry.node)) { this.mruEntry.value = null; this.mruEntry.node = null; } return true; } return false; } protected virtual void OnSingleItemRemoved(TValue item) { } // // If found, make the entry most recently used // public bool TryGetValue(TKey key, out TValue value) { // first check our MRU item if (this.mruEntry.node != null && key != null && key.Equals(this.mruEntry.node.Value)) { value = this.mruEntry.value; return true; } CacheEntry entry; bool found = this.items.TryGetValue(key, out entry); value = entry.value; // Move the node to the head of the MRU list if it's not already there if (found && this.mruList.Count > 1 && !object.ReferenceEquals(this.mruList.First, entry.node)) { this.mruList.Remove(entry.node); this.mruList.AddFirst(entry.node); this.mruEntry = entry; } return found; } struct CacheEntry { internal TValue value; internal LinkedListNode node; } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- ElapsedEventArgs.cs
- GlyphTypeface.cs
- StatusBarPanelClickEvent.cs
- ValueProviderWrapper.cs
- TextRange.cs
- NamedPipeHostedTransportConfiguration.cs
- TypeBuilder.cs
- DataServiceQueryException.cs
- ExecutionContext.cs
- OleTxTransaction.cs
- PolicyException.cs
- RuntimeConfigurationRecord.cs
- SpecialNameAttribute.cs
- OptimalTextSource.cs
- CatalogZone.cs
- MetadataWorkspace.cs
- InfoCardProofToken.cs
- entityreference_tresulttype.cs
- TextEditorContextMenu.cs
- WebPartMinimizeVerb.cs
- SqlRemoveConstantOrderBy.cs
- FieldAccessException.cs
- Trace.cs
- Pair.cs
- ListenerSingletonConnectionReader.cs
- RoleGroupCollectionEditor.cs
- DbMetaDataFactory.cs
- TextServicesManager.cs
- Formatter.cs
- StorageConditionPropertyMapping.cs
- BaseTemplateCodeDomTreeGenerator.cs
- GridViewHeaderRowPresenterAutomationPeer.cs
- SplineQuaternionKeyFrame.cs
- ISCIIEncoding.cs
- WebControl.cs
- NegotiateStream.cs
- Emitter.cs
- DynamicDocumentPaginator.cs
- SchemaCollectionCompiler.cs
- Itemizer.cs
- StatusStrip.cs
- TcpTransportSecurity.cs
- TreeNode.cs
- AutomationIdentifier.cs
- MimeTypeMapper.cs
- MediaSystem.cs
- LayoutInformation.cs
- SubMenuStyleCollection.cs
- StringHandle.cs
- FactoryId.cs
- ObjectSecurity.cs
- InternalConfigConfigurationFactory.cs
- TimeZone.cs
- MetadataProperty.cs
- XmlSequenceWriter.cs
- MatrixCamera.cs
- ChildrenQuery.cs
- StateBag.cs
- HtmlButton.cs
- ExpandedWrapper.cs
- SqlBuffer.cs
- LogEntry.cs
- LineSegment.cs
- PermissionAttributes.cs
- EventSinkHelperWriter.cs
- IndexedGlyphRun.cs
- DBConcurrencyException.cs
- DecoderFallback.cs
- SyntaxCheck.cs
- TableLayoutPanel.cs
- PanelStyle.cs
- FormViewPagerRow.cs
- FormsAuthenticationConfiguration.cs
- XmlBindingWorker.cs
- PageMediaType.cs
- InkCanvasAutomationPeer.cs
- ResourceManager.cs
- FlowchartDesigner.xaml.cs
- ItemPager.cs
- PageFunction.cs
- Image.cs
- SafeProcessHandle.cs
- GenericsInstances.cs
- HttpModuleActionCollection.cs
- HttpCookie.cs
- PerspectiveCamera.cs
- StorageComplexTypeMapping.cs
- SmtpAuthenticationManager.cs
- Style.cs
- DependencyPropertyHelper.cs
- SchemaSetCompiler.cs
- InterleavedZipPartStream.cs
- DependentTransaction.cs
- SmtpReplyReader.cs
- SHA512.cs
- ObjectTypeMapping.cs
- TemplateBindingExpressionConverter.cs
- EventArgs.cs
- StateBag.cs
- HttpWebResponse.cs