Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / clr / src / BCL / System / _LocalDataStore.cs / 1305376 / _LocalDataStore.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== /*============================================================================== ** ** Class: LocalDataStore ** ** ** Purpose: Class that stores local data. This class is used in cooperation ** with the _LocalDataStoreMgr class. ** ** =============================================================================*/ namespace System { using System; using System.Threading; using System.Runtime.CompilerServices; using System.Diagnostics.Contracts; // Helper class to aid removal of LocalDataStore from the LocalDataStoreMgr // LocalDataStoreMgr does not holds references to LocalDataStoreHolder. It holds // references to LocalDataStore only. LocalDataStoreHolder finalizer will run once // the only outstanding reference to the store is in LocalDataStoreMgr. sealed internal class LocalDataStoreHolder { private LocalDataStore m_Store; public LocalDataStoreHolder(LocalDataStore store) { m_Store = store; } ~LocalDataStoreHolder() { LocalDataStore store = m_Store; if (store == null) return; store.Dispose(); } public LocalDataStore Store { get { return m_Store; } } } sealed internal class LocalDataStoreElement { private Object m_value; private long m_cookie; // This is immutable cookie of the slot used to verify that // the value is indeed indeed owned by the slot. Necessary // to avoid resurection holes. public LocalDataStoreElement(long cookie) { m_cookie = cookie; } public Object Value { get { return m_value; } set { m_value = value; } } public long Cookie { get { return m_cookie; } } } // This class will not be marked serializable sealed internal class LocalDataStore { private LocalDataStoreElement[] m_DataTable; private LocalDataStoreMgr m_Manager; /*========================================================================= ** Initialize the data store. =========================================================================*/ public LocalDataStore(LocalDataStoreMgr mgr, int InitialCapacity) { // Store the manager of the local data store. m_Manager = mgr; // Allocate the array that will contain the data. m_DataTable = new LocalDataStoreElement[InitialCapacity]; } /*========================================================================= ** Delete this store from its manager =========================================================================*/ internal void Dispose() { m_Manager.DeleteLocalDataStore(this); } /*========================================================================= ** Retrieves the value from the specified slot. =========================================================================*/ public Object GetData(LocalDataStoreSlot slot) { // Validate the slot. m_Manager.ValidateSlot(slot); // Cache the slot index to avoid synchronization issues. int slotIdx = slot.Slot; if (slotIdx >= 0) { // Delay expansion of m_DataTable if we can if (slotIdx >= m_DataTable.Length) return null; // Retrieve the data from the given slot. LocalDataStoreElement element = m_DataTable[slotIdx]; //Initially we prepopulate the elements to be null. if (element == null) return null; // Check that the element is owned by this slot by comparing cookies. // This is necesary to avoid resurection ----s. if (element.Cookie == slot.Cookie) return element.Value; // Fall thru and throw exception } throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_SlotHasBeenFreed")); } /*========================================================================== ** Sets the data in the specified slot. =========================================================================*/ public void SetData(LocalDataStoreSlot slot, Object data) { // Validate the slot. m_Manager.ValidateSlot(slot); // Cache the slot index to avoid synchronization issues. int slotIdx = slot.Slot; if (slotIdx >= 0) { LocalDataStoreElement element = (slotIdx < m_DataTable.Length) ? m_DataTable[slotIdx] : null; if (element == null) { element = PopulateElement(slot); } // Check that the element is owned by this slot by comparing cookies. // This is necesary to avoid resurection ----s. if (element.Cookie == slot.Cookie) { // Set the data on the given slot. element.Value = data; return; } // Fall thru and throw exception } throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_SlotHasBeenFreed")); } /*========================================================================= ** This method does clears the unused slot. * Assumes lock on m_Manager is taken =========================================================================*/ internal void FreeData(int slot, long cookie) { // We try to delay allocate the dataTable (in cases like the manager clearing a // just-freed slot in all stores if (slot >= m_DataTable.Length) return; LocalDataStoreElement element = m_DataTable[slot]; if (element != null && element.Cookie == cookie) m_DataTable[slot] = null; } /*========================================================================== ** Method used to expand the capacity of the local data store. =========================================================================*/ [System.Security.SecuritySafeCritical] // auto-generated private LocalDataStoreElement PopulateElement(LocalDataStoreSlot slot) { bool tookLock = false; RuntimeHelpers.PrepareConstrainedRegions(); try { Monitor.Enter(m_Manager, ref tookLock); // Make sure that the slot was not freed in the meantime int slotIdx = slot.Slot; if (slotIdx < 0) throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_SlotHasBeenFreed")); if (slotIdx >= m_DataTable.Length) { int capacity = m_Manager.GetSlotTableLength(); // Validate that the specified capacity is larger than the current one. Contract.Assert(capacity >= m_DataTable.Length, "LocalDataStore corrupted: capacity >= m_DataTable.Length"); // Allocate the new data table. LocalDataStoreElement[] NewDataTable = new LocalDataStoreElement[capacity]; // Copy all the objects into the new table. Array.Copy(m_DataTable, NewDataTable, m_DataTable.Length); // Save the new table. m_DataTable = NewDataTable; } // Validate that there is enough space in the local data store now Contract.Assert(slotIdx < m_DataTable.Length, "LocalDataStore corrupted: slotIdx < m_DataTable.Length"); if (m_DataTable[slotIdx] == null) m_DataTable[slotIdx] = new LocalDataStoreElement(slot.Cookie); return m_DataTable[slotIdx]; } finally { if (tookLock) Monitor.Exit(m_Manager); } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
Link Menu
![Network programming in C#, Network Programming in VB.NET, Network Programming in .NET](/images/book.jpg)
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- Error.cs
- XmlSchemaParticle.cs
- ResourceProviderFactory.cs
- DropTarget.cs
- MessageHeaders.cs
- grammarelement.cs
- InstanceCreationEditor.cs
- ItemsPanelTemplate.cs
- PropertyValueChangedEvent.cs
- TargetConverter.cs
- HandlerBase.cs
- DbDataAdapter.cs
- CodeCompileUnit.cs
- DataGridParentRows.cs
- DataGridViewColumnTypePicker.cs
- Roles.cs
- AsyncStreamReader.cs
- NotSupportedException.cs
- BooleanConverter.cs
- TranslateTransform.cs
- QueryableFilterRepeater.cs
- DataControlLinkButton.cs
- PermissionRequestEvidence.cs
- DATA_BLOB.cs
- ZoneButton.cs
- EventPrivateKey.cs
- DetailsViewPageEventArgs.cs
- ReaderContextStackData.cs
- NumericUpDownAccelerationCollection.cs
- AttributeParameterInfo.cs
- ProfileParameter.cs
- DBConnection.cs
- ApplicationManager.cs
- DeobfuscatingStream.cs
- RuntimeConfigLKG.cs
- GeneralTransform2DTo3D.cs
- AdornerDecorator.cs
- WebPartRestoreVerb.cs
- SmiSettersStream.cs
- FormatConvertedBitmap.cs
- ISFTagAndGuidCache.cs
- TextParentUndoUnit.cs
- DataGridViewSortCompareEventArgs.cs
- FastEncoderWindow.cs
- BlockUIContainer.cs
- ExpressionReplacer.cs
- MappingModelBuildProvider.cs
- DeflateStream.cs
- HtmlControlPersistable.cs
- SmiGettersStream.cs
- DataTable.cs
- Command.cs
- DependencyPropertyChangedEventArgs.cs
- Int32Rect.cs
- Missing.cs
- ErrorFormatter.cs
- ForceCopyBuildProvider.cs
- ImageBrush.cs
- RegexNode.cs
- _AutoWebProxyScriptEngine.cs
- QuaternionAnimationUsingKeyFrames.cs
- SynchronizedDispatch.cs
- Comparer.cs
- ForeignConstraint.cs
- WebMessageEncodingElement.cs
- IsolatedStoragePermission.cs
- CodeGotoStatement.cs
- WriteableOnDemandStream.cs
- GenericUI.cs
- XmlCollation.cs
- TreeNodeEventArgs.cs
- CompiledIdentityConstraint.cs
- StatusBarPanel.cs
- NavigationPropertyEmitter.cs
- CreateSequenceResponse.cs
- WebProxyScriptElement.cs
- EraserBehavior.cs
- AccessibleObject.cs
- CodeTypeReference.cs
- EntityDataSourceConfigureObjectContext.cs
- DataListItemCollection.cs
- Delegate.cs
- InheritanceContextChangedEventManager.cs
- UniqueEventHelper.cs
- WhereQueryOperator.cs
- FontFamilyIdentifier.cs
- SymLanguageType.cs
- ChameleonKey.cs
- WorkItem.cs
- WebPartConnectionsConnectVerb.cs
- XPathChildIterator.cs
- SimpleTableProvider.cs
- TextRangeEditLists.cs
- DataGridViewCheckBoxCell.cs
- InfoCardSymmetricAlgorithm.cs
- ConfigurationPropertyAttribute.cs
- MarkupProperty.cs
- Freezable.cs
- ProcessModuleCollection.cs
- FormsAuthenticationUserCollection.cs