Code:
/ DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Framework / System / Windows / Documents / TextElementCollectionHelper.cs / 1 / TextElementCollectionHelper.cs
//---------------------------------------------------------------------------- // // Copyright (C) Microsoft Corporation. All rights reserved. // // Description: Static methods for all TextElementCollectioninstances. // //--------------------------------------------------------------------------- namespace System.Windows.Documents { // This class maintains a static list of "clean" TextElementCollection // instances. Clean in this sense means guarantee not to have been // modified in a way that could invalidate their _indexCache members. // // The cache is a simple list of WeakReferences to collections. // The size of the list limits the number of collections // that can be used to modify content simultaneously with good IList // performance. The scenario we're concerned about is the parser, // which will allocate one collection for each scoping TextElement // in a document: // requires a minimum cache size of 3 to keep load times O(n). internal static class TextElementCollectionHelper { //------------------------------------------------------------------- // // Internal Methods // //------------------------------------------------------------------- #region Internal Methods // Invalidates any collection tracking parent's children. // Called by the TextContainer. internal static void MarkDirty(DependencyObject parent) { if (parent == null) { return; } lock (_cleanParentList) { for (int i = 0; i < _cleanParentList.Length; i++) { if (_cleanParentList[i] != null) { ParentCollectionPair pair = (ParentCollectionPair)_cleanParentList[i].Target; if (pair == null || pair.Parent == parent) { _cleanParentList[i] = null; } } } } } // Tags a parent/collection as synchronized. // Since we use a most-recently-used algorithm, it's useful // to call this any time a collection is touched, even if it is // only read. internal static void MarkClean(DependencyObject parent, object collection) { lock (_cleanParentList) { int firstFreeIndex; int index = GetCleanParentIndex(parent, collection, out firstFreeIndex); if (index == -1) { index = firstFreeIndex >= 0 ? firstFreeIndex : _cleanParentList.Length - 1; _cleanParentList[index] = new WeakReference(new ParentCollectionPair(parent, collection)); } TouchCleanParent(index); } } // Returns true if the parent/collection pair are clean. // Since we use a most-recently-used algorithm, it's useful // to call this any time a collection is touched, even if it is // only read. internal static bool IsCleanParent(DependencyObject parent, object collection) { int index = -1; lock (_cleanParentList) { int firstFreeIndex; index = GetCleanParentIndex(parent, collection, out firstFreeIndex); if (index >= 0) { TouchCleanParent(index); } } return (index >= 0); } #endregion Internal Methods //-------------------------------------------------------------------- // // Private Methods // //------------------------------------------------------------------- #region Private Methods // Moves an entry to the top of the most-recently-used list. // Caller must hold a lock on _cleanParentList! private static void TouchCleanParent(int index) { WeakReference parentReference = _cleanParentList[index]; // Shift preceding parents down, dropping the last parent. Array.Copy(_cleanParentList, 0, _cleanParentList, 1, index); // Put the mru parent at the head. _cleanParentList[0] = parentReference; } // Returns the index of an entry in the list, or -1 if not present. // Caller must hold a lock on _cleanParentList! private static int GetCleanParentIndex(DependencyObject parent, object collection, out int firstFreeIndex) { int index = -1; firstFreeIndex = -1; for (int i = 0; i < _cleanParentList.Length; i++) { if (_cleanParentList[i] == null) { if (firstFreeIndex == -1) { firstFreeIndex = i; } } else { ParentCollectionPair pair = (ParentCollectionPair)_cleanParentList[i].Target; if (pair == null) { // WeakReference is dead, remove it. _cleanParentList[i] = null; if (firstFreeIndex == -1) { firstFreeIndex = i; } } else if (pair.Parent == parent && pair.Collection == collection) { // Found a match. Keep going to clean up any dead WeakReferences // or set firstFreeIndex. index = i; } } } return index; } #endregion Private Methods //-------------------------------------------------------------------- // // Private Types // //-------------------------------------------------------------------- #region Private Types // A parent/collection entry. private class ParentCollectionPair { internal ParentCollectionPair(DependencyObject parent, object collection) { _parent = parent; _collection = collection; } internal DependencyObject Parent { get { return _parent; } } internal object Collection { get { return _collection; } } private readonly DependencyObject _parent; private readonly object _collection; } #endregion Private Types //------------------------------------------------------------------- // // Private Fields // //-------------------------------------------------------------------- #region Private Fields // Static list of clean parent/collection pairs. private static readonly WeakReference []_cleanParentList = new WeakReference[10]; #endregion Private Fields } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved. hello world
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- XmlImplementation.cs
- TextTreeExtractElementUndoUnit.cs
- MarkupCompiler.cs
- EntityContainer.cs
- CustomAttribute.cs
- iisPickupDirectory.cs
- SerializableAttribute.cs
- DataRowExtensions.cs
- DataMisalignedException.cs
- SchemaNotation.cs
- ParseElement.cs
- _NetworkingPerfCounters.cs
- CqlErrorHelper.cs
- ByteKeyFrameCollection.cs
- TypeConverterMarkupExtension.cs
- XComponentModel.cs
- ExpressionStringBuilder.cs
- OleDbError.cs
- MessageLogTraceRecord.cs
- MSHTMLHost.cs
- xsdvalidator.cs
- Compilation.cs
- ComponentCommands.cs
- DataGridViewHeaderCell.cs
- ContextMenu.cs
- DataBoundControl.cs
- GenericRootAutomationPeer.cs
- RemoteArgument.cs
- WindowsStatic.cs
- HttpException.cs
- XmlAttributeHolder.cs
- UnknownExceptionActionHelper.cs
- DbProviderConfigurationHandler.cs
- TrackBarDesigner.cs
- nulltextcontainer.cs
- ReferencedCollectionType.cs
- Parser.cs
- Sql8ConformanceChecker.cs
- FamilyCollection.cs
- HoistedLocals.cs
- SR.cs
- HtmlGenericControl.cs
- FormattedText.cs
- FakeModelItemImpl.cs
- SessionEndingCancelEventArgs.cs
- XmlBindingWorker.cs
- TrustSection.cs
- _OSSOCK.cs
- AudioDeviceOut.cs
- PingOptions.cs
- SiteIdentityPermission.cs
- TypeDescriptionProvider.cs
- EndOfStreamException.cs
- AttachedPropertyBrowsableForChildrenAttribute.cs
- InteropAutomationProvider.cs
- RouteItem.cs
- WindowsListView.cs
- AspCompat.cs
- DefaultAutoFieldGenerator.cs
- AuthenticationService.cs
- CalculatedColumn.cs
- ContainsRowNumberChecker.cs
- ToolStripMenuItem.cs
- MetadataItemEmitter.cs
- ItemType.cs
- AccessControlList.cs
- SafeNativeMethods.cs
- OdbcConnectionString.cs
- CheckBoxPopupAdapter.cs
- ContractsBCL.cs
- TcpServerChannel.cs
- PlaceHolder.cs
- ComEventsSink.cs
- Crypto.cs
- UnsafeNativeMethodsMilCoreApi.cs
- _NTAuthentication.cs
- DataSourceXmlElementAttribute.cs
- XmlSchemaInfo.cs
- Validator.cs
- CloseCryptoHandleRequest.cs
- safelink.cs
- IndexOutOfRangeException.cs
- TriggerAction.cs
- SqlDependencyUtils.cs
- Dump.cs
- MenuRenderer.cs
- TagMapInfo.cs
- IApplicationTrustManager.cs
- QueryableFilterUserControl.cs
- SimpleHandlerFactory.cs
- RemotingServices.cs
- DataGridViewToolTip.cs
- VisualStates.cs
- MetadataArtifactLoader.cs
- ZipIOZip64EndOfCentralDirectoryLocatorBlock.cs
- Vector3D.cs
- ListViewGroup.cs
- X509ScopedServiceCertificateElementCollection.cs
- EncryptedReference.cs
- PenLineJoinValidation.cs