Code:
/ DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Framework / MS / Internal / Data / AccessorTable.cs / 1 / AccessorTable.cs
//---------------------------------------------------------------------------- // //// Copyright (C) Microsoft Corporation. All rights reserved. // // // Description: Mapping of (SourceValueType, type, name) to (info, propertyType, args) // //--------------------------------------------------------------------------- /***************************************************************************\ Data binding uses reflection to obtain accessors for source properties, where an "accessor" can be a DependencyProperty, a PropertyInfo, or a PropertyDescriptor, depending on the nature of the source item and the property. We cache the result of this discovery process in the AccessorTable; table lookup is cheaper than doing reflection again. \***************************************************************************/ using System; using System.Collections; using System.ComponentModel; // IBindingList using System.Reflection; // TypeDescriptor using System.Windows; // SR using System.Windows.Threading; // Dispatcher using MS.Internal; // Invariant.Assert namespace MS.Internal.Data { internal sealed class AccessorInfo { internal AccessorInfo(object accessor, Type propertyType, object[] args) { _accessor = accessor; _propertyType = propertyType; _args = args; } internal object Accessor { get { return _accessor; } } internal Type PropertyType { get { return _propertyType; } } internal object[] Args { get { return _args; } } internal int Generation { get { return _generation; } set { _generation = value; } } object _accessor; // DP, PD, or PI Type _propertyType; // type of the property object[] _args; // args for indexed property int _generation; // used for discarding aged entries } internal sealed class AccessorTable { internal AccessorTable() { } // map (SourceValueType, type, name) to (accessor, propertyType, args) internal AccessorInfo this[SourceValueType sourceValueType, Type type, string name] { get { if (type == null || name == null) return null; AccessorInfo info = (AccessorInfo)_table[new AccessorTableKey(sourceValueType, type, name)]; if (info != null) { #if DEBUG // record the age of cache hits int age = _generation - info.Generation; if (age >= _ages.Length) { int[] newAges = new int[2*age]; _ages.CopyTo(newAges, 0); _ages = newAges; } ++ _ages[age]; ++ _hits; #endif info.Generation = _generation; } #if DEBUG else { ++ _misses; } #endif return info; } set { if (type != null && name != null) { value.Generation = _generation; _table[new AccessorTableKey(sourceValueType, type, name)] = value; if (!_cleanupRequested) RequestCleanup(); } } } // request a cleanup pass private void RequestCleanup() { _cleanupRequested = true; Dispatcher.CurrentDispatcher.BeginInvoke(DispatcherPriority.ContextIdle, new DispatcherOperationCallback(CleanupOperation), null); } // run a cleanup pass private object CleanupOperation(object arg) { // find entries that are sufficiently old object[] keysToRemove = new object[_table.Count]; int n = 0; IDictionaryEnumerator ide = _table.GetEnumerator(); while (ide.MoveNext()) { AccessorInfo info = (AccessorInfo)ide.Value; int age = _generation - info.Generation; if (age >= AgeLimit) { keysToRemove[n++] = ide.Key; } } #if DEBUG if (_traceSize) { Console.WriteLine("After generation {0}, removing {1} of {2} entries from AccessorTable, new count is {3}", _generation, n, _table.Count, _table.Count - n); } #endif // remove those entries for (int i=0; i0) { cumulativeHits += _ages[i]; Console.WriteLine("{0,5} {1,6} {2,5} {3,5}", i, _ages[i], 100*_ages[i]/_hits, 100*cumulativeHits/_hits); } } #endif } internal bool TraceSize { get { return _traceSize; } set { _traceSize = value; } } private const int AgeLimit = 10; // entries older than this get removed. private Hashtable _table = new Hashtable(); private int _generation; private bool _cleanupRequested; bool _traceSize; #if DEBUG private int[] _ages = new int[10]; private int _hits, _misses; #endif private struct AccessorTableKey { public AccessorTableKey(SourceValueType sourceValueType, Type type, string name) { Invariant.Assert(type != null && type != null); _sourceValueType = sourceValueType; _type = type; _name = name; } public override bool Equals(object o) { if (o is AccessorTableKey) return this == (AccessorTableKey)o; else return false; } public static bool operator==(AccessorTableKey k1, AccessorTableKey k2) { return k1._sourceValueType == k2._sourceValueType && k1._type == k2._type && k1._name == k2._name; } public static bool operator!=(AccessorTableKey k1, AccessorTableKey k2) { return !(k1 == k2); } public override int GetHashCode() { return unchecked(_type.GetHashCode() + _name.GetHashCode()); } SourceValueType _sourceValueType; Type _type; string _name; } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved.
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