Code:
/ FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / fx / src / Xml / System / Xml / XPath / Internal / SortQuery.cs / 1 / SortQuery.cs
//------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //[....] //----------------------------------------------------------------------------- namespace MS.Internal.Xml.XPath { using System; using System.Xml; using System.Xml.XPath; using System.Xml.Xsl; using System.Diagnostics; using System.Collections; using System.Collections.Generic; internal sealed class SortQuery : Query { private Listresults; private XPathSortComparer comparer; private Query qyInput; public SortQuery(Query qyInput) { Debug.Assert(qyInput != null, "Sort Query needs an input query tree to work on"); this.results = new List (); this.comparer = new XPathSortComparer(); this.qyInput = qyInput; count = 0; } private SortQuery(SortQuery other) : base(other) { this.results = new List (other.results); this.comparer = other.comparer.Clone(); this.qyInput = Clone(other.qyInput); count = 0; } public override void Reset() { count = 0; } public override void SetXsltContext(XsltContext xsltContext) { qyInput.SetXsltContext(xsltContext); if ( qyInput.StaticType != XPathResultType.NodeSet && qyInput.StaticType != XPathResultType.Any ) { throw XPathException.Create(Res.Xp_NodeSetExpected); } } private void BuildResultsList() { Int32 numSorts = this.comparer.NumSorts; Debug.Assert(numSorts > 0, "Why was the sort query created?"); XPathNavigator eNext; while ((eNext = qyInput.Advance()) != null) { SortKey key = new SortKey(numSorts, /*originalPosition:*/this.results.Count, eNext.Clone()); for (Int32 j = 0; j < numSorts; j++) { key[j] = this.comparer.Expression(j).Evaluate(qyInput); } results.Add(key); } results.Sort(this.comparer); } public override object Evaluate(XPathNodeIterator context) { qyInput.Evaluate(context); this.results.Clear(); BuildResultsList(); count = 0; return this; } public override XPathNavigator Advance() { Debug.Assert(0 <= count && count <= results.Count); if (count < this.results.Count) { return this.results[count++].Node; } return null; } public override XPathNavigator Current { get { Debug.Assert(0 <= count && count <= results.Count); if (count == 0) { return null; } return results[count - 1].Node; } } internal void AddSort(Query evalQuery, IComparer comparer) { this.comparer.AddSort(evalQuery, comparer); } public override XPathNodeIterator Clone() { return new SortQuery(this); } public override XPathResultType StaticType { get { return XPathResultType.NodeSet; } } public override int CurrentPosition { get { return count; } } public override int Count { get { return results.Count; } } public override QueryProps Properties { get { return QueryProps.Cached | QueryProps.Position | QueryProps.Count; } } public override void PrintQuery(XmlWriter w) { w.WriteStartElement(this.GetType().Name); qyInput.PrintQuery(w); w.WriteElementString("XPathSortComparer", "... PrintTree() not implemented ..."); w.WriteEndElement(); } } // class SortQuery internal sealed class SortKey { private Int32 numKeys; private object[] keys; private int originalPosition; private XPathNavigator node; public SortKey(int numKeys, int originalPosition, XPathNavigator node) { this.numKeys = numKeys; this.keys = new object[numKeys]; this.originalPosition = originalPosition; this.node = node; } public object this[int index] { get { return this.keys[index]; } set { this.keys[index] = value; } } public int NumKeys { get { return this.numKeys; } } public int OriginalPosition { get { return this.originalPosition; } } public XPathNavigator Node { get { return this.node; } } } // class SortKey internal sealed class XPathSortComparer : IComparer { private const int minSize = 3; private Query[] expressions; private IComparer[] comparers; private int numSorts; public XPathSortComparer(int size) { if (size <= 0) size = minSize; this.expressions = new Query[ size]; this.comparers = new IComparer[size]; } public XPathSortComparer() : this (minSize) {} public void AddSort(Query evalQuery, IComparer comparer) { Debug.Assert(this.expressions.Length == this.comparers.Length); Debug.Assert(0 < this.expressions.Length); Debug.Assert(0 <= numSorts && numSorts <= this.expressions.Length); // Ajust array sizes if needed. if (numSorts == this.expressions.Length) { Query[] newExpressions = new Query[ numSorts * 2]; IComparer[] newComparers = new IComparer[numSorts * 2]; for (int i = 0; i < numSorts; i ++) { newExpressions[i] = this.expressions[i]; newComparers [i] = this.comparers[i]; } this.expressions = newExpressions; this.comparers = newComparers; } Debug.Assert(numSorts < this.expressions.Length); // Fixup expression to handle node-set return type: if (evalQuery.StaticType == XPathResultType.NodeSet || evalQuery.StaticType == XPathResultType.Any) { evalQuery = new StringFunctions(Function.FunctionType.FuncString, new Query[] { evalQuery }); } this.expressions[numSorts] = evalQuery; this.comparers[ numSorts] = comparer; numSorts ++; } public int NumSorts { get { return numSorts; } } public Query Expression(int i) { return this.expressions[i]; } int IComparer .Compare(SortKey x, SortKey y) { Debug.Assert(x != null && y != null, "Oops!! what happened?"); int result = 0; for (int i = 0; i < x.NumKeys; i++) { result = this.comparers[i].Compare(x[i], y[i]); if (result != 0) { return result; } } // if after all comparisions, the two sort keys are still equal, preserve the doc order return x.OriginalPosition - y.OriginalPosition; } internal XPathSortComparer Clone() { XPathSortComparer clone = new XPathSortComparer(this.numSorts); for (int i = 0; i < this.numSorts; i ++) { clone.comparers[i] = this.comparers[i]; clone.expressions[i] = (Query)this.expressions[i].Clone(); // Expressions should be cloned because Query should be cloned } clone.numSorts = this.numSorts; return clone; } } // class XPathSortComparer } // namespace // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. 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