// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
namespace MS.Internal.Xml.XPath
{
using System;
using Microsoft.Xml;
using Microsoft.Xml.XPath;
using System.Diagnostics;
using Microsoft.Xml.Xsl;
using System.Collections.Generic;
internal abstract class CacheOutputQuery : Query
{
internal Query input;
// int count; -- we reusing it here
protected List<XPathNavigator> outputBuffer;
public CacheOutputQuery(Query input)
{
this.input = input;
this.outputBuffer = new List<XPathNavigator>();
this.count = 0;
}
protected CacheOutputQuery(CacheOutputQuery other) : base(other)
{
this.input = Clone(other.input);
this.outputBuffer = new List<XPathNavigator>(other.outputBuffer);
this.count = other.count;
}
public override void Reset()
{
this.count = 0;
}
public override void SetXsltContext(XsltContext context)
{
input.SetXsltContext(context);
}
public override object Evaluate(XPathNodeIterator context)
{
outputBuffer.Clear();
count = 0;
return input.Evaluate(context);// This is trick. IDQuery needs this value. Otherwise we would return this.
// All subclasses should and would anyway override thismethod and return this.
}
public override XPathNavigator Advance()
{
Debug.Assert(0 <= count && count <= outputBuffer.Count);
if (count < outputBuffer.Count)
{
return outputBuffer[count++];
}
return null;
}
public override XPathNavigator Current
{
get
{
Debug.Assert(0 <= count && count <= outputBuffer.Count);
if (count == 0)
{
return null;
}
return outputBuffer[count - 1];
}
}
public override XPathResultType StaticType { get { return XPathResultType.NodeSet; } }
public override int CurrentPosition { get { return count; } }
public override int Count { get { return outputBuffer.Count; } }
public override QueryProps Properties { get { return QueryProps.Merge | QueryProps.Cached | QueryProps.Position | QueryProps.Count; } }
public override void PrintQuery(XmlWriter w)
{
w.WriteStartElement(this.GetType().Name);
input.PrintQuery(w);
w.WriteEndElement();
}
}
}
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