Author: atsushi
Date: 2005-03-25 05:56:11 -0500 (Fri, 25 Mar 2005)
New Revision: 42247
Modified:
trunk/mcs/class/System.XML/System.Xml.XPath/ChangeLog
trunk/mcs/class/System.XML/System.Xml.XPath/Expression.cs
Log:
2004-03-25 Atsushi Enomoto <[EMAIL PROTECTED]>
* Expression.cs : In ExprSLASH2, replace A//B with A/descendant::B if
B is child axis test (thus peer&subtree optimization became possible)
Fixed warning (incorrect variable let).
Modified: trunk/mcs/class/System.XML/System.Xml.XPath/ChangeLog
===================================================================
--- trunk/mcs/class/System.XML/System.Xml.XPath/ChangeLog 2005-03-25
05:35:58 UTC (rev 42246)
+++ trunk/mcs/class/System.XML/System.Xml.XPath/ChangeLog 2005-03-25
10:56:11 UTC (rev 42247)
@@ -1,5 +1,11 @@
2004-03-25 Atsushi Enomoto <[EMAIL PROTECTED]>
+ * Expression.cs : In ExprSLASH2, replace A//B with A/descendant::B if
+ B is child axis test (thus peer&subtree optimization became possible)
+ Fixed warning (incorrect variable let).
+
+2004-03-25 Atsushi Enomoto <[EMAIL PROTECTED]>
+
* XPathNavigator.cs : reduced some Clone().
Simplified ComparePosition().
* Iterator.cs : some iterators are not actually reverse axis.
Modified: trunk/mcs/class/System.XML/System.Xml.XPath/Expression.cs
===================================================================
--- trunk/mcs/class/System.XML/System.Xml.XPath/Expression.cs 2005-03-25
05:35:58 UTC (rev 42246)
+++ trunk/mcs/class/System.XML/System.Xml.XPath/Expression.cs 2005-03-25
10:56:11 UTC (rev 42247)
@@ -469,6 +469,8 @@
get { return false; }
}
+ // For "peer and subtree" optimization. see:
+ //
http://idealliance.org/papers/dx_xmle04/papers/02-03-02/02-03-02.html
internal virtual bool Peer {
get { return false; }
}
@@ -1084,6 +1086,8 @@
{
public override XPathResultType ReturnType { get { return
XPathResultType.NodeSet; }}
+ // For "peer and subtree" optimization. see:
+ //
http://idealliance.org/papers/dx_xmle04/papers/02-03-02/02-03-02.html
internal abstract bool Subtree { get; }
}
@@ -1152,6 +1156,8 @@
public override String ToString () { return left.ToString ()+
"/" + right.ToString (); }
public override object Evaluate (BaseIterator iter)
{
+ // Peer and subtree optimization. see
+ //
http://idealliance.org/papers/dx_xmle04/papers/02-03-02/02-03-02.html
BaseIterator iterLeft = left.EvaluateNodeSet (iter);
if (left.Peer && right.Subtree && !RequireSorting)
return new SimpleSlashIterator (iterLeft,
right);
@@ -1196,18 +1202,38 @@
{
left = left.Optimize ();
right = (NodeSet) right.Optimize ();
+ // Path A//B is equal to
+ // A/descendant-or-self::node()/child::B, which is
+ // equivalent to A/descendant::B. Unlike '//', '/'
+ // could be optimized by SimpleSlashIterator.
+ NodeTest rnt = right as NodeTest;
+ if (rnt != null && rnt.Axis.Axis == Axes.Child) {
+ NodeNameTest nameTest = rnt as NodeNameTest;
+ if (nameTest != null)
+ return new ExprSLASH (left,
+ new NodeNameTest (nameTest,
Axes.Descendant));
+ NodeTypeTest typeTest = rnt as NodeTypeTest;
+ if (typeTest != null)
+ return new ExprSLASH (left,
+ new NodeTypeTest (typeTest,
Axes.Descendant));
+ }
return this;
}
public override String ToString () { return left.ToString ()+
"//" + right.ToString (); }
public override object Evaluate (BaseIterator iter)
{
+ BaseIterator il = left.EvaluateNodeSet (iter);
+ if (left.Peer && !left.RequireSorting)
+ il = new SimpleSlashIterator (
+ il, DescendantOrSelfStar);
+ else
+ il = new SlashIterator (il,
+ DescendantOrSelfStar,
+ left.RequireSorting);
+
return new SlashIterator (
- new SlashIterator (
- left.EvaluateNodeSet (iter),
- DescendantOrSelfStar,
- left.RequireSorting ||
DescendantOrSelfStar.RequireSorting
- ),
+ il,
right,
DescendantOrSelfStar.RequireSorting ||
right.RequireSorting
);
@@ -1460,6 +1486,14 @@
throw new XPathException ("No argument allowed
for "+ToString (type)+"() test"); // TODO: better description
}
+ // for optimizer use
+ internal NodeTypeTest (NodeTypeTest other, Axes axis)
+ : base (axis)
+ {
+ type = other.type;
+ _param = other._param;
+ }
+
public override String ToString ()
{
String strType = ToString (type);
@@ -1539,8 +1573,17 @@
public NodeNameTest (Axes axis, XmlQualifiedName name, bool
resolvedName) : base (axis)
{
_name = name;
- resolvedName = resolvedName;
+ this.resolvedName = resolvedName;
}
+
+ // for optimized path rewrite
+ internal NodeNameTest (NodeNameTest source, Axes axis)
+ : base (axis)
+ {
+ _name = source._name;
+ resolvedName = source.resolvedName;
+ }
+
public override String ToString () { return _axis.ToString () +
"::" + _name.ToString (); }
public XmlQualifiedName Name { get { return _name; } }
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