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[Nhibernate-commit] SF.net SVN: nhibernate:[3705] trunk/nhibernate/src/NHibernate.Linq
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From: <te...@us...> - 2008-08-15 11:25:06
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Revision: 3705
http://nhibernate.svn.sourceforge.net/nhibernate/?rev=3705&view=rev
Author: tehlike
Date: 2008-08-15 11:25:15 +0000 (Fri, 15 Aug 2008)
Log Message:
-----------
-Copied Evaluator from Contrib and renamed it to LocalVariableExpressionReducer
Modified Paths:
--------------
trunk/nhibernate/src/NHibernate.Linq/NHibernate.Linq.csproj
trunk/nhibernate/src/NHibernate.Linq/NHibernateQueryProvider.cs
trunk/nhibernate/src/NHibernate.Linq/Query.cs
trunk/nhibernate/src/NHibernate.Linq/Visitors/LogicalExpressionReducer.cs
Added Paths:
-----------
trunk/nhibernate/src/NHibernate.Linq/Util/Guard.cs
trunk/nhibernate/src/NHibernate.Linq/Visitors/LocalVariableExpressionReducer.cs
Modified: trunk/nhibernate/src/NHibernate.Linq/NHibernate.Linq.csproj
===================================================================
--- trunk/nhibernate/src/NHibernate.Linq/NHibernate.Linq.csproj 2008-08-15 05:37:47 UTC (rev 3704)
+++ trunk/nhibernate/src/NHibernate.Linq/NHibernate.Linq.csproj 2008-08-15 11:25:15 UTC (rev 3705)
@@ -46,6 +46,7 @@
</ProjectReference>
</ItemGroup>
<ItemGroup>
+ <Compile Include="Util\Guard.cs" />
<Compile Include="Visitors\LogicalExpressionReducer.cs" />
<Compile Include="ExpressionVisitor.cs" />
<Compile Include="NHibernateExtensions.cs" />
@@ -53,6 +54,7 @@
<Compile Include="Query.cs" />
<Compile Include="QueryProvider.cs" />
<Compile Include="Util\TypeSystem.cs" />
+ <Compile Include="Visitors\LocalVariableExpressionReducer.cs" />
</ItemGroup>
<Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
<!-- To modify your build process, add your task inside one of the targets below and uncomment it.
Modified: trunk/nhibernate/src/NHibernate.Linq/NHibernateQueryProvider.cs
===================================================================
--- trunk/nhibernate/src/NHibernate.Linq/NHibernateQueryProvider.cs 2008-08-15 05:37:47 UTC (rev 3704)
+++ trunk/nhibernate/src/NHibernate.Linq/NHibernateQueryProvider.cs 2008-08-15 11:25:15 UTC (rev 3705)
@@ -1,17 +1,19 @@
using System;
-using System.Linq.Expressions;
+using NHibernate.Criterion;
using NHibernate.Linq.Util;
+using Expression=System.Linq.Expressions.Expression;
+using NHibernate.Linq.Visitors;
namespace NHibernate.Linq
{
public class NHibernateQueryProvider : QueryProvider
{
- private readonly ISession _session;
+ private readonly ISession session;
public NHibernateQueryProvider(ISession session)
{
- if (session == null) throw new ArgumentNullException("session");
- _session = session;
+ Guard.AgainstNull(session,"session");
+ this.session = session;
}
public override object Execute(Expression expression)
@@ -20,9 +22,9 @@
/* iteratively process expression tree here converting to NH tree */
- //expression = Evaluator.PartialEval(expression);
- //expression = new BinaryBooleanReducer().Visit(expression);
- //expression = AssociationVisitor.RewriteWithAssociations(_session.SessionFactory, expression);
+ //expression = LocalVariableExpressionReducer.Reduce(expression);
+ //expression = LogicalExpressionReducer.Reduce(expression);
+ //expression = AssociationVisitor.RewriteWithAssociations(session.SessionFactory, expression);
//expression = CollectionAliasVisitor.AssignCollectionAccessAliases(expression);
//expression = new PropertyToMethodVisitor().Visit(expression);
//expression = new BinaryExpressionOrderer().Visit(expression);
@@ -30,7 +32,7 @@
//once tree is converted to NH tree, pass it to NHibernateQueryTranslator
//which will convert the tree to an NHibernate.SqlCommand.SqlString
- //NHibernateQueryTranslator translator = new NHibernateQueryTranslator(_session);
+ //NHibernateQueryTranslator translator = new NHibernateQueryTranslator(session);
//return translator.Translate(expression,this.queryOptions);
}
}
Modified: trunk/nhibernate/src/NHibernate.Linq/Query.cs
===================================================================
--- trunk/nhibernate/src/NHibernate.Linq/Query.cs 2008-08-15 05:37:47 UTC (rev 3704)
+++ trunk/nhibernate/src/NHibernate.Linq/Query.cs 2008-08-15 11:25:15 UTC (rev 3705)
@@ -3,6 +3,7 @@
using System.Linq.Expressions;
using System.Collections;
using System.Collections.Generic;
+using NHibernate.Linq.Util;
namespace NHibernate.Linq
{
@@ -16,7 +17,7 @@
public Query(QueryProvider provider)
{
- if (provider == null) throw new ArgumentNullException("provider");
+ Guard.AgainstNull(provider,"provider");
this.provider = provider;
this.expression = Expression.Constant(this);
@@ -24,9 +25,10 @@
public Query(QueryProvider provider, Expression expression)
{
- if (provider == null) throw new ArgumentNullException("provider");
- if (expression == null) throw new ArgumentNullException("expression");
+ Guard.AgainstNull(provider,"provider");
+ Guard.AgainstNull(expression,"expression");
+
if (!typeof(IQueryable<T>).IsAssignableFrom(expression.Type))
throw new ArgumentOutOfRangeException("expression");
Added: trunk/nhibernate/src/NHibernate.Linq/Util/Guard.cs
===================================================================
--- trunk/nhibernate/src/NHibernate.Linq/Util/Guard.cs (rev 0)
+++ trunk/nhibernate/src/NHibernate.Linq/Util/Guard.cs 2008-08-15 11:25:15 UTC (rev 3705)
@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NHibernate.Linq.Util
+{
+ public static class Guard
+ {
+ public static void AgainstNull(object obj,string parameterName)
+ {
+ if (obj == null)
+ throw new ArgumentNullException(parameterName);
+ }
+ }
+}
Added: trunk/nhibernate/src/NHibernate.Linq/Visitors/LocalVariableExpressionReducer.cs
===================================================================
--- trunk/nhibernate/src/NHibernate.Linq/Visitors/LocalVariableExpressionReducer.cs (rev 0)
+++ trunk/nhibernate/src/NHibernate.Linq/Visitors/LocalVariableExpressionReducer.cs 2008-08-15 11:25:15 UTC (rev 3705)
@@ -0,0 +1,133 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Text;
+
+namespace NHibernate.Linq.Visitors
+{
+ /// <summary>
+ /// Evaluates the local references before they are translated into sql.
+ /// </summary>
+ public static class LocalVariableExpressionReducer
+ {
+ /// <summary>
+ /// Performs evaluation & replacement of independent sub-trees
+ /// </summary>
+ /// <param name="expression">The root of the expression tree.</param>
+ /// <param name="fnCanBeEvaluated">A function that decides whether a given expression node can be part of the local function.</param>
+ /// <returns>A new tree with sub-trees evaluated and replaced.</returns>
+ public static Expression Reduce(Expression expression, Func<Expression, bool> fnCanBeEvaluated)
+ {
+ return new SubtreeEvaluator(new Nominator(fnCanBeEvaluated).Nominate(expression)).Eval(expression);
+ }
+
+ /// <summary>
+ /// Performs evaluation & replacement of independent sub-trees
+ /// </summary>
+ /// <param name="expression">The root of the expression tree.</param>
+ /// <returns>A new tree with sub-trees evaluated and replaced.</returns>
+ public static Expression Reduce(Expression expression)
+ {
+ return Reduce(expression, LocalVariableExpressionReducer.CanBeEvaluatedLocally);
+ }
+
+ private static bool CanBeEvaluatedLocally(Expression expression)
+ {
+ if (expression.NodeType == ExpressionType.Constant)
+ {
+ return !(((ConstantExpression)expression).Value is IQueryable);
+ }
+
+ return expression.NodeType != ExpressionType.Parameter;
+ }
+
+ /// <summary>
+ /// Evaluates & replaces sub-trees when first candidate is reached (top-down)
+ /// </summary>
+ class SubtreeEvaluator : ExpressionVisitor
+ {
+ HashSet<Expression> candidates;
+
+ internal SubtreeEvaluator(HashSet<Expression> candidates)
+ {
+ this.candidates = candidates;
+ }
+
+ internal Expression Eval(Expression exp)
+ {
+ return this.Visit(exp);
+ }
+
+ public override Expression Visit(Expression exp)
+ {
+ if (exp == null)
+ {
+ return null;
+ }
+ if (this.candidates.Contains(exp))
+ {
+ return this.Evaluate(exp);
+ }
+ return base.Visit(exp);
+ }
+
+ private Expression Evaluate(Expression e)
+ {
+ if (e.NodeType == ExpressionType.Constant)
+ {
+ return e;
+ }
+ LambdaExpression lambda = Expression.Lambda(e);
+ Delegate fn = lambda.Compile();
+ return Expression.Constant(fn.DynamicInvoke(null), e.Type);
+ }
+ }
+
+ /// <summary>
+ /// Performs bottom-up analysis to determine which nodes can possibly
+ /// be part of an evaluated sub-tree.
+ /// </summary>
+ class Nominator : ExpressionVisitor
+ {
+ Func<Expression, bool> fnCanBeEvaluated;
+ HashSet<Expression> candidates;
+ bool cannotBeEvaluated;
+
+ internal Nominator(Func<Expression, bool> fnCanBeEvaluated)
+ {
+ this.fnCanBeEvaluated = fnCanBeEvaluated;
+ }
+
+ internal HashSet<Expression> Nominate(Expression expression)
+ {
+ this.candidates = new HashSet<Expression>();
+ this.Visit(expression);
+ return this.candidates;
+ }
+
+ public override Expression Visit(Expression expression)
+ {
+ if (expression != null)
+ {
+ bool saveCannotBeEvaluated = this.cannotBeEvaluated;
+ this.cannotBeEvaluated = false;
+ base.Visit(expression);
+ if (!this.cannotBeEvaluated)
+ {
+ if (this.fnCanBeEvaluated(expression))
+ {
+ this.candidates.Add(expression);
+ }
+ else
+ {
+ this.cannotBeEvaluated = true;
+ }
+ }
+ this.cannotBeEvaluated |= saveCannotBeEvaluated;
+ }
+ return expression;
+ }
+ }
+ }
+}
Modified: trunk/nhibernate/src/NHibernate.Linq/Visitors/LogicalExpressionReducer.cs
===================================================================
--- trunk/nhibernate/src/NHibernate.Linq/Visitors/LogicalExpressionReducer.cs 2008-08-15 05:37:47 UTC (rev 3704)
+++ trunk/nhibernate/src/NHibernate.Linq/Visitors/LogicalExpressionReducer.cs 2008-08-15 11:25:15 UTC (rev 3705)
@@ -12,9 +12,14 @@
/// </summary>
//May be used for animal.Offspring.Any() == true
- //Eventhough it is almost unnecessary to reduce not(not(true)) kind of expression, but simplified expressions are gold.
+ //Eventhough it is almost unnecessary to reduce not(not(true)) kind of expression(sql servers can easily optimize them,
+ //simplified expressions is gold for debugging.
public class LogicalExpressionReducer:ExpressionVisitor
{
+ public static Expression Reduce(Expression expr)
+ {
+ return new LogicalExpressionReducer().Visit(expr);
+ }
protected override Expression VisitBinary(BinaryExpression expr)
{
bool modified;
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