[Nhibernate-commit] SF.net SVN: nhibernate:[5864] trunk/nhibernate/src/NHibernate

[<fab...@us...>]

Revision: 5864
          http://nhibernate.svn.sourceforge.net/nhibernate/?rev=5864&view=rev
Author:   fabiomaulo
Date:     2011-05-23 19:10:23 +0000 (Mon, 23 May 2011)

Log Message:
-----------
Fix NH-2317

Modified Paths:
--------------
    trunk/nhibernate/src/NHibernate/Linq/ReWriters/QueryReferenceExpressionFlattener.cs
    trunk/nhibernate/src/NHibernate.Test/NHSpecificTest/NH2317/Fixture.cs

Modified: trunk/nhibernate/src/NHibernate/Linq/ReWriters/QueryReferenceExpressionFlattener.cs
===================================================================
--- trunk/nhibernate/src/NHibernate/Linq/ReWriters/QueryReferenceExpressionFlattener.cs	2011-05-23 19:07:03 UTC (rev 5863)
+++ trunk/nhibernate/src/NHibernate/Linq/ReWriters/QueryReferenceExpressionFlattener.cs	2011-05-23 19:10:23 UTC (rev 5864)
@@ -1,61 +1,82 @@
-using System.Linq.Expressions;
+using System.Collections.Generic;
+using System.Linq;
+using System.Linq.Expressions;
 using NHibernate.Linq.Visitors;
 using Remotion.Linq;
 using Remotion.Linq.Clauses;
 using Remotion.Linq.Clauses.Expressions;
+using Remotion.Linq.Clauses.ResultOperators;
 
 namespace NHibernate.Linq.ReWriters
 {
+	/// <summary>
+	/// This re-writer is responsible to re-write a query without a body (no where-clause and so on).
+	/// </summary>
 	public class QueryReferenceExpressionFlattener : NhExpressionTreeVisitor
 	{
-	    private readonly QueryModel _model;
+		private readonly QueryModel _model;
+		// NOTE: Skip/Take are not completelly flattenable since Take(10).Skip(5).Take(2) should result in a subqueries-tsunami (so far not common understanding from our users)
+		private static readonly List<System.Type> FlattenableResultOperactors = new List<System.Type>
+		                                                                        {
+		                                                                        	typeof(CacheableResultOperator),
+																																							typeof(SkipResultOperator),
+																																							typeof(TakeResultOperator),
+																																						};
 
-	    private QueryReferenceExpressionFlattener(QueryModel model)
+		private QueryReferenceExpressionFlattener(QueryModel model)
 		{
-		    _model = model;
+			_model = model;
 		}
 
-	    public static void ReWrite(QueryModel model)
+		public static void ReWrite(QueryModel model)
 		{
 			var visitor = new QueryReferenceExpressionFlattener(model);
 			model.TransformExpressions(visitor.VisitExpression);
 		}
 
-        protected override Expression VisitSubQueryExpression(SubQueryExpression subQuery)
-        {
-            if ((subQuery.QueryModel.BodyClauses.Count == 0) &&
-                ((subQuery.QueryModel.ResultOperators.Count == 0) || (subQuery.QueryModel.ResultOperators.Count == 1 && subQuery.QueryModel.ResultOperators[0] is CacheableResultOperator))
-                )
-            {
-                var selectQuerySource =
-                    subQuery.QueryModel.SelectClause.Selector as QuerySourceReferenceExpression;
+		protected override Expression VisitSubQueryExpression(SubQueryExpression subQuery)
+		{
+			var hasBodyClauses = subQuery.QueryModel.BodyClauses.Count > 0;
+			if(hasBodyClauses)
+			{
+				return base.VisitSubQueryExpression(subQuery);
+			}
+			var resultOperators = subQuery.QueryModel.ResultOperators;
+			if (resultOperators.Count == 0 || HasJustAllFlattenableOperator(resultOperators))
+			{
+				var selectQuerySource = subQuery.QueryModel.SelectClause.Selector as QuerySourceReferenceExpression;
 
-                if (selectQuerySource != null && selectQuerySource.ReferencedQuerySource == subQuery.QueryModel.MainFromClause)
-                {
-                    if (subQuery.QueryModel.ResultOperators.Count == 1)
-                    {
-                        _model.ResultOperators.Add(subQuery.QueryModel.ResultOperators[0]);
-                    }
+				if (selectQuerySource != null && selectQuerySource.ReferencedQuerySource == subQuery.QueryModel.MainFromClause)
+				{
+					foreach (var resultOperator in resultOperators)
+					{
+						_model.ResultOperators.Add(resultOperator);
+					}
 
-                    return subQuery.QueryModel.MainFromClause.FromExpression;
-                }
-            }
+					return subQuery.QueryModel.MainFromClause.FromExpression;
+				}
+			}
 
-            return base.VisitSubQueryExpression(subQuery);
-        }
+			return base.VisitSubQueryExpression(subQuery);
+		}
 
-        protected override Expression VisitQuerySourceReferenceExpression(QuerySourceReferenceExpression expression)
+		private bool HasJustAllFlattenableOperator(IEnumerable<ResultOperatorBase> resultOperators)
 		{
+			return resultOperators.All(x => FlattenableResultOperactors.Contains(x.GetType()));
+		}
+
+		protected override Expression VisitQuerySourceReferenceExpression(QuerySourceReferenceExpression expression)
+		{
 			var fromClauseBase = expression.ReferencedQuerySource as FromClauseBase;
 
-			if (fromClauseBase != null && 
+			if (fromClauseBase != null &&
 			    fromClauseBase.FromExpression is QuerySourceReferenceExpression &&
 			    expression.Type == fromClauseBase.FromExpression.Type)
 			{
 				return fromClauseBase.FromExpression;
 			}
 
-		    return base.VisitQuerySourceReferenceExpression(expression);
+			return base.VisitQuerySourceReferenceExpression(expression);
 		}
 	}
 }
\ No newline at end of file

Modified: trunk/nhibernate/src/NHibernate.Test/NHSpecificTest/NH2317/Fixture.cs
===================================================================
--- trunk/nhibernate/src/NHibernate.Test/NHSpecificTest/NH2317/Fixture.cs	2011-05-23 19:07:03 UTC (rev 5863)
+++ trunk/nhibernate/src/NHibernate.Test/NHSpecificTest/NH2317/Fixture.cs	2011-05-23 19:10:23 UTC (rev 5864)
@@ -5,7 +5,7 @@
 
 namespace NHibernate.Test.NHSpecificTest.NH2317
 {
-	[TestFixture, Ignore("Not fixed yet.")]
+	[TestFixture]
 	public class Fixture : BugTestCase
 	{
 		protected override void OnSetUp()
@@ -28,8 +28,12 @@
 			using (var session = sessions.OpenSession())
 			using(session.BeginTransaction())
 			{
-				// HQL show how should look the HQL tree in this case and in all others casses where Skip/Take are not the last sentences
-				var expected = session.CreateQuery("select a.id from Artist a where a in (from Artist take 3)").List<int>();
+				// The HQL : "select a.id from Artist a where a in (from Artist take 3)"
+				// shows how should look the HQL tree in the case where Skip/Take are not the last sentences.
+
+				// When the query has no where-clauses the the HQL can be reduced to: "select a.id from Artist a take 3)"
+
+				var expected = session.CreateQuery("select a.id from Artist a take 3").List<int>();
 				var actual = session.Query<Artist>().Take(3).Select(a => a.Id).ToArray();
 				actual.Should().Have.SameValuesAs(expected);
 			}


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