NH-3820 - Basic support for query hints.

build-common/common.xml

@@ -52,7 +52,7 @@
 		effectively SP0).
 	-->
 
-	<property name="project.version" value="4.1.1.GA" overwrite="false" />
+	<property name="project.version" value="4.1.1.SP1" overwrite="false" />
 
 	<!-- This version number should be changed if, but only if, there are incompatible
 	     changes compared to the previous version. -->

src/NHibernate/Dialect/Dialect.cs

@@ -1399,15 +1399,29 @@ public IList<SqlString> GetTokens()
 			}
 		}
 
-		#endregion
+        #endregion
 
-		#region Limit/offset support
+        #region Query Hint support
 
-		/// <summary>
-		/// Does this Dialect have some kind of <c>LIMIT</c> syntax?
-		/// </summary>
-		/// <value>False, unless overridden.</value>
-		public virtual bool SupportsLimit
+	    public virtual bool SupportsOption
+	    {
+	        get { return false; }
+	    }
+
+        public virtual SqlString GetOptionString(SqlString queryString, string option)
+        {
+            throw new NotSupportedException("Dialect does not have support for query hints.");
+        }
+
+        #endregion
+
+        #region Limit/offset support
+
+        /// <summary>
+        /// Does this Dialect have some kind of <c>LIMIT</c> syntax?
+        /// </summary>
+        /// <value>False, unless overridden.</value>
+        public virtual bool SupportsLimit
 		{
 			get { return false; }
 		}

src/NHibernate/Dialect/MsSql2008Dialect.cs

@@ -2,6 +2,7 @@
 using NHibernate.Cfg;
 using NHibernate.Dialect.Function;
 using NHibernate.Driver;
+using NHibernate.SqlCommand;
 
 namespace NHibernate.Dialect
 {
@@ -38,5 +39,15 @@ protected override void RegisterDefaultProperties()
 			base.RegisterDefaultProperties();
 			DefaultProperties[Environment.ConnectionDriver] = typeof(Sql2008ClientDriver).AssemblyQualifiedName;
 		}
-	}
+
+        public override bool SupportsOption
+        {
+            get { return false; }
+        }
+
+        public override SqlString GetOptionString(SqlString queryString, string option)
+        {
+            return queryString.Append($" OPTION({option})");
+        }
+    }
 }

src/NHibernate/Engine/Query/HQLQueryPlan.cs

@@ -100,6 +100,7 @@ public void PerformList(QueryParameters queryParameters, ISessionImplementor ses
 				RowSelection selection = new RowSelection();
 				selection.FetchSize = queryParameters.RowSelection.FetchSize;
 				selection.Timeout = queryParameters.RowSelection.Timeout;
+			    selection.Option = queryParameters.RowSelection.Option;
 				queryParametersToUse = queryParameters.CreateCopyUsing(selection);
 			}
 			else

src/NHibernate/Engine/RowSelection.cs

@@ -18,6 +18,7 @@ public sealed class RowSelection
 		private int maxRows = NoValue;
 		private int timeout = NoValue;
 		private int fetchSize = NoValue;
+	    private string option = null;
 
 		/// <summary>
 		/// Gets or Sets the Index of the First Row to Select
@@ -62,5 +63,11 @@ public bool DefinesLimits
 		{
 			get { return maxRows != NoValue || firstRow > 0; }
 		}
+
+	    public string Option
+	    {
+	        get { return option; }
+            set { option = value; }
+	    }
 	}
 }

src/NHibernate/IQuery.cs

@@ -216,6 +216,12 @@ public interface IQuery
 		/// <param name="timeout"></param>
 		IQuery SetTimeout(int timeout);
 
+        /// <summary>
+        /// The query hint options specified for the query.
+        /// </summary>
+        /// <param name="option">The specified option</param>
+	    IQuery SetOption(string option);
+
 		/// <summary> Set a fetch size for the underlying ADO query.</summary>
 		/// <param name="fetchSize">the fetch size </param>
 		IQuery SetFetchSize(int fetchSize);

src/NHibernate/Impl/AbstractDetachedQuery.cs

@@ -425,7 +425,8 @@ protected void SetQueryProperties(IQuery q)
 				.SetReadOnly(readOnly)
 				.SetTimeout(selection.Timeout)
 				.SetFlushMode(flushMode)
-				.SetFetchSize(selection.FetchSize);
+				.SetFetchSize(selection.FetchSize)
+                .SetOption(selection.Option);
 			if (!string.IsNullOrEmpty(comment))
 				q.SetComment(comment);
 			if (!string.IsNullOrEmpty(cacheRegion))

src/NHibernate/Impl/AbstractQueryImpl.cs

@@ -785,6 +785,12 @@ public IQuery SetTimeout(int timeout)
 			return this;
 		}
 
+	    public IQuery SetOption(string option)
+	    {
+	        selection.Option = option;
+            return this;
+	    }
+
 		public IQuery SetFetchSize(int fetchSize)
 		{
 			selection.FetchSize = fetchSize;

src/NHibernate/Linq/GroupBy/AggregatingGroupByRewriter.cs

@@ -40,7 +40,8 @@ public static class AggregatingGroupByRewriter
 				typeof (AnyResultOperator),
 				typeof (AllResultOperator),
 				typeof (TimeoutResultOperator),
-				typeof (CacheableResultOperator)
+				typeof (CacheableResultOperator),
+                typeof (OptionResultOperator),
 			};
 
 		public static void ReWrite(QueryModel queryModel)

src/NHibernate/Linq/LinqExtensionMethods.cs

@@ -67,7 +67,16 @@ public static IQueryable<T> Timeout<T>(this IQueryable<T> query, int timeout)
 			return new NhQueryable<T>(query.Provider, callExpression);
 		}
 
-		public static IEnumerable<T> ToFuture<T>(this IQueryable<T> query)
+        public static IQueryable<T> WithOption<T>(this IQueryable<T> query, string option)
+        {
+            var method = ReflectionHelper.GetMethodDefinition(() => WithOption<object>(null, null)).MakeGenericMethod(typeof(T));
+
+            var callExpression = Expression.Call(method, query.Expression, Expression.Constant(option));
+
+            return new NhQueryable<T>(query.Provider, callExpression);
+        }
+
+        public static IEnumerable<T> ToFuture<T>(this IQueryable<T> query)
 		{
 			var nhQueryable = query as QueryableBase<T>;
 			if (nhQueryable == null)

src/NHibernate/Linq/NhRelinqQueryParser.cs

@@ -78,7 +78,14 @@ public NHibernateNodeTypeProvider()
 					}, typeof (TimeoutExpressionNode)
 				);
 
-			var nodeTypeProvider = ExpressionTreeParser.CreateDefaultNodeTypeProvider();
+            methodInfoRegistry.Register(
+                new[]
+                    {
+                        ReflectionHelper.GetMethodDefinition(() => LinqExtensionMethods.WithOption<object>(null, null)),
+                    }, typeof(OptionExpressionNode)
+                );
+
+            var nodeTypeProvider = ExpressionTreeParser.CreateDefaultNodeTypeProvider();
 			nodeTypeProvider.InnerProviders.Add(methodInfoRegistry);
 			defaultNodeTypeProvider = nodeTypeProvider;
 		}
@@ -168,8 +175,30 @@ public override void TransformExpressions(Func<Expression, Expression> transform
 		}
 	}
 
-
-	internal class TimeoutExpressionNode : ResultOperatorExpressionNodeBase
+    internal class OptionExpressionNode : ResultOperatorExpressionNodeBase
+    {
+        private readonly MethodCallExpressionParseInfo _parseInfo;
+        private readonly ConstantExpression _option;
+
+        public OptionExpressionNode(MethodCallExpressionParseInfo parseInfo, ConstantExpression option)
+            : base(parseInfo, null, null)
+        {
+            _parseInfo = parseInfo;
+            _option = option;
+        }
+
+        public override Expression Resolve(ParameterExpression inputParameter, Expression expressionToBeResolved, ClauseGenerationContext clauseGenerationContext)
+        {
+            return Source.Resolve(inputParameter, expressionToBeResolved, clauseGenerationContext);
+        }
+
+        protected override ResultOperatorBase CreateResultOperator(ClauseGenerationContext clauseGenerationContext)
+        {
+            return new OptionResultOperator(_parseInfo, _option);
+        }
+    }
+
+    internal class TimeoutExpressionNode : ResultOperatorExpressionNodeBase
 	{
 		private readonly MethodCallExpressionParseInfo _parseInfo;
 		private readonly ConstantExpression _timeout;
@@ -189,10 +218,41 @@ public override Expression Resolve(ParameterExpression inputParameter, Expressio
 		protected override ResultOperatorBase CreateResultOperator(ClauseGenerationContext clauseGenerationContext)
 		{
 			return new TimeoutResultOperator(_parseInfo, _timeout);
-		}
-	}
-
-	internal class TimeoutResultOperator : ResultOperatorBase
+        }
+    }
+
+    internal class OptionResultOperator : ResultOperatorBase
+    {
+        public MethodCallExpressionParseInfo ParseInfo { get; private set; }
+        public ConstantExpression Option { get; private set; }
+
+        public OptionResultOperator(MethodCallExpressionParseInfo parseInfo, ConstantExpression timeout)
+        {
+            ParseInfo = parseInfo;
+            Option = timeout;
+        }
+
+        public override IStreamedData ExecuteInMemory(IStreamedData input)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override IStreamedDataInfo GetOutputDataInfo(IStreamedDataInfo inputInfo)
+        {
+            return inputInfo;
+        }
+
+        public override ResultOperatorBase Clone(CloneContext cloneContext)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override void TransformExpressions(Func<Expression, Expression> transformation)
+        {
+        }
+    }
+
+    internal class TimeoutResultOperator : ResultOperatorBase
 	{
 		public MethodCallExpressionParseInfo ParseInfo { get; private set; }
 		public ConstantExpression Timeout { get; private set; }

src/NHibernate/Linq/ReWriters/QueryReferenceExpressionFlattener.cs

@@ -18,7 +18,8 @@ public class QueryReferenceExpressionFlattener : ExpressionTreeVisitor
 			typeof (CacheableResultOperator),
 			typeof (TimeoutResultOperator),
 			typeof (FetchOneRequest),
-			typeof (FetchManyRequest)
+			typeof (FetchManyRequest),
+            typeof (OptionResultOperator)
 		};
 
 		private QueryReferenceExpressionFlattener(QueryModel model)

src/NHibernate/Linq/ReWriters/ResultOperatorRewriter.cs

@@ -68,6 +68,7 @@ private class ResultOperatorExpressionRewriter : ExpressionTreeVisitor
 					typeof(CacheableResultOperator),
 					typeof(TimeoutResultOperator),
 					typeof(CastResultOperator), // see ProcessCast class
+                    typeof(OptionResultOperator),
 				};
 
 			private readonly List<ResultOperatorBase> resultOperators = new List<ResultOperatorBase>();

src/NHibernate/Linq/Visitors/QueryModelVisitor.cs

@@ -126,7 +126,8 @@ static QueryModelVisitor()
 			ResultOperatorMap.Add<TimeoutResultOperator, ProcessTimeout>();
 			ResultOperatorMap.Add<OfTypeResultOperator, ProcessOfType>();
 			ResultOperatorMap.Add<CastResultOperator, ProcessCast>();
-		}
+            ResultOperatorMap.Add<OptionResultOperator, ProcessOption>();
+        }
 
 		private QueryModelVisitor(VisitorParameters visitorParameters, bool root, QueryModel queryModel)
 		{

src/NHibernate/Loader/Hql/QueryLoader.cs

@@ -59,7 +59,15 @@ public override bool IsSubselectLoadingEnabled
 			get { return HasSubselectLoadableCollections(); }
 		}
 
-		protected override SqlString ApplyLocks(SqlString sql, IDictionary<string, LockMode> lockModes,
+	    protected override SqlString ApplyOptions(SqlString sql, string option, Dialect.Dialect dialect)
+	    {
+	        if (!dialect.SupportsOption && String.IsNullOrEmpty(option))
+	            return sql;
+
+	        return dialect.GetOptionString(sql, option);
+	    }
+
+        protected override SqlString ApplyLocks(SqlString sql, IDictionary<string, LockMode> lockModes,
 												Dialect.Dialect dialect)
 		{
 			if (lockModes == null || lockModes.Count == 0)

src/NHibernate/Loader/Loader.cs

@@ -177,6 +177,11 @@ protected virtual SqlString ApplyLocks(SqlString sql, IDictionary<string, LockMo
 			return sql;
 		}
 
+	    protected virtual SqlString ApplyOptions(SqlString sql, string option, Dialect.Dialect dialect)
+	    {
+	        return sql;
+	    }
+
 		/// <summary>
 		/// Does this query return objects that might be already cached by 
 		/// the session, whose lock mode may need upgrading.
@@ -205,6 +210,11 @@ protected virtual SqlString PreprocessSQL(SqlString sql, QueryParameters paramet
 		{
 			sql = ApplyLocks(sql, parameters.LockModes, dialect);
 
+            RowSelection selection = parameters.RowSelection;
+		    if (selection != null && !String.IsNullOrEmpty(selection.Option))
+		        sql = ApplyOptions(sql, selection.Option, dialect);
+
+
 			return Factory.Settings.IsCommentsEnabled ? PrependComment(sql, parameters) : sql;
 		}
 

src/NHibernate/NHibernate.csproj

@@ -141,6 +141,7 @@
     <Compile Include="Connection\DriverConnectionProvider.cs" />
     <Compile Include="Connection\IConnectionProvider.cs" />
     <Compile Include="Connection\UserSuppliedConnectionProvider.cs" />
+    <Compile Include="Linq\Visitors\ResultOperatorProcessors\ProcessOption.cs" />
     <Compile Include="Util\DelegateHelper.cs" />
     <Compile Include="Dialect\BitwiseFunctionOperation.cs" />
     <Compile Include="Dialect\DB2Dialect.cs" />