NH-2285: Support for LockMode in linq provider

Author: OnurGumus

src/NHibernate.Test/Linq/QueryLock.cs

@@ -0,0 +1,47 @@
+using System.Linq;
+using NHibernate.AdoNet;
+using NHibernate.Cfg;
+using NHibernate.Engine;
+using NHibernate.Linq;
+using NUnit.Framework;
+
+namespace NHibernate.Test.Linq
+{
+	public class QueryLock : LinqTestCase
+	{
+
+		[Test]
+		public void CanSetLockLinqQueries()
+		{
+			var result = (from e in db.Customers
+						  where e.CompanyName == "Corp"
+						  select e).SetLockMode(LockMode.Upgrade).ToList();
+
+		}
+
+
+		[Test]
+		public void CanSetLockOnLinqPagingQuery()
+		{
+			var result = (from e in db.Customers
+						  where e.CompanyName == "Corp"
+						  select e).Skip(5).Take(5).SetLockMode(LockMode.Upgrade).ToList();
+		}
+
+
+		[Test]
+		public void CanLockBeforeSkipOnLinqOrderedPageQuery()
+		{
+			var result = (from e in db.Customers
+						  orderby e.CompanyName
+						  select e)
+				.SetLockMode(LockMode.Upgrade).Skip(5).Take(5).ToList();
+
+
+		}
+
+
+	}
+
+}
+

src/NHibernate.Test/NHibernate.Test.csproj

@@ -543,6 +543,7 @@
     <Compile Include="Linq\DateTimeTests.cs" />
     <Compile Include="Linq\ExpressionSessionLeakTest.cs" />
     <Compile Include="Linq\LoggingTests.cs" />
+    <Compile Include="Linq\QueryLock.cs" />
     <Compile Include="Linq\QueryTimeoutTests.cs" />
     <Compile Include="Linq\JoinTests.cs" />
     <Compile Include="Linq\CustomExtensionsExample.cs" />

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 (LockResultOperator),
 			};
 
 		public static void ReWrite(QueryModel queryModel)
@@ -60,8 +61,8 @@ public static void ReWrite(QueryModel queryModel)
 					{
 						FlattenSubQuery(queryModel, subQueryExpression.QueryModel, groupBy);
 						RemoveCostantGroupByKeys(queryModel, groupBy);
-					}
-				}
+			}
+		}
 			}
 		}
 
@@ -112,7 +113,7 @@ private static void RemoveCostantGroupByKeys(QueryModel queryModel, GroupResultO
 			{
 				// Remove the Group By clause completely if all the keys are constant (redundant)
 				queryModel.ResultOperators.Remove(groupBy);
-			}
+	}
 			else
 			{
 				// Re-write the KeySelector as an object array of the non-constant keys

src/NHibernate/Linq/LinqExtensionMethods.cs

@@ -40,6 +40,16 @@ public static IQueryable<T> Cacheable<T>(this IQueryable<T> query)
 			return new NhQueryable<T>(query.Provider, callExpression);
 		}
 
+		public static IQueryable<T> SetLockMode<T>(this IQueryable<T> query, LockMode lockMode)
+		{
+			var method = ReflectionHelper.GetMethodDefinition(() => SetLockMode<object>(null, LockMode.Read)).MakeGenericMethod(typeof(T));
+
+			var callExpression = Expression.Call(method, query.Expression, Expression.Constant(lockMode));
+
+			return new NhQueryable<T>(query.Provider, callExpression);
+		}
+
+
 		public static IQueryable<T> CacheMode<T>(this IQueryable<T> query, CacheMode cacheMode)
 		{
 			var method = ReflectionHelper.GetMethodDefinition(() => CacheMode<object>(null, NHibernate.CacheMode.Normal)).MakeGenericMethod(typeof(T));

src/NHibernate/Linq/NhRelinqQueryParser.cs

@@ -78,6 +78,14 @@ public NHibernateNodeTypeProvider()
 					}, typeof (TimeoutExpressionNode)
 				);
 
+			methodInfoRegistry.Register(
+				new[]
+					{
+						ReflectionHelper.GetMethodDefinition(() => LinqExtensionMethods.SetLockMode<object>(null, LockMode.Read)),
+					}, typeof(LockExpressionNode)
+				);
+
+
 			var nodeTypeProvider = ExpressionTreeParser.CreateDefaultNodeTypeProvider();
 			nodeTypeProvider.InnerProviders.Add(methodInfoRegistry);
 			defaultNodeTypeProvider = nodeTypeProvider;
@@ -137,6 +145,30 @@ protected override ResultOperatorBase CreateResultOperator(ClauseGenerationConte
 		}
 	}
 
+	internal class LockExpressionNode : ResultOperatorExpressionNodeBase
+	{
+		private readonly MethodCallExpressionParseInfo _parseInfo;
+		private readonly ConstantExpression _lockMode;
+
+		public LockExpressionNode(MethodCallExpressionParseInfo parseInfo, ConstantExpression lockMode)
+			: base(parseInfo, null, null)
+		{
+			_parseInfo = parseInfo;
+			_lockMode = lockMode;
+		}
+
+		public override Expression Resolve(ParameterExpression inputParameter, Expression expressionToBeResolved, ClauseGenerationContext clauseGenerationContext)
+		{
+			return Source.Resolve(inputParameter, expressionToBeResolved, clauseGenerationContext);
+		}
+
+		protected override ResultOperatorBase CreateResultOperator(ClauseGenerationContext clauseGenerationContext)
+		{
+			return new LockResultOperator(_parseInfo, _lockMode);
+		}
+	}
+
+
 	public class CacheableResultOperator : ResultOperatorBase
 	{
 		public MethodCallExpressionParseInfo ParseInfo { get; private set; }
@@ -222,4 +254,35 @@ public override void TransformExpressions(Func<Expression, Expression> transform
 		{
 		}
 	}
-}
+	internal class LockResultOperator : ResultOperatorBase
+	{
+		public MethodCallExpressionParseInfo ParseInfo { get; private set; }
+		public ConstantExpression LockMode { get; private set; }
+
+		public LockResultOperator(MethodCallExpressionParseInfo parseInfo, ConstantExpression lockMode)
+		{
+			ParseInfo = parseInfo;
+			LockMode = lockMode;
+		}
+
+		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)
+		{
+		}
+	}
+
+}

src/NHibernate/Linq/ReWriters/ResultOperatorRewriter.cs

@@ -67,6 +67,7 @@ private class ResultOperatorExpressionRewriter : ExpressionTreeVisitor
 					typeof(OfTypeResultOperator),
 					typeof(CacheableResultOperator),
 					typeof(TimeoutResultOperator),
+					typeof (LockResultOperator),
 					typeof(CastResultOperator), // see ProcessCast class
 				};
 

src/NHibernate/Linq/Visitors/QueryModelVisitor.cs

@@ -124,6 +124,7 @@ static QueryModelVisitor()
 			ResultOperatorMap.Add<FetchManyRequest, ProcessFetchMany>();
 			ResultOperatorMap.Add<CacheableResultOperator, ProcessCacheable>();
 			ResultOperatorMap.Add<TimeoutResultOperator, ProcessTimeout>();
+			ResultOperatorMap.Add<LockResultOperator, ProcessLock>();
 			ResultOperatorMap.Add<OfTypeResultOperator, ProcessOfType>();
 			ResultOperatorMap.Add<CastResultOperator, ProcessCast>();
 		}

src/NHibernate/Linq/Visitors/ResultOperatorProcessors/ProcessLock.cs

@@ -0,0 +1,12 @@
+
+namespace NHibernate.Linq.Visitors.ResultOperatorProcessors
+{
+	internal class ProcessLock : IResultOperatorProcessor<LockResultOperator>
+	{
+		public void Process(LockResultOperator resultOperator, QueryModelVisitor queryModelVisitor, IntermediateHqlTree tree)
+		{
+			tree.AddAdditionalCriteria((q, p) => q.SetLockMode(queryModelVisitor.Model.MainFromClause.ItemName, (LockMode)resultOperator.LockMode.Value));
+		}
+	}
+}
+

src/NHibernate/NHibernate.csproj

@@ -331,6 +331,7 @@
     <Compile Include="Linq\Visitors\QueryExpressionSourceIdentifer.cs" />
     <Compile Include="Linq\Visitors\QuerySourceIdentifier.cs" />
     <Compile Include="Linq\Visitors\MemberExpressionJoinDetector.cs" />
+    <Compile Include="Linq\Visitors\ResultOperatorProcessors\ProcessLock.cs" />
     <Compile Include="Linq\Visitors\ResultOperatorProcessors\ProcessTimeout.cs" />
     <Compile Include="Linq\Visitors\ResultOperatorProcessors\ProcessAggregateFromSeed.cs" />
     <Compile Include="Linq\NestedSelects\NestedSelectRewriter.cs" />