/// <summary>
/// This API supports the Entity Framework Core infrastructure and is not intended to be used
/// directly from your code. This API may change or be removed in future releases.
/// </summary>
public virtual Expression HandleResultOperator(
EntityQueryModelVisitor entityQueryModelVisitor,
ResultOperatorBase resultOperator,
QueryModel queryModel)
{
var relationalQueryModelVisitor
= (RelationalQueryModelVisitor)entityQueryModelVisitor;
var selectExpression
= relationalQueryModelVisitor
.TryGetQuery(queryModel.MainFromClause);
var handlerContext
= new HandlerContext(
_resultOperatorHandler,
_model,
_sqlTranslatingExpressionVisitorFactory,
_selectExpressionFactory,
relationalQueryModelVisitor,
resultOperator,
queryModel,
selectExpression);
Func <HandlerContext, Expression> resultHandler;
if (relationalQueryModelVisitor.RequiresClientEval ||
relationalQueryModelVisitor.RequiresClientSelectMany ||
relationalQueryModelVisitor.RequiresClientJoin ||
relationalQueryModelVisitor.RequiresClientFilter ||
relationalQueryModelVisitor.RequiresClientOrderBy ||
relationalQueryModelVisitor.RequiresClientResultOperator ||
!_resultHandlers.TryGetValue(resultOperator.GetType(), out resultHandler) ||
selectExpression == null)
{
return(handlerContext.EvalOnClient());
}
if (relationalQueryModelVisitor.RequiresClientSingleColumnResultOperator &&
!(resultOperator is SkipResultOperator ||
resultOperator is TakeResultOperator ||
resultOperator is FirstResultOperator ||
resultOperator is SingleResultOperator ||
resultOperator is CountResultOperator ||
resultOperator is AllResultOperator ||
resultOperator is AnyResultOperator ||
resultOperator is GroupResultOperator))
{
return(handlerContext.EvalOnClient());
}
return(resultHandler(handlerContext));
}
private static Expression HandleLast(HandlerContext handlerContext)
{
var requiresClientResultOperator = true;
if (handlerContext.SelectExpression.OrderBy.Any())
{
foreach (var ordering in handlerContext.SelectExpression.OrderBy)
{
ordering.OrderingDirection
= ordering.OrderingDirection == OrderingDirection.Asc
? OrderingDirection.Desc
: OrderingDirection.Asc;
}
handlerContext.SelectExpression.Limit = Expression.Constant(1);
requiresClientResultOperator = false;
}
requiresClientResultOperator
= requiresClientResultOperator ||
(!((LastResultOperator)handlerContext.ResultOperator).ReturnDefaultWhenEmpty &&
handlerContext.QueryModelVisitor.ParentQueryModelVisitor != null);
return(handlerContext.EvalOnClient(requiresClientResultOperator: requiresClientResultOperator));
}
private static Expression HandleDistinct(HandlerContext handlerContext)
{
if (!handlerContext.QueryModelVisitor.RequiresClientProjection)
{
var selectExpression = handlerContext.SelectExpression;
selectExpression.IsDistinct = true;
if (selectExpression.OrderBy.Any(o =>
{
var orderByColumnExpression = o.Expression.TryGetColumnExpression();
if (orderByColumnExpression == null)
{
return(true);
}
return(!selectExpression.Projection.Any(e =>
{
var projectionColumnExpression = e.TryGetColumnExpression();
return projectionColumnExpression != null &&
projectionColumnExpression.Equals(orderByColumnExpression);
}));
}))
{
handlerContext.SelectExpression.ClearOrderBy();
}
return(handlerContext.EvalOnServer);
}
return(handlerContext.EvalOnClient());
}
private static Expression HandleAverage(HandlerContext handlerContext)
{
if (!handlerContext.QueryModelVisitor.RequiresClientProjection &&
handlerContext.SelectExpression.Projection.Count == 1)
{
var expression = handlerContext.SelectExpression.Projection.First();
if (!(expression.RemoveConvert() is SelectExpression))
{
var inputType = expression.Type;
var outputType = expression.Type;
var nonNullableInputType = inputType.UnwrapNullableType();
if (nonNullableInputType == typeof(int) ||
nonNullableInputType == typeof(long))
{
outputType = inputType.IsNullableType() ? typeof(double?) : typeof(double);
}
expression = new ExplicitCastExpression(expression, outputType);
var averageExpression = new SqlFunctionExpression("AVG", expression.Type, new [] { expression });
handlerContext.SelectExpression.SetProjectionExpression(averageExpression);
return((Expression)_transformClientExpressionMethodInfo
.MakeGenericMethod(averageExpression.Type)
.Invoke(null, new object [] { handlerContext }));
}
}
return(handlerContext.EvalOnClient());
}
/// <summary>
/// This API supports the Entity Framework Core infrastructure and is not intended to be used
/// directly from your code. This API may change or be removed in future releases.
/// </summary>
public virtual Expression HandleResultOperator(
EntityQueryModelVisitor entityQueryModelVisitor,
ResultOperatorBase resultOperator,
QueryModel queryModel)
{
var relationalQueryModelVisitor
= (RelationalQueryModelVisitor)entityQueryModelVisitor;
var selectExpression
= relationalQueryModelVisitor
.TryGetQuery(queryModel.MainFromClause);
var handlerContext
= new HandlerContext(
_resultOperatorHandler,
_model,
_sqlTranslatingExpressionVisitorFactory,
_selectExpressionFactory,
relationalQueryModelVisitor,
resultOperator,
queryModel,
selectExpression);
return(relationalQueryModelVisitor.RequiresClientEval ||
relationalQueryModelVisitor.RequiresClientSelectMany ||
relationalQueryModelVisitor.RequiresClientJoin ||
relationalQueryModelVisitor.RequiresClientFilter ||
relationalQueryModelVisitor.RequiresClientOrderBy ||
relationalQueryModelVisitor.RequiresClientResultOperator ||
relationalQueryModelVisitor.RequiresStreamingGroupResultOperator ||
!_resultHandlers.TryGetValue(resultOperator.GetType(), out var resultHandler) ||
selectExpression == null
? handlerContext.EvalOnClient()
: resultHandler(handlerContext));
}
private static Expression HandleAll(HandlerContext handlerContext)
{
var sqlTranslatingVisitor
= handlerContext.CreateSqlTranslatingVisitor();
PrepareSelectExpressionForAggregate(handlerContext.SelectExpression);
var predicate
= sqlTranslatingVisitor.Visit(
((AllResultOperator)handlerContext.ResultOperator).Predicate);
if (predicate != null)
{
var innerSelectExpression = handlerContext.SelectExpression.Clone();
innerSelectExpression.ClearProjection();
innerSelectExpression.AddToProjection(Expression.Constant(1));
innerSelectExpression.AddToPredicate(Expression.Not(predicate));
if (innerSelectExpression.Limit == null &&
innerSelectExpression.Offset == null)
{
innerSelectExpression.ClearOrderBy();
}
SetConditionAsProjection(
handlerContext,
Expression.Not(new ExistsExpression(innerSelectExpression)));
return(TransformClientExpression <bool>(handlerContext));
}
return(handlerContext.EvalOnClient());
}
private static Expression HandleFirst(HandlerContext handlerContext)
{
handlerContext.SelectExpression.Limit = Expression.Constant(1);
var requiresClientResultOperator = !((FirstResultOperator)handlerContext.ResultOperator).ReturnDefaultWhenEmpty &&
handlerContext.QueryModelVisitor.ParentQueryModelVisitor != null;
return(handlerContext.EvalOnClient(requiresClientResultOperator));
}
private static Expression HandleDefaultIfEmpty(HandlerContext handlerContext)
{
var defaultIfEmptyResultOperator = (DefaultIfEmptyResultOperator)handlerContext.ResultOperator;
if (defaultIfEmptyResultOperator.OptionalDefaultValue != null)
{
return(handlerContext.EvalOnClient());
}
var selectExpression = handlerContext.SelectExpression;
selectExpression.PushDownSubquery();
selectExpression.ExplodeStarProjection();
var subquery = selectExpression.Tables.Single();
selectExpression.ClearTables();
var emptySelectExpression = handlerContext.SelectExpressionFactory.Create(handlerContext.QueryModelVisitor.QueryCompilationContext, "empty");
emptySelectExpression.AddToProjection(new AliasExpression("empty", Expression.Constant(null)));
selectExpression.AddTable(emptySelectExpression);
var leftOuterJoinExpression = new LeftOuterJoinExpression(subquery);
var constant1 = Expression.Constant(1);
leftOuterJoinExpression.Predicate = Expression.Equal(constant1, constant1);
selectExpression.AddTable(leftOuterJoinExpression);
selectExpression.ProjectStarTable = subquery;
handlerContext.QueryModelVisitor.Expression
= new DefaultIfEmptyExpressionVisitor(
handlerContext.QueryModelVisitor.QueryCompilationContext)
.Visit(handlerContext.QueryModelVisitor.Expression);
return(handlerContext.EvalOnClient(requiresClientResultOperator: false));
}
private static Expression HandleSingle(HandlerContext handlerContext)
{
handlerContext.SelectExpression.Limit = Expression.Constant(2);
var returnExpression = handlerContext.EvalOnClient(requiresClientResultOperator: true);
// For top level single, we do not require client eval
if (handlerContext.QueryModelVisitor.ParentQueryModelVisitor == null)
{
handlerContext.QueryModelVisitor.RequiresClientResultOperator = false;
}
return(returnExpression);
}
private static Expression HandleSum(HandlerContext handlerContext)
{
if (!handlerContext.QueryModelVisitor.RequiresClientProjection)
{
var sumExpression
= new SumExpression(handlerContext.SelectExpression.Projection.Single());
handlerContext.SelectExpression.SetProjectionExpression(sumExpression);
return((Expression)_transformClientExpressionMethodInfo
.MakeGenericMethod(sumExpression.Type)
.Invoke(null, new object[] { handlerContext }));
}
return(handlerContext.EvalOnClient());
}
private static Expression HandleAll(HandlerContext handlerContext)
{
var sqlTranslatingVisitor
= handlerContext.CreateSqlTranslatingVisitor(bindParentQueries: true);
var predicate
= sqlTranslatingVisitor.Visit(
((AllResultOperator)handlerContext.ResultOperator).Predicate);
if (predicate != null)
{
var innerSelectExpression = handlerContext.SelectExpression.Clone();
innerSelectExpression.ClearProjection();
innerSelectExpression.AddToProjection(Expression.Constant(1));
if (handlerContext.SelectExpression.Predicate != null)
{
innerSelectExpression.Predicate
= Expression.AndAlso(
handlerContext.SelectExpression.Predicate,
Expression.Not(predicate));
}
else
{
innerSelectExpression.Predicate = Expression.Not(predicate);
}
if (innerSelectExpression.Limit == null &&
innerSelectExpression.Offset == null)
{
innerSelectExpression.ClearOrderBy();
}
SetProjectionConditionalExpression(
handlerContext,
Expression.Condition(
Expression.Not(new ExistsExpression(innerSelectExpression)),
Expression.Constant(true),
Expression.Constant(false),
typeof(bool)));
return(TransformClientExpression <bool>(handlerContext));
}
return(handlerContext.EvalOnClient());
}
private static Expression HandleAverage(HandlerContext handlerContext)
{
if (!handlerContext.QueryModelVisitor.RequiresClientProjection &&
handlerContext.SelectExpression.Projection.Count == 1)
{
PrepareSelectExpressionForAggregate(handlerContext.SelectExpression);
var expression = handlerContext.SelectExpression.Projection.First();
if (!(expression.RemoveConvert() is SelectExpression))
{
var inputType = handlerContext.QueryModel.SelectClause.Selector.Type;
var outputType = inputType;
var nonNullableInputType = inputType.UnwrapNullableType();
if (nonNullableInputType == typeof(int) ||
nonNullableInputType == typeof(long))
{
outputType = inputType.IsNullableType() ? typeof(double?) : typeof(double);
}
expression = (expression as ExplicitCastExpression)?.Operand ?? expression;
expression = UnwrapAliasExpression(expression);
expression = new ExplicitCastExpression(expression, outputType);
Expression averageExpression = new SqlFunctionExpression(
"AVG",
outputType,
new[] { expression });
if (nonNullableInputType == typeof(float))
{
averageExpression = new ExplicitCastExpression(averageExpression, inputType);
}
handlerContext.SelectExpression.SetProjectionExpression(averageExpression);
var averageExpressionType = averageExpression.Type;
var throwOnNullResult = DetermineAggregateThrowingBehavior(handlerContext, averageExpressionType);
return((Expression)_transformClientExpressionMethodInfo
.MakeGenericMethod(averageExpressionType)
.Invoke(null, new object[] { handlerContext, throwOnNullResult }));
}
}
return(handlerContext.EvalOnClient());
}
private static Expression HandleTake(HandlerContext handlerContext)
{
var takeResultOperator = (TakeResultOperator)handlerContext.ResultOperator;
var sqlTranslatingExpressionVisitor = handlerContext.CreateSqlTranslatingVisitor(bindParentQueries: true);
var limit = sqlTranslatingExpressionVisitor.Visit(takeResultOperator.Count);
if (limit != null)
{
handlerContext.SelectExpression.Limit = takeResultOperator.Count;
return(handlerContext.EvalOnServer);
}
return(handlerContext.EvalOnClient());
}
private static Expression HandleLast(HandlerContext handlerContext)
{
if (handlerContext.SelectExpression.OrderBy.Any())
{
foreach (var ordering in handlerContext.SelectExpression.OrderBy)
{
ordering.OrderingDirection
= ordering.OrderingDirection == OrderingDirection.Asc
? OrderingDirection.Desc
: OrderingDirection.Asc;
}
handlerContext.SelectExpression.Limit = Expression.Constant(1);
}
return(handlerContext.EvalOnClient(requiresClientResultOperator: false));
}
private static Expression HandleSkip(HandlerContext handlerContext)
{
var skipResultOperator = (SkipResultOperator)handlerContext.ResultOperator;
var sqlTranslatingExpressionVisitor = handlerContext.CreateSqlTranslatingVisitor(bindParentQueries: true);
var offset = sqlTranslatingExpressionVisitor.Visit(skipResultOperator.Count);
if (offset != null)
{
handlerContext.SelectExpression.Offset = offset;
return(handlerContext.EvalOnServer);
}
return(handlerContext.EvalOnClient());
}
private static Expression HandleGroup(HandlerContext handlerContext)
{
var sqlTranslatingExpressionVisitor
= handlerContext.SqlTranslatingExpressionVisitorFactory
.Create(
handlerContext.QueryModelVisitor,
handlerContext.SelectExpression);
var groupResultOperator = (GroupResultOperator)handlerContext.ResultOperator;
var sqlExpression
= sqlTranslatingExpressionVisitor.Visit(groupResultOperator.KeySelector);
if (sqlExpression != null)
{
handlerContext.SelectExpression.ClearOrderBy();
var columns = (sqlExpression as ConstantExpression)?.Value as Expression[];
if (columns != null)
{
foreach (var column in columns)
{
handlerContext.SelectExpression
.AddToOrderBy(new Ordering(column, OrderingDirection.Asc));
}
}
else
{
handlerContext.SelectExpression
.AddToOrderBy(new Ordering(sqlExpression, OrderingDirection.Asc));
}
}
var oldGroupByCall = (MethodCallExpression)handlerContext.EvalOnClient();
return(Expression.Call(
handlerContext.QueryModelVisitor.QueryCompilationContext.QueryMethodProvider.GroupByMethod
.MakeGenericMethod(oldGroupByCall.Method.GetGenericArguments()),
oldGroupByCall.Arguments));
}
private static Expression HandleAll(HandlerContext handlerContext)
{
var filteringVisitor
= handlerContext.SqlTranslatingExpressionVisitorFactory
.Create(
handlerContext.QueryModelVisitor,
handlerContext.SelectExpression);
var predicate
= filteringVisitor.Visit(
((AllResultOperator)handlerContext.ResultOperator).Predicate);
if (predicate != null)
{
var innerSelectExpression
= handlerContext.SelectExpressionFactory.Create(handlerContext.QueryModelVisitor.QueryCompilationContext);
innerSelectExpression.AddTables(handlerContext.SelectExpression.Tables);
innerSelectExpression.Predicate = Expression.Not(predicate);
if (handlerContext.SelectExpression.Predicate != null)
{
innerSelectExpression.Predicate
= Expression.AndAlso(
handlerContext.SelectExpression.Predicate,
innerSelectExpression.Predicate);
}
SetProjectionConditionalExpression(
handlerContext,
Expression.Condition(
Expression.Not(new ExistsExpression(innerSelectExpression)),
Expression.Constant(true),
Expression.Constant(false),
typeof(bool)));
return(TransformClientExpression <bool>(handlerContext));
}
return(handlerContext.EvalOnClient());
}
private static Expression HandleSum(HandlerContext handlerContext)
{
if (!handlerContext.QueryModelVisitor.RequiresClientProjection &&
handlerContext.SelectExpression.Projection.Count == 1)
{
var expression = handlerContext.SelectExpression.Projection.First();
if (!(expression.RemoveConvert() is SelectExpression))
{
var sumExpression = new SqlFunctionExpression("SUM", expression.Type, new [] { expression });
handlerContext.SelectExpression.SetProjectionExpression(sumExpression);
return((Expression)_transformClientExpressionMethodInfo
.MakeGenericMethod(sumExpression.Type)
.Invoke(null, new object [] { handlerContext }));
}
}
return(handlerContext.EvalOnClient());
}
public virtual Expression HandleResultOperator(
EntityQueryModelVisitor entityQueryModelVisitor,
ResultOperatorBase resultOperator,
QueryModel queryModel)
{
var relationalQueryModelVisitor
= (RelationalQueryModelVisitor)entityQueryModelVisitor;
var selectExpression
= relationalQueryModelVisitor
.TryGetQuery(queryModel.MainFromClause);
var handlerContext
= new HandlerContext(
_resultOperatorHandler,
_model,
_relationalAnnotationProvider,
_sqlTranslatingExpressionVisitorFactory,
_selectExpressionFactory,
relationalQueryModelVisitor,
resultOperator,
queryModel,
selectExpression);
Func <HandlerContext, Expression> resultHandler;
if (relationalQueryModelVisitor.RequiresClientFilter ||
relationalQueryModelVisitor.RequiresClientResultOperator ||
relationalQueryModelVisitor.RequiresClientSelectMany ||
!_resultHandlers.TryGetValue(resultOperator.GetType(), out resultHandler) ||
selectExpression == null)
{
return(handlerContext.EvalOnClient());
}
return(resultHandler(handlerContext));
}
private static Expression HandleContains(HandlerContext handlerContext)
{
var filteringVisitor = handlerContext.CreateSqlTranslatingVisitor();
var itemResultOperator = (ContainsResultOperator)handlerContext.ResultOperator;
var item = filteringVisitor.Visit(itemResultOperator.Item);
if (item != null)
{
if (item is SelectExpression itemSelectExpression)
{
var queryCompilationContext = handlerContext.QueryModelVisitor.QueryCompilationContext;
var entityType = queryCompilationContext.FindEntityType(handlerContext.QueryModel.MainFromClause)
?? handlerContext.Model.FindEntityType(handlerContext.QueryModel.MainFromClause.ItemType);
if (entityType != null)
{
var outerSelectExpression = handlerContext.SelectExpressionFactory.Create(queryCompilationContext);
var collectionSelectExpression
= handlerContext.SelectExpression.Clone(queryCompilationContext.CreateUniqueTableAlias());
outerSelectExpression.AddTable(collectionSelectExpression);
itemSelectExpression.Alias = queryCompilationContext.CreateUniqueTableAlias();
var joinExpression = outerSelectExpression.AddInnerJoin(itemSelectExpression);
foreach (var property in entityType.FindPrimaryKey().Properties)
{
var itemProperty = itemSelectExpression.BindProperty(
property,
itemSelectExpression.ProjectStarTable.QuerySource);
itemSelectExpression.AddToProjection(itemProperty);
var collectionProperty = collectionSelectExpression.BindProperty(
property,
collectionSelectExpression.ProjectStarTable.QuerySource);
collectionSelectExpression.AddToProjection(collectionProperty);
var predicate = Expression.Equal(
collectionProperty.LiftExpressionFromSubquery(collectionSelectExpression),
itemProperty.LiftExpressionFromSubquery(itemSelectExpression));
joinExpression.Predicate
= joinExpression.Predicate == null
? predicate
: Expression.AndAlso(
joinExpression.Predicate,
predicate);
}
SetConditionAsProjection(
handlerContext,
new ExistsExpression(outerSelectExpression));
return(TransformClientExpression <bool>(handlerContext));
}
}
SetConditionAsProjection(
handlerContext,
new InExpression(
item,
handlerContext.SelectExpression.Clone("")));
return(TransformClientExpression <bool>(handlerContext));
}
return(handlerContext.EvalOnClient());
}
private static Expression HandleContains(HandlerContext handlerContext)
{
var filteringVisitor = handlerContext.CreateSqlTranslatingVisitor(bindParentQueries: true);
var itemResultOperator = (ContainsResultOperator)handlerContext.ResultOperator;
var item = filteringVisitor.Visit(itemResultOperator.Item);
if (item != null)
{
var itemSelectExpression = item as SelectExpression;
if (itemSelectExpression != null)
{
var entityType = handlerContext.Model.FindEntityType(handlerContext.QueryModel.MainFromClause.ItemType);
if (entityType != null)
{
var outterSelectExpression = handlerContext.SelectExpressionFactory.Create(handlerContext.QueryModelVisitor.QueryCompilationContext);
outterSelectExpression.SetProjectionExpression(Expression.Constant(1));
var collectionSelectExpression
= handlerContext.SelectExpression.Clone(handlerContext.QueryModelVisitor.QueryCompilationContext.CreateUniqueTableAlias());
outterSelectExpression.AddTable(collectionSelectExpression);
itemSelectExpression.Alias = handlerContext.QueryModelVisitor.QueryCompilationContext.CreateUniqueTableAlias();
var joinExpression = outterSelectExpression.AddInnerJoin(itemSelectExpression);
foreach (var property in entityType.FindPrimaryKey().Properties)
{
itemSelectExpression.AddToProjection(
new ColumnExpression(
property.Name,
property,
itemSelectExpression.Tables.First()));
collectionSelectExpression.AddToProjection(
new ColumnExpression(
property.Name,
property,
collectionSelectExpression.Tables.First()));
var predicate = Expression.Equal(
new ColumnExpression(
property.Name,
property,
collectionSelectExpression),
new ColumnExpression(
property.Name,
property,
itemSelectExpression));
joinExpression.Predicate
= joinExpression.Predicate == null
? predicate
: Expression.AndAlso(
joinExpression.Predicate,
predicate);
}
SetProjectionConditionalExpression(
handlerContext,
Expression.Condition(
new ExistsExpression(outterSelectExpression),
Expression.Constant(true),
Expression.Constant(false),
typeof(bool)));
return(TransformClientExpression <bool>(handlerContext));
}
}
SetProjectionConditionalExpression(
handlerContext,
Expression.Condition(
new InExpression(
new AliasExpression(item),
handlerContext.SelectExpression.Clone("")),
Expression.Constant(true),
Expression.Constant(false),
typeof(bool)));
return(TransformClientExpression <bool>(handlerContext));
}
return(handlerContext.EvalOnClient());
}
private static Expression HandleCast(HandlerContext handlerContext) => handlerContext.EvalOnClient(requiresClientResultOperator: false);
private static Expression HandleOfType(HandlerContext handlerContext)
{
var ofTypeResultOperator
= (OfTypeResultOperator)handlerContext.ResultOperator;
var entityType = handlerContext.Model.FindEntityType(ofTypeResultOperator.SearchedItemType);
if (entityType == null)
{
return(handlerContext.EvalOnClient());
}
var concreteEntityTypes
= entityType.GetConcreteTypesInHierarchy().ToArray();
if (concreteEntityTypes.Length != 1 ||
concreteEntityTypes[0].RootType() != concreteEntityTypes[0])
{
var relationalMetadataExtensionProvider
= handlerContext.RelationalAnnotationProvider;
var discriminatorProperty
= relationalMetadataExtensionProvider.For(concreteEntityTypes[0]).DiscriminatorProperty;
var projectionIndex
= handlerContext.SelectExpression
.GetProjectionIndex(discriminatorProperty, handlerContext.QueryModel.MainFromClause);
if (projectionIndex < 0)
{
projectionIndex
= handlerContext.SelectExpression
.AddToProjection(
relationalMetadataExtensionProvider.For(discriminatorProperty).ColumnName,
discriminatorProperty,
handlerContext.QueryModel.MainFromClause);
}
var discriminatorColumn
= handlerContext.SelectExpression.Projection[projectionIndex];
var discriminatorPredicate
= concreteEntityTypes
.Select(concreteEntityType =>
Expression.Equal(
discriminatorColumn,
Expression.Constant(relationalMetadataExtensionProvider.For(concreteEntityType).DiscriminatorValue)))
.Aggregate((current, next) => Expression.OrElse(next, current));
handlerContext.SelectExpression.Predicate
= new DiscriminatorReplacingExpressionVisitor(
discriminatorPredicate,
handlerContext.QueryModel.MainFromClause)
.Visit(handlerContext.SelectExpression.Predicate);
}
return(Expression.Call(
handlerContext.QueryModelVisitor.QueryCompilationContext.LinqOperatorProvider.Cast
.MakeGenericMethod(ofTypeResultOperator.SearchedItemType),
handlerContext.QueryModelVisitor.Expression));
}
private static Expression HandleFirst(HandlerContext handlerContext)
{
handlerContext.SelectExpression.Limit = Expression.Constant(1);
return(handlerContext.EvalOnClient(requiresClientResultOperator: false));
}
private static Expression HandleOfType(HandlerContext handlerContext)
{
var ofTypeResultOperator
= (OfTypeResultOperator)handlerContext.ResultOperator;
var entityType = handlerContext.Model.FindEntityType(ofTypeResultOperator.SearchedItemType);
if (entityType == null)
{
return(handlerContext.EvalOnClient());
}
var concreteEntityTypes
= entityType.GetConcreteTypesInHierarchy().ToArray();
if (concreteEntityTypes.Length != 1 ||
concreteEntityTypes[0].RootType() != concreteEntityTypes[0])
{
var relationalMetadataExtensionProvider
= handlerContext.RelationalAnnotationProvider;
var discriminatorProperty
= relationalMetadataExtensionProvider.For(concreteEntityTypes[0]).DiscriminatorProperty;
var projectionIndex
= handlerContext.SelectExpression
.GetProjectionIndex(discriminatorProperty, handlerContext.QueryModel.MainFromClause);
if (projectionIndex < 0)
{
projectionIndex
= handlerContext.SelectExpression
.AddToProjection(
relationalMetadataExtensionProvider.For(discriminatorProperty).ColumnName,
discriminatorProperty,
handlerContext.QueryModel.MainFromClause);
}
var discriminatorColumn
= handlerContext.SelectExpression.Projection[projectionIndex];
var discriminatorPredicate
= concreteEntityTypes
.Select(concreteEntityType =>
Expression.Equal(
discriminatorColumn,
Expression.Constant(relationalMetadataExtensionProvider.For(concreteEntityType).DiscriminatorValue)))
.Aggregate((current, next) => Expression.OrElse(next, current));
handlerContext.SelectExpression.Predicate
= new DiscriminatorReplacingExpressionVisitor(
discriminatorPredicate,
handlerContext.QueryModel.MainFromClause)
.Visit(handlerContext.SelectExpression.Predicate);
}
var shapedQueryMethod = (MethodCallExpression)handlerContext.QueryModelVisitor.Expression;
var entityShaper = (EntityShaper)((ConstantExpression)shapedQueryMethod.Arguments[2]).Value;
return(Expression.Call(
shapedQueryMethod.Method
.GetGenericMethodDefinition()
.MakeGenericMethod(ofTypeResultOperator.SearchedItemType),
shapedQueryMethod.Arguments[0],
shapedQueryMethod.Arguments[1],
Expression.Constant(
_createDowncastingShaperMethodInfo
.MakeGenericMethod(ofTypeResultOperator.SearchedItemType)
.Invoke(null, new object[] { entityShaper }))));
}
private static Expression HandleSingle(HandlerContext handlerContext)
{
handlerContext.SelectExpression.Limit = Expression.Constant(2);
return(handlerContext.EvalOnClient(requiresClientResultOperator: true));
}
