internal Expression CreatePropertyValueExpressionWithFilter(IEdmEntityType elementType, IEdmProperty property,
Expression source, FilterClause filterClause)
{
Contract.Assert(elementType != null);
Contract.Assert(property != null);
Contract.Assert(source != null);
IEdmEntityType declaringType = property.DeclaringType as IEdmEntityType;
Contract.Assert(declaringType != null, "only entity types are projected.");
// derived property using cast
if (elementType != declaringType)
{
Type castType = EdmLibHelpers.GetClrType(declaringType, _model);
if (castType == null)
{
throw new ODataException(Error.Format(SRResources.MappingDoesNotContainResourceType,
declaringType.FullName()));
}
source = Expression.TypeAs(source, castType);
}
string propertyName = EdmLibHelpers.GetClrPropertyName(property, _model);
Expression propertyValue = ExpressionBinderBase.GetPropertyExpression(source, propertyName);
Type nullablePropertyType = propertyValue.Type.ToNullable();
Expression nullablePropertyValue = ExpressionHelpers.ToNullable(propertyValue);
if (filterClause != null)
{
var isCollection = property.Type.IsCollection();
IEdmTypeReference edmElementType = (isCollection ? property.Type.AsCollection().ElementType() : property.Type);
Type clrElementType = EdmLibHelpers.GetClrType(edmElementType, _model);
if (clrElementType == null)
{
throw new ODataException(Error.Format(SRResources.MappingDoesNotContainResourceType,
edmElementType.FullName()));
}
Expression filterResult = nullablePropertyValue;
if (isCollection)
{
Expression filterSource =
typeof(IEnumerable).IsAssignableFrom(source.Type.GetProperty(propertyName).PropertyType)
? Expression.Call(
ExpressionHelperMethods.QueryableAsQueryable.MakeGenericMethod(clrElementType),
nullablePropertyValue)
: nullablePropertyValue;
// TODO: Implement proper support for $select/$expand after $apply
Expression filterPredicate = FilterBinder.Bind(null, filterClause, clrElementType, _context.RequestContainer);
filterResult = Expression.Call(
ExpressionHelperMethods.QueryableWhereGeneric.MakeGenericMethod(clrElementType),
filterSource,
filterPredicate);
nullablePropertyType = filterResult.Type;
}
else if (_settings.HandleReferenceNavigationPropertyExpandFilter)
{
var filterLambdaExpression = FilterBinder.Bind(null, filterClause, clrElementType, _context.RequestContainer) as LambdaExpression;
if (filterLambdaExpression == null)
{
throw new ODataException(Error.Format(SRResources.ExpandFilterExpressionNotLambdaExpression,
property.Name, nameof(LambdaExpression)));
}
var filterParameter = filterLambdaExpression.Parameters.First();
var predicateExpression = new ReferenceNavigationPropertyExpandFilterVisitor(filterParameter, nullablePropertyValue).Visit(filterLambdaExpression.Body);
// predicateExpression == true ? nullablePropertyValue : null
filterResult = Expression.Condition(
test: predicateExpression,
ifTrue: nullablePropertyValue,
ifFalse: Expression.Constant(value: null, type: nullablePropertyType));
}
if (_settings.HandleNullPropagation == HandleNullPropagationOption.True)
{
// nullablePropertyValue == null ? null : filterResult
nullablePropertyValue = Expression.Condition(
test: Expression.Equal(nullablePropertyValue, Expression.Constant(value: null)),
ifTrue: Expression.Constant(value: null, type: nullablePropertyType),
ifFalse: filterResult);
}
else
{
nullablePropertyValue = filterResult;
}
}
if (_settings.HandleNullPropagation == HandleNullPropagationOption.True)
{
// source == null ? null : propertyValue
propertyValue = Expression.Condition(
test: Expression.Equal(source, Expression.Constant(value: null)),
ifTrue: Expression.Constant(value: null, type: nullablePropertyType),
ifFalse: nullablePropertyValue);
}
else
{
// need to cast this to nullable as EF would fail while materializing if the property is not nullable and source is null.
propertyValue = nullablePropertyValue;
}
return(propertyValue);
}
private Expression CreatePropertyAccessExpression(Expression source, IEdmProperty property, string propertyPath = null)
{
string propertyName = EdmLibHelpers.GetClrPropertyName(property, Model);
propertyPath = propertyPath ?? propertyName;
if (QuerySettings.HandleNullPropagation == HandleNullPropagationOption.True && IsNullable(source.Type) &&
source != this._lambdaParameter)
{
Expression cleanSource = RemoveInnerNullPropagation(source);
Expression propertyAccessExpression = null;
propertyAccessExpression = GetFlattenedPropertyExpression(propertyPath) ?? Expression.Property(cleanSource, propertyName);
// source.property => source == null ? null : [CastToNullable]RemoveInnerNullPropagation(source).property
// Notice that we are checking if source is null already. so we can safely remove any null checks when doing source.Property
Expression ifFalse = ToNullable(ConvertNonStandardPrimitives(propertyAccessExpression));
return
(Expression.Condition(
test: Expression.Equal(source, NullConstant),
ifTrue: Expression.Constant(null, ifFalse.Type),
ifFalse: ifFalse));
}
else
{
return(GetFlattenedPropertyExpression(propertyPath) ?? ConvertNonStandardPrimitives(ExpressionBinderBase.GetPropertyExpression(source, propertyName)));
}
}