protected override Expression VisitTypeBinary(TypeBinaryExpression typeBinaryExpression)
{
Check.NotNull(typeBinaryExpression, nameof(typeBinaryExpression));
if (typeBinaryExpression.NodeType == ExpressionType.TypeIs &&
Visit(typeBinaryExpression.Expression) is EntityProjectionExpression entityProjectionExpression)
{
var entityType = entityProjectionExpression.EntityType;
if (entityType.GetAllBaseTypesInclusive().Any(et => et.ClrType == typeBinaryExpression.TypeOperand))
{
return(SqlExpressionFactory.Constant(true));
}
var derivedType = entityType.GetDerivedTypes().SingleOrDefault(et => et.ClrType == typeBinaryExpression.TypeOperand);
if (derivedType != null)
{
var concreteEntityTypes = derivedType.GetConcreteDerivedTypesInclusive().ToList();
var discriminatorColumn = entityProjectionExpression.BindProperty(entityType.GetDiscriminatorProperty());
return(concreteEntityTypes.Count == 1
? SqlExpressionFactory.Equal(
discriminatorColumn,
SqlExpressionFactory.Constant(concreteEntityTypes[0].GetDiscriminatorValue()))
: (Expression)SqlExpressionFactory.In(
discriminatorColumn,
SqlExpressionFactory.Constant(concreteEntityTypes.Select(et => et.GetDiscriminatorValue()).ToList()),
negated: false));
}
return(SqlExpressionFactory.Constant(false));
}
return(null);
}
protected override Expression VisitExtension(Expression extensionExpression)
{
if (extensionExpression is SelectExpression selectExpression)
{
var newSelectExpression = (SelectExpression)base.VisitExtension(extensionExpression);
return(newSelectExpression.Predicate is SqlConstantExpression newSelectPredicateConstant &&
!(selectExpression.Predicate is SqlConstantExpression)
? newSelectExpression.Update(
newSelectExpression.Projection.ToList(),
newSelectExpression.Tables.ToList(),
SqlExpressionFactory.Equal(
newSelectPredicateConstant,
SqlExpressionFactory.Constant(true, newSelectPredicateConstant.TypeMapping)),
newSelectExpression.GroupBy.ToList(),
newSelectExpression.Having,
newSelectExpression.Orderings.ToList(),
newSelectExpression.Limit,
newSelectExpression.Offset,
newSelectExpression.IsDistinct,
newSelectExpression.Alias)
: newSelectExpression);
}
return(base.VisitExtension(extensionExpression));
}
protected override Expression VisitExtension(Expression extensionExpression)
{
if (extensionExpression is SelectExpression selectExpression)
{
var newSelectExpression = (SelectExpression)base.VisitExtension(extensionExpression);
// if predicate is optimized to true, we can simply remove it
var newPredicate = newSelectExpression.Predicate is SqlConstantExpression newSelectPredicateConstant &&
!(selectExpression.Predicate is SqlConstantExpression)
? (bool)newSelectPredicateConstant.Value
? null
: SqlExpressionFactory.Equal(
newSelectPredicateConstant,
SqlExpressionFactory.Constant(true, newSelectPredicateConstant.TypeMapping))
: newSelectExpression.Predicate;
var newHaving = newSelectExpression.Having is SqlConstantExpression newSelectHavingConstant &&
!(selectExpression.Having is SqlConstantExpression)
? (bool)newSelectHavingConstant.Value
? null
: SqlExpressionFactory.Equal(
newSelectHavingConstant,
SqlExpressionFactory.Constant(true, newSelectHavingConstant.TypeMapping))
: newSelectExpression.Having;
return(newPredicate != newSelectExpression.Predicate ||
newHaving != newSelectExpression.Having
? newSelectExpression.Update(
newSelectExpression.Projection.ToList(),
newSelectExpression.Tables.ToList(),
newPredicate,
newSelectExpression.GroupBy.ToList(),
newHaving,
newSelectExpression.Orderings.ToList(),
newSelectExpression.Limit,
newSelectExpression.Offset,
newSelectExpression.IsDistinct,
newSelectExpression.Alias)
: newSelectExpression);
}
return(base.VisitExtension(extensionExpression));
}