public override Expression Visit(Expression node)
{
IEnumerable <string> GetNameParts()
{
return(nameStack.Reverse().Where(n => n != null && !n.StartsWith("<>")));
}
switch (node)
{
case null:
{
return(null);
}
case NewExpression newExpression:
{
if (newExpression.Members == null)
{
return(newExpression);
}
var arguments = newExpression.Arguments.ToArray();
for (var i = 0; i < newExpression.Members.Count; i++)
{
nameStack.Push(newExpression.Members[i].GetPathSegmentName());
arguments[i] = Visit(arguments[i]);
nameStack.Pop();
}
return(newExpression.Update(arguments));
}
case MemberInitExpression memberInitExpression:
{
var newExpression = (NewExpression)Visit(memberInitExpression.NewExpression);
var bindings = memberInitExpression.Bindings.ToArray();
for (var i = 0; i < bindings.Length; i++)
{
nameStack.Push(bindings[i].Member.GetPathSegmentName());
bindings[i] = VisitMemberBinding(bindings[i]);
nameStack.Pop();
}
return(memberInitExpression.Update(newExpression, bindings));
}
case ExtendedNewExpression newExpression:
{
var arguments = newExpression.Arguments.ToArray();
for (var i = 0; i < newExpression.Arguments.Count; i++)
{
nameStack.Push(newExpression.ReadableMembers[i].GetPathSegmentName());
arguments[i] = Visit(arguments[i]);
nameStack.Pop();
}
return(newExpression.Update(arguments));
}
case ExtendedMemberInitExpression memberInitExpression:
{
var newExpression = (ExtendedNewExpression)Visit(memberInitExpression.NewExpression);
var arguments = memberInitExpression.Arguments.ToArray();
for (var i = 0; i < arguments.Length; i++)
{
nameStack.Push(memberInitExpression.ReadableMembers[i].GetPathSegmentName());
arguments[i] = Visit(arguments[i]);
nameStack.Pop();
}
return(memberInitExpression.Update(newExpression, arguments));
}
case NewArrayExpression newArrayExpression:
{
var expressions = new Expression[newArrayExpression.Expressions.Count];
for (var i = 0; i < newArrayExpression.Expressions.Count; i++)
{
nameStack.Push($"${i}");
expressions[i] = Visit(newArrayExpression.Expressions[i]);
nameStack.Pop();
}
return(newArrayExpression.Update(expressions));
}
case GroupByResultExpression groupByResultExpression:
{
var uniquifier = new TableUniquifyingExpressionVisitor();
var oldSelectExpression = groupByResultExpression.SelectExpression;
var newSelectExpression = uniquifier.VisitAndConvert(oldSelectExpression, nameof(Visit));
var oldTables = oldSelectExpression.Table.Flatten().ToArray();
var newTables = newSelectExpression.Table.Flatten().ToArray();
var updater = new TableUpdatingExpressionVisitor(oldTables, newTables);
nameStack.Push("Key");
var outerKeySelector = Visit(groupByResultExpression.OuterKeySelector);
var innerKeySelector = updater.Visit(groupByResultExpression.InnerKeySelector);
var elementSelector = updater.Visit(groupByResultExpression.ElementSelector);
nameStack.Pop();
return(new GroupedRelationalQueryExpression(
newSelectExpression.UpdateProjection(new ServerProjectionExpression(elementSelector)),
outerKeySelector,
innerKeySelector,
groupByResultExpression.InnerKeyLambda,
requiresDenullification: false,
type: groupByResultExpression.Type));
}
case GroupedRelationalQueryExpression groupedRelationalQueryExpression:
{
var uniquifier = new TableUniquifyingExpressionVisitor();
var oldSelectExpression = groupedRelationalQueryExpression.SelectExpression;
var newSelectExpression = uniquifier.VisitAndConvert(oldSelectExpression, nameof(Visit));
var oldTables = oldSelectExpression.Table.Flatten().ToArray();
var newTables = newSelectExpression.Table.Flatten().ToArray();
var updater = new TableUpdatingExpressionVisitor(oldTables, newTables);
nameStack.Push("Key");
var outerKeySelector = Visit(groupedRelationalQueryExpression.OuterKeySelector);
var innerKeySelector = updater.Visit(groupedRelationalQueryExpression.InnerKeySelector);
nameStack.Pop();
return(new GroupedRelationalQueryExpression(
newSelectExpression,
outerKeySelector,
innerKeySelector,
groupedRelationalQueryExpression.InnerKeyLambda,
groupedRelationalQueryExpression.RequiresDenullification,
groupedRelationalQueryExpression.Type));
}
case DefaultIfEmptyExpression defaultIfEmptyExpression:
{
var expression
= new SqlColumnNullabilityExpressionVisitor(true)
.Visit(Visit(defaultIfEmptyExpression.Expression));
var name = string.Join(".", GetNameParts().Append("$empty"));
var flag = new SqlColumnExpression(targetTable, name, typeof(bool?), true, null);
return(new DefaultIfEmptyExpression(expression, flag));
}
case PolymorphicExpression polymorphicExpression:
{
var row = Visit(polymorphicExpression.Row);
// TODO: Visit nested polymorphic expressions.
return(new PolymorphicExpression(
polymorphicExpression.Type,
row,
polymorphicExpression.Descriptors));
}
case ExtraPropertiesExpression extraPropertiesExpression:
{
var properties = new Expression[extraPropertiesExpression.Properties.Count];
for (var i = 0; i < extraPropertiesExpression.Properties.Count; i++)
{
var path = extraPropertiesExpression.GetMemberPath(i).ToArray();
if (path.Length == 0)
{
nameStack.Push(extraPropertiesExpression.Names[i]);
properties[i] = Visit(extraPropertiesExpression.Properties[i]);
nameStack.Pop();
}
else
{
for (var j = 0; j < path.Length; j++)
{
nameStack.Push(path[j].GetPathSegmentName());
}
properties[i] = Visit(extraPropertiesExpression.Properties[i]);
for (var j = 0; j < path.Length; j++)
{
nameStack.Pop();
}
}
}
var expression = Visit(extraPropertiesExpression.Expression);
return(extraPropertiesExpression.Update(expression, properties));
}
case LateBoundProjectionLeafExpression _:
{
return(node);
}
case AnnotationExpression annotationExpression:
{
return(base.Visit(annotationExpression));
}
case UnaryExpression unaryExpression
when unaryExpression.NodeType == ExpressionType.Convert:
{
return(unaryExpression.Update(Visit(unaryExpression.Operand)));
}
default:
{
var parts = GetNameParts();
var isNullable = node.Type.IsNullableType();
var typeMapping = default(ITypeMapping);
switch (node)
{
case SqlColumnExpression sqlColumnExpression:
{
parts = parts.DefaultIfEmpty(sqlColumnExpression.ColumnName);
isNullable = sqlColumnExpression.IsNullable;
typeMapping = sqlColumnExpression.TypeMapping;
break;
}
case SqlAliasExpression sqlAliasExpression:
{
parts = parts.DefaultIfEmpty(sqlAliasExpression.Alias);
break;
}
}
return(new SqlColumnExpression(
targetTable,
string.Join(".", parts),
node.Type,
isNullable,
typeMapping));
}
}
}
public override Expression Visit(Expression node)
{
var visited = base.Visit(node);
switch (visited)
{
case GroupByResultExpression groupByResultExpression:
{
var uniquifier = new TableUniquifyingExpressionVisitor();
var oldSelectExpression = groupByResultExpression.SelectExpression;
var newSelectExpression = uniquifier.VisitAndConvert(oldSelectExpression, nameof(VisitMethodCall));
var oldTables = oldSelectExpression.Table.Flatten().ToArray();
var newTables = newSelectExpression.Table.Flatten().ToArray();
var updater = new TableUpdatingExpressionVisitor(oldTables, newTables);
var outerKeySelector = groupByResultExpression.OuterKeySelector;
var innerKeySelector = updater.Visit(groupByResultExpression.InnerKeySelector);
var elementSelector = updater.Visit(groupByResultExpression.ElementSelector);
if (IsTranslatable(outerKeySelector) && IsTranslatable(innerKeySelector) && IsTranslatable(elementSelector))
{
var projection
= elementSelector
.VisitWith(postExpansionVisitors);
var predicate
= Expression
.Equal(outerKeySelector, innerKeySelector)
.VisitWith(postExpansionVisitors);
var query
= new EnumerableRelationalQueryExpression(
newSelectExpression
.UpdateProjection(new ServerProjectionExpression(projection))
.AddToPredicate(predicate));
return(ExpandedGrouping.Create(
groupByResultExpression.Type,
groupByResultExpression.OuterKeySelector,
query.AsList()));
}
else
{
throw new NotImplementedException();
}
}
case GroupedRelationalQueryExpression groupedRelationalQueryExpression:
{
var outerKeySelector = groupedRelationalQueryExpression.OuterKeySelector;
var innerKeySelector = groupedRelationalQueryExpression.InnerKeySelector;
if (IsTranslatable(outerKeySelector) && IsTranslatable(innerKeySelector))
{
if (groupedRelationalQueryExpression.RequiresDenullification)
{
outerKeySelector = JoinKeyDenullifyingExpressionVisitor.Instance.Visit(outerKeySelector);
innerKeySelector = JoinKeyDenullifyingExpressionVisitor.Instance.Visit(innerKeySelector);
}
var predicate
= Expression
.Equal(outerKeySelector, innerKeySelector)
.VisitWith(postExpansionVisitors);
var query
= new EnumerableRelationalQueryExpression(
groupedRelationalQueryExpression.SelectExpression
.AddToPredicate(predicate));
return(ExpandedGrouping.Create(
groupedRelationalQueryExpression.Type,
groupedRelationalQueryExpression.OuterKeySelector,
query.AsList()));
}
else
{
var predicate
= Expression.Lambda(
Expression.Equal(
outerKeySelector,
groupedRelationalQueryExpression.InnerKeyLambda.Body),
groupedRelationalQueryExpression.InnerKeyLambda.Parameters);
return(Expression.Call(
queryableWhere.MakeGenericMethod(groupedRelationalQueryExpression.Type.GetSequenceType()),
new EnumerableRelationalQueryExpression(groupedRelationalQueryExpression.SelectExpression),
Expression.Quote(predicate)));
}
}
default:
{
return(visited);
}
}
}
