protected override Expression VisitSelect(SelectExpression select)
{
var saveIsOuterMostSelect = _isOutermostSelect;
try
{
_isOutermostSelect = false;
select = (SelectExpression)base.VisitSelect(select);
var hasOrderBy = select.OrderBy != null && select.OrderBy.Count > 0;
var hasGroupBy = select.GroupBy != null;
var canHaveOrderings = saveIsOuterMostSelect || select.Take != null || select.Skip != null;
var canReceivedOrderings = canHaveOrderings && !hasGroupBy && !select.IsDistinct;
if (hasOrderBy)
PrependOrderings(select.OrderBy);
IEnumerable<OrderExpression> orderings = null;
if (canReceivedOrderings)
orderings = _gatheredOrderings;
else if (canHaveOrderings)
orderings = select.OrderBy;
var canPassOnOrderings = !saveIsOuterMostSelect && !hasGroupBy && !select.IsDistinct;
ReadOnlyCollection<FieldDeclaration> fields = select.Fields;
if (_gatheredOrderings != null)
{
if (canPassOnOrderings)
{
var producedAliases = new DeclaredAliasGatherer().Gather(select.From);
BindResult project = RebindOrderings(_gatheredOrderings, select.Alias, producedAliases, select.Fields);
_gatheredOrderings = null;
PrependOrderings(project.Orderings);
fields = project.Fields;
}
else
_gatheredOrderings = null;
}
if (orderings != select.OrderBy || fields != select.Fields)
select = new SelectExpression(select.Alias, fields, select.From, select.Where, orderings, select.GroupBy, select.IsDistinct, select.Skip, select.Take);
return select;
}
finally
{
_isOutermostSelect = saveIsOuterMostSelect;
}
}
private void MapAliases(Expression a, Expression b)
{
var gatherer = new DeclaredAliasGatherer();
Alias[] prodA = gatherer.Gather(a).ToArray();
Alias[] prodB = gatherer.Gather(b).ToArray();
for (int i = 0, n = prodA.Length; i < n; i++)
{
_aliasScope.Add(prodA[i], prodB[i]);
}
}
