internal SelectExpression(LambdaExpression projection, FromExpression from, WhereExpression where, string alias, bool isProjection, Expression take, OrderByClause orderBy)
: base(CompleteExpressionType.Select, typeof(IEnumerable<>).MakeGenericType(projection.ReturnType))
{
this.Projection = projection;
this.Alias = alias;
this.From = from;
this.Where = where;
this.Take = take;
this.OrderBy = orderBy;
this.IsProjection = isProjection;
var ce = ColumnExtractor.ExtractColumns(this, projection);
this._Columns = ce.Columns.ToList();
this._Assignments = ce.Assignments.ToList();
}
internal static OrderByClause CombineOrderByClauses(OrderByClause left, OrderByClause right)
{
// if left is null, then take right (null or no) and we're done
if (left == null)
return right;
// left is not null, start with clone of left
var orderBy = new OrderByClause(left.SecondarySortingClause);
orderBy._SortColumns.AddRange(left._SortColumns);
// if right is null, then we're done
if (right != null)
{
// right is not null; merge in sort columns from right at top level
left._SortColumns.AddRange(right._SortColumns);
// start with the highest level orderBy to figure out where to inject the right side sorting clause
// don't care about destroying existing clauses: these are cloned at every level anyway
// these order by clauses exist only for current level
var parent = orderBy;
while (parent.SecondarySortingClause != null)
parent = parent.SecondarySortingClause;
parent.SecondarySortingClause = right.SecondarySortingClause;
}
return orderBy;
}
internal OrderByClause(OrderByClause secondarySorts)
{
_SortColumns = new List<Tuple<Expression, SortDirection>>();
SecondarySortingClause = secondarySorts;
}
internal void InjectSecondarySortingClause(OrderByClause right)
{
var parent = this;
while (parent.SecondarySortingClause != null)
parent = parent.SecondarySortingClause;
parent.SecondarySortingClause = right;
}
protected virtual OrderByClause VisitOrderBy(OrderByClause orderBy)
{
if (orderBy == null)
return null;
var secondary = this.VisitOrderBy(orderBy.SecondarySortingClause);
var flag = secondary != orderBy.SecondarySortingClause;
var newOrderBy = new OrderByClause(secondary);
foreach (var col in orderBy.SortColumns)
{
var newCol = this.Visit(col.Item1);
newOrderBy.AppendColumn(Tuple.Create(newCol, col.Item2));
if (newCol != col.Item1)
flag = true;
}
if (flag)
return newOrderBy;
return orderBy;
}
protected override OrderByClause VisitOrderBy(OrderByClause orderBy)
{
var add_comma = false;
foreach (var col in orderBy.SortColumns)
{
if (add_comma)
sb.Append(", ");
else
add_comma = true;
this.Visit(col.Item1);
if (col.Item2 == OrderByClause.SortDirection.Ascending)
sb.Append(" asc");
else
sb.Append(" desc");
}
if (orderBy.SecondarySortingClause != null)
{
if (add_comma)
sb.Append(", ");
this.VisitOrderBy(orderBy.SecondarySortingClause);
}
this.AppendNewLine(Indentation.Same);
return orderBy;
}
protected virtual Expression VisitSelectManyMethod(MethodCallExpression m)
{
var select = VisitSource(m.Arguments[0]);
var selectSource = select.From.From as SourceExpression;
var collection = VisitSourceReferencedProjection(select.From, m.Arguments[1]);
var apply = collection.Body as SelectExpression;
var joinType = apply.DefaultIfEmpty ? JoinType.OuterApply : JoinType.CrossApply;
apply.DefaultIfEmpty = true;
var join = CompleteExpression.Join(selectSource, apply, joinType);
var from = CompleteExpression.From(join);
var orderBy = select.OrderBy;
var rightOrder = BuildNestedOrderBy(apply);
if (orderBy != null)
orderBy.InjectSecondarySortingClause(rightOrder);
else if (rightOrder != null)
orderBy = new OrderByClause(rightOrder);
var projection =
m.Arguments.Count() > 2 ?
VisitSourceReferencedProjection(from, m.Arguments[2]) :
ColumnReplacer.ReplaceColumns(apply.Projection) as LambdaExpression;
return CompleteExpression.Select(
GetNextAlias(),
projection,
from,
orderBy: orderBy,
where: select.Where,
isProjection: true);
}
private OrderByClause BuildNestedOrderBy(SelectExpression select, OrderByClause orderBy)
{
if (orderBy == null)
return null;
var newOrderBy = new OrderByClause(BuildNestedOrderBy(select, orderBy.SecondarySortingClause));
var columns = orderBy.SortColumns;
var unmatchedColumns = new List<Expression>();
foreach (var col in columns)
{
Expression expr = select.TryFindColumn(col.Item1);
if (expr == null)
expr = select.AddUnmappedColumn(col.Item1);
newOrderBy.AppendColumn(Tuple.Create(expr, col.Item2));
}
return newOrderBy;
}
public static SelectExpression Select(string alias, LambdaExpression projection, FromExpression from, OrderByClause orderBy, WhereExpression where = null, bool isProjection = true, Expression take = null)
{
return new SelectExpression(projection, from, where, alias, isProjection, take, orderBy);
}