protected override Expression VisitJoin(JoinExpression join)
{
join = (JoinExpression)base.VisitJoin(join);
if ((join.Join == JoinType.CrossApply) || (join.Join == JoinType.OuterApply))
{
if (join.Right is TableExpression)
{
return(new JoinExpression(JoinType.CrossJoin, join.Left, join.Right, null));
}
SelectExpression right = join.Right as SelectExpression;
if ((((right != null) && (right.Take == null)) && ((right.Skip == null) && !AggregateChecker.HasAggregates(right))) && ((right.GroupBy == null) || (right.GroupBy.Count == 0)))
{
SelectExpression source = right.SetWhere(null);
HashSet <TableAlias> set = ReferencedAliasGatherer.Gather(source);
HashSet <TableAlias> other = DeclaredAliasGatherer.Gather(join.Left);
set.IntersectWith(other);
if (set.Count == 0)
{
Expression where = right.Where;
right = source;
ProjectedColumns columns = ColumnProjector.ProjectColumns(this.language, where, right.Columns, right.Alias, DeclaredAliasGatherer.Gather(right.From));
right = right.SetColumns(columns.Columns);
where = columns.Projector;
return(new JoinExpression((where == null) ? JoinType.CrossJoin : ((join.Join == JoinType.CrossApply) ? JoinType.InnerJoin : JoinType.LeftOuter), join.Left, right, where));
}
}
}
return(join);
}
public static HashSet <TableAlias> Gather(Expression source)
{
ReferencedAliasGatherer gatherer = new ReferencedAliasGatherer();
gatherer.Visit(source);
return(gatherer.aliases);
}
private bool CanBeJoinCondition(Expression expression, HashSet <TableAlias> left, HashSet <TableAlias> right, HashSet <TableAlias> all)
{
HashSet <TableAlias> first = ReferencedAliasGatherer.Gather(expression);
bool flag = first.Intersect <TableAlias>(left).Any <TableAlias>();
bool flag2 = first.Intersect <TableAlias>(right).Any <TableAlias>();
bool flag3 = first.IsSubsetOf(all);
return((flag && flag2) && flag3);
}
private bool GetEquiJoinKeyExpressions(Expression predicate, TableAlias outerAlias, List <Expression> outerExpressions, List <Expression> innerExpressions)
{
if (predicate.NodeType == ExpressionType.Equal)
{
BinaryExpression expression = (BinaryExpression)predicate;
ColumnExpression columnExpression = this.GetColumnExpression(expression.Left);
ColumnExpression expression3 = this.GetColumnExpression(expression.Right);
if ((columnExpression != null) && (expression3 != null))
{
if (columnExpression.Alias == outerAlias)
{
outerExpressions.Add(expression.Left);
innerExpressions.Add(expression.Right);
return(true);
}
if (expression3.Alias == outerAlias)
{
innerExpressions.Add(expression.Left);
outerExpressions.Add(expression.Right);
return(true);
}
}
}
bool flag = false;
Expression[] expressionArray = predicate.Split(new ExpressionType[] { ExpressionType.And, ExpressionType.AndAlso });
if (expressionArray.Length > 1)
{
foreach (Expression expression4 in expressionArray)
{
if (ReferencedAliasGatherer.Gather(expression4).Contains(outerAlias))
{
if (!this.GetEquiJoinKeyExpressions(expression4, outerAlias, outerExpressions, innerExpressions))
{
return(false);
}
flag = true;
}
}
}
return(flag);
}
