/// <summary>
/// Finds objects matching filter conditions in <paramref name="Where"/>.
/// </summary>
/// <param name="Offset">Offset at which to return elements.</param>
/// <param name="Top">Maximum number of elements to return.</param>
/// <param name="Where">Filter conditions.</param>
/// <param name="Variables">Current set of variables.</param>
/// <param name="Order">Order at which to order the result set.</param>
/// <param name="Node">Script node performing the evaluation.</param>
/// <returns>Enumerator.</returns>
public override async Task <IResultSetEnumerator> Find(int Offset, int Top, ScriptNode Where, Variables Variables,
KeyValuePair <VariableReference, bool>[] Order, ScriptNode Node)
{
ScriptNode LeftWhere = await Reduce(this.Left, Where);
KeyValuePair <VariableReference, bool>[] LeftOrder = await Reduce(this.Left, Order);
IResultSetEnumerator e = await this.Left.Find(0, int.MaxValue,
LeftWhere, Variables, LeftOrder, Node);
ScriptNode RightWhere = this.Combine(await Reduce(this.Right, this.Left, Where), this.Conditions);
e = new LeftOuterJoinEnumerator(e, this.Left.Name, this.Right, this.Right.Name,
RightWhere, Variables, this.Flipped);
if (!(Where is null))
{
e = new ConditionalEnumerator(e, Variables, Where);
}
if (Offset > 0)
{
e = new OffsetEnumerator(e, Offset);
}
if (Top != int.MaxValue)
{
e = new MaxCountEnumerator(e, Top);
}
return(e);
}
/// <summary>
/// Finds objects matching filter conditions in <paramref name="Where"/>.
/// </summary>
/// <param name="Offset">Offset at which to return elements.</param>
/// <param name="Top">Maximum number of elements to return.</param>
/// <param name="Where">Filter conditions.</param>
/// <param name="Variables">Current set of variables.</param>
/// <param name="Order">Order at which to order the result set.</param>
/// <param name="Node">Script node performing the evaluation.</param>
/// <returns>Enumerator.</returns>
public async Task <IResultSetEnumerator> Find(int Offset, int Top, ScriptNode Where, Variables Variables,
KeyValuePair <VariableReference, bool>[] Order, ScriptNode Node)
{
IResultSetEnumerator e = new SynchEnumerator(this.vector.VectorElements.GetEnumerator());
int i, c;
if (Where != null)
{
e = new ConditionalEnumerator(e, Variables, Where);
}
if ((c = Order?.Length ?? 0) > 0)
{
List <IElement> Items = new List <IElement>();
while (await e.MoveNextAsync())
{
if (e.Current is Element E)
{
Items.Add(E);
}
else
{
Items.Add(Expression.Encapsulate(e.Current));
}
}
Items.Add(e.Current as IElement);
IComparer <IElement> Order2;
if (c == 1)
{
Order2 = ToPropertyOrder(Node, Order[0]);
}
else
{
IComparer <IElement>[] Orders = new IComparer <IElement> [c];
for (i = 0; i < c; i++)
{
Orders[i] = ToPropertyOrder(Node, Order[i]);
}
Order2 = new CompoundOrder(Orders);
}
Items.Sort(Order2);
e = new SynchEnumerator(Items.GetEnumerator());
}
if (Offset > 0)
{
e = new OffsetEnumerator(e, Offset);
}
if (Top != int.MaxValue)
{
e = new MaxCountEnumerator(e, Top);
}
return(e);
}
