private Func <T, bool> GenerateInFilterFunction <T>(InFilterNode node, BaseFilterOperation <T> filterOperation, QueryEngine <T> engine, ICollection <QueryError> errors)
{
if (node.leaf || node.children == null || node.children.Count == 0)
{
errors.Add(new QueryError(node.token.position, "InFilter node cannot be a leaf."));
return(null);
}
var nestedQueryType = GetNestedQueryType(node);
if (nestedQueryType == null)
{
errors.Add(new QueryError(node.token.position, "Could not deduce nested query type. Did you forget to set the nested query handler?"));
return(null);
}
var transformType = node.filter.queryHandlerTransformer.rightHandSideType;
var inFilterFunc = typeof(WhereEnumerableFactory)
?.GetMethod("GenerateInFilterFunctionWithTypes", BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.Instance)
?.MakeGenericMethod(typeof(T), nestedQueryType, transformType)
?.Invoke(this, new object[] { node, filterOperation, engine, errors }) as Func <T, bool>;
if (inFilterFunc == null)
{
errors.Add(new QueryError(node.token.position, "Could not create filter function with nested query."));
return(null);
}
return(inFilterFunc);
}
private Func <T, bool> GenerateInFilterFunctionWithTypes <T, TNested, TTransform>(InFilterNode node, BaseFilterOperation <T> filterOperation, QueryEngine <T> engine, ICollection <QueryError> errors)
{
var nestedQueryEnumerable = EnumerableCreator.Create <TNested>(node.children[0], null, errors);
if (nestedQueryEnumerable == null)
{
return(null);
}
var nestedQueryTransformer = node.filter.queryHandlerTransformer as NestedQueryHandlerTransformer <TNested, TTransform>;
if (nestedQueryTransformer == null)
{
return(null);
}
var transformerFunction = nestedQueryTransformer.handler;
var dynamicFilterOperation = filterOperation as IDynamicFilterOperation <TTransform>;
if (dynamicFilterOperation == null)
{
return(null);
}
return(o =>
{
foreach (var item in nestedQueryEnumerable)
{
var transformedValue = transformerFunction(item);
dynamicFilterOperation.SetFilterValue(transformedValue);
if (filterOperation.Match(o))
{
return true;
}
}
return false;
});
}