func (qs *QuadStore) QuadIterator(d quad.Direction, val graph.Value) graph.Iterator {
var prefix string
switch d {
case quad.Subject:
prefix = "sp"
case quad.Predicate:
prefix = "po"
case quad.Object:
prefix = "os"
case quad.Label:
prefix = "cp"
default:
panic("unreachable " + d.String())
}
return NewIterator(prefix, d, val, qs)
}
func NewIterator(qs *QuadStore, collection string, d quad.Direction, val graph.Value) *Iterator {
name := qs.NameOf(val)
constraint := bson.M{d.String(): name}
return &Iterator{
uid: iterator.NextUID(),
name: name,
constraint: constraint,
collection: collection,
qs: qs,
dir: d,
iter: nil,
size: -1,
hash: val.(string),
isAll: false,
}
}