// BuildNodeIterator returns an iterator for retrieving the results of the query, with
// each result being a struct representing the node and the values found outgoing at the
// given predicates.
func (gq GraphQuery) BuildNodeIterator(predicates ...Predicate) NodeIterator {
if (gq.singleDirection == 1 || gq.singleDirection == -1) && gq.singleStartingValue != nil &&
gq.singlePredicate != nil && len(predicates) == 0 {
// Special case: An iterator from a single starting node in a single direction over
// a single predicate with no custom values.
return newSimpleDirectionalIterator(gq.layer, gq.singleStartingValue, gq.singlePredicate, gq.singleDirection)
}
var updatedPath *path.Path = gq.path
// Save the predicates the user requested.
for _, predicate := range predicates {
fullPredicate := gq.layer.getPrefixedPredicate(predicate)
updatedPath = updatedPath.Save(fullPredicate, valueToPredicateString(fullPredicate))
}
// Save the predicate for the kind of the node as well.
fullKindPredicate := gq.layer.getPrefixedPredicate(gq.layer.nodeKindPredicate)
updatedPath = updatedPath.Save(fullKindPredicate, valueToPredicateString(fullKindPredicate))
it := updatedPath.BuildIterator()
oit, _ := it.Optimize()
return &graphNodeIterator{
layer: gq.layer,
iterator: oit,
tagCount: gq.tagCount + 1 + len(predicates), // +1 for kind.
}
}
func buildPathFromObject(obj *otto.Object) *path.Path {
var p *path.Path
val, _ := obj.Get("_gremlin_type")
stringArgs := propertiesOf(obj, "string_args")
gremlinType := val.String()
if prev, _ := obj.Get("_gremlin_prev"); !prev.IsObject() {
switch gremlinType {
case "vertex":
return path.StartMorphism(stringArgs...)
case "morphism":
return path.StartMorphism()
default:
panic("No base gremlin path other than 'vertex' or 'morphism'")
}
} else {
p = buildPathFromObject(prev.Object())
}
if p == nil {
return nil
}
switch gremlinType {
case "Is":
return p.Is(stringArgs...)
case "In":
preds, tags, ok := getViaData(obj)
if !ok {
return nil
}
return p.InWithTags(tags, preds...)
case "Out":
preds, tags, ok := getViaData(obj)
if !ok {
return nil
}
return p.OutWithTags(tags, preds...)
case "Both":
preds, _, ok := getViaData(obj)
if !ok {
return nil
}
return p.Both(preds...)
case "Follow":
subobj := getFirstArgAsMorphismChain(obj)
if subobj == nil {
return nil
}
return p.Follow(buildPathFromObject(subobj))
case "FollowR":
subobj := getFirstArgAsMorphismChain(obj)
if subobj == nil {
return nil
}
return p.FollowReverse(buildPathFromObject(subobj))
case "And", "Intersect":
subobj := getFirstArgAsVertexChain(obj)
if subobj == nil {
return nil
}
return p.And(buildPathFromObject(subobj))
case "Union", "Or":
subobj := getFirstArgAsVertexChain(obj)
if subobj == nil {
return nil
}
return p.Or(buildPathFromObject(subobj))
case "Back":
if len(stringArgs) != 1 {
return nil
}
return p.Back(stringArgs[0])
case "Tag", "As":
return p.Tag(stringArgs...)
case "Has":
if len(stringArgs) < 2 {
return nil
}
return p.Has(stringArgs[0], stringArgs[1:]...)
case "Save", "SaveR":
if len(stringArgs) > 2 || len(stringArgs) == 0 {
return nil
}
tag := stringArgs[0]
if len(stringArgs) == 2 {
tag = stringArgs[1]
}
if gremlinType == "SaveR" {
return p.SaveReverse(stringArgs[0], tag)
}
return p.Save(stringArgs[0], tag)
case "Except", "Difference":
subobj := getFirstArgAsVertexChain(obj)
if subobj == nil {
return nil
}
return p.Except(buildPathFromObject(subobj))
case "InPredicates":
return p.InPredicates()
case "OutPredicates":
return p.OutPredicates()
case "LabelContext":
labels, tags, ok := getViaData(obj)
if !ok {
return nil
}
return p.LabelContextWithTags(tags, labels...)
default:
panic(fmt.Sprint("Unimplemented Gremlin function", gremlinType))
}
}