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Added comments for the not operator.

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This commit is contained in:
Matei Chiperi 2014-08-26 11:59:14 -07:00
parent d3bc8c1736
commit d9b67c8335
2 changed files with 14 additions and 5 deletions
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10
graph/iterator/not_iterator.go
View file

@ -2,6 +2,8 @@ package iterator
import "github.com/google/cayley/graph"
// Not iterator acts like a set difference between the primary iterator
// and the forbidden iterator.
type Not struct {
uid uint64
tags graph.Tagger
@ -33,6 +35,7 @@ func (it *Not) Tagger() *graph.Tagger {
return &it.tags
}
// TODO
func (it *Not) TagResults(dst map[string]graph.Value) {
for _, tag := range it.tags.Tags() {
dst[tag] = it.Result()
@ -45,8 +48,6 @@ func (it *Not) TagResults(dst map[string]graph.Value) {
if it.primaryIt != nil {
it.primaryIt.TagResults(dst)
}
// todo
}
func (it *Not) Clone() graph.Iterator {
@ -73,7 +74,10 @@ func (it *Not) DebugString(indent int) string {
func (it *Not) Next() bool {
graph.NextLogIn(it)
it.runstats.Next += 1
for graph.Next(it.primaryIt) {
// Consider only the elements from the primary set which are not
// contained in the forbidden set.
if curr := it.primaryIt.Result(); !it.forbiddenIt.Contains(curr) {
it.result = curr
it.runstats.ContainsNext += 1
@ -112,11 +116,13 @@ func (it *Not) Close() {
func (it *Not) Type() graph.Type { return graph.Not }
// TODO
func (it *Not) Optimize() (graph.Iterator, bool) {
//it.forbiddenIt = NewMaterialize(it.forbiddenIt)
return it, false
}
// TODO
func (it *Not) Stats() graph.IteratorStats {
subitStats := it.primaryIt.Stats()
// TODO(barakmich): These should really come from the triplestore itself

9
query/gremlin/build_iterator.go
View file

@ -300,21 +300,24 @@ func buildIteratorTreeHelper(obj *otto.Object, ts graph.TripleStore, base graph.
it = buildInOutIterator(obj, ts, subIt, true)
case "not":
// Not is implemented as the difference between the primary iterator
// and the iterator chain of (primaryIt, follow, followR).
// Build the follow iterator
// and the iterator chain composed of (primaryIt->Follow->FollowR).
// Arguments for follow iterator
arg, _ := obj.Get("_gremlin_values")
firstArg, _ := arg.Object().Get("0")
if isVertexChain(firstArg.Object()) {
return iterator.NewNull()
}
// Build the followR iterator
// Arguments for followR iterator
revArg, _ := obj.Get("_gremlin_followr")
if isVertexChain(revArg.Object()) {
return iterator.NewNull()
}
// Build the primaryIt->Follow iterator
followIt := buildIteratorTreeHelper(firstArg.Object(), ts, subIt)
// Build the primaryIt->Follow->FollowR iterator
forbiddenIt := buildIteratorTreeHelper(revArg.Object(), ts, followIt)
it = iterator.NewNot(subIt, forbiddenIt)