func (qs *QuadStore) optimizeLinksTo(it *iterator.LinksTo) (graph.Iterator, bool) {
subs := it.SubIterators()
if len(subs) != 1 {
return it, false
}
primary := subs[0]
if primary.Type() == graph.Fixed {
size, _ := primary.Size()
if size == 1 {
if !primary.Next() {
panic("unexpected size during optimize")
}
val := primary.Result()
newIt := qs.QuadIterator(it.Direction(), val)
nt := newIt.Tagger()
nt.CopyFrom(it)
for _, tag := range primary.Tagger().Tags() {
nt.AddFixed(tag, val)
}
it.Close()
return newIt, true
}
}
return it, false
}
func (qs *QuadStore) optimizeLinksTo(it *iterator.LinksTo) (graph.Iterator, bool) {
subs := it.SubIterators()
if len(subs) != 1 {
return it, false
}
primary := subs[0]
switch primary.Type() {
case graph.Fixed:
size, _ := primary.Size()
if size == 0 {
return iterator.NewNull(), true
}
if size == 1 {
if !primary.Next() {
panic("sql: unexpected size during optimize")
}
val := primary.Result()
newIt := qs.QuadIterator(it.Direction(), val)
nt := newIt.Tagger()
nt.CopyFrom(it)
for _, tag := range primary.Tagger().Tags() {
nt.AddFixed(tag, val)
}
it.Close()
return newIt, true
} else if size > 1 {
var vals []NodeHash
for primary.Next() {
vals = append(vals, primary.Result().(NodeHash))
}
lsql := &SQLLinkIterator{
constraints: []constraint{
constraint{
dir: it.Direction(),
hashes: vals,
},
},
tableName: newTableName(),
size: 0,
}
l := &SQLIterator{
uid: iterator.NextUID(),
qs: qs,
sql: lsql,
}
nt := l.Tagger()
nt.CopyFrom(it)
for _, t := range primary.Tagger().Tags() {
lsql.tagdirs = append(lsql.tagdirs, tagDir{
dir: it.Direction(),
tag: t,
})
}
it.Close()
return l, true
}
case sqlType:
p := primary.(*SQLIterator)
newit, err := linksto(p.sql, it.Direction(), qs)
if err != nil {
clog.Errorf("%v", err)
return it, false
}
newit.Tagger().CopyFrom(it)
return newit, true
case graph.All:
linkit := &SQLLinkIterator{
tableName: newTableName(),
size: qs.Size(),
}
for _, t := range primary.Tagger().Tags() {
linkit.tagdirs = append(linkit.tagdirs, tagDir{
dir: it.Direction(),
tag: t,
})
}
for k, v := range primary.Tagger().Fixed() {
linkit.tagger.AddFixed(k, v)
}
linkit.tagger.CopyFrom(it)
newit := NewSQLIterator(qs, linkit)
return newit, true
}
return it, false
}