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* This file is available under the Apache License, Version 2.0,
* with the Commons Clause restriction.
*/
package worker
import (
"errors"
cindex "github.com/google/codesearch/index"
"github.com/dgraph-io/dgraph/algo"
"github.com/dgraph-io/dgraph/posting"
"github.com/dgraph-io/dgraph/protos/intern"
"github.com/dgraph-io/dgraph/tok"
"github.com/dgraph-io/dgraph/x"
)
var regexTooWideErr = errors.New("Regular expression is too wide-ranging and can't be executed efficiently.")
func uidsForRegex(attr string, arg funcArgs,
query *cindex.Query, intersect *intern.List) (*intern.List, error) {
var results *intern.List
opts := posting.ListOptions{
ReadTs: arg.q.ReadTs,
}
if intersect.Size() > 0 {
opts.Intersect = intersect
}
uidsForTrigram := func(trigram string) (*intern.List, error) {
key := x.IndexKey(attr, trigram)
pl, err := posting.Get(key)
if err != nil {
return nil, err
}
return pl.Uids(opts)
}
switch query.Op {
case cindex.QAnd:
tok.EncodeRegexTokens(query.Trigram)
for _, t := range query.Trigram {
trigramUids, err := uidsForTrigram(t)
if err != nil {
return nil, err
}
if results == nil {
results = trigramUids
} else {
algo.IntersectWith(results, trigramUids, results)
}
if results.Size() == 0 {
return results, nil
}
}
for _, sub := range query.Sub {
if results == nil {
results = intersect
}
// current list of result is passed for intersection
results, err = uidsForRegex(attr, arg, sub, results)
if err != nil {
return nil, err
}
if results.Size() == 0 {
return results, nil
}
}
case cindex.QOr:
tok.EncodeRegexTokens(query.Trigram)
uidMatrix := make([]*intern.List, len(query.Trigram))
for i, t := range query.Trigram {
uidMatrix[i], err = uidsForTrigram(t)
if err != nil {
return nil, err
}
}
results = algo.MergeSorted(uidMatrix)
for _, sub := range query.Sub {
if results == nil {
results = intersect
}
subUids, err := uidsForRegex(attr, arg, sub, intersect)
if err != nil {
return nil, err
}
results = algo.MergeSorted([]*intern.List{results, subUids})
}
default:
return nil, regexTooWideErr
}
return results, nil
}