54b06ce0f6
these searchers incorrectly called Next() on their underlying searcher, instead of Advance(). this can cause values to be returned with an ID less than the one that was Advanced() to, which violates the contract, and causes other incorrect behavior. fixes #342
126 lines
3.3 KiB
Go
126 lines
3.3 KiB
Go
// Copyright (c) 2014 Couchbase, Inc.
|
|
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
|
|
// except in compliance with the License. You may obtain a copy of the License at
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
// Unless required by applicable law or agreed to in writing, software distributed under the
|
|
// License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
|
|
// either express or implied. See the License for the specific language governing permissions
|
|
// and limitations under the License.
|
|
|
|
package searchers
|
|
|
|
import (
|
|
"github.com/blevesearch/bleve/index"
|
|
"github.com/blevesearch/bleve/search"
|
|
)
|
|
|
|
type FuzzySearcher struct {
|
|
indexReader index.IndexReader
|
|
term string
|
|
prefix int
|
|
fuzziness int
|
|
field string
|
|
explain bool
|
|
searcher *DisjunctionSearcher
|
|
}
|
|
|
|
func NewFuzzySearcher(indexReader index.IndexReader, term string, prefix, fuzziness int, field string, boost float64, explain bool) (*FuzzySearcher, error) {
|
|
prefixTerm := ""
|
|
for i, r := range term {
|
|
if i < prefix {
|
|
prefixTerm += string(r)
|
|
}
|
|
}
|
|
|
|
candidateTerms, err := findFuzzyCandidateTerms(indexReader, &term, fuzziness, field, prefixTerm)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// enumerate all the terms in the range
|
|
qsearchers := make([]search.Searcher, 0, len(candidateTerms))
|
|
|
|
for _, cterm := range candidateTerms {
|
|
qsearcher, err := NewTermSearcher(indexReader, cterm, field, boost, explain)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
qsearchers = append(qsearchers, qsearcher)
|
|
}
|
|
|
|
// build disjunction searcher of these ranges
|
|
searcher, err := NewDisjunctionSearcher(indexReader, qsearchers, 0, explain)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return &FuzzySearcher{
|
|
indexReader: indexReader,
|
|
term: term,
|
|
prefix: prefix,
|
|
fuzziness: fuzziness,
|
|
field: field,
|
|
explain: explain,
|
|
searcher: searcher,
|
|
}, nil
|
|
}
|
|
|
|
func findFuzzyCandidateTerms(indexReader index.IndexReader, term *string, fuzziness int, field, prefixTerm string) (rv []string, err error) {
|
|
rv = make([]string, 0)
|
|
var fieldDict index.FieldDict
|
|
if len(prefixTerm) > 0 {
|
|
fieldDict, err = indexReader.FieldDictPrefix(field, []byte(prefixTerm))
|
|
} else {
|
|
fieldDict, err = indexReader.FieldDict(field)
|
|
}
|
|
defer func() {
|
|
if cerr := fieldDict.Close(); cerr != nil && err == nil {
|
|
err = cerr
|
|
}
|
|
}()
|
|
|
|
// enumerate terms and check levenshtein distance
|
|
tfd, err := fieldDict.Next()
|
|
for err == nil && tfd != nil {
|
|
ld, exceeded := search.LevenshteinDistanceMax(term, &tfd.Term, fuzziness)
|
|
if !exceeded && ld <= fuzziness {
|
|
rv = append(rv, tfd.Term)
|
|
if tooManyClauses(len(rv)) {
|
|
return rv, tooManyClausesErr()
|
|
}
|
|
}
|
|
tfd, err = fieldDict.Next()
|
|
}
|
|
|
|
return rv, err
|
|
}
|
|
|
|
func (s *FuzzySearcher) Count() uint64 {
|
|
return s.searcher.Count()
|
|
}
|
|
|
|
func (s *FuzzySearcher) Weight() float64 {
|
|
return s.searcher.Weight()
|
|
}
|
|
|
|
func (s *FuzzySearcher) SetQueryNorm(qnorm float64) {
|
|
s.searcher.SetQueryNorm(qnorm)
|
|
}
|
|
|
|
func (s *FuzzySearcher) Next() (*search.DocumentMatch, error) {
|
|
return s.searcher.Next()
|
|
|
|
}
|
|
|
|
func (s *FuzzySearcher) Advance(ID string) (*search.DocumentMatch, error) {
|
|
return s.searcher.Advance(ID)
|
|
}
|
|
|
|
func (s *FuzzySearcher) Close() error {
|
|
return s.searcher.Close()
|
|
}
|
|
|
|
func (s *FuzzySearcher) Min() int {
|
|
return 0
|
|
}
|