gitroast/vendor/github.com/blevesearch/bleve/search/searcher/search_regexp.go

93 lines
2.5 KiB
Go

// Copyright (c) 2015 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 searcher
import (
"regexp"
"github.com/blevesearch/bleve/index"
"github.com/blevesearch/bleve/search"
)
func NewRegexpSearcher(indexReader index.IndexReader, pattern *regexp.Regexp, field string, boost float64, explain bool) (search.Searcher, error) {
prefixTerm, complete := pattern.LiteralPrefix()
var candidateTerms []string
if complete {
// there is no pattern
candidateTerms = []string{prefixTerm}
} else {
var err error
candidateTerms, err = findRegexpCandidateTerms(indexReader, pattern, field, prefixTerm)
if err != nil {
return nil, err
}
}
// enumerate all the terms in the range
qsearchers := make([]search.Searcher, 0, len(candidateTerms))
qsearchersClose := func() {
for _, searcher := range qsearchers {
_ = searcher.Close()
}
}
for _, cterm := range candidateTerms {
qsearcher, err := NewTermSearcher(indexReader, cterm, field, boost, explain)
if err != nil {
qsearchersClose()
return nil, err
}
qsearchers = append(qsearchers, qsearcher)
}
// build disjunction searcher of these ranges
searcher, err := NewDisjunctionSearcher(indexReader, qsearchers, 0, explain)
if err != nil {
qsearchersClose()
return nil, err
}
return searcher, err
}
func findRegexpCandidateTerms(indexReader index.IndexReader, pattern *regexp.Regexp, 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 the terms and check against regexp
tfd, err := fieldDict.Next()
for err == nil && tfd != nil {
if pattern.MatchString(tfd.Term) {
rv = append(rv, tfd.Term)
if tooManyClauses(len(rv)) {
return rv, tooManyClausesErr()
}
}
tfd, err = fieldDict.Next()
}
return rv, err
}