forked from blevesearch/bleve
/
search_regexp.go
128 lines (106 loc) · 3.39 KB
/
search_regexp.go
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// 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 searchers
import (
"regexp"
"github.com/blevesearch/bleve/index"
"github.com/blevesearch/bleve/search"
)
type RegexpSearcher struct {
indexReader index.IndexReader
pattern *regexp.Regexp
field string
explain bool
searcher *DisjunctionSearcher
}
func NewRegexpSearcher(indexReader index.IndexReader, pattern *regexp.Regexp, field string, boost float64, explain bool) (*RegexpSearcher, 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))
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 &RegexpSearcher{
indexReader: indexReader,
pattern: pattern,
field: field,
explain: explain,
searcher: searcher,
}, nil
}
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
}
func (s *RegexpSearcher) Count() uint64 {
return s.searcher.Count()
}
func (s *RegexpSearcher) Weight() float64 {
return s.searcher.Weight()
}
func (s *RegexpSearcher) SetQueryNorm(qnorm float64) {
s.searcher.SetQueryNorm(qnorm)
}
func (s *RegexpSearcher) Next(ctx *search.SearchContext) (*search.DocumentMatch, error) {
return s.searcher.Next(ctx)
}
func (s *RegexpSearcher) Advance(ctx *search.SearchContext, ID index.IndexInternalID) (*search.DocumentMatch, error) {
return s.searcher.Advance(ctx, ID)
}
func (s *RegexpSearcher) Close() error {
return s.searcher.Close()
}
func (s *RegexpSearcher) Min() int {
return 0
}
func (s *RegexpSearcher) DocumentMatchPoolSize() int {
return s.searcher.DocumentMatchPoolSize()
}