93 lines
2.5 KiB
Go
93 lines
2.5 KiB
Go
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// Copyright (c) 2015 Couchbase, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package searcher
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import (
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"regexp"
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"github.com/blevesearch/bleve/index"
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"github.com/blevesearch/bleve/search"
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)
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func NewRegexpSearcher(indexReader index.IndexReader, pattern *regexp.Regexp, field string, boost float64, explain bool) (search.Searcher, error) {
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prefixTerm, complete := pattern.LiteralPrefix()
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var candidateTerms []string
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if complete {
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// there is no pattern
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candidateTerms = []string{prefixTerm}
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} else {
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var err error
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candidateTerms, err = findRegexpCandidateTerms(indexReader, pattern, field, prefixTerm)
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if err != nil {
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return nil, err
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}
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}
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// enumerate all the terms in the range
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qsearchers := make([]search.Searcher, 0, len(candidateTerms))
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qsearchersClose := func() {
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for _, searcher := range qsearchers {
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_ = searcher.Close()
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}
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}
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for _, cterm := range candidateTerms {
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qsearcher, err := NewTermSearcher(indexReader, cterm, field, boost, explain)
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if err != nil {
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qsearchersClose()
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return nil, err
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}
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qsearchers = append(qsearchers, qsearcher)
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}
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// build disjunction searcher of these ranges
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searcher, err := NewDisjunctionSearcher(indexReader, qsearchers, 0, explain)
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if err != nil {
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qsearchersClose()
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return nil, err
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}
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return searcher, err
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}
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func findRegexpCandidateTerms(indexReader index.IndexReader, pattern *regexp.Regexp, field, prefixTerm string) (rv []string, err error) {
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rv = make([]string, 0)
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var fieldDict index.FieldDict
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if len(prefixTerm) > 0 {
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fieldDict, err = indexReader.FieldDictPrefix(field, []byte(prefixTerm))
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} else {
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fieldDict, err = indexReader.FieldDict(field)
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}
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defer func() {
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if cerr := fieldDict.Close(); cerr != nil && err == nil {
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err = cerr
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}
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}()
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// enumerate the terms and check against regexp
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tfd, err := fieldDict.Next()
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for err == nil && tfd != nil {
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if pattern.MatchString(tfd.Term) {
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rv = append(rv, tfd.Term)
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if tooManyClauses(len(rv)) {
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return rv, tooManyClausesErr()
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}
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}
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tfd, err = fieldDict.Next()
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}
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return rv, err
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}
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