Search bar for issues/pulls (#530)

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

@@ -0,0 +1,92 @@
+//  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
+}