Search: Add substring matcher (#54895)

* Search: Add substring matcher (#54813) * search: bring back substring search * lint fix * search: bring back ngram * search: bring back ngram * search: more tests * fix tests
2022-09-09 14:20:20 +02:00
parent 19a58da54c
commit e1f5d698e6
11 changed files with 662 additions and 74 deletions
@@ -0,0 +1,102 @@
+// based on https://github.com/blugelabs/bluge/blob/57414197005148539c5dc5db8ab581594969df79/query.go#L1407-L1482, license:
+// Copyright (c) 2020 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 searchV2
+
+import (
+	"strings"
+
+	"github.com/blugelabs/bluge/search"
+	"github.com/blugelabs/bluge/search/searcher"
+	"github.com/blugelabs/bluge/search/similarity"
+)
+
+type boost float64
+
+func (b *boost) Value() float64 {
+	if b == nil {
+		return 1
+	}
+	return float64(*b)
+}
+
+type SubstringQuery struct {
+	substring string
+	field     string
+	boost     *boost
+	scorer    search.Scorer
+}
+
+func NewSubstringQuery(wildcard string) *SubstringQuery {
+	return &SubstringQuery{
+		substring: wildcard,
+	}
+}
+
+// Wildcard returns the substring being queried
+func (q *SubstringQuery) Wildcard() string {
+	return q.substring
+}
+
+func (q *SubstringQuery) SetBoost(b float64) *SubstringQuery {
+	boostVal := boost(b)
+	q.boost = &boostVal
+	return q
+}
+
+func (q *SubstringQuery) Boost() float64 {
+	return q.boost.Value()
+}
+
+func (q *SubstringQuery) SetField(f string) *SubstringQuery {
+	q.field = f
+	return q
+}
+
+func (q *SubstringQuery) Field() string {
+	return q.field
+}
+
+var regexpEscaper = strings.NewReplacer(
+	// characters in the substring that must
+	// be escaped in the regexp
+	"+", `\+`,
+	"*", `\*`,
+	"(", `\(`,
+	")", `\)`,
+	"^", `\^`,
+	"$", `\$`,
+	".", `\.`,
+	"{", `\{`,
+	"}", `\}`,
+	"[", `\[`,
+	"]", `\]`,
+	`|`, `\|`,
+	`\`, `\\`)
+
+func (q *SubstringQuery) Searcher(i search.Reader, options search.SearcherOptions) (search.Searcher, error) {
+	field := q.field
+	if q.field == "" {
+		field = options.DefaultSearchField
+	}
+
+	regexpString := ".*" + regexpEscaper.Replace(q.substring) + ".*"
+	return searcher.NewRegexpStringSearcher(i, regexpString, field,
+		q.boost.Value(), q.scorer, similarity.NewCompositeSumScorer(), options)
+}
+
+func (q *SubstringQuery) Validate() error {
+	return nil // real validation delayed until searcher constructor
+}