Adding upstream version 2.5.1.

Signed-off-by: Daniel Baumann <daniel@debian.org>

search/query/fuzzy.go

@@ -0,0 +1,134 @@
+//  Copyright (c) 2014 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 query
+
+import (
+	"context"
+
+	"github.com/blevesearch/bleve/v2/mapping"
+	"github.com/blevesearch/bleve/v2/search"
+	"github.com/blevesearch/bleve/v2/search/searcher"
+	"github.com/blevesearch/bleve/v2/util"
+	index "github.com/blevesearch/bleve_index_api"
+)
+
+type FuzzyQuery struct {
+	Term      string `json:"term"`
+	Prefix    int    `json:"prefix_length"`
+	Fuzziness int    `json:"fuzziness"`
+	FieldVal  string `json:"field,omitempty"`
+	BoostVal  *Boost `json:"boost,omitempty"`
+	autoFuzzy bool
+}
+
+// NewFuzzyQuery creates a new Query which finds
+// documents containing terms within a specific
+// fuzziness of the specified term.
+// The default fuzziness is 1.
+//
+// The current implementation uses Levenshtein edit
+// distance as the fuzziness metric.
+func NewFuzzyQuery(term string) *FuzzyQuery {
+	return &FuzzyQuery{
+		Term:      term,
+		Fuzziness: 1,
+	}
+}
+
+func (q *FuzzyQuery) SetBoost(b float64) {
+	boost := Boost(b)
+	q.BoostVal = &boost
+}
+
+func (q *FuzzyQuery) Boost() float64 {
+	return q.BoostVal.Value()
+}
+
+func (q *FuzzyQuery) SetField(f string) {
+	q.FieldVal = f
+}
+
+func (q *FuzzyQuery) Field() string {
+	return q.FieldVal
+}
+
+func (q *FuzzyQuery) SetFuzziness(f int) {
+	q.Fuzziness = f
+}
+
+func (q *FuzzyQuery) SetAutoFuzziness(a bool) {
+	q.autoFuzzy = a
+}
+
+func (q *FuzzyQuery) SetPrefix(p int) {
+	q.Prefix = p
+}
+
+func (q *FuzzyQuery) Searcher(ctx context.Context, i index.IndexReader, m mapping.IndexMapping, options search.SearcherOptions) (search.Searcher, error) {
+	field := q.FieldVal
+	if q.FieldVal == "" {
+		field = m.DefaultSearchField()
+	}
+	if q.autoFuzzy {
+		return searcher.NewAutoFuzzySearcher(ctx, i, q.Term, q.Prefix, field, q.BoostVal.Value(), options)
+	}
+	return searcher.NewFuzzySearcher(ctx, i, q.Term, q.Prefix, q.Fuzziness, field, q.BoostVal.Value(), options)
+}
+
+func (q *FuzzyQuery) UnmarshalJSON(data []byte) error {
+	type Alias FuzzyQuery
+	aux := &struct {
+		Fuzziness interface{} `json:"fuzziness"`
+		*Alias
+	}{
+		Alias: (*Alias)(q),
+	}
+	if err := util.UnmarshalJSON(data, &aux); err != nil {
+		return err
+	}
+	switch v := aux.Fuzziness.(type) {
+	case float64:
+		q.Fuzziness = int(v)
+	case string:
+		if v == "auto" {
+			q.autoFuzzy = true
+		}
+	}
+	return nil
+}
+
+func (f *FuzzyQuery) MarshalJSON() ([]byte, error) {
+	var fuzzyValue interface{}
+	if f.autoFuzzy {
+		fuzzyValue = "auto"
+	} else {
+		fuzzyValue = f.Fuzziness
+	}
+	type fuzzyQuery struct {
+		Term      string      `json:"term"`
+		Prefix    int         `json:"prefix_length"`
+		Fuzziness interface{} `json:"fuzziness"`
+		FieldVal  string      `json:"field,omitempty"`
+		BoostVal  *Boost      `json:"boost,omitempty"`
+	}
+	aux := fuzzyQuery{
+		Term:      f.Term,
+		Prefix:    f.Prefix,
+		Fuzziness: fuzzyValue,
+		FieldVal:  f.FieldVal,
+		BoostVal:  f.BoostVal,
+	}
+	return util.MarshalJSON(aux)
+}