Search bar for issues/pulls (#530)

vendor/github.com/blevesearch/bleve/search/query/match.go

@@ -0,0 +1,176 @@
+//  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 (
+	"encoding/json"
+	"fmt"
+
+	"github.com/blevesearch/bleve/index"
+	"github.com/blevesearch/bleve/mapping"
+	"github.com/blevesearch/bleve/search"
+)
+
+type MatchQuery struct {
+	Match     string             `json:"match"`
+	FieldVal  string             `json:"field,omitempty"`
+	Analyzer  string             `json:"analyzer,omitempty"`
+	BoostVal  *Boost             `json:"boost,omitempty"`
+	Prefix    int                `json:"prefix_length"`
+	Fuzziness int                `json:"fuzziness"`
+	Operator  MatchQueryOperator `json:"operator,omitempty"`
+}
+
+type MatchQueryOperator int
+
+const (
+	// Document must satisfy AT LEAST ONE of term searches.
+	MatchQueryOperatorOr = 0
+	// Document must satisfy ALL of term searches.
+	MatchQueryOperatorAnd = 1
+)
+
+func (o MatchQueryOperator) MarshalJSON() ([]byte, error) {
+	switch o {
+	case MatchQueryOperatorOr:
+		return json.Marshal("or")
+	case MatchQueryOperatorAnd:
+		return json.Marshal("and")
+	default:
+		return nil, fmt.Errorf("cannot marshal match operator %d to JSON", o)
+	}
+}
+
+func (o *MatchQueryOperator) UnmarshalJSON(data []byte) error {
+	var operatorString string
+	err := json.Unmarshal(data, &operatorString)
+	if err != nil {
+		return err
+	}
+
+	switch operatorString {
+	case "or":
+		*o = MatchQueryOperatorOr
+		return nil
+	case "and":
+		*o = MatchQueryOperatorAnd
+		return nil
+	default:
+		return fmt.Errorf("cannot unmarshal match operator '%v' from JSON", o)
+	}
+}
+
+// NewMatchQuery creates a Query for matching text.
+// An Analyzer is chosen based on the field.
+// Input text is analyzed using this analyzer.
+// Token terms resulting from this analysis are
+// used to perform term searches.  Result documents
+// must satisfy at least one of these term searches.
+func NewMatchQuery(match string) *MatchQuery {
+	return &MatchQuery{
+		Match:    match,
+		Operator: MatchQueryOperatorOr,
+	}
+}
+
+func (q *MatchQuery) SetBoost(b float64) {
+	boost := Boost(b)
+	q.BoostVal = &boost
+}
+
+func (q *MatchQuery) Boost() float64{
+	return q.BoostVal.Value()
+}
+
+func (q *MatchQuery) SetField(f string) {
+	q.FieldVal = f
+}
+
+func (q *MatchQuery) Field() string{
+	return q.FieldVal
+}
+
+func (q *MatchQuery) SetFuzziness(f int) {
+	q.Fuzziness = f
+}
+
+func (q *MatchQuery) SetPrefix(p int) {
+	q.Prefix = p
+}
+
+func (q *MatchQuery) SetOperator(operator MatchQueryOperator) {
+	q.Operator = operator
+}
+
+func (q *MatchQuery) Searcher(i index.IndexReader, m mapping.IndexMapping, explain bool) (search.Searcher, error) {
+
+	field := q.FieldVal
+	if q.FieldVal == "" {
+		field = m.DefaultSearchField()
+	}
+
+	analyzerName := ""
+	if q.Analyzer != "" {
+		analyzerName = q.Analyzer
+	} else {
+		analyzerName = m.AnalyzerNameForPath(field)
+	}
+	analyzer := m.AnalyzerNamed(analyzerName)
+
+	if analyzer == nil {
+		return nil, fmt.Errorf("no analyzer named '%s' registered", q.Analyzer)
+	}
+
+	tokens := analyzer.Analyze([]byte(q.Match))
+	if len(tokens) > 0 {
+
+		tqs := make([]Query, len(tokens))
+		if q.Fuzziness != 0 {
+			for i, token := range tokens {
+				query := NewFuzzyQuery(string(token.Term))
+				query.SetFuzziness(q.Fuzziness)
+				query.SetPrefix(q.Prefix)
+				query.SetField(field)
+				query.SetBoost(q.BoostVal.Value())
+				tqs[i] = query
+			}
+		} else {
+			for i, token := range tokens {
+				tq := NewTermQuery(string(token.Term))
+				tq.SetField(field)
+				tq.SetBoost(q.BoostVal.Value())
+				tqs[i] = tq
+			}
+		}
+
+		switch q.Operator {
+		case MatchQueryOperatorOr:
+			shouldQuery := NewDisjunctionQuery(tqs)
+			shouldQuery.SetMin(1)
+			shouldQuery.SetBoost(q.BoostVal.Value())
+			return shouldQuery.Searcher(i, m, explain)
+
+		case MatchQueryOperatorAnd:
+			mustQuery := NewConjunctionQuery(tqs)
+			mustQuery.SetBoost(q.BoostVal.Value())
+			return mustQuery.Searcher(i, m, explain)
+
+		default:
+			return nil, fmt.Errorf("unhandled operator %d", q.Operator)
+		}
+	}
+	noneQuery := NewMatchNoneQuery()
+	return noneQuery.Searcher(i, m, explain)
+}