Adding upstream version 2.5.1.

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

search/searcher/search_term_range.go

@@ -0,0 +1,92 @@
+//  Copyright (c) 2017 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 (
+	"context"
+
+	"github.com/blevesearch/bleve/v2/search"
+	index "github.com/blevesearch/bleve_index_api"
+)
+
+func NewTermRangeSearcher(ctx context.Context, indexReader index.IndexReader,
+	min, max []byte, inclusiveMin, inclusiveMax *bool, field string,
+	boost float64, options search.SearcherOptions) (search.Searcher, error) {
+
+	if inclusiveMin == nil {
+		defaultInclusiveMin := true
+		inclusiveMin = &defaultInclusiveMin
+	}
+	if inclusiveMax == nil {
+		defaultInclusiveMax := false
+		inclusiveMax = &defaultInclusiveMax
+	}
+
+	if min == nil {
+		min = []byte{}
+	}
+
+	rangeMax := max
+	if rangeMax != nil {
+		// the term dictionary range end has an unfortunate implementation
+		rangeMax = append(rangeMax, 0)
+	}
+
+	// find the terms with this prefix
+	fieldDict, err := indexReader.FieldDictRange(field, min, rangeMax)
+	if err != nil {
+		return nil, err
+	}
+
+	defer func() {
+		if cerr := fieldDict.Close(); cerr != nil && err == nil {
+			err = cerr
+		}
+	}()
+
+	var terms []string
+	tfd, err := fieldDict.Next()
+	for err == nil && tfd != nil {
+		terms = append(terms, tfd.Term)
+		tfd, err = fieldDict.Next()
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	if len(terms) < 1 {
+		return NewMatchNoneSearcher(indexReader)
+	}
+
+	if !*inclusiveMin && min != nil && string(min) == terms[0] {
+		terms = terms[1:]
+		// check again, as we might have removed only entry
+		if len(terms) < 1 {
+			return NewMatchNoneSearcher(indexReader)
+		}
+	}
+
+	// if our term list included the max, it would be the last item
+	if !*inclusiveMax && max != nil && string(max) == terms[len(terms)-1] {
+		terms = terms[:len(terms)-1]
+	}
+
+	if ctx != nil {
+		reportIOStats(ctx, fieldDict.BytesRead())
+		search.RecordSearchCost(ctx, search.AddM, fieldDict.BytesRead())
+	}
+
+	return NewMultiTermSearcher(ctx, indexReader, terms, field, boost, options, true)
+}