Adding upstream version 2.5.1.

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

search/searcher/search_knn.go

@@ -0,0 +1,145 @@
+//  Copyright (c) 2023 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.
+
+//go:build vectors
+// +build vectors
+
+package searcher
+
+import (
+	"context"
+	"encoding/json"
+	"reflect"
+
+	"github.com/blevesearch/bleve/v2/mapping"
+	"github.com/blevesearch/bleve/v2/search"
+	"github.com/blevesearch/bleve/v2/search/scorer"
+	"github.com/blevesearch/bleve/v2/size"
+	index "github.com/blevesearch/bleve_index_api"
+)
+
+var reflectStaticSizeKNNSearcher int
+
+func init() {
+	var ks KNNSearcher
+	reflectStaticSizeKNNSearcher = int(reflect.TypeOf(ks).Size())
+}
+
+type KNNSearcher struct {
+	field        string
+	vector       []float32
+	k            int64
+	indexReader  index.IndexReader
+	vectorReader index.VectorReader
+	scorer       *scorer.KNNQueryScorer
+	count        uint64
+	vd           index.VectorDoc
+}
+
+func NewKNNSearcher(ctx context.Context, i index.IndexReader, m mapping.IndexMapping,
+	options search.SearcherOptions, field string, vector []float32, k int64,
+	boost float64, similarityMetric string, searchParams json.RawMessage,
+	eligibleSelector index.EligibleDocumentSelector) (
+	search.Searcher, error) {
+
+	if vr, ok := i.(index.VectorIndexReader); ok {
+		vectorReader, err := vr.VectorReader(ctx, vector, field, k, searchParams, eligibleSelector)
+		if err != nil {
+			return nil, err
+		}
+		knnScorer := scorer.NewKNNQueryScorer(vector, field, boost,
+			options, similarityMetric)
+		return &KNNSearcher{
+			indexReader:  i,
+			vectorReader: vectorReader,
+			field:        field,
+			vector:       vector,
+			k:            k,
+			scorer:       knnScorer,
+		}, nil
+	}
+	return nil, nil
+}
+
+func (s *KNNSearcher) VectorOptimize(ctx context.Context, octx index.VectorOptimizableContext) (
+	index.VectorOptimizableContext, error) {
+	o, ok := s.vectorReader.(index.VectorOptimizable)
+	if ok {
+		return o.VectorOptimize(ctx, octx)
+	}
+
+	return nil, nil
+}
+
+func (s *KNNSearcher) Advance(ctx *search.SearchContext, ID index.IndexInternalID) (
+	*search.DocumentMatch, error) {
+	knnMatch, err := s.vectorReader.Next(s.vd.Reset())
+	if err != nil {
+		return nil, err
+	}
+
+	if knnMatch == nil {
+		return nil, nil
+	}
+
+	docMatch := s.scorer.Score(ctx, knnMatch)
+
+	return docMatch, nil
+}
+
+func (s *KNNSearcher) Close() error {
+	return s.vectorReader.Close()
+}
+
+func (s *KNNSearcher) Count() uint64 {
+	return s.vectorReader.Count()
+}
+
+func (s *KNNSearcher) DocumentMatchPoolSize() int {
+	return 1
+}
+
+func (s *KNNSearcher) Min() int {
+	return 0
+}
+
+func (s *KNNSearcher) Next(ctx *search.SearchContext) (*search.DocumentMatch, error) {
+	knnMatch, err := s.vectorReader.Next(s.vd.Reset())
+	if err != nil {
+		return nil, err
+	}
+
+	if knnMatch == nil {
+		return nil, nil
+	}
+
+	docMatch := s.scorer.Score(ctx, knnMatch)
+
+	return docMatch, nil
+}
+
+func (s *KNNSearcher) SetQueryNorm(qnorm float64) {
+	s.scorer.SetQueryNorm(qnorm)
+}
+
+func (s *KNNSearcher) Size() int {
+	return reflectStaticSizeKNNSearcher + size.SizeOfPtr +
+		s.vectorReader.Size() +
+		s.vd.Size() +
+		s.scorer.Size()
+}
+
+func (s *KNNSearcher) Weight() float64 {
+	return s.scorer.Weight()
+}