Adding upstream version 2.5.1.

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

search/scorer/scorer_disjunction.go

@@ -0,0 +1,123 @@
+//  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 scorer
+
+import (
+	"fmt"
+	"reflect"
+
+	"github.com/blevesearch/bleve/v2/search"
+	"github.com/blevesearch/bleve/v2/size"
+)
+
+var reflectStaticSizeDisjunctionQueryScorer int
+
+func init() {
+	var dqs DisjunctionQueryScorer
+	reflectStaticSizeDisjunctionQueryScorer = int(reflect.TypeOf(dqs).Size())
+}
+
+type DisjunctionQueryScorer struct {
+	options search.SearcherOptions
+}
+
+func (s *DisjunctionQueryScorer) Size() int {
+	return reflectStaticSizeDisjunctionQueryScorer + size.SizeOfPtr
+}
+
+func NewDisjunctionQueryScorer(options search.SearcherOptions) *DisjunctionQueryScorer {
+	return &DisjunctionQueryScorer{
+		options: options,
+	}
+}
+
+func (s *DisjunctionQueryScorer) Score(ctx *search.SearchContext, constituents []*search.DocumentMatch, countMatch, countTotal int) *search.DocumentMatch {
+	var sum float64
+	var childrenExplanations []*search.Explanation
+	if s.options.Explain {
+		childrenExplanations = make([]*search.Explanation, len(constituents))
+	}
+
+	for i, docMatch := range constituents {
+		sum += docMatch.Score
+		if s.options.Explain {
+			childrenExplanations[i] = docMatch.Expl
+		}
+	}
+
+	var rawExpl *search.Explanation
+	if s.options.Explain {
+		rawExpl = &search.Explanation{Value: sum, Message: "sum of:", Children: childrenExplanations}
+	}
+
+	coord := float64(countMatch) / float64(countTotal)
+	newScore := sum * coord
+	var newExpl *search.Explanation
+	if s.options.Explain {
+		ce := make([]*search.Explanation, 2)
+		ce[0] = rawExpl
+		ce[1] = &search.Explanation{Value: coord, Message: fmt.Sprintf("coord(%d/%d)", countMatch, countTotal)}
+		newExpl = &search.Explanation{Value: newScore, Message: "product of:", Children: ce, PartialMatch: countMatch != countTotal}
+	}
+
+	// reuse constituents[0] as the return value
+	rv := constituents[0]
+	rv.Score = newScore
+	rv.Expl = newExpl
+	rv.FieldTermLocations = search.MergeFieldTermLocations(
+		rv.FieldTermLocations, constituents[1:])
+
+	return rv
+}
+
+// This method is used only when disjunction searcher is used over multiple
+// KNN searchers, where only the score breakdown and the optional explanation breakdown
+// is required. The final score and explanation is set when we finalize the KNN hits.
+func (s *DisjunctionQueryScorer) ScoreAndExplBreakdown(ctx *search.SearchContext, constituents []*search.DocumentMatch,
+	matchingIdxs []int, originalPositions []int, countTotal int) *search.DocumentMatch {
+
+	scoreBreakdown := make(map[int]float64)
+	var childrenExplanations []*search.Explanation
+	if s.options.Explain {
+		// since we want to notify which expl belongs to which matched searcher within the disjunction searcher
+		childrenExplanations = make([]*search.Explanation, countTotal)
+	}
+
+	for i, docMatch := range constituents {
+		var index int
+		if originalPositions != nil {
+			// scorer used in disjunction slice searcher
+			index = originalPositions[matchingIdxs[i]]
+		} else {
+			// scorer used in disjunction heap searcher
+			index = matchingIdxs[i]
+		}
+		scoreBreakdown[index] = docMatch.Score
+		if s.options.Explain {
+			childrenExplanations[index] = docMatch.Expl
+		}
+	}
+	var explBreakdown *search.Explanation
+	if s.options.Explain {
+		explBreakdown = &search.Explanation{Children: childrenExplanations}
+	}
+
+	rv := constituents[0]
+	rv.ScoreBreakdown = scoreBreakdown
+	rv.Expl = explBreakdown
+	rv.FieldTermLocations = search.MergeFieldTermLocations(
+		rv.FieldTermLocations, constituents[1:])
+	return rv
+}