Adding upstream version 2.5.1.

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

search/scorer/scorer_constant.go

@@ -0,0 +1,132 @@
+//  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"
+	index "github.com/blevesearch/bleve_index_api"
+)
+
+var reflectStaticSizeConstantScorer int
+
+func init() {
+	var cs ConstantScorer
+	reflectStaticSizeConstantScorer = int(reflect.TypeOf(cs).Size())
+}
+
+type ConstantScorer struct {
+	constant               float64
+	boost                  float64
+	options                search.SearcherOptions
+	queryNorm              float64
+	queryWeight            float64
+	queryWeightExplanation *search.Explanation
+	includeScore           bool
+}
+
+func (s *ConstantScorer) Size() int {
+	sizeInBytes := reflectStaticSizeConstantScorer + size.SizeOfPtr
+
+	if s.queryWeightExplanation != nil {
+		sizeInBytes += s.queryWeightExplanation.Size()
+	}
+
+	return sizeInBytes
+}
+
+func NewConstantScorer(constant float64, boost float64, options search.SearcherOptions) *ConstantScorer {
+	rv := ConstantScorer{
+		options:      options,
+		queryWeight:  1.0,
+		constant:     constant,
+		boost:        boost,
+		includeScore: options.Score != "none",
+	}
+
+	return &rv
+}
+
+func (s *ConstantScorer) Weight() float64 {
+	sum := s.boost
+	return sum * sum
+}
+
+func (s *ConstantScorer) SetQueryNorm(qnorm float64) {
+	s.queryNorm = qnorm
+
+	// update the query weight
+	s.queryWeight = s.boost * s.queryNorm
+
+	if s.options.Explain {
+		childrenExplanations := make([]*search.Explanation, 2)
+		childrenExplanations[0] = &search.Explanation{
+			Value:   s.boost,
+			Message: "boost",
+		}
+		childrenExplanations[1] = &search.Explanation{
+			Value:   s.queryNorm,
+			Message: "queryNorm",
+		}
+		s.queryWeightExplanation = &search.Explanation{
+			Value:    s.queryWeight,
+			Message:  fmt.Sprintf("ConstantScore()^%f, product of:", s.boost),
+			Children: childrenExplanations,
+		}
+	}
+}
+
+func (s *ConstantScorer) Score(ctx *search.SearchContext, id index.IndexInternalID) *search.DocumentMatch {
+	var scoreExplanation *search.Explanation
+
+	rv := ctx.DocumentMatchPool.Get()
+	rv.IndexInternalID = id
+
+	if s.includeScore {
+		score := s.constant
+
+		if s.options.Explain {
+			scoreExplanation = &search.Explanation{
+				Value:   score,
+				Message: "ConstantScore()",
+			}
+		}
+
+		// if the query weight isn't 1, multiply
+		if s.queryWeight != 1.0 {
+			score = score * s.queryWeight
+			if s.options.Explain {
+				childExplanations := make([]*search.Explanation, 2)
+				childExplanations[0] = s.queryWeightExplanation
+				childExplanations[1] = scoreExplanation
+				scoreExplanation = &search.Explanation{
+					Value:    score,
+					Message:  fmt.Sprintf("weight(^%f), product of:", s.boost),
+					Children: childExplanations,
+				}
+			}
+		}
+
+		rv.Score = score
+		if s.options.Explain {
+			rv.Expl = scoreExplanation
+		}
+	}
+
+	return rv
+}