Adding upstream version 2.5.1.

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

search/searcher/search_geopointdistance.go

@@ -0,0 +1,151 @@
+//  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/geo"
+	"github.com/blevesearch/bleve/v2/numeric"
+	"github.com/blevesearch/bleve/v2/search"
+	index "github.com/blevesearch/bleve_index_api"
+)
+
+func NewGeoPointDistanceSearcher(ctx context.Context, indexReader index.IndexReader, centerLon,
+	centerLat, dist float64, field string, boost float64,
+	options search.SearcherOptions) (search.Searcher, error) {
+	var rectSearcher search.Searcher
+	if tp, ok := indexReader.(index.SpatialIndexPlugin); ok {
+		sp, err := tp.GetSpatialAnalyzerPlugin("s2")
+		if err == nil {
+			terms := sp.GetQueryTokens(geo.NewPointDistance(centerLat,
+				centerLon, dist))
+			rectSearcher, err = NewMultiTermSearcher(ctx, indexReader, terms,
+				field, boost, options, false)
+			if err != nil {
+				return nil, err
+			}
+		}
+	}
+
+	// indexes without the spatial plugin override would get
+	// initialized here.
+	if rectSearcher == nil {
+		// compute bounding box containing the circle
+		topLeftLon, topLeftLat, bottomRightLon, bottomRightLat, err :=
+			geo.RectFromPointDistance(centerLon, centerLat, dist)
+		if err != nil {
+			return nil, err
+		}
+
+		// build a searcher for the box
+		rectSearcher, err = boxSearcher(ctx, indexReader,
+			topLeftLon, topLeftLat, bottomRightLon, bottomRightLat,
+			field, boost, options, false)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	dvReader, err := indexReader.DocValueReader([]string{field})
+	if err != nil {
+		return nil, err
+	}
+
+	// wrap it in a filtering searcher which checks the actual distance
+	return NewFilteringSearcher(ctx, rectSearcher,
+		buildDistFilter(ctx, dvReader, field, centerLon, centerLat, dist)), nil
+}
+
+// boxSearcher builds a searcher for the described bounding box
+// if the desired box crosses the dateline, it is automatically split into
+// two boxes joined through a disjunction searcher
+func boxSearcher(ctx context.Context, indexReader index.IndexReader,
+	topLeftLon, topLeftLat, bottomRightLon, bottomRightLat float64,
+	field string, boost float64, options search.SearcherOptions, checkBoundaries bool) (
+	search.Searcher, error) {
+	if bottomRightLon < topLeftLon {
+		// cross date line, rewrite as two parts
+
+		leftSearcher, err := NewGeoBoundingBoxSearcher(ctx, indexReader,
+			-180, bottomRightLat, bottomRightLon, topLeftLat,
+			field, boost, options, checkBoundaries)
+		if err != nil {
+			return nil, err
+		}
+		rightSearcher, err := NewGeoBoundingBoxSearcher(ctx, indexReader,
+			topLeftLon, bottomRightLat, 180, topLeftLat, field, boost, options,
+			checkBoundaries)
+		if err != nil {
+			_ = leftSearcher.Close()
+			return nil, err
+		}
+
+		boxSearcher, err := NewDisjunctionSearcher(ctx, indexReader,
+			[]search.Searcher{leftSearcher, rightSearcher}, 0, options)
+		if err != nil {
+			_ = leftSearcher.Close()
+			_ = rightSearcher.Close()
+			return nil, err
+		}
+		return boxSearcher, nil
+	}
+
+	// build geoboundingbox searcher for that bounding box
+	boxSearcher, err := NewGeoBoundingBoxSearcher(ctx, indexReader,
+		topLeftLon, bottomRightLat, bottomRightLon, topLeftLat, field, boost,
+		options, checkBoundaries)
+	if err != nil {
+		return nil, err
+	}
+	return boxSearcher, nil
+}
+
+func buildDistFilter(ctx context.Context, dvReader index.DocValueReader, field string,
+	centerLon, centerLat, maxDist float64) FilterFunc {
+	return func(d *search.DocumentMatch) bool {
+		// check geo matches against all numeric type terms indexed
+		var lons, lats []float64
+		var found bool
+
+		err := dvReader.VisitDocValues(d.IndexInternalID, func(field string, term []byte) {
+			// only consider the values which are shifted 0
+			prefixCoded := numeric.PrefixCoded(term)
+			shift, err := prefixCoded.Shift()
+			if err == nil && shift == 0 {
+				i64, err := prefixCoded.Int64()
+				if err == nil {
+					lons = append(lons, geo.MortonUnhashLon(uint64(i64)))
+					lats = append(lats, geo.MortonUnhashLat(uint64(i64)))
+					found = true
+				}
+			}
+		})
+		if err == nil && found {
+			bytes := dvReader.BytesRead()
+			if bytes > 0 {
+				reportIOStats(ctx, bytes)
+				search.RecordSearchCost(ctx, search.AddM, bytes)
+			}
+			for i := range lons {
+				dist := geo.Haversin(lons[i], lats[i], centerLon, centerLat)
+				if dist <= maxDist/1000 {
+					return true
+				}
+			}
+		}
+		return false
+	}
+}