githaven/vendor/github.com/blevesearch/bleve/search/searcher/search_geopointdistance.go
Lunny Xiao a380cfd8e0 Update bleve dependency to latest master revision (#6100)
* update bleve to master b17287a86f6cac923a5d886e10618df994eeb54b6724eac2e3b8dde89cfbe3a2

* remove unused pkg from dep file

* change bleve from master to recent revision
2019-02-17 19:50:26 -05:00

123 lines
3.8 KiB
Go

// 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 (
"github.com/blevesearch/bleve/geo"
"github.com/blevesearch/bleve/index"
"github.com/blevesearch/bleve/numeric"
"github.com/blevesearch/bleve/search"
)
func NewGeoPointDistanceSearcher(indexReader index.IndexReader, centerLon,
centerLat, dist float64, field string, boost float64,
options search.SearcherOptions) (search.Searcher, error) {
// 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
boxSearcher, err := boxSearcher(indexReader,
topLeftLon, topLeftLat, bottomRightLon, bottomRightLat,
field, boost, options)
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(boxSearcher,
buildDistFilter(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(indexReader index.IndexReader,
topLeftLon, topLeftLat, bottomRightLon, bottomRightLat float64,
field string, boost float64, options search.SearcherOptions) (
search.Searcher, error) {
if bottomRightLon < topLeftLon {
// cross date line, rewrite as two parts
leftSearcher, err := NewGeoBoundingBoxSearcher(indexReader,
-180, bottomRightLat, bottomRightLon, topLeftLat,
field, boost, options, false)
if err != nil {
return nil, err
}
rightSearcher, err := NewGeoBoundingBoxSearcher(indexReader,
topLeftLon, bottomRightLat, 180, topLeftLat, field, boost, options, false)
if err != nil {
_ = leftSearcher.Close()
return nil, err
}
boxSearcher, err := NewDisjunctionSearcher(indexReader,
[]search.Searcher{leftSearcher, rightSearcher}, 0, options)
if err != nil {
_ = leftSearcher.Close()
_ = rightSearcher.Close()
return nil, err
}
return boxSearcher, nil
}
// build geoboundinggox searcher for that bounding box
boxSearcher, err := NewGeoBoundingBoxSearcher(indexReader,
topLeftLon, bottomRightLat, bottomRightLon, topLeftLat, field, boost,
options, false)
if err != nil {
return nil, err
}
return boxSearcher, nil
}
func buildDistFilter(dvReader index.DocValueReader, field string,
centerLon, centerLat, maxDist float64) FilterFunc {
return func(d *search.DocumentMatch) bool {
var lon, lat 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 {
lon = geo.MortonUnhashLon(uint64(i64))
lat = geo.MortonUnhashLat(uint64(i64))
found = true
}
}
})
if err == nil && found {
dist := geo.Haversin(lon, lat, centerLon, centerLat)
if dist <= maxDist/1000 {
return true
}
}
return false
}
}