forked from gitea/gitea
123 lines
3.8 KiB
Go
123 lines
3.8 KiB
Go
// Copyright (c) 2017 Couchbase, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package searcher
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import (
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"github.com/blevesearch/bleve/geo"
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"github.com/blevesearch/bleve/index"
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"github.com/blevesearch/bleve/numeric"
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"github.com/blevesearch/bleve/search"
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)
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func NewGeoPointDistanceSearcher(indexReader index.IndexReader, centerLon,
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centerLat, dist float64, field string, boost float64,
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options search.SearcherOptions) (search.Searcher, error) {
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// compute bounding box containing the circle
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topLeftLon, topLeftLat, bottomRightLon, bottomRightLat, err :=
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geo.RectFromPointDistance(centerLon, centerLat, dist)
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if err != nil {
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return nil, err
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}
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// build a searcher for the box
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boxSearcher, err := boxSearcher(indexReader,
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topLeftLon, topLeftLat, bottomRightLon, bottomRightLat,
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field, boost, options)
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if err != nil {
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return nil, err
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}
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dvReader, err := indexReader.DocValueReader([]string{field})
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if err != nil {
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return nil, err
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}
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// wrap it in a filtering searcher which checks the actual distance
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return NewFilteringSearcher(boxSearcher,
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buildDistFilter(dvReader, field, centerLon, centerLat, dist)), nil
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}
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// boxSearcher builds a searcher for the described bounding box
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// if the desired box crosses the dateline, it is automatically split into
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// two boxes joined through a disjunction searcher
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func boxSearcher(indexReader index.IndexReader,
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topLeftLon, topLeftLat, bottomRightLon, bottomRightLat float64,
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field string, boost float64, options search.SearcherOptions) (
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search.Searcher, error) {
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if bottomRightLon < topLeftLon {
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// cross date line, rewrite as two parts
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leftSearcher, err := NewGeoBoundingBoxSearcher(indexReader,
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-180, bottomRightLat, bottomRightLon, topLeftLat,
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field, boost, options, false)
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if err != nil {
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return nil, err
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}
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rightSearcher, err := NewGeoBoundingBoxSearcher(indexReader,
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topLeftLon, bottomRightLat, 180, topLeftLat, field, boost, options, false)
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if err != nil {
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_ = leftSearcher.Close()
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return nil, err
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}
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boxSearcher, err := NewDisjunctionSearcher(indexReader,
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[]search.Searcher{leftSearcher, rightSearcher}, 0, options)
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if err != nil {
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_ = leftSearcher.Close()
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_ = rightSearcher.Close()
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return nil, err
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}
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return boxSearcher, nil
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}
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// build geoboundinggox searcher for that bounding box
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boxSearcher, err := NewGeoBoundingBoxSearcher(indexReader,
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topLeftLon, bottomRightLat, bottomRightLon, topLeftLat, field, boost,
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options, false)
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if err != nil {
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return nil, err
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}
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return boxSearcher, nil
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}
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func buildDistFilter(dvReader index.DocValueReader, field string,
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centerLon, centerLat, maxDist float64) FilterFunc {
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return func(d *search.DocumentMatch) bool {
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var lon, lat float64
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var found bool
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err := dvReader.VisitDocValues(d.IndexInternalID, func(field string, term []byte) {
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// only consider the values which are shifted 0
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prefixCoded := numeric.PrefixCoded(term)
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shift, err := prefixCoded.Shift()
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if err == nil && shift == 0 {
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i64, err := prefixCoded.Int64()
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if err == nil {
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lon = geo.MortonUnhashLon(uint64(i64))
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lat = geo.MortonUnhashLat(uint64(i64))
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found = true
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}
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}
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})
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if err == nil && found {
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dist := geo.Haversin(lon, lat, centerLon, centerLat)
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if dist <= maxDist/1000 {
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return true
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}
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}
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return false
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}
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}
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