From 248ccfbe8a20483056f5c226940aa7bcdb04c57a Mon Sep 17 00:00:00 2001
From: Josh Baker <joshbaker77@gmail.com>
Date: Fri, 9 Mar 2018 19:50:34 -0700
Subject: [PATCH] Filter id match before kNN results

fixes #280
---
 controller/scanner.go | 55 ++++++++++++++++++++++++++-----------------
 controller/search.go  | 31 ++++++++++++++++--------
 2 files changed, 54 insertions(+), 32 deletions(-)

diff --git a/controller/scanner.go b/controller/scanner.go
index dedf004b..d48c67c9 100644
--- a/controller/scanner.go
+++ b/controller/scanner.go
@@ -59,11 +59,12 @@ type scanWriter struct {
 }
 
 type ScanWriterParams struct {
-	id       string
-	o        geojson.Object
-	fields   []float64
-	distance float64
-	noLock   bool
+	id              string
+	o               geojson.Object
+	fields          []float64
+	distance        float64
+	noLock          bool
+	ignoreGlobMatch bool
 }
 
 func (c *Controller) newScanWriter(
@@ -294,6 +295,28 @@ func (sw *scanWriter) fieldMatch(fields []float64, o geojson.Object) (fvals []fl
 	return
 }
 
+func (sw *scanWriter) globMatch(id string, o geojson.Object) (ok, keepGoing bool) {
+	if !sw.globEverything {
+		if sw.globSingle {
+			if sw.globPattern != id {
+				return false, true
+			}
+			return true, false
+		}
+		var val string
+		if sw.matchValues {
+			val = o.String()
+		} else {
+			val = id
+		}
+		ok, _ := glob.Match(sw.globPattern, val)
+		if !ok {
+			return false, true
+		}
+	}
+	return true, true
+}
+
 //id string, o geojson.Object, fields []float64, noLock bool
 func (sw *scanWriter) writeObject(opts ScanWriterParams) bool {
 	if !opts.noLock {
@@ -301,23 +324,11 @@ func (sw *scanWriter) writeObject(opts ScanWriterParams) bool {
 		defer sw.mu.Unlock()
 	}
 	keepGoing := true
-	if !sw.globEverything {
-		if sw.globSingle {
-			if sw.globPattern != opts.id {
-				return true
-			}
-			keepGoing = false // return current object and stop iterating
-		} else {
-			var val string
-			if sw.matchValues {
-				val = opts.o.String()
-			} else {
-				val = opts.id
-			}
-			ok, _ := glob.Match(sw.globPattern, val)
-			if !ok {
-				return true
-			}
+	if !opts.ignoreGlobMatch {
+		var match bool
+		match, keepGoing = sw.globMatch(opts.id, opts.o)
+		if !match {
+			return true
 		}
 	}
 	nfields, ok := sw.fieldMatch(opts.fields, opts.o)
diff --git a/controller/search.go b/controller/search.go
index e5a8a991..7c7cfe3d 100644
--- a/controller/search.go
+++ b/controller/search.go
@@ -328,6 +328,7 @@ func (c *Controller) cmdNearby(msg *server.Message) (res resp.Value, err error)
 	}
 	sw.writeHead()
 	if sw.col != nil {
+		var matched uint32
 		iter := func(id string, o geojson.Object, fields []float64, dist *float64) bool {
 			if c.hasExpired(s.key, id) {
 				return true
@@ -342,15 +343,16 @@ func (c *Controller) cmdNearby(msg *server.Message) (res resp.Value, err error)
 				}
 			}
 			return sw.writeObject(ScanWriterParams{
-				id:       id,
-				o:        o,
-				fields:   fields,
-				distance: distance,
-				noLock:   true,
+				id:              id,
+				o:               o,
+				fields:          fields,
+				distance:        distance,
+				noLock:          true,
+				ignoreGlobMatch: s.knn,
 			})
 		}
 		if s.knn {
-			nearestNeighbors(sw, s.lat, s.lon, iter)
+			nearestNeighbors(sw, s.lat, s.lon, &matched, iter)
 		} else {
 			sw.col.Nearby(s.sparse, s.lat, s.lon, s.meters, minZ, maxZ,
 				func(id string, o geojson.Object, fields []float64) bool {
@@ -374,13 +376,22 @@ type iterItem struct {
 	dist   float64
 }
 
-func nearestNeighbors(sw *scanWriter, lat, lon float64, iter func(id string, o geojson.Object, fields []float64, dist *float64) bool) {
+func nearestNeighbors(sw *scanWriter, lat, lon float64, matched *uint32,
+	iter func(id string, o geojson.Object, fields []float64, dist *float64) bool) {
 	limit := int(sw.cursor + sw.limit)
 	var items []iterItem
 	sw.col.NearestNeighbors(lat, lon, func(id string, o geojson.Object, fields []float64) bool {
-		if _, ok := sw.fieldMatch(fields, o); ok {
-			dist := o.CalculatedPoint().DistanceTo(geojson.Position{X: lon, Y: lat, Z: 0})
-			items = append(items, iterItem{id: id, o: o, fields: fields, dist: dist})
+		if _, ok := sw.fieldMatch(fields, o); !ok {
+			return true
+		}
+		match, keepGoing := sw.globMatch(id, o)
+		if !match {
+			return true
+		}
+		dist := o.CalculatedPoint().DistanceTo(geojson.Position{X: lon, Y: lat, Z: 0})
+		items = append(items, iterItem{id: id, o: o, fields: fields, dist: dist})
+		if !keepGoing {
+			return false
 		}
 		return len(items) < limit
 	})