From de59d23ac41ae5e6eeb87fa776b166de20880100 Mon Sep 17 00:00:00 2001
From: tidwall <joshbaker77@gmail.com>
Date: Sun, 26 Sep 2021 06:09:43 -0700
Subject: [PATCH] Fixed Z not matching on where clause Feature points.

This issues fixes an issue where a search command with a where
clause using the "z" field would not match correctly for point
that where contained inside a GeoJSON Feature type.

Tile38 now extracts the Z coordinate from Point and Feature/Point
types.

fixes #622
---
 internal/server/crud.go    |  5 +----
 internal/server/json.go    |  5 +----
 internal/server/scanner.go | 26 ++++++++++++++++----------
 3 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/internal/server/crud.go b/internal/server/crud.go
index 08142c4f..4d90a700 100644
--- a/internal/server/crud.go
+++ b/internal/server/crud.go
@@ -183,10 +183,7 @@ func (server *Server) cmdGet(msg *Message) (resp.Value, error) {
 			buf.Write(appendJSONSimplePoint(nil, o))
 		} else {
 			point := o.Center()
-			var z float64
-			if gPoint, ok := o.(*geojson.Point); ok {
-				z = gPoint.Z()
-			}
+			z := extractZCoordinate(o)
 			if z != 0 {
 				vals = append(vals, resp.ArrayValue([]resp.Value{
 					resp.StringValue(strconv.FormatFloat(point.Y, 'f', -1, 64)),
diff --git a/internal/server/json.go b/internal/server/json.go
index ab7fb1be..4dad895d 100644
--- a/internal/server/json.go
+++ b/internal/server/json.go
@@ -133,10 +133,7 @@ func appendJSONSimpleBounds(dst []byte, o geojson.Object) []byte {
 
 func appendJSONSimplePoint(dst []byte, o geojson.Object) []byte {
 	point := o.Center()
-	var z float64
-	if gPoint, ok := o.(*geojson.Point); ok {
-		z = gPoint.Z()
-	}
+	z := extractZCoordinate(o)
 	dst = append(dst, `{"lat":`...)
 	dst = strconv.AppendFloat(dst, point.Y, 'f', -1, 64)
 	dst = append(dst, `,"lon":`...)
diff --git a/internal/server/scanner.go b/internal/server/scanner.go
index e11c14ad..d6b7955b 100644
--- a/internal/server/scanner.go
+++ b/internal/server/scanner.go
@@ -214,6 +214,19 @@ func (sw *scanWriter) writeFoot() {
 	}
 }
 
+func extractZCoordinate(o geojson.Object) float64 {
+	for {
+		switch g := o.(type) {
+		case *geojson.Point:
+			return g.Z()
+		case *geojson.Feature:
+			o = g.Base()
+		default:
+			return 0
+		}
+	}
+}
+
 func (sw *scanWriter) fieldMatch(fields []float64, o geojson.Object) (fvals []float64, match bool) {
 	var z float64
 	var gotz bool
@@ -222,9 +235,7 @@ func (sw *scanWriter) fieldMatch(fields []float64, o geojson.Object) (fvals []fl
 		for _, where := range sw.wheres {
 			if where.field == "z" {
 				if !gotz {
-					if point, ok := o.(*geojson.Point); ok {
-						z = point.Z()
-					}
+					z = extractZCoordinate(o)
 				}
 				if !where.match(z) {
 					return
@@ -270,9 +281,7 @@ func (sw *scanWriter) fieldMatch(fields []float64, o geojson.Object) (fvals []fl
 		for _, where := range sw.wheres {
 			if where.field == "z" {
 				if !gotz {
-					if point, ok := o.(*geojson.Point); ok {
-						z = point.Z()
-					}
+					z = extractZCoordinate(o)
 				}
 				if !where.match(z) {
 					return
@@ -455,10 +464,7 @@ func (sw *scanWriter) writeObject(opts ScanWriterParams) bool {
 				vals = append(vals, resp.StringValue(opts.o.String()))
 			case outputPoints:
 				point := opts.o.Center()
-				var z float64
-				if point, ok := opts.o.(*geojson.Point); ok {
-					z = point.Z()
-				}
+				z := extractZCoordinate(opts.o)
 				if z != 0 {
 					vals = append(vals, resp.ArrayValue([]resp.Value{
 						resp.FloatValue(point.Y),