From 4de5d987d7aa3d4f4fec9d0a6fa1a71923970b19 Mon Sep 17 00:00:00 2001
From: Oliver Tonnhofer <olt@bogosoft.com>
Date: Wed, 1 Feb 2017 11:59:41 +0100
Subject: [PATCH] do not expire clipped ways/relations

---
 writer/relations.go |  3 +++
 writer/ways.go      | 32 +++++++++++++++++---------------
 2 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/writer/relations.go b/writer/relations.go
index 3af283a..53a8043 100644
--- a/writer/relations.go
+++ b/writer/relations.go
@@ -172,6 +172,9 @@ func handleMultiPolygon(rw *RelationWriter, r *element.Relation, geos *geosp.Geo
 		if duration := time.Now().Sub(start); duration > time.Minute {
 			log.Warnf("clipping relation %d to -limitto took %s", r.Id, duration)
 		}
+		if len(parts) == 0 {
+			return false
+		}
 		for _, g := range parts {
 			rel := element.Relation(*r)
 			rel.Id = rw.relId(r.Id)
diff --git a/writer/ways.go b/writer/ways.go
index 1f770fa..a11de60 100644
--- a/writer/ways.go
+++ b/writer/ways.go
@@ -89,31 +89,28 @@ func (ww *WayWriter) loop() {
 		inserted := false
 		insertedPolygon := false
 		if matches := ww.lineMatcher.MatchWay(w); len(matches) > 0 {
-			err := ww.buildAndInsert(geos, w, matches, false)
+			err, inserted = ww.buildAndInsert(geos, w, matches, false)
 			if err != nil {
 				if errl, ok := err.(ErrorLevel); !ok || errl.Level() > 0 {
 					log.Warn(err)
 				}
 				continue
 			}
-			inserted = true
 		}
 		if !insertedAsRelation && (w.IsClosed() || w.TryClose(ww.maxGap)) {
 			// only add polygons that were not inserted as a MultiPolygon relation
 			if matches := ww.polygonMatcher.MatchWay(w); len(matches) > 0 {
-				err := ww.buildAndInsert(geos, w, matches, true)
+				err, insertedPolygon = ww.buildAndInsert(geos, w, matches, true)
 				if err != nil {
 					if errl, ok := err.(ErrorLevel); !ok || errl.Level() > 0 {
 						log.Warn(err)
 					}
 					continue
 				}
-				inserted = true
-				insertedPolygon = true
 			}
 		}
 
-		if inserted && ww.expireor != nil {
+		if (inserted || insertedPolygon) && ww.expireor != nil {
 			expire.ExpireProjectedNodes(ww.expireor, w.Nodes, ww.srid, insertedPolygon)
 		}
 		if ww.diffCache != nil {
@@ -123,7 +120,7 @@ func (ww *WayWriter) loop() {
 	ww.wg.Done()
 }
 
-func (ww *WayWriter) buildAndInsert(g *geos.Geos, w *element.Way, matches []mapping.Match, isPolygon bool) error {
+func (ww *WayWriter) buildAndInsert(g *geos.Geos, w *element.Way, matches []mapping.Match, isPolygon bool) (error, bool) {
 	var err error
 	var geosgeom *geos.Geom
 	// make copy to avoid interference with polygon/linestring matches
@@ -138,42 +135,47 @@ func (ww *WayWriter) buildAndInsert(g *geos.Geos, w *element.Way, matches []mapp
 		geosgeom, err = geomp.LineString(g, way.Nodes)
 	}
 	if err != nil {
-		return err
+		return err, false
 	}
 
 	geom, err := geomp.AsGeomElement(g, geosgeom)
 	if err != nil {
-		return err
+		return err, false
 	}
 
+	inserted := true
 	if ww.limiter != nil {
 		parts, err := ww.limiter.Clip(geom.Geom)
 		if err != nil {
-			return err
+			return err, false
+		}
+		if len(parts) == 0 {
+			// outside of limitto
+			inserted = false
 		}
 		for _, p := range parts {
 			way := element.Way(*w)
 			geom = geomp.Geometry{Geom: p, Wkb: g.AsEwkbHex(p)}
 			if isPolygon {
 				if err := ww.inserter.InsertPolygon(way.OSMElem, geom, matches); err != nil {
-					return err
+					return err, false
 				}
 			} else {
 				if err := ww.inserter.InsertLineString(way.OSMElem, geom, matches); err != nil {
-					return err
+					return err, false
 				}
 			}
 		}
 	} else {
 		if isPolygon {
 			if err := ww.inserter.InsertPolygon(way.OSMElem, geom, matches); err != nil {
-				return err
+				return err, false
 			}
 		} else {
 			if err := ww.inserter.InsertLineString(way.OSMElem, geom, matches); err != nil {
-				return err
+				return err, false
 			}
 		}
 	}
-	return nil
+	return nil, inserted
 }