fix import of relations without way members when using -limitto

cache/osm.go

@@ -3,9 +3,11 @@ package cache
 import (
 	bin "encoding/binary"
 	"errors"
-	"github.com/jmhodges/levigo"
 	"os"
 	"path/filepath"
+
+	"github.com/jmhodges/levigo"
+	"github.com/omniscale/imposm3/element"
 )
 
 var (
@@ -129,6 +131,33 @@ func (c *OSMCache) Remove() error {
 	return nil
 }
 
+// FirstMemberIsCached checks whether the first way or node member is cached.
+// Also returns true if there are no members of type WAY or NODE.
+func (c *OSMCache) FirstMemberIsCached(members []element.Member) (bool, error) {
+	for _, m := range members {
+		if m.Type == element.WAY {
+			_, err := c.Ways.GetWay(m.Id)
+			if err == NotFound {
+				return false, nil
+			}
+			if err != nil {
+				return false, err
+			}
+			return true, nil
+		} else if m.Type == element.NODE {
+			_, err := c.Coords.GetCoord(m.Id)
+			if err == NotFound {
+				return false, nil
+			}
+			if err != nil {
+				return false, err
+			}
+			return true, nil
+		}
+	}
+	return true, nil
+}
+
 type cache struct {
 	db      *levigo.DB
 	options *cacheOptions

cache/ways.go

@@ -113,22 +113,6 @@ func (self *WaysCache) FillMembers(members []element.Member) error {
 	return nil
 }
 
-func (self *WaysCache) FirstMemberIsCached(members []element.Member) (bool, error) {
-	for _, m := range members {
-		if m.Type == element.WAY {
-			_, err := self.GetWay(m.Id)
-			if err == NotFound {
-				return false, nil
-			}
-			if err != nil {
-				return false, err
-			}
-			return true, nil
-		}
-	}
-	return false, nil
-}
-
 type InsertedWaysCache struct {
 	cache
 }

diff/process.go

@@ -242,7 +242,7 @@ func Update(oscFile string, geometryLimiter *limit.Limiter, expireor expire.Expi
 				if elem.Rel != nil {
 					// check if first member is cached to avoid caching
 					// unneeded relations (typical outside of our coverage)
-					cached, err := osmCache.Ways.FirstMemberIsCached(elem.Rel.Members)
+					cached, err := osmCache.FirstMemberIsCached(elem.Rel.Members)
 					if err != nil {
 						return diffError(err, "query first member %v", elem.Rel)
 					}

reader/reader.go

@@ -152,7 +152,7 @@ func ReadPbf(cache *osmcache.OSMCache, progress *stats.Statistics,
 						numWithTags += 1
 					}
 					if withLimiter {
-						cached, err := cache.Ways.FirstMemberIsCached(rels[i].Members)
+						cached, err := cache.FirstMemberIsCached(rels[i].Members)
 						if err != nil {
 							log.Errorf("error while checking for cached members of relation %d: %v", rels[i].Id, err)
 							cached = true // don't skip in case of error