fix(splitting): preserve geometry

Fixes #511

src/main/java/com/conveyal/r5/streets/EdgeStore.java

@@ -30,6 +30,7 @@
 
 import java.io.Serializable;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.EnumSet;
 import java.util.List;
 import java.util.Set;
@@ -728,6 +729,32 @@ public boolean canTurnFrom(StreetRouter.State s0, StreetRouter.State s1,
             return true;
         }
 
+        /**
+         * Cut the packed list of intermediate coordinates in two after specified segment
+         * @return List with first element int[] of coordinates before end of specified segment, and second element
+         * int[] of coordinates after end of specified segment.
+         */
+        public ArrayList<int[]> splitGeometryAfter(int segment) {
+            // Original packed coordinates of edge
+            int[] original = geometries.get(pairIndex);
+            ArrayList<int[]> geoms = new ArrayList<>();
+            geoms.add(Arrays.copyOfRange(original, 0, segment * 2)); // Multiply by 2 because packed array
+            geoms.add(Arrays.copyOfRange(original, segment * 2, original.length + 1));
+            return geoms;
+        }
+
+        /**
+         * Set intermediate coordinates directly with packed array
+         * @param coordinates Packed lists of lat, lon, lat, lon... as fixed-point integers
+         */
+        public void setGeometry (int[] coordinates) {
+            geometries.set(pairIndex, coordinates);
+            calculateAngles();
+        }
+
+        /**
+         * Set intermediate coordinates from OSM nodes
+         */
         public void setGeometry (List<Node> nodes) {
             // The same empty int array represents all straight-line edges.
             if (nodes.size() <= 2) {

src/main/java/com/conveyal/r5/streets/Split.java

@@ -156,7 +156,6 @@ public static Split find (double lat, double lon, double searchRadiusMeters, Str
 
         // We found an edge. Iterate over its segments again, accumulating distances along its geometry.
         // The distance calculations involve square roots so are deferred to happen here, only on the selected edge.
-        // TODO accumulate before/after geoms. Split point can be passed over since it's not an intermediate.
         // The length is are stored in one-element array to dodge Java's "effectively final" BS.
         edge.seek(best.edge);
         best.vertex0 = edge.getFromVertex();

src/main/java/com/conveyal/r5/streets/StreetLayer.java

@@ -1170,16 +1170,16 @@ public int getOrCreateVertexNear(double lat, double lon, StreetMode streetMode)
         // The split is somewhere along a street away from an existing intersection vertex. Make a new splitter vertex.
         int newVertexIndex = vertexStore.addVertexFixed((int) split.fixedLat, (int) split.fixedLon);
         int oldToVertex = edge.getToVertex(); // Hold a copy of the to vertex index, because it may be modified below.
+        ArrayList<int[]> geoms = new ArrayList<>();
         if (edge.isMutable()) {
             // The edge we are going to split is mutable.
             // We're either building a baseline graph, or modifying an edge created within the same scenario.
             // Modify the existing bidirectional edge pair to serve as the first segment leading up to the split point.
             // Its spatial index entry is still valid, since the edge's envelope will only shrink.
             edge.setLengthMm(split.distance0_mm);
             edge.setToVertex(newVertexIndex);
-            // Turn the edge into a straight line.
-            // FIXME split edges and new edges should have geometries!
-            edge.setGeometry(Collections.EMPTY_LIST);
+            geoms = edge.splitGeometryAfter(split.seg);
+            edge.setGeometry(geoms.get(0));
         } else {
             // The edge we are going to split is immutable, and should be left as-is.
             // We must be applying a scenario, and this edge is part of the baseline graph shared between threads.
@@ -1207,6 +1207,9 @@ public int getOrCreateVertexNear(double lat, double lon, StreetMode streetMode)
         EdgeStore.Edge newEdge1 = edgeStore.addStreetPair(newVertexIndex, oldToVertex, split.distance1_mm, edge.getOSMID());
         // Copy the flags and speeds for both directions, making newEdge1 like the existing edge.
         newEdge1.copyPairFlagsAndSpeeds(edge);
+
+        if (geoms.size() > 1) newEdge1.setGeometry(geoms.get(1));
+
         // Insert the new edge into the spatial index
         if (!edgeStore.isExtendOnlyCopy()) {
             spatialIndex.insert(newEdge1.getEnvelope(), newEdge1.edgeIndex);

src/test/java/com/conveyal/r5/streets/StreetLayerTest.java

@@ -122,6 +122,9 @@ public void testSplits() throws Exception {
         //assertEquals(backwardEdgeName, newBackwardEdge.getName());
 
         //streetLayer.edgeStore.dump();
+
+        // TODO: check lengths and geometries of curvilinear edges after repeated splitting
+
     }
 
     /** Test that simple turn restrictions (no via ways) are read properly, using http://www.openstreetmap.org/relation/5696764 */