Make n_points function for geometries available in Lua

Author: joto

src/flex-lua-geom.cpp

@@ -114,6 +114,19 @@ int geom_centroid(lua_State *lua_state)
     return 1;
 }
 
+int geom_n_points(lua_State *lua_state)
+{
+    auto const *const input_geometry = unpack_geometry(lua_state);
+
+    try {
+        lua_pushinteger(lua_state, input_geometry->n_points());
+    } catch (...) {
+        return luaL_error(lua_state, "Unknown error in 'n_points()'.\n");
+    }
+
+    return 1;
+}
+
 int geom_geometry_n(lua_State *lua_state)
 {
     auto const *const input_geometry = unpack_geometry(lua_state);
@@ -313,6 +326,7 @@ void init_geometry_class(lua_State *lua_state)
          {"geometry_type", geom_geometry_type},
          {"is_null", geom_is_null},
          {"line_merge", geom_line_merge},
+         {"n_points", geom_n_points},
          {"reverse", geom_reverse},
          {"num_geometries", geom_num_geometries},
          {"pole_of_inaccessibility", geom_pole_of_inaccessibility},

tests/bdd/flex/geometry-linestring.feature

@@ -16,14 +16,16 @@ Feature: Creating linestring features from way
                 { column = 'sgeom', type = 'linestring', projection = 4326 },
                 { column = 'mgeom', type = 'multilinestring', projection = 4326 },
                 { column = 'xgeom', type = 'multilinestring', projection = 4326 },
+                { column = 'npoints', type = 'int' },
             })
 
             function osm2pgsql.process_way(object)
                 if object.tags.highway == 'motorway' then
                     lines:insert({
                         sgeom = object:as_linestring(),
                         mgeom = object:as_multilinestring(),
-                        xgeom = object:as_linestring()
+                        xgeom = object:as_linestring(),
+                        npoints = object:as_linestring():n_points(),
                     })
                 end
             end
@@ -32,9 +34,9 @@ Feature: Creating linestring features from way
         When running osm2pgsql flex
 
         Then table osm2pgsql_test_lines contains exactly
-            | way_id | sgeom!geo | mgeom!geo   | xgeom!geo   |
-            | 20     | 1, 2, 3   | [ 1, 2, 3 ] | [ 1, 2, 3 ] |
-            | 21     | 4, 5      | [ 4, 5 ]    | [ 4, 5 ]    |
+            | way_id | sgeom!geo | mgeom!geo   | xgeom!geo   | npoints |
+            | 20     | 1, 2, 3   | [ 1, 2, 3 ] | [ 1, 2, 3 ] | 3       |
+            | 21     | 4, 5      | [ 4, 5 ]    | [ 4, 5 ]    | 2       |
 
     Scenario:
         Given the grid