Allow calling as_multilinestring/as_multipolygon from ways

Author: joto

src/output-flex.cpp

@@ -885,9 +885,18 @@ int output_flex_t::app_as_polygon()
 
 int output_flex_t::app_as_multilinestring()
 {
-    check_context_and_state("as_multilinestring", "process_relation() function",
-                            m_calling_context !=
-                                calling_context::process_relation);
+    check_context_and_state(
+        "as_multilinestring", "process_way/relation() functions",
+        m_calling_context != calling_context::process_way &&
+            m_calling_context != calling_context::process_relation);
+
+    if (m_calling_context == calling_context::process_way) {
+        m_way_cache.add_nodes(middle());
+
+        auto *geom = create_lua_geometry_object(lua_state());
+        geom::create_linestring(geom, m_way_cache.get());
+        return 1;
+    }
 
     m_relation_cache.add_members(middle());
 
@@ -900,9 +909,19 @@ int output_flex_t::app_as_multilinestring()
 
 int output_flex_t::app_as_multipolygon()
 {
-    check_context_and_state("as_multipolygon", "process_relation() function",
-                            m_calling_context !=
-                                calling_context::process_relation);
+    check_context_and_state(
+        "as_multipolygon", "process_way/relation() functions",
+        m_calling_context != calling_context::process_way &&
+            m_calling_context != calling_context::process_relation);
+
+    if (m_calling_context == calling_context::process_way) {
+        m_way_cache.add_nodes(middle());
+
+        auto *geom = create_lua_geometry_object(lua_state());
+        geom::create_polygon(geom, m_way_cache.get());
+
+        return 1;
+    }
 
     m_relation_cache.add_members(middle());
 

tests/bdd/flex/geometry-multilinestring.feature

@@ -0,0 +1,49 @@
+Feature: Creating (multi)linestring features from way and relations
+
+    Scenario:
+        Given the grid
+            | 1 | 2 |   |
+            | 4 |   | 3 |
+            |   | 5 | 6 |
+        And the OSM data
+            """
+            w20 Thighway=motorway Nn1,n2,n3
+            w21 Thighway=motorway Nn4,n5,n6
+            r30 Ttype=route,route=road Mw20@
+            r31 Ttype=route,route=road Mw20@,w21@
+            """
+        And the lua style
+            """
+            local lines = osm2pgsql.define_table({
+                name = 'osm2pgsql_test_lines',
+                ids = { type = 'any', id_column = 'osm_id', type_column = 'osm_type' },
+                columns = {
+                    { column = 'geom', type = 'geometry', projection = 4326 },
+                }
+            })
+
+            function osm2pgsql.process_way(object)
+                if object.tags.highway == 'motorway' then
+                    lines:insert({
+                        geom = object:as_multilinestring()
+                    })
+                end
+            end
+
+            function osm2pgsql.process_relation(object)
+                if object.tags.type == 'route' then
+                    lines:insert({
+                        geom = object:as_multilinestring()
+                    })
+                end
+            end
+            """
+        When running osm2pgsql flex
+
+        Then table osm2pgsql_test_lines contains exactly
+            | osm_type | osm_id | ST_GeometryType(geom) | ST_AsText(ST_GeometryN(geom, 1)) | ST_AsText(ST_GeometryN(geom, 2)) |
+            | W        | 20     | ST_LineString         | 1, 2, 3                          | NULL                             |
+            | W        | 21     | ST_LineString         | 4, 5, 6                          | NULL                             |
+            | R        | 30     | ST_LineString         | 1, 2, 3                          | NULL                             |
+            | R        | 31     | ST_MultiLineString    | 1, 2, 3                          | 4, 5, 6                          |
+

tests/bdd/flex/geometry-processing.feature

@@ -74,7 +74,7 @@ Feature: Tests for Lua geometry processing functions
                     geomsimple = object:as_linestring():simplify(0.1)
                 })
 
-                local g = object:as_polygon()
+                local g = object:as_multipolygon()
                 tables.polygons:insert({
                     name = object.tags.name,
                     geom = g,