Write GlobalId index when serializing to RocksDB

rocks_db_file_storage already exposes a `g|`-prefixed guid -> instance
name map, but RocksDbSerializer never populated it, so by_guid() on a
converted file always threw.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/ifcopenshell-python/test/test_streaming_rocksdb_and_simpletyperefs.py

@@ -115,6 +115,11 @@ def test_rocks():
         b = f.key_value_store_query(f"t|{iden}|0")[1:]
         assert set(struct.unpack("Q", b[i : i + 8])[0] for i in range(1, len(b), 9)) == {136, 138}
 
+        g = ifcopenshell.open(fn)
+        for inst in g.by_type("IfcRoot"):
+            assert f.by_guid(inst.GlobalId).id() == inst.id()
+
+        del g
         del f
         gc.collect()
 

src/serializers/RocksDbSerializer.cpp

@@ -113,6 +113,10 @@ void RocksDbSerializer::write_streaming_() {
 
 	std::string tmp;
 
+	// Resolved lazily from the first non-header declaration encountered, because
+	// the schema is only known once the header has been read.
+	const ifcopenshell::declaration* ifcroot_type = nullptr;
+
 	ifcopenshell::instance_streamer streamer(input_filename_);
 
 	// We do not want to coerce attribute counts here, because we want
@@ -279,6 +283,24 @@ void RocksDbSerializer::write_streaming_() {
 					memcpy(s.data(), &v, sizeof(size_t));
 					storage.db->Merge(storage.wopts, "t|" + std::to_string(decl->index_in_schema()), s);
 				}
+
+				// GlobalId as numeric ref to instance name, so that the guid map in
+				// rocks_db_file_storage can resolve by_guid() lookups.
+				if (ifcroot_type == nullptr) {
+					ifcroot_type = decl->schema()->declaration_by_name("IfcRoot");
+				}
+				if (decl->is(*ifcroot_type)) {
+					// @nb attribute counts are not coerced, so the attribute may be absent
+					const bool has_guid = data->storage_->size() > 0 && data->get_attribute_value(0).type() == ifcopenshell::Argument_STRING;
+					if (has_guid) {
+						size_t v = name;
+						std::string s(sizeof(size_t), ' ');
+						memcpy(s.data(), &v, sizeof(size_t));
+						storage.db->Put(storage.wopts, "g|" + (std::string)data->get_attribute_value(0), s);
+					} else {
+						::logger::root().error("Instance #" + std::to_string(name) + " has no GlobalId, omitted from guid index");
+					}
+				}
 			}
 
 			streamer.references().clear();