Refactor tools subpackage (part 3 of #749). (#753)

* Update `_write_structbody_size_assertion`.

* Update `tools/tlbparser.py`.

* Add `_write_structbody_size_comments`.

* Improve import part of `tools/tlbparser.py`.

comtypes/tools/codegenerator/codegenerator.py

@@ -440,36 +440,33 @@ def StructureBody(self, body: typedesc.StructureBody) -> None:
 
             if body.struct.size is None:
                 with self.adjust_blank("comment") as ofi:
-                    msg1 = "# The size provided by the typelib is incorrect."
-                    msg2 = (
-                        "# The size and alignment check "
-                        f"for {body.struct.name} is skipped."
-                    )
-                    print(msg1, file=ofi)
-                    print(msg2, file=ofi)
+                    self._write_structbody_size_comments(body, ofi)
             elif body.struct.name not in packing.dont_assert_size:
                 with self.adjust_blank("assert") as ofi:
                     self._write_structbody_size_assertion(body, ofi)
 
-        if not methods:
-            return
-        self.imports.add("comtypes", "COMMETHOD")
-        with self.adjust_blank("attribute") as ofi:
-            self._write_structbody_commethods(body, methods, ofi)
+        if methods:
+            self.imports.add("comtypes", "COMMETHOD")
+            with self.adjust_blank("attribute") as ofi:
+                self._write_structbody_commethods(body, methods, ofi)
+
+    def _write_structbody_size_comments(
+        self, body: typedesc.StructureBody, ofi: io.StringIO
+    ) -> None:
+        msg1 = "# The size provided by the typelib is incorrect."
+        msg2 = f"# The size and alignment check for {body.struct.name} is skipped."
+        print(msg1, file=ofi)
+        print(msg2, file=ofi)
 
     def _write_structbody_size_assertion(
         self, body: typedesc.StructureBody, ofi: io.StringIO
     ) -> None:
+        name = body.struct.name
+        assert body.struct.size is not None
         size = body.struct.size // 8
-        print(
-            f"assert sizeof({body.struct.name}) == {size}, sizeof({body.struct.name})",
-            file=ofi,
-        )
+        print(f"assert sizeof({name}) == {size}, sizeof({name})", file=ofi)
         align = body.struct.align // 8
-        print(
-            f"assert alignment({body.struct.name}) == {align}, alignment({body.struct.name})",
-            file=ofi,
-        )
+        print(f"assert alignment({name}) == {align}, alignment({name})", file=ofi)
 
     def _write_structbody_commethods(
         self,

comtypes/tools/tlbparser.py

@@ -1,13 +1,11 @@
 import os
 import sys
-from typing import Any
-from typing import Dict, List, Optional, Tuple
 from ctypes import alignment, byref, c_void_p, sizeof, windll
+from typing import Any, Dict, List, Optional, Tuple
 
-from comtypes import automation, BSTR, COMError, typeinfo
-from comtypes.tools import typedesc
+from comtypes import BSTR, COMError, automation, typeinfo
 from comtypes.client._code_cache import _get_module_filename
-
+from comtypes.tools import typedesc
 
 # Is the process 64-bit?
 is_64bits = sys.maxsize > 2**32
@@ -237,7 +235,7 @@ def ParseModule(self, tinfo: typeinfo.ITypeInfo, ta: typeinfo.TYPEATTR) -> None:
             elif fd.callconv == typeinfo.CC_STDCALL:
                 attributes = "__stdcall__"
             else:
-                raise ValueError("calling convention %d" % fd.callconv)
+                raise ValueError(f"calling convention {fd.callconv:d}")
 
             func = typedesc.Function(func_name, returns, attributes, extern=1)
             if func_doc is not None: