add the move_dir optimization

Author: tfeldmann

fs/move.py

@@ -5,14 +5,15 @@
 
 import typing
 
-import shutil
+import os
 
 from ._pathcompat import commonpath
 from .copy import copy_dir, copy_file
-from .errors import FSError
+from .error_tools import convert_os_errors
+from .errors import DirectoryExpected, FSError, IllegalDestination, ResourceNotFound
 from .opener import manage_fs
 from .osfs import OSFS
-from .path import frombase
+from .path import frombase, isbase
 
 if typing.TYPE_CHECKING:
     from typing import Text, Union
@@ -139,13 +140,24 @@ def move_dir(
     """
     with manage_fs(src_fs, writeable=True) as _src_fs:
         with manage_fs(dst_fs, writeable=True, create=True) as _dst_fs:
+            if not _src_fs.exists(src_path):
+                raise ResourceNotFound(src_path)
+            if not _src_fs.isdir(src_path):
+                raise DirectoryExpected(src_path)
 
-            # if both filesystems have a syspath we can use shutil to move the folder
+            # if both filesystems have a syspath we use `os.rename` to move the folder
             if _src_fs.hassyspath(src_path) and _dst_fs.hassyspath(dst_path):
                 src_syspath = _src_fs.getsyspath(src_path)
                 dst_syspath = _dst_fs.getsyspath(dst_path)
+                # recheck if the move operation is legal using the syspaths
+                if isbase(src_syspath, dst_syspath):
+                    raise IllegalDestination(dst_path)
                 with _src_fs.lock(), _dst_fs.lock():
-                    shutil.move(src=src_syspath, dst=dst_syspath)
+                    with convert_os_errors("move_dir", src_path, directory=True):
+                        os.rename(src=src_syspath, dst=dst_syspath)
+                        # recreate the root dir if it has been renamed
+                        if src_path == "/":
+                            _src_fs.makedir("/")
                     return  # optimization worked, exit early
 
             # standard copy then delete