Create rename utility function

os.rename() fails on Windows if file already exists.

Create getuid utility function (#21736)

On Windows, replace os.getuid with ctypes.windll.shell32.IsUserAnAdmin().

Tests: Use getuid util function

Co-authored-by: lou.lawrence@kitware.com <lou.lawrence@kitware.com>
Co-authored-by: Betsy McPhail <betsy.mcphail@kitware.com>

lib/spack/llnl/util/filesystem.py

@@ -6,6 +6,7 @@
 import errno
 import glob
 import grp
+import ctypes
 import hashlib
 import itertools
 import numbers
@@ -44,6 +45,7 @@
     'fix_darwin_install_name',
     'force_remove',
     'force_symlink',
+    'getuid',
     'chgrp',
     'chmod_x',
     'copy',
@@ -60,6 +62,7 @@
     'remove_directory_contents',
     'remove_if_dead_link',
     'remove_linked_tree',
+    'rename',
     'set_executable',
     'set_install_permissions',
     'touch',
@@ -71,6 +74,23 @@
 ]
 
 
+def getuid():
+    if _platform == "win32":
+        if ctypes.windll.shell32.IsUserAnAdmin() == 0:
+            return 1
+        return 0
+    else:
+        return os.getuid()
+
+
+def rename(src, dst):
+    # On Windows, os.rename will fail if the destination file already exists
+    if is_windows:
+        if os.path.exists(dst):
+            os.remove(dst)
+    os.rename(src, dst)
+
+
 def path_contains_subdirectory(path, root):
     norm_root = os.path.abspath(root).rstrip(os.path.sep) + os.path.sep
     norm_path = os.path.abspath(path).rstrip(os.path.sep) + os.path.sep
@@ -293,7 +313,7 @@ def group_ids(uid=None):
         (list of int): gids of groups the user is a member of
     """
     if uid is None:
-        uid = os.getuid()
+        uid = getuid()
     user = pwd.getpwuid(uid).pw_name
     return [g.gr_gid for g in grp.getgrall() if user in g.gr_mem]