1 files changed, 49 insertions, 37 deletions
diff --git a/Lib/posixpath.py b/Lib/posixpath.py
index 195374613a7..a46c667db56 100644
--- a/Lib/posixpath.py
+++ b/Lib/posixpath.py
@@ -334,43 +334,55 @@ def expandvars(path):
 # It should be understood that this may change the meaning of the path
 # if it contains symbolic links!
 
-def normpath(path):
-    """Normalize path, eliminating double slashes, etc."""
-    path = os.fspath(path)
-    if isinstance(path, bytes):
-        sep = b'/'
-        empty = b''
-        dot = b'.'
-        dotdot = b'..'
-    else:
-        sep = '/'
-        empty = ''
-        dot = '.'
-        dotdot = '..'
-    if path == empty:
-        return dot
-    initial_slashes = path.startswith(sep)
-    # POSIX allows one or two initial slashes, but treats three or more
-    # as single slash.
-    # (see http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13)
-    if (initial_slashes and
-        path.startswith(sep*2) and not path.startswith(sep*3)):
-        initial_slashes = 2
-    comps = path.split(sep)
-    new_comps = []
-    for comp in comps:
-        if comp in (empty, dot):
-            continue
-        if (comp != dotdot or (not initial_slashes and not new_comps) or
-             (new_comps and new_comps[-1] == dotdot)):
-            new_comps.append(comp)
-        elif new_comps:
-            new_comps.pop()
-    comps = new_comps
-    path = sep.join(comps)
-    if initial_slashes:
-        path = sep*initial_slashes + path
-    return path or dot
+try:
+    from posix import _path_normpath
+
+except ImportError:
+    def normpath(path):
+        """Normalize path, eliminating double slashes, etc."""
+        path = os.fspath(path)
+        if isinstance(path, bytes):
+            sep = b'/'
+            empty = b''
+            dot = b'.'
+            dotdot = b'..'
+        else:
+            sep = '/'
+            empty = ''
+            dot = '.'
+            dotdot = '..'
+        if path == empty:
+            return dot
+        initial_slashes = path.startswith(sep)
+        # POSIX allows one or two initial slashes, but treats three or more
+        # as single slash.
+        # (see http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13)
+        if (initial_slashes and
+            path.startswith(sep*2) and not path.startswith(sep*3)):
+            initial_slashes = 2
+        comps = path.split(sep)
+        new_comps = []
+        for comp in comps:
+            if comp in (empty, dot):
+                continue
+            if (comp != dotdot or (not initial_slashes and not new_comps) or
+                 (new_comps and new_comps[-1] == dotdot)):
+                new_comps.append(comp)
+            elif new_comps:
+                new_comps.pop()
+        comps = new_comps
+        path = sep.join(comps)
+        if initial_slashes:
+            path = sep*initial_slashes + path
+        return path or dot
+
+else:
+    def normpath(path):
+        """Normalize path, eliminating double slashes, etc."""
+        path = os.fspath(path)
+        if isinstance(path, bytes):
+            return os.fsencode(_path_normpath(os.fsdecode(path))) or b"."
+        return _path_normpath(path) or "."
 
 
 def abspath(path):