Added "supports_mtime" meta parameter to file systems.

Author: atollk

fs/base.py

@@ -741,6 +741,8 @@ def getmeta(self, namespace="standard"):
         read_only           `True` if this filesystem is read only.
         supports_rename     `True` if this filesystem supports an
                             `os.rename` operation.
+        supports_mtime      `True` if this filesystem supports a native
+                            operation to retreive the "last modified" time.
         =================== ============================================
 
         Most builtin filesystems will provide all these keys, and third-

fs/ftpfs.py

@@ -707,6 +707,7 @@ def getmeta(self, namespace="standard"):
         if namespace == "standard":
             _meta = self._meta.copy()
             _meta["unicode_paths"] = "UTF8" in self.features
+            _meta["supports_mtime"] = "MDTM" in self.features
         return _meta
 
     def listdir(self, path):

fs/osfs.py

@@ -144,6 +144,7 @@ def __init__(
             "network": False,
             "read_only": False,
             "supports_rename": True,
+            "supports_mtime": True,
             "thread_safe": True,
             "unicode_paths": os.path.supports_unicode_filenames,
             "virtual": False,