Take advantage of MountFS.close(), allow turning auto_mount off.

fs/contrib/archivefs.py

@@ -195,15 +195,15 @@ class ArchiveFS(FS):
 class ArchiveMountFS(mountfs.MountFS):
     '''A subclass of MountFS that automatically identifies archives. Once identified
     archives are mounted in place of the archive file.'''
-    def __init__(self, rootfs, **kwargs):
-        super(ArchiveMountFS, self).__init__(**kwargs)
+    def __init__(self, rootfs, auto_mount=True):
+        self.auto_mount = auto_mount
+        super(ArchiveMountFS, self).__init__(auto_close=True)
         self.rootfs = rootfs
         self.mountdir('/', rootfs)
 
     def __del__(self):
-        # Umount everything that we mounted.
-        for mountpoint in self.mount_tree.keys():
-            self.unmount(mountpoint)
+        # Close automatically.
+        self.close()
 
     def ismount(self, path):
         try:
@@ -213,6 +213,7 @@ class ArchiveMountFS(mountfs.MountFS):
         return type(object) is mountfs.MountFS.DirMount
 
     def _delegate(self, path):
+        if self.auto_mount:
             for ppath in recursepath(path)[1:]:
                 # Don't mount again...
                 if self.ismount(ppath):