replace classes FuseMount & EncFSMount with functions chdir, fuse_mount & encfs_mount

rc.xsh

@@ -30,6 +30,7 @@ $PROMPT = ''.join([
 $RIGHT_PROMPT = '{gitstatus}{env_name: {}}'
 $XONSH_APPEND_NEWLINE = True
 
+import contextlib
 import datetime as dt
 import io
 import os
@@ -139,43 +140,6 @@ class DockerImage:
         sys.stderr.write('{}\n'.format(shlex_join(params)))
         subprocess.run(params, check=True)
 
-class FuseMount:
-
-    def __init__(self, mount_arg_patterns, mount_point_path, cd=False):
-        self._mount_arg_patterns = mount_arg_patterns
-        self._mount_point_path = mount_point_path
-        self._cd = cd
-
-    def __enter__(self):
-        import shlex
-        mount_args = [a.format(mp=shlex.quote(self._mount_point_path))
-                      for a in self._mount_arg_patterns]
-        sys.stderr.write('{}\n'.format(shlex_join(mount_args)))
-        subprocess.check_call(mount_args)
-        if self._cd:
-            self._previous_work_dir_path = os.getcwd()
-            os.chdir(self._mount_point_path)
-        return self._mount_point_path
-
-    def __exit__(self, exc_type, exc_value, traceback):
-        umount_args = ['fusermount', '-u', '-z', self._mount_point_path]
-        sys.stderr.write('{}\n'.format(shlex_join(umount_args)))
-        subprocess.check_call(umount_args)
-        if self._cd:
-            os.chdir(self._previous_work_dir_path)
-
-class EncFSMount(FuseMount):
-
-    def __init__(self, root_dir_path, mount_point_path, cd=False, extpass=None):
-        mount_arg_patterns = ['encfs', root_dir_path, mount_point_path]
-        if extpass:
-            mount_arg_patterns.extend(['--extpass', shlex_join(extpass)])
-        super().__init__(
-            mount_arg_patterns=mount_arg_patterns,
-            mount_point_path=mount_point_path,
-            cd=cd,
-        )
-
 class StdoutTee:
 
     def __init__(self, sink):
@@ -207,6 +171,15 @@ class StdoutTee:
         os.close(self._write_fd)
         self._thread.join()
 
+@contextlib.contextmanager
+def chdir(path):
+    previous = os.getcwd()
+    try:
+        os.chdir(path)
+        yield path
+    finally:
+        os.chdir(previous)
+
 def dpkg_listfiles(pkg_name):
     assert isinstance(pkg_name, str)
     paths = $(dpkg --listfiles @(pkg_name)).split('\n')[:-1]
@@ -233,6 +206,29 @@ def dpkg_which(cmd):
     assert len(matches) == 1
     return matches[0]
 
+@contextlib.contextmanager
+def encfs_mount(root_dir_path, mount_point_path, extpass=None):
+    mount_arg_patterns = ['encfs', root_dir_path, mount_point_path]
+    if extpass:
+        mount_arg_patterns.extend(['--extpass', shlex_join(extpass)])
+    with fuse_mount(mount_arg_patterns=mount_arg_patterns,
+                    mount_point_path=mount_point_path):
+        yield mount_point_path
+
+@contextlib.contextmanager
+def fuse_mount(mount_arg_patterns, mount_point_path):
+    import shlex
+    mount_args = [a.format(mp=shlex.quote(mount_point_path))
+                  for a in mount_arg_patterns]
+    sys.stderr.write('{}\n'.format(shlex_join(mount_args)))
+    subprocess.check_call(mount_args)
+    try:
+        yield mount_point_path
+    finally:
+        umount_args = ['fusermount', '-u', '-z', mount_point_path]
+        sys.stderr.write('{}\n'.format(shlex_join(umount_args)))
+        subprocess.check_call(umount_args)
+
 def gpg_decrypt(path, verify=False):
     import gpg
     with gpg.Context() as gpg_ctx: