plan9.filesystem: Inode context manager protocol

provide context manager protocol for Inode objects in order
to simplify callback registration code blocks

Author: svinota

pyroute2/fixtures/plan9.py

@@ -24,11 +24,11 @@ def __init__(self):
         self.server = Plan9ServerSocket(use_socket=self.server_sock)
         self.client = Plan9ClientSocket(use_socket=self.client_sock)
         self._task = None
-        inode_static = self.server.filesystem.create('test_file')
-        inode_static.data.write(self.sample_data)
-        inode_dynamic = self.server.filesystem.create('test_time')
-        inode_dynamic.metadata.call_on_read = True
-        inode_dynamic.register_function(test_time, loader=lambda x: {})
+        with self.server.filesystem.create('test_file') as i:
+            i.data.write(self.sample_data)
+        with self.server.filesystem.create('test_time') as i:
+            i.metadata.call_on_read = True
+            i.register_function(test_time, loader=lambda x: {})
 
     async def ensure_session(self):
         self._task = await self.server.async_run()

pyroute2/plan9/filesystem.py

@@ -118,6 +118,12 @@ def __init__(
         self.stat['name'] = name
         self.sync()
 
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        pass
+
     def sync(self):
         self.stat['length'] = len(self.data.getvalue())