connection: Add BackgroundCommand.__init__(conn)

Add a constructor to BackgroundCommand so that the command knows the
connection it's tied to.

devlib/connection.py

@@ -120,6 +120,10 @@ class BackgroundCommand(ABC):
     Instances of this class can be used as context managers, with the same
     semantic as :class:`subprocess.Popen`.
     """
+
+    def __init__(self, conn):
+        self.conn = conn
+
     @abstractmethod
     def send_signal(self, sig):
         """
@@ -235,7 +239,8 @@ class PopenBackgroundCommand(BackgroundCommand):
     :class:`subprocess.Popen`-based background command.
     """
 
-    def __init__(self, popen):
+    def __init__(self, conn, popen):
+        super().__init__(conn=conn)
         self.popen = popen
 
     def send_signal(self, sig):
@@ -291,9 +296,9 @@ class ParamikoBackgroundCommand(BackgroundCommand):
     :mod:`paramiko`-based background command.
     """
     def __init__(self, conn, chan, pid, as_root, cmd, stdin, stdout, stderr, redirect_thread):
+        super().__init__(conn=conn)
         self.chan = chan
         self.as_root = as_root
-        self.conn = conn
         self._pid = pid
         self._stdin = stdin
         self._stdout = stdout
@@ -454,7 +459,7 @@ class AdbBackgroundCommand(BackgroundCommand):
     """
 
     def __init__(self, conn, adb_popen, pid, as_root):
-        self.conn = conn
+        super().__init__(conn=conn)
         self.as_root = as_root
         self.adb_popen = adb_popen
         self._pid = pid

devlib/host.py

@@ -141,7 +141,7 @@ class LocalConnection(ConnectionBase):
             shell=True,
             preexec_fn=preexec_fn,
         )
-        bg_cmd = PopenBackgroundCommand(popen)
+        bg_cmd = PopenBackgroundCommand(self, popen)
         self._current_bg_cmds.add(bg_cmd)
         return bg_cmd
 

devlib/utils/android.py

@@ -334,7 +334,12 @@ class AdbConnection(ConnectionBase):
             adb_command(self.device, command, timeout=timeout, adb_server=self.adb_server)
         else:
             with self.transfer_mgr.manage(sources, dest, action):
-                bg_cmd = adb_command_background(self.device, command, adb_server=self.adb_server)
+                bg_cmd = adb_command_background(
+                    device=self.device,
+                    conn=self,
+                    command=command,
+                    adb_server=self.adb_server
+                )
                 self.transfer_mgr.set_transfer_and_wait(bg_cmd)
 
     # pylint: disable=unused-argument
@@ -692,11 +697,11 @@ def adb_command(device, command, timeout=None, adb_server=None):
     return output
 
 
-def adb_command_background(device, command, adb_server=None):
+def adb_command_background(device, conn, command, adb_server=None):
     full_command = get_adb_command(device, command, adb_server)
     logger.debug(full_command)
-    proc = get_subprocess(full_command, shell=True)
-    cmd = PopenBackgroundCommand(proc)
+    popen = get_subprocess(full_command, shell=True)
+    cmd = PopenBackgroundCommand(conn=conn, popen=popen)
     return cmd