python/qemu: make 'args' style arguments immutable
These arguments don't need to be mutable and aren't really used as
such. Clarify their types as immutable and adjust code to match where
necessary.
In general, It's probably best not to accept a user-defined mutable
object and store it as internal object state unless there's a strong
justification for doing so. Instead, try to use generic types as input
with empty tuples as the default, and coerce to list where necessary.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20201006235817.3280413-10-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
diff --git a/python/qemu/machine.py b/python/qemu/machine.py
index 4e762fc..e599cb7 100644
--- a/python/qemu/machine.py
+++ b/python/qemu/machine.py
@@ -18,6 +18,7 @@
#
import errno
+from itertools import chain
import logging
import os
import shutil
@@ -30,6 +31,8 @@
Dict,
List,
Optional,
+ Sequence,
+ Tuple,
Type,
)
@@ -74,8 +77,12 @@
# vm is guaranteed to be shut down here
"""
- def __init__(self, binary, args=None, wrapper=None, name=None,
- test_dir="/var/tmp",
+ def __init__(self,
+ binary: str,
+ args: Sequence[str] = (),
+ wrapper: Sequence[str] = (),
+ name: Optional[str] = None,
+ test_dir: str = "/var/tmp",
monitor_address: Optional[SocketAddrT] = None,
socket_scm_helper=None, sock_dir=None,
drain_console=False, console_log=None):
@@ -97,14 +104,7 @@
# Direct user configuration
self._binary = binary
-
- if args is None:
- args = []
- # Copy mutable input: we will be modifying our copy
self._args = list(args)
-
- if wrapper is None:
- wrapper = []
self._wrapper = wrapper
self._name = name or "qemu-%d" % os.getpid()
@@ -136,7 +136,7 @@
self._iolog = None
self._qmp_set = True # Enable QMP monitor by default.
self._qmp_connection: Optional[qmp.QEMUMonitorProtocol] = None
- self._qemu_full_args = None
+ self._qemu_full_args: Tuple[str, ...] = ()
self._temp_dir = None
self._launched = False
self._machine = None
@@ -368,7 +368,7 @@
raise QEMUMachineError('VM already launched')
self._iolog = None
- self._qemu_full_args = None
+ self._qemu_full_args = ()
try:
self._launch()
self._launched = True
@@ -388,8 +388,12 @@
"""
devnull = open(os.path.devnull, 'rb')
self._pre_launch()
- self._qemu_full_args = (self._wrapper + [self._binary] +
- self._base_args + self._args)
+ self._qemu_full_args = tuple(
+ chain(self._wrapper,
+ [self._binary],
+ self._base_args,
+ self._args)
+ )
LOG.debug('VM launch command: %r', ' '.join(self._qemu_full_args))
self._popen = subprocess.Popen(self._qemu_full_args,
stdin=devnull,
diff --git a/python/qemu/qtest.py b/python/qemu/qtest.py
index 7fde256..675310d 100644
--- a/python/qemu/qtest.py
+++ b/python/qemu/qtest.py
@@ -19,7 +19,12 @@
import os
import socket
-from typing import List, Optional, TextIO
+from typing import (
+ List,
+ Optional,
+ Sequence,
+ TextIO,
+)
from .machine import QEMUMachine
@@ -99,8 +104,13 @@
A QEMU VM, with a qtest socket available.
"""
- def __init__(self, binary, args=None, name=None, test_dir="/var/tmp",
- socket_scm_helper=None, sock_dir=None):
+ def __init__(self,
+ binary: str,
+ args: Sequence[str] = (),
+ name: Optional[str] = None,
+ test_dir: str = "/var/tmp",
+ socket_scm_helper: Optional[str] = None,
+ sock_dir: Optional[str] = None):
if name is None:
name = "qemu-%d" % os.getpid()
if sock_dir is None:
@@ -114,8 +124,10 @@
@property
def _base_args(self) -> List[str]:
args = super()._base_args
- args.extend(['-qtest', 'unix:path=' + self._qtest_path,
- '-accel', 'qtest'])
+ args.extend([
+ '-qtest', f"unix:path={self._qtest_path}",
+ '-accel', 'qtest'
+ ])
return args
def _pre_launch(self):
