我有一个包含类的
python脚本.
这个类有一个__del__方法用于常规清理.如果我在正常执行脚本期间删除了类,我想要完成一些清理工作.
我也有一个信号处理程序,它做了一些不寻常的清理工作.如果脚本在收到信号时正在执行其他操作,则需要进行一些额外的清理,然后进行常规清理.
我注意到做del self和self .__ del __()之间有区别.
也就是说,self .__ del __()调用del方法两次.
你能解释一下为什么会这样吗?
这是一个模拟脚本来说明问题:
import sys import signal from optparse import OptionParser class TestClass(object): def __init__(self,del_self): self.del_self = del_self print "__init__ with del_self = %s" % self.del_self def __del__(self): print "Now performing usual cleanup." def signal_handler(self,arg_1,arg_2): print "Received signal. Now performing unusual cleanup." # Unusual cleanup print "Did unusual cleanup" if self.del_self: print("Doing del self") del self else: print("Doing self.__del__()") self.__del__() sys.exit(0) if __name__ == '__main__': arguments = sys.argv[1:] parse = OptionParser("Test.") parse.add_option( "-d","--delself",help="Set del self.",type="int",default=1 ) (options,_) = parse.parse_args() print "Options: %s" % options tc = TestClass(del_self=options.delself) signal.signal(signal.SIGQUIT,tc.signal_handler) while True: pass
如果我运行脚本:
python deltest.py --delself 1
并发出killall -3 python我得到:
Received signal. Now performing unusual cleanup. Did unusual cleanup Doing del self Now performing usual cleanup.
在哪里,如果我再次执行python deltest.py –delself 0后跟kill信号,我得到:
Received signal. Now performing unusual cleanup. Did unusual cleanup Doing self.__del__() Now performing usual cleanup. Now performing usual cleanup.
谢谢!