twisted/internet/_baseprocess.py

   1 # -*- test-case-name: twisted.test.test_process -*-
   2 # Copyright (c) Twisted Matrix Laboratories.
   3 # See LICENSE for details.
   4
   5 """
   6 Cross-platform process-related functionality used by different
   7 L{IReactorProcess} implementations.
   8 """
   9
  10 from twisted.python.reflect import qual
  11 from twisted.python.deprecate import getWarningMethod
  12 from twisted.python.failure import Failure
  13 from twisted.python.log import err
  14 from twisted.persisted.styles import Ephemeral
  15
  16 _missingProcessExited = ("Since Twisted 8.2, IProcessProtocol.processExited "
  17                          "is required.  %s must implement it.")
  18
  19 class BaseProcess(Ephemeral):
  20     pid = None
  21     status = None
  22     lostProcess = 0
  23     proto = None
  24
  25     def __init__(self, protocol):
  26         self.proto = protocol
  27
  28
  29     def _callProcessExited(self, reason):
  30         default = object()
  31         processExited = getattr(self.proto, 'processExited', default)
  32         if processExited is default:
  33             getWarningMethod()(
  34                 _missingProcessExited % (qual(self.proto.__class__),),
  35                 DeprecationWarning, stacklevel=0)
  36         else:
  37             processExited(Failure(reason))
  38
  39
  40     def processEnded(self, status):
  41         """
  42         This is called when the child terminates.
  43         """
  44         self.status = status
  45         self.lostProcess += 1
  46         self.pid = None
  47         self._callProcessExited(self._getReason(status))
  48         self.maybeCallProcessEnded()
  49
  50
  51     def maybeCallProcessEnded(self):
  52         """
  53         Call processEnded on protocol after final cleanup.
  54         """
  55         if self.proto is not None:
  56             reason = self._getReason(self.status)
  57             proto = self.proto
  58             self.proto = None
  59             try:
  60                 proto.processEnded(Failure(reason))
  61             except:
  62                 err(None, "unexpected error in processEnded")