build/android/pylib/utils/watchdog_timer.py

   1 # Copyright 2013 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 """WatchdogTimer timeout objects."""
   6
   7 import time
   8
   9
  10 class WatchdogTimer(object):
  11   """A resetable timeout-based watchdog.
  12
  13   This object is threadsafe.
  14   """
  15
  16   def __init__(self, timeout):
  17     """Initializes the watchdog.
  18
  19     Args:
  20       timeout: The timeout in seconds. If timeout is None it will never timeout.
  21     """
  22     self._start_time = time.time()
  23     self._timeout = timeout
  24
  25   def Reset(self):
  26     """Resets the timeout countdown."""
  27     self._start_time = time.time()
  28
  29   def GetElapsed(self):
  30     """Returns the elapsed time of the watchdog."""
  31     return time.time() - self._start_time
  32
  33   def GetRemaining(self):
  34     """Returns the remaining time of the watchdog."""
  35     if self._timeout:
  36       return self._timeout - self.GetElapsed()
  37     else:
  38       return None
  39
  40   def IsTimedOut(self):
  41     """Whether the watchdog has timed out.
  42
  43     Returns:
  44       True if the watchdog has timed out, False otherwise.
  45     """
  46     remaining = self.GetRemaining()
  47     return remaining is not None and remaining < 0