Make TimeoutRetryThread's stoppable

build/android/pylib/utils/watchdog_timer.py

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """WatchdogTimer timeout objects."""
 
 import time
 
 
 class WatchdogTimer(object):
   """A resetable timeout-based watchdog.
 
   This object is threadsafe.
   """
 
   def __init__(self, timeout):
     """Initializes the watchdog.
 
     Args:
       timeout: The timeout in seconds. If timeout is None it will never timeout.
     """
-    self._start_time = time.time()
     self._timeout = timeout
+    self._start_time = None

[jbudorick, 2014/10/30 02:27:03]

This should still set self._start_time to time.time(). Otherwise, users _have_
to call Reset() before use, which seems counterintuitive.

[perezju, 2014/10/30 18:44:45]

Yeah, I scrapped much of this in the new version.

+    self._end_time = None
+    self.Reset()
 
   def Reset(self):
     """Resets the timeout countdown."""
     self._start_time = time.time()
+    if self._timeout is None:
+      self._end_time = None
+    else:
+      self._end_time = self._start_time + self._timeout
+
+  def ElapsedTime(self):
+    """Returns the number of seconds elapsed since the last reset."""
+    return time.time() - self._start_time
+
+  def RemainingTime(self):
+    """Returns the number of seconds remaining until the watchdog times out."""
+    if self._end_time is None:
+      return None
+    else:
+      return self._end_time - time.time()
 
   def IsTimedOut(self):
     """Whether the watchdog has timed out.
 
     Returns:
       True if the watchdog has timed out, False otherwise.
     """
-    if self._timeout is None:
+    if self._end_time is None:
       return False
-    return time.time() - self._start_time > self._timeout
+    else:
+      return time.time() > self._end_time