ycmd watchog timer now wiser about machine sleep

We now make sure we don't terminate ycmd if we skipped a watchdog wakeup
time. If we skipped a check, that means the machine probably went to sleep and
the client might still actually be up. In such cases, we give it one more wait
interval to contact us before we die.

python/ycm/server/watchdog_plugin.py

@@ -44,6 +44,10 @@ class WatchdogPlugin( object ):
                 check_interval_seconds = 60 * 10 ):
     self._check_interval_seconds = check_interval_seconds
     self._idle_suicide_seconds = idle_suicide_seconds
+
+    # No need for a lock on wakeup time since only the watchdog thread ever
+    # reads or sets it.
+    self._last_wakeup_time = time.time()
     self._last_request_time = time.time()
     self._last_request_time_lock = Lock()
     if idle_suicide_seconds <= 0:
@@ -63,12 +67,32 @@ class WatchdogPlugin( object ):
       self._last_request_time = new_value
 
 
+  def _TimeSinceLastRequest( self ):
+    return time.time() - self._GetLastRequestTime()
+
+
+  def _TimeSinceLastWakeup( self ):
+    return time.time() - self._last_wakeup_time()
+
+
+  def _UpdateLastWakeupTime( self ):
+    self._last_wakeup_time = time.time()
+
+
   def _WatchdogMain( self ):
     while True:
       time.sleep( self._check_interval_seconds )
-      if time.time() - self._GetLastRequestTime() > self._idle_suicide_seconds:
+
+      # We make sure we don't terminate if we skipped a wakeup time. If we
+      # skipped a check, that means the machine probably went to sleep and the
+      # client might still actually be up. In such cases, we give it one more
+      # wait interval to contact us before we die.
+      if (self._TimeSinceLastRequest() > self._idle_suicide_seconds and
+          self._TimeSinceLastWakeup() < 2 * self._check_interval_seconds):
         utils.TerminateProcess( os.getpid() )
 
+      self._UpdateLastWakeupTime()
+
 
   def __call__( self, callback ):
     def wrapper( *args, **kwargs ):