ThrottledDevice: speed up quick reactivation

[~helmut/onoff.git] / onoff / common.py

diff --git a/onoff/common.py b/onoff/common.py
index 7f389c9..4a1fe8c 100644 (file)
--- a/onoff/common.py
+++ b/onoff/common.py
@@ -1,9 +1,9 @@
 """
 Defined states:
- * 0: The device is inactive.
- * ST_ACTIVE|ST_TRANSITION: The device is transitioning from inactive to active.
- * ST_ACTIVE: The device is active.
- * ST_TRANSITION: The device is transitioning from active to inactive.
+ - 0: The device is inactive.
+ - ST_ACTIVE|ST_TRANSITION: The device is transitioning from inactive to active.
+ - ST_ACTIVE: The device is active.
+ - ST_TRANSITION: The device is transitioning from active to inactive.
 """
 
 import logging
@@ -73,50 +73,103 @@ class InvertedDevice(OnoffDevice):
         self.device.close()
 
 class ThrottledDevice(OnoffDevice):
-    """A device that delays deactivation by a fixed amount of time. This limits
-    the rate of state transitions to two per delay."""
-    def __init__(self, device, delay):
+    """A device that delays the activation signal and the actual deactivation
+    by a fixed amounts of time. This limits the rate of state transitions to
+    two per offdelay."""
+    def __init__(self, device, ondelay, offdelay):
         """
         @type device: OnoffDevice
-        @type delay: int or float
-        @param delay: deactivation delay in seconds
+        @type ondelay: int or float
+        @param ondelay: delay the report of ST_ACTIVE by this many seconds
+        @type offdelay: int or float
+        @param offdelay: delay the actual deactivation by this many seconds
         """
         OnoffDevice.__init__(self)
         self.device = device
-        self.delay = delay
+        self.ondelay = ondelay
+        self.offdelay = offdelay
         self.desired_state = 0
-        self.stopping = None
+        self.transition = None
         self.device.notify.add(self.changestate)
 
     @property
     def state(self):
-        return self.device.state | (ST_TRANSITION if self.stopping else 0)
+        if self.transition is None:
+            return self.device.state
+        return self.desired_state | ST_TRANSITION
+
+    def _schedule_transition(self, delay, func):
+        assert self.transition is None
+        self.transition = GObject.timeout_add(int(1000 * delay), func)
+
+    def _cancel_transition(self):
+        assert self.transition is not None
+        ret = GObject.source_remove(self.transition)
+        assert ret
+        self.transition = None
+
+    def changestate(self, state):
+        if state != ST_ACTIVE:
+            OnoffDevice.changestate(self, state)
+        else:
+            if self.desired_state == 0:
+                logger.warn("device became active but we want inactive," +
+                            "suppresing signal")
+            elif self.transition is None:
+                logger.debug("scheduling report of activation in %.1fs",
+                             self.ondelay)
+                self._schedule_transition(self.ondelay, self._report_active)
+            else:
+                logger.debug("suppressing duplicate activation signal")
+
+    def _report_active(self):
+        assert self.desired_state == ST_ACTIVE
+        assert self.transition is not None
+        self.transition = None
+        logger.debug("delivering activation signal")
+        OnoffDevice.changestate(self, ST_ACTIVE)
 
     def activate(self):
-        self.desired_state = ST_ACTIVE
-        if self.stopping is not None:
+        if self.desired_state == 0 and self.transition is not None:
             logger.debug("cancelling pending deactivation")
-            ret = GObject.source_remove(self.stopping)
-            assert ret
-            self.stopping = None
+            self._cancel_transition()
+            curstate = self.device.state
+            if curstate == ST_ACTIVE:
+                self.desired_state = ST_ACTIVE
+                OnoffDevice.changestate(self, ST_ACTIVE)
+                return
+            logger.warn("device should be active during delayed deactivation" +
+                        ", but is in state %d", curstate)
+        self.desired_state = ST_ACTIVE
         self.device.activate()
+        self.changestate(self.device.state)
 
-    def do_stop(self):
+    def _do_stop(self):
         assert self.desired_state == 0
-        assert self.stopping is not None
-        self.stopping = None
+        assert self.transition is not None
+        self.transition = None
         logger.debug("actually deactivating")
         self.device.deactivate()
 
     def deactivate(self):
+        if self.desired_state == ST_ACTIVE and self.transition is not None:
+            logger.debug("cancelling pending activation report")
+            self._cancel_transition()
         self.desired_state = 0
-        if self.stopping is None:
-            logger.debug("scheduling actual deactivate in %.1fs", self.delay)
-            self.stopping = GObject.timeout_add(1000 * self.delay, self.do_stop)
+        if self.transition is None:
+            logger.debug("scheduling actual deactivate in %.1fs",
+                         self.offdelay)
+            self._schedule_transition(self.offdelay, self._do_stop)
             self.changestate(self.state)
         else:
             logger.debug("not issuing deactivate due to pending deactivate")
 
     def close(self):
+        if self.transition is not None:
+            logger.info("cancelling pending transition")
+            self._cancel_transition()
+            if self.desired_state == 0:
+                logger.info("invoking pending deactivate early during close")
+                self.device.deactivate()
         self.device.notify.remove(self.changestate)
         self.device.close()