rules: uinput: Only sleep if two events are really close to each other

Several sleep points exist to serialize keyboard and mouse events.
However, these unconditional sleeps hurt the performance as they block
the main thread.

Postpone sleep until the next event, and skip it if enough time has
elapsed.

Signed-off-by: Rongrong <i@rong.moe>

lib/logitech_receiver/diversion.py

@@ -257,6 +257,22 @@ else:
 class UInput:
     def __init__(self):
         self.udevice = None
+        self.barrier_until = None
+
+    def _wait_barrier(self):
+        if self.barrier_until is None:
+            return
+
+        remainder = self.barrier_until - time.monotonic()
+        if remainder > 0:
+            if logger.isEnabledFor(logging.DEBUG):
+                logger.debug("wait %.3fs due to barrier", remainder)
+            time.sleep(remainder)
+
+        self.barrier_until = None
+
+    def barrier(self, margin: float):
+        self.barrier_until = time.monotonic() + margin
 
     def setup(self):
         if self.udevice is not None:
@@ -285,8 +301,10 @@ class UInput:
                 logger.warning("uinput write failed: %s", e)
 
     def key(self, code, event):  # X11 keycode but Solaar event code
-        if evdev and self.simulate(evdev.ecodes.EV_KEY, code - 8, event):
-            return True
+        if evdev:
+            self._wait_barrier()
+            if self.simulate(evdev.ecodes.EV_KEY, code - 8, event):
+                return True
         logger.warning("no way to simulate key input")
 
     def _click(self, button, count):
@@ -306,12 +324,14 @@ class UInput:
         return True
 
     def click(self, button, count):
+        self._wait_barrier()
         if self._click(button, count):
             return True
         logger.warning("no way to simulate mouse click")
         return False
 
     def scroll(self, dx, dy):
+        self._wait_barrier()
         success = True
         if dx:
             success = self.simulate(evdev.ecodes.EV_REL, evdev.ecodes.REL_HWHEEL, dx)
@@ -1210,7 +1230,7 @@ class KeyPress(Action):
                 self.keyDown(self.key_symbols, current)
             if self.action != DEPRESS:
                 self.keyUp(reversed(self.key_symbols), current)
-            time.sleep(0.01)
+            uinput.barrier(0.01)
         else:
             logger.warning("no keymap so cannot determine which keycode to send")
         return None
@@ -1249,7 +1269,7 @@ class MouseScroll(Action):
             logger.info("MouseScroll action: %s %s %s", self.amounts, last_result, amounts)
         dx, dy = amounts
         uinput.scroll(dx, dy)
-        time.sleep(0.01)
+        uinput.barrier(0.01)
         return None
 
     def data(self):
@@ -1288,7 +1308,7 @@ class MouseClick(Action):
             logger.info(f"MouseClick action: {str(self.count)} {self.button}")
         if self.button and self.count:
             uinput.click(buttons[self.button], self.count)
-        time.sleep(0.01)
+        uinput.barrier(0.01)
         return None
 
     def data(self):