add i2c sensors

custom_components/mega/tools.py

@@ -1,3 +1,9 @@
+import asyncio
+import itertools
+from heapq import heappush
+from contextlib import asynccontextmanager
+
+
 _params = ['m', 'click', 'cnt', 'pt']
 
 
@@ -17,4 +23,95 @@ def int_ignore(x):
     try:
         return int(x)
     except (TypeError, ValueError):
-        return x
+        return x
+
+
+class PriorityLock(asyncio.Lock):
+    """
+    You can acquire lock with some kind of priority in mind, so that locks with higher priority will be released first.
+    priority can be set with lck.acquire(1)
+    or by using context manager:
+    >>> lck = PriorityLock()
+    ... async with lck(1):
+    ...     # do something
+    """
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self._cnt = itertools.count()
+
+    def __call__(self, priority=0):
+        return self._with_priority(priority)
+
+    @asynccontextmanager
+    async def _with_priority(self, p):
+        await self.acquire(p)
+        try:
+            yield
+        finally:
+            self.release()
+
+    async def acquire(self, priority=0) -> bool:
+        """Acquire a lock.
+
+                This method blocks until the lock is unlocked, then sets it to
+                locked and returns True.
+                """
+        if (not self._locked and (self._waiters is None or
+                                  all(w.cancelled() for _, w in self._waiters))):
+            self._locked = True
+            return True
+
+        if self._waiters is None:
+            self._waiters = []
+
+        fut = self._loop.create_future()
+        cnt = next(self._cnt)
+        heappush(self._waiters, (priority, cnt, fut))
+
+        # Finally block should be called before the CancelledError
+        # handling as we don't want CancelledError to call
+        # _wake_up_first() and attempt to wake up itself.
+        try:
+            try:
+                await fut
+            finally:
+                self._waiters.remove((priority, cnt, fut))
+        except asyncio.exceptions.CancelledError:
+            if not self._locked:
+                self._wake_up_first()
+            raise
+
+        self._locked = True
+        return True
+
+    def release(self):
+        """Release a lock.
+
+        When the lock is locked, reset it to unlocked, and return.
+        If any other coroutines are blocked waiting for the lock to become
+        unlocked, allow exactly one of them to proceed.
+
+        When invoked on an unlocked lock, a RuntimeError is raised.
+
+        There is no return value.
+        """
+        if self._locked:
+            self._locked = False
+            self._wake_up_first()
+        else:
+            raise RuntimeError('Lock is not acquired.')
+
+    def _wake_up_first(self):
+        """Wake up the first waiter if it isn't done."""
+        if not self._waiters:
+            return
+        try:
+            _, _, fut = self._waiters[0]
+        except IndexError:
+            return
+
+        # .done() necessarily means that a waiter will wake up later on and
+        # either take the lock, or, if it was cancelled and lock wasn't
+        # taken already, will hit this again and wake up a new waiter.
+        if not fut.done():
+            fut.set_result(True)