added SyncScheduler

Author: semiversus

src/durand/scheduler.py

@@ -4,6 +4,7 @@
 from typing import Callable, Tuple, TypeVar, Dict, Any
 import functools
 import threading
+from sched import scheduler
 
 
 TEntry = TypeVar("TEntry")  # type of scheduler entry
@@ -25,12 +26,9 @@ def add(self, delay: float, callback, args=(), kwargs=None) -> TEntry:
     def cancel(self, entry: TEntry):
         """Cancel a scheduled callback
 
-        :param entry: the scheduler entry to be canceld
+        :param entry: the scheduler entry to be canceled
         """
 
-    def start(self):
-        """Start scheduling"""
-
     @abstractproperty
     def lock(self):
         """A global lock which can be used the assure thread safety"""
@@ -57,6 +55,34 @@ def lock(self):
         return self._lock
 
 
+class SyncScheduler(AbstractScheduler):
+    def __init__(self, lock: threading.Lock=None):
+        if lock is None:
+            lock = threading.Lock()
+        self._lock = lock
+        self._sched = scheduler()
+        self._wake_up = threading.Event()
+
+    def add(self, delay: float, callback, args=(), kwargs=None) -> asyncio.TimerHandle:
+        if kwargs == None:
+            kwargs = {}
+        self._wake_up.set()
+        return self._sched.enter(delay, 0, callback, args, kwargs)
+
+    def cancel(self, entry):
+        self._sched.cancel(entry)
+
+    def run(self):
+        while True:
+            self._sched.run()
+            self._wake_up.wait()
+            self._wake_up.clear()
+
+    @property
+    def lock(self):
+        return self._lock
+
+
 class VirtualScheduler(AbstractScheduler):
     @dataclass
     class Entry: