Many fixes, many TODOs added

experiment.py

@@ -4,17 +4,17 @@ loop = giambio.EventLoop()
 
 """
 
-What works and what does not (23rd March 2020 23:24 PM)
+What works and what does not (25th March 2020 20:35)
 
 - Run tasks concurrently: V
 - Join mechanism: V
 - Sleep mechanism: V
-- Cancellation mechanism: X  Note: Figure out how to rescheule parent task
+- Cancellation mechanism: V
 - Exception propagation: V
 - Concurrent I/O: V
 - Return values of coroutines: V
 - Scheduling tasks for future execution: V
-- Task Spawner (context manager): X  Note: Not Implemented
+- Task Spawner (context manager): V
 
 """
 
@@ -28,7 +28,7 @@ async def countdown(n):
         return "Count DOWN over"
     except giambio.CancelledError:
         print("countdown cancelled!")
-
+        raise Exception("Oh no!")   #TODO Propagate this
 
 async def count(stop, step=1):
     try:
@@ -44,13 +44,16 @@ async def count(stop, step=1):
 
 
 async def main():
-    print("Spawning countdown immediately, scheduling count for 4 secs from now")
-    async with giambio.TaskManager(loop) as manager:
-        task = await manager.spawn(countdown(4))
-        await manager.schedule(count(8, 2), 4)
-        await task.cancel()
-    for task, ret in manager.values.items():
-        print(f"Function '{task.coroutine.__name__}' at {hex(id(task.coroutine))} returned an object of type '{type(ret).__name__}': {repr(ret)}")
-
+    try:
+        print("Spawning countdown immediately, scheduling count for 4 secs from now")
+        async with giambio.TaskManager(loop) as manager:
+            task = manager.spawn(countdown(4))
+            manager.schedule(count(8, 2), 4)
+            await task.cancel()
+        for task, ret in manager.values.items():
+            print(f"Function '{task.coroutine.__name__}' at {hex(id(task.coroutine))} returned an object of type '{type(ret).__name__}': {repr(ret)}")
+    except:   # TODO: Fix this, see above
+        pass
 
 loop.start(main)
+

giambio/core.py

@@ -10,6 +10,7 @@ from .socket import AsyncSocket, WantRead, WantWrite
 from .abstractions import Task, Result
 from socket import SOL_SOCKET, SO_ERROR
 from .traps import _join, _sleep, _want_read, _want_write, _cancel
+from .util import TaskManager
 
 
 class EventLoop:
@@ -59,10 +60,8 @@ class EventLoop:
                     self.to_run.extend(self.joined.pop(self.running, ()))   # Reschedules the parent task
                 except Exception as has_raised:
                     self.to_run.extend(self.joined.pop(self.running, ()))  # Reschedules the parent task
-                    if self.running.joined:    # Let the join function handle the hassle of propagating the error
-                        self.running.result = Result(None, has_raised)  # Save the exception
-                    else:  # Let the exception propagate (I'm looking at you asyncIO ;))
-                        raise
+                    self.running.result = Result(None, has_raised)  # Save the exception
+                    raise
                 except KeyboardInterrupt:
                     self.running.throw(KeyboardInterrupt)
 
@@ -70,7 +69,7 @@ class EventLoop:
     def start(self, coroutine: types.coroutine, *args, **kwargs):
         """Starts the event loop"""
 
-        self.to_run.append(coroutine(*args, **kwargs))
+        TaskManager(self).spawn(coroutine(*args, **kwargs))
         self.loop()
 
     def want_read(self, sock: socket.socket):
@@ -124,6 +123,7 @@ class EventLoop:
         coroutine returns or, if an exception gets raised, the exception will get propagated inside the
         parent task"""
 
+
         if coro not in self.joined:
             self.joined[coro].append(self.running)
         else:
@@ -137,11 +137,12 @@ class EventLoop:
             self.to_run.append(self.running)    # Reschedule the task that called sleep
 
     def want_cancel(self, task):
-        task.cancelled = True
         self.to_run.extend(self.joined.pop(self.running, ()))
         self.to_run.append(self.running)   # Reschedules the parent task
+#        task.cancelled = True
         task.throw(CancelledError())
 
+
     async def connect_sock(self, sock: socket.socket, addr: tuple):
         try:			# "Borrowed" from curio
             result = sock.connect(addr)

giambio/traps.py

@@ -72,5 +72,6 @@ def _cancel(task):
        be cancelled at any time
     """
 
+    task.cancelled = True
     yield "want_cancel", task
 

giambio/util.py

@@ -18,18 +18,23 @@ class TaskManager:
     async def __aenter__(self):
         return self
 
-    async def __aexit__(self, *args):
-        for task in self.tasks:
-            if task.cancelled:
-                self.values[task] = CancelledError()
-            else:
-                self.values[task] = await task.join(self.silent)
+    async def __aexit__(self, type, value, traceback):
+        if type:
+            # TODO: Handle exceptions here
+            ...
+        else:
+            for task in self.tasks:
+                if not task.cancelled:
+                    self.values[task] = await task.join()
+                else:
+                    self.values[task] = CancelledError()
 
     def spawn(self, coroutine: types.coroutine):
         """Schedules a task for execution, appending it to the call stack"""
 
         task = Task(coroutine, self)
         self.loop.to_run.append(task)
+        self.tasks.append(task)
         return task
 
     def schedule(self, coroutine: types.coroutine, when: int):
@@ -37,5 +42,6 @@ class TaskManager:
 
         self.loop.sequence += 1
         task = Task(coroutine, self)
+        self.tasks.append(task)
         heappush(self.loop.paused, (self.loop.clock() + when, self.loop.sequence, task))
         return task