113 lines
3.1 KiB
Python
113 lines
3.1 KiB
Python
"""
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aiosched: Yet another Python async scheduler
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Copyright (C) 2022 nocturn9x
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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https:www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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"""
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from aiosched.task import Task
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from aiosched.internals.syscalls import spawn, wait, cancel
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from typing import Any, Coroutine, Callable
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class TaskContext(Task):
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"""
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An asynchronous task context that automatically waits
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for all tasks spawned within it. A TaskContext object
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behaves like a task and is handled as a single unit
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inside the event loop
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"""
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def __init__(self) -> None:
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"""
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Object constructor
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"""
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# All the tasks that belong to this context. This
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# includes any inner contexts contained within this
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# one
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self.tasks: list[Task | "TaskContext"] = []
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# Whether we have been cancelled or not
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self.cancelled: bool = False
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super().__init__(f"TaskContext object at {hex(id(self))}", None)
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async def spawn(
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self, func: Callable[..., Coroutine[Any, Any, Any]], *args, **kwargs
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) -> Task:
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"""
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Spawns a child task
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"""
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task = await spawn(func, *args, **kwargs)
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self.tasks.append(task)
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return task
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async def __aenter__(self):
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"""
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Implements the asynchronous context manager interface
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"""
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return self
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async def __aexit__(self, exc_type: Exception, exc: Exception, tb):
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"""
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Implements the asynchronous context manager interface, waiting
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for all the tasks spawned inside the context
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"""
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for task in self.tasks:
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# This forces the interpreter to stop at the
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# end of the block and wait for all
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# children to exit
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try:
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await wait(task)
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self.tasks.remove(task)
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except BaseException:
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self.tasks.remove(task)
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await self.cancel()
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raise
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async def cancel(self):
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"""
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Cancels the entire context, iterating over all
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of its tasks and cancelling them
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"""
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for task in self.tasks:
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await cancel(task)
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self.cancelled = True
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self.tasks = []
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def done(self) -> bool:
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"""
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Returns True if all the tasks inside the
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context have exited, False otherwise
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"""
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return all([task.done() for task in self.tasks])
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def __del__(self):
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"""
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Context destructor
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"""
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for task in self.tasks:
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task.__del__()
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def __repr__(self):
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"""
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Implements repr(self)
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"""
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return f"TaskContext({self.tasks})"
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