gajim3/gajim/common/task_manager.py

109 lines
3.1 KiB
Python

# This file is part of Gajim.
#
# Gajim is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published
# by the Free Software Foundation; version 3 only.
#
# Gajim is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Gajim. If not, see <http://www.gnu.org/licenses/>.
from __future__ import annotations
from typing import List
import functools
import queue
import logging
from gi.repository import GLib
log = logging.getLogger('gajim.c.m.task_manager')
class TaskManager:
def __init__(self):
self._timeout = None
self._queue = queue.PriorityQueue()
def _start_worker(self) -> None:
self._timeout = GLib.timeout_add_seconds(2, self._process_queue)
def _process_queue(self) -> bool:
log.info('%s tasks queued', self._queue.qsize())
requeue = []
while not self._queue.empty():
task = self._queue.get_nowait()
if task.is_obsolete():
log.info('Task obsolete: %r', task)
continue
if not task.preconditions_met():
if task.is_obsolete():
log.info('Task obsolete: %r', task)
else:
requeue.append(task)
continue
log.info('Execute task %r', task)
task.execute()
self._requeue_tasks(requeue)
return True
if self._requeue_tasks(requeue):
# Queue is empty, but there are tasks to requeue
# don't stop worker
return True
# Queue is empty, stop worker
self._timeout = None
return False
def _requeue_tasks(self, tasks: List[Task]) -> bool:
if not tasks:
return False
for task in tasks:
log.info('Requeue task (preconditions not met): %r', task)
self._queue.put_nowait(task)
return True
def add_task(self, task: Task) -> None:
log.info('Adding task: %r', task)
self._queue.put_nowait(task)
if self._timeout is None:
self._start_worker()
@functools.total_ordering
class Task:
def __init__(self, priority: int = 0):
self.priority = priority
self._obsolete = False
def is_obsolete(self) -> bool:
return self._obsolete
def set_obsolete(self) -> None:
self._obsolete = True
def __lt__(self, other: object) -> bool:
if not isinstance(other, Task):
raise NotImplementedError
return self.priority < other.priority
def __eq__(self, other: object) -> bool:
if not isinstance(other, Task):
raise NotImplementedError
return other.priority == self.priority
def execute(self) -> None:
raise NotImplementedError
def preconditions_met(self) -> bool:
raise NotImplementedError