261 lines
8.4 KiB
Python
261 lines
8.4 KiB
Python
# ##### BEGIN GPL LICENSE BLOCK #####
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#
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# This program is free software; you can redistribute it and/or
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# modify it under the terms of the GNU General Public License
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# as published by the Free Software Foundation; either version 2
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# of the License, or (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software Foundation,
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# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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#
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# ##### END GPL LICENSE BLOCK #####
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"""Manages the asyncio loop."""
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import asyncio
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import traceback
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import concurrent.futures
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import logging
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import gc
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import bpy
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log = logging.getLogger(__name__)
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# Keeps track of whether a loop-kicking operator is already running.
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_loop_kicking_operator_running = False
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def setup_asyncio_executor():
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"""Sets up AsyncIO to run on a single thread.
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This ensures that only one Pillar HTTP call is performed at the same time. Other
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calls that could be performed in parallel are queued, and thus we can
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reliably cancel them.
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"""
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executor = concurrent.futures.ThreadPoolExecutor()
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loop = asyncio.get_event_loop()
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loop.set_default_executor(executor)
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# loop.set_debug(True)
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def kick_async_loop(*args) -> bool:
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"""Performs a single iteration of the asyncio event loop.
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:return: whether the asyncio loop should stop after this kick.
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"""
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loop = asyncio.get_event_loop()
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# Even when we want to stop, we always need to do one more
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# 'kick' to handle task-done callbacks.
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stop_after_this_kick = False
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if loop.is_closed():
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log.warning('loop closed, stopping immediately.')
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return True
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all_tasks = asyncio.Task.all_tasks()
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if not len(all_tasks):
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log.debug('no more scheduled tasks, stopping after this kick.')
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stop_after_this_kick = True
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elif all(task.done() for task in all_tasks):
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log.debug('all %i tasks are done, fetching results and stopping after this kick.',
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len(all_tasks))
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stop_after_this_kick = True
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# Clean up circular references between tasks.
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gc.collect()
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for task_idx, task in enumerate(all_tasks):
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if not task.done():
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continue
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# noinspection PyBroadException
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try:
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res = task.result()
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log.debug(' task #%i: result=%r', task_idx, res)
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except asyncio.CancelledError:
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# No problem, we want to stop anyway.
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log.debug(' task #%i: cancelled', task_idx)
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except Exception:
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print('{}: resulted in exception'.format(task))
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traceback.print_exc()
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# for ref in gc.get_referrers(task):
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# log.debug(' - referred by %s', ref)
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loop.stop()
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loop.run_forever()
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return stop_after_this_kick
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def ensure_async_loop():
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log.debug('Starting asyncio loop')
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result = bpy.ops.asyncio.loop()
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log.debug('Result of starting modal operator is %r', result)
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def erase_async_loop():
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global _loop_kicking_operator_running
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log.debug('Erasing async loop')
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loop = asyncio.get_event_loop()
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loop.stop()
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class AsyncLoopModalOperator(bpy.types.Operator):
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bl_idname = 'asyncio.loop'
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bl_label = 'Runs the asyncio main loop'
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timer = None
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log = logging.getLogger(__name__ + '.AsyncLoopModalOperator')
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def __del__(self):
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global _loop_kicking_operator_running
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# This can be required when the operator is running while Blender
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# (re)loads a file. The operator then doesn't get the chance to
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# finish the async tasks, hence stop_after_this_kick is never True.
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_loop_kicking_operator_running = False
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def execute(self, context):
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return self.invoke(context, None)
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def invoke(self, context, event):
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global _loop_kicking_operator_running
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if _loop_kicking_operator_running:
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self.log.debug('Another loop-kicking operator is already running.')
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return {'PASS_THROUGH'}
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context.window_manager.modal_handler_add(self)
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_loop_kicking_operator_running = True
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wm = context.window_manager
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self.timer = wm.event_timer_add(0.00001, context.window)
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return {'RUNNING_MODAL'}
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def modal(self, context, event):
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global _loop_kicking_operator_running
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# If _loop_kicking_operator_running is set to False, someone called
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# erase_async_loop(). This is a signal that we really should stop
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# running.
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if not _loop_kicking_operator_running:
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return {'FINISHED'}
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if event.type != 'TIMER':
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return {'PASS_THROUGH'}
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# self.log.debug('KICKING LOOP')
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stop_after_this_kick = kick_async_loop()
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if stop_after_this_kick:
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context.window_manager.event_timer_remove(self.timer)
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_loop_kicking_operator_running = False
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self.log.debug('Stopped asyncio loop kicking')
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return {'FINISHED'}
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return {'RUNNING_MODAL'}
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# noinspection PyAttributeOutsideInit
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class AsyncModalOperatorMixin:
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async_task = None # asyncio task for fetching thumbnails
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signalling_future = None # asyncio future for signalling that we want to cancel everything.
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log = logging.getLogger('%s.AsyncModalOperatorMixin' % __name__)
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_state = 'INITIALIZING'
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def invoke(self, context, event):
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context.window_manager.modal_handler_add(self)
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self.timer = context.window_manager.event_timer_add(1 / 15, context.window)
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return {'RUNNING_MODAL'}
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def execute(self, context):
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return self.invoke(context, None)
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def modal(self, context, event):
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task = self.async_task
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if self._state != 'EXCEPTION' and task and task.done() and not task.cancelled():
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ex = task.exception()
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if ex is not None:
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self._state = 'EXCEPTION'
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self.log.error('Exception while running task: %s', ex)
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return {'RUNNING_MODAL'}
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if self._state == 'QUIT':
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self._finish(context)
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return {'FINISHED'}
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return {'PASS_THROUGH'}
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def _finish(self, context):
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self._stop_async_task()
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context.window_manager.event_timer_remove(self.timer)
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def _new_async_task(self, async_task: asyncio.coroutine, future: asyncio.Future = None):
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"""Stops the currently running async task, and starts another one."""
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self.log.debug('Setting up a new task %r, so any existing task must be stopped', async_task)
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self._stop_async_task()
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# Download the previews asynchronously.
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self.signalling_future = future or asyncio.Future()
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self.async_task = asyncio.ensure_future(async_task)
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self.log.debug('Created new task %r', self.async_task)
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# Start the async manager so everything happens.
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ensure_async_loop()
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def _stop_async_task(self):
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self.log.debug('Stopping async task')
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if self.async_task is None:
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self.log.debug('No async task, trivially stopped')
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return
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# Signal that we want to stop.
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self.async_task.cancel()
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if not self.signalling_future.done():
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self.log.info("Signalling that we want to cancel anything that's running.")
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self.signalling_future.cancel()
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# Wait until the asynchronous task is done.
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if not self.async_task.done():
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self.log.info("blocking until async task is done.")
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loop = asyncio.get_event_loop()
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try:
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loop.run_until_complete(self.async_task)
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except asyncio.CancelledError:
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self.log.info('Asynchronous task was cancelled')
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return
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# noinspection PyBroadException
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try:
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self.async_task.result() # This re-raises any exception of the task.
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except asyncio.CancelledError:
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self.log.info('Asynchronous task was cancelled')
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except Exception:
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self.log.exception("Exception from asynchronous task")
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def register():
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bpy.utils.register_class(AsyncLoopModalOperator)
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def unregister():
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bpy.utils.unregister_class(AsyncLoopModalOperator)
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