95 lines
3.0 KiB
Python
95 lines
3.0 KiB
Python
# Copyright 2022 (c) Anna Schumaker
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"""Idle queues to assid with large database operations."""
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import typing
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from gi.repository import GObject
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from gi.repository import GLib
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class Queue(GObject.GObject):
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"""A base class Idle Queue."""
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total = GObject.Property(type=int)
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progress = GObject.Property(type=float)
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running = GObject.Property(type=bool, default=False)
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enabled = GObject.Property(type=bool, default=True)
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def __init__(self, **kwargs):
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"""Initialize an Idle Queue."""
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super().__init__(**kwargs)
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self._tasks = []
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self._idle_id = None
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def __getitem__(self, n: int) -> tuple:
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"""Get the n-th task in the queue."""
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return self._tasks[n] if n < len(self._tasks) else None
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def __run_next_task(self) -> None:
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task = self._tasks[0]
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if task[0](*task[1:]):
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self._tasks.pop(0)
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def __start(self) -> None:
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if not self.running:
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self.running = True
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self._idle_id = GLib.idle_add(self.run_task)
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self.__update_counters()
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def __update_counters(self) -> bool:
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if (pending := len(self._tasks)) == 0:
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self.cancel()
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return GLib.SOURCE_REMOVE
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self.progress = 1 - (pending / self.total)
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return GLib.SOURCE_CONTINUE
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def cancel(self) -> None:
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"""Cancel all pending tasks."""
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if self._idle_id is not None:
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GLib.source_remove(self._idle_id)
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self._tasks.clear()
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self.progress = 0.0
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self.total = 0
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self.running = False
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self._idle_id = None
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def cancel_task(self, func: typing.Callable) -> None:
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"""Remove all instances of a specific task from the Idle Queue."""
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self._tasks = [t for t in self._tasks if t[0] != func]
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self.__update_counters()
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def complete(self) -> None:
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"""Complete all pending tasks."""
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if self.running:
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while len(self._tasks) > 0:
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self.__run_next_task()
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self.cancel()
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def push(self, func: typing.Callable, *args,
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now: bool = False, first: bool = False) -> bool | None:
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"""Add a task to the Idle Queue."""
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if not self.enabled or now:
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return func(*args)
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pos = 0 if first else len(self._tasks)
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self._tasks.insert(pos, (func, *args))
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self.total += 1
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self.__start()
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def push_many(self, func: typing.Callable, args: list[tuple[any]],
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now: bool = False) -> None:
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"""Add several tasks to the Idle Queue."""
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if not self.enabled or now:
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for arg in args:
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func(*arg)
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else:
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self._tasks.extend([(func, *arg) for arg in args])
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self.total += len(args)
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self.__start()
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def run_task(self) -> bool:
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"""Manually run the next task."""
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if len(self._tasks) > 0:
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self.__run_next_task()
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return self.__update_counters()
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return GLib.SOURCE_REMOVE
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