task-internals.rst

How the dvbcss.task module works internally

Introduction

The :mod:`dvbcss.task` module internally implements a task scheduler based around a single daemon thread with an internal priority queue.

Sleep and callback methods cause a task objet to be queued. The scheduler picks up the queued task and adds it to the priority queue and binds to the Clock so that it is notified of adjustments to the clock. When a task is added to the queue, the clock is queried to calculate the true time at which the tick count is expected to be reached by calling :func:`dvbcss.clock.ClockBase.calcWhen`

If a clock is adjusted the affected tasks are marked as deprecated (but remain in the priority queue) and new tasks are scheduled with a recalculated time.

Objects

.. autodata:: dvbcss.task.scheduler

   Running instance of the :class:`dvbcss.task._Scheduler`

Classes

.. autoclass:: dvbcss.task._Scheduler
   :members:

.. autoclass:: dvbcss.task._Task
   :members: