* Call `Sink::clear`/`Sink::skip_one` on an empty `Sink` will permanently skip any `Source` append to it
* Call `Sink::clear` on an non-empty `Sink` can't reset it's length().
* Clear and Skip functionality added
Added a clear() and skip_one() method to the Sink impl
* Use one lock for clear
Return the length in the queue clear function so that we don't have to get a lock twice.
* Rework skip to mark all sources as skippable
---------
Co-authored-by: Nathan Abel <abel8706@kettering.edu>
Co-authored-by: Ivar Kamsvåg <ivaka037@student.liu.se>
Co-authored-by: est31 <est31@users.noreply.github.com>
Addressing issues #462 and #315 and #171
Given how the sink's queue is drained on stop I made some modifications in sink.append(). I added a check to ensure the sink was flushed completely (not sure this is necessary? I think it is, to avoid race conditions) and to restart the sink on append (when stopped.)
I added a test demonstrating correctness, as well as performing some trials on my own.
This example plays a C Major 6th chord by adding four sources, sine waves frequencies of C, E, G, and A, to a `DynamicMixerController`, and appends its respective `DynamicMixer` to a sink.
As I understand it, this is the issue:
* Previously, when a queue has `keep_alive_if_empty` set to true, and it becomes empty, then it will push a silence lasting 10ms onto the queue.
* This is an issue because `current_frame_len` would have returned the worst case, `512`, and the silence lasts less than that.
* This means that unless the source is added immediately to the queue, and so a silence is never played, then the first actual source could start playing at a frame that is not aligned to its channels, or play at the wrong sample rate.
* This is only determined by when the source is added to the queue after its initialization. This explains why the issue was inconsistent, as it relied on the speed of execution of code which is basically random.
Solution
* Change the functionality of `Zero` to add a method to create a silence with a certain number of frames.
* Replace the 10ms silence with a silence the length of `THRESHOLD`
* Change queue's `current_frame_len` to return `THRESHOLD` if a silence will be played next.
