Five faults found while auditing the play/pause and position path for
a desktop report of the pause icon showing over a seek bar that was
not moving. They are one commit because they are one file's worth of
tangled state, and two of them do not compile apart.
The finished callback did not know which chain it came from. It is
dispatched as a goroutine from the beep callback and then queues for
p.mu, so a user pressing Next in the last second of a track had it
wake up holding the lock for a player that had loaded something else
-- and rewind it, stop it, and hand a stale finish to the queue's
auto-advance. updateStreamers now stamps a chainID and the callback
carries the one it was registered with. (#123)
It also emitted PlaybackFinished and PlaybackStateChanged(stopped)
*after* releasing p.mu, alone in this file, so a Play() taking the
lock in that gap emitted `playing` first and the stale `stopped`
landed last -- the button showing play over a track that was audibly
running. Both emits are back under the lock. (#123)
A source that failed mid-track was reported to the queue as a natural
end, so a broken file auto-advanced in silence and was counted as
played. The handler takes the reason now: the player cannot name the
track, because the metadata is the queue's, so the queue emits
PlaybackFailed and skips recording the play. (#123)
p.format was assigned once, in the constructor, to the *speaker's*
rate, and never again -- so it claimed 44.1 kHz for every file. The
replay-after-finish path resamples from it, meaning a finished track
played a second time was resampled from a rate the decoder never
produced: audibly wrong speed and pitch, and the length and position
fallbacks wrong with it. The fixtures are 22050 Hz, which is what lets
a test see this at all. (#124)
p.trackLengthMs was written only when the database had a row and
cleared only by UnloadTrack, so a file with no row inherited the
previous track's duration -- and every position report is scaled by
it, so the bar reported one track's progress on another's scale.
(#125)
Queue.OnPlaybackFinished indexed q.tracks[currentIndex] having checked
only that the queue was non-empty. currentIndex is -1 whenever the
queue has been exhausted, and onQueueExhausted deliberately leaves the
finished track loaded -- so playing it from there and letting it end
panicked, on a goroutine with no caller to recover it. (#126)
The position readers guarded the decoder with the speaker lock, which
the read-ahead goroutine has no reason to hold and never takes -- so
Position() raced readAhead's Stream() on every position emit, once a
second for the whole of playback. srcMu is the lock that excludes that
goroutine, and taking it naively deadlocks, because seekLocked already
holds it and then emits the landing position from inside that region.
seekSourceLocked is that region extracted, so the lock is released
before anything is emitted. Found by the race detector, via the test
added here for the chain guard: the existing suite never loads a file
outside the integration guard, so make test was green over it. (#127)
OnPlaybackFinished picks up //wails:ignore along with its error
parameter: v3's generator segfaults on a bound method taking an error,
and this was never IPC. That removes a binding the frontend could have
called to force an auto-advance.
Closes#123Closes#124Closes#125Closes#126Closes#127
yonlu
2b84bc53e9