H-13: no Play, no Shuffle, no Add to queue on the album header. The
reason it is not just three buttons is that explore-album-details is a
catalog page — there is no library-side album detail page at all — so
the album shown may be wholly the user's, partly theirs, or not theirs.
A Play button that plays 7 of a 40-track release under a label saying
'Play' is the page lying about what is owned, so the button says which:
'Play' when all of it is owned, 'Play 7 of 12' when some is, and no
play button at all when none is.
albumLibraryStatus() stays as it was — four claims of decreasing
confidence OR'd into one tick, the weakest firing when a single
recording matches. That is a fine answer to 'is any of this mine' and a
useless basis for a button, so ownership() counts the displayed
tracklist instead.
GetFilePathsByRecordingMBIDs is the catalog-side sibling of
GetFilePathsByAlbums: one query, paths only, grouped so the caller
keeps the tracklist's order. It is keyed on recording MBID because that
is how the backend decides a track is inLibrary, and because
MBTrack.LocalID is declared and never written by anything. The local
album id is preferred where there is one — a library-only album has no
MBIDs at all, and keying on them alone queued nothing.
The ticks also get the legend H-13 asks for. They were never unlabelled
— the indicator has carried a title and aria-label all along — but a
sighted user got a column of green circles and no key.
"Play this artist" awaited `GetAlbumTracks` inside a for loop — 13
sequential round trips for a 12-album artist — and every one of the
four sites doing that asked for whole track rows to read `FilePath`
off them. Five genres cost 6 MB across the IPC.
`GetFilePathsByAlbums(ids, libraryID)` and `GetFilePathsByGenres(names,
libraryID)` answer once and carry only the paths. Measured at 50 000
tracks: an artist 13 calls / 74.2 kB -> 2 / 19.2 kB, twenty albums
20 / 117.5 kB / 7.8 ms -> 1 / 26.0 kB / 1.7 ms, five genres
5 / 6 014 kB / 213 ms -> 1 / 1 291 kB / 32.6 ms, with the returned path
lists identical.
They return the paths grouped by album id or genre name rather than
flattened, because the caller owns the order — an album list is sorted
by name, not by id, and a flattened result would silently reorder a
queue — and because the album drag cache stores them per album. A
libraryID of 0 means "every library", matching an unset filter.
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