Fixes hide_playlist_targets not working after server restart
Currently, `hide_playlists_targets` works by skipping songs with
`in_playlist` value set to true in
[`Directory::Walk`](a57bcd0238/src/db/plugins/simple/Directory.cxx (L237)). But
`in_playlist` is not stored and only updated in
[`UpdateWalk::PurgeDanglingFromPlaylists`](a57bcd0238/src/db/update/Playlist.cxx (L139)),
which will only be executed while updating DB.
This causes the problem that playlist target songs are correctly
hidden after database update, but will remain visible after mpd server
restarted. This pr solves the problem by storing `in_playlist` value
of songs into the `SimpleDatabase` file.
This commit adds a PlaylistPlugin attribute "as_folder" which for now
is only enabled in the "CUE" playlist plugin (which handles separate
"*.cue" files). If a playlist with this flag set is being scanned
during database update, it will be parsed and its contents will be
added to the database. This allows clients to inspect them like
directories and its contents will be searchable.
Closes https://github.com/MusicPlayerDaemon/MPD/issues/39
Since we switched from autotools to Meson in commit
94592c1406, we don't need to include
`config.h` early to properly enable large file support. Meson passes
the required macros on the compiler command line instead of defining
them in `config.h`.
This means we can include `config.h` at any time, whenever we want to
check its macros, and there are no ordering constraints.
If a directory is a mount point, omit the "directory: " as well.
This bug is years old, but has become more visible now that mount
points are persistent in the state file.
A SimpleDatabase instance can now "mount" other Database instances at
certain locations. This is used to use a new SimpleDatabase instance
for each storage mount (issued with the "mount" protocol command).
Each such instance has its own database file, stored in the directory
that is specified with the "cache_directory" option.
