Signed-off-by: Rosen Penev <rosenp@gmail.com>

shorter
Signed-off-by: Rosen Penev <rosenp@gmail.com>

This reduces duplicates in the music database by hiding the original
song file when it is referenced by a CUE sheet.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1275

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1019

this->OwnsTag() accesses fields that are not yet initialized.

Shorter.
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Enables the "Format" row in "playlistinfo" responses.

https://github.com/MusicPlayerDaemon/MPD/issues/1094

If the constructor moves from an ExportedSong instance which refers to
somebody else's "Tag" instance, the newly constructed instance will
instead refer to its own empty "tag_buffer" field.  This broke
SimpleDatabase::GetSong(), i.e. all songs on the queue restored from
the state file or added using the "addid" command.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1089

After commit 1afa33c3, an old bug was revealed:
SimpleDatabase::GetSong() constructs an ExportedSong instance by
moving the return value of Song::Export(), which causes the
LightSong::tag field to be dangling on the moved-from
ExportedSong::tag_buffer.  This broke tags from CUE sheets.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1070

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1048

Found with cppcoreguidelines-interfaces-global-init
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Shorter.
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Closes https://github.com/MusicPlayerDaemon/MPD/issues/841

The `db->close()` call was a `nullptr` dereference because the `db`
variable had already been moved.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/839

Reduces unstripped size. stripped size is the same.

Also took the time to remove using std::placeholders.
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Eliminates one strlen() call.

Use std::string_view to avoid modifying the string for the temporary
null terminators.

This method gets called a lot during MPD startup, via FindChild() and
directory_load_subdir(), so this is worth optimizing at the expense of
code readability.

This speeds up MPD startup by 10%.