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

This reverts commit 9200fa6d.  It was
wrong because it works only if the target song has already been
scanned.

make_pair is an old C++98 function that can be replaced by modern
shorter constructs.
Signed-off-by: Rosen Penev <rosenp@gmail.com>

These should be equivalent anyway.
Signed-off-by: Rosen Penev <rosenp@gmail.com>

loop is wrong anyway. It's missing a break;
Signed-off-by: Rosen Penev <rosenp@gmail.com>

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

Prepending "../" to absolute URIs would break them.

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

Found with cppcoreguidelines-special-member-functions
Signed-off-by: Rosen Penev <rosenp@gmail.com>

When updating everything, this did work, but if updating only a
subdirectory, the ".mpdignore" in the parents were not used.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1172

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1130

Remove lots of #ifdefs.

Allows using ranges, always.  This is required to fix
https://github.com/MusicPlayerDaemon/MPD/issues/1130 without adding
more runtime conditionals.

libnpupnp is a C++ modification of libupnp.
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Add support for the following tags when using the proxy database plugin:
WORK
CONDUCTOR
LABEL
GROUPING
MUSICBRAINZ_WORKID
COMPOSERSORT
ENSEMBLE
MOVEMENT
MOVEMENTNUMBER
LOCATION

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

Preparing for a variant of TimerEvent with coarse 1-second
granularity, but cheaper (with a timer wheel).

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