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

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

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

For querying tags, the real song URI should be used, because if the
(display) URI is different, requesting it will not produce a usable
response.  This is a theoretical problem because none of the existing
playlist plugins sets the real_uri.

This requires changing the URI comparison in playlist::TagModified().

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1154

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

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

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

Found with readability-use-anyofallof
Signed-off-by: Rosen Penev <rosenp@gmail.com>

std::all_of becomes constexpr in C++20. I'm not sure it results in better
performance.

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

The former is deprecated by C++14. The standard says they are the same:

The header defines all types and macros the same as the C standard library
header<stdint.h>.
Signed-off-by: Rosen Penev <rosenp@gmail.com>

The former was deprecated with C++14.

According to the C++11 and C++17 standards, both files are identical.
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Found with modernize-use-equals-default
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Prepare for allowing ISO8601 time stamps without delimiters, such as
20191216, and prevent them from being interpreted as numeric UNIX time
stamps.

The old implementation didn't make a lot of sense; the "!=" operator
was not actually the opposite of "==".

Closes https://github.com/MusicPlayerDaemon/MPD/issues/505

The "NN" suffix used to mean "no negation", but that's not how it's
implemented today.