In this state, we can't make any progress.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1084

Drain only if it was requested explicitly.

It is useless, because we're always checking pa_stream_is_corked().

[[maybe_unused]] (introduced in C++17) is standard C++.

https://clang.llvm.org/docs/AttributeReference.html#maybe-unused-unused
says that this is equivalent to the GNU unused attribute.
Signed-off-by: Rosen Penev <rosenp@gmail.com>

The former is deprecated with C++14. The standard says both are the same:

The contents and meaning of the header<cstddef>are the same as the C
standard library header<stddef.h>,except that it does not declare the type
wchar_t, that it also declares the type byte and its associated
operations (21.2.5), and as noted in 21.2.3 and 21.2.4.
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>

Introduced in C++17. It replaces gcc's warn_unused_result.

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

Found with modernize-redundant-void-arg
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Closes https://github.com/MusicPlayerDaemon/MPD/issues/708

This is useful in multiple mpd instances scenario, or multiple pulse outputs defined on the same mpd instance.
It is actually a more flexible way to route flows than the "sink" parameter, letting the PulseAudio routing do its job, but with the ability to isolate routing for each output.

If not specified, the role remains like it was before this commit, ie "music"

Unlike pa_channel_map_init_auto(), pa_channel_map_init_extend() does
not fail if there is no valid mapping for the given channel count, but
instead maps additional "AUX" channels.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/493

Since we switched from autotools to Meson in commit
94592c14, 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.

The PulseOutput needs to be "enabled" before WaitConnection() may be
called.

Closes #207

Coverity discovered that the Pulse plugin could throw exceptions from
Pause(), but that method was marked "noexcept" because its caller was
not designed to catch exceptions.  So instead of avoiding exceptions
(by catching and logging them in each and every implementation), let's
allow them, and do the catch/log game in the MPD core.

Yet another C-style vtable replaced with C++.

Hide struct FilteredAudioOutput from the plugins, preparing for hiding
MPD's core internals.

Prepare to add an abstract class AudioOutput, to be implemented by
plugins, to get rid of the C-style vtable.

Don't access AudioOutput::pause.

Fixes build failure on OS X, closes #44.  With the other plugins,
that's not critical, because those use the AudioOutputWrapper, which
hides this problem.

This eliminates some overhead, because the compiler doesn't need to
consider these functions throwing.

Eliminate dependency on io_thread_get().

Make all the locks exception-safe.

Currently the switch statement is invalidated by ss.format being overwritten
with the default value of PA_SIMPLE_S16NE which results in white noise during
playback as my server is expected S16LE (S16NE).
Signed-off-by: Earnestly <zibeon@gmail.com>

This is based on a patch from Ian Scott in 2014. It was never committed,
so I figured I'd fix the outstanding issue and resubmit it.

https://www.mail-archive.com/mpd-devel%40musicpd.org/msg00139.html