Implement jack2 ilbjackserver.so (control API)

[nedko]

Currently, the functions are stubs:

timur@pop-os:~/jack2$ /usr/bin/jackd -d alsa
jackdmp 1.9.22
Copyright 2001-2005 Paul Davis and others.
Copyright 2004-2016 Grame.
Copyright 2016-2023 Filipe Coelho.
jackdmp comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
[W][01086.573069] default | [ control.c: 67 jackctl_server_create2()] not implemented (nil) (nil) (nil)
[W][01086.573216] default | [ control.c: 154 jackctl_server_get_parameters()] 0x5648831c2910: not implemented
[W][01086.573260] default | [ control.c: 142 jackctl_server_get_drivers_list()] 0x5648831c2910: not implemented
[W][01086.573297] default | [ control.c: 225 jackctl_driver_get_name()] 0x5648831c28f0: not implemented
Unknown driver "alsa"
[W][01086.573352] default | [ control.c: 94 jackctl_server_destroy()] 0x5648831c2910: not implemented

[nedko]

List of control API header improvements over the basic design that suited the initial jackdbus:

• Internal clients, GRAME
• Portability to non-UNIX, Microsoft Windows in particular, sigset_t is replaced with jackctl_sigmask_t (GRAME)
• parameter constraints in control API (nedko)
• Master/Slave driver concept and SwitchMaster, @surfacepatterns (Devin Anderson, no copyright line) and GRAME
• jackctl_server_create() gets two parameters, on_device_acquire and on_device_release, as dbus device reservation was moved to jackdbus on request to keep jackd clean of dbus (nedko)
• jackd "session file" support (Timo Wischer, falktx, no copyright line)
• jackctl_server_create2() with additional on_device_reservation_loop parameter, so that jackd can have device reservation too. ("Fix blocking DBus device reservation, so it plays nice with others"), by falktx, no copyright line

Future non-stub implementation of a libjackserver in PipeWire that is suitable (works without significant regressions against the jack2 version) for LADI/jackdbus will:

• use SPA plugins instead of internal clients (internal client concept is probably mostly reusable)
• Rework clocked driver switching mechanism to one suitable for more than one active master-clocking drivers in the graph (complete rework of the interface Master/Slave/SwitchMaster interface)

[nedko]

With jackdbus:

[W][02010.137229] default | [ control.c: 27 jackctl_setup_signals()] not implemented 0
[W][02010.139548] default | [ control.c: 67 jackctl_server_create2()] not implemented 0x5582ced0ac 0x5582ced21c (nil)
[W][02010.139583] default | [ control.c: 154 jackctl_server_get_parameters()] 0x55afae1d80: not implemented
[W][02010.139599] default | [ control.c: 142 jackctl_server_get_drivers_list()] 0x55afae1d80: not implemented
[W][02010.139610] default | [ control.c: 225 jackctl_driver_get_name()] 0x55afae0ff0: not implemented
[W][02010.139619] default | [ control.c: 241 jackctl_driver_get_parameters()] 0x55afae0ff0: not implemented
[W][02010.139633] default | [ control.c: 165 jackctl_server_get_internals_list()] 0x55afae1d80: not implemented
[E][02010.159988] default | Parameter set failed
[E][02010.160027] default | Ignoring restore attempt of parameter 'engine':'driver':'(null)'
[E][02010.160046] default | Unknown parameter
[E][02010.160053] default | Ignoring restore attempt of parameter 'engine':'realtime-priority':'(null)'
[E][02010.160073] default | Unknown parameter
[E][02010.160082] default | Ignoring restore attempt of parameter 'drivers':'alsa':'device'
[E][02010.160093] default | Unknown parameter
[E][02010.160102] default | Ignoring restore attempt of parameter 'drivers':'alsa':'rate'

[nedko]

[Sat Jun 10 21:30:49] nedko@getson3 ~/git/jackdbus

cat ~/jackserver.pc

prefix=/usr
includedir=${prefix}/include
libdir=${prefix}/lib64
exec_prefix=/usr
jack_implementation=pipewire

Name: jackserver
Description: PipeWire JACK server API
Version: 0.3.71
Libs: -L${libdir} -ljackserver
Cflags: -I${includedir}

[nedko]

Issue #3 tracks the jack client API being not operational for users of libjackserver.so

[nedko]

https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/819