[Jack-Devel] JACK iOS (RIP) (was: JACK on mobile)

On Thursday 17 October 2013 10:54:11 Dan MacDonald wrote:
> Christian:
> 
> JACK iOS is dead already? Why? There is no mention or explanation of its
> passing on its homepage that I can see.

Yes, you can consider JACK iOS dead, because starting with iOS 7.0 Apple 
decided to block all IPC mechanisms between third party apps. So you can't 
establish shared memory, native Mach port connections or any other way to 
communicate with foreign apps anymore. That's the reason why the JACK app 
won't launch on iOS 7 anymore. It crashes immediately right after the point 
when it tries to establish shared memory. You can now (iOS7) only use specific 
IPC APIs for processes that are part of apps signed with the same team profile 
/ signature, that is IPC is now limited explicitly to your own and only to 
your own apps.

Stéphane filed a bug report (#14988888) at Apple's BTS and I also asked for 
some statement from Apple's side i.e. on their Developer forum and Apple 
engineers directly, but all requests concerning this particular issue were 
ignored by them. Many other app developers have the problem of course, and 
they also filed reports etc., but nobody got any reply. So it seems to be 
consciously ignored.

The reason why we haven't updated the website yet, was simply to wait a bit 
for some potential "official" response still to come from Apple, but at this 
point I don't actually expect this to happen anymore.

I was actually a bit shocked how aggressively Apple enforced this new policy 
(disallowing custom IPC that is). This is a very drastic change in the OS, 
which was never officially announced, nor was it as of to date mentioned in 
any developer resource like API docs, header files, API diffs or anything 
else. And I would at least expect a deprecation / grace period for such a huge 
new OS restriction.

At this year's WWDC an Apple engineer mentioned in a personal conversation 
(unofficially) that native Mach ports might get blocked in iOS 7, however I 
was optimistic that this would not be applied to all IPCs facilities entirely. 
But I was false.

You might ask how Audiobus managed to solve it. To my knowledge they actually 
dropped their previously used audio server backend (which was poor anyway) and 
instead turned the Audiobus app simply to be an "Inter-App Audio" (IAA) host. 
The latter is a new (quite limited) system introduced by Apple with iOS 7 for 
connecting audio apps with each other. Unfortunately for JACK we cannot do as 
the Audiobus authors did. Because JACK is far more powerful than IAA and 
JACK's concept would not fit into the IAA framework at all. Of course we could 
recycle the JACK iOS GUI for a new app on top of Apple's IAA system, but as 
said this would then just be yet another IAA host app, not JACK anymore, and 
accordingly would have the exact same limitations as any other IAA host app.

CU
Christian

1382014024.20582_0.ltw:2, <201310171452.33575.schoenebeck at crudebyte dot com>