Or technically, two, since the group bridge also does the same loop. We
no longer need special handling for VST2 and VST3 plugins, so we can
simplify things a bit here.
By directly stopping the IO context there was a chance that a task would
get cancelled outright if all stars aligned in the wrong way. Stopping
the IO context could happen between posting the task to the context and
waiting for it. This approach is much safer as we cannot drop any work
this way.
I've never seen this happen, but now this too would support deeply
nested mutual recursion just like we implemented in
`Vst3PlugViewProxyImpl`. Better safe than sorry.
This was a bit of a tricky one because it requires simulating mutual
recursion, but it's needed for REAPER as otherwide calls to
`IPlugFrame::resizeView()` and `IContextMenu::popup()` might cause
REAPER to segfault because its GUI is not thread safe.
This is needed to support Ardour. These extra hops and serialization
steps will probably hurt performance, but outside of some huge hacks (to
connect the components directly anyways) there's not much else we can
do.
This has much fewer moving parts, and it's probably more understandable.
There was also a race condition in the previous implementation, so
there's that.
This requires a super hacky workaround because the UI thread can be
currently blocked by the plugin calling `IPlugFrame::resizeView()` from
the Win32 message loop.
This way every relevant object instance will get its own thread for
handling these calls. The alternative would be creating a full fat
Vst3MessageHandler pair for all object instances, but that would be a
huge waste.
This is quite a huge refactor, but note everything is consistent (and
we're going to need one or two more of these `Vst3*Proxy` objects).
Right now nothing extends `IHostApplication`, but this way it will be
trivial to add support for more host context interfaces.
We're also going to need this for `IEditController`. Separating all of
these classes will also keep everything much more maintainable with all
of these associated structs.
Robbert van der Helm