On the way to using interrupts

[tmh-alex]

@washed I started on the interrupts and ofc I ran into problems. Maybe you can point me to how to move on...?

Multiple problems here:

• Code does nothing if I don't spawn a thread running a loop just to (so I think) extend the lifetime of 'pin' (otherwise the interrupt handler, which is attached to pin, is cleared, see this). This is stupid given that the interrupt handler will spawn its own thread upon a trigger event.
• The callback function needs to have a reference to either Self or 'pin' and 'sender' in order to do its work, and I don't know how to properly pass those without violating every single borrow and mutability rule.

I could just adapt the existing implementation to use poll_interrupt, using set_async_interrupt, however, is more educational :)

[washed]

@tmh-alex i pushed a possible way out of some of the issues to this branch. I couldn't test it because i can't access the hardware at the moment. But basically:

• keeps the pin in the Button struct, which should extend it's lifetime as long as button is alive
• instantiate a debouncer, make it send a message when a debounced event happened through our channel
• put the raw interrupt events into the debouncer by moving it into the interrupt callback closure
• we could also send messages through channels directly from our interrupt callback by moving the sender into the callback closure, same as with the debouncer

not tested!

[tmh-alex]

@washed Thanks for the inputs! I'm afraid it doesn't work though. Moving pin into the struct was one of my attempts as well. At least I now learned more about move.

[tmh-alex]

@washed If you don't mind, may I ask you to open a new branch on top of this one for your changes just like you did on the volume buttons PR? I would like to push through with my own attempts here while following your hints and suggestions (like the debounce crate, nice one). Thanks :slightly_smiling_face:

[washed]

Okay, you can try putting the pin into an Rc or Arc (make sure to clone it once to increment the reference counter), if the issue is the pin getting dropped.

Sorry for pushing on your branch, I was in a hurry. Will fix later.