Can Controller be Send and Sync?

[adeschamps]

I think we can implement Send and Sync for Controller, but I'd like someone else to weigh in before I submit a PR. Send and Sync are not implemented automatically because Controller contains raw pointers.

I believe they are safe to implement because nothing in the Controller API gives access to its internal ws_2811_t C struct. Since it is the only thing that can access it, there is no possibility of pointer aliasing.

My use case is that I would like to initialize Controller and then create a thread that accepts messages via a channel and changes lights. Without implementing Send, I would have to initialize Controller inside this thread, which means I can't handle initialization errors before spinning up the thread.

[JMurph2015]

Sorry for the late reply, but college finals just finished up so I'm finally able to spend some time programming fun things.

Basically, I'm not sure it can implement either safely due to the wrapping of the ws2811_t structs from the core library. It's not clear that either are valid assumptions about the memory managed by rpi_ws281x, and unfortunately since this library directly wraps an object managed by rpi_ws281x, we can't be sure without inspecting the C library, which will be some non-trivial amount of effort.