Is it possible to obtain a `CoroutineContext` from...

# coroutines

[Erik]

Is it possible to obtain a CoroutineContext from Thread.currentThread()? I don't control the current thread instance, but I want to specifically switch to it using e.g. withContext(/*..*/) {}.

[mbonnin]

I guess you could make a CoroutineDispatcher that dispatches to this thread.

[mbonnin]

Mmmm but then if your thread is already started, you can't really submit tasks to it

[mbonnin]

This thread would need to have a task queue or other loop (like an executor for an example)

[Erik]

Maybe I can use fun <T> ThreadLocal<T>.asContextElement(value: T = get()): ThreadContextElement<T> instead

[mbonnin]

I'm not sure. In order to "switch" a coroutine to another thread, you'll have to dispatch

[Erik]

Because I'm trying to work with a thread-confined class on the IO dispatcher. I think that when a coroutine suspends on that dispatcher, when it later resumes there is no guarantee that it will resume on the same thread

[mbonnin]

Yea, <http://Dispatchers.IO|Dispatchers.IO> has multiple threads

[Erik]

I'm also still considering just using a single threaded context for simplicity, there might be other concurrency issues with multiple threads, even if I manage to constrain coroutine access to just 1 thread in the IO dispatcher

[mbonnin]

You'll need to create your dispatcher with only one thread and touch your class only from this thread. Maybe something like:

Executors.newSingleThreadExecutor().asCoroutineDispatcher()

[Erik]

Also, my idea likely breaks some efficiency measures of the IO dispatcher

[Erik]

Thanks for thinking along!