Lewis Baker lewissbaker

P1055 and P0443 - a compromise

Summary

The goal here is to provide a minimal set of changes to P0443 that allows us to aim for a clean, lazy-by-default API, that does not drastically change the expectations of the P0443 authors.

I am making a few assumptions in writing this:

I am not worrying about bikeshedding names. Where appropriate I will use names from P0443 even if they don't really make sense any more as names. We can change them.
I believe we may wish to tweak the particular parameters to the bulk execute operation. We will likely also want other types of task such as a value + error task as I described in P1054. I do not worry about that here.
I do not expect changes to the properties mechanism except in so much as the types they return may differ slightly.

	ssize_t getAsyncStackTraceSafe(uintptr_t* addresses, size_t maxAddresses) {
	size_t numFrames = 0;

	// Start by walking the normal stack until we get to the frame right before
	// the frame that holds the async root.
	StackFrame* normalStackFrame = (StackFrame*)FOLLY_ASYNC_STACK_FRAME_POINTER();
	StackFrame* normalStackFrameStop = nullptr;

	const auto* asyncStackRoot = tryGetCurrentAsyncStackRoot();
	AsyncStackFrame* asyncStackFrame = nullptr;