This should be a last stop-gap measure in case sourcekitd or clangd get stuck, don’t respond to any requests anymore and don’t honor cancellation either. In that case we can restore SourceKit-LSP behavior by killing them and using the crash recovery logic to restore functionality.
rdar://149492159
There is only one real class that implements the `SourceKitD` protocol, so there really isn’t any need for the protocol + class split at all. Unify them to make code simpler to reason about.
Otherwise, the cancellation could get handled before the request actually gets sent to sourcekitd, which is not what we want to test here. There appears to be a second underlying issue that causes unexpected results when we cancel the fast completion request after sending the slow completion request. I’ll look at that in a follow-up PR.
This adds a sourcekitd plugin that drives the code completion requests. It also includes a `CompletionScoring` module that’s used to rank code completion results based on their contextual match, allowing us to show more relevant code completion results at the top.
