workers: basic event loop (#3828)

* establish basic event loop for workers
* make "self.close()" inside worker
* remove "runWorkerMessageLoop() - instead manually call global function 
  in Rust when message arrives. This is done in preparation for structured clone
* refactor "WorkerChannel" and use distinct structs for internal 
  and external channels;  "WorkerChannelsInternal" and "WorkerHandle"
* move "State.worker_channels_internal" to "Worker.internal_channels"
* add "WorkerEvent" enum for child->host communication; 
  currently "Message(Buf)" and  "Error(ErrBox)" variants are supported
* add tests for nested workers
* add tests for worker throwing error on startup

1 files changed, 8 insertions, 19 deletions

diff --git a/cli/tokio_util.rs b/cli/tokio_util.rs
index e5878cdf7..0e1257da7 100644
--- a/cli/tokio_util.rs
+++ b/cli/tokio_util.rs
@@ -1,30 +1,19 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 
-// TODO(ry) rename to run_local ?
-pub fn run_basic<F, R>(future: F) -> R
-where
-  F: std::future::Future<Output = R> + 'static,
-{
-  let mut rt = tokio::runtime::Builder::new()
+pub fn create_basic_runtime() -> tokio::runtime::Runtime {
+  tokio::runtime::Builder::new()
     .basic_scheduler()
     .enable_io()
     .enable_time()
     .build()
-    .unwrap();
-  rt.block_on(future)
+    .unwrap()
 }
 
-// TODO(ry) maybe replace with tokio::task::spawn_blocking
-#[cfg(test)]
-pub fn spawn_thread<F, R>(f: F) -> impl std::future::Future<Output = R>
+// TODO(ry) rename to run_local ?
+pub fn run_basic<F, R>(future: F) -> R
 where
-  F: 'static + Send + FnOnce() -> R,
-  R: 'static + Send,
+  F: std::future::Future<Output = R> + 'static,
 {
-  let (sender, receiver) = tokio::sync::oneshot::channel::<R>();
-  std::thread::spawn(move || {
-    let result = f();
-    sender.send(result)
-  });
-  async { receiver.await.unwrap() }
+  let mut rt = create_basic_runtime();
+  rt.block_on(future)
 }