refactor: split cli::Worker (#3735)

* cli::Worker is base struct to create specialized workers
* add MainWorker
* add CompilerWorker
* refactor WebWorker to use Worker

cli/compilers/compiler_worker.rs

@@ -0,0 +1,78 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+use crate::ops;
+use crate::state::ThreadSafeState;
+use crate::worker::Worker;
+use crate::worker::WorkerChannels;
+use deno_core;
+use deno_core::ErrBox;
+use deno_core::StartupData;
+use futures::future::FutureExt;
+use std::future::Future;
+use std::ops::Deref;
+use std::ops::DerefMut;
+use std::pin::Pin;
+use std::task::Context;
+use std::task::Poll;
+
+/// This worker is used to host TypeScript and WASM compilers.
+///
+/// It provides minimal set of ops that are necessary to facilitate
+/// compilation.
+///
+/// NOTE: This worker is considered priveleged, because it may
+/// access file system without permission check.
+///
+/// At the moment this worker is meant to be single-use - after
+/// performing single compilation/bundling it should be destroyed.
+///
+/// TODO(bartlomieju): add support to reuse the worker - or in other
+/// words support stateful TS compiler
+#[derive(Clone)]
+pub struct CompilerWorker(Worker);
+
+impl CompilerWorker {
+  pub fn new(
+    name: String,
+    startup_data: StartupData,
+    state: ThreadSafeState,
+    external_channels: WorkerChannels,
+  ) -> Self {
+    let state_ = state.clone();
+    let worker = Worker::new(name, startup_data, state_, external_channels);
+    {
+      let mut isolate = worker.isolate.try_lock().unwrap();
+      ops::compiler::init(&mut isolate, &state);
+      ops::web_worker::init(&mut isolate, &state);
+      // TODO(bartlomieju): CompilerWorker should not
+      // depend on those ops
+      ops::os::init(&mut isolate, &state);
+      ops::files::init(&mut isolate, &state);
+      ops::fs::init(&mut isolate, &state);
+      ops::io::init(&mut isolate, &state);
+    }
+
+    Self(worker)
+  }
+}
+
+impl Deref for CompilerWorker {
+  type Target = Worker;
+  fn deref(&self) -> &Self::Target {
+    &self.0
+  }
+}
+
+impl DerefMut for CompilerWorker {
+  fn deref_mut(&mut self) -> &mut Self::Target {
+    &mut self.0
+  }
+}
+
+impl Future for CompilerWorker {
+  type Output = Result<(), ErrBox>;
+
+  fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
+    let inner = self.get_mut();
+    inner.0.poll_unpin(cx)
+  }
+}