move async_executor and job_token modules into new parallel module (#923)

to make parallelization related code more organized

Author: Be-ing

src/lib.rs

@@ -66,11 +66,9 @@ use std::process::{Child, Command, Stdio};
 use std::sync::{Arc, Mutex};
 use std::thread::{self, JoinHandle};
 
-#[cfg(feature = "parallel")]
-mod async_executor;
-#[cfg(feature = "parallel")]
-mod job_token;
 mod os_pipe;
+#[cfg(feature = "parallel")]
+mod parallel;
 // These modules are all glue to support reading the MSVC version from
 // the registry and from COM interfaces
 #[cfg(windows)]
@@ -1318,7 +1316,7 @@ impl Build {
     fn compile_objects(&self, objs: &[Object], print: Option<&PrintThread>) -> Result<(), Error> {
         use std::cell::Cell;
 
-        use async_executor::{block_on, YieldOnce};
+        use parallel::async_executor::{block_on, YieldOnce};
 
         if objs.len() <= 1 {
             for obj in objs {
@@ -1330,7 +1328,7 @@ impl Build {
         }
 
         // Limit our parallelism globally with a jobserver.
-        let tokens = crate::job_token::JobTokenServer::new();
+        let tokens = parallel::job_token::JobTokenServer::new();
 
         // When compiling objects in parallel we do a few dirty tricks to speed
         // things up:
@@ -1355,7 +1353,7 @@ impl Build {
             Command,
             String,
             KillOnDrop,
-            crate::job_token::JobToken,
+            parallel::job_token::JobToken,
         )>::new());
         let is_disconnected = Cell::new(false);
         let has_made_progress = Cell::new(false);

src/async_executor.rs renamed to src/parallel/async_executor.rs

@@ -23,7 +23,7 @@ const NOOP_WAKER_VTABLE: RawWakerVTable = RawWakerVTable::new(
 const NOOP_RAW_WAKER: RawWaker = RawWaker::new(ptr::null(), &NOOP_WAKER_VTABLE);
 
 #[derive(Default)]
-pub(super) struct YieldOnce(bool);
+pub(crate) struct YieldOnce(bool);
 
 impl Future for YieldOnce {
     type Output = ();
@@ -44,7 +44,7 @@ impl Future for YieldOnce {
 /// Here we use our own homebrew async executor since cc is used in the build
 /// script of many popular projects, pulling in additional dependencies would
 /// significantly slow down its compilation.
-pub(super) fn block_on<Fut1, Fut2>(
+pub(crate) fn block_on<Fut1, Fut2>(
     mut fut1: Fut1,
     mut fut2: Fut2,
     has_made_progress: &Cell<bool>,

src/job_token.rs renamed to src/parallel/job_token/mod.rs

@@ -3,14 +3,14 @@ use std::{mem::MaybeUninit, sync::Once};
 use crate::Error;
 
 #[cfg(unix)]
-#[path = "job_token/unix.rs"]
+#[path = "unix.rs"]
 mod sys;
 
 #[cfg(windows)]
-#[path = "job_token/windows.rs"]
+#[path = "windows.rs"]
 mod sys;
 
-pub(super) struct JobToken();
+pub(crate) struct JobToken();
 
 impl Drop for JobToken {
     fn drop(&mut self) {
@@ -21,7 +21,7 @@ impl Drop for JobToken {
     }
 }
 
-pub(super) enum JobTokenServer {
+pub(crate) enum JobTokenServer {
     Inherited(inherited_jobserver::JobServer),
     InProcess(inprocess_jobserver::JobServer),
 }

src/job_token/unix.rs renamed to src/parallel/job_token/unix.rs

@@ -0,0 +1,2 @@
+pub(crate) mod async_executor;
+pub(crate) mod job_token;