Remove an old custom OnceCell implementation in favor of std (#7208)

Author: a1phyr

tokio/src/loom/std/atomic_u64_static_once_cell.rs

@@ -1,10 +1,10 @@
 use super::AtomicU64;
 use crate::loom::sync::{atomic::Ordering, Mutex};
-use crate::util::once_cell::OnceCell;
+use std::sync::OnceLock;
 
 pub(crate) struct StaticAtomicU64 {
     init: u64,
-    cell: OnceCell<Mutex<u64>>,
+    cell: OnceLock<Mutex<u64>>,
 }
 
 impl AtomicU64 {
@@ -19,7 +19,7 @@ impl StaticAtomicU64 {
     pub(crate) const fn new(val: u64) -> StaticAtomicU64 {
         StaticAtomicU64 {
             init: val,
-            cell: OnceCell::new(),
+            cell: OnceLock::new(),
         }
     }
 
@@ -52,6 +52,6 @@ impl StaticAtomicU64 {
     }
 
     fn inner(&self) -> &Mutex<u64> {
-        self.cell.get(|| Mutex::new(self.init))
+        self.cell.get_or_init(|| Mutex::new(self.init))
     }
 }

tokio/src/process/unix/mod.rs

@@ -66,11 +66,11 @@ impl Kill for StdChild {
 
 cfg_not_has_const_mutex_new! {
     fn get_orphan_queue() -> &'static OrphanQueueImpl<StdChild> {
-        use crate::util::once_cell::OnceCell;
+        use std::sync::OnceLock;
 
-        static ORPHAN_QUEUE: OnceCell<OrphanQueueImpl<StdChild>> = OnceCell::new();
+        static ORPHAN_QUEUE: OnceLock<OrphanQueueImpl<StdChild>> = OnceLock::new();
 
-        ORPHAN_QUEUE.get(OrphanQueueImpl::new)
+        ORPHAN_QUEUE.get_or_init(OrphanQueueImpl::new)
     }
 }
 

tokio/src/signal/registry.rs

@@ -1,9 +1,9 @@
 use crate::signal::os::{OsExtraData, OsStorage};
 use crate::sync::watch;
-use crate::util::once_cell::OnceCell;
 
 use std::ops;
 use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::OnceLock;
 
 pub(crate) type EventId = usize;
 
@@ -164,9 +164,9 @@ where
     OsExtraData: 'static + Send + Sync + Init,
     OsStorage: 'static + Send + Sync + Init,
 {
-    static GLOBALS: OnceCell<Globals> = OnceCell::new();
+    static GLOBALS: OnceLock<Globals> = OnceLock::new();
 
-    GLOBALS.get(globals_init)
+    GLOBALS.get_or_init(globals_init)
 }
 
 #[cfg(all(test, not(loom)))]

tokio/src/util/mod.rs

@@ -13,9 +13,6 @@ pub(crate) use blocking_check::check_socket_for_blocking;
 
 pub(crate) mod metric_atomics;
 
-#[cfg(any(feature = "rt", feature = "signal", feature = "process"))]
-pub(crate) mod once_cell;
-
 #[cfg(any(
     // io driver uses `WakeList` directly
     feature = "net",