Unify id-based thread parking implementations

library/std/src/sys/sgx/mod.rs

@@ -34,7 +34,7 @@ pub mod process;
 pub mod stdio;
 pub mod thread;
 pub mod thread_local_key;
-pub mod thread_parker;
+pub mod thread_parking;
 pub mod time;
 
 mod condvar;

library/std/src/sys/sgx/thread.rs

@@ -65,9 +65,9 @@ mod task_queue {
 /// execution. The signal is sent once all TLS destructors have finished at
 /// which point no new thread locals should be created.
 pub mod wait_notify {
-    use super::super::thread_parker::Parker;
     use crate::pin::Pin;
     use crate::sync::Arc;
+    use crate::sys_common::thread_parking::Parker;
 
     pub struct Notifier(Arc<Parker>);
 
@@ -87,14 +87,14 @@ pub mod wait_notify {
         /// called, this will return immediately, otherwise the current thread
         /// is blocked until notified.
         pub fn wait(self) {
-            // This is not actually `unsafe`, but it uses the `Parker` API,
-            // which needs `unsafe` on some platforms.
+            // SAFETY:
+            // This is only ever called on one thread.
             unsafe { Pin::new(&*self.0).park() }
         }
     }
 
     pub fn new() -> (Notifier, Waiter) {
-        let inner = Arc::new(Parker::new_internal());
+        let inner = Arc::new(Parker::new());
         (Notifier(inner.clone()), Waiter(inner))
     }
 }

library/std/src/sys/sgx/thread_parking.rs

@@ -0,0 +1,23 @@
+use super::abi::usercalls;
+use crate::io::ErrorKind;
+use crate::time::Duration;
+use fortanix_sgx_abi::{EV_UNPARK, WAIT_INDEFINITE};
+
+pub type ThreadId = fortanix_sgx_abi::Tcs;
+
+pub use super::abi::thread::current;
+
+pub fn park(_hint: usize) {
+    usercalls::wait(EV_UNPARK, WAIT_INDEFINITE).unwrap();
+}
+
+pub fn park_timeout(dur: Duration, _hint: usize) {
+    let timeout = u128::min(dur.as_nanos(), WAIT_INDEFINITE as u128 - 1) as u64;
+    if let Err(e) = usercalls::wait(EV_UNPARK, timeout) {
+        assert!(matches!(e.kind(), ErrorKind::TimedOut | ErrorKind::WouldBlock))
+    }
+}
+
+pub fn unpark(tid: ThreadId, _hint: usize) {
+    let _ = usercalls::send(EV_UNPARK, Some(tid));
+}

library/std/src/sys/unix/mod.rs

@@ -40,7 +40,7 @@ pub mod stdio;
 pub mod thread;
 pub mod thread_local_dtor;
 pub mod thread_local_key;
-pub mod thread_parker;
+pub mod thread_parking;
 pub mod time;
 
 #[cfg(target_os = "espidf")]

library/std/src/sys/unix/thread_parker/darwin.rs → library/std/src/sys/unix/thread_parking/darwin.rs

@@ -46,7 +46,7 @@ unsafe impl Sync for Parker {}
 unsafe impl Send for Parker {}
 
 impl Parker {
-    pub unsafe fn new(parker: *mut Parker) {
+    pub unsafe fn new_in_place(parker: *mut Parker) {
         let semaphore = dispatch_semaphore_create(0);
         assert!(
             !semaphore.is_null(),

library/std/src/sys/unix/thread_parker/mod.rs → library/std/src/sys/unix/thread_parking/mod.rs

@@ -24,7 +24,7 @@ cfg_if::cfg_if! {
         pub use darwin::Parker;
     } else if #[cfg(target_os = "netbsd")] {
         mod netbsd;
-        pub use netbsd::Parker;
+        pub use netbsd::{current, park, park_timeout, unpark, ThreadId};
     } else {
         mod pthread;
         pub use pthread::Parker;

library/std/src/sys/unix/thread_parking/netbsd.rs

@@ -0,0 +1,52 @@
+use crate::ffi::{c_int, c_void};
+use crate::ptr;
+use crate::time::Duration;
+use libc::{_lwp_self, clockid_t, lwpid_t, time_t, timespec, CLOCK_MONOTONIC};
+
+extern "C" {
+    fn ___lwp_park60(
+        clock_id: clockid_t,
+        flags: c_int,
+        ts: *mut timespec,
+        unpark: lwpid_t,
+        hint: *const c_void,
+        unparkhint: *const c_void,
+    ) -> c_int;
+    fn _lwp_unpark(lwp: lwpid_t, hint: *const c_void) -> c_int;
+}
+
+pub type ThreadId = lwpid_t;
+
+#[inline]
+pub fn current() -> ThreadId {
+    unsafe { _lwp_self() }
+}
+
+#[inline]
+pub fn park(hint: usize) {
+    unsafe {
+        ___lwp_park60(0, 0, ptr::null_mut(), 0, ptr::invalid(hint), ptr::null());
+    }
+}
+
+pub fn park_timeout(dur: Duration, hint: usize) {
+    let mut timeout = timespec {
+        // Saturate so that the operation will definitely time out
+        // (even if it is after the heat death of the universe).
+        tv_sec: dur.as_secs().try_into().ok().unwrap_or(time_t::MAX),
+        tv_nsec: dur.subsec_nanos().into(),
+    };
+
+    // Timeout needs to be mutable since it is modified on NetBSD 9.0 and
+    // above.
+    unsafe {
+        ___lwp_park60(CLOCK_MONOTONIC, 0, &mut timeout, 0, ptr::invalid(hint), ptr::null());
+    }
+}
+
+#[inline]
+pub fn unpark(tid: ThreadId, hint: usize) {
+    unsafe {
+        _lwp_unpark(tid, ptr::invalid(hint));
+    }
+}

library/std/src/sys/unix/thread_parker/pthread.rs → library/std/src/sys/unix/thread_parking/pthread.rs

@@ -99,7 +99,7 @@ impl Parker {
     ///
     /// # Safety
     /// The constructed parker must never be moved.
-    pub unsafe fn new(parker: *mut Parker) {
+    pub unsafe fn new_in_place(parker: *mut Parker) {
         // Use the default mutex implementation to allow for simpler initialization.
         // This could lead to undefined behaviour when deadlocking. This is avoided
         // by not deadlocking. Note in particular the unlocking operation before any

library/std/src/sys/windows/mod.rs

@@ -33,7 +33,7 @@ pub mod stdio;
 pub mod thread;
 pub mod thread_local_dtor;
 pub mod thread_local_key;
-pub mod thread_parker;
+pub mod thread_parking;
 pub mod time;
 cfg_if::cfg_if! {
     if #[cfg(not(target_vendor = "uwp"))] {

library/std/src/sys/windows/thread_parker.rs → library/std/src/sys/windows/thread_parking.rs

@@ -97,7 +97,7 @@ const NOTIFIED: i8 = 1;
 impl Parker {
     /// Construct the Windows parker. The UNIX parker implementation
     /// requires this to happen in-place.
-    pub unsafe fn new(parker: *mut Parker) {
+    pub unsafe fn new_in_place(parker: *mut Parker) {
         parker.write(Self { state: AtomicI8::new(EMPTY) });
     }
 

library/std/src/sys_common/mod.rs

@@ -30,7 +30,7 @@ pub mod process;
 pub mod thread;
 pub mod thread_info;
 pub mod thread_local_dtor;
-pub mod thread_parker;
+pub mod thread_parking;
 pub mod wstr;
 pub mod wtf8;