From 4f2ad301f77a669780b2e0142116065e5bd11621 Mon Sep 17 00:00:00 2001
From: Dan Gohman <dev@sunfishcode.online>
Date: Tue, 27 Aug 2024 12:02:48 -0700
Subject: [PATCH] Update to rustix 0.38.35 and the new futex API. (#13)

---
 Cargo.toml       |  3 +--
 src/lib.rs       |  6 +++---
 src/wait_wake.rs | 56 ++++++++++++++----------------------------------
 3 files changed, 20 insertions(+), 45 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index ffca143..5293467 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -15,7 +15,7 @@ include = ["src", "Cargo.toml", "COPYRIGHT", "LICENSE*", "/*.md"]
 rust-version = "1.70"
 
 [dependencies]
-rustix = { version = "0.38.34", default-features = false, features = ["thread", "time"] }
+rustix = { version = "0.38.35", default-features = false, features = ["thread", "time"] }
 lock_api = { version = "0.4.7", default-features = false, optional = true }
 
 # Special dependencies used in rustc-dep-of-std mode.
@@ -38,4 +38,3 @@ rustc-dep-of-std = [
 
 [package.metadata.docs.rs]
 features = ["atomic_usize"]
-rustdoc-args = ["--cfg", "doc_cfg"]
diff --git a/src/lib.rs b/src/lib.rs
index aaf358b..956ee88 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,6 +1,6 @@
 #![doc = include_str!("../README.md")]
 #![no_std]
-#![cfg_attr(doc_cfg, feature(doc_cfg))]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 
 // Re-export this so that our users can use the same version we do.
 #[cfg(feature = "lock_api")]
@@ -29,11 +29,11 @@ pub type MappedRwLockReadGuard<'a, T> = lock_api::MappedRwLockReadGuard<'a, RawR
 pub type MappedRwLockWriteGuard<'a, T> = lock_api::MappedRwLockWriteGuard<'a, RawRwLock, T>;
 #[cfg(feature = "lock_api")]
 #[cfg(feature = "atomic_usize")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "atomic_usize")))]
+#[cfg_attr(docsrs, doc(cfg(feature = "atomic_usize")))]
 pub type ReentrantMutex<G, T> = lock_api::ReentrantMutex<RawMutex, G, T>;
 #[cfg(feature = "lock_api")]
 #[cfg(feature = "atomic_usize")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "atomic_usize")))]
+#[cfg_attr(docsrs, doc(cfg(feature = "atomic_usize")))]
 pub type ReentrantMutexGuard<'a, G, T> = lock_api::ReentrantMutexGuard<'a, RawMutex, G, T>;
 
 // Export the once types.
diff --git a/src/wait_wake.rs b/src/wait_wake.rs
index d88cfab..e9af022 100644
--- a/src/wait_wake.rs
+++ b/src/wait_wake.rs
@@ -2,9 +2,10 @@
 //! library/std/src/sys/pal/unix/futex.rs at revision
 //! b58f647d5488dce73bba517907c44af2c2a618c4.
 
+use core::num::NonZeroU32;
 use core::sync::atomic::AtomicU32;
 use core::time::Duration;
-use rustix::thread::{FutexFlags, FutexOperation};
+use rustix::thread::futex;
 use rustix::time::{ClockId, Timespec};
 
 /// Wait for a futex_wake operation to wake us.
@@ -36,7 +37,6 @@ pub fn futex_wait(futex: &AtomicU32, expected: u32, timeout: Option<Duration>) -
 /// This allows callers that don't need the timeout to pass `None` and avoid
 /// statically depending on `clock_gettime`.
 pub fn futex_wait_timespec(futex: &AtomicU32, expected: u32, timespec: Option<Timespec>) -> bool {
-    use core::ptr::{null, null_mut};
     use core::sync::atomic::Ordering::Relaxed;
 
     loop {
@@ -45,19 +45,18 @@ pub fn futex_wait_timespec(futex: &AtomicU32, expected: u32, timespec: Option<Ti
             return true;
         }
 
-        let r = unsafe {
-            // Use FUTEX_WAIT_BITSET rather than FUTEX_WAIT to be able to give an
-            // absolute time rather than a relative time.
-            rustix::thread::futex(
-                futex.as_ptr(),
-                FutexOperation::WaitBitset,
-                FutexFlags::PRIVATE,
+        let r =
+            // Use `FUTEX_WAIT_BITSET` rather than `FUTEX_WAIT` to be able to
+            // give an absolute time rather than a relative time.
+            futex::wait_bitset(
+                futex,
+                futex::Flags::PRIVATE,
                 expected,
-                timespec.as_ref().map_or(null(), |t| t as *const _),
-                null_mut(),
-                !0u32, // A full bitmask, to make it behave like a regular FUTEX_WAIT.
+                timespec,
+ // A full bitmask, to make it behave like a regular `FUTEX_WAIT`.
+                NonZeroU32::MAX
             )
-        };
+        ;
 
         match r {
             Err(rustix::io::Errno::TIMEDOUT) => return false,
@@ -72,36 +71,13 @@ pub fn futex_wait_timespec(futex: &AtomicU32, expected: u32, timespec: Option<Ti
 /// Returns true if this actually woke up such a thread,
 /// or false if no thread was waiting on this futex.
 pub fn futex_wake(futex: &AtomicU32) -> bool {
-    use core::ptr::{null, null_mut};
-    unsafe {
-        match rustix::thread::futex(
-            futex.as_ptr(),
-            FutexOperation::Wake,
-            FutexFlags::PRIVATE,
-            1,
-            null(),
-            null_mut(),
-            0,
-        ) {
-            Err(_) | Ok(0) => false,
-            _ => true,
-        }
+    match futex::wake(futex, futex::Flags::PRIVATE, 1) {
+        Err(_) | Ok(0) => false,
+        _ => true,
     }
 }
 
 /// Wake up all threads that are waiting on futex_wait on this futex.
 pub fn futex_wake_all(futex: &AtomicU32) {
-    use core::ptr::{null, null_mut};
-    unsafe {
-        rustix::thread::futex(
-            futex.as_ptr(),
-            FutexOperation::Wake,
-            FutexFlags::PRIVATE,
-            i32::MAX as u32,
-            null(),
-            null_mut(),
-            0,
-        )
-        .ok();
-    }
+    futex::wake(futex, futex::Flags::PRIVATE, i32::MAX as u32).ok();
 }