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Diffstat (limited to 'src/thread_parker/generic.rs')
-rw-r--r-- | src/thread_parker/generic.rs | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/src/thread_parker/generic.rs b/src/thread_parker/generic.rs new file mode 100644 index 0000000..3ee837a --- /dev/null +++ b/src/thread_parker/generic.rs @@ -0,0 +1,77 @@ +// Copyright 2016 Amanieu d'Antras +// +// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or +// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or +// http://opensource.org/licenses/MIT>, at your option. This file may not be +// copied, modified, or distributed except according to those terms. + +//! A simple spin lock based thread parker. Used on platforms without better +//! parking facilities available. + +use core::sync::atomic::{spin_loop_hint, AtomicBool, Ordering}; +use std::{thread, time::Instant}; + +// Helper type for putting a thread to sleep until some other thread wakes it up +pub struct ThreadParker { + parked: AtomicBool, +} + +impl super::ThreadParkerT for ThreadParker { + type UnparkHandle = UnparkHandle; + + const IS_CHEAP_TO_CONSTRUCT: bool = true; + + #[inline] + fn new() -> ThreadParker { + ThreadParker { + parked: AtomicBool::new(false), + } + } + + #[inline] + unsafe fn prepare_park(&self) { + self.parked.store(true, Ordering::Relaxed); + } + + #[inline] + unsafe fn timed_out(&self) -> bool { + self.parked.load(Ordering::Relaxed) != false + } + + #[inline] + unsafe fn park(&self) { + while self.parked.load(Ordering::Acquire) != false { + spin_loop_hint(); + } + } + + #[inline] + unsafe fn park_until(&self, timeout: Instant) -> bool { + while self.parked.load(Ordering::Acquire) != false { + if Instant::now() >= timeout { + return false; + } + spin_loop_hint(); + } + true + } + + #[inline] + unsafe fn unpark_lock(&self) -> UnparkHandle { + // We don't need to lock anything, just clear the state + self.parked.store(false, Ordering::Release); + UnparkHandle(()) + } +} + +pub struct UnparkHandle(()); + +impl super::UnparkHandleT for UnparkHandle { + #[inline] + unsafe fn unpark(self) {} +} + +#[inline] +pub fn thread_yield() { + thread::yield_now(); +} |