| use crate::cell::UnsafeCell; |
| use crate::ptr; |
| use crate::sync::atomic::{AtomicPtr, Ordering::Relaxed}; |
| use crate::sys::locks::mutex::{self, Mutex}; |
| use crate::sys::time::TIMESPEC_MAX; |
| use crate::sys_common::lazy_box::{LazyBox, LazyInit}; |
| use crate::time::Duration; |
| |
| extern "C" { |
| pub fn pthread_cond_timedwait( |
| cond: *mut libc::pthread_cond_t, |
| lock: *mut libc::pthread_mutex_t, |
| adstime: *const libc::timespec, |
| ) -> libc::c_int; |
| } |
| |
| struct AllocatedCondvar(UnsafeCell<libc::pthread_cond_t>); |
| |
| pub struct Condvar { |
| inner: LazyBox<AllocatedCondvar>, |
| mutex: AtomicPtr<libc::pthread_mutex_t>, |
| } |
| |
| #[inline] |
| fn raw(c: &Condvar) -> *mut libc::pthread_cond_t { |
| c.inner.0.get() |
| } |
| |
| unsafe impl Send for AllocatedCondvar {} |
| unsafe impl Sync for AllocatedCondvar {} |
| |
| impl LazyInit for AllocatedCondvar { |
| fn init() -> Box<Self> { |
| let condvar = Box::new(AllocatedCondvar(UnsafeCell::new(libc::PTHREAD_COND_INITIALIZER))); |
| |
| let r = unsafe { libc::pthread_cond_init(condvar.0.get(), crate::ptr::null()) }; |
| assert_eq!(r, 0); |
| |
| condvar |
| } |
| } |
| |
| impl Drop for AllocatedCondvar { |
| #[inline] |
| fn drop(&mut self) { |
| let r = unsafe { libc::pthread_cond_destroy(self.0.get()) }; |
| debug_assert_eq!(r, 0); |
| } |
| } |
| |
| impl Condvar { |
| pub const fn new() -> Condvar { |
| Condvar { inner: LazyBox::new(), mutex: AtomicPtr::new(ptr::null_mut()) } |
| } |
| |
| #[inline] |
| fn verify(&self, mutex: *mut libc::pthread_mutex_t) { |
| match self.mutex.compare_exchange(ptr::null_mut(), mutex, Relaxed, Relaxed) { |
| Ok(_) => {} // Stored the address |
| Err(n) if n == mutex => {} // Lost a race to store the same address |
| _ => panic!("attempted to use a condition variable with two mutexes"), |
| } |
| } |
| |
| #[inline] |
| pub fn notify_one(&self) { |
| let r = unsafe { libc::pthread_cond_signal(raw(self)) }; |
| debug_assert_eq!(r, 0); |
| } |
| |
| #[inline] |
| pub fn notify_all(&self) { |
| let r = unsafe { libc::pthread_cond_broadcast(raw(self)) }; |
| debug_assert_eq!(r, 0); |
| } |
| |
| #[inline] |
| pub unsafe fn wait(&self, mutex: &Mutex) { |
| let mutex = mutex::raw(mutex); |
| self.verify(mutex); |
| let r = libc::pthread_cond_wait(raw(self), mutex); |
| debug_assert_eq!(r, 0); |
| } |
| |
| pub unsafe fn wait_timeout(&self, mutex: &Mutex, dur: Duration) -> bool { |
| use crate::sys::time::Timespec; |
| |
| let mutex = mutex::raw(mutex); |
| self.verify(mutex); |
| |
| let timeout = Timespec::now(libc::CLOCK_MONOTONIC) |
| .checked_add_duration(&dur) |
| .and_then(|t| t.to_timespec()) |
| .unwrap_or(TIMESPEC_MAX); |
| |
| let r = pthread_cond_timedwait(raw(self), mutex, &timeout); |
| assert!(r == libc::ETIMEDOUT || r == 0); |
| r == 0 |
| } |
| } |