src/libstd/sys/common/condvar.rs

   1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use time::Duration;
  12 use sys_common::mutex::{self, Mutex};
  13 use sys::condvar as imp;
  14
  15 /// An OS-based condition variable.
  16 ///
  17 /// This structure is the lowest layer possible on top of the OS-provided
  18 /// condition variables. It is consequently entirely unsafe to use. It is
  19 /// recommended to use the safer types at the top level of this crate instead of
  20 /// this type.
  21 pub struct Condvar(imp::Condvar);
  22
  23 /// Static initializer for condition variables.
  24 pub const CONDVAR_INIT: Condvar = Condvar(imp::CONDVAR_INIT);
  25
  26 impl Condvar {
  27     /// Creates a new condition variable for use.
  28     ///
  29     /// Behavior is undefined if the condition variable is moved after it is
  30     /// first used with any of the functions below.
  31     #[inline]
  32     pub unsafe fn new() -> Condvar { Condvar(imp::Condvar::new()) }
  33
  34     /// Signals one waiter on this condition variable to wake up.
  35     #[inline]
  36     pub unsafe fn notify_one(&self) { self.0.notify_one() }
  37
  38     /// Awakens all current waiters on this condition variable.
  39     #[inline]
  40     pub unsafe fn notify_all(&self) { self.0.notify_all() }
  41
  42     /// Waits for a signal on the specified mutex.
  43     ///
  44     /// Behavior is undefined if the mutex is not locked by the current thread.
  45     /// Behavior is also undefined if more than one mutex is used concurrently
  46     /// on this condition variable.
  47     #[inline]
  48     pub unsafe fn wait(&self, mutex: &Mutex) { self.0.wait(mutex::raw(mutex)) }
  49
  50     /// Waits for a signal on the specified mutex with a timeout duration
  51     /// specified by `dur` (a relative time into the future).
  52     ///
  53     /// Behavior is undefined if the mutex is not locked by the current thread.
  54     /// Behavior is also undefined if more than one mutex is used concurrently
  55     /// on this condition variable.
  56     #[inline]
  57     pub unsafe fn wait_timeout(&self, mutex: &Mutex, dur: Duration) -> bool {
  58         self.0.wait_timeout(mutex::raw(mutex), dur)
  59     }
  60
  61     /// Deallocates all resources associated with this condition variable.
  62     ///
  63     /// Behavior is undefined if there are current or will be future users of
  64     /// this condition variable.
  65     #[inline]
  66     pub unsafe fn destroy(&self) { self.0.destroy() }
  67 }