-// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.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.
-
-use prelude::v1::*;
-
-use sync::atomic::{AtomicUsize, Ordering, ATOMIC_USIZE_INIT};
-use sync::poison::{self, LockResult};
-use sys::time::SteadyTime;
-use sys_common::condvar as sys;
-use sys_common::mutex as sys_mutex;
-use time::Duration;
-use sync::{mutex, MutexGuard, PoisonError};
+use crate::fmt;
+use crate::sync::atomic::{AtomicUsize, Ordering};
+use crate::sync::{mutex, MutexGuard, PoisonError};
+use crate::sys_common::condvar as sys;
+use crate::sys_common::mutex as sys_mutex;
+use crate::sys_common::poison::{self, LockResult};
+use crate::time::{Duration, Instant};
+
+/// A type indicating whether a timed wait on a condition variable returned
+/// due to a time out or not.
+///
+/// It is returned by the [`wait_timeout`] method.
+///
+/// [`wait_timeout`]: struct.Condvar.html#method.wait_timeout
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+#[stable(feature = "wait_timeout", since = "1.5.0")]
+pub struct WaitTimeoutResult(bool);
+
+impl WaitTimeoutResult {
+ /// Returns `true` if the wait was known to have timed out.
+ ///
+ /// # Examples
+ ///
+ /// This example spawns a thread which will update the boolean value and
+ /// then wait 100 milliseconds before notifying the condvar.
+ ///
+ /// The main thread will wait with a timeout on the condvar and then leave
+ /// once the boolean has been updated and notified.
+ ///
+ /// ```
+ /// use std::sync::{Arc, Condvar, Mutex};
+ /// use std::thread;
+ /// use std::time::Duration;
+ ///
+ /// let pair = Arc::new((Mutex::new(false), Condvar::new()));
+ /// let pair2 = pair.clone();
+ ///
+ /// thread::spawn(move || {
+ /// let (lock, cvar) = &*pair2;
+ ///
+ /// // Let's wait 20 milliseconds before notifying the condvar.
+ /// thread::sleep(Duration::from_millis(20));
+ ///
+ /// let mut started = lock.lock().unwrap();
+ /// // We update the boolean value.
+ /// *started = true;
+ /// cvar.notify_one();
+ /// });
+ ///
+ /// // Wait for the thread to start up.
+ /// let (lock, cvar) = &*pair;
+ /// let mut started = lock.lock().unwrap();
+ /// loop {
+ /// // Let's put a timeout on the condvar's wait.
+ /// let result = cvar.wait_timeout(started, Duration::from_millis(10)).unwrap();
+ /// // 10 milliseconds have passed, or maybe the value changed!
+ /// started = result.0;
+ /// if *started == true {
+ /// // We received the notification and the value has been updated, we can leave.
+ /// break
+ /// }
+ /// }
+ /// ```
+ #[stable(feature = "wait_timeout", since = "1.5.0")]
+ pub fn timed_out(&self) -> bool {
+ self.0
+ }
+}
/// A Condition Variable
///
/// consumes no CPU time while waiting for an event to occur. Condition
/// variables are typically associated with a boolean predicate (a condition)
/// and a mutex. The predicate is always verified inside of the mutex before
-/// determining that thread must block.
+/// determining that a thread must block.
///
/// Functions in this module will block the current **thread** of execution and
/// are bindings to system-provided condition variables where possible. Note
/// let pair = Arc::new((Mutex::new(false), Condvar::new()));
/// let pair2 = pair.clone();
///
-/// // Inside of our lock, spawn a new thread, and then wait for it to start
+/// // Inside of our lock, spawn a new thread, and then wait for it to start.
/// thread::spawn(move|| {
-/// let &(ref lock, ref cvar) = &*pair2;
+/// let (lock, cvar) = &*pair2;
/// let mut started = lock.lock().unwrap();
/// *started = true;
+/// // We notify the condvar that the value has changed.
/// cvar.notify_one();
/// });
///
-/// // wait for the thread to start up
-/// let &(ref lock, ref cvar) = &*pair;
+/// // Wait for the thread to start up.
+/// let (lock, cvar) = &*pair;
/// let mut started = lock.lock().unwrap();
/// while !*started {
/// started = cvar.wait(started).unwrap();
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Condvar { inner: Box<StaticCondvar> }
-
-/// Statically allocated condition variables.
-///
-/// This structure is identical to `Condvar` except that it is suitable for use
-/// in static initializers for other structures.
-///
-/// # Examples
-///
-/// ```
-/// # #![feature(std_misc)]
-/// use std::sync::{StaticCondvar, CONDVAR_INIT};
-///
-/// static CVAR: StaticCondvar = CONDVAR_INIT;
-/// ```
-#[unstable(feature = "std_misc",
- reason = "may be merged with Condvar in the future")]
-pub struct StaticCondvar {
- inner: sys::Condvar,
+pub struct Condvar {
+ inner: Box<sys::Condvar>,
mutex: AtomicUsize,
}
-/// Constant initializer for a statically allocated condition variable.
-#[unstable(feature = "std_misc",
- reason = "may be merged with Condvar in the future")]
-pub const CONDVAR_INIT: StaticCondvar = StaticCondvar {
- inner: sys::CONDVAR_INIT,
- mutex: ATOMIC_USIZE_INIT,
-};
-
impl Condvar {
/// Creates a new condition variable which is ready to be waited on and
/// notified.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::sync::Condvar;
+ ///
+ /// let condvar = Condvar::new();
+ /// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn new() -> Condvar {
- Condvar {
- inner: box StaticCondvar {
- inner: unsafe { sys::Condvar::new() },
- mutex: AtomicUsize::new(0),
- }
+ let mut c = Condvar { inner: box sys::Condvar::new(), mutex: AtomicUsize::new(0) };
+ unsafe {
+ c.inner.init();
}
+ c
}
- /// Block the current thread until this condition variable receives a
+ /// Blocks the current thread until this condition variable receives a
/// notification.
///
/// This function will atomically unlock the mutex specified (represented by
- /// `mutex_guard`) and block the current thread. This means that any calls
- /// to `notify_*()` which happen logically after the mutex is unlocked are
- /// candidates to wake this thread up. When this function call returns, the
- /// lock specified will have been re-acquired.
+ /// `guard`) and block the current thread. This means that any calls
+ /// to [`notify_one`] or [`notify_all`] which happen logically after the
+ /// mutex is unlocked are candidates to wake this thread up. When this
+ /// function call returns, the lock specified will have been re-acquired.
///
/// Note that this function is susceptible to spurious wakeups. Condition
/// variables normally have a boolean predicate associated with them, and
/// the predicate must always be checked each time this function returns to
/// protect against spurious wakeups.
///
- /// # Failure
+ /// # Errors
///
/// This function will return an error if the mutex being waited on is
/// poisoned when this thread re-acquires the lock. For more information,
- /// see information about poisoning on the Mutex type.
+ /// see information about [poisoning] on the [`Mutex`] type.
///
/// # Panics
///
- /// This function will `panic!()` if it is used with more than one mutex
+ /// This function will [`panic!`] if it is used with more than one mutex
/// over time. Each condition variable is dynamically bound to exactly one
/// mutex to ensure defined behavior across platforms. If this functionality
/// is not desired, then unsafe primitives in `sys` are provided.
+ ///
+ /// [`notify_one`]: #method.notify_one
+ /// [`notify_all`]: #method.notify_all
+ /// [poisoning]: ../sync/struct.Mutex.html#poisoning
+ /// [`Mutex`]: ../sync/struct.Mutex.html
+ /// [`panic!`]: ../../std/macro.panic.html
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::sync::{Arc, Mutex, Condvar};
+ /// use std::thread;
+ ///
+ /// let pair = Arc::new((Mutex::new(false), Condvar::new()));
+ /// let pair2 = pair.clone();
+ ///
+ /// thread::spawn(move|| {
+ /// let (lock, cvar) = &*pair2;
+ /// let mut started = lock.lock().unwrap();
+ /// *started = true;
+ /// // We notify the condvar that the value has changed.
+ /// cvar.notify_one();
+ /// });
+ ///
+ /// // Wait for the thread to start up.
+ /// let (lock, cvar) = &*pair;
+ /// let mut started = lock.lock().unwrap();
+ /// // As long as the value inside the `Mutex<bool>` is `false`, we wait.
+ /// while !*started {
+ /// started = cvar.wait(started).unwrap();
+ /// }
+ /// ```
#[stable(feature = "rust1", since = "1.0.0")]
- pub fn wait<'a, T>(&self, guard: MutexGuard<'a, T>)
- -> LockResult<MutexGuard<'a, T>> {
- unsafe {
- let me: &'static Condvar = &*(self as *const _);
- me.inner.wait(guard)
+ pub fn wait<'a, T>(&self, guard: MutexGuard<'a, T>) -> LockResult<MutexGuard<'a, T>> {
+ let poisoned = unsafe {
+ let lock = mutex::guard_lock(&guard);
+ self.verify(lock);
+ self.inner.wait(lock);
+ mutex::guard_poison(&guard).get()
+ };
+ if poisoned { Err(PoisonError::new(guard)) } else { Ok(guard) }
+ }
+
+ /// Blocks the current thread until this condition variable receives a
+ /// notification and the provided condition is false.
+ ///
+ /// This function will atomically unlock the mutex specified (represented by
+ /// `guard`) and block the current thread. This means that any calls
+ /// to [`notify_one`] or [`notify_all`] which happen logically after the
+ /// mutex is unlocked are candidates to wake this thread up. When this
+ /// function call returns, the lock specified will have been re-acquired.
+ ///
+ /// # Errors
+ ///
+ /// This function will return an error if the mutex being waited on is
+ /// poisoned when this thread re-acquires the lock. For more information,
+ /// see information about [poisoning] on the [`Mutex`] type.
+ ///
+ /// [`notify_one`]: #method.notify_one
+ /// [`notify_all`]: #method.notify_all
+ /// [poisoning]: ../sync/struct.Mutex.html#poisoning
+ /// [`Mutex`]: ../sync/struct.Mutex.html
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::sync::{Arc, Mutex, Condvar};
+ /// use std::thread;
+ ///
+ /// let pair = Arc::new((Mutex::new(true), Condvar::new()));
+ /// let pair2 = pair.clone();
+ ///
+ /// thread::spawn(move|| {
+ /// let (lock, cvar) = &*pair2;
+ /// let mut pending = lock.lock().unwrap();
+ /// *pending = false;
+ /// // We notify the condvar that the value has changed.
+ /// cvar.notify_one();
+ /// });
+ ///
+ /// // Wait for the thread to start up.
+ /// let (lock, cvar) = &*pair;
+ /// // As long as the value inside the `Mutex<bool>` is `true`, we wait.
+ /// let _guard = cvar.wait_while(lock.lock().unwrap(), |pending| { *pending }).unwrap();
+ /// ```
+ #[stable(feature = "wait_until", since = "1.42.0")]
+ pub fn wait_while<'a, T, F>(
+ &self,
+ mut guard: MutexGuard<'a, T>,
+ mut condition: F,
+ ) -> LockResult<MutexGuard<'a, T>>
+ where
+ F: FnMut(&mut T) -> bool,
+ {
+ while condition(&mut *guard) {
+ guard = self.wait(guard)?;
}
+ Ok(guard)
}
- /// Wait on this condition variable for a notification, timing out after a
+ /// Waits on this condition variable for a notification, timing out after a
/// specified duration.
///
- /// The semantics of this function are equivalent to `wait()`
+ /// The semantics of this function are equivalent to [`wait`]
/// except that the thread will be blocked for roughly no longer
/// than `ms` milliseconds. This method should not be used for
/// precise timing due to anomalies such as preemption or platform
/// differences that may not cause the maximum amount of time
/// waited to be precisely `ms`.
///
+ /// Note that the best effort is made to ensure that the time waited is
+ /// measured with a monotonic clock, and not affected by the changes made to
+ /// the system time.
+ ///
/// The returned boolean is `false` only if the timeout is known
/// to have elapsed.
///
- /// Like `wait`, the lock specified will be re-acquired when this function
+ /// Like [`wait`], the lock specified will be re-acquired when this function
/// returns, regardless of whether the timeout elapsed or not.
+ ///
+ /// [`wait`]: #method.wait
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::sync::{Arc, Mutex, Condvar};
+ /// use std::thread;
+ ///
+ /// let pair = Arc::new((Mutex::new(false), Condvar::new()));
+ /// let pair2 = pair.clone();
+ ///
+ /// thread::spawn(move|| {
+ /// let (lock, cvar) = &*pair2;
+ /// let mut started = lock.lock().unwrap();
+ /// *started = true;
+ /// // We notify the condvar that the value has changed.
+ /// cvar.notify_one();
+ /// });
+ ///
+ /// // Wait for the thread to start up.
+ /// let (lock, cvar) = &*pair;
+ /// let mut started = lock.lock().unwrap();
+ /// // As long as the value inside the `Mutex<bool>` is `false`, we wait.
+ /// loop {
+ /// let result = cvar.wait_timeout_ms(started, 10).unwrap();
+ /// // 10 milliseconds have passed, or maybe the value changed!
+ /// started = result.0;
+ /// if *started == true {
+ /// // We received the notification and the value has been updated, we can leave.
+ /// break
+ /// }
+ /// }
+ /// ```
#[stable(feature = "rust1", since = "1.0.0")]
- pub fn wait_timeout_ms<'a, T>(&self, guard: MutexGuard<'a, T>, ms: u32)
- -> LockResult<(MutexGuard<'a, T>, bool)> {
- unsafe {
- let me: &'static Condvar = &*(self as *const _);
- me.inner.wait_timeout_ms(guard, ms)
- }
+ #[rustc_deprecated(since = "1.6.0", reason = "replaced by `std::sync::Condvar::wait_timeout`")]
+ pub fn wait_timeout_ms<'a, T>(
+ &self,
+ guard: MutexGuard<'a, T>,
+ ms: u32,
+ ) -> LockResult<(MutexGuard<'a, T>, bool)> {
+ let res = self.wait_timeout(guard, Duration::from_millis(ms as u64));
+ poison::map_result(res, |(a, b)| (a, !b.timed_out()))
}
- /// Deprecated: use `wait_timeout_ms` instead.
- #[unstable(feature = "std_misc")]
- #[deprecated(since = "1.0.0", reason = "use wait_timeout_ms instead")]
- pub fn wait_timeout<'a, T>(&self, guard: MutexGuard<'a, T>, dur: Duration)
- -> LockResult<(MutexGuard<'a, T>, bool)> {
- self.wait_timeout_ms(guard, dur.num_milliseconds() as u32)
+ /// Waits on this condition variable for a notification, timing out after a
+ /// specified duration.
+ ///
+ /// The semantics of this function are equivalent to [`wait`] except that
+ /// the thread will be blocked for roughly no longer than `dur`. This
+ /// method should not be used for precise timing due to anomalies such as
+ /// preemption or platform differences that may not cause the maximum
+ /// amount of time waited to be precisely `dur`.
+ ///
+ /// Note that the best effort is made to ensure that the time waited is
+ /// measured with a monotonic clock, and not affected by the changes made to
+ /// the system time. This function is susceptible to spurious wakeups.
+ /// Condition variables normally have a boolean predicate associated with
+ /// them, and the predicate must always be checked each time this function
+ /// returns to protect against spurious wakeups. Additionally, it is
+ /// typically desirable for the timeout to not exceed some duration in
+ /// spite of spurious wakes, thus the sleep-duration is decremented by the
+ /// amount slept. Alternatively, use the `wait_timeout_while` method
+ /// to wait with a timeout while a predicate is true.
+ ///
+ /// The returned [`WaitTimeoutResult`] value indicates if the timeout is
+ /// known to have elapsed.
+ ///
+ /// Like [`wait`], the lock specified will be re-acquired when this function
+ /// returns, regardless of whether the timeout elapsed or not.
+ ///
+ /// [`wait`]: #method.wait
+ /// [`wait_timeout_while`]: #method.wait_timeout_while
+ /// [`WaitTimeoutResult`]: struct.WaitTimeoutResult.html
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::sync::{Arc, Mutex, Condvar};
+ /// use std::thread;
+ /// use std::time::Duration;
+ ///
+ /// let pair = Arc::new((Mutex::new(false), Condvar::new()));
+ /// let pair2 = pair.clone();
+ ///
+ /// thread::spawn(move|| {
+ /// let (lock, cvar) = &*pair2;
+ /// let mut started = lock.lock().unwrap();
+ /// *started = true;
+ /// // We notify the condvar that the value has changed.
+ /// cvar.notify_one();
+ /// });
+ ///
+ /// // wait for the thread to start up
+ /// let (lock, cvar) = &*pair;
+ /// let mut started = lock.lock().unwrap();
+ /// // as long as the value inside the `Mutex<bool>` is `false`, we wait
+ /// loop {
+ /// let result = cvar.wait_timeout(started, Duration::from_millis(10)).unwrap();
+ /// // 10 milliseconds have passed, or maybe the value changed!
+ /// started = result.0;
+ /// if *started == true {
+ /// // We received the notification and the value has been updated, we can leave.
+ /// break
+ /// }
+ /// }
+ /// ```
+ #[stable(feature = "wait_timeout", since = "1.5.0")]
+ pub fn wait_timeout<'a, T>(
+ &self,
+ guard: MutexGuard<'a, T>,
+ dur: Duration,
+ ) -> LockResult<(MutexGuard<'a, T>, WaitTimeoutResult)> {
+ let (poisoned, result) = unsafe {
+ let lock = mutex::guard_lock(&guard);
+ self.verify(lock);
+ let success = self.inner.wait_timeout(lock, dur);
+ (mutex::guard_poison(&guard).get(), WaitTimeoutResult(!success))
+ };
+ if poisoned { Err(PoisonError::new((guard, result))) } else { Ok((guard, result)) }
}
- /// Wait on this condition variable for a notification, timing out after a
+ /// Waits on this condition variable for a notification, timing out after a
/// specified duration.
///
- /// The semantics of this function are equivalent to `wait_timeout` except
- /// that the implementation will repeatedly wait while the duration has not
- /// passed and the provided function returns `false`.
- #[unstable(feature = "wait_timeout_with",
- reason = "unsure if this API is broadly needed or what form it should take")]
- pub fn wait_timeout_with<'a, T, F>(&self,
- guard: MutexGuard<'a, T>,
- dur: Duration,
- f: F)
- -> LockResult<(MutexGuard<'a, T>, bool)>
- where F: FnMut(LockResult<&mut T>) -> bool {
- unsafe {
- let me: &'static Condvar = &*(self as *const _);
- me.inner.wait_timeout_with(guard, dur, f)
+ /// The semantics of this function are equivalent to [`wait_while`] except
+ /// that the thread will be blocked for roughly no longer than `dur`. This
+ /// method should not be used for precise timing due to anomalies such as
+ /// preemption or platform differences that may not cause the maximum
+ /// amount of time waited to be precisely `dur`.
+ ///
+ /// Note that the best effort is made to ensure that the time waited is
+ /// measured with a monotonic clock, and not affected by the changes made to
+ /// the system time.
+ ///
+ /// The returned [`WaitTimeoutResult`] value indicates if the timeout is
+ /// known to have elapsed without the condition being met.
+ ///
+ /// Like [`wait_while`], the lock specified will be re-acquired when this
+ /// function returns, regardless of whether the timeout elapsed or not.
+ ///
+ /// [`wait_while`]: #method.wait_while
+ /// [`wait_timeout`]: #method.wait_timeout
+ /// [`WaitTimeoutResult`]: struct.WaitTimeoutResult.html
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::sync::{Arc, Mutex, Condvar};
+ /// use std::thread;
+ /// use std::time::Duration;
+ ///
+ /// let pair = Arc::new((Mutex::new(true), Condvar::new()));
+ /// let pair2 = pair.clone();
+ ///
+ /// thread::spawn(move|| {
+ /// let (lock, cvar) = &*pair2;
+ /// let mut pending = lock.lock().unwrap();
+ /// *pending = false;
+ /// // We notify the condvar that the value has changed.
+ /// cvar.notify_one();
+ /// });
+ ///
+ /// // wait for the thread to start up
+ /// let (lock, cvar) = &*pair;
+ /// let result = cvar.wait_timeout_while(
+ /// lock.lock().unwrap(),
+ /// Duration::from_millis(100),
+ /// |&mut pending| pending,
+ /// ).unwrap();
+ /// if result.1.timed_out() {
+ /// // timed-out without the condition ever evaluating to false.
+ /// }
+ /// // access the locked mutex via result.0
+ /// ```
+ #[stable(feature = "wait_timeout_until", since = "1.42.0")]
+ pub fn wait_timeout_while<'a, T, F>(
+ &self,
+ mut guard: MutexGuard<'a, T>,
+ dur: Duration,
+ mut condition: F,
+ ) -> LockResult<(MutexGuard<'a, T>, WaitTimeoutResult)>
+ where
+ F: FnMut(&mut T) -> bool,
+ {
+ let start = Instant::now();
+ loop {
+ if !condition(&mut *guard) {
+ return Ok((guard, WaitTimeoutResult(false)));
+ }
+ let timeout = match dur.checked_sub(start.elapsed()) {
+ Some(timeout) => timeout,
+ None => return Ok((guard, WaitTimeoutResult(true))),
+ };
+ guard = self.wait_timeout(guard, timeout)?.0;
}
}
- /// Wake up one blocked thread on this condvar.
+ /// Wakes up one blocked thread on this condvar.
///
/// If there is a blocked thread on this condition variable, then it will
- /// be woken up from its call to `wait` or `wait_timeout`. Calls to
+ /// be woken up from its call to [`wait`] or [`wait_timeout`]. Calls to
/// `notify_one` are not buffered in any way.
///
- /// To wake up all threads, see `notify_all()`.
+ /// To wake up all threads, see [`notify_all`].
+ ///
+ /// [`wait`]: #method.wait
+ /// [`wait_timeout`]: #method.wait_timeout
+ /// [`notify_all`]: #method.notify_all
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::sync::{Arc, Mutex, Condvar};
+ /// use std::thread;
+ ///
+ /// let pair = Arc::new((Mutex::new(false), Condvar::new()));
+ /// let pair2 = pair.clone();
+ ///
+ /// thread::spawn(move|| {
+ /// let (lock, cvar) = &*pair2;
+ /// let mut started = lock.lock().unwrap();
+ /// *started = true;
+ /// // We notify the condvar that the value has changed.
+ /// cvar.notify_one();
+ /// });
+ ///
+ /// // Wait for the thread to start up.
+ /// let (lock, cvar) = &*pair;
+ /// let mut started = lock.lock().unwrap();
+ /// // As long as the value inside the `Mutex<bool>` is `false`, we wait.
+ /// while !*started {
+ /// started = cvar.wait(started).unwrap();
+ /// }
+ /// ```
#[stable(feature = "rust1", since = "1.0.0")]
- pub fn notify_one(&self) { unsafe { self.inner.inner.notify_one() } }
+ pub fn notify_one(&self) {
+ unsafe { self.inner.notify_one() }
+ }
- /// Wake up all blocked threads on this condvar.
+ /// Wakes up all blocked threads on this condvar.
///
/// This method will ensure that any current waiters on the condition
/// variable are awoken. Calls to `notify_all()` are not buffered in any
/// way.
///
- /// To wake up only one thread, see `notify_one()`.
- #[stable(feature = "rust1", since = "1.0.0")]
- pub fn notify_all(&self) { unsafe { self.inner.inner.notify_all() } }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Drop for Condvar {
- fn drop(&mut self) {
- unsafe { self.inner.inner.destroy() }
- }
-}
-
-impl StaticCondvar {
- /// Block the current thread until this condition variable receives a
- /// notification.
+ /// To wake up only one thread, see [`notify_one`].
///
- /// See `Condvar::wait`.
- #[unstable(feature = "std_misc",
- reason = "may be merged with Condvar in the future")]
- pub fn wait<'a, T>(&'static self, guard: MutexGuard<'a, T>)
- -> LockResult<MutexGuard<'a, T>> {
- let poisoned = unsafe {
- let lock = mutex::guard_lock(&guard);
- self.verify(lock);
- self.inner.wait(lock);
- mutex::guard_poison(&guard).get()
- };
- if poisoned {
- Err(PoisonError::new(guard))
- } else {
- Ok(guard)
- }
- }
-
- /// Wait on this condition variable for a notification, timing out after a
- /// specified duration.
+ /// [`notify_one`]: #method.notify_one
///
- /// See `Condvar::wait_timeout`.
- #[unstable(feature = "std_misc",
- reason = "may be merged with Condvar in the future")]
- pub fn wait_timeout_ms<'a, T>(&'static self, guard: MutexGuard<'a, T>, ms: u32)
- -> LockResult<(MutexGuard<'a, T>, bool)> {
- let (poisoned, success) = unsafe {
- let lock = mutex::guard_lock(&guard);
- self.verify(lock);
- let success = self.inner.wait_timeout(lock, Duration::milliseconds(ms as i64));
- (mutex::guard_poison(&guard).get(), success)
- };
- if poisoned {
- Err(PoisonError::new((guard, success)))
- } else {
- Ok((guard, success))
- }
- }
-
- /// Wait on this condition variable for a notification, timing out after a
- /// specified duration.
+ /// # Examples
///
- /// The implementation will repeatedly wait while the duration has not
- /// passed and the function returns `false`.
- ///
- /// See `Condvar::wait_timeout_with`.
- #[unstable(feature = "std_misc",
- reason = "may be merged with Condvar in the future")]
- pub fn wait_timeout_with<'a, T, F>(&'static self,
- guard: MutexGuard<'a, T>,
- dur: Duration,
- mut f: F)
- -> LockResult<(MutexGuard<'a, T>, bool)>
- where F: FnMut(LockResult<&mut T>) -> bool {
- // This could be made more efficient by pushing the implementation into sys::condvar
- let start = SteadyTime::now();
- let mut guard_result: LockResult<MutexGuard<'a, T>> = Ok(guard);
- while !f(guard_result
- .as_mut()
- .map(|g| &mut **g)
- .map_err(|e| PoisonError::new(&mut **e.get_mut()))) {
- let now = SteadyTime::now();
- let consumed = &now - &start;
- let guard = guard_result.unwrap_or_else(|e| e.into_inner());
- let res = self.wait_timeout_ms(guard, (dur - consumed).num_milliseconds() as u32);
- let (new_guard_result, no_timeout) = match res {
- Ok((new_guard, no_timeout)) => (Ok(new_guard), no_timeout),
- Err(err) => {
- let (new_guard, no_timeout) = err.into_inner();
- (Err(PoisonError::new(new_guard)), no_timeout)
- }
- };
- guard_result = new_guard_result;
- if !no_timeout {
- let result = f(guard_result
- .as_mut()
- .map(|g| &mut **g)
- .map_err(|e| PoisonError::new(&mut **e.get_mut())));
- return poison::map_result(guard_result, |g| (g, result));
- }
- }
-
- poison::map_result(guard_result, |g| (g, true))
- }
-
- /// Wake up one blocked thread on this condvar.
+ /// ```
+ /// use std::sync::{Arc, Mutex, Condvar};
+ /// use std::thread;
///
- /// See `Condvar::notify_one`.
- #[unstable(feature = "std_misc",
- reason = "may be merged with Condvar in the future")]
- pub fn notify_one(&'static self) { unsafe { self.inner.notify_one() } }
-
- /// Wake up all blocked threads on this condvar.
+ /// let pair = Arc::new((Mutex::new(false), Condvar::new()));
+ /// let pair2 = pair.clone();
///
- /// See `Condvar::notify_all`.
- #[unstable(feature = "std_misc",
- reason = "may be merged with Condvar in the future")]
- pub fn notify_all(&'static self) { unsafe { self.inner.notify_all() } }
-
- /// Deallocate all resources associated with this static condvar.
+ /// thread::spawn(move|| {
+ /// let (lock, cvar) = &*pair2;
+ /// let mut started = lock.lock().unwrap();
+ /// *started = true;
+ /// // We notify the condvar that the value has changed.
+ /// cvar.notify_all();
+ /// });
///
- /// This method is unsafe to call as there is no guarantee that there are no
- /// active users of the condvar, and this also doesn't prevent any future
- /// users of the condvar. This method is required to be called to not leak
- /// memory on all platforms.
- #[unstable(feature = "std_misc",
- reason = "may be merged with Condvar in the future")]
- pub unsafe fn destroy(&'static self) {
- self.inner.destroy()
+ /// // Wait for the thread to start up.
+ /// let (lock, cvar) = &*pair;
+ /// let mut started = lock.lock().unwrap();
+ /// // As long as the value inside the `Mutex<bool>` is `false`, we wait.
+ /// while !*started {
+ /// started = cvar.wait(started).unwrap();
+ /// }
+ /// ```
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn notify_all(&self) {
+ unsafe { self.inner.notify_all() }
}
fn verify(&self, mutex: &sys_mutex::Mutex) {
// Anything else and we're using more than one mutex on this cvar,
// which is currently disallowed.
- _ => panic!("attempted to use a condition variable with two \
- mutexes"),
+ _ => panic!(
+ "attempted to use a condition variable with two \
+ mutexes"
+ ),
}
}
}
+#[stable(feature = "std_debug", since = "1.16.0")]
+impl fmt::Debug for Condvar {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.pad("Condvar { .. }")
+ }
+}
+
+#[stable(feature = "condvar_default", since = "1.10.0")]
+impl Default for Condvar {
+ /// Creates a `Condvar` which is ready to be waited on and notified.
+ fn default() -> Condvar {
+ Condvar::new()
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Drop for Condvar {
+ fn drop(&mut self) {
+ unsafe { self.inner.destroy() }
+ }
+}
+
#[cfg(test)]
mod tests {
- use prelude::v1::*;
-
- use super::{StaticCondvar, CONDVAR_INIT};
- use sync::mpsc::channel;
- use sync::{StaticMutex, MUTEX_INIT, Condvar, Mutex, Arc};
- use sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
- use thread;
- use time::Duration;
- use u32;
+ use crate::sync::atomic::{AtomicBool, Ordering};
+ use crate::sync::mpsc::channel;
+ use crate::sync::{Arc, Condvar, Mutex};
+ use crate::thread;
+ use crate::time::Duration;
#[test]
fn smoke() {
}
#[test]
- fn static_smoke() {
- static C: StaticCondvar = CONDVAR_INIT;
- C.notify_one();
- C.notify_all();
- unsafe { C.destroy(); }
- }
-
- #[test]
+ #[cfg_attr(target_os = "emscripten", ignore)]
fn notify_one() {
- static C: StaticCondvar = CONDVAR_INIT;
- static M: StaticMutex = MUTEX_INIT;
+ let m = Arc::new(Mutex::new(()));
+ let m2 = m.clone();
+ let c = Arc::new(Condvar::new());
+ let c2 = c.clone();
- let g = M.lock().unwrap();
- let _t = thread::spawn(move|| {
- let _g = M.lock().unwrap();
- C.notify_one();
+ let g = m.lock().unwrap();
+ let _t = thread::spawn(move || {
+ let _g = m2.lock().unwrap();
+ c2.notify_one();
});
- let g = C.wait(g).unwrap();
+ let g = c.wait(g).unwrap();
drop(g);
- unsafe { C.destroy(); M.destroy(); }
}
#[test]
+ #[cfg_attr(target_os = "emscripten", ignore)]
fn notify_all() {
const N: usize = 10;
for _ in 0..N {
let data = data.clone();
let tx = tx.clone();
- thread::spawn(move|| {
+ thread::spawn(move || {
let &(ref lock, ref cond) = &*data;
let mut cnt = lock.lock().unwrap();
*cnt += 1;
}
#[test]
- fn wait_timeout_ms() {
- static C: StaticCondvar = CONDVAR_INIT;
- static M: StaticMutex = MUTEX_INIT;
-
- let g = M.lock().unwrap();
- let (g, _no_timeout) = C.wait_timeout_ms(g, 1).unwrap();
- // spurious wakeups mean this isn't necessarily true
- // assert!(!no_timeout);
- let _t = thread::spawn(move || {
- let _g = M.lock().unwrap();
- C.notify_one();
+ #[cfg_attr(target_os = "emscripten", ignore)]
+ fn wait_while() {
+ let pair = Arc::new((Mutex::new(false), Condvar::new()));
+ let pair2 = pair.clone();
+
+ // Inside of our lock, spawn a new thread, and then wait for it to start.
+ thread::spawn(move || {
+ let &(ref lock, ref cvar) = &*pair2;
+ let mut started = lock.lock().unwrap();
+ *started = true;
+ // We notify the condvar that the value has changed.
+ cvar.notify_one();
});
- let (g, no_timeout) = C.wait_timeout_ms(g, u32::MAX).unwrap();
- assert!(no_timeout);
- drop(g);
- unsafe { C.destroy(); M.destroy(); }
+
+ // Wait for the thread to start up.
+ let &(ref lock, ref cvar) = &*pair;
+ let guard = cvar.wait_while(lock.lock().unwrap(), |started| !*started);
+ assert!(*guard.unwrap());
}
#[test]
- fn wait_timeout_with() {
- static C: StaticCondvar = CONDVAR_INIT;
- static M: StaticMutex = MUTEX_INIT;
- static S: AtomicUsize = ATOMIC_USIZE_INIT;
+ #[cfg_attr(target_os = "emscripten", ignore)]
+ #[cfg_attr(target_env = "sgx", ignore)] // FIXME: https://github.com/fortanix/rust-sgx/issues/31
+ fn wait_timeout_wait() {
+ let m = Arc::new(Mutex::new(()));
+ let c = Arc::new(Condvar::new());
+
+ loop {
+ let g = m.lock().unwrap();
+ let (_g, no_timeout) = c.wait_timeout(g, Duration::from_millis(1)).unwrap();
+ // spurious wakeups mean this isn't necessarily true
+ // so execute test again, if not timeout
+ if !no_timeout.timed_out() {
+ continue;
+ }
- let g = M.lock().unwrap();
- let (g, success) = C.wait_timeout_with(g, Duration::nanoseconds(1000), |_| false).unwrap();
- assert!(!success);
+ break;
+ }
+ }
- let (tx, rx) = channel();
- let _t = thread::spawn(move || {
- rx.recv().unwrap();
- let g = M.lock().unwrap();
- S.store(1, Ordering::SeqCst);
- C.notify_one();
- drop(g);
+ #[test]
+ #[cfg_attr(target_os = "emscripten", ignore)]
+ #[cfg_attr(target_env = "sgx", ignore)] // FIXME: https://github.com/fortanix/rust-sgx/issues/31
+ fn wait_timeout_while_wait() {
+ let m = Arc::new(Mutex::new(()));
+ let c = Arc::new(Condvar::new());
+
+ let g = m.lock().unwrap();
+ let (_g, wait) = c.wait_timeout_while(g, Duration::from_millis(1), |_| true).unwrap();
+ // no spurious wakeups. ensure it timed-out
+ assert!(wait.timed_out());
+ }
- rx.recv().unwrap();
- let g = M.lock().unwrap();
- S.store(2, Ordering::SeqCst);
- C.notify_one();
- drop(g);
+ #[test]
+ #[cfg_attr(target_os = "emscripten", ignore)]
+ fn wait_timeout_while_instant_satisfy() {
+ let m = Arc::new(Mutex::new(()));
+ let c = Arc::new(Condvar::new());
+
+ let g = m.lock().unwrap();
+ let (_g, wait) = c.wait_timeout_while(g, Duration::from_millis(0), |_| false).unwrap();
+ // ensure it didn't time-out even if we were not given any time.
+ assert!(!wait.timed_out());
+ }
- rx.recv().unwrap();
- let _g = M.lock().unwrap();
- S.store(3, Ordering::SeqCst);
- C.notify_one();
+ #[test]
+ #[cfg_attr(target_os = "emscripten", ignore)]
+ #[cfg_attr(target_env = "sgx", ignore)] // FIXME: https://github.com/fortanix/rust-sgx/issues/31
+ fn wait_timeout_while_wake() {
+ let pair = Arc::new((Mutex::new(false), Condvar::new()));
+ let pair_copy = pair.clone();
+
+ let &(ref m, ref c) = &*pair;
+ let g = m.lock().unwrap();
+ let _t = thread::spawn(move || {
+ let &(ref lock, ref cvar) = &*pair_copy;
+ let mut started = lock.lock().unwrap();
+ thread::sleep(Duration::from_millis(1));
+ *started = true;
+ cvar.notify_one();
});
+ let (g2, wait) = c
+ .wait_timeout_while(g, Duration::from_millis(u64::MAX), |&mut notified| !notified)
+ .unwrap();
+ // ensure it didn't time-out even if we were not given any time.
+ assert!(!wait.timed_out());
+ assert!(*g2);
+ }
- let mut state = 0;
- let (_g, success) = C.wait_timeout_with(g, Duration::days(1), |_| {
- assert_eq!(state, S.load(Ordering::SeqCst));
- tx.send(()).unwrap();
- state += 1;
- match state {
- 1|2 => false,
- _ => true,
+ #[test]
+ #[cfg_attr(target_os = "emscripten", ignore)]
+ #[cfg_attr(target_env = "sgx", ignore)] // FIXME: https://github.com/fortanix/rust-sgx/issues/31
+ fn wait_timeout_wake() {
+ let m = Arc::new(Mutex::new(()));
+ let c = Arc::new(Condvar::new());
+
+ loop {
+ let g = m.lock().unwrap();
+
+ let c2 = c.clone();
+ let m2 = m.clone();
+
+ let notified = Arc::new(AtomicBool::new(false));
+ let notified_copy = notified.clone();
+
+ let t = thread::spawn(move || {
+ let _g = m2.lock().unwrap();
+ thread::sleep(Duration::from_millis(1));
+ notified_copy.store(true, Ordering::SeqCst);
+ c2.notify_one();
+ });
+ let (g, timeout_res) = c.wait_timeout(g, Duration::from_millis(u64::MAX)).unwrap();
+ assert!(!timeout_res.timed_out());
+ // spurious wakeups mean this isn't necessarily true
+ // so execute test again, if not notified
+ if !notified.load(Ordering::SeqCst) {
+ t.join().unwrap();
+ continue;
}
- }).unwrap();
- assert!(success);
+ drop(g);
+
+ t.join().unwrap();
+
+ break;
+ }
}
#[test]
#[should_panic]
+ #[cfg_attr(target_os = "emscripten", ignore)]
fn two_mutexes() {
- static M1: StaticMutex = MUTEX_INIT;
- static M2: StaticMutex = MUTEX_INIT;
- static C: StaticCondvar = CONDVAR_INIT;
-
- let mut g = M1.lock().unwrap();
- let _t = thread::spawn(move|| {
- let _g = M1.lock().unwrap();
- C.notify_one();
+ let m = Arc::new(Mutex::new(()));
+ let m2 = m.clone();
+ let c = Arc::new(Condvar::new());
+ let c2 = c.clone();
+
+ let mut g = m.lock().unwrap();
+ let _t = thread::spawn(move || {
+ let _g = m2.lock().unwrap();
+ c2.notify_one();
});
- g = C.wait(g).unwrap();
+ g = c.wait(g).unwrap();
drop(g);
- let _ = C.wait(M2.lock().unwrap()).unwrap();
+ let m = Mutex::new(());
+ let _ = c.wait(m.lock().unwrap()).unwrap();
}
}
projects / rustc.git / blobdiff