diff options
| author | Fenrir <[email protected]> | 2018-01-21 14:06:28 -0700 |
|---|---|---|
| committer | FenrirWolf <[email protected]> | 2018-01-21 19:16:33 -0700 |
| commit | 23be3f4885688e5e0011005e2295c75168854c0a (patch) | |
| tree | dd0850f9c73c489e114a761d5c0757f3dbec3a65 /ctr-std/src/sync/once.rs | |
| parent | Update CI for Rust nightly-2017-12-01 + other fixes (diff) | |
| download | archived-ctru-rs-23be3f4885688e5e0011005e2295c75168854c0a.tar.xz archived-ctru-rs-23be3f4885688e5e0011005e2295c75168854c0a.zip | |
Recreate ctr-std from latest nightly
Diffstat (limited to 'ctr-std/src/sync/once.rs')
| -rw-r--r-- | ctr-std/src/sync/once.rs | 117 |
1 files changed, 103 insertions, 14 deletions
diff --git a/ctr-std/src/sync/once.rs b/ctr-std/src/sync/once.rs index c449315..6fd8b6a 100644 --- a/ctr-std/src/sync/once.rs +++ b/ctr-std/src/sync/once.rs @@ -72,9 +72,11 @@ use thread::{self, Thread}; /// A synchronization primitive which can be used to run a one-time global /// initialization. Useful for one-time initialization for FFI or related -/// functionality. This type can only be constructed with the `ONCE_INIT` +/// functionality. This type can only be constructed with the [`ONCE_INIT`] /// value. /// +/// [`ONCE_INIT`]: constant.ONCE_INIT.html +/// /// # Examples /// /// ``` @@ -101,15 +103,28 @@ unsafe impl Sync for Once {} #[stable(feature = "rust1", since = "1.0.0")] unsafe impl Send for Once {} -/// State yielded to the `call_once_force` method which can be used to query -/// whether the `Once` was previously poisoned or not. +/// State yielded to [`call_once_force`]’s closure parameter. The state can be +/// used to query the poison status of the [`Once`]. +/// +/// [`call_once_force`]: struct.Once.html#method.call_once_force +/// [`Once`]: struct.Once.html #[unstable(feature = "once_poison", issue = "33577")] #[derive(Debug)] pub struct OnceState { poisoned: bool, } -/// Initialization value for static `Once` values. +/// Initialization value for static [`Once`] values. +/// +/// [`Once`]: struct.Once.html +/// +/// # Examples +/// +/// ``` +/// use std::sync::{Once, ONCE_INIT}; +/// +/// static START: Once = ONCE_INIT; +/// ``` #[stable(feature = "rust1", since = "1.0.0")] pub const ONCE_INIT: Once = Once::new(); @@ -212,15 +227,52 @@ impl Once { self.call_inner(false, &mut |_| f.take().unwrap()()); } - /// Performs the same function as `call_once` except ignores poisoning. + /// Performs the same function as [`call_once`] except ignores poisoning. + /// + /// Unlike [`call_once`], if this `Once` has been poisoned (i.e. a previous + /// call to `call_once` or `call_once_force` caused a panic), calling + /// `call_once_force` will still invoke the closure `f` and will _not_ + /// result in an immediate panic. If `f` panics, the `Once` will remain + /// in a poison state. If `f` does _not_ panic, the `Once` will no + /// longer be in a poison state and all future calls to `call_once` or + /// `call_one_force` will no-op. + /// + /// The closure `f` is yielded a [`OnceState`] structure which can be used + /// to query the poison status of the `Once`. + /// + /// [`call_once`]: struct.Once.html#method.call_once + /// [`OnceState`]: struct.OnceState.html + /// + /// # Examples + /// + /// ``` + /// #![feature(once_poison)] + /// + /// use std::sync::{Once, ONCE_INIT}; + /// use std::thread; + /// + /// static INIT: Once = ONCE_INIT; + /// + /// // poison the once + /// let handle = thread::spawn(|| { + /// INIT.call_once(|| panic!()); + /// }); + /// assert!(handle.join().is_err()); /// - /// If this `Once` has been poisoned (some initialization panicked) then - /// this function will continue to attempt to call initialization functions - /// until one of them doesn't panic. + /// // poisoning propagates + /// let handle = thread::spawn(|| { + /// INIT.call_once(|| {}); + /// }); + /// assert!(handle.join().is_err()); /// - /// The closure `f` is yielded a structure which can be used to query the - /// state of this `Once` (whether initialization has previously panicked or - /// not). + /// // call_once_force will still run and reset the poisoned state + /// INIT.call_once_force(|state| { + /// assert!(state.poisoned()); + /// }); + /// + /// // once any success happens, we stop propagating the poison + /// INIT.call_once(|| {}); + /// ``` #[unstable(feature = "once_poison", issue = "33577")] pub fn call_once_force<F>(&'static self, f: F) where F: FnOnce(&OnceState) { // same as above, just with a different parameter to `call_inner`. @@ -366,10 +418,47 @@ impl Drop for Finish { } impl OnceState { - /// Returns whether the associated `Once` has been poisoned. + /// Returns whether the associated [`Once`] was poisoned prior to the + /// invocation of the closure passed to [`call_once_force`]. + /// + /// [`call_once_force`]: struct.Once.html#method.call_once_force + /// [`Once`]: struct.Once.html + /// + /// # Examples + /// + /// A poisoned `Once`: + /// + /// ``` + /// #![feature(once_poison)] + /// + /// use std::sync::{Once, ONCE_INIT}; + /// use std::thread; + /// + /// static INIT: Once = ONCE_INIT; + /// + /// // poison the once + /// let handle = thread::spawn(|| { + /// INIT.call_once(|| panic!()); + /// }); + /// assert!(handle.join().is_err()); + /// + /// INIT.call_once_force(|state| { + /// assert!(state.poisoned()); + /// }); + /// ``` + /// + /// An unpoisoned `Once`: + /// + /// ``` + /// #![feature(once_poison)] + /// + /// use std::sync::{Once, ONCE_INIT}; + /// + /// static INIT: Once = ONCE_INIT; /// - /// Once an initalization routine for a `Once` has panicked it will forever - /// indicate to future forced initialization routines that it is poisoned. + /// INIT.call_once_force(|state| { + /// assert!(!state.poisoned()); + /// }); #[unstable(feature = "once_poison", issue = "33577")] pub fn poisoned(&self) -> bool { self.poisoned |