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Diffstat (limited to 'vendor/spin/src/lib.rs')
| -rw-r--r-- | vendor/spin/src/lib.rs | 221 |
1 files changed, 0 insertions, 221 deletions
diff --git a/vendor/spin/src/lib.rs b/vendor/spin/src/lib.rs deleted file mode 100644 index 50768bc..0000000 --- a/vendor/spin/src/lib.rs +++ /dev/null @@ -1,221 +0,0 @@ -#![cfg_attr(all(not(feature = "std"), not(test)), no_std)] -#![cfg_attr(docsrs, feature(doc_cfg))] -#![deny(missing_docs)] - -//! This crate provides [spin-based](https://en.wikipedia.org/wiki/Spinlock) versions of the -//! primitives in `std::sync` and `std::lazy`. Because synchronization is done through spinning, -//! the primitives are suitable for use in `no_std` environments. -//! -//! # Features -//! -//! - `Mutex`, `RwLock`, `Once`/`SyncOnceCell`, and `SyncLazy` equivalents -//! -//! - Support for `no_std` environments -//! -//! - [`lock_api`](https://crates.io/crates/lock_api) compatibility -//! -//! - Upgradeable `RwLock` guards -//! -//! - Guards can be sent and shared between threads -//! -//! - Guard leaking -//! -//! - Ticket locks -//! -//! - Different strategies for dealing with contention -//! -//! # Relationship with `std::sync` -//! -//! While `spin` is not a drop-in replacement for `std::sync` (and -//! [should not be considered as such](https://matklad.github.io/2020/01/02/spinlocks-considered-harmful.html)) -//! an effort is made to keep this crate reasonably consistent with `std::sync`. -//! -//! Many of the types defined in this crate have 'additional capabilities' when compared to `std::sync`: -//! -//! - Because spinning does not depend on the thread-driven model of `std::sync`, guards ([`MutexGuard`], -//! [`RwLockReadGuard`], [`RwLockWriteGuard`], etc.) may be sent and shared between threads. -//! -//! - [`RwLockUpgradableGuard`] supports being upgraded into a [`RwLockWriteGuard`]. -//! -//! - Guards support [leaking](https://doc.rust-lang.org/nomicon/leaking.html). -//! -//! - [`Once`] owns the value returned by its `call_once` initializer. -//! -//! - [`RwLock`] supports counting readers and writers. -//! -//! Conversely, the types in this crate do not have some of the features `std::sync` has: -//! -//! - Locks do not track [panic poisoning](https://doc.rust-lang.org/nomicon/poisoning.html). -//! -//! ## Feature flags -//! -//! The crate comes with a few feature flags that you may wish to use. -//! -//! - `lock_api` enables support for [`lock_api`](https://crates.io/crates/lock_api) -//! -//! - `ticket_mutex` uses a ticket lock for the implementation of `Mutex` -//! -//! - `fair_mutex` enables a fairer implementation of `Mutex` that uses eventual fairness to avoid -//! starvation -//! -//! - `std` enables support for thread yielding instead of spinning - -#[cfg(any(test, feature = "std"))] -extern crate core; - -#[cfg(feature = "portable_atomic")] -extern crate portable_atomic; - -#[cfg(not(feature = "portable_atomic"))] -use core::sync::atomic; -#[cfg(feature = "portable_atomic")] -use portable_atomic as atomic; - -#[cfg(feature = "barrier")] -#[cfg_attr(docsrs, doc(cfg(feature = "barrier")))] -pub mod barrier; -#[cfg(feature = "lazy")] -#[cfg_attr(docsrs, doc(cfg(feature = "lazy")))] -pub mod lazy; -#[cfg(feature = "mutex")] -#[cfg_attr(docsrs, doc(cfg(feature = "mutex")))] -pub mod mutex; -#[cfg(feature = "once")] -#[cfg_attr(docsrs, doc(cfg(feature = "once")))] -pub mod once; -pub mod relax; -#[cfg(feature = "rwlock")] -#[cfg_attr(docsrs, doc(cfg(feature = "rwlock")))] -pub mod rwlock; - -#[cfg(feature = "mutex")] -#[cfg_attr(docsrs, doc(cfg(feature = "mutex")))] -pub use mutex::MutexGuard; -#[cfg(feature = "std")] -#[cfg_attr(docsrs, doc(cfg(feature = "std")))] -pub use relax::Yield; -pub use relax::{RelaxStrategy, Spin}; -#[cfg(feature = "rwlock")] -#[cfg_attr(docsrs, doc(cfg(feature = "rwlock")))] -pub use rwlock::RwLockReadGuard; - -// Avoid confusing inference errors by aliasing away the relax strategy parameter. Users that need to use a different -// relax strategy can do so by accessing the types through their fully-qualified path. This is a little bit horrible -// but sadly adding a default type parameter is *still* a breaking change in Rust (for understandable reasons). - -/// A primitive that synchronizes the execution of multiple threads. See [`barrier::Barrier`] for documentation. -/// -/// A note for advanced users: this alias exists to avoid subtle type inference errors due to the default relax -/// strategy type parameter. If you need a non-default relax strategy, use the fully-qualified path. -#[cfg(feature = "barrier")] -#[cfg_attr(docsrs, doc(cfg(feature = "barrier")))] -pub type Barrier = crate::barrier::Barrier; - -/// A value which is initialized on the first access. See [`lazy::Lazy`] for documentation. -/// -/// A note for advanced users: this alias exists to avoid subtle type inference errors due to the default relax -/// strategy type parameter. If you need a non-default relax strategy, use the fully-qualified path. -#[cfg(feature = "lazy")] -#[cfg_attr(docsrs, doc(cfg(feature = "lazy")))] -pub type Lazy<T, F = fn() -> T> = crate::lazy::Lazy<T, F>; - -/// A primitive that synchronizes the execution of multiple threads. See [`mutex::Mutex`] for documentation. -/// -/// A note for advanced users: this alias exists to avoid subtle type inference errors due to the default relax -/// strategy type parameter. If you need a non-default relax strategy, use the fully-qualified path. -#[cfg(feature = "mutex")] -#[cfg_attr(docsrs, doc(cfg(feature = "mutex")))] -pub type Mutex<T> = crate::mutex::Mutex<T>; - -/// A primitive that provides lazy one-time initialization. See [`once::Once`] for documentation. -/// -/// A note for advanced users: this alias exists to avoid subtle type inference errors due to the default relax -/// strategy type parameter. If you need a non-default relax strategy, use the fully-qualified path. -#[cfg(feature = "once")] -#[cfg_attr(docsrs, doc(cfg(feature = "once")))] -pub type Once<T = ()> = crate::once::Once<T>; - -/// A lock that provides data access to either one writer or many readers. See [`rwlock::RwLock`] for documentation. -/// -/// A note for advanced users: this alias exists to avoid subtle type inference errors due to the default relax -/// strategy type parameter. If you need a non-default relax strategy, use the fully-qualified path. -#[cfg(feature = "rwlock")] -#[cfg_attr(docsrs, doc(cfg(feature = "rwlock")))] -pub type RwLock<T> = crate::rwlock::RwLock<T>; - -/// A guard that provides immutable data access but can be upgraded to [`RwLockWriteGuard`]. See -/// [`rwlock::RwLockUpgradableGuard`] for documentation. -/// -/// A note for advanced users: this alias exists to avoid subtle type inference errors due to the default relax -/// strategy type parameter. If you need a non-default relax strategy, use the fully-qualified path. -#[cfg(feature = "rwlock")] -#[cfg_attr(docsrs, doc(cfg(feature = "rwlock")))] -pub type RwLockUpgradableGuard<'a, T> = crate::rwlock::RwLockUpgradableGuard<'a, T>; - -/// A guard that provides mutable data access. See [`rwlock::RwLockWriteGuard`] for documentation. -/// -/// A note for advanced users: this alias exists to avoid subtle type inference errors due to the default relax -/// strategy type parameter. If you need a non-default relax strategy, use the fully-qualified path. -#[cfg(feature = "rwlock")] -#[cfg_attr(docsrs, doc(cfg(feature = "rwlock")))] -pub type RwLockWriteGuard<'a, T> = crate::rwlock::RwLockWriteGuard<'a, T>; - -/// Spin synchronisation primitives, but compatible with [`lock_api`](https://crates.io/crates/lock_api). -#[cfg(feature = "lock_api")] -#[cfg_attr(docsrs, doc(cfg(feature = "lock_api")))] -pub mod lock_api { - /// A lock that provides mutually exclusive data access (compatible with [`lock_api`](https://crates.io/crates/lock_api)). - #[cfg(feature = "mutex")] - #[cfg_attr(docsrs, doc(cfg(feature = "mutex")))] - pub type Mutex<T> = lock_api_crate::Mutex<crate::Mutex<()>, T>; - - /// A guard that provides mutable data access (compatible with [`lock_api`](https://crates.io/crates/lock_api)). - #[cfg(feature = "mutex")] - #[cfg_attr(docsrs, doc(cfg(feature = "mutex")))] - pub type MutexGuard<'a, T> = lock_api_crate::MutexGuard<'a, crate::Mutex<()>, T>; - - /// A lock that provides data access to either one writer or many readers (compatible with [`lock_api`](https://crates.io/crates/lock_api)). - #[cfg(feature = "rwlock")] - #[cfg_attr(docsrs, doc(cfg(feature = "rwlock")))] - pub type RwLock<T> = lock_api_crate::RwLock<crate::RwLock<()>, T>; - - /// A guard that provides immutable data access (compatible with [`lock_api`](https://crates.io/crates/lock_api)). - #[cfg(feature = "rwlock")] - #[cfg_attr(docsrs, doc(cfg(feature = "rwlock")))] - pub type RwLockReadGuard<'a, T> = lock_api_crate::RwLockReadGuard<'a, crate::RwLock<()>, T>; - - /// A guard that provides mutable data access (compatible with [`lock_api`](https://crates.io/crates/lock_api)). - #[cfg(feature = "rwlock")] - #[cfg_attr(docsrs, doc(cfg(feature = "rwlock")))] - pub type RwLockWriteGuard<'a, T> = lock_api_crate::RwLockWriteGuard<'a, crate::RwLock<()>, T>; - - /// A guard that provides immutable data access but can be upgraded to [`RwLockWriteGuard`] (compatible with [`lock_api`](https://crates.io/crates/lock_api)). - #[cfg(feature = "rwlock")] - #[cfg_attr(docsrs, doc(cfg(feature = "rwlock")))] - pub type RwLockUpgradableReadGuard<'a, T> = - lock_api_crate::RwLockUpgradableReadGuard<'a, crate::RwLock<()>, T>; -} - -/// In the event of an invalid operation, it's best to abort the current process. -#[cfg(feature = "fair_mutex")] -fn abort() -> ! { - #[cfg(not(feature = "std"))] - { - // Panicking while panicking is defined by Rust to result in an abort. - struct Panic; - - impl Drop for Panic { - fn drop(&mut self) { - panic!("aborting due to invalid operation"); - } - } - - let _panic = Panic; - panic!("aborting due to invalid operation"); - } - - #[cfg(feature = "std")] - { - std::process::abort(); - } -} |