Vendor things

third-party/vendor/crossbeam/src/lib.rs

@@ -0,0 +1,81 @@
+//! Tools for concurrent programming.
+//!
+//! ## Atomics
+//!
+//! * [`AtomicCell`], a thread-safe mutable memory location.
+//! * [`AtomicConsume`], for reading from primitive atomic types with "consume" ordering.
+//!
+//! ## Data structures
+//!
+//! * [`deque`], work-stealing deques for building task schedulers.
+//! * [`ArrayQueue`], a bounded MPMC queue that allocates a fixed-capacity buffer on construction.
+//! * [`SegQueue`], an unbounded MPMC queue that allocates small buffers, segments, on demand.
+//!
+//! ## Memory management
+//!
+//! * [`epoch`], an epoch-based garbage collector.
+//!
+//! ## Thread synchronization
+//!
+//! * [`channel`], multi-producer multi-consumer channels for message passing.
+//! * [`Parker`], a thread parking primitive.
+//! * [`ShardedLock`], a sharded reader-writer lock with fast concurrent reads.
+//! * [`WaitGroup`], for synchronizing the beginning or end of some computation.
+//!
+//! ## Utilities
+//!
+//! * [`Backoff`], for exponential backoff in spin loops.
+//! * [`CachePadded`], for padding and aligning a value to the length of a cache line.
+//! * [`scope`], for spawning threads that borrow local variables from the stack.
+//!
+//! [`AtomicCell`]: atomic::AtomicCell
+//! [`AtomicConsume`]: atomic::AtomicConsume
+//! [`ArrayQueue`]: queue::ArrayQueue
+//! [`SegQueue`]: queue::SegQueue
+//! [`Parker`]: sync::Parker
+//! [`ShardedLock`]: sync::ShardedLock
+//! [`WaitGroup`]: sync::WaitGroup
+//! [`Backoff`]: utils::Backoff
+//! [`CachePadded`]: utils::CachePadded
+
+#![doc(test(
+    no_crate_inject,
+    attr(
+        deny(warnings, rust_2018_idioms),
+        allow(dead_code, unused_assignments, unused_variables)
+    )
+))]
+#![warn(
+    missing_docs,
+    missing_debug_implementations,
+    rust_2018_idioms,
+    unreachable_pub
+)]
+#![cfg_attr(not(feature = "std"), no_std)]
+
+pub use crossbeam_utils::atomic;
+
+pub mod utils {
+    //! Miscellaneous utilities.
+    //!
+    //! * [`Backoff`], for exponential backoff in spin loops.
+    //! * [`CachePadded`], for padding and aligning a value to the length of a cache line.
+
+    pub use crossbeam_utils::Backoff;
+    pub use crossbeam_utils::CachePadded;
+}
+
+#[cfg(feature = "alloc")]
+#[doc(inline)]
+pub use {crossbeam_epoch as epoch, crossbeam_queue as queue};
+
+#[cfg(feature = "std")]
+#[doc(inline)]
+pub use {
+    crossbeam_channel as channel, crossbeam_channel::select, crossbeam_deque as deque,
+    crossbeam_utils::sync,
+};
+
+#[cfg(feature = "std")]
+#[cfg(not(crossbeam_loom))]
+pub use crossbeam_utils::thread::{self, scope};