Crate conquer_once
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This crate provides a set of synchronized initialization primitives, which are primarily useful for lazy and one-time initialization of static variables.
All types exported through the noblock and spin modules are fully
#[no_std] compatible.
Synchronization Primitives
With the std cargo feature enabled (which is the default setting), this
crate provides the [Once], [OnceCell] and [Lazy] types and the
equivalents of these types using spin-locks in the spin sub-module.
Lazy
The [Lazy] type has the same functionality as the lazy_static! macro,
but works without any macros.
Once
This type is very similar to the std::sync::Once type in the standard
library, but features a richer API.
OnceCell
A cell type with interior mutability that can be only written to once and only allows read access to the contained data after initialization.
Credits
Inspiration for this crate is heavily drawn from
once_cell,
but features clear distinctions between blocking and non-blocking operations
and support for #[no_std] environments out of the box, by offering
additional synchronization primitives using spin-locks instead of OS reliant
blocking mechanisms.
Unlike many other crates, support for the #[no_std] compatible types is
not mutually exclusive with using the types relying on the presence of the
standard library.
The idea for the implementation of the [Once]/[OnceCell] types is also
directly inspired by the implementation in the standard library.
The reasoning behind re-implementing [Once] is the fairly restricted and
partly unstable API of the version in the standard library.
Modules
Re-exports of internal generic type for the purpose of accessing their documentation.
Synchronized one-time and lazy initialization primitives that permit only non-blocking synchronized initialization operations.
Synchronized one-time and lazy initialization primitives that use spin-locks in case of concurrent accesses under contention.
Enums
Possible error variants of non-blocking fallible get calls.
Possible error variants of non-blocking initialization calls.