From 1b6a04ca5504955c571d1c97504fb45ea0befee4 Mon Sep 17 00:00:00 2001 From: Valentin Popov Date: Mon, 8 Jan 2024 01:21:28 +0400 Subject: Initial vendor packages Signed-off-by: Valentin Popov --- vendor/lazy_static/src/lib.rs | 215 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 215 insertions(+) create mode 100644 vendor/lazy_static/src/lib.rs (limited to 'vendor/lazy_static/src/lib.rs') diff --git a/vendor/lazy_static/src/lib.rs b/vendor/lazy_static/src/lib.rs new file mode 100644 index 0000000..cada0dc --- /dev/null +++ b/vendor/lazy_static/src/lib.rs @@ -0,0 +1,215 @@ +// Copyright 2016 lazy-static.rs Developers +// +// Licensed under the Apache License, Version 2.0, or the MIT license , at your option. This file may not be +// copied, modified, or distributed except according to those terms. + +/*! +A macro for declaring lazily evaluated statics. + +Using this macro, it is possible to have `static`s that require code to be +executed at runtime in order to be initialized. +This includes anything requiring heap allocations, like vectors or hash maps, +as well as anything that requires function calls to be computed. + +# Syntax + +```ignore +lazy_static! { + [pub] static ref NAME_1: TYPE_1 = EXPR_1; + [pub] static ref NAME_2: TYPE_2 = EXPR_2; + ... + [pub] static ref NAME_N: TYPE_N = EXPR_N; +} +``` + +Attributes (including doc comments) are supported as well: + +```rust +# #[macro_use] +# extern crate lazy_static; +# fn main() { +lazy_static! { + /// This is an example for using doc comment attributes + static ref EXAMPLE: u8 = 42; +} +# } +``` + +# Semantics + +For a given `static ref NAME: TYPE = EXPR;`, the macro generates a unique type that +implements `Deref` and stores it in a static with name `NAME`. (Attributes end up +attaching to this type.) + +On first deref, `EXPR` gets evaluated and stored internally, such that all further derefs +can return a reference to the same object. Note that this can lead to deadlocks +if you have multiple lazy statics that depend on each other in their initialization. + +Apart from the lazy initialization, the resulting "static ref" variables +have generally the same properties as regular "static" variables: + +- Any type in them needs to fulfill the `Sync` trait. +- If the type has a destructor, then it will not run when the process exits. + +# Example + +Using the macro: + +```rust +#[macro_use] +extern crate lazy_static; + +use std::collections::HashMap; + +lazy_static! { + static ref HASHMAP: HashMap = { + let mut m = HashMap::new(); + m.insert(0, "foo"); + m.insert(1, "bar"); + m.insert(2, "baz"); + m + }; + static ref COUNT: usize = HASHMAP.len(); + static ref NUMBER: u32 = times_two(21); +} + +fn times_two(n: u32) -> u32 { n * 2 } + +fn main() { + println!("The map has {} entries.", *COUNT); + println!("The entry for `0` is \"{}\".", HASHMAP.get(&0).unwrap()); + println!("A expensive calculation on a static results in: {}.", *NUMBER); +} +``` + +# Implementation details + +The `Deref` implementation uses a hidden static variable that is guarded by an atomic check on each access. + +# Cargo features + +This crate provides one cargo feature: + +- `spin_no_std`: This allows using this crate in a no-std environment, by depending on the standalone `spin` crate. + +*/ + +#![doc(html_root_url = "https://docs.rs/lazy_static/1.4.0")] +#![no_std] + +#[cfg(not(feature = "spin_no_std"))] +#[path="inline_lazy.rs"] +#[doc(hidden)] +pub mod lazy; + +#[cfg(test)] +#[macro_use] +extern crate doc_comment; + +#[cfg(test)] +doctest!("../README.md"); + +#[cfg(feature = "spin_no_std")] +#[path="core_lazy.rs"] +#[doc(hidden)] +pub mod lazy; + +#[doc(hidden)] +pub use core::ops::Deref as __Deref; + +#[macro_export(local_inner_macros)] +#[doc(hidden)] +macro_rules! __lazy_static_internal { + // optional visibility restrictions are wrapped in `()` to allow for + // explicitly passing otherwise implicit information about private items + ($(#[$attr:meta])* ($($vis:tt)*) static ref $N:ident : $T:ty = $e:expr; $($t:tt)*) => { + __lazy_static_internal!(@MAKE TY, $(#[$attr])*, ($($vis)*), $N); + __lazy_static_internal!(@TAIL, $N : $T = $e); + lazy_static!($($t)*); + }; + (@TAIL, $N:ident : $T:ty = $e:expr) => { + impl $crate::__Deref for $N { + type Target = $T; + fn deref(&self) -> &$T { + #[inline(always)] + fn __static_ref_initialize() -> $T { $e } + + #[inline(always)] + fn __stability() -> &'static $T { + __lazy_static_create!(LAZY, $T); + LAZY.get(__static_ref_initialize) + } + __stability() + } + } + impl $crate::LazyStatic for $N { + fn initialize(lazy: &Self) { + let _ = &**lazy; + } + } + }; + // `vis` is wrapped in `()` to prevent parsing ambiguity + (@MAKE TY, $(#[$attr:meta])*, ($($vis:tt)*), $N:ident) => { + #[allow(missing_copy_implementations)] + #[allow(non_camel_case_types)] + #[allow(dead_code)] + $(#[$attr])* + $($vis)* struct $N {__private_field: ()} + #[doc(hidden)] + $($vis)* static $N: $N = $N {__private_field: ()}; + }; + () => () +} + +#[macro_export(local_inner_macros)] +macro_rules! lazy_static { + ($(#[$attr:meta])* static ref $N:ident : $T:ty = $e:expr; $($t:tt)*) => { + // use `()` to explicitly forward the information about private items + __lazy_static_internal!($(#[$attr])* () static ref $N : $T = $e; $($t)*); + }; + ($(#[$attr:meta])* pub static ref $N:ident : $T:ty = $e:expr; $($t:tt)*) => { + __lazy_static_internal!($(#[$attr])* (pub) static ref $N : $T = $e; $($t)*); + }; + ($(#[$attr:meta])* pub ($($vis:tt)+) static ref $N:ident : $T:ty = $e:expr; $($t:tt)*) => { + __lazy_static_internal!($(#[$attr])* (pub ($($vis)+)) static ref $N : $T = $e; $($t)*); + }; + () => () +} + +/// Support trait for enabling a few common operation on lazy static values. +/// +/// This is implemented by each defined lazy static, and +/// used by the free functions in this crate. +pub trait LazyStatic { + #[doc(hidden)] + fn initialize(lazy: &Self); +} + +/// Takes a shared reference to a lazy static and initializes +/// it if it has not been already. +/// +/// This can be used to control the initialization point of a lazy static. +/// +/// Example: +/// +/// ```rust +/// #[macro_use] +/// extern crate lazy_static; +/// +/// lazy_static! { +/// static ref BUFFER: Vec = (0..255).collect(); +/// } +/// +/// fn main() { +/// lazy_static::initialize(&BUFFER); +/// +/// // ... +/// work_with_initialized_data(&BUFFER); +/// } +/// # fn work_with_initialized_data(_: &[u8]) {} +/// ``` +pub fn initialize(lazy: &T) { + LazyStatic::initialize(lazy); +} -- cgit v1.2.3