1 //! Platform-independent platform abstraction
3 //! This is the platform-independent portion of the standard library's
4 //! platform abstraction layer, whereas `std::sys` is the
5 //! platform-specific portion.
7 //! The relationship between `std::sys_common`, `std::sys` and the
8 //! rest of `std` is complex, with dependencies going in all
9 //! directions: `std` depending on `sys_common`, `sys_common`
10 //! depending on `sys`, and `sys` depending on `sys_common` and `std`.
11 //! Ideally `sys_common` would be split into two and the dependencies
12 //! between them all would form a dag, facilitating the extraction of
13 //! `std::sys` from the standard library.
15 #![allow(missing_docs)]
16 #![allow(missing_debug_implementations)]
18 use crate::sync::Once;
21 macro_rules! rtabort {
22 ($($t:tt)*) => (crate::sys_common::util::abort(format_args!($($t)*)))
25 macro_rules! rtassert {
26 ($e:expr) => (if !$e {
27 rtabort!(concat!("assertion failed: ", stringify!($e)));
33 #[cfg(feature = "backtrace")]
50 if #[cfg(any(target_os = "cloudabi",
53 all(target_arch = "wasm32", not(target_os = "emscripten")),
54 all(target_vendor = "fortanix", target_env = "sgx")))] {
55 pub use crate::sys::net;
61 #[cfg(feature = "backtrace")]
62 #[cfg(any(all(unix, not(target_os = "emscripten")),
63 all(windows, target_env = "gnu"),
64 target_os = "redox"))]
67 // common error constructors
69 /// A trait for viewing representations from std types
71 pub trait AsInner<Inner: ?Sized> {
72 fn as_inner(&self) -> &Inner;
75 /// A trait for viewing representations from std types
77 pub trait AsInnerMut<Inner: ?Sized> {
78 fn as_inner_mut(&mut self) -> &mut Inner;
81 /// A trait for extracting representations from std types
83 pub trait IntoInner<Inner> {
84 fn into_inner(self) -> Inner;
87 /// A trait for creating std types from internal representations
89 pub trait FromInner<Inner> {
90 fn from_inner(inner: Inner) -> Self;
93 /// Enqueues a procedure to run when the main thread exits.
95 /// Currently these closures are only run once the main *Rust* thread exits.
96 /// Once the `at_exit` handlers begin running, more may be enqueued, but not
97 /// infinitely so. Eventually a handler registration will be forced to fail.
99 /// Returns `Ok` if the handler was successfully registered, meaning that the
100 /// closure will be run once the main thread exits. Returns `Err` to indicate
101 /// that the closure could not be registered, meaning that it is not scheduled
103 pub fn at_exit<F: FnOnce() + Send + 'static>(f: F) -> Result<(), ()> {
104 if at_exit_imp::push(Box::new(f)) {Ok(())} else {Err(())}
107 /// One-time runtime cleanup.
109 static CLEANUP: Once = Once::new();
110 CLEANUP.call_once(|| unsafe {
111 sys::args::cleanup();
112 sys::stack_overflow::cleanup();
113 at_exit_imp::cleanup();
117 // Computes (value*numer)/denom without overflow, as long as both
118 // (numer*denom) and the overall result fit into i64 (which is the case
119 // for our time conversions).
120 #[allow(dead_code)] // not used on all platforms
121 pub fn mul_div_u64(value: u64, numer: u64, denom: u64) -> u64 {
122 let q = value / denom;
123 let r = value % denom;
124 // Decompose value as (value/denom*denom + value%denom),
125 // substitute into (value*numer)/denom and simplify.
126 // r < denom, so (denom*numer) is the upper bound of (r*numer)
127 q * numer + r * numer / denom
132 assert_eq!(mul_div_u64( 1_000_000_000_001, 1_000_000_000, 1_000_000),
133 1_000_000_000_001_000);