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)]
21 use crate::sync::Once;
24 macro_rules! rtabort {
25 ($($t:tt)*) => (crate::sys_common::util::abort(format_args!($($t)*)))
28 macro_rules! rtassert {
31 rtabort!(concat!("assertion failed: ", stringify!($e)));
36 #[allow(unused_macros)] // not used on all platforms
37 macro_rules! rtunwrap {
38 ($ok:ident, $e:expr) => {
42 let err = err.as_ref().map(drop); // map Ok/Some which might not be Debug
43 rtabort!(concat!("unwrap failed: ", stringify!($e), " = {:?}"), err)
57 // `doc` is required because `sys/mod.rs` imports `unix/ext/mod.rs` on Windows
58 // when generating documentation.
59 #[cfg(any(doc, not(windows)))]
67 pub mod thread_local_dtor;
68 pub mod thread_local_key;
69 pub mod thread_parker;
74 if #[cfg(any(target_os = "l4re",
76 feature = "restricted-std",
77 all(target_arch = "wasm32", not(target_os = "emscripten")),
78 all(target_vendor = "fortanix", target_env = "sgx")))] {
79 pub use crate::sys::net;
85 // common error constructors
87 /// A trait for viewing representations from std types
89 pub trait AsInner<Inner: ?Sized> {
90 fn as_inner(&self) -> &Inner;
93 /// A trait for viewing representations from std types
95 pub trait AsInnerMut<Inner: ?Sized> {
96 fn as_inner_mut(&mut self) -> &mut Inner;
99 /// A trait for extracting representations from std types
101 pub trait IntoInner<Inner> {
102 fn into_inner(self) -> Inner;
105 /// A trait for creating std types from internal representations
107 pub trait FromInner<Inner> {
108 fn from_inner(inner: Inner) -> Self;
111 /// Enqueues a procedure to run when the main thread exits.
113 /// Currently these closures are only run once the main *Rust* thread exits.
114 /// Once the `at_exit` handlers begin running, more may be enqueued, but not
115 /// infinitely so. Eventually a handler registration will be forced to fail.
117 /// Returns `Ok` if the handler was successfully registered, meaning that the
118 /// closure will be run once the main thread exits. Returns `Err` to indicate
119 /// that the closure could not be registered, meaning that it is not scheduled
121 pub fn at_exit<F: FnOnce() + Send + 'static>(f: F) -> Result<(), ()> {
122 if at_exit_imp::push(Box::new(f)) { Ok(()) } else { Err(()) }
125 /// One-time runtime cleanup.
127 static CLEANUP: Once = Once::new();
128 CLEANUP.call_once(|| unsafe {
129 sys::args::cleanup();
130 sys::stack_overflow::cleanup();
131 at_exit_imp::cleanup();
135 // Computes (value*numer)/denom without overflow, as long as both
136 // (numer*denom) and the overall result fit into i64 (which is the case
137 // for our time conversions).
138 #[allow(dead_code)] // not used on all platforms
139 pub fn mul_div_u64(value: u64, numer: u64, denom: u64) -> u64 {
140 let q = value / denom;
141 let r = value % denom;
142 // Decompose value as (value/denom*denom + value%denom),
143 // substitute into (value*numer)/denom and simplify.
144 // r < denom, so (denom*numer) is the upper bound of (r*numer)
145 q * numer + r * numer / denom