1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Platform-independent platform abstraction
13 //! This is the platform-independent portion of the standard library's
14 //! platform abstraction layer, whereas `std::sys` is the
15 //! platform-specific portion.
17 //! The relationship between `std::sys_common`, `std::sys` and the
18 //! rest of `std` is complex, with dependencies going in all
19 //! directions: `std` depending on `sys_common`, `sys_common`
20 //! depending on `sys`, and `sys` depending on `sys_common` and `std`.
21 //! Ideally `sys_common` would be split into two and the dependencies
22 //! between them all would form a dag, facilitating the extraction of
23 //! `std::sys` from the standard library.
25 #![allow(missing_docs)]
26 #![allow(missing_debug_implementations)]
32 #[cfg(feature = "backtrace")]
47 #[cfg(target_os = "redox")]
50 #[cfg(not(target_os = "redox"))]
53 #[cfg(feature = "backtrace")]
54 #[cfg(any(all(unix, not(any(target_os = "macos", target_os = "ios", target_os = "emscripten"))),
55 all(windows, target_env = "gnu"),
56 target_os = "redox"))]
59 // common error constructors
61 /// A trait for viewing representations from std types
63 pub trait AsInner<Inner: ?Sized> {
64 fn as_inner(&self) -> &Inner;
67 /// A trait for viewing representations from std types
69 pub trait AsInnerMut<Inner: ?Sized> {
70 fn as_inner_mut(&mut self) -> &mut Inner;
73 /// A trait for extracting representations from std types
75 pub trait IntoInner<Inner> {
76 fn into_inner(self) -> Inner;
79 /// A trait for creating std types from internal representations
81 pub trait FromInner<Inner> {
82 fn from_inner(inner: Inner) -> Self;
85 /// Enqueues a procedure to run when the main thread exits.
87 /// Currently these closures are only run once the main *Rust* thread exits.
88 /// Once the `at_exit` handlers begin running, more may be enqueued, but not
89 /// infinitely so. Eventually a handler registration will be forced to fail.
91 /// Returns `Ok` if the handler was successfully registered, meaning that the
92 /// closure will be run once the main thread exits. Returns `Err` to indicate
93 /// that the closure could not be registered, meaning that it is not scheduled
95 pub fn at_exit<F: FnOnce() + Send + 'static>(f: F) -> Result<(), ()> {
96 if at_exit_imp::push(Box::new(f)) {Ok(())} else {Err(())}
99 macro_rules! rtabort {
100 ($($t:tt)*) => (::sys_common::util::abort(format_args!($($t)*)))
103 /// One-time runtime cleanup.
105 static CLEANUP: Once = Once::new();
106 CLEANUP.call_once(|| unsafe {
107 sys::args::cleanup();
108 sys::stack_overflow::cleanup();
109 at_exit_imp::cleanup();
113 // Computes (value*numer)/denom without overflow, as long as both
114 // (numer*denom) and the overall result fit into i64 (which is the case
115 // for our time conversions).
116 #[allow(dead_code)] // not used on all platforms
117 pub fn mul_div_u64(value: u64, numer: u64, denom: u64) -> u64 {
118 let q = value / denom;
119 let r = value % denom;
120 // Decompose value as (value/denom*denom + value%denom),
121 // substitute into (value*numer)/denom and simplify.
122 // r < denom, so (denom*numer) is the upper bound of (r*numer)
123 q * numer + r * numer / denom
128 assert_eq!(mul_div_u64( 1_000_000_000_001, 1_000_000_000, 1_000_000),
129 1_000_000_000_001_000);