1//! Platform-independent platform abstraction
2//!
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.
6//!
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//! This is because `sys_common` not only contains platform-independent code,
12//! but also code that is shared between the different platforms in `sys`.
13//! Ideally all that shared code should be moved to `sys::common`,
14//! and the dependencies between `std`, `sys_common` and `sys` all would form a dag.
15//! Progress on this is tracked in #84187.
16
17#![allow(missing_docs)]
18#![allow(missing_debug_implementations)]
19
20#[cfg(test)]
21mod tests;
22
23pub mod backtrace;
24pub mod fs;
25pub mod io;
26pub mod lazy_box;
27pub mod memchr;
28pub mod once;
29pub mod process;
30pub mod thread;
31pub mod thread_info;
32pub mod thread_local_dtor;
33pub mod thread_parking;
34pub mod wstr;
35pub mod wtf8;
36
37cfg_if::cfg_if! {
38 if #[cfg(target_os = "windows")] {
39 pub use crate::sys::thread_local_key;
40 } else {
41 pub mod thread_local_key;
42 }
43}
44
45cfg_if::cfg_if! {
46 if #[cfg(any(
47 all(unix, not(target_os = "l4re")),
48 windows,
49 target_os = "hermit",
50 target_os = "solid_asp3"
51 ))] {
52 pub mod net;
53 } else {
54 pub use crate::sys::net;
55 }
56}
57
58// common error constructors
59
60/// A trait for viewing representations from std types
61#[doc(hidden)]
62pub trait AsInner<Inner: ?Sized> {
63 fn as_inner(&self) -> &Inner;
64}
65
66/// A trait for viewing representations from std types
67#[doc(hidden)]
68pub trait AsInnerMut<Inner: ?Sized> {
69 fn as_inner_mut(&mut self) -> &mut Inner;
70}
71
72/// A trait for extracting representations from std types
73#[doc(hidden)]
74pub trait IntoInner<Inner> {
75 fn into_inner(self) -> Inner;
76}
77
78/// A trait for creating std types from internal representations
79#[doc(hidden)]
80pub trait FromInner<Inner> {
81 fn from_inner(inner: Inner) -> Self;
82}
83
84// Computes (value*numer)/denom without overflow, as long as both
85// (numer*denom) and the overall result fit into i64 (which is the case
86// for our time conversions).
87#[allow(dead_code)] // not used on all platforms
88pub fn mul_div_u64(value: u64, numer: u64, denom: u64) -> u64 {
89 let q: u64 = value / denom;
90 let r: u64 = value % denom;
91 // Decompose value as (value/denom*denom + value%denom),
92 // substitute into (value*numer)/denom and simplify.
93 // r < denom, so (denom*numer) is the upper bound of (r*numer)
94 q * numer + r * numer / denom
95}
96