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 process;
28pub mod thread_local_dtor;
29pub mod thread_parking;
30pub mod wstr;
31pub mod wtf8;
32
33cfg_if::cfg_if! {
34 if #[cfg(target_os = "windows")] {
35 pub use crate::sys::thread_local_key;
36 } else {
37 pub mod thread_local_key;
38 }
39}
40
41cfg_if::cfg_if! {
42 if #[cfg(any(
43 all(unix, not(target_os = "l4re")),
44 windows,
45 target_os = "hermit",
46 target_os = "solid_asp3"
47 ))] {
48 pub mod net;
49 } else {
50 pub use crate::sys::net;
51 }
52}
53
54// common error constructors
55
56/// A trait for viewing representations from std types
57#[doc(hidden)]
58#[allow(dead_code)] // not used on all platforms
59pub trait AsInner<Inner: ?Sized> {
60 fn as_inner(&self) -> &Inner;
61}
62
63/// A trait for viewing representations from std types
64#[doc(hidden)]
65#[allow(dead_code)] // not used on all platforms
66pub trait AsInnerMut<Inner: ?Sized> {
67 fn as_inner_mut(&mut self) -> &mut Inner;
68}
69
70/// A trait for extracting representations from std types
71#[doc(hidden)]
72pub trait IntoInner<Inner> {
73 fn into_inner(self) -> Inner;
74}
75
76/// A trait for creating std types from internal representations
77#[doc(hidden)]
78pub trait FromInner<Inner> {
79 fn from_inner(inner: Inner) -> Self;
80}
81
82// Computes (value*numer)/denom without overflow, as long as both
83// (numer*denom) and the overall result fit into i64 (which is the case
84// for our time conversions).
85#[allow(dead_code)] // not used on all platforms
86pub fn mul_div_u64(value: u64, numer: u64, denom: u64) -> u64 {
87 let q: u64 = value / denom;
88 let r: u64 = value % denom;
89 // Decompose value as (value/denom*denom + value%denom),
90 // substitute into (value*numer)/denom and simplify.
91 // r < denom, so (denom*numer) is the upper bound of (r*numer)
92 q * numer + r * numer / denom
93}
94