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 wstr;
24pub mod wtf8;
25
26// common error constructors
27
28/// A trait for viewing representations from std types
29#[doc(hidden)]
30#[allow(dead_code)] // not used on all platforms
31pub trait AsInner<Inner: ?Sized> {
32 fn as_inner(&self) -> &Inner;
33}
34
35/// A trait for viewing representations from std types
36#[doc(hidden)]
37#[allow(dead_code)] // not used on all platforms
38pub trait AsInnerMut<Inner: ?Sized> {
39 fn as_inner_mut(&mut self) -> &mut Inner;
40}
41
42/// A trait for extracting representations from std types
43#[doc(hidden)]
44pub trait IntoInner<Inner> {
45 fn into_inner(self) -> Inner;
46}
47
48/// A trait for creating std types from internal representations
49#[doc(hidden)]
50pub trait FromInner<Inner> {
51 fn from_inner(inner: Inner) -> Self;
52}
53
54// Computes (value*numer)/denom without overflow, as long as both
55// (numer*denom) and the overall result fit into i64 (which is the case
56// for our time conversions).
57#[allow(dead_code)] // not used on all platforms
58pub fn mul_div_u64(value: u64, numer: u64, denom: u64) -> u64 {
59 let q: u64 = value / denom;
60 let r: u64 = value % denom;
61 // Decompose value as (value/denom*denom + value%denom),
62 // substitute into (value*numer)/denom and simplify.
63 // r < denom, so (denom*numer) is the upper bound of (r*numer)
64 q * numer + r * numer / denom
65}
66
67pub fn ignore_notfound<T>(result: crate::io::Result<T>) -> crate::io::Result<()> {
68 match result {
69 Err(err: Error) if err.kind() == crate::io::ErrorKind::NotFound => Ok(()),
70 Ok(_) => Ok(()),
71 Err(err: Error) => Err(err),
72 }
73}
74