std/sys_common/
mod.rs

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

std/sys_common/
mod.rs
