library/std/src/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)]
  21 mod tests;
  22
  23 pub mod backtrace;
  24 pub mod fs;
  25 pub mod io;
  26 pub mod lazy_box;
  27 pub mod memchr;
  28 pub mod once;
  29 pub mod process;
  30 pub mod thread;
  31 pub mod thread_info;
  32 pub mod thread_local_dtor;
  33 pub mod thread_parking;
  34 pub mod wstr;
  35 pub mod wtf8;
  36
  37 cfg_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
  45 cfg_if::cfg_if! {
  46     if #[cfg(any(target_os = "l4re",
  47                  feature = "restricted-std",
  48                  all(target_family = "wasm", not(target_os = "emscripten")),
  49                  all(target_vendor = "fortanix", target_env = "sgx")))] {
  50         pub use crate::sys::net;
  51     } else {
  52         pub mod net;
  53     }
  54 }
  55
  56 // common error constructors
  57
  58 /// A trait for viewing representations from std types
  59 #[doc(hidden)]
  60 pub trait AsInner<Inner: ?Sized> {
  61     fn as_inner(&self) -> &Inner;
  62 }
  63
  64 /// A trait for viewing representations from std types
  65 #[doc(hidden)]
  66 pub 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)]
  72 pub trait IntoInner<Inner> {
  73     fn into_inner(self) -> Inner;
  74 }
  75
  76 /// A trait for creating std types from internal representations
  77 #[doc(hidden)]
  78 pub 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
  86 pub fn mul_div_u64(value: u64, numer: u64, denom: u64) -> u64 {
  87     let q = value / denom;
  88     let r = 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 }