1 files changed, 89 insertions, 0 deletions
diff --git a/library/std/src/sys_common/mod.rs b/library/std/src/sys_common/mod.rs
new file mode 100644
index 000000000..80f56bf75
--- /dev/null
+++ b/library/std/src/sys_common/mod.rs
@@ -0,0 +1,89 @@
+//! Platform-independent platform abstraction
+//!
+//! This is the platform-independent portion of the standard library's
+//! platform abstraction layer, whereas `std::sys` is the
+//! platform-specific portion.
+//!
+//! The relationship between `std::sys_common`, `std::sys` and the
+//! rest of `std` is complex, with dependencies going in all
+//! directions: `std` depending on `sys_common`, `sys_common`
+//! depending on `sys`, and `sys` depending on `sys_common` and `std`.
+//! This is because `sys_common` not only contains platform-independent code,
+//! but also code that is shared between the different platforms in `sys`.
+//! Ideally all that shared code should be moved to `sys::common`,
+//! and the dependencies between `std`, `sys_common` and `sys` all would form a dag.
+//! Progress on this is tracked in #84187.
+
+#![allow(missing_docs)]
+#![allow(missing_debug_implementations)]
+
+#[cfg(test)]
+mod tests;
+
+pub mod backtrace;
+pub mod condvar;
+pub mod fs;
+pub mod io;
+pub mod lazy_box;
+pub mod memchr;
+pub mod mutex;
+pub mod process;
+pub mod remutex;
+pub mod rwlock;
+pub mod thread;
+pub mod thread_info;
+pub mod thread_local_dtor;
+pub mod thread_local_key;
+pub mod thread_parker;
+pub mod wtf8;
+
+cfg_if::cfg_if! {
+    if #[cfg(any(target_os = "l4re",
+                 target_os = "hermit",
+                 feature = "restricted-std",
+                 all(target_family = "wasm", not(target_os = "emscripten")),
+                 all(target_vendor = "fortanix", target_env = "sgx")))] {
+        pub use crate::sys::net;
+    } else {
+        pub mod net;
+    }
+}
+
+// common error constructors
+
+/// A trait for viewing representations from std types
+#[doc(hidden)]
+pub trait AsInner<Inner: ?Sized> {
+    fn as_inner(&self) -> &Inner;
+}
+
+/// A trait for viewing representations from std types
+#[doc(hidden)]
+pub trait AsInnerMut<Inner: ?Sized> {
+    fn as_inner_mut(&mut self) -> &mut Inner;
+}
+
+/// A trait for extracting representations from std types
+#[doc(hidden)]
+pub trait IntoInner<Inner> {
+    fn into_inner(self) -> Inner;
+}
+
+/// A trait for creating std types from internal representations
+#[doc(hidden)]
+pub trait FromInner<Inner> {
+    fn from_inner(inner: Inner) -> Self;
+}
+
+// Computes (value*numer)/denom without overflow, as long as both
+// (numer*denom) and the overall result fit into i64 (which is the case
+// for our time conversions).
+#[allow(dead_code)] // not used on all platforms
+pub fn mul_div_u64(value: u64, numer: u64, denom: u64) -> u64 {
+    let q = value / denom;
+    let r = value % denom;
+    // Decompose value as (value/denom*denom + value%denom),
+    // substitute into (value*numer)/denom and simplify.
+    // r < denom, so (denom*numer) is the upper bound of (r*numer)
+    q * numer + r * numer / denom
+}