Rollup merge of #135696 - joboet:move_pal_io, r=Noratrieb

std: move `io` module out of `pal`, get rid of `sys_common::io`

Part of #117276.

This does two related things:
1. It moves the platform-specific definitions for `IoSlice`, `IoSliceMut` and `is_terminal` out of `pal` and into `sys` and unifies some of them.
2. It gets rid of `sys_common::io`, moving the non-platform-specific test helpers into `std::test_helpers` and the buffer size definition to the new `sys::io` module.

library/std/src/fs/tests.rs

@@ -14,7 +14,7 @@ use crate::os::unix::fs::symlink as junction_point;
 use crate::os::windows::fs::{OpenOptionsExt, junction_point, symlink_dir, symlink_file};
 use crate::path::Path;
 use crate::sync::Arc;
-use crate::sys_common::io::test::{TempDir, tmpdir};
+use crate::test_helpers::{TempDir, tmpdir};
 use crate::time::{Duration, Instant, SystemTime};
 use crate::{env, str, thread};
 

library/std/src/io/mod.rs

@@ -344,7 +344,7 @@ pub mod prelude;
 mod stdio;
 mod util;
 
-const DEFAULT_BUF_SIZE: usize = crate::sys_common::io::DEFAULT_BUF_SIZE;
+const DEFAULT_BUF_SIZE: usize = crate::sys::io::DEFAULT_BUF_SIZE;
 
 pub(crate) use stdio::cleanup;
 

library/std/src/lib.rs

@@ -739,27 +739,4 @@ mod sealed {
 
 #[cfg(test)]
 #[allow(dead_code)] // Not used in all configurations.
-pub(crate) mod test_helpers {
-    /// Test-only replacement for `rand::thread_rng()`, which is unusable for
-    /// us, as we want to allow running stdlib tests on tier-3 targets which may
-    /// not have `getrandom` support.
-    ///
-    /// Does a bit of a song and dance to ensure that the seed is different on
-    /// each call (as some tests sadly rely on this), but doesn't try that hard.
-    ///
-    /// This is duplicated in the `core`, `alloc` test suites (as well as
-    /// `std`'s integration tests), but figuring out a mechanism to share these
-    /// seems far more painful than copy-pasting a 7 line function a couple
-    /// times, given that even under a perma-unstable feature, I don't think we
-    /// want to expose types from `rand` from `std`.
-    #[track_caller]
-    pub(crate) fn test_rng() -> rand_xorshift::XorShiftRng {
-        use core::hash::{BuildHasher, Hash, Hasher};
-        let mut hasher = crate::hash::RandomState::new().build_hasher();
-        core::panic::Location::caller().hash(&mut hasher);
-        let hc64 = hasher.finish();
-        let seed_vec = hc64.to_le_bytes().into_iter().chain(0u8..8).collect::<Vec<u8>>();
-        let seed: [u8; 16] = seed_vec.as_slice().try_into().unwrap();
-        rand::SeedableRng::from_seed(seed)
-    }
-}
+pub(crate) mod test_helpers;

library/std/src/os/unix/fs/tests.rs

@@ -3,7 +3,7 @@ use super::*;
 #[test]
 fn read_vectored_at() {
     let msg = b"preadv is working!";
-    let dir = crate::sys_common::io::test::tmpdir();
+    let dir = crate::test_helpers::tmpdir();
 
     let filename = dir.join("preadv.txt");
     {
@@ -31,7 +31,7 @@ fn read_vectored_at() {
 #[test]
 fn write_vectored_at() {
     let msg = b"pwritev is not working!";
-    let dir = crate::sys_common::io::test::tmpdir();
+    let dir = crate::test_helpers::tmpdir();
 
     let filename = dir.join("preadv.txt");
     {

library/std/src/os/unix/net/tests.rs

@@ -7,7 +7,7 @@ use crate::os::android::net::{SocketAddrExt, UnixSocketExt};
 use crate::os::linux::net::{SocketAddrExt, UnixSocketExt};
 #[cfg(any(target_os = "android", target_os = "linux"))]
 use crate::os::unix::io::AsRawFd;
-use crate::sys_common::io::test::tmpdir;
+use crate::test_helpers::tmpdir;
 use crate::thread;
 use crate::time::Duration;
 

library/std/src/process/tests.rs

@@ -549,7 +549,7 @@ fn debug_print() {
 #[test]
 #[cfg(windows)]
 fn run_bat_script() {
-    let tempdir = crate::sys_common::io::test::tmpdir();
+    let tempdir = crate::test_helpers::tmpdir();
     let script_path = tempdir.join("hello.cmd");
 
     crate::fs::write(&script_path, "@echo Hello, %~1!").unwrap();
@@ -568,7 +568,7 @@ fn run_bat_script() {
 #[test]
 #[cfg(windows)]
 fn run_canonical_bat_script() {
-    let tempdir = crate::sys_common::io::test::tmpdir();
+    let tempdir = crate::test_helpers::tmpdir();
     let script_path = tempdir.join("hello.cmd");
 
     crate::fs::write(&script_path, "@echo Hello, %~1!").unwrap();

library/std/src/sys/io/io_slice/iovec.rs

@@ -1,8 +1,13 @@
-use hermit_abi::{c_void, iovec};
+#[cfg(target_os = "hermit")]
+use hermit_abi::iovec;
+#[cfg(target_family = "unix")]
+use libc::iovec;
 
+use crate::ffi::c_void;
 use crate::marker::PhantomData;
-use crate::os::hermit::io::{AsFd, AsRawFd};
 use crate::slice;
+#[cfg(target_os = "solid_asp3")]
+use crate::sys::pal::abi::sockets::iovec;
 
 #[derive(Copy, Clone)]
 #[repr(transparent)]
@@ -80,8 +85,3 @@ impl<'a> IoSliceMut<'a> {
         unsafe { slice::from_raw_parts_mut(self.vec.iov_base as *mut u8, self.vec.iov_len) }
     }
 }
-
-pub fn is_terminal(fd: &impl AsFd) -> bool {
-    let fd = fd.as_fd();
-    hermit_abi::isatty(fd.as_raw_fd())
-}

library/std/src/sys/io/io_slice/unsupported.rs

@@ -50,7 +50,3 @@ impl<'a> IoSliceMut<'a> {
         self.0
     }
 }
-
-pub fn is_terminal<T>(_: &T) -> bool {
-    false
-}

library/std/src/sys/io/io_slice/wasi.rs

@@ -1,7 +1,4 @@
-#![forbid(unsafe_op_in_unsafe_fn)]
-
 use crate::marker::PhantomData;
-use crate::os::fd::{AsFd, AsRawFd};
 use crate::slice;
 
 #[derive(Copy, Clone)]
@@ -77,8 +74,3 @@ impl<'a> IoSliceMut<'a> {
         unsafe { slice::from_raw_parts_mut(self.vec.buf as *mut u8, self.vec.buf_len) }
     }
 }
-
-pub fn is_terminal(fd: &impl AsFd) -> bool {
-    let fd = fd.as_fd();
-    unsafe { libc::isatty(fd.as_raw_fd()) != 0 }
-}

library/std/src/sys/io/io_slice/windows.rs

@@ -1,86 +1,82 @@
-use libc::c_void;
-
-use super::abi::sockets::iovec;
 use crate::marker::PhantomData;
 use crate::slice;
+use crate::sys::c;
 
 #[derive(Copy, Clone)]
 #[repr(transparent)]
 pub struct IoSlice<'a> {
-    vec: iovec,
+    vec: c::WSABUF,
     _p: PhantomData<&'a [u8]>,
 }
 
 impl<'a> IoSlice<'a> {
     #[inline]
     pub fn new(buf: &'a [u8]) -> IoSlice<'a> {
+        assert!(buf.len() <= u32::MAX as usize);
         IoSlice {
-            vec: iovec { iov_base: buf.as_ptr() as *mut u8 as *mut c_void, iov_len: buf.len() },
+            vec: c::WSABUF { len: buf.len() as u32, buf: buf.as_ptr() as *mut u8 },
             _p: PhantomData,
         }
     }
 
     #[inline]
     pub fn advance(&mut self, n: usize) {
-        if self.vec.iov_len < n {
+        if (self.vec.len as usize) < n {
             panic!("advancing IoSlice beyond its length");
         }
 
         unsafe {
-            self.vec.iov_len -= n;
-            self.vec.iov_base = self.vec.iov_base.add(n);
+            self.vec.len -= n as u32;
+            self.vec.buf = self.vec.buf.add(n);
         }
     }
 
     #[inline]
     pub const fn as_slice(&self) -> &'a [u8] {
-        unsafe { slice::from_raw_parts(self.vec.iov_base as *mut u8, self.vec.iov_len) }
+        unsafe { slice::from_raw_parts(self.vec.buf, self.vec.len as usize) }
     }
 }
 
 #[repr(transparent)]
 pub struct IoSliceMut<'a> {
-    vec: iovec,
+    vec: c::WSABUF,
     _p: PhantomData<&'a mut [u8]>,
 }
 
 impl<'a> IoSliceMut<'a> {
     #[inline]
     pub fn new(buf: &'a mut [u8]) -> IoSliceMut<'a> {
+        assert!(buf.len() <= u32::MAX as usize);
         IoSliceMut {
-            vec: iovec { iov_base: buf.as_mut_ptr() as *mut c_void, iov_len: buf.len() },
+            vec: c::WSABUF { len: buf.len() as u32, buf: buf.as_mut_ptr() },
             _p: PhantomData,
         }
     }
 
     #[inline]
     pub fn advance(&mut self, n: usize) {
-        if self.vec.iov_len < n {
+        if (self.vec.len as usize) < n {
             panic!("advancing IoSliceMut beyond its length");
         }
 
         unsafe {
-            self.vec.iov_len -= n;
-            self.vec.iov_base = self.vec.iov_base.add(n);
+            self.vec.len -= n as u32;
+            self.vec.buf = self.vec.buf.add(n);
         }
     }
 
     #[inline]
     pub fn as_slice(&self) -> &[u8] {
-        unsafe { slice::from_raw_parts(self.vec.iov_base as *mut u8, self.vec.iov_len) }
+        unsafe { slice::from_raw_parts(self.vec.buf, self.vec.len as usize) }
     }
 
     #[inline]
     pub const fn into_slice(self) -> &'a mut [u8] {
-        unsafe { slice::from_raw_parts_mut(self.vec.iov_base as *mut u8, self.vec.iov_len) }
+        unsafe { slice::from_raw_parts_mut(self.vec.buf, self.vec.len as usize) }
     }
 
     #[inline]
     pub fn as_mut_slice(&mut self) -> &mut [u8] {
-        unsafe { slice::from_raw_parts_mut(self.vec.iov_base as *mut u8, self.vec.iov_len) }
+        unsafe { slice::from_raw_parts_mut(self.vec.buf, self.vec.len as usize) }
     }
 }
-
-pub fn is_terminal<T>(_: &T) -> bool {
-    false
-}

library/std/src/sys/io/is_terminal/hermit.rs

@@ -0,0 +1,6 @@
+use crate::os::fd::{AsFd, AsRawFd};
+
+pub fn is_terminal(fd: &impl AsFd) -> bool {
+    let fd = fd.as_fd();
+    hermit_abi::isatty(fd.as_raw_fd())
+}

library/std/src/sys/io/is_terminal/isatty.rs

@@ -0,0 +1,6 @@
+use crate::os::fd::{AsFd, AsRawFd};
+
+pub fn is_terminal(fd: &impl AsFd) -> bool {
+    let fd = fd.as_fd();
+    unsafe { libc::isatty(fd.as_raw_fd()) != 0 }
+}

library/std/src/sys/io/is_terminal/unsupported.rs

@@ -0,0 +1,3 @@
+pub fn is_terminal<T>(_: &T) -> bool {
+    false
+}

library/std/src/sys/io/is_terminal/windows.rs

@@ -1,90 +1,8 @@
-use core::ffi::c_void;
-
-use crate::marker::PhantomData;
+use crate::ffi::c_void;
 use crate::mem::size_of;
 use crate::os::windows::io::{AsHandle, AsRawHandle, BorrowedHandle};
-use crate::slice;
 use crate::sys::c;
 
-#[derive(Copy, Clone)]
-#[repr(transparent)]
-pub struct IoSlice<'a> {
-    vec: c::WSABUF,
-    _p: PhantomData<&'a [u8]>,
-}
-
-impl<'a> IoSlice<'a> {
-    #[inline]
-    pub fn new(buf: &'a [u8]) -> IoSlice<'a> {
-        assert!(buf.len() <= u32::MAX as usize);
-        IoSlice {
-            vec: c::WSABUF { len: buf.len() as u32, buf: buf.as_ptr() as *mut u8 },
-            _p: PhantomData,
-        }
-    }
-
-    #[inline]
-    pub fn advance(&mut self, n: usize) {
-        if (self.vec.len as usize) < n {
-            panic!("advancing IoSlice beyond its length");
-        }
-
-        unsafe {
-            self.vec.len -= n as u32;
-            self.vec.buf = self.vec.buf.add(n);
-        }
-    }
-
-    #[inline]
-    pub const fn as_slice(&self) -> &'a [u8] {
-        unsafe { slice::from_raw_parts(self.vec.buf, self.vec.len as usize) }
-    }
-}
-
-#[repr(transparent)]
-pub struct IoSliceMut<'a> {
-    vec: c::WSABUF,
-    _p: PhantomData<&'a mut [u8]>,
-}
-
-impl<'a> IoSliceMut<'a> {
-    #[inline]
-    pub fn new(buf: &'a mut [u8]) -> IoSliceMut<'a> {
-        assert!(buf.len() <= u32::MAX as usize);
-        IoSliceMut {
-            vec: c::WSABUF { len: buf.len() as u32, buf: buf.as_mut_ptr() },
-            _p: PhantomData,
-        }
-    }
-
-    #[inline]
-    pub fn advance(&mut self, n: usize) {
-        if (self.vec.len as usize) < n {
-            panic!("advancing IoSliceMut beyond its length");
-        }
-
-        unsafe {
-            self.vec.len -= n as u32;
-            self.vec.buf = self.vec.buf.add(n);
-        }
-    }
-
-    #[inline]
-    pub fn as_slice(&self) -> &[u8] {
-        unsafe { slice::from_raw_parts(self.vec.buf, self.vec.len as usize) }
-    }
-
-    #[inline]
-    pub const fn into_slice(self) -> &'a mut [u8] {
-        unsafe { slice::from_raw_parts_mut(self.vec.buf, self.vec.len as usize) }
-    }
-
-    #[inline]
-    pub fn as_mut_slice(&mut self) -> &mut [u8] {
-        unsafe { slice::from_raw_parts_mut(self.vec.buf, self.vec.len as usize) }
-    }
-}
-
 pub fn is_terminal(h: &impl AsHandle) -> bool {
     handle_is_console(h.as_handle())
 }

library/std/src/sys/io/mod.rs

@@ -0,0 +1,44 @@
+#![forbid(unsafe_op_in_unsafe_fn)]
+
+mod io_slice {
+    cfg_if::cfg_if! {
+        if #[cfg(any(target_family = "unix", target_os = "hermit", target_os = "solid_asp3"))] {
+            mod iovec;
+            pub use iovec::*;
+        } else if #[cfg(target_os = "windows")] {
+            mod windows;
+            pub use windows::*;
+        } else if #[cfg(target_os = "wasi")] {
+            mod wasi;
+            pub use wasi::*;
+        } else {
+            mod unsupported;
+            pub use unsupported::*;
+        }
+    }
+}
+
+mod is_terminal {
+    cfg_if::cfg_if! {
+        if #[cfg(any(target_family = "unix", target_os = "wasi"))] {
+            mod isatty;
+            pub use isatty::*;
+        } else if #[cfg(target_os = "windows")] {
+            mod windows;
+            pub use windows::*;
+        } else if #[cfg(target_os = "hermit")] {
+            mod hermit;
+            pub use hermit::*;
+        } else {
+            mod unsupported;
+            pub use unsupported::*;
+        }
+    }
+}
+
+pub use io_slice::{IoSlice, IoSliceMut};
+pub use is_terminal::is_terminal;
+
+// Bare metal platforms usually have very small amounts of RAM
+// (in the order of hundreds of KB)
+pub const DEFAULT_BUF_SIZE: usize = if cfg!(target_os = "espidf") { 512 } else { 8 * 1024 };

library/std/src/sys/mod.rs

@@ -12,6 +12,7 @@ pub mod anonymous_pipe;
 pub mod backtrace;
 pub mod cmath;
 pub mod exit_guard;
+pub mod io;
 pub mod net;
 pub mod os_str;
 pub mod path;

library/std/src/sys/pal/hermit/mod.rs

@@ -23,7 +23,6 @@ pub mod env;
 pub mod fd;
 pub mod fs;
 pub mod futex;
-pub mod io;
 pub mod os;
 #[path = "../unsupported/pipe.rs"]
 pub mod pipe;

library/std/src/sys/pal/sgx/mod.rs

@@ -14,8 +14,6 @@ pub mod env;
 pub mod fd;
 #[path = "../unsupported/fs.rs"]
 pub mod fs;
-#[path = "../unsupported/io.rs"]
-pub mod io;
 mod libunwind_integration;
 pub mod os;
 #[path = "../unsupported/pipe.rs"]

library/std/src/sys/pal/sgx/stdio.rs

@@ -62,7 +62,7 @@ impl io::Write for Stderr {
     }
 }
 
-pub const STDIN_BUF_SIZE: usize = crate::sys_common::io::DEFAULT_BUF_SIZE;
+pub const STDIN_BUF_SIZE: usize = crate::sys::io::DEFAULT_BUF_SIZE;
 
 pub fn is_ebadf(err: &io::Error) -> bool {
     // FIXME: Rust normally maps Unix EBADF to `Uncategorized`

library/std/src/sys/pal/solid/mod.rs

@@ -23,7 +23,6 @@ pub mod env;
 // `crate::sys::error`
 pub(crate) mod error;
 pub mod fs;
-pub mod io;
 pub mod os;
 #[path = "../unsupported/pipe.rs"]
 pub mod pipe;

library/std/src/sys/pal/teeos/mod.rs

@@ -13,8 +13,6 @@ pub mod env;
 //pub mod fd;
 #[path = "../unsupported/fs.rs"]
 pub mod fs;
-#[path = "../unsupported/io.rs"]
-pub mod io;
 pub mod os;
 #[path = "../unsupported/pipe.rs"]
 pub mod pipe;

library/std/src/sys/pal/uefi/mod.rs

@@ -17,8 +17,6 @@ pub mod args;
 pub mod env;
 pub mod fs;
 pub mod helpers;
-#[path = "../unsupported/io.rs"]
-pub mod io;
 pub mod os;
 #[path = "../unsupported/pipe.rs"]
 pub mod pipe;

library/std/src/sys/pal/unix/io.rs

@@ -1,87 +0,0 @@
-use libc::{c_void, iovec};
-
-use crate::marker::PhantomData;
-use crate::os::fd::{AsFd, AsRawFd};
-use crate::slice;
-
-#[derive(Copy, Clone)]
-#[repr(transparent)]
-pub struct IoSlice<'a> {
-    vec: iovec,
-    _p: PhantomData<&'a [u8]>,
-}
-
-impl<'a> IoSlice<'a> {
-    #[inline]
-    pub fn new(buf: &'a [u8]) -> IoSlice<'a> {
-        IoSlice {
-            vec: iovec { iov_base: buf.as_ptr() as *mut u8 as *mut c_void, iov_len: buf.len() },
-            _p: PhantomData,
-        }
-    }
-
-    #[inline]
-    pub fn advance(&mut self, n: usize) {
-        if self.vec.iov_len < n {
-            panic!("advancing IoSlice beyond its length");
-        }
-
-        unsafe {
-            self.vec.iov_len -= n;
-            self.vec.iov_base = self.vec.iov_base.add(n);
-        }
-    }
-
-    #[inline]
-    pub const fn as_slice(&self) -> &'a [u8] {
-        unsafe { slice::from_raw_parts(self.vec.iov_base as *mut u8, self.vec.iov_len) }
-    }
-}
-
-#[repr(transparent)]
-pub struct IoSliceMut<'a> {
-    vec: iovec,
-    _p: PhantomData<&'a mut [u8]>,
-}
-
-impl<'a> IoSliceMut<'a> {
-    #[inline]
-    pub fn new(buf: &'a mut [u8]) -> IoSliceMut<'a> {
-        IoSliceMut {
-            vec: iovec { iov_base: buf.as_mut_ptr() as *mut c_void, iov_len: buf.len() },
-            _p: PhantomData,
-        }
-    }
-
-    #[inline]
-    pub fn advance(&mut self, n: usize) {
-        if self.vec.iov_len < n {
-            panic!("advancing IoSliceMut beyond its length");
-        }
-
-        unsafe {
-            self.vec.iov_len -= n;
-            self.vec.iov_base = self.vec.iov_base.add(n);
-        }
-    }
-
-    #[inline]
-    pub fn as_slice(&self) -> &[u8] {
-        unsafe { slice::from_raw_parts(self.vec.iov_base as *mut u8, self.vec.iov_len) }
-    }
-
-    #[inline]
-    pub const fn into_slice(self) -> &'a mut [u8] {
-        unsafe { slice::from_raw_parts_mut(self.vec.iov_base as *mut u8, self.vec.iov_len) }
-    }
-
-    #[inline]
-    pub fn as_mut_slice(&mut self) -> &mut [u8] {
-        unsafe { slice::from_raw_parts_mut(self.vec.iov_base as *mut u8, self.vec.iov_len) }
-    }
-}
-
-pub fn is_terminal(fd: &impl AsFd) -> bool {
-    let fd = fd.as_fd();
-    unsafe { libc::isatty(fd.as_raw_fd()) != 0 }
-}

library/std/src/sys/pal/unix/kernel_copy/tests.rs

@@ -2,7 +2,7 @@ use crate::fs::OpenOptions;
 use crate::io;
 use crate::io::{BufRead, Read, Result, Seek, SeekFrom, Write};
 use crate::os::unix::io::AsRawFd;
-use crate::sys_common::io::test::tmpdir;
+use crate::test_helpers::tmpdir;
 
 #[test]
 fn copy_specialization() -> Result<()> {

library/std/src/sys/pal/unix/mod.rs

@@ -11,7 +11,6 @@ pub mod env;
 pub mod fd;
 pub mod fs;
 pub mod futex;
-pub mod io;
 #[cfg(any(target_os = "linux", target_os = "android"))]
 pub mod kernel_copy;
 #[cfg(target_os = "linux")]

library/std/src/sys/pal/unix/stdio.rs

@@ -92,7 +92,7 @@ pub fn is_ebadf(err: &io::Error) -> bool {
     err.raw_os_error() == Some(libc::EBADF as i32)
 }
 
-pub const STDIN_BUF_SIZE: usize = crate::sys_common::io::DEFAULT_BUF_SIZE;
+pub const STDIN_BUF_SIZE: usize = crate::sys::io::DEFAULT_BUF_SIZE;
 
 pub fn panic_output() -> Option<impl io::Write> {
     Some(Stderr::new())

library/std/src/sys/pal/unsupported/mod.rs

@@ -3,7 +3,6 @@
 pub mod args;
 pub mod env;
 pub mod fs;
-pub mod io;
 pub mod os;
 pub mod pipe;
 pub mod process;

library/std/src/sys/pal/wasi/mod.rs

@@ -20,7 +20,6 @@ pub mod fs;
 #[allow(unused)]
 #[path = "../wasm/atomics/futex.rs"]
 pub mod futex;
-pub mod io;
 
 pub mod os;
 #[path = "../unsupported/pipe.rs"]

library/std/src/sys/pal/wasi/stdio.rs

@@ -101,7 +101,7 @@ impl io::Write for Stderr {
     }
 }
 
-pub const STDIN_BUF_SIZE: usize = crate::sys_common::io::DEFAULT_BUF_SIZE;
+pub const STDIN_BUF_SIZE: usize = crate::sys::io::DEFAULT_BUF_SIZE;
 
 pub fn is_ebadf(err: &io::Error) -> bool {
     err.raw_os_error() == Some(wasi::ERRNO_BADF.raw().into())

library/std/src/sys/pal/wasip2/mod.rs

@@ -17,8 +17,6 @@ pub mod fs;
 #[allow(unused)]
 #[path = "../wasm/atomics/futex.rs"]
 pub mod futex;
-#[path = "../wasi/io.rs"]
-pub mod io;
 
 #[path = "../wasi/os.rs"]
 pub mod os;

library/std/src/sys/pal/wasm/mod.rs

@@ -21,8 +21,6 @@ pub mod args;
 pub mod env;
 #[path = "../unsupported/fs.rs"]
 pub mod fs;
-#[path = "../unsupported/io.rs"]
-pub mod io;
 #[path = "../unsupported/os.rs"]
 pub mod os;
 #[path = "../unsupported/pipe.rs"]

library/std/src/sys/pal/windows/mod.rs

@@ -21,7 +21,6 @@ pub mod fs;
 #[cfg(not(target_vendor = "win7"))]
 pub mod futex;
 pub mod handle;
-pub mod io;
 pub mod os;
 pub mod pipe;
 pub mod process;

library/std/src/sys/pal/windows/process/tests.rs

@@ -158,7 +158,7 @@ fn windows_exe_resolver() {
     use super::resolve_exe;
     use crate::io;
     use crate::sys::fs::symlink;
-    use crate::sys_common::io::test::tmpdir;
+    use crate::test_helpers::tmpdir;
 
     let env_paths = || env::var_os("PATH");
 

library/std/src/sys/pal/xous/mod.rs

@@ -5,8 +5,6 @@ pub mod args;
 pub mod env;
 #[path = "../unsupported/fs.rs"]
 pub mod fs;
-#[path = "../unsupported/io.rs"]
-pub mod io;
 pub mod os;
 #[path = "../unsupported/pipe.rs"]
 pub mod pipe;

library/std/src/sys/pal/zkvm/mod.rs

@@ -16,8 +16,6 @@ pub mod args;
 pub mod env;
 #[path = "../unsupported/fs.rs"]
 pub mod fs;
-#[path = "../unsupported/io.rs"]
-pub mod io;
 pub mod os;
 #[path = "../unsupported/pipe.rs"]
 pub mod pipe;

library/std/src/sys/pal/zkvm/stdio.rs

@@ -54,7 +54,7 @@ impl io::Write for Stderr {
     }
 }
 
-pub const STDIN_BUF_SIZE: usize = crate::sys_common::io::DEFAULT_BUF_SIZE;
+pub const STDIN_BUF_SIZE: usize = crate::sys::io::DEFAULT_BUF_SIZE;
 
 pub fn is_ebadf(_err: &io::Error) -> bool {
     true

library/std/src/sys_common/io.rs

@@ -1,49 +0,0 @@
-// Bare metal platforms usually have very small amounts of RAM
-// (in the order of hundreds of KB)
-pub const DEFAULT_BUF_SIZE: usize = if cfg!(target_os = "espidf") { 512 } else { 8 * 1024 };
-
-#[cfg(test)]
-#[allow(dead_code)] // not used on emscripten and wasi
-pub mod test {
-    use rand::RngCore;
-
-    use crate::path::{Path, PathBuf};
-    use crate::{env, fs, thread};
-
-    pub struct TempDir(PathBuf);
-
-    impl TempDir {
-        pub fn join(&self, path: &str) -> PathBuf {
-            let TempDir(ref p) = *self;
-            p.join(path)
-        }
-
-        pub fn path(&self) -> &Path {
-            let TempDir(ref p) = *self;
-            p
-        }
-    }
-
-    impl Drop for TempDir {
-        fn drop(&mut self) {
-            // Gee, seeing how we're testing the fs module I sure hope that we
-            // at least implement this correctly!
-            let TempDir(ref p) = *self;
-            let result = fs::remove_dir_all(p);
-            // Avoid panicking while panicking as this causes the process to
-            // immediately abort, without displaying test results.
-            if !thread::panicking() {
-                result.unwrap();
-            }
-        }
-    }
-
-    #[track_caller] // for `test_rng`
-    pub fn tmpdir() -> TempDir {
-        let p = env::temp_dir();
-        let mut r = crate::test_helpers::test_rng();
-        let ret = p.join(&format!("rust-{}", r.next_u32()));
-        fs::create_dir(&ret).unwrap();
-        TempDir(ret)
-    }
-}

library/std/src/sys_common/mod.rs

@@ -21,7 +21,6 @@
 mod tests;
 
 pub mod fs;
-pub mod io;
 pub mod process;
 pub mod wstr;
 pub mod wtf8;

library/std/src/test_helpers.rs

@@ -0,0 +1,65 @@
+use rand::{RngCore, SeedableRng};
+
+use crate::hash::{BuildHasher, Hash, Hasher, RandomState};
+use crate::panic::Location;
+use crate::path::{Path, PathBuf};
+use crate::{env, fs, thread};
+
+/// Test-only replacement for `rand::thread_rng()`, which is unusable for
+/// us, as we want to allow running stdlib tests on tier-3 targets which may
+/// not have `getrandom` support.
+///
+/// Does a bit of a song and dance to ensure that the seed is different on
+/// each call (as some tests sadly rely on this), but doesn't try that hard.
+///
+/// This is duplicated in the `core`, `alloc` test suites (as well as
+/// `std`'s integration tests), but figuring out a mechanism to share these
+/// seems far more painful than copy-pasting a 7 line function a couple
+/// times, given that even under a perma-unstable feature, I don't think we
+/// want to expose types from `rand` from `std`.
+#[track_caller]
+pub(crate) fn test_rng() -> rand_xorshift::XorShiftRng {
+    let mut hasher = RandomState::new().build_hasher();
+    Location::caller().hash(&mut hasher);
+    let hc64 = hasher.finish();
+    let seed_vec = hc64.to_le_bytes().into_iter().chain(0u8..8).collect::<Vec<u8>>();
+    let seed: [u8; 16] = seed_vec.as_slice().try_into().unwrap();
+    SeedableRng::from_seed(seed)
+}
+
+pub struct TempDir(PathBuf);
+
+impl TempDir {
+    pub fn join(&self, path: &str) -> PathBuf {
+        let TempDir(ref p) = *self;
+        p.join(path)
+    }
+
+    pub fn path(&self) -> &Path {
+        let TempDir(ref p) = *self;
+        p
+    }
+}
+
+impl Drop for TempDir {
+    fn drop(&mut self) {
+        // Gee, seeing how we're testing the fs module I sure hope that we
+        // at least implement this correctly!
+        let TempDir(ref p) = *self;
+        let result = fs::remove_dir_all(p);
+        // Avoid panicking while panicking as this causes the process to
+        // immediately abort, without displaying test results.
+        if !thread::panicking() {
+            result.unwrap();
+        }
+    }
+}
+
+#[track_caller] // for `test_rng`
+pub fn tmpdir() -> TempDir {
+    let p = env::temp_dir();
+    let mut r = test_rng();
+    let ret = p.join(&format!("rust-{}", r.next_u32()));
+    fs::create_dir(&ret).unwrap();
+    TempDir(ret)
+}

library/std/tests/common/mod.rs

@@ -18,7 +18,7 @@ pub(crate) fn test_rng() -> rand_xorshift::XorShiftRng {
     rand::SeedableRng::from_seed(seed)
 }
 
-// Copied from std::sys_common::io
+// Copied from std::test_helpers
 pub(crate) struct TempDir(PathBuf);
 
 impl TempDir {