vexos: clean up Stdin read impl, use explicit cast in fs

Author: tropicaaal

library/std/src/sys/fs/vexos.rs

@@ -1,4 +1,4 @@
-use crate::ffi::OsString;
+use crate::ffi::{OsString, c_char};
 use crate::fmt;
 use crate::fs::TryLockError;
 use crate::hash::Hash;
@@ -342,9 +342,9 @@ impl File {
     }
 
     pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
-        let len = buf.len() as _;
+        let len = buf.len() as u32;
         let buf_ptr = buf.as_mut_ptr();
-        let read = unsafe { vex_sdk::vexFileRead(buf_ptr.cast(), 1, len, self.fd.0) };
+        let read = unsafe { vex_sdk::vexFileRead(buf_ptr.cast::<c_char>(), 1, len, self.fd.0) };
 
         if read < 0 {
             Err(io::const_error!(io::ErrorKind::Other, "Could not read from file"))
@@ -367,10 +367,11 @@ impl File {
     }
 
     pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
-        let len = buf.len();
+        let len = buf.len() as u32;
         let buf_ptr = buf.as_ptr();
-        let written =
-            unsafe { vex_sdk::vexFileWrite(buf_ptr.cast_mut().cast(), 1, len as _, self.fd.0) };
+        let written = unsafe {
+            vex_sdk::vexFileWrite(buf_ptr.cast_mut().cast::<c_char>(), 1, len, self.fd.0)
+        };
 
         if written < 0 {
             Err(io::const_error!(io::ErrorKind::Other, "Could not write to file"))
@@ -516,9 +517,12 @@ pub fn lstat(p: &Path) -> io::Result<FileAttr> {
     stat(p)
 }
 
+// NOTE: Cannot use `copy` from `common` here, since we have no support
+// for `File::set_permissions`.
 pub fn copy(from: &Path, to: &Path) -> io::Result<u64> {
     use crate::fs::File;
 
+    // If `from` is a directory, this call should fail.
     let mut reader = File::open(from)?;
     let mut writer = File::create(to)?;
 

library/std/src/sys/stdio/vexos.rs

@@ -16,9 +16,7 @@ impl io::Read for Stdin {
     fn read(&mut self, mut buf: &mut [u8]) -> io::Result<usize> {
         let mut count = 0;
 
-        while let Some((out_byte, new_buf)) = buf.split_first_mut() {
-            buf = new_buf;
-
+        for out_byte in buf.iter_mut() {
             let byte = unsafe { vex_sdk::vexSerialReadChar(STDIO_CHANNEL) };
             if byte < 0 {
                 break;

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

@@ -145,7 +145,6 @@ cfg_select! {
     target_os = "dragonfly",
     target_os = "hurd",
     target_os = "fuchsia",
-    target_os = "vexos",
     target_os = "vxworks",
     all(target_os = "wasi", target_env = "p2"),
 )))]

library/std/src/sys/thread/vexos.rs

@@ -1,4 +1,4 @@
-use crate::time::Duration;
+use crate::time::{Duration, Instant};
 
 pub fn yield_now() {
     unsafe {