1 files changed, 102 insertions, 0 deletions
diff --git a/library/std/src/sys/wasi/stdio.rs b/library/std/src/sys/wasi/stdio.rs
new file mode 100644
index 00000000000..78e3911dc4e
--- /dev/null
+++ b/library/std/src/sys/wasi/stdio.rs
@@ -0,0 +1,102 @@
+use crate::io::{self, IoSlice, IoSliceMut};
+use crate::mem::ManuallyDrop;
+use crate::sys::fd::WasiFd;
+
+pub struct Stdin;
+pub struct Stdout;
+pub struct Stderr;
+
+impl Stdin {
+    pub fn new() -> io::Result<Stdin> {
+        Ok(Stdin)
+    }
+
+    #[inline]
+    pub fn as_raw_fd(&self) -> u32 {
+        0
+    }
+}
+
+impl io::Read for Stdin {
+    fn read(&mut self, data: &mut [u8]) -> io::Result<usize> {
+        self.read_vectored(&mut [IoSliceMut::new(data)])
+    }
+
+    fn read_vectored(&mut self, data: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
+        ManuallyDrop::new(unsafe { WasiFd::from_raw(self.as_raw_fd()) }).read(data)
+    }
+
+    #[inline]
+    fn is_read_vectored(&self) -> bool {
+        true
+    }
+}
+
+impl Stdout {
+    pub fn new() -> io::Result<Stdout> {
+        Ok(Stdout)
+    }
+
+    #[inline]
+    pub fn as_raw_fd(&self) -> u32 {
+        1
+    }
+}
+
+impl io::Write for Stdout {
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        self.write_vectored(&[IoSlice::new(data)])
+    }
+
+    fn write_vectored(&mut self, data: &[IoSlice<'_>]) -> io::Result<usize> {
+        ManuallyDrop::new(unsafe { WasiFd::from_raw(self.as_raw_fd()) }).write(data)
+    }
+
+    #[inline]
+    fn is_write_vectored(&self) -> bool {
+        true
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+impl Stderr {
+    pub fn new() -> io::Result<Stderr> {
+        Ok(Stderr)
+    }
+
+    #[inline]
+    pub fn as_raw_fd(&self) -> u32 {
+        2
+    }
+}
+
+impl io::Write for Stderr {
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        self.write_vectored(&[IoSlice::new(data)])
+    }
+
+    fn write_vectored(&mut self, data: &[IoSlice<'_>]) -> io::Result<usize> {
+        ManuallyDrop::new(unsafe { WasiFd::from_raw(self.as_raw_fd()) }).write(data)
+    }
+
+    #[inline]
+    fn is_write_vectored(&self) -> bool {
+        true
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+pub const STDIN_BUF_SIZE: usize = crate::sys_common::io::DEFAULT_BUF_SIZE;
+
+pub fn is_ebadf(err: &io::Error) -> bool {
+    err.raw_os_error() == Some(wasi::ERRNO_BADF.into())
+}
+
+pub fn panic_output() -> Option<impl io::Write> {
+    Stderr::new().ok()
+}