From ed812c7addb8871d9f644604513679263cebc43f Mon Sep 17 00:00:00 2001
From: Dan Gohman <dev@sunfishcode.online>
Date: Tue, 13 Sep 2022 09:42:03 -0700
Subject: [PATCH] Add `AsFd` implementations for stdio lock types on WASI.

This mirrors the implementations on Unix platforms, and also mirrors the
existing `AsRawFd` impls.

This is similar to #100892, but is for the `*Lock` types.
---
 library/std/src/sys/wasi/stdio.rs | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/library/std/src/sys/wasi/stdio.rs b/library/std/src/sys/wasi/stdio.rs
index d2081771b6ec..07f5fbe38425 100644
--- a/library/std/src/sys/wasi/stdio.rs
+++ b/library/std/src/sys/wasi/stdio.rs
@@ -30,6 +30,13 @@ impl AsFd for Stdin {
     }
 }
 
+impl<'a> AsFd for StdinLock<'a> {
+    #[inline]
+    fn as_fd(&self) -> BorrowedFd<'_> {
+        unsafe { BorrowedFd::borrow_raw(0) }
+    }
+}
+
 impl io::Read for Stdin {
     fn read(&mut self, data: &mut [u8]) -> io::Result<usize> {
         self.read_vectored(&mut [IoSliceMut::new(data)])
@@ -65,6 +72,13 @@ impl AsFd for Stdout {
     }
 }
 
+impl<'a> AsFd for StdoutLock<'a> {
+    #[inline]
+    fn as_fd(&self) -> BorrowedFd<'_> {
+        unsafe { BorrowedFd::borrow_raw(1) }
+    }
+}
+
 impl io::Write for Stdout {
     fn write(&mut self, data: &[u8]) -> io::Result<usize> {
         self.write_vectored(&[IoSlice::new(data)])
@@ -103,6 +117,13 @@ impl AsFd for Stderr {
     }
 }
 
+impl<'a> AsFd for StderrLock<'a> {
+    #[inline]
+    fn as_fd(&self) -> BorrowedFd<'_> {
+        unsafe { BorrowedFd::borrow_raw(2) }
+    }
+}
+
 impl io::Write for Stderr {
     fn write(&mut self, data: &[u8]) -> io::Result<usize> {
         self.write_vectored(&[IoSlice::new(data)])