Add template for Windows impl

src/sys/windows/host_impl.rs

@@ -0,0 +1,84 @@
+//! WASI host types specific to Windows host.
+#![allow(non_camel_case_types)]
+#![allow(non_snake_case)]
+#![allow(unused)]
+use crate::host;
+
+use std::marker::PhantomData;
+use std::slice;
+use winapi::shared::{ntdef, ws2def};
+
+// these will be obsolete once https://github.com/rust-lang/rust/pull/60334
+// lands in stable
+pub struct IoVec<'a> {
+    vec: ws2def::WSABUF,
+    _p: PhantomData<&'a [u8]>,
+}
+
+pub struct IoVecMut<'a> {
+    vec: ws2def::WSABUF,
+    _p: PhantomData<&'a mut [u8]>,
+}
+
+impl<'a> IoVec<'a> {
+    #[inline]
+    pub fn new(buf: &'a [u8]) -> Self {
+        assert!(buf.len() <= ntdef::ULONG::max_value() as usize);
+        Self {
+            vec: ws2def::WSABUF {
+                len: buf.len() as ntdef::ULONG,
+                buf: buf.as_ptr() as *mut u8 as *mut ntdef::CHAR,
+            },
+            _p: PhantomData,
+        }
+    }
+
+    #[inline]
+    pub fn as_slice(&self) -> &[u8] {
+        unsafe { slice::from_raw_parts(self.vec.buf as *mut u8, self.vec.len as usize) }
+    }
+}
+
+impl<'a> IoVecMut<'a> {
+    #[inline]
+    pub fn new(buf: &'a mut [u8]) -> Self {
+        assert!(buf.len() <= ntdef::ULONG::max_value() as usize);
+        Self {
+            vec: ws2def::WSABUF {
+                len: buf.len() as ntdef::ULONG,
+                buf: buf.as_mut_ptr() as *mut u8 as *mut ntdef::CHAR,
+            },
+            _p: PhantomData,
+        }
+    }
+
+    #[inline]
+    pub fn as_slice(&self) -> &[u8] {
+        unsafe { slice::from_raw_parts(self.vec.buf as *mut u8, self.vec.len as usize) }
+    }
+
+    #[inline]
+    pub fn as_mut_slice(&mut self) -> &mut [u8] {
+        unsafe { slice::from_raw_parts_mut(self.vec.buf as *mut u8, self.vec.len as usize) }
+    }
+}
+
+pub unsafe fn ciovec_to_win<'a>(ciovec: &'a host::__wasi_ciovec_t) -> IoVec<'a> {
+    let slice = slice::from_raw_parts(ciovec.buf as *const u8, ciovec.buf_len);
+    IoVec::new(slice)
+}
+
+pub unsafe fn ciovec_to_win_mut<'a>(ciovec: &'a mut host::__wasi_ciovec_t) -> IoVecMut<'a> {
+    let slice = slice::from_raw_parts_mut(ciovec.buf as *mut u8, ciovec.buf_len);
+    IoVecMut::new(slice)
+}
+
+pub unsafe fn iovec_to_win<'a>(iovec: &'a host::__wasi_iovec_t) -> IoVec<'a> {
+    let slice = slice::from_raw_parts(iovec.buf as *const u8, iovec.buf_len);
+    IoVec::new(slice)
+}
+
+pub unsafe fn iovec_to_win_mut<'a>(iovec: &'a mut host::__wasi_iovec_t) -> IoVecMut<'a> {
+    let slice = slice::from_raw_parts_mut(iovec.buf as *mut u8, iovec.buf_len);
+    IoVecMut::new(slice)
+}