Cleanup readv & writev + tests

1 files changed, 78 insertions, 0 deletions

diff --git a/src/sys/uio.rs b/src/sys/uio.rs
new file mode 100644
index 00000000..322182c5
--- /dev/null
+++ b/src/sys/uio.rs
@@ -0,0 +1,78 @@
+
+mod ffi {
+    use super::IoVec;
+    use libc::{ssize_t];
+
+    // vectorized version of write
+    // doc: http://man7.org/linux/man-pages/man2/writev.2.html
+    pub fn writev(fd: Fd, iov: *const IoVec<&[u8]>, iovcnt: c_int) -> ssize_t;
+
+    // vectorized version of read
+    // doc: http://man7.org/linux/man-pages/man2/readv.2.html
+    pub fn readv(fd: Fd, iov: *const IoVec<&mut [u8]>, iovcnt: c_int) -> ssize_t;
+}
+
+pub fn writev(fd: Fd, iov: &[IoVec<&[u8]>]) -> NixResult<usize> {
+    let res = unsafe { ffi::writev(fd, iov.as_ptr(), iov.len() as c_int) };
+
+    if res < 0 {
+        return Err(NixError::Sys(Errno::last()));
+    }
+
+    return Ok(res as usize)
+}
+
+pub fn readv(fd: Fd, iov: &mut [IoVec<&mut [u8]>]) -> NixResult<usize> {
+    let res = unsafe { ffi::readv(fd, iov.as_ptr(), iov.len() as c_int) };
+    if res < 0 {
+        return Err(NixError::Sys(Errno::last()));
+    }
+
+    return Ok(res as usize)
+}
+
+#[repr(C)]
+pub struct IoVec<T> {
+    iov_base: *mut c_void,
+    iov_len: size_t,
+    phantom: PhantomData<T>
+}
+
+impl<T> IoVec<T> {
+    #[inline]
+    pub fn as_slice<'a>(&'a self) -> &'a [u8] {
+        use std::slice;
+
+        unsafe {
+            slice::from_raw_parts(
+                self.iov_base as *const u8,
+                self.iov_len as usize)
+        }
+    }
+}
+
+impl<'a> IoVec<&'a [u8]> {
+    pub fn from_slice(buf: &'a [u8]) -> IoVec<&'a [u8]> {
+        IoVec {
+            iov_base: buf.as_ptr() as *mut c_void,
+            iov_len: buf.len() as size_t,
+            phantom: PhantomData
+        }
+    }
+}
+
+impl<'a> IoVec<&'a mut [u8]> {
+    pub fn from_mut_slice(buf: &'a mut [u8]) -> IoVec<&'a mut [u8]> {
+        IoVec {
+            iov_base: buf.as_ptr() as *mut c_void,
+            iov_len: buf.len() as size_t,
+            phantom: PhantomData
+        }
+    }
+}
+
+#[test]
+pub fn test_size_of_io_vec() {
+    use nixtest;
+    nixtest::assert_size_of::<IoVec<&[u8]>>("iovec");
+}