impl Deref/DerefMut for IoVec types

Returning &'a mut [u8] was unsound, and we may as well just have them
directly deref to their slices to make it easier to work with them.

13 files changed, 53 insertions, 47 deletions

diff --git a/src/libstd/io/buffered.rs b/src/libstd/io/buffered.rs
index a5edc4360ca..d8a5f5a4d8c 100644
--- a/src/libstd/io/buffered.rs
+++ b/src/libstd/io/buffered.rs
@@ -236,7 +236,7 @@ impl<R: Read> Read for BufReader<R> {
     }
 
     fn read_vectored(&mut self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
-        let total_len = bufs.iter().map(|b| b.as_slice().len()).sum::<usize>();
+        let total_len = bufs.iter().map(|b| b.len()).sum::<usize>();
         if self.pos == self.cap && total_len >= self.buf.len() {
             return self.inner.read_vectored(bufs);
         }
@@ -595,7 +595,7 @@ impl<W: Write> Write for BufWriter<W> {
     }
 
     fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
-        let total_len = bufs.iter().map(|b| b.as_slice().len()).sum::<usize>();
+        let total_len = bufs.iter().map(|b| b.len()).sum::<usize>();
         if self.buf.len() + total_len > self.buf.capacity() {
             self.flush_buf()?;
         }
diff --git a/src/libstd/io/cursor.rs b/src/libstd/io/cursor.rs
index ef636cc6f8c..d1739894a27 100644
--- a/src/libstd/io/cursor.rs
+++ b/src/libstd/io/cursor.rs
@@ -224,7 +224,6 @@ impl<T> Read for Cursor<T> where T: AsRef<[u8]> {
     fn read_vectored(&mut self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
         let mut nread = 0;
         for buf in bufs {
-            let buf = buf.as_mut_slice();
             let n = self.read(buf)?;
             nread += n;
             if n < buf.len() {
@@ -272,7 +271,6 @@ fn slice_write_vectored(
 {
     let mut nwritten = 0;
     for buf in bufs {
-        let buf = buf.as_slice();
         let n = slice_write(pos_mut, slice, buf)?;
         nwritten += n;
         if n < buf.len() {
@@ -317,7 +315,7 @@ fn vec_write_vectored(
 {
     let mut nwritten = 0;
     for buf in bufs {
-        nwritten += vec_write(pos_mut, vec, buf.as_slice())?;
+        nwritten += vec_write(pos_mut, vec, buf)?;
     }
     Ok(nwritten)
 }
diff --git a/src/libstd/io/impls.rs b/src/libstd/io/impls.rs
index 4bba4af77c4..57d8cf40a79 100644
--- a/src/libstd/io/impls.rs
+++ b/src/libstd/io/impls.rs
@@ -196,7 +196,7 @@ impl<'a> Read for &'a [u8] {
     fn read_vectored(&mut self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
         let mut nread = 0;
         for buf in bufs {
-            nread += self.read(buf.as_mut_slice())?;
+            nread += self.read(buf)?;
             if self.is_empty() {
                 break;
             }
@@ -269,7 +269,7 @@ impl<'a> Write for &'a mut [u8] {
     fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
         let mut nwritten = 0;
         for buf in bufs {
-            nwritten += self.write(buf.as_slice())?;
+            nwritten += self.write(buf)?;
             if self.is_empty() {
                 break;
             }
@@ -303,10 +303,10 @@ impl Write for Vec<u8> {
 
     #[inline]
     fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
-        let len = bufs.iter().map(|b| b.as_slice().len()).sum();
+        let len = bufs.iter().map(|b| b.len()).sum();
         self.reserve(len);
         for buf in bufs {
-            self.extend_from_slice(buf.as_slice());
+            self.extend_from_slice(buf);
         }
         Ok(len)
     }
diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index b9765605f8e..7f9c5a0316c 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -264,6 +264,7 @@ use fmt;
 use slice;
 use str;
 use memchr;
+use ops::{Deref, DerefMut};
 use ptr;
 use sys;
 
@@ -531,7 +532,7 @@ pub trait Read {
     /// `read`.
     #[unstable(feature = "iovec", issue = "0")]
     fn read_vectored(&mut self, bufs: &mut [IoVecMut<'_>]) -> Result<usize> {
-        match bufs.iter_mut().map(|b| b.as_mut_slice()).find(|b| !b.is_empty()) {
+        match bufs.iter_mut().find(|b| !b.is_empty()) {
             Some(buf) => self.read(buf),
             None => Ok(0),
         }
@@ -896,7 +897,7 @@ pub struct IoVecMut<'a>(sys::io::IoVecMut<'a>);
 #[unstable(feature = "iovec", issue = "0")]
 impl<'a> fmt::Debug for IoVecMut<'a> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        fmt::Debug::fmt(self.as_slice(), fmt)
+        fmt::Debug::fmt(self.0.as_slice(), fmt)
     }
 }
 
@@ -911,18 +912,22 @@ impl<'a> IoVecMut<'a> {
     pub fn new(buf: &'a mut [u8]) -> IoVecMut<'a> {
         IoVecMut(sys::io::IoVecMut::new(buf))
     }
+}
+
+#[unstable(feature = "iovec", issue = "0")]
+impl<'a> Deref for IoVecMut<'a> {
+    type Target = [u8];
 
-    /// Returns a shared reference to the inner slice.
-    #[unstable(feature = "iovec", issue = "0")]
     #[inline]
-    pub fn as_slice(&self) -> &'a [u8] {
+    fn deref(&self) -> &[u8] {
         self.0.as_slice()
     }
+}
 
-    /// Returns a mutable reference to the inner slice.
-    #[unstable(feature = "iovec", issue = "0")]
+#[unstable(feature = "iovec", issue = "0")]
+impl<'a> DerefMut for IoVecMut<'a> {
     #[inline]
-    pub fn as_mut_slice(&mut self) -> &'a mut [u8] {
+    fn deref_mut(&mut self) -> &mut [u8] {
         self.0.as_mut_slice()
     }
 }
@@ -939,7 +944,7 @@ pub struct IoVec<'a>(sys::io::IoVec<'a>);
 #[unstable(feature = "iovec", issue = "0")]
 impl<'a> fmt::Debug for IoVec<'a> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        fmt::Debug::fmt(self.as_slice(), fmt)
+        fmt::Debug::fmt(self.0.as_slice(), fmt)
     }
 }
 
@@ -954,11 +959,14 @@ impl<'a> IoVec<'a> {
     pub fn new(buf: &'a [u8]) -> IoVec<'a> {
         IoVec(sys::io::IoVec::new(buf))
     }
+}
+
+#[unstable(feature = "iovec", issue = "0")]
+impl<'a> Deref for IoVec<'a> {
+    type Target = [u8];
 
-    /// Returns a shared reference to the inner slice.
-    #[unstable(feature = "iovec", issue = "0")]
     #[inline]
-    pub fn as_slice(&self) -> &'a [u8] {
+    fn deref(&self) -> &[u8] {
         self.0.as_slice()
     }
 }
@@ -1103,7 +1111,7 @@ pub trait Write {
     /// `write`.
     #[unstable(feature = "iovec", issue = "0")]
     fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> Result<usize> {
-        match bufs.iter().map(|b| b.as_slice()).find(|b| !b.is_empty()) {
+        match bufs.iter().find(|b| !b.is_empty()) {
             Some(buf) => self.write(buf),
             None => Ok(0),
         }
@@ -1813,7 +1821,7 @@ impl<T: Read, U: Read> Read for Chain<T, U> {
     fn read_vectored(&mut self, bufs: &mut [IoVecMut<'_>]) -> Result<usize> {
         if !self.done_first {
             match self.first.read_vectored(bufs)? {
-                0 if bufs.iter().any(|b| !b.as_slice().is_empty()) => self.done_first = true,
+                0 if bufs.iter().any(|b| !b.is_empty()) => self.done_first = true,
                 n => return Ok(n),
             }
         }
diff --git a/src/libstd/io/util.rs b/src/libstd/io/util.rs
index 6743018793f..5ce955eb1e4 100644
--- a/src/libstd/io/util.rs
+++ b/src/libstd/io/util.rs
@@ -156,7 +156,7 @@ impl Read for Repeat {
     fn read_vectored(&mut self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
         let mut nwritten = 0;
         for buf in bufs {
-            nwritten += self.read(buf.as_mut_slice())?;
+            nwritten += self.read(buf)?;
         }
         Ok(nwritten)
     }
@@ -207,7 +207,7 @@ impl Write for Sink {
 
     #[inline]
     fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
-        let total_len = bufs.iter().map(|b| b.as_slice().len()).sum();
+        let total_len = bufs.iter().map(|b| b.len()).sum();
         Ok(total_len)
     }
 
diff --git a/src/libstd/sys/cloudabi/io.rs b/src/libstd/sys/cloudabi/io.rs
index 9ee5788c580..8b02d3fd19d 100644
--- a/src/libstd/sys/cloudabi/io.rs
+++ b/src/libstd/sys/cloudabi/io.rs
@@ -7,7 +7,7 @@ impl<'a> IoVec<'a> {
     }
 
     #[inline]
-    pub fn as_slice(&self) -> &'a [u8] {
+    pub fn as_slice(&self) -> &[u8] {
         self.0
     }
 }
@@ -21,12 +21,12 @@ impl<'a> IoVecMut<'a> {
     }
 
     #[inline]
-    pub fn as_slice(&self) -> &'a [u8] {
+    pub fn as_slice(&self) -> &[u8] {
         self.0
     }
 
     #[inline]
-    pub fn as_mut_slice(&mut self) -> &'a mut [u8] {
+    pub fn as_mut_slice(&mut self) -> &mut [u8] {
         self.0
     }
 }
diff --git a/src/libstd/sys/redox/io.rs b/src/libstd/sys/redox/io.rs
index 9ee5788c580..8b02d3fd19d 100644
--- a/src/libstd/sys/redox/io.rs
+++ b/src/libstd/sys/redox/io.rs
@@ -7,7 +7,7 @@ impl<'a> IoVec<'a> {
     }
 
     #[inline]
-    pub fn as_slice(&self) -> &'a [u8] {
+    pub fn as_slice(&self) -> &[u8] {
         self.0
     }
 }
@@ -21,12 +21,12 @@ impl<'a> IoVecMut<'a> {
     }
 
     #[inline]
-    pub fn as_slice(&self) -> &'a [u8] {
+    pub fn as_slice(&self) -> &[u8] {
         self.0
     }
 
     #[inline]
-    pub fn as_mut_slice(&mut self) -> &'a mut [u8] {
+    pub fn as_mut_slice(&mut self) -> &mut [u8] {
         self.0
     }
 }
diff --git a/src/libstd/sys/redox/net/tcp.rs b/src/libstd/sys/redox/net/tcp.rs
index 08e12dc1ab1..4396a6f963c 100644
--- a/src/libstd/sys/redox/net/tcp.rs
+++ b/src/libstd/sys/redox/net/tcp.rs
@@ -35,7 +35,7 @@ impl TcpStream {
     }
 
     pub fn read_vectored(&self, buf: &mut [IoVecMut<'_>]) -> io::Result<usize> {
-        match buf.iter_mut().map(|b| b.as_mut_slice()).find(|b| !b.is_empty()) {
+        match buf.iter_mut().find(|b| !b.is_empty()) {
             Some(buf) => self.read(buf),
             None => Ok(0),
         }
@@ -46,7 +46,7 @@ impl TcpStream {
     }
 
     pub fn write_vectored(&self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
-        match buf.iter().map(|b| b.as_slice()).find(|b| !b.is_empty()) {
+        match buf.iter().find(|b| !b.is_empty()) {
             Some(buf) => self.write(buf),
             None => Ok(0),
         }
diff --git a/src/libstd/sys/sgx/io.rs b/src/libstd/sys/sgx/io.rs
index 9ee5788c580..8b02d3fd19d 100644
--- a/src/libstd/sys/sgx/io.rs
+++ b/src/libstd/sys/sgx/io.rs
@@ -7,7 +7,7 @@ impl<'a> IoVec<'a> {
     }
 
     #[inline]
-    pub fn as_slice(&self) -> &'a [u8] {
+    pub fn as_slice(&self) -> &[u8] {
         self.0
     }
 }
@@ -21,12 +21,12 @@ impl<'a> IoVecMut<'a> {
     }
 
     #[inline]
-    pub fn as_slice(&self) -> &'a [u8] {
+    pub fn as_slice(&self) -> &[u8] {
         self.0
     }
 
     #[inline]
-    pub fn as_mut_slice(&mut self) -> &'a mut [u8] {
+    pub fn as_mut_slice(&mut self) -> &mut [u8] {
         self.0
     }
 }
diff --git a/src/libstd/sys/sgx/net.rs b/src/libstd/sys/sgx/net.rs
index 2ecae1d746f..f46ed022b21 100644
--- a/src/libstd/sys/sgx/net.rs
+++ b/src/libstd/sys/sgx/net.rs
@@ -105,7 +105,7 @@ impl TcpStream {
 
     pub fn read_vectored(&self, buf: &mut [IoVecMut<'_>]) -> io::Result<usize> {
         let buf = match buf.get(0) {
-            Some(buf) => buf.as_mut_slice(),
+            Some(buf) => buf,
             None => return Ok(0),
         };
         self.read(buf)
@@ -117,7 +117,7 @@ impl TcpStream {
 
     pub fn write_vectored(&self, buf: &[IoVec<'_>]) -> io::Result<usize> {
         let buf = match buf.get(0) {
-            Some(buf) => buf.as_slice(),
+            Some(buf) => buf,
             None => return Ok(0),
         };
         self.read(buf)
diff --git a/src/libstd/sys/unix/io.rs b/src/libstd/sys/unix/io.rs
index 69b2db82ea3..65e4c6e0577 100644
--- a/src/libstd/sys/unix/io.rs
+++ b/src/libstd/sys/unix/io.rs
@@ -21,7 +21,7 @@ impl<'a> IoVec<'a> {
     }
 
     #[inline]
-    pub fn as_slice(&self) -> &'a [u8] {
+    pub fn as_slice(&self) -> &[u8] {
         unsafe {
             slice::from_raw_parts(self.vec.iov_base as *mut u8, self.vec.iov_len)
         }
@@ -46,14 +46,14 @@ impl<'a> IoVecMut<'a> {
     }
 
     #[inline]
-    pub fn as_slice(&self) -> &'a [u8] {
+    pub fn as_slice(&self) -> &[u8] {
         unsafe {
             slice::from_raw_parts(self.vec.iov_base as *mut u8, self.vec.iov_len)
         }
     }
 
     #[inline]
-    pub fn as_mut_slice(&mut self) -> &'a mut [u8] {
+    pub fn as_mut_slice(&mut self) -> &mut [u8] {
         unsafe {
             slice::from_raw_parts_mut(self.vec.iov_base as *mut u8, self.vec.iov_len)
         }
diff --git a/src/libstd/sys/wasm/io.rs b/src/libstd/sys/wasm/io.rs
index 9ee5788c580..8b02d3fd19d 100644
--- a/src/libstd/sys/wasm/io.rs
+++ b/src/libstd/sys/wasm/io.rs
@@ -7,7 +7,7 @@ impl<'a> IoVec<'a> {
     }
 
     #[inline]
-    pub fn as_slice(&self) -> &'a [u8] {
+    pub fn as_slice(&self) -> &[u8] {
         self.0
     }
 }
@@ -21,12 +21,12 @@ impl<'a> IoVecMut<'a> {
     }
 
     #[inline]
-    pub fn as_slice(&self) -> &'a [u8] {
+    pub fn as_slice(&self) -> &[u8] {
         self.0
     }
 
     #[inline]
-    pub fn as_mut_slice(&mut self) -> &'a mut [u8] {
+    pub fn as_mut_slice(&mut self) -> &mut [u8] {
         self.0
     }
 }
diff --git a/src/libstd/sys/windows/io.rs b/src/libstd/sys/windows/io.rs
index a14bfea9a21..662e3047923 100644
--- a/src/libstd/sys/windows/io.rs
+++ b/src/libstd/sys/windows/io.rs
@@ -22,7 +22,7 @@ impl<'a> IoVec<'a> {
     }
 
     #[inline]
-    pub fn as_slice(&self) -> &'a [u8] {
+    pub fn as_slice(&self) -> &[u8] {
         unsafe {
             slice::from_raw_parts(self.vec.buf as *mut u8, self.vec.len as usize)
         }
@@ -48,14 +48,14 @@ impl<'a> IoVecMut<'a> {
     }
 
     #[inline]
-    pub fn as_slice(&self) -> &'a [u8] {
+    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) -> &'a mut [u8] {
+    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)
         }