From 63bebaa8c08eea3e54a0147d5d6d8b95573d6bb4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafael=20=C3=81vila=20de=20Esp=C3=ADndola?=
 <rafael@espindo.la>
Date: Thu, 12 Jul 2018 19:03:47 -0700
Subject: [PATCH] Implement IntoBuf for mut slices. (#214)

With this if foo is a mutable slice, it is possible to do

foo.into_buf().put_u32_le(42);

Before this patch into_buf would create a Cursor<&'a [u8]> and it
would not be possible to write into it.
---
 src/buf/into_buf.rs | 8 ++++++++
 tests/test_bytes.rs | 9 ++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/buf/into_buf.rs b/src/buf/into_buf.rs
index 1071908..4c3b420 100644
--- a/src/buf/into_buf.rs
+++ b/src/buf/into_buf.rs
@@ -63,6 +63,14 @@ impl<'a> IntoBuf for &'a [u8] {
     }
 }
 
+impl<'a> IntoBuf for &'a mut [u8] {
+    type Buf = io::Cursor<&'a mut [u8]>;
+
+    fn into_buf(self) -> Self::Buf {
+        io::Cursor::new(self)
+    }
+}
+
 impl<'a> IntoBuf for &'a str {
     type Buf = io::Cursor<&'a [u8]>;
 
diff --git a/tests/test_bytes.rs b/tests/test_bytes.rs
index 03da9dd..c0cba6b 100644
--- a/tests/test_bytes.rs
+++ b/tests/test_bytes.rs
@@ -1,6 +1,6 @@
 extern crate bytes;
 
-use bytes::{Bytes, BytesMut, BufMut};
+use bytes::{Bytes, BytesMut, BufMut, IntoBuf};
 
 const LONG: &'static [u8] = b"mary had a little lamb, little lamb, little lamb";
 const SHORT: &'static [u8] = b"hello world";
@@ -303,6 +303,13 @@ fn fns_defined_for_bytes_mut() {
     assert_eq!(&v[..], bytes);
 }
 
+#[test]
+fn mut_into_buf() {
+    let mut v = vec![0, 0, 0, 0];
+    let s = &mut v[..];
+    s.into_buf().put_u32_le(42);
+}
+
 #[test]
 fn reserve_convert() {
     // Inline -> Vec