From 4ca7e0fabf3717a033bb57698164caa0f84bb79f Mon Sep 17 00:00:00 2001
From: Carl Lerche <me@carllerche.com>
Date: Sun, 25 Sep 2016 22:33:49 -0700
Subject: [PATCH] Add IntoBuf trait

---
 examples/into_buf.rs | 17 +++++++++++++++++
 src/imp/buf/mod.rs   | 34 ++++++++++++++++++++++++++++++++++
 src/imp/bytes/mod.rs | 16 +++++++++++++++-
 src/lib.rs           |  2 +-
 4 files changed, 67 insertions(+), 2 deletions(-)
 create mode 100644 examples/into_buf.rs

diff --git a/examples/into_buf.rs b/examples/into_buf.rs
new file mode 100644
index 0000000..753a5ad
--- /dev/null
+++ b/examples/into_buf.rs
@@ -0,0 +1,17 @@
+extern crate bytes;
+
+use bytes::{Buf, IntoBuf, Bytes};
+
+pub fn dump<T>(data: &T) where
+    for<'a> &'a T: IntoBuf,
+{
+    let mut dst: Vec<u8> = vec![];
+    data.into_buf().copy_to(&mut dst);
+    println!("GOT: {:?}", dst);
+}
+
+pub fn main() {
+    let b = Bytes::from_slice(b"hello world");
+    dump(&b);
+    dump(&b);
+}
diff --git a/src/imp/buf/mod.rs b/src/imp/buf/mod.rs
index ca41f61..f6b7004 100644
--- a/src/imp/buf/mod.rs
+++ b/src/imp/buf/mod.rs
@@ -363,6 +363,40 @@ pub trait MutBuf {
     }
 }
 
+/*
+ *
+ * ===== IntoBuf =====
+ *
+ */
+
+/// Conversion into a `Buf`
+///
+/// Usually, `IntoBuf` is implemented on references of types and not directly
+/// on the types themselves. For example, `IntoBuf` is implemented for `&'a
+/// Vec<u8>` and not `Vec<u8>` directly.
+pub trait IntoBuf {
+    type Buf: Buf;
+
+    fn into_buf(self) -> Self::Buf;
+}
+
+impl<'a> IntoBuf for &'a [u8] {
+    type Buf = io::Cursor<&'a [u8]>;
+
+    /// Creates a buffer from a value
+    fn into_buf(self) -> Self::Buf {
+        io::Cursor::new(self)
+    }
+}
+
+impl<'a> IntoBuf for &'a Vec<u8> {
+    type Buf = io::Cursor<&'a [u8]>;
+
+    fn into_buf(self) -> Self::Buf {
+        io::Cursor::new(&self[..])
+    }
+}
+
 /*
  *
  * ===== Sink / Source =====
diff --git a/src/imp/bytes/mod.rs b/src/imp/bytes/mod.rs
index 21f51af..daf4bd4 100644
--- a/src/imp/bytes/mod.rs
+++ b/src/imp/bytes/mod.rs
@@ -2,7 +2,7 @@ pub mod rope;
 pub mod seq;
 pub mod small;
 
-use Buf;
+use {Buf, IntoBuf};
 use self::seq::Seq;
 use self::small::Small;
 use self::rope::{Rope, RopeBuf};
@@ -188,6 +188,20 @@ impl cmp::PartialEq<Bytes> for Bytes {
     }
 }
 
+impl<'a> IntoBuf for &'a Bytes {
+    type Buf = BytesBuf<'a>;
+
+    fn into_buf(self) -> Self::Buf {
+        self.buf()
+    }
+}
+
+/*
+ *
+ * ===== BytesBuf =====
+ *
+ */
+
 impl<'a> Buf for BytesBuf<'a> {
     fn remaining(&self) -> usize {
         match self.kind {
diff --git a/src/lib.rs b/src/lib.rs
index a3c92ba..6b51d45 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -10,7 +10,7 @@ mod imp;
 // TODO: delete
 mod alloc;
 
-pub use imp::buf::{Buf, MutBuf};
+pub use imp::buf::{Buf, MutBuf, IntoBuf};
 pub use imp::bytes::Bytes;
 
 pub mod buf {
-- 
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