tokio: move I/O helpers to ext traits (#1204)

Refs: #1203

13 files changed, 322 insertions, 214 deletions

diff --git a/tokio/src/io/async_read_ext.rs b/tokio/src/io/async_read_ext.rs
new file mode 100644
index 00000000..cca0906a
--- /dev/null
+++ b/tokio/src/io/async_read_ext.rs
@@ -0,0 +1,64 @@
+use crate::io::copy::{copy, Copy};
+use crate::io::read::{read, Read};
+use crate::io::read_exact::{read_exact, ReadExact};
+
+use tokio_io::{AsyncRead, AsyncWrite};
+
+/// An extension trait which adds utility methods to `AsyncRead` types.
+pub trait AsyncReadExt: AsyncRead {
+
+    /// Copy all data from `self` into the provided `AsyncWrite`.
+    ///
+    /// The returned future will copy all the bytes read from `reader` into the
+    /// `writer` specified.  This future will only complete once the `reader`
+    /// has hit EOF and all bytes have been written to and flushed from the
+    /// `writer` provided.
+    ///
+    /// On success the number of bytes is returned and the `reader` and `writer`
+    /// are consumed. On error the error is returned and the I/O objects are
+    /// consumed as well.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// unimplemented!();
+    /// ```
+    fn copy<'a, W>(&'a mut self, dst: &'a mut W) -> Copy<'a, Self, W>
+        where
+            Self: Unpin,
+            W: AsyncWrite + Unpin + ?Sized,
+    {
+        copy(self, dst)
+    }
+
+    /// Read data into the provided buffer.
+    ///
+    /// The returned future will resolve to the number of bytes read once the
+    /// read operation is completed.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// unimplemented!();
+    /// ```
+    fn read<'a>(&'a mut self, dst: &'a mut [u8]) -> Read<'a, Self>
+        where Self: Unpin,
+    {
+        read(self, dst)
+    }
+
+    /// Read exactly the amount of data needed to fill the provided buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// unimplemented!();
+    /// ```
+    fn read_exact<'a>(&'a mut self, dst: &'a mut [u8]) -> ReadExact<'a, Self>
+        where Self: Unpin,
+    {
+        read_exact(self, dst)
+    }
+}
+
+impl<R: AsyncRead + ?Sized> AsyncReadExt for R {}
diff --git a/tokio/src/io/async_write_ext.rs b/tokio/src/io/async_write_ext.rs
new file mode 100644
index 00000000..759dac99
--- /dev/null
+++ b/tokio/src/io/async_write_ext.rs
@@ -0,0 +1,24 @@
+use crate::io::write::{write, Write};
+
+use tokio_io::AsyncWrite;
+
+/// An extension trait which adds utility methods to `AsyncWrite` types.
+pub trait AsyncWriteExt: AsyncWrite {
+    /// Write the provided data into `self`.
+    ///
+    /// The returned future will resolve to the number of bytes written once the
+    /// write operation is completed.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// unimplemented!();
+    /// ````
+    fn write<'a>(&'a mut self, src: &'a [u8]) -> Write<'a, Self>
+        where Self: Unpin,
+    {
+        write(self, src)
+    }
+}
+
+impl<W: AsyncWrite + ?Sized> AsyncWriteExt for W {}
diff --git a/tokio/src/io/copy.rs b/tokio/src/io/copy.rs
index b407c193..cc8e71dd 100644
--- a/tokio/src/io/copy.rs
+++ b/tokio/src/io/copy.rs
@@ -4,23 +4,8 @@ use std::pin::Pin;
 use std::task::{Context, Poll};
 use tokio_io::{AsyncRead, AsyncWrite};
 
-macro_rules! ready {
-    ($e:expr) => {
-        match $e {
-            ::std::task::Poll::Ready(t) => t,
-            ::std::task::Poll::Pending => return ::std::task::Poll::Pending,
-        }
-    };
-}
-
-/// A future which will copy all data from a reader into a writer.
-///
-/// Created by the [`copy`] function, this future will resolve to the number of
-/// bytes copied or an error if one happens.
-///
-/// [`copy`]: fn.copy.html
 #[derive(Debug)]
-pub struct Copy<'a, R, W> {
+pub struct Copy<'a, R: ?Sized, W: ?Sized> {
     reader: &'a mut R,
     read_done: bool,
     writer: &'a mut W,
@@ -30,21 +15,10 @@ pub struct Copy<'a, R, W> {
     buf: Box<[u8]>,
 }
 
-/// Creates a future which represents copying all the bytes from one object to
-/// another.
-///
-/// The returned future will copy all the bytes read from `reader` into the
-/// `writer` specified. This future will only complete once the `reader` has hit
-/// EOF and all bytes have been written to and flushed from the `writer`
-/// provided.
-///
-/// On success the number of bytes is returned and the `reader` and `writer` are
-/// consumed. On error the error is returned and the I/O objects are consumed as
-/// well.
-pub fn copy<'a, R, W>(reader: &'a mut R, writer: &'a mut W) -> Copy<'a, R, W>
+pub(crate) fn copy<'a, R, W>(reader: &'a mut R, writer: &'a mut W) -> Copy<'a, R, W>
 where
-    R: AsyncRead + Unpin,
-    W: AsyncWrite + Unpin,
+    R: AsyncRead + Unpin + ?Sized,
+    W: AsyncWrite + Unpin + ?Sized,
 {
     Copy {
         reader,
@@ -59,8 +33,8 @@ where
 
 impl<'a, R, W> Future for Copy<'a, R, W>
 where
-    R: AsyncRead + Unpin,
-    W: AsyncWrite + Unpin,
+    R: AsyncRead + Unpin + ?Sized,
+    W: AsyncWrite + Unpin + ?Sized,
 {
     type Output = io::Result<u64>;
 
diff --git a/tokio/src/io/mod.rs b/tokio/src/io/mod.rs
index 9b3d854f..20730811 100644
--- a/tokio/src/io/mod.rs
+++ b/tokio/src/io/mod.rs
@@ -36,22 +36,21 @@
 //! [`ErrorKind`]: enum.ErrorKind.html
 //! [`Result`]: type.Result.html
 
-pub use tokio_io::{AsyncRead, AsyncWrite};
+mod async_read_ext;
+mod async_write_ext;
+mod copy;
+mod read;
+mod write;
+mod read_exact;
+
+pub use self::async_read_ext::AsyncReadExt;
+pub use self::async_write_ext::AsyncWriteExt;
 
 // standard input, output, and error
 #[cfg(feature = "fs")]
 pub use tokio_fs::{stderr, stdin, stdout, Stderr, Stdin, Stdout};
+pub use tokio_io::{AsyncRead, AsyncWrite};
 
 // Re-export io::Error so that users don't have to deal
 // with conflicts when `use`ing `futures::io` and `std::io`.
 pub use std::io::{Error, ErrorKind, Result};
-
-mod copy;
-mod read;
-mod write;
-mod read_exact;
-
-pub use self::copy::{copy, Copy};
-pub use self::read::{read, Read};
-pub use self::write::{write, Write};
-pub use self::read_exact::{read_exact, ReadExact};
diff --git a/tokio/src/io/read.rs b/tokio/src/io/read.rs
index 57137571..320c5edd 100644
--- a/tokio/src/io/read.rs
+++ b/tokio/src/io/read.rs
@@ -10,7 +10,7 @@ use tokio_io::AsyncRead;
 ///
 /// The returned future will resolve to both the I/O stream and the buffer
 /// as well as the number of bytes read once the read operation is completed.
-pub fn read<'a, R>(reader: &'a mut R, buf: &'a mut [u8]) -> Read<'a, R>
+pub(crate) fn read<'a, R>(reader: &'a mut R, buf: &'a mut [u8]) -> Read<'a, R>
 where
     R: AsyncRead + Unpin + ?Sized,
 {
diff --git a/tokio/src/io/read_exact.rs b/tokio/src/io/read_exact.rs
index e8a66a47..c8b2f884 100644
--- a/tokio/src/io/read_exact.rs
+++ b/tokio/src/io/read_exact.rs
@@ -5,23 +5,13 @@ use std::pin::Pin;
 use std::task::{Context, Poll};
 use tokio_io::AsyncRead;
 
-macro_rules! ready {
-    ($e:expr) => {
-        match $e {
-            ::std::task::Poll::Ready(t) => t,
-            ::std::task::Poll::Pending => return ::std::task::Poll::Pending,
-        }
-    };
-}
-
-
 /// A future which can be used to easily read exactly enough bytes to fill
 /// a buffer.
 ///
 /// Created by the [`read_exact`] function.
 ///
 /// [`read_exact`]: fn.read_exact.html
-pub fn read_exact<'a, A>(reader: &'a mut A, buf: &'a mut[u8]) -> ReadExact<'a, A>
+pub(crate) fn read_exact<'a, A>(reader: &'a mut A, buf: &'a mut[u8]) -> ReadExact<'a, A>
 where
     A: AsyncRead + Unpin + ?Sized
 {
diff --git a/tokio/src/io/write.rs b/tokio/src/io/write.rs
index 424f478d..2ccc61b5 100644
--- a/tokio/src/io/write.rs
+++ b/tokio/src/io/write.rs
@@ -14,7 +14,7 @@ pub struct Write<'a, W: ?Sized> {
 
 /// Tries to write some bytes from the given `buf` to the writer in an
 /// asynchronous manner, returning a future.
-pub fn write<'a, W>(writer: &'a mut W, buf: &'a [u8]) -> Write<'a, W>
+pub(crate) fn write<'a, W>(writer: &'a mut W, buf: &'a [u8]) -> Write<'a, W>
 where
     W: AsyncWrite + Unpin + ?Sized,
 {
diff --git a/tokio/src/lib.rs b/tokio/src/lib.rs
index 89f05133..d554ab00 100644
--- a/tokio/src/lib.rs
+++ b/tokio/src/lib.rs
@@ -74,6 +74,15 @@ macro_rules! if_runtime {
     )*)
 }
 
+macro_rules! ready {
+    ($e:expr) => {
+        match $e {
+            ::std::task::Poll::Ready(t) => t,
+            ::std::task::Poll::Pending => return ::std::task::Poll::Pending,
+        }
+    };
+}
+
 #[cfg(feature = "timer")]
 pub mod clock;
 #[cfg(feature = "codec")]
diff --git a/tokio/tests/io.rs b/tokio/tests/io.rs
index 5bf52d60..8224c598 100644
--- a/tokio/tests/io.rs
+++ b/tokio/tests/io.rs
@@ -8,162 +8,4 @@ use tokio::io::{AsyncRead, AsyncWrite};
 use tokio_test::assert_ready_ok;
 use tokio_test::task::MockTask;
 
-#[test]
-fn write() {
-    struct Wr(BytesMut);
 
-    impl AsyncWrite for Wr {
-        fn poll_write(
-            mut self: Pin<&mut Self>,
-            _cx: &mut Context<'_>,
-            buf: &[u8],
-        ) -> Poll<io::Result<usize>> {
-            self.0.extend(buf);
-            Ok(buf.len()).into()
-        }
-
-        fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
-            Ok(()).into()
-        }
-
-        fn poll_shutdown(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
-            Ok(()).into()
-        }
-    }
-
-    let mut task = MockTask::new();
-
-    task.enter(|cx| {
-        let mut wr = Wr(BytesMut::with_capacity(64));
-
-        let write = tokio::io::write(&mut wr, "hello world".as_bytes());
-        pin_mut!(write);
-
-        let n = assert_ready_ok!(write.poll(cx));
-        assert_eq!(n, 11);
-    });
-}
-
-#[test]
-fn read() {
-    struct Rd;
-
-    impl AsyncRead for Rd {
-        fn poll_read(
-            self: Pin<&mut Self>,
-            _cx: &mut Context<'_>,
-            buf: &mut [u8],
-        ) -> Poll<io::Result<usize>> {
-            buf[0..11].copy_from_slice(b"hello world");
-            Poll::Ready(Ok(11))
-        }
-    }
-
-    let mut buf = Box::new([0; 11]);
-    let mut task = MockTask::new();
-
-    task.enter(|cx| {
-        let mut rd = Rd;
-
-        let read = tokio::io::read(&mut rd, &mut buf[..]);
-        pin_mut!(read);
-
-        let n = assert_ready_ok!(read.poll(cx));
-        assert_eq!(n, 11);
-        assert_eq!(buf[..], b"hello world"[..]);
-    });
-}
-
-#[test]
-fn copy() {
-    struct Rd(bool);
-
-    impl AsyncRead for Rd {
-        fn poll_read(
-            mut self: Pin<&mut Self>,
-            _cx: &mut Context<'_>,
-            buf: &mut [u8],
-        ) -> Poll<io::Result<usize>> {
-            if self.0 {
-                buf[0..11].copy_from_slice(b"hello world");
-                self.0 = false;
-                Poll::Ready(Ok(11))
-            } else {
-                Poll::Ready(Ok(0))
-            }
-        }
-    }
-
-    struct Wr(BytesMut);
-
-    impl Unpin for Wr {}
-    impl AsyncWrite for Wr {
-        fn poll_write(
-            mut self: Pin<&mut Self>,
-            _cx: &mut Context<'_>,
-            buf: &[u8],
-        ) -> Poll<io::Result<usize>> {
-            self.0.extend(buf);
-            Ok(buf.len()).into()
-        }
-
-        fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
-            Ok(()).into()
-        }
-
-        fn poll_shutdown(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
-            Ok(()).into()
-        }
-    }
-
-    let buf = BytesMut::with_capacity(64);
-    let mut task = MockTask::new();
-
-    task.enter(|cx| {
-        let mut rd = Rd(true);
-        let mut wr = Wr(buf);
-
-        let copy = tokio::io::copy(&mut rd, &mut wr);
-        pin_mut!(copy);
-
-        let n = assert_ready_ok!(copy.poll(cx));
-
-        assert_eq!(n, 11);
-        assert_eq!(wr.0[..], b"hello world"[..]);
-    });
-}
-
-#[test]
-fn read_exact() {
-    struct Rd {
-        val: &'static [u8; 11],
-    }
-
-    impl AsyncRead for Rd {
-        fn poll_read(
-            mut self: Pin<&mut Self>,
-            _cx: &mut Context<'_>,
-            buf: &mut [u8]
-        ) -> Poll<io::Result<usize>> {
-            let me = &mut *self;
-            let len = buf.len();
-
-            buf[..].copy_from_slice(&me.val[..len]);
-            Poll::Ready(Ok(buf.len()))
-        }
-    }
-
-    let mut buf = Box::new([0; 8]);
-    let mut task = MockTask::new();
-
-    task.enter(|cx| {
-        let mut rd = Rd { val: b"hello world" };
-
-        let read = tokio::io::read_exact(&mut rd, &mut buf[..]);
-        pin_mut!(read);
-
-        let n = assert_ready_ok!(read.poll(cx));
-        assert_eq!(n, 8);
-        assert_eq!(buf[..], b"hello wo"[..]);
-    });
-}
diff --git a/tokio/tests/io_copy.rs b/tokio/tests/io_copy.rs
new file mode 100644
index 00000000..ee972681
--- /dev/null
+++ b/tokio/tests/io_copy.rs
@@ -0,0 +1,71 @@
+#![deny(warnings, rust_2018_idioms)]
+
+use tokio::io::{AsyncRead, AsyncWrite, AsyncReadExt};
+use tokio_test::assert_ready_ok;
+use tokio_test::task::MockTask;
+
+use bytes::BytesMut;
+use pin_utils::pin_mut;
+use std::future::Future;
+use std::io;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+#[test]
+fn copy() {
+    struct Rd(bool);
+
+    impl AsyncRead for Rd {
+        fn poll_read(
+            mut self: Pin<&mut Self>,
+            _cx: &mut Context<'_>,
+            buf: &mut [u8],
+        ) -> Poll<io::Result<usize>> {
+            if self.0 {
+                buf[0..11].copy_from_slice(b"hello world");
+                self.0 = false;
+                Poll::Ready(Ok(11))
+            } else {
+                Poll::Ready(Ok(0))
+            }
+        }
+    }
+
+    struct Wr(BytesMut);
+
+    impl Unpin for Wr {}
+    impl AsyncWrite for Wr {
+        fn poll_write(
+            mut self: Pin<&mut Self>,
+            _cx: &mut Context<'_>,
+            buf: &[u8],
+        ) -> Poll<io::Result<usize>> {
+            self.0.extend(buf);
+            Ok(buf.len()).into()
+        }
+
+        fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+            Ok(()).into()
+        }
+
+        fn poll_shutdown(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+            Ok(()).into()
+        }
+    }
+
+    let buf = BytesMut::with_capacity(64);
+    let mut task = MockTask::new();
+
+    task.enter(|cx| {
+        let mut rd = Rd(true);
+        let mut wr = Wr(buf);
+
+        let copy = rd.copy(&mut wr);
+        pin_mut!(copy);
+
+        let n = assert_ready_ok!(copy.poll(cx));
+
+        assert_eq!(n, 11);
+        assert_eq!(wr.0[..], b"hello world"[..]);
+    });
+}
diff --git a/tokio/tests/io_read.rs b/tokio/tests/io_read.rs
new file mode 100644
index 00000000..8544a6c6
--- /dev/null
+++ b/tokio/tests/io_read.rs
@@ -0,0 +1,41 @@
+#![deny(warnings, rust_2018_idioms)]
+
+use tokio::io::{AsyncRead, AsyncReadExt};
+use tokio_test::assert_ready_ok;
+use tokio_test::task::MockTask;
+
+use pin_utils::pin_mut;
+use std::future::Future;
+use std::io;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+#[test]
+fn read() {
+    struct Rd;
+
+    impl AsyncRead for Rd {
+        fn poll_read(
+            self: Pin<&mut Self>,
+            _cx: &mut Context<'_>,
+            buf: &mut [u8],
+        ) -> Poll<io::Result<usize>> {
+            buf[0..11].copy_from_slice(b"hello world");
+            Poll::Ready(Ok(11))
+        }
+    }
+
+    let mut buf = Box::new([0; 11]);
+    let mut task = MockTask::new();
+
+    task.enter(|cx| {
+        let mut rd = Rd;
+
+        let read = rd.read(&mut buf[..]);
+        pin_mut!(read);
+
+        let n = assert_ready_ok!(read.poll(cx));
+        assert_eq!(n, 11);
+        assert_eq!(buf[..], b"hello world"[..]);
+    });
+}
diff --git a/tokio/tests/io_read_exact.rs b/tokio/tests/io_read_exact.rs
new file mode 100644
index 00000000..94e35514
--- /dev/null
+++ b/tokio/tests/io_read_exact.rs
@@ -0,0 +1,46 @@
+#![deny(warnings, rust_2018_idioms)]
+
+use tokio::io::{AsyncRead, AsyncReadExt};
+use tokio_test::assert_ready_ok;
+use tokio_test::task::MockTask;
+
+use pin_utils::pin_mut;
+use std::future::Future;
+use std::io;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+#[test]
+fn read_exact() {
+    struct Rd {
+        val: &'static [u8; 11],
+    }
+
+    impl AsyncRead for Rd {
+        fn poll_read(
+            mut self: Pin<&mut Self>,
+            _cx: &mut Context<'_>,
+            buf: &mut [u8]
+        ) -> Poll<io::Result<usize>> {
+            let me = &mut *self;
+            let len = buf.len();
+
+            buf[..].copy_from_slice(&me.val[..len]);
+            Poll::Ready(Ok(buf.len()))
+        }
+    }
+
+    let mut buf = Box::new([0; 8]);
+    let mut task = MockTask::new();
+
+    task.enter(|cx| {
+        let mut rd = Rd { val: b"hello world" };
+
+        let read = rd.read_exact(&mut buf[..]);
+        pin_mut!(read);
+
+        let n = assert_ready_ok!(read.poll(cx));
+        assert_eq!(n, 8);
+        assert_eq!(buf[..], b"hello wo"[..]);
+    });
+}
diff --git a/tokio/tests/io_write.rs b/tokio/tests/io_write.rs
new file mode 100644
index 00000000..7d80ca55
--- /dev/null
+++ b/tokio/tests/io_write.rs
@@ -0,0 +1,48 @@
+#![deny(warnings, rust_2018_idioms)]
+
+use tokio::io::{AsyncWrite, AsyncWriteExt};
+use tokio_test::assert_ready_ok;
+use tokio_test::task::MockTask;
+
+use bytes::BytesMut;
+use pin_utils::pin_mut;
+use std::future::Future;
+use std::io;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+#[test]
+fn write() {
+    struct Wr(BytesMut);
+
+    impl AsyncWrite for Wr {
+        fn poll_write(
+            mut self: Pin<&mut Self>,
+            _cx: &mut Context<'_>,
+            buf: &[u8],
+        ) -> Poll<io::Result<usize>> {
+            self.0.extend(buf);
+            Ok(buf.len()).into()
+        }
+
+        fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+            Ok(()).into()
+        }
+
+        fn poll_shutdown(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+            Ok(()).into()
+        }
+    }
+
+    let mut task = MockTask::new();
+
+    task.enter(|cx| {
+        let mut wr = Wr(BytesMut::with_capacity(64));
+
+        let write = wr.write(b"hello world");
+        pin_mut!(write);
+
+        let n = assert_ready_ok!(write.poll(cx));
+        assert_eq!(n, 11);
+    });
+}