Change copy_into/copy_buf_into to free functions for consistency with…

… the standard library

futures-util/src/io/copy.rs

@@ -0,0 +1,63 @@
+use futures_core::future::Future;
+use futures_core::task::{Context, Poll};
+use futures_io::{AsyncRead, AsyncWrite};
+use std::io;
+use std::pin::Pin;
+use super::{BufReader, copy_buf, CopyBuf};
+use pin_utils::unsafe_pinned;
+
+/// Creates a future which copies all the bytes from one object to another.
+///
+/// The returned future will copy all the bytes read from this `AsyncRead` 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.
+///
+/// # Examples
+///
+/// ```
+/// # futures::executor::block_on(async {
+/// use futures::io::{self, AsyncWriteExt, Cursor};
+///
+/// let reader = Cursor::new([1, 2, 3, 4]);
+/// let mut writer = Cursor::new(vec![0u8; 5]);
+///
+/// let bytes = io::copy(reader, &mut writer).await?;
+/// writer.close().await?;
+///
+/// assert_eq!(bytes, 4);
+/// assert_eq!(writer.into_inner(), [1, 2, 3, 4, 0]);
+/// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap();
+/// ```
+pub fn copy<R, W>(reader: R, writer: &mut W) -> Copy<'_, R, W>
+where
+    R: AsyncRead,
+    W: AsyncWrite + Unpin + ?Sized,
+{
+    Copy {
+        inner: copy_buf(BufReader::new(reader), writer),
+    }
+}
+
+/// Future for the [`copy()`] function.
+#[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
+pub struct Copy<'a, R, W: ?Sized> {
+    inner: CopyBuf<'a, BufReader<R>, W>,
+}
+
+impl<'a, R: AsyncRead, W: ?Sized> Unpin for Copy<'a, R, W> where CopyBuf<'a, BufReader<R>, W>: Unpin {}
+
+impl<'a, R: AsyncRead, W: ?Sized> Copy<'a, R, W> {
+    unsafe_pinned!(inner: CopyBuf<'a, BufReader<R>, W>);
+}
+
+impl<R: AsyncRead, W: AsyncWrite + Unpin + ?Sized> Future for Copy<'_, R, W> {
+    type Output = io::Result<u64>;
+
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        self.inner().poll(cx)
+    }
+}

futures-util/src/io/copy_buf_into.rs → futures-util/src/io/copy_buf.rs

@@ -4,28 +4,55 @@ use futures_io::{AsyncBufRead, AsyncWrite};
 use std::io;
 use std::pin::Pin;
 
-/// Future for the [`copy_buf_into`](super::AsyncBufReadExt::copy_buf_into) method.
+/// Creates a future which copies all the bytes from one object to another.
+///
+/// The returned future will copy all the bytes read from this `AsyncBufRead` 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.
+///
+/// # Examples
+///
+/// ```
+/// # futures::executor::block_on(async {
+/// use futures::io::{self, AsyncWriteExt, Cursor};
+///
+/// let reader = Cursor::new([1, 2, 3, 4]);
+/// let mut writer = Cursor::new(vec![0u8; 5]);
+///
+/// let bytes = io::copy_buf(reader, &mut writer).await?;
+/// writer.close().await?;
+///
+/// assert_eq!(bytes, 4);
+/// assert_eq!(writer.into_inner(), [1, 2, 3, 4, 0]);
+/// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap();
+/// ```
+pub fn copy_buf<R, W>(reader: R, writer: &mut W) -> CopyBuf<'_, R, W>
+where
+    R: AsyncBufRead,
+    W: AsyncWrite + Unpin + ?Sized,
+{
+    CopyBuf {
+        reader,
+        writer,
+        amt: 0,
+    }
+}
+
+/// Future for the [`copy_buf()`] function.
 #[derive(Debug)]
 #[must_use = "futures do nothing unless you `.await` or poll them"]
-pub struct CopyBufInto<'a, R, W: ?Sized> {
+pub struct CopyBuf<'a, R, W: ?Sized> {
     reader: R,
     writer: &'a mut W,
     amt: u64,
 }
 
-impl<R: Unpin, W: ?Sized> Unpin for CopyBufInto<'_, R, W> {}
-
-impl<R, W: ?Sized> CopyBufInto<'_, R, W> {
-    pub(super) fn new(reader: R, writer: &mut W) -> CopyBufInto<'_, R, W> {
-        CopyBufInto {
-            reader,
-            writer,
-            amt: 0,
-        }
-    }
-}
+impl<R: Unpin, W: ?Sized> Unpin for CopyBuf<'_, R, W> {}
 
-impl<R, W: Unpin + ?Sized> CopyBufInto<'_, R, W> {
+impl<R, W: Unpin + ?Sized> CopyBuf<'_, R, W> {
     fn project(self: Pin<&mut Self>) -> (Pin<&mut R>, Pin<&mut W>, &mut u64) {
         unsafe {
             let this = self.get_unchecked_mut();
@@ -34,7 +61,7 @@ impl<R, W: Unpin + ?Sized> CopyBufInto<'_, R, W> {
     }
 }
 
-impl<R, W> Future for CopyBufInto<'_, R, W>
+impl<R, W> Future for CopyBuf<'_, R, W>
     where R: AsyncBufRead,
           W: AsyncWrite + Unpin + ?Sized,
 {

futures-util/src/io/mod.rs

@@ -53,11 +53,11 @@ pub use self::chain::Chain;
 mod close;
 pub use self::close::Close;
 
-mod copy_into;
-pub use self::copy_into::CopyInto;
+mod copy;
+pub use self::copy::{copy, Copy};
 
-mod copy_buf_into;
-pub use self::copy_buf_into::CopyBufInto;
+mod copy_buf;
+pub use self::copy_buf::{copy_buf, CopyBuf};
 
 mod cursor;
 pub use self::cursor::Cursor;
@@ -157,39 +157,6 @@ pub trait AsyncReadExt: AsyncRead {
         Chain::new(self, next)
     }
 
-    /// Creates a future which copies all the bytes from one object to another.
-    ///
-    /// The returned future will copy all the bytes read from this `AsyncRead` 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.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// # futures::executor::block_on(async {
-    /// use futures::io::{AsyncReadExt, AsyncWriteExt, Cursor};
-    ///
-    /// let reader = Cursor::new([1, 2, 3, 4]);
-    /// let mut writer = Cursor::new(vec![0u8; 5]);
-    ///
-    /// let bytes = reader.copy_into(&mut writer).await?;
-    /// writer.close().await?;
-    ///
-    /// assert_eq!(bytes, 4);
-    /// assert_eq!(writer.into_inner(), [1, 2, 3, 4, 0]);
-    /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap();
-    /// ```
-    fn copy_into<W>(self, writer: &mut W) -> CopyInto<'_, Self, W>
-    where
-        Self: Sized,
-        W: AsyncWrite + Unpin + ?Sized,
-    {
-        CopyInto::new(self, writer)
-    }
-
     /// Tries to read some bytes directly into the given `buf` in asynchronous
     /// manner, returning a future type.
     ///
@@ -342,7 +309,7 @@ pub trait AsyncReadExt: AsyncRead {
     ///
     /// ```
     /// # futures::executor::block_on(async {
-    /// use futures::io::{AsyncReadExt, Cursor};
+    /// use futures::io::{self, AsyncReadExt, Cursor};
     ///
     /// // Note that for `Cursor` the read and write halves share a single
     /// // seek position. This may or may not be true for other types that
@@ -354,8 +321,8 @@ pub trait AsyncReadExt: AsyncRead {
     ///
     /// {
     ///     let (buffer_reader, mut buffer_writer) = (&mut buffer).split();
-    ///     reader.copy_into(&mut buffer_writer).await?;
-    ///     buffer_reader.copy_into(&mut writer).await?;
+    ///     io::copy(reader, &mut buffer_writer).await?;
+    ///     io::copy(buffer_reader, &mut writer).await?;
     /// }
     ///
     /// assert_eq!(buffer.into_inner(), [1, 2, 3, 4, 5, 6, 7, 8]);
@@ -558,39 +525,6 @@ impl<S: AsyncSeek + ?Sized> AsyncSeekExt for S {}
 
 /// An extension trait which adds utility methods to `AsyncBufRead` types.
 pub trait AsyncBufReadExt: AsyncBufRead {
-    /// Creates a future which copies all the bytes from one object to another.
-    ///
-    /// The returned future will copy all the bytes read from this `AsyncBufRead` 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.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// # futures::executor::block_on(async {
-    /// use futures::io::{AsyncBufReadExt, AsyncWriteExt, Cursor};
-    ///
-    /// let reader = Cursor::new([1, 2, 3, 4]);
-    /// let mut writer = Cursor::new(vec![0u8; 5]);
-    ///
-    /// let bytes = reader.copy_buf_into(&mut writer).await?;
-    /// writer.close().await?;
-    ///
-    /// assert_eq!(bytes, 4);
-    /// assert_eq!(writer.into_inner(), [1, 2, 3, 4, 0]);
-    /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap();
-    /// ```
-    fn copy_buf_into<W>(self, writer: &mut W) -> CopyBufInto<'_, Self, W>
-    where
-        Self: Sized,
-        W: AsyncWrite + Unpin + ?Sized,
-    {
-        CopyBufInto::new(self, writer)
-    }
-
     /// Creates a future which will read all the bytes associated with this I/O
     /// object into `buf` until the delimiter `byte` or EOF is reached.
     /// This method is the async equivalent to [`BufRead::read_until`](std::io::BufRead::read_until).

futures/src/lib.rs

@@ -271,7 +271,7 @@ pub mod io {
 
     pub use futures_util::io::{
         AsyncReadExt, AsyncWriteExt, AsyncSeekExt, AsyncBufReadExt, AllowStdIo,
-        BufReader, BufWriter, Cursor, Chain, Close, CopyInto, CopyBufInto,
+        BufReader, BufWriter, Cursor, Chain, Close, copy, Copy, copy_buf, CopyBuf,
         empty, Empty, Flush, IntoSink, Lines, Read, ReadExact, ReadHalf,
         ReadLine, ReadToEnd, ReadToString, ReadUntil, ReadVectored, repeat,
         Repeat, Seek, sink, Sink, Take, Window, Write, WriteAll, WriteHalf,