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-rw-r--r--third_party/rust/futures-util/src/io/cursor.rs240
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diff --git a/third_party/rust/futures-util/src/io/cursor.rs b/third_party/rust/futures-util/src/io/cursor.rs
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+use futures_core::task::{Context, Poll};
+#[cfg(feature = "read_initializer")]
+use futures_io::Initializer;
+use futures_io::{AsyncBufRead, AsyncRead, AsyncSeek, AsyncWrite, IoSlice, IoSliceMut, SeekFrom};
+use std::io;
+use std::pin::Pin;
+
+/// A `Cursor` wraps an in-memory buffer and provides it with a
+/// [`AsyncSeek`] implementation.
+///
+/// `Cursor`s are used with in-memory buffers, anything implementing
+/// `AsRef<[u8]>`, to allow them to implement [`AsyncRead`] and/or [`AsyncWrite`],
+/// allowing these buffers to be used anywhere you might use a reader or writer
+/// that does actual I/O.
+///
+/// This library implements some I/O traits on various types which
+/// are commonly used as a buffer, like `Cursor<`[`Vec`]`<u8>>` and
+/// `Cursor<`[`&[u8]`][bytes]`>`.
+///
+/// [`AsyncSeek`]: trait.AsyncSeek.html
+/// [`AsyncRead`]: trait.AsyncRead.html
+/// [`AsyncWrite`]: trait.AsyncWrite.html
+/// [bytes]: https://doc.rust-lang.org/std/primitive.slice.html
+#[derive(Clone, Debug, Default)]
+pub struct Cursor<T> {
+ inner: io::Cursor<T>,
+}
+
+impl<T> Cursor<T> {
+ /// Creates a new cursor wrapping the provided underlying in-memory buffer.
+ ///
+ /// Cursor initial position is `0` even if underlying buffer (e.g., `Vec`)
+ /// is not empty. So writing to cursor starts with overwriting `Vec`
+ /// content, not with appending to it.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use futures::io::Cursor;
+ ///
+ /// let buff = Cursor::new(Vec::new());
+ /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+ /// # force_inference(&buff);
+ /// ```
+ pub fn new(inner: T) -> Self {
+ Self { inner: io::Cursor::new(inner) }
+ }
+
+ /// Consumes this cursor, returning the underlying value.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use futures::io::Cursor;
+ ///
+ /// let buff = Cursor::new(Vec::new());
+ /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+ /// # force_inference(&buff);
+ ///
+ /// let vec = buff.into_inner();
+ /// ```
+ pub fn into_inner(self) -> T {
+ self.inner.into_inner()
+ }
+
+ /// Gets a reference to the underlying value in this cursor.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use futures::io::Cursor;
+ ///
+ /// let buff = Cursor::new(Vec::new());
+ /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+ /// # force_inference(&buff);
+ ///
+ /// let reference = buff.get_ref();
+ /// ```
+ pub fn get_ref(&self) -> &T {
+ self.inner.get_ref()
+ }
+
+ /// Gets a mutable reference to the underlying value in this cursor.
+ ///
+ /// Care should be taken to avoid modifying the internal I/O state of the
+ /// underlying value as it may corrupt this cursor's position.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use futures::io::Cursor;
+ ///
+ /// let mut buff = Cursor::new(Vec::new());
+ /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+ /// # force_inference(&buff);
+ ///
+ /// let reference = buff.get_mut();
+ /// ```
+ pub fn get_mut(&mut self) -> &mut T {
+ self.inner.get_mut()
+ }
+
+ /// Returns the current position of this cursor.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// # futures::executor::block_on(async {
+ /// use futures::io::{AsyncSeekExt, Cursor, SeekFrom};
+ ///
+ /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+ ///
+ /// assert_eq!(buff.position(), 0);
+ ///
+ /// buff.seek(SeekFrom::Current(2)).await?;
+ /// assert_eq!(buff.position(), 2);
+ ///
+ /// buff.seek(SeekFrom::Current(-1)).await?;
+ /// assert_eq!(buff.position(), 1);
+ /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap();
+ /// ```
+ pub fn position(&self) -> u64 {
+ self.inner.position()
+ }
+
+ /// Sets the position of this cursor.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use futures::io::Cursor;
+ ///
+ /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+ ///
+ /// assert_eq!(buff.position(), 0);
+ ///
+ /// buff.set_position(2);
+ /// assert_eq!(buff.position(), 2);
+ ///
+ /// buff.set_position(4);
+ /// assert_eq!(buff.position(), 4);
+ /// ```
+ pub fn set_position(&mut self, pos: u64) {
+ self.inner.set_position(pos)
+ }
+}
+
+impl<T> AsyncSeek for Cursor<T>
+where
+ T: AsRef<[u8]> + Unpin,
+{
+ fn poll_seek(
+ mut self: Pin<&mut Self>,
+ _: &mut Context<'_>,
+ pos: SeekFrom,
+ ) -> Poll<io::Result<u64>> {
+ Poll::Ready(io::Seek::seek(&mut self.inner, pos))
+ }
+}
+
+impl<T: AsRef<[u8]> + Unpin> AsyncRead for Cursor<T> {
+ #[cfg(feature = "read_initializer")]
+ #[inline]
+ unsafe fn initializer(&self) -> Initializer {
+ io::Read::initializer(&self.inner)
+ }
+
+ fn poll_read(
+ mut self: Pin<&mut Self>,
+ _cx: &mut Context<'_>,
+ buf: &mut [u8],
+ ) -> Poll<io::Result<usize>> {
+ Poll::Ready(io::Read::read(&mut self.inner, buf))
+ }
+
+ fn poll_read_vectored(
+ mut self: Pin<&mut Self>,
+ _: &mut Context<'_>,
+ bufs: &mut [IoSliceMut<'_>],
+ ) -> Poll<io::Result<usize>> {
+ Poll::Ready(io::Read::read_vectored(&mut self.inner, bufs))
+ }
+}
+
+impl<T> AsyncBufRead for Cursor<T>
+where
+ T: AsRef<[u8]> + Unpin,
+{
+ fn poll_fill_buf(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<&[u8]>> {
+ Poll::Ready(io::BufRead::fill_buf(&mut self.get_mut().inner))
+ }
+
+ fn consume(mut self: Pin<&mut Self>, amt: usize) {
+ io::BufRead::consume(&mut self.inner, amt)
+ }
+}
+
+macro_rules! delegate_async_write_to_stdio {
+ () => {
+ fn poll_write(
+ mut self: Pin<&mut Self>,
+ _: &mut Context<'_>,
+ buf: &[u8],
+ ) -> Poll<io::Result<usize>> {
+ Poll::Ready(io::Write::write(&mut self.inner, buf))
+ }
+
+ fn poll_write_vectored(
+ mut self: Pin<&mut Self>,
+ _: &mut Context<'_>,
+ bufs: &[IoSlice<'_>],
+ ) -> Poll<io::Result<usize>> {
+ Poll::Ready(io::Write::write_vectored(&mut self.inner, bufs))
+ }
+
+ fn poll_flush(mut self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<()>> {
+ Poll::Ready(io::Write::flush(&mut self.inner))
+ }
+
+ fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+ self.poll_flush(cx)
+ }
+ };
+}
+
+impl AsyncWrite for Cursor<&mut [u8]> {
+ delegate_async_write_to_stdio!();
+}
+
+impl AsyncWrite for Cursor<&mut Vec<u8>> {
+ delegate_async_write_to_stdio!();
+}
+
+impl AsyncWrite for Cursor<Vec<u8>> {
+ delegate_async_write_to_stdio!();
+}
+
+impl AsyncWrite for Cursor<Box<[u8]>> {
+ delegate_async_write_to_stdio!();
+}
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