Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 100 insertions, 0 deletions

diff --git a/third_party/rust/tokio/src/io/util/empty.rs b/third_party/rust/tokio/src/io/util/empty.rs
new file mode 100644
index 0000000000..77db60e40b
--- /dev/null
+++ b/third_party/rust/tokio/src/io/util/empty.rs
@@ -0,0 +1,100 @@
+use crate::io::{AsyncBufRead, AsyncRead, ReadBuf};
+
+use std::fmt;
+use std::io;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+cfg_io_util! {
+    /// An async reader which is always at EOF.
+    ///
+    /// This struct is generally created by calling [`empty`]. Please see
+    /// the documentation of [`empty()`][`empty`] for more details.
+    ///
+    /// This is an asynchronous version of [`std::io::empty`][std].
+    ///
+    /// [`empty`]: fn@empty
+    /// [std]: std::io::empty
+    pub struct Empty {
+        _p: (),
+    }
+
+    /// Creates a new empty async reader.
+    ///
+    /// All reads from the returned reader will return `Poll::Ready(Ok(0))`.
+    ///
+    /// This is an asynchronous version of [`std::io::empty`][std].
+    ///
+    /// [std]: std::io::empty
+    ///
+    /// # Examples
+    ///
+    /// A slightly sad example of not reading anything into a buffer:
+    ///
+    /// ```
+    /// use tokio::io::{self, AsyncReadExt};
+    ///
+    /// #[tokio::main]
+    /// async fn main() {
+    ///     let mut buffer = String::new();
+    ///     io::empty().read_to_string(&mut buffer).await.unwrap();
+    ///     assert!(buffer.is_empty());
+    /// }
+    /// ```
+    pub fn empty() -> Empty {
+        Empty { _p: () }
+    }
+}
+
+impl AsyncRead for Empty {
+    #[inline]
+    fn poll_read(
+        self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+        _: &mut ReadBuf<'_>,
+    ) -> Poll<io::Result<()>> {
+        ready!(poll_proceed_and_make_progress(cx));
+        Poll::Ready(Ok(()))
+    }
+}
+
+impl AsyncBufRead for Empty {
+    #[inline]
+    fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<&[u8]>> {
+        ready!(poll_proceed_and_make_progress(cx));
+        Poll::Ready(Ok(&[]))
+    }
+
+    #[inline]
+    fn consume(self: Pin<&mut Self>, _: usize) {}
+}
+
+impl fmt::Debug for Empty {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.pad("Empty { .. }")
+    }
+}
+
+cfg_coop! {
+    fn poll_proceed_and_make_progress(cx: &mut Context<'_>) -> Poll<()> {
+        let coop = ready!(crate::coop::poll_proceed(cx));
+        coop.made_progress();
+        Poll::Ready(())
+    }
+}
+
+cfg_not_coop! {
+    fn poll_proceed_and_make_progress(_: &mut Context<'_>) -> Poll<()> {
+        Poll::Ready(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn assert_unpin() {
+        crate::is_unpin::<Empty>();
+    }
+}