From 49f37ac424d7df1f8ee1989d8f3b5ceb6b6a9ea0 Mon Sep 17 00:00:00 2001
From: Haibo Huang <hhb@google.com>
Date: Mon, 11 Jan 2021 19:30:56 -0800
Subject: Upgrade rust/crates/bytes to 1.0.1

Test: make
Change-Id: Ie9751d0251a3844858395badc8546303dcddeb24
---
 src/buf/chain.rs | 222 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 222 insertions(+)
 create mode 100644 src/buf/chain.rs

(limited to 'src/buf/chain.rs')

diff --git a/src/buf/chain.rs b/src/buf/chain.rs
new file mode 100644
index 0000000..d68bc2d
--- /dev/null
+++ b/src/buf/chain.rs
@@ -0,0 +1,222 @@
+use crate::buf::{IntoIter, UninitSlice};
+use crate::{Buf, BufMut};
+
+#[cfg(feature = "std")]
+use std::io::IoSlice;
+
+/// A `Chain` sequences two buffers.
+///
+/// `Chain` is an adapter that links two underlying buffers and provides a
+/// continuous view across both buffers. It is able to sequence either immutable
+/// buffers ([`Buf`] values) or mutable buffers ([`BufMut`] values).
+///
+/// This struct is generally created by calling [`Buf::chain`]. Please see that
+/// function's documentation for more detail.
+///
+/// # Examples
+///
+/// ```
+/// use bytes::{Bytes, Buf};
+///
+/// let mut buf = (&b"hello "[..])
+///     .chain(&b"world"[..]);
+///
+/// let full: Bytes = buf.copy_to_bytes(11);
+/// assert_eq!(full[..], b"hello world"[..]);
+/// ```
+///
+/// [`Buf::chain`]: trait.Buf.html#method.chain
+/// [`Buf`]: trait.Buf.html
+/// [`BufMut`]: trait.BufMut.html
+#[derive(Debug)]
+pub struct Chain<T, U> {
+    a: T,
+    b: U,
+}
+
+impl<T, U> Chain<T, U> {
+    /// Creates a new `Chain` sequencing the provided values.
+    pub(crate) fn new(a: T, b: U) -> Chain<T, U> {
+        Chain { a, b }
+    }
+
+    /// Gets a reference to the first underlying `Buf`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let buf = (&b"hello"[..])
+    ///     .chain(&b"world"[..]);
+    ///
+    /// assert_eq!(buf.first_ref()[..], b"hello"[..]);
+    /// ```
+    pub fn first_ref(&self) -> &T {
+        &self.a
+    }
+
+    /// Gets a mutable reference to the first underlying `Buf`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let mut buf = (&b"hello"[..])
+    ///     .chain(&b"world"[..]);
+    ///
+    /// buf.first_mut().advance(1);
+    ///
+    /// let full = buf.copy_to_bytes(9);
+    /// assert_eq!(full, b"elloworld"[..]);
+    /// ```
+    pub fn first_mut(&mut self) -> &mut T {
+        &mut self.a
+    }
+
+    /// Gets a reference to the last underlying `Buf`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let buf = (&b"hello"[..])
+    ///     .chain(&b"world"[..]);
+    ///
+    /// assert_eq!(buf.last_ref()[..], b"world"[..]);
+    /// ```
+    pub fn last_ref(&self) -> &U {
+        &self.b
+    }
+
+    /// Gets a mutable reference to the last underlying `Buf`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let mut buf = (&b"hello "[..])
+    ///     .chain(&b"world"[..]);
+    ///
+    /// buf.last_mut().advance(1);
+    ///
+    /// let full = buf.copy_to_bytes(10);
+    /// assert_eq!(full, b"hello orld"[..]);
+    /// ```
+    pub fn last_mut(&mut self) -> &mut U {
+        &mut self.b
+    }
+
+    /// Consumes this `Chain`, returning the underlying values.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let chain = (&b"hello"[..])
+    ///     .chain(&b"world"[..]);
+    ///
+    /// let (first, last) = chain.into_inner();
+    /// assert_eq!(first[..], b"hello"[..]);
+    /// assert_eq!(last[..], b"world"[..]);
+    /// ```
+    pub fn into_inner(self) -> (T, U) {
+        (self.a, self.b)
+    }
+}
+
+impl<T, U> Buf for Chain<T, U>
+where
+    T: Buf,
+    U: Buf,
+{
+    fn remaining(&self) -> usize {
+        self.a.remaining() + self.b.remaining()
+    }
+
+    fn chunk(&self) -> &[u8] {
+        if self.a.has_remaining() {
+            self.a.chunk()
+        } else {
+            self.b.chunk()
+        }
+    }
+
+    fn advance(&mut self, mut cnt: usize) {
+        let a_rem = self.a.remaining();
+
+        if a_rem != 0 {
+            if a_rem >= cnt {
+                self.a.advance(cnt);
+                return;
+            }
+
+            // Consume what is left of a
+            self.a.advance(a_rem);
+
+            cnt -= a_rem;
+        }
+
+        self.b.advance(cnt);
+    }
+
+    #[cfg(feature = "std")]
+    fn chunks_vectored<'a>(&'a self, dst: &mut [IoSlice<'a>]) -> usize {
+        let mut n = self.a.chunks_vectored(dst);
+        n += self.b.chunks_vectored(&mut dst[n..]);
+        n
+    }
+}
+
+unsafe impl<T, U> BufMut for Chain<T, U>
+where
+    T: BufMut,
+    U: BufMut,
+{
+    fn remaining_mut(&self) -> usize {
+        self.a.remaining_mut() + self.b.remaining_mut()
+    }
+
+    fn chunk_mut(&mut self) -> &mut UninitSlice {
+        if self.a.has_remaining_mut() {
+            self.a.chunk_mut()
+        } else {
+            self.b.chunk_mut()
+        }
+    }
+
+    unsafe fn advance_mut(&mut self, mut cnt: usize) {
+        let a_rem = self.a.remaining_mut();
+
+        if a_rem != 0 {
+            if a_rem >= cnt {
+                self.a.advance_mut(cnt);
+                return;
+            }
+
+            // Consume what is left of a
+            self.a.advance_mut(a_rem);
+
+            cnt -= a_rem;
+        }
+
+        self.b.advance_mut(cnt);
+    }
+}
+
+impl<T, U> IntoIterator for Chain<T, U>
+where
+    T: Buf,
+    U: Buf,
+{
+    type Item = u8;
+    type IntoIter = IntoIter<Chain<T, U>>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        IntoIter::new(self)
+    }
+}
-- 
cgit v1.2.3