chore: prepare bytes v1.11.0 (#804)

Signed-off-by: discord9 <[email protected]>

CHANGELOG.md

@@ -1,3 +1,22 @@
+# 1.11.0 (November 14th, 2025)
+
+- Bump MSRV to 1.57 (#788)
+
+### Fixed
+
+- fix: `BytesMut` only reuse if src has remaining (#803)
+- Specialize `BytesMut::put::<Bytes>` (#793)
+- Reserve capacity in `BytesMut::put` (#794)
+- Change `BytesMut::remaining_mut` to use `isize::MAX` instead of `usize::MAX` (#795)
+
+### Internal changes
+
+- Guarantee address in `slice()` for empty slices. (#780)
+- Rename `Vtable::to_*` -> `Vtable::into_*` (#776)
+- Fix latest clippy warnings (#787)
+- Ignore `BytesMut::freeze` doctest on wasm (#790)
+- Move `drop_fn` of `from_owner` into vtable (#801)
+
 # 1.10.1 (March 5th, 2025)
 
 ### Fixed

Cargo.toml

@@ -4,9 +4,9 @@ name = "bytes"
 # When releasing to crates.io:
 # - Update CHANGELOG.md.
 # - Create "v1.x.y" git tag.
-version = "1.10.1"
-edition = "2018"
-rust-version = "1.39"
+version = "1.11.0"
+edition = "2021"
+rust-version = "1.57"
 license = "MIT"
 authors = [
     "Carl Lerche <[email protected]>",

clippy.toml

@@ -1 +1 @@
-msrv = "1.39"
+msrv = "1.57"

src/buf/buf_mut.rs

@@ -3,7 +3,7 @@ use crate::buf::{limit, Chain, Limit, UninitSlice};
 use crate::buf::{writer, Writer};
 use crate::{panic_advance, panic_does_not_fit, TryGetError};
 
-use core::{mem, ptr, usize};
+use core::{mem, ptr};
 
 use alloc::{boxed::Box, vec::Vec};
 
@@ -1503,7 +1503,7 @@ unsafe impl BufMut for &mut [u8] {
         }
 
         // Lifetime dance taken from `impl Write for &mut [u8]`.
-        let (_, b) = core::mem::replace(self, &mut []).split_at_mut(cnt);
+        let (_, b) = core::mem::take(self).split_at_mut(cnt);
         *self = b;
     }
 
@@ -1559,7 +1559,7 @@ unsafe impl BufMut for &mut [core::mem::MaybeUninit<u8>] {
         }
 
         // Lifetime dance taken from `impl Write for &mut [u8]`.
-        let (_, b) = core::mem::replace(self, &mut []).split_at_mut(cnt);
+        let (_, b) = core::mem::take(self).split_at_mut(cnt);
         *self = b;
     }
 
@@ -1600,7 +1600,7 @@ unsafe impl BufMut for Vec<u8> {
     #[inline]
     fn remaining_mut(&self) -> usize {
         // A vector can never have more than isize::MAX bytes
-        core::isize::MAX as usize - self.len()
+        isize::MAX as usize - self.len()
     }
 
     #[inline]

src/buf/take.rs

@@ -163,24 +163,7 @@ impl<T: Buf> Buf for Take<T> {
         }
 
         const LEN: usize = 16;
-        let mut slices: [IoSlice<'a>; LEN] = [
-            IoSlice::new(&[]),
-            IoSlice::new(&[]),
-            IoSlice::new(&[]),
-            IoSlice::new(&[]),
-            IoSlice::new(&[]),
-            IoSlice::new(&[]),
-            IoSlice::new(&[]),
-            IoSlice::new(&[]),
-            IoSlice::new(&[]),
-            IoSlice::new(&[]),
-            IoSlice::new(&[]),
-            IoSlice::new(&[]),
-            IoSlice::new(&[]),
-            IoSlice::new(&[]),
-            IoSlice::new(&[]),
-            IoSlice::new(&[]),
-        ];
+        let mut slices: [IoSlice<'a>; LEN] = [IoSlice::new(&[]); LEN];
 
         let cnt = self
             .inner

src/bytes.rs

@@ -1,8 +1,7 @@
-use core::iter::FromIterator;
 use core::mem::{self, ManuallyDrop};
 use core::ops::{Deref, RangeBounds};
 use core::ptr::NonNull;
-use core::{cmp, fmt, hash, ptr, slice, usize};
+use core::{cmp, fmt, hash, ptr, slice};
 
 use alloc::{
     alloc::{dealloc, Layout},
@@ -16,7 +15,7 @@ use crate::buf::IntoIter;
 #[allow(unused)]
 use crate::loom::sync::atomic::AtomicMut;
 use crate::loom::sync::atomic::{AtomicPtr, AtomicUsize, Ordering};
-use crate::{offset_from, Buf, BytesMut};
+use crate::{Buf, BytesMut};
 
 /// A cheaply cloneable and sliceable chunk of contiguous memory.
 ///
@@ -112,9 +111,9 @@ pub(crate) struct Vtable {
     pub clone: unsafe fn(&AtomicPtr<()>, *const u8, usize) -> Bytes,
     /// fn(data, ptr, len)
     ///
-    /// takes `Bytes` to value
-    pub to_vec: unsafe fn(&AtomicPtr<()>, *const u8, usize) -> Vec<u8>,
-    pub to_mut: unsafe fn(&AtomicPtr<()>, *const u8, usize) -> BytesMut,
+    /// `into_*` consumes the `Bytes`, returning the respective value.
+    pub into_vec: unsafe fn(&AtomicPtr<()>, *const u8, usize) -> Vec<u8>,
+    pub into_mut: unsafe fn(&AtomicPtr<()>, *const u8, usize) -> BytesMut,
     /// fn(data)
     pub is_unique: unsafe fn(&AtomicPtr<()>) -> bool,
     /// fn(data, ptr, len)
@@ -268,10 +267,7 @@ impl Bytes {
         //                  and: https://github.com/tokio-rs/bytes/pull/742/#discussion_r1813316032
 
         let owned = Box::into_raw(Box::new(Owned {
-            lifetime: OwnedLifetime {
-                ref_cnt: AtomicUsize::new(1),
-                drop: owned_box_and_drop::<T>,
-            },
+            ref_cnt: AtomicUsize::new(1),
             owner,
         }));
 
@@ -279,7 +275,7 @@ impl Bytes {
             ptr: NonNull::dangling().as_ptr(),
             len: 0,
             data: AtomicPtr::new(owned.cast()),
-            vtable: &OWNED_VTABLE,
+            vtable: &Owned::<T>::VTABLE,
         };
 
         let buf = unsafe { &*owned }.owner.as_ref();
@@ -401,7 +397,7 @@ impl Bytes {
         );
 
         if end == begin {
-            return Bytes::new();
+            return Bytes::new_empty_with_ptr(self.ptr.wrapping_add(begin));
         }
 
         let mut ret = self.clone();
@@ -790,7 +786,7 @@ impl PartialEq for Bytes {
 
 impl PartialOrd for Bytes {
     fn partial_cmp(&self, other: &Bytes) -> Option<cmp::Ordering> {
-        self.as_slice().partial_cmp(other.as_slice())
+        Some(self.cmp(other))
     }
 }
 
@@ -1045,7 +1041,7 @@ impl From<Bytes> for BytesMut {
     /// ```
     fn from(bytes: Bytes) -> Self {
         let bytes = ManuallyDrop::new(bytes);
-        unsafe { (bytes.vtable.to_mut)(&bytes.data, bytes.ptr, bytes.len) }
+        unsafe { (bytes.vtable.into_mut)(&bytes.data, bytes.ptr, bytes.len) }
     }
 }
 
@@ -1058,7 +1054,7 @@ impl From<String> for Bytes {
 impl From<Bytes> for Vec<u8> {
     fn from(bytes: Bytes) -> Vec<u8> {
         let bytes = ManuallyDrop::new(bytes);
-        unsafe { (bytes.vtable.to_vec)(&bytes.data, bytes.ptr, bytes.len) }
+        unsafe { (bytes.vtable.into_vec)(&bytes.data, bytes.ptr, bytes.len) }
     }
 }
 
@@ -1077,8 +1073,8 @@ impl fmt::Debug for Vtable {
 
 const STATIC_VTABLE: Vtable = Vtable {
     clone: static_clone,
-    to_vec: static_to_vec,
-    to_mut: static_to_mut,
+    into_vec: static_to_vec,
+    into_mut: static_to_mut,
     is_unique: static_is_unique,
     drop: static_drop,
 };
@@ -1108,99 +1104,89 @@ unsafe fn static_drop(_: &mut AtomicPtr<()>, _: *const u8, _: usize) {
 
 // ===== impl OwnedVtable =====
 
-#[repr(C)]
-struct OwnedLifetime {
-    ref_cnt: AtomicUsize,
-    drop: unsafe fn(*mut ()),
-}
-
 #[repr(C)]
 struct Owned<T> {
-    lifetime: OwnedLifetime,
+    ref_cnt: AtomicUsize,
     owner: T,
 }
 
-unsafe fn owned_box_and_drop<T>(ptr: *mut ()) {
-    let b: Box<Owned<T>> = Box::from_raw(ptr as _);
-    drop(b);
+impl<T> Owned<T> {
+    const VTABLE: Vtable = Vtable {
+        clone: owned_clone::<T>,
+        into_vec: owned_to_vec::<T>,
+        into_mut: owned_to_mut::<T>,
+        is_unique: owned_is_unique,
+        drop: owned_drop::<T>,
+    };
 }
 
-unsafe fn owned_clone(data: &AtomicPtr<()>, ptr: *const u8, len: usize) -> Bytes {
+unsafe fn owned_clone<T>(data: &AtomicPtr<()>, ptr: *const u8, len: usize) -> Bytes {
     let owned = data.load(Ordering::Relaxed);
-    let ref_cnt = &(*owned.cast::<OwnedLifetime>()).ref_cnt;
-    let old_cnt = ref_cnt.fetch_add(1, Ordering::Relaxed);
+    let old_cnt = (*owned.cast::<AtomicUsize>()).fetch_add(1, Ordering::Relaxed);
     if old_cnt > usize::MAX >> 1 {
-        crate::abort()
+        crate::abort();
     }
 
     Bytes {
         ptr,
         len,
         data: AtomicPtr::new(owned as _),
-        vtable: &OWNED_VTABLE,
+        vtable: &Owned::<T>::VTABLE,
     }
 }
 
-unsafe fn owned_to_vec(data: &AtomicPtr<()>, ptr: *const u8, len: usize) -> Vec<u8> {
+unsafe fn owned_to_vec<T>(data: &AtomicPtr<()>, ptr: *const u8, len: usize) -> Vec<u8> {
     let slice = slice::from_raw_parts(ptr, len);
     let vec = slice.to_vec();
-    owned_drop_impl(data.load(Ordering::Relaxed));
+    owned_drop_impl::<T>(data.load(Ordering::Relaxed));
     vec
 }
 
-unsafe fn owned_to_mut(data: &AtomicPtr<()>, ptr: *const u8, len: usize) -> BytesMut {
-    BytesMut::from_vec(owned_to_vec(data, ptr, len))
+unsafe fn owned_to_mut<T>(data: &AtomicPtr<()>, ptr: *const u8, len: usize) -> BytesMut {
+    BytesMut::from_vec(owned_to_vec::<T>(data, ptr, len))
 }
 
 unsafe fn owned_is_unique(_data: &AtomicPtr<()>) -> bool {
     false
 }
 
-unsafe fn owned_drop_impl(owned: *mut ()) {
-    let lifetime = owned.cast::<OwnedLifetime>();
-    let ref_cnt = &(*lifetime).ref_cnt;
+unsafe fn owned_drop_impl<T>(owned: *mut ()) {
+    {
+        let ref_cnt = &*owned.cast::<AtomicUsize>();
 
-    let old_cnt = ref_cnt.fetch_sub(1, Ordering::Release);
-    debug_assert!(
-        old_cnt > 0 && old_cnt <= usize::MAX >> 1,
-        "expected non-zero refcount and no underflow"
-    );
-    if old_cnt != 1 {
-        return;
+        let old_cnt = ref_cnt.fetch_sub(1, Ordering::Release);
+        debug_assert!(
+            old_cnt > 0 && old_cnt <= usize::MAX >> 1,
+            "expected non-zero refcount and no underflow"
+        );
+        if old_cnt != 1 {
+            return;
+        }
+        ref_cnt.load(Ordering::Acquire);
     }
-    ref_cnt.load(Ordering::Acquire);
 
-    let drop_fn = &(*lifetime).drop;
-    drop_fn(owned)
+    drop(Box::<Owned<T>>::from_raw(owned.cast()));
 }
 
-unsafe fn owned_drop(data: &mut AtomicPtr<()>, _ptr: *const u8, _len: usize) {
+unsafe fn owned_drop<T>(data: &mut AtomicPtr<()>, _ptr: *const u8, _len: usize) {
     let owned = data.load(Ordering::Relaxed);
-    owned_drop_impl(owned);
+    owned_drop_impl::<T>(owned);
 }
 
-static OWNED_VTABLE: Vtable = Vtable {
-    clone: owned_clone,
-    to_vec: owned_to_vec,
-    to_mut: owned_to_mut,
-    is_unique: owned_is_unique,
-    drop: owned_drop,
-};
-
 // ===== impl PromotableVtable =====
 
 static PROMOTABLE_EVEN_VTABLE: Vtable = Vtable {
     clone: promotable_even_clone,
-    to_vec: promotable_even_to_vec,
-    to_mut: promotable_even_to_mut,
+    into_vec: promotable_even_to_vec,
+    into_mut: promotable_even_to_mut,
     is_unique: promotable_is_unique,
     drop: promotable_even_drop,
 };
 
 static PROMOTABLE_ODD_VTABLE: Vtable = Vtable {
     clone: promotable_odd_clone,
-    to_vec: promotable_odd_to_vec,
-    to_mut: promotable_odd_to_mut,
+    into_vec: promotable_odd_to_vec,
+    into_mut: promotable_odd_to_mut,
     is_unique: promotable_is_unique,
     drop: promotable_odd_drop,
 };
@@ -1235,7 +1221,7 @@ unsafe fn promotable_to_vec(
 
         let buf = f(shared);
 
-        let cap = offset_from(ptr, buf) + len;
+        let cap = ptr.offset_from(buf) as usize + len;
 
         // Copy back buffer
         ptr::copy(ptr, buf, len);
@@ -1263,7 +1249,7 @@ unsafe fn promotable_to_mut(
         debug_assert_eq!(kind, KIND_VEC);
 
         let buf = f(shared);
-        let off = offset_from(ptr, buf);
+        let off = ptr.offset_from(buf) as usize;
         let cap = off + len;
         let v = Vec::from_raw_parts(buf, cap, cap);
 
@@ -1348,7 +1334,7 @@ unsafe fn promotable_is_unique(data: &AtomicPtr<()>) -> bool {
 }
 
 unsafe fn free_boxed_slice(buf: *mut u8, offset: *const u8, len: usize) {
-    let cap = offset_from(offset, buf) + len;
+    let cap = offset.offset_from(buf) as usize + len;
     dealloc(buf, Layout::from_size_align(cap, 1).unwrap())
 }
 
@@ -1375,8 +1361,8 @@ const _: [(); 0 - mem::align_of::<Shared>() % 2] = []; // Assert that the alignm
 
 static SHARED_VTABLE: Vtable = Vtable {
     clone: shared_clone,
-    to_vec: shared_to_vec,
-    to_mut: shared_to_mut,
+    into_vec: shared_to_vec,
+    into_mut: shared_to_mut,
     is_unique: shared_is_unique,
     drop: shared_drop,
 };
@@ -1444,7 +1430,7 @@ unsafe fn shared_to_mut_impl(shared: *mut Shared, ptr: *const u8, len: usize) ->
         let cap = shared.cap;
 
         // Rebuild Vec
-        let off = offset_from(ptr, buf);
+        let off = ptr.offset_from(buf) as usize;
         let v = Vec::from_raw_parts(buf, len + off, cap);
 
         let mut b = BytesMut::from_vec(v);
@@ -1510,7 +1496,7 @@ unsafe fn shallow_clone_vec(
     // vector.
     let shared = Box::new(Shared {
         buf,
-        cap: offset_from(offset, buf) + len,
+        cap: offset.offset_from(buf) as usize + len,
         // Initialize refcount to 2. One for this reference, and one
         // for the new clone that will be returned from
         // `shallow_clone`.
@@ -1537,7 +1523,7 @@ unsafe fn shallow_clone_vec(
     // pointed to by `actual` will be visible.
     match atom.compare_exchange(ptr as _, shared as _, Ordering::AcqRel, Ordering::Acquire) {
         Ok(actual) => {
-            debug_assert!(actual as usize == ptr as usize);
+            debug_assert!(core::ptr::eq(actual, ptr));
             // The upgrade was successful, the new handle can be
             // returned.
             Bytes {

src/bytes_mut.rs

@@ -1,8 +1,7 @@
-use core::iter::FromIterator;
 use core::mem::{self, ManuallyDrop, MaybeUninit};
 use core::ops::{Deref, DerefMut};
 use core::ptr::{self, NonNull};
-use core::{cmp, fmt, hash, isize, slice, usize};
+use core::{cmp, fmt, hash, slice};
 
 use alloc::{
     borrow::{Borrow, BorrowMut},
@@ -17,7 +16,7 @@ use crate::bytes::Vtable;
 #[allow(unused)]
 use crate::loom::sync::atomic::AtomicMut;
 use crate::loom::sync::atomic::{AtomicPtr, AtomicUsize, Ordering};
-use crate::{offset_from, Buf, BufMut, Bytes, TryGetError};
+use crate::{Buf, BufMut, Bytes, TryGetError};
 
 /// A unique reference to a contiguous slice of memory.
 ///
@@ -226,7 +225,7 @@ impl BytesMut {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```ignore-wasm
     /// use bytes::{BytesMut, BufMut};
     /// use std::thread;
     ///
@@ -694,7 +693,7 @@ impl BytesMut {
                 let v_capacity = v.capacity();
                 let ptr = v.as_mut_ptr();
 
-                let offset = offset_from(self.ptr.as_ptr(), ptr);
+                let offset = self.ptr.as_ptr().offset_from(ptr) as usize;
 
                 // Compare the condition in the `kind == KIND_VEC` case above
                 // for more details.
@@ -780,7 +779,7 @@ impl BytesMut {
         self.ptr = vptr(v.as_mut_ptr());
         self.cap = v.capacity();
         debug_assert_eq!(self.len, v.len());
-        return true;
+        true
     }
 
     /// Attempts to cheaply reclaim already allocated capacity for at least `additional` more
@@ -986,7 +985,7 @@ impl BytesMut {
         // new start and updating the `len` field to reflect the new length
         // of the view.
         self.ptr = vptr(self.ptr.as_ptr().add(count));
-        self.len = self.len.checked_sub(count).unwrap_or(0);
+        self.len = self.len.saturating_sub(count);
         self.cap -= count;
     }
 
@@ -1171,7 +1170,8 @@ impl Buf for BytesMut {
 unsafe impl BufMut for BytesMut {
     #[inline]
     fn remaining_mut(&self) -> usize {
-        usize::MAX - self.len()
+        // Max allocation size is isize::MAX.
+        isize::MAX as usize - self.len()
     }
 
     #[inline]
@@ -1202,11 +1202,27 @@ unsafe impl BufMut for BytesMut {
     where
         Self: Sized,
     {
-        while src.has_remaining() {
-            let s = src.chunk();
-            let l = s.len();
-            self.extend_from_slice(s);
-            src.advance(l);
+        if !src.has_remaining() {
+            // prevent calling `copy_to_bytes`->`put`->`copy_to_bytes` infintely when src is empty
+            return;
+        } else if self.capacity() == 0 {
+            // When capacity is zero, try reusing allocation of `src`.
+            let src_copy = src.copy_to_bytes(src.remaining());
+            drop(src);
+            match src_copy.try_into_mut() {
+                Ok(bytes_mut) => *self = bytes_mut,
+                Err(bytes) => self.extend_from_slice(&bytes),
+            }
+        } else {
+            // In case the src isn't contiguous, reserve upfront.
+            self.reserve(src.remaining());
+
+            while src.has_remaining() {
+                let s = src.chunk();
+                let l = s.len();
+                self.extend_from_slice(s);
+                src.advance(l);
+            }
         }
     }
 
@@ -1284,7 +1300,7 @@ impl PartialEq for BytesMut {
 
 impl PartialOrd for BytesMut {
     fn partial_cmp(&self, other: &BytesMut) -> Option<cmp::Ordering> {
-        self.as_slice().partial_cmp(other.as_slice())
+        Some(self.cmp(other))
     }
 }
 
@@ -1719,10 +1735,10 @@ impl From<BytesMut> for Vec<u8> {
                 rebuild_vec(bytes.ptr.as_ptr(), bytes.len, bytes.cap, off)
             }
         } else {
-            let shared = bytes.data as *mut Shared;
+            let shared = bytes.data;
 
             if unsafe { (*shared).is_unique() } {
-                let vec = mem::replace(unsafe { &mut (*shared).vec }, Vec::new());
+                let vec = core::mem::take(unsafe { &mut (*shared).vec });
 
                 unsafe { release_shared(shared) };
 
@@ -1776,8 +1792,8 @@ unsafe fn rebuild_vec(ptr: *mut u8, mut len: usize, mut cap: usize, off: usize)
 
 static SHARED_VTABLE: Vtable = Vtable {
     clone: shared_v_clone,
-    to_vec: shared_v_to_vec,
-    to_mut: shared_v_to_mut,
+    into_vec: shared_v_to_vec,
+    into_mut: shared_v_to_mut,
     is_unique: shared_v_is_unique,
     drop: shared_v_drop,
 };
@@ -1797,7 +1813,7 @@ unsafe fn shared_v_to_vec(data: &AtomicPtr<()>, ptr: *const u8, len: usize) -> V
         let shared = &mut *shared;
 
         // Drop shared
-        let mut vec = mem::replace(&mut shared.vec, Vec::new());
+        let mut vec = core::mem::take(&mut shared.vec);
         release_shared(shared);
 
         // Copy back buffer
@@ -1823,7 +1839,7 @@ unsafe fn shared_v_to_mut(data: &AtomicPtr<()>, ptr: *const u8, len: usize) -> B
         let v = &mut shared.vec;
         let v_capacity = v.capacity();
         let v_ptr = v.as_mut_ptr();
-        let offset = offset_from(ptr as *mut u8, v_ptr);
+        let offset = ptr.offset_from(v_ptr) as usize;
         let cap = v_capacity - offset;
 
         let ptr = vptr(ptr as *mut u8);

src/lib.rs

@@ -114,7 +114,6 @@ fn abort() -> ! {
 #[inline(always)]
 #[cfg(feature = "std")]
 fn saturating_sub_usize_u64(a: usize, b: u64) -> usize {
-    use core::convert::TryFrom;
     match usize::try_from(b) {
         Ok(b) => a.saturating_sub(b),
         Err(_) => 0,
@@ -124,7 +123,6 @@ fn saturating_sub_usize_u64(a: usize, b: u64) -> usize {
 #[inline(always)]
 #[cfg(feature = "std")]
 fn min_u64_usize(a: u64, b: usize) -> usize {
-    use core::convert::TryFrom;
     match usize::try_from(a) {
         Ok(a) => usize::min(a, b),
         Err(_) => b,
@@ -182,18 +180,3 @@ fn panic_does_not_fit(size: usize, nbytes: usize) -> ! {
         size, nbytes
     );
 }
-
-/// Precondition: dst >= original
-///
-/// The following line is equivalent to:
-///
-/// ```rust,ignore
-/// self.ptr.as_ptr().offset_from(ptr) as usize;
-/// ```
-///
-/// But due to min rust is 1.39 and it is only stabilized
-/// in 1.47, we cannot use it.
-#[inline]
-fn offset_from(dst: *const u8, original: *const u8) -> usize {
-    dst as usize - original as usize
-}

tests/test_buf_mut.rs

@@ -4,7 +4,6 @@ use bytes::buf::UninitSlice;
 use bytes::{BufMut, BytesMut};
 use core::fmt::Write;
 use core::mem::MaybeUninit;
-use core::usize;
 
 #[test]
 fn test_vec_as_mut_buf() {
@@ -274,3 +273,12 @@ fn copy_from_slice_panics_if_different_length_2() {
     let slice = unsafe { UninitSlice::from_raw_parts_mut(data.as_mut_ptr(), 3) };
     slice.copy_from_slice(b"abcd");
 }
+
+/// Test if with zero capacity BytesMut does not infinitely recurse in put from Buf
+#[test]
+fn test_bytes_mut_reuse() {
+    let mut buf = BytesMut::new();
+    buf.put(&[] as &[u8]);
+    let mut buf = BytesMut::new();
+    buf.put(&[1u8, 2, 3] as &[u8]);
+}

tests/test_bytes.rs

@@ -5,7 +5,6 @@ use std::sync::atomic::{AtomicUsize, Ordering};
 use std::sync::Arc;
 
 use std::panic::{self, AssertUnwindSafe};
-use std::usize;
 
 const LONG: &[u8] = b"mary had a little lamb, little lamb, little lamb";
 const SHORT: &[u8] = b"hello world";
@@ -82,7 +81,6 @@ fn fmt() {
 #[test]
 fn fmt_write() {
     use std::fmt::Write;
-    use std::iter::FromIterator;
     let s = String::from_iter((0..10).map(|_| "abcdefg"));
 
     let mut a = BytesMut::with_capacity(64);
@@ -157,6 +155,13 @@ fn slice_oob_2() {
     a.slice(44..49);
 }
 
+#[test]
+#[should_panic]
+fn slice_start_greater_than_end() {
+    let a = Bytes::from(&b"hello world"[..]);
+    a.slice(5..3);
+}
+
 #[test]
 fn split_off() {
     let mut hello = Bytes::from(&b"helloworld"[..]);
@@ -179,6 +184,13 @@ fn split_off_oob() {
     let _ = hello.split_off(44);
 }
 
+#[test]
+#[should_panic = "split_off out of bounds"]
+fn bytes_mut_split_off_oob() {
+    let mut hello = BytesMut::from(&b"helloworld"[..]);
+    let _ = hello.split_off(44);
+}
+
 #[test]
 fn split_off_uninitialized() {
     let mut bytes = BytesMut::with_capacity(1024);
@@ -724,6 +736,15 @@ fn advance_past_len() {
     a.advance(20);
 }
 
+#[test]
+#[should_panic]
+fn mut_advance_past_len() {
+    let mut a = BytesMut::from("hello world");
+    unsafe {
+        a.advance_mut(20);
+    }
+}
+
 #[test]
 // Only run these tests on little endian systems. CI uses qemu for testing
 // big endian... and qemu doesn't really support threading all that well.
@@ -1405,6 +1426,26 @@ fn try_reclaim_arc() {
     assert_eq!(true, buf.try_reclaim(6));
 }
 
+#[test]
+fn slice_empty_addr() {
+    let buf = Bytes::from(vec![0; 1024]);
+
+    let ptr_start = buf.as_ptr();
+    let ptr_end = ptr_start.wrapping_add(1024);
+
+    let empty_end = buf.slice(1024..);
+    assert_eq!(empty_end.len(), 0);
+    assert_eq!(empty_end.as_ptr(), ptr_end);
+
+    let empty_start = buf.slice(..0);
+    assert_eq!(empty_start.len(), 0);
+    assert_eq!(empty_start.as_ptr(), ptr_start);
+
+    // Is miri happy about the provenance?
+    let _ = &empty_end[..];
+    let _ = &empty_start[..];
+}
+
 #[test]
 fn split_off_empty_addr() {
     let mut buf = Bytes::from(vec![0; 1024]);
@@ -1647,3 +1688,22 @@ fn owned_safe_drop_on_as_ref_panic() {
     assert!(result.is_err());
     assert_eq!(drop_counter.get(), 1);
 }
+
+/// Test `BytesMut::put` reuses allocation of `Bytes`.
+#[test]
+fn bytes_mut_put_bytes_specialization() {
+    let mut vec = Vec::with_capacity(1234);
+    vec.push(10);
+    let capacity = vec.capacity();
+    assert!(capacity >= 1234);
+
+    // Make `Bytes` backed by `Vec`.
+    let bytes = Bytes::from(vec);
+    let mut bytes_mut = BytesMut::new();
+    bytes_mut.put(bytes);
+
+    // Check contents is correct.
+    assert_eq!(&[10], bytes_mut.as_ref());
+    // If allocation is reused, capacity should be equal to original vec capacity.
+    assert_eq!(bytes_mut.capacity(), capacity);
+}

tests/test_chain.rs

@@ -135,7 +135,7 @@ fn vectored_read() {
 
 #[test]
 fn chain_growing_buffer() {
-    let mut buff = [' ' as u8; 10];
+    let mut buff = [b' '; 10];
     let mut vec = b"wassup".to_vec();
 
     let mut chained = (&mut buff[..]).chain_mut(&mut vec).chain_mut(Vec::new()); // Required for potential overflow because remaining_mut for Vec is isize::MAX - vec.len(), but for chain_mut is usize::MAX

tests/test_limit.rs

@@ -0,0 +1,86 @@
+#![warn(rust_2018_idioms)]
+
+use bytes::{buf::Limit, BufMut};
+
+#[test]
+fn long_limit() {
+    let buf = &mut [0u8; 10];
+    let limit = buf.limit(100);
+    assert_eq!(10, limit.remaining_mut());
+    assert_eq!(&[0u8; 10], &limit.get_ref()[..]);
+}
+
+#[test]
+fn limit_get_mut() {
+    let buf = &mut [0u8; 128];
+    let mut limit = buf.limit(10);
+    assert_eq!(10, limit.remaining_mut());
+    assert_eq!(&mut [0u8; 128], &limit.get_mut()[..]);
+}
+
+#[test]
+fn limit_set_limit() {
+    let buf = &mut [0u8; 128];
+    let mut limit = buf.limit(10);
+    assert_eq!(10, Limit::limit(&limit));
+    limit.set_limit(5);
+    assert_eq!(5, Limit::limit(&limit));
+}
+
+#[test]
+fn limit_chunk_mut() {
+    let buf = &mut [0u8; 20];
+    let mut limit = buf.limit(10);
+    assert_eq!(10, limit.chunk_mut().len());
+
+    let buf = &mut [0u8; 10];
+    let mut limit = buf.limit(20);
+    assert_eq!(10, limit.chunk_mut().len());
+}
+
+#[test]
+#[should_panic = "advance out of bounds"]
+fn limit_advance_mut_panic_1() {
+    let buf = &mut [0u8; 10];
+    let mut limit = buf.limit(100);
+    unsafe {
+        limit.advance_mut(50);
+    }
+}
+
+#[test]
+#[should_panic = "cnt <= self.limit"]
+fn limit_advance_mut_panic_2() {
+    let buf = &mut [0u8; 100];
+    let mut limit = buf.limit(10);
+    unsafe {
+        limit.advance_mut(50);
+    }
+}
+
+#[test]
+fn limit_advance_mut() {
+    let buf = &mut [0u8; 100];
+    let mut limit = buf.limit(10);
+    unsafe {
+        limit.advance_mut(5);
+    }
+    assert_eq!(5, limit.remaining_mut());
+    assert_eq!(5, limit.chunk_mut().len());
+}
+
+#[test]
+fn limit_into_inner() {
+    let buf_arr = *b"hello world";
+    let buf: &mut [u8] = &mut buf_arr.clone();
+    let mut limit = buf.limit(4);
+    let mut dst = vec![];
+
+    unsafe {
+        limit.advance_mut(2);
+    }
+
+    let buf = limit.into_inner();
+    dst.put(&buf[..]);
+    assert_eq!(*dst, b"llo world"[..]);
+}

tests/test_reader.rs

@@ -27,3 +27,12 @@ fn buf_read() {
     reader.read_line(&mut line).unwrap();
     assert_eq!("world", &line);
 }
+
+#[test]
+fn get_mut() {
+    let buf = &b"hello world"[..];
+    let mut reader = buf.reader();
+    let buf_mut = reader.get_mut();
+    assert_eq!(11, buf_mut.remaining());
+    assert_eq!(b"hello world", buf_mut);
+}