mirror of
https://github.com/openharmony/third_party_rust_bytes.git
synced 2026-07-18 16:24:29 -04:00
Sean McArthur
c3f9cf1d72
Bytes is a useful tool for managing multiple slices into the same region of memory, and the other things it used to have been removed to reduce complexity. The exact strategy for managing the multiple references is no longer hard-coded, but instead backing by a customizable vtable. - Removed ability to mutate the underlying memory from the `Bytes` type. - Removed the "inline" (SBO) mechanism in `Bytes`. The reduces a large amount of complexity, and improves performance when accessing the slice of bytes, since a branch is no longer needed to check if the data is inline. - Removed `Bytes` knowledge of `BytesMut` (`BytesMut` may grow that knowledge back at a future point.)
1430 lines
40 KiB
Rust
1430 lines
40 KiB
Rust
use core::{cmp, fmt, hash, isize, mem, slice, usize};
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use core::ops::{Deref, DerefMut};
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use core::ptr::{self, NonNull};
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use core::iter::{FromIterator, Iterator};
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use alloc::{vec::Vec, string::String, boxed::Box, borrow::{Borrow, BorrowMut}};
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use crate::{Bytes, Buf, BufMut};
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use crate::bytes::Vtable;
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use crate::buf::IntoIter;
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use crate::debug;
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use crate::loom::sync::atomic::{self, AtomicPtr, AtomicUsize, Ordering};
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/// A unique reference to a contiguous slice of memory.
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///
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/// `BytesMut` represents a unique view into a potentially shared memory region.
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/// Given the uniqueness guarantee, owners of `BytesMut` handles are able to
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/// mutate the memory. It is similar to a `Vec<u8>` but with less copies and
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/// allocations.
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///
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/// # Growth
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///
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/// One key difference from `Vec<u8>` is that most operations **do not
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/// implicitly grow the buffer**. This means that calling `my_bytes.put("hello
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/// world");` could panic if `my_bytes` does not have enough capacity. Before
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/// writing to the buffer, ensure that there is enough remaining capacity by
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/// calling `my_bytes.remaining_mut()`. In general, avoiding calls to `reserve`
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/// is preferable.
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///
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/// The only exception is `extend` which implicitly reserves required capacity.
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///
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/// # Examples
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///
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/// ```
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/// use bytes::{BytesMut, BufMut};
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///
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/// let mut buf = BytesMut::with_capacity(64);
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///
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/// buf.put_u8(b'h');
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/// buf.put_u8(b'e');
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/// buf.put("llo");
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///
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/// assert_eq!(&buf[..], b"hello");
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///
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/// // Freeze the buffer so that it can be shared
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/// let a = buf.freeze();
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///
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/// // This does not allocate, instead `b` points to the same memory.
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/// let b = a.clone();
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///
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/// assert_eq!(&a[..], b"hello");
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/// assert_eq!(&b[..], b"hello");
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/// ```
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pub struct BytesMut {
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ptr: NonNull<u8>,
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len: usize,
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cap: usize,
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data: *mut Shared,
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}
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// Thread-safe reference-counted container for the shared storage. This mostly
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// the same as `core::sync::Arc` but without the weak counter. The ref counting
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// fns are based on the ones found in `std`.
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//
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// The main reason to use `Shared` instead of `core::sync::Arc` is that it ends
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// up making the overall code simpler and easier to reason about. This is due to
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// some of the logic around setting `Inner::arc` and other ways the `arc` field
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// is used. Using `Arc` ended up requiring a number of funky transmutes and
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// other shenanigans to make it work.
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struct Shared {
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vec: Vec<u8>,
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original_capacity_repr: usize,
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ref_count: AtomicUsize,
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}
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// Buffer storage strategy flags.
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const KIND_ARC: usize = 0b0;
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const KIND_VEC: usize = 0b1;
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const KIND_MASK: usize = 0b1;
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// The max original capacity value. Any `Bytes` allocated with a greater initial
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// capacity will default to this.
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const MAX_ORIGINAL_CAPACITY_WIDTH: usize = 17;
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// The original capacity algorithm will not take effect unless the originally
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// allocated capacity was at least 1kb in size.
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const MIN_ORIGINAL_CAPACITY_WIDTH: usize = 10;
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// The original capacity is stored in powers of 2 starting at 1kb to a max of
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// 64kb. Representing it as such requires only 3 bits of storage.
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const ORIGINAL_CAPACITY_MASK: usize = 0b11100;
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const ORIGINAL_CAPACITY_OFFSET: usize = 2;
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// When the storage is in the `Vec` representation, the pointer can be advanced
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// at most this value. This is due to the amount of storage available to track
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// the offset is usize - number of KIND bits and number of ORIGINAL_CAPACITY
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// bits.
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const VEC_POS_OFFSET: usize = 5;
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const MAX_VEC_POS: usize = usize::MAX >> VEC_POS_OFFSET;
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const NOT_VEC_POS_MASK: usize = 0b11111;
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#[cfg(target_pointer_width = "64")]
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const PTR_WIDTH: usize = 64;
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#[cfg(target_pointer_width = "32")]
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const PTR_WIDTH: usize = 32;
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/*
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*
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* ===== BytesMut =====
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*
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*/
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impl BytesMut {
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/// Creates a new `BytesMut` with the specified capacity.
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///
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/// The returned `BytesMut` will be able to hold at least `capacity` bytes
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/// without reallocating. If `capacity` is under `4 * size_of::<usize>() - 1`,
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/// then `BytesMut` will not allocate.
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///
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/// It is important to note that this function does not specify the length
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/// of the returned `BytesMut`, but only the capacity.
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///
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/// # Examples
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///
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/// ```
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/// use bytes::{BytesMut, BufMut};
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///
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/// let mut bytes = BytesMut::with_capacity(64);
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///
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/// // `bytes` contains no data, even though there is capacity
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/// assert_eq!(bytes.len(), 0);
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///
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/// bytes.put(&b"hello world"[..]);
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///
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/// assert_eq!(&bytes[..], b"hello world");
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/// ```
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#[inline]
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pub fn with_capacity(capacity: usize) -> BytesMut {
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BytesMut::from_vec(Vec::with_capacity(capacity))
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}
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/// Creates a new `BytesMut` with default capacity.
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///
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/// Resulting object has length 0 and unspecified capacity.
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/// This function does not allocate.
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///
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/// # Examples
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///
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/// ```
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/// use bytes::{BytesMut, BufMut};
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///
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/// let mut bytes = BytesMut::new();
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///
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/// assert_eq!(0, bytes.len());
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///
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/// bytes.reserve(2);
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/// bytes.put_slice(b"xy");
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///
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/// assert_eq!(&b"xy"[..], &bytes[..]);
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/// ```
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#[inline]
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pub fn new() -> BytesMut {
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BytesMut::with_capacity(0)
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}
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/// Returns the number of bytes contained in this `BytesMut`.
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///
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/// # Examples
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///
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/// ```
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/// use bytes::BytesMut;
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///
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/// let b = BytesMut::from(&b"hello"[..]);
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/// assert_eq!(b.len(), 5);
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/// ```
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#[inline]
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pub fn len(&self) -> usize {
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self.len
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}
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/// Returns true if the `BytesMut` has a length of 0.
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///
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/// # Examples
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///
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/// ```
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/// use bytes::BytesMut;
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///
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/// let b = BytesMut::with_capacity(64);
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/// assert!(b.is_empty());
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/// ```
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#[inline]
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pub fn is_empty(&self) -> bool {
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self.len == 0
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}
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/// Returns the number of bytes the `BytesMut` can hold without reallocating.
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///
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/// # Examples
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///
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/// ```
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/// use bytes::BytesMut;
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///
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/// let b = BytesMut::with_capacity(64);
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/// assert_eq!(b.capacity(), 64);
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/// ```
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#[inline]
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pub fn capacity(&self) -> usize {
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self.cap
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}
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/// Converts `self` into an immutable `Bytes`.
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///
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/// The conversion is zero cost and is used to indicate that the slice
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/// referenced by the handle will no longer be mutated. Once the conversion
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/// is done, the handle can be cloned and shared across threads.
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///
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/// # Examples
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///
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/// ```
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/// use bytes::{BytesMut, BufMut};
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/// use std::thread;
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///
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/// let mut b = BytesMut::with_capacity(64);
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/// b.put("hello world");
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/// let b1 = b.freeze();
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/// let b2 = b1.clone();
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///
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/// let th = thread::spawn(move || {
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/// assert_eq!(&b1[..], b"hello world");
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/// });
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///
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/// assert_eq!(&b2[..], b"hello world");
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/// th.join().unwrap();
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/// ```
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#[inline]
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pub fn freeze(mut self) -> Bytes {
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if self.kind() == KIND_VEC {
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// Just re-use `Bytes` internal Vec vtable
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unsafe {
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let (off, _) = self.get_vec_pos();
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let vec = rebuild_vec(self.ptr.as_ptr(), self.len, self.cap, off);
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mem::forget(self);
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vec.into()
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}
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} else {
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debug_assert_eq!(self.kind(), KIND_ARC);
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let ptr = self.ptr.as_ptr();
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let len = self.len;
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let data = AtomicPtr::new(self.data as _);
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mem::forget(self);
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unsafe {
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Bytes::with_vtable(ptr, len, data, &SHARED_VTABLE)
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}
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}
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}
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/// Splits the bytes into two at the given index.
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///
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/// Afterwards `self` contains elements `[0, at)`, and the returned
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/// `BytesMut` contains elements `[at, capacity)`.
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///
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/// This is an `O(1)` operation that just increases the reference count
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/// and sets a few indices.
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///
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/// # Examples
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///
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/// ```
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/// use bytes::BytesMut;
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///
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/// let mut a = BytesMut::from(&b"hello world"[..]);
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/// let mut b = a.split_off(5);
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///
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/// a[0] = b'j';
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/// b[0] = b'!';
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///
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/// assert_eq!(&a[..], b"jello");
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/// assert_eq!(&b[..], b"!world");
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/// ```
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///
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/// # Panics
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///
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/// Panics if `at > capacity`.
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pub fn split_off(&mut self, at: usize) -> BytesMut {
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assert!(at <= self.capacity());
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unsafe {
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let mut other = self.shallow_clone();
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other.set_start(at);
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self.set_end(at);
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other
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}
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}
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/// Removes the bytes from the current view, returning them in a new
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/// `BytesMut` handle.
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///
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/// Afterwards, `self` will be empty, but will retain any additional
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/// capacity that it had before the operation. This is identical to
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/// `self.split_to(self.len())`.
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///
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/// This is an `O(1)` operation that just increases the reference count and
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/// sets a few indices.
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///
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/// # Examples
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///
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/// ```
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/// use bytes::{BytesMut, BufMut};
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///
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/// let mut buf = BytesMut::with_capacity(1024);
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/// buf.put(&b"hello world"[..]);
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///
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/// let other = buf.split();
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///
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/// assert!(buf.is_empty());
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/// assert_eq!(1013, buf.capacity());
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///
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/// assert_eq!(other, b"hello world"[..]);
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/// ```
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pub fn split(&mut self) -> BytesMut {
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let len = self.len();
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self.split_to(len)
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}
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/// Splits the buffer into two at the given index.
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///
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/// Afterwards `self` contains elements `[at, len)`, and the returned `BytesMut`
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/// contains elements `[0, at)`.
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///
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/// This is an `O(1)` operation that just increases the reference count and
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/// sets a few indices.
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///
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/// # Examples
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///
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/// ```
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/// use bytes::BytesMut;
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///
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/// let mut a = BytesMut::from(&b"hello world"[..]);
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/// let mut b = a.split_to(5);
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///
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/// a[0] = b'!';
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/// b[0] = b'j';
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///
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/// assert_eq!(&a[..], b"!world");
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/// assert_eq!(&b[..], b"jello");
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/// ```
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///
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/// # Panics
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///
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/// Panics if `at > len`.
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pub fn split_to(&mut self, at: usize) -> BytesMut {
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assert!(at <= self.len());
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unsafe {
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let mut other = self.shallow_clone();
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other.set_end(at);
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self.set_start(at);
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other
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}
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}
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/// Shortens the buffer, keeping the first `len` bytes and dropping the
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/// rest.
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///
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/// If `len` is greater than the buffer's current length, this has no
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/// effect.
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///
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/// The [`split_off`] method can emulate `truncate`, but this causes the
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/// excess bytes to be returned instead of dropped.
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///
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/// # Examples
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///
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/// ```
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/// use bytes::BytesMut;
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///
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/// let mut buf = BytesMut::from(&b"hello world"[..]);
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/// buf.truncate(5);
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/// assert_eq!(buf, b"hello"[..]);
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/// ```
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///
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/// [`split_off`]: #method.split_off
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pub fn truncate(&mut self, len: usize) {
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if len <= self.len() {
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unsafe { self.set_len(len); }
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}
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}
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/// Clears the buffer, removing all data.
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///
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/// # Examples
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///
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/// ```
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/// use bytes::BytesMut;
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///
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/// let mut buf = BytesMut::from(&b"hello world"[..]);
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/// buf.clear();
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/// assert!(buf.is_empty());
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/// ```
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pub fn clear(&mut self) {
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self.truncate(0);
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}
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/// Resizes the buffer so that `len` is equal to `new_len`.
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///
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/// If `new_len` is greater than `len`, the buffer is extended by the
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/// difference with each additional byte set to `value`. If `new_len` is
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/// less than `len`, the buffer is simply truncated.
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///
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/// # Examples
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///
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/// ```
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/// use bytes::BytesMut;
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///
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/// let mut buf = BytesMut::new();
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///
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/// buf.resize(3, 0x1);
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/// assert_eq!(&buf[..], &[0x1, 0x1, 0x1]);
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///
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/// buf.resize(2, 0x2);
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/// assert_eq!(&buf[..], &[0x1, 0x1]);
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///
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/// buf.resize(4, 0x3);
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/// assert_eq!(&buf[..], &[0x1, 0x1, 0x3, 0x3]);
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/// ```
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pub fn resize(&mut self, new_len: usize, value: u8) {
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let len = self.len();
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if new_len > len {
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let additional = new_len - len;
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self.reserve(additional);
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unsafe {
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let dst = self.bytes_mut().as_mut_ptr();
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ptr::write_bytes(dst, value, additional);
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self.set_len(new_len);
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}
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} else {
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self.truncate(new_len);
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}
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}
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/// Sets the length of the buffer.
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///
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/// This will explicitly set the size of the buffer without actually
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/// modifying the data, so it is up to the caller to ensure that the data
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/// has been initialized.
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///
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/// # Examples
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///
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/// ```
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/// use bytes::BytesMut;
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///
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/// let mut b = BytesMut::from(&b"hello world"[..]);
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///
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/// unsafe {
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/// b.set_len(5);
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/// }
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///
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/// assert_eq!(&b[..], b"hello");
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///
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/// unsafe {
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/// b.set_len(11);
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/// }
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///
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/// assert_eq!(&b[..], b"hello world");
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/// ```
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pub unsafe fn set_len(&mut self, len: usize) {
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debug_assert!(len <= self.cap);
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self.len = len;
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}
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|
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/// Reserves capacity for at least `additional` more bytes to be inserted
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/// into the given `BytesMut`.
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///
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/// More than `additional` bytes may be reserved in order to avoid frequent
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/// reallocations. A call to `reserve` may result in an allocation.
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///
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/// Before allocating new buffer space, the function will attempt to reclaim
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/// space in the existing buffer. If the current handle references a small
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/// view in the original buffer and all other handles have been dropped,
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/// and the requested capacity is less than or equal to the existing
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/// buffer's capacity, then the current view will be copied to the front of
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/// the buffer and the handle will take ownership of the full buffer.
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///
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/// # Examples
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|
///
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/// In the following example, a new buffer is allocated.
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///
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/// ```
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/// use bytes::BytesMut;
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///
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/// let mut buf = BytesMut::from(&b"hello"[..]);
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/// buf.reserve(64);
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/// assert!(buf.capacity() >= 69);
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/// ```
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///
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/// In the following example, the existing buffer is reclaimed.
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///
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/// ```
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/// use bytes::{BytesMut, BufMut};
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///
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/// let mut buf = BytesMut::with_capacity(128);
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/// buf.put(&[0; 64][..]);
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///
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/// let ptr = buf.as_ptr();
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/// let other = buf.split();
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///
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/// assert!(buf.is_empty());
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/// assert_eq!(buf.capacity(), 64);
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///
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/// drop(other);
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/// buf.reserve(128);
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///
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/// assert_eq!(buf.capacity(), 128);
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/// assert_eq!(buf.as_ptr(), ptr);
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/// ```
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///
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/// # Panics
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|
///
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/// Panics if the new capacity overflows `usize`.
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|
pub fn reserve(&mut self, additional: usize) {
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let len = self.len();
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let rem = self.capacity() - len;
|
|
|
|
if additional <= rem {
|
|
// The handle can already store at least `additional` more bytes, so
|
|
// there is no further work needed to be done.
|
|
return;
|
|
}
|
|
|
|
let kind = self.kind();
|
|
|
|
if kind == KIND_VEC {
|
|
// If there's enough free space before the start of the buffer, then
|
|
// just copy the data backwards and reuse the already-allocated
|
|
// space.
|
|
//
|
|
// Otherwise, since backed by a vector, use `Vec::reserve`
|
|
unsafe {
|
|
let (off, prev) = self.get_vec_pos();
|
|
|
|
// Only reuse space if we stand to gain at least capacity/2
|
|
// bytes of space back
|
|
if off >= additional && off >= (self.cap / 2) {
|
|
// There's space - reuse it
|
|
//
|
|
// Just move the pointer back to the start after copying
|
|
// data back.
|
|
let base_ptr = self.ptr.as_ptr().offset(-(off as isize));
|
|
ptr::copy(self.ptr.as_ptr(), base_ptr, self.len);
|
|
self.ptr = vptr(base_ptr);
|
|
self.set_vec_pos(0, prev);
|
|
|
|
// Length stays constant, but since we moved backwards we
|
|
// can gain capacity back.
|
|
self.cap += off;
|
|
} else {
|
|
// No space - allocate more
|
|
let mut v = rebuild_vec(self.ptr.as_ptr(), self.len, self.cap, off);
|
|
v.reserve(additional);
|
|
|
|
// Update the info
|
|
self.ptr = vptr(v.as_mut_ptr().offset(off as isize));
|
|
self.len = v.len() - off;
|
|
self.cap = v.capacity() - off;
|
|
|
|
// Drop the vec reference
|
|
mem::forget(v);
|
|
}
|
|
return;
|
|
}
|
|
}
|
|
|
|
debug_assert_eq!(kind, KIND_ARC);
|
|
let shared: *mut Shared = self.data as _;
|
|
|
|
|
|
// Reserving involves abandoning the currently shared buffer and
|
|
// allocating a new vector with the requested capacity.
|
|
//
|
|
// Compute the new capacity
|
|
let mut new_cap = len + additional;
|
|
let original_capacity;
|
|
let original_capacity_repr;
|
|
|
|
unsafe {
|
|
original_capacity_repr = (*shared).original_capacity_repr;
|
|
original_capacity = original_capacity_from_repr(original_capacity_repr);
|
|
|
|
// First, try to reclaim the buffer. This is possible if the current
|
|
// handle is the only outstanding handle pointing to the buffer.
|
|
if (*shared).is_unique() {
|
|
// This is the only handle to the buffer. It can be reclaimed.
|
|
// However, before doing the work of copying data, check to make
|
|
// sure that the vector has enough capacity.
|
|
let v = &mut (*shared).vec;
|
|
|
|
if v.capacity() >= new_cap {
|
|
// The capacity is sufficient, reclaim the buffer
|
|
let ptr = v.as_mut_ptr();
|
|
|
|
ptr::copy(self.ptr.as_ptr(), ptr, len);
|
|
|
|
self.ptr = vptr(ptr);
|
|
self.cap = v.capacity();
|
|
|
|
return;
|
|
}
|
|
|
|
// The vector capacity is not sufficient. The reserve request is
|
|
// asking for more than the initial buffer capacity. Allocate more
|
|
// than requested if `new_cap` is not much bigger than the current
|
|
// capacity.
|
|
//
|
|
// There are some situations, using `reserve_exact` that the
|
|
// buffer capacity could be below `original_capacity`, so do a
|
|
// check.
|
|
new_cap = cmp::max(
|
|
cmp::max(v.capacity() << 1, new_cap),
|
|
original_capacity);
|
|
} else {
|
|
new_cap = cmp::max(new_cap, original_capacity);
|
|
}
|
|
}
|
|
|
|
// Create a new vector to store the data
|
|
let mut v = Vec::with_capacity(new_cap);
|
|
|
|
// Copy the bytes
|
|
v.extend_from_slice(self.as_ref());
|
|
|
|
// Release the shared handle. This must be done *after* the bytes are
|
|
// copied.
|
|
unsafe { release_shared(shared) };
|
|
|
|
// Update self
|
|
let data = (original_capacity_repr << ORIGINAL_CAPACITY_OFFSET) | KIND_VEC;
|
|
self.data = data as _;
|
|
self.ptr = vptr(v.as_mut_ptr());
|
|
self.len = v.len();
|
|
self.cap = v.capacity();
|
|
|
|
// Forget the vector handle
|
|
mem::forget(v);
|
|
}
|
|
/// Appends given bytes to this object.
|
|
///
|
|
/// If this `BytesMut` object has not enough capacity, it is resized first.
|
|
/// So unlike `put_slice` operation, `extend_from_slice` does not panic.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use bytes::BytesMut;
|
|
///
|
|
/// let mut buf = BytesMut::with_capacity(0);
|
|
/// buf.extend_from_slice(b"aaabbb");
|
|
/// buf.extend_from_slice(b"cccddd");
|
|
///
|
|
/// assert_eq!(b"aaabbbcccddd", &buf[..]);
|
|
/// ```
|
|
pub fn extend_from_slice(&mut self, extend: &[u8]) {
|
|
self.reserve(extend.len());
|
|
self.put_slice(extend);
|
|
}
|
|
|
|
/// Combine splitted BytesMut objects back as contiguous.
|
|
///
|
|
/// If `BytesMut` objects were not contiguous originally, they will be extended.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use bytes::BytesMut;
|
|
///
|
|
/// let mut buf = BytesMut::with_capacity(64);
|
|
/// buf.extend_from_slice(b"aaabbbcccddd");
|
|
///
|
|
/// let splitted = buf.split_off(6);
|
|
/// assert_eq!(b"aaabbb", &buf[..]);
|
|
/// assert_eq!(b"cccddd", &splitted[..]);
|
|
///
|
|
/// buf.unsplit(splitted);
|
|
/// assert_eq!(b"aaabbbcccddd", &buf[..]);
|
|
/// ```
|
|
pub fn unsplit(&mut self, other: BytesMut) {
|
|
if self.is_empty() {
|
|
*self = other;
|
|
return;
|
|
}
|
|
|
|
if let Err(other) = self.try_unsplit(other) {
|
|
self.extend_from_slice(other.as_ref());
|
|
}
|
|
}
|
|
|
|
// private
|
|
|
|
// For now, use a `Vec` to manage the memory for us, but we may want to
|
|
// change that in the future to some alternate allocator strategy.
|
|
//
|
|
// Thus, we don't expose an easy way to construct from a `Vec` since an
|
|
// internal change could make a simple pattern (`BytesMut::from(vec)`)
|
|
// suddenly a lot more expensive.
|
|
#[inline]
|
|
pub(crate) fn from_vec(mut vec: Vec<u8>) -> BytesMut {
|
|
let ptr = vptr(vec.as_mut_ptr());
|
|
let len = vec.len();
|
|
let cap = vec.capacity();
|
|
mem::forget(vec);
|
|
|
|
let original_capacity_repr = original_capacity_to_repr(cap);
|
|
let data = (original_capacity_repr << ORIGINAL_CAPACITY_OFFSET) | KIND_VEC;
|
|
|
|
BytesMut {
|
|
ptr,
|
|
len,
|
|
cap,
|
|
data: data as *mut _,
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn as_slice(&self) -> &[u8] {
|
|
unsafe {
|
|
slice::from_raw_parts(self.ptr.as_ptr(), self.len)
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn as_slice_mut(&mut self) -> &mut [u8] {
|
|
unsafe {
|
|
slice::from_raw_parts_mut(self.ptr.as_ptr(), self.len)
|
|
}
|
|
}
|
|
|
|
unsafe fn set_start(&mut self, start: usize) {
|
|
// Setting the start to 0 is a no-op, so return early if this is the
|
|
// case.
|
|
if start == 0 {
|
|
return;
|
|
}
|
|
|
|
debug_assert!(start <= self.cap);
|
|
|
|
let kind = self.kind();
|
|
|
|
if kind == KIND_VEC {
|
|
// Setting the start when in vec representation is a little more
|
|
// complicated. First, we have to track how far ahead the
|
|
// "start" of the byte buffer from the beginning of the vec. We
|
|
// also have to ensure that we don't exceed the maximum shift.
|
|
let (mut pos, prev) = self.get_vec_pos();
|
|
pos += start;
|
|
|
|
if pos <= MAX_VEC_POS {
|
|
self.set_vec_pos(pos, prev);
|
|
} else {
|
|
// The repr must be upgraded to ARC. This will never happen
|
|
// on 64 bit systems and will only happen on 32 bit systems
|
|
// when shifting past 134,217,727 bytes. As such, we don't
|
|
// worry too much about performance here.
|
|
self.promote_to_shared(/*ref_count = */1);
|
|
}
|
|
}
|
|
|
|
// Updating the start of the view is setting `ptr` to point to the
|
|
// new start and updating the `len` field to reflect the new length
|
|
// of the view.
|
|
self.ptr = vptr(self.ptr.as_ptr().offset(start as isize));
|
|
|
|
if self.len >= start {
|
|
self.len -= start;
|
|
} else {
|
|
self.len = 0;
|
|
}
|
|
|
|
self.cap -= start;
|
|
}
|
|
|
|
unsafe fn set_end(&mut self, end: usize) {
|
|
debug_assert_eq!(self.kind(), KIND_ARC);
|
|
assert!(end <= self.cap);
|
|
|
|
self.cap = end;
|
|
self.len = cmp::min(self.len, end);
|
|
}
|
|
|
|
fn try_unsplit(&mut self, other: BytesMut) -> Result<(), BytesMut> {
|
|
if other.is_empty() {
|
|
return Ok(());
|
|
}
|
|
|
|
let ptr = unsafe { self.ptr.as_ptr().offset(self.len as isize) };
|
|
if ptr == other.ptr.as_ptr() &&
|
|
self.kind() == KIND_ARC &&
|
|
other.kind() == KIND_ARC &&
|
|
self.data == other.data
|
|
{
|
|
// Contiguous blocks, just combine directly
|
|
self.len += other.len;
|
|
self.cap += other.cap;
|
|
Ok(())
|
|
} else {
|
|
Err(other)
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn kind(&self) -> usize {
|
|
self.data as usize & KIND_MASK
|
|
}
|
|
|
|
unsafe fn promote_to_shared(&mut self, ref_cnt: usize) {
|
|
debug_assert_eq!(self.kind(), KIND_VEC);
|
|
debug_assert!(ref_cnt == 1 || ref_cnt == 2);
|
|
|
|
let original_capacity_repr =
|
|
(self.data as usize & ORIGINAL_CAPACITY_MASK) >> ORIGINAL_CAPACITY_OFFSET;
|
|
|
|
// The vec offset cannot be concurrently mutated, so there
|
|
// should be no danger reading it.
|
|
let off = (self.data as usize) >> VEC_POS_OFFSET;
|
|
|
|
// First, allocate a new `Shared` instance containing the
|
|
// `Vec` fields. It's important to note that `ptr`, `len`,
|
|
// and `cap` cannot be mutated without having `&mut self`.
|
|
// This means that these fields will not be concurrently
|
|
// updated and since the buffer hasn't been promoted to an
|
|
// `Arc`, those three fields still are the components of the
|
|
// vector.
|
|
let shared = Box::new(Shared {
|
|
vec: rebuild_vec(self.ptr.as_ptr(), self.len, self.cap, off),
|
|
original_capacity_repr,
|
|
ref_count: AtomicUsize::new(ref_cnt),
|
|
});
|
|
|
|
let shared = Box::into_raw(shared);
|
|
|
|
// The pointer should be aligned, so this assert should
|
|
// always succeed.
|
|
debug_assert_eq!(shared as usize & KIND_MASK, KIND_ARC);
|
|
|
|
self.data = shared as _;
|
|
}
|
|
|
|
/// Makes an exact shallow clone of `self`.
|
|
///
|
|
/// The kind of `self` doesn't matter, but this is unsafe
|
|
/// because the clone will have the same offsets. You must
|
|
/// be sure the returned value to the user doesn't allow
|
|
/// two views into the same range.
|
|
#[inline]
|
|
unsafe fn shallow_clone(&mut self) -> BytesMut {
|
|
if self.kind() == KIND_ARC {
|
|
increment_shared(self.data);
|
|
ptr::read(self)
|
|
} else {
|
|
self.promote_to_shared(/*ref_count = */2);
|
|
ptr::read(self)
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
unsafe fn get_vec_pos(&mut self) -> (usize, usize) {
|
|
debug_assert_eq!(self.kind(), KIND_VEC);
|
|
|
|
let prev = self.data as usize;
|
|
(prev >> VEC_POS_OFFSET, prev)
|
|
}
|
|
|
|
#[inline]
|
|
unsafe fn set_vec_pos(&mut self, pos: usize, prev: usize) {
|
|
debug_assert_eq!(self.kind(), KIND_VEC);
|
|
debug_assert!(pos <= MAX_VEC_POS);
|
|
|
|
self.data = ((pos << VEC_POS_OFFSET) | (prev & NOT_VEC_POS_MASK)) as *mut _;
|
|
}
|
|
}
|
|
|
|
impl Drop for BytesMut {
|
|
fn drop(&mut self) {
|
|
let kind = self.kind();
|
|
|
|
if kind == KIND_VEC {
|
|
unsafe {
|
|
let (off, _) = self.get_vec_pos();
|
|
|
|
// Vector storage, free the vector
|
|
let _ = rebuild_vec(self.ptr.as_ptr(), self.len, self.cap, off);
|
|
}
|
|
} else if kind == KIND_ARC {
|
|
unsafe { release_shared(self.data as _) };
|
|
}
|
|
}
|
|
}
|
|
|
|
impl Buf for BytesMut {
|
|
#[inline]
|
|
fn remaining(&self) -> usize {
|
|
self.len()
|
|
}
|
|
|
|
#[inline]
|
|
fn bytes(&self) -> &[u8] {
|
|
self.as_slice()
|
|
}
|
|
|
|
#[inline]
|
|
fn advance(&mut self, cnt: usize) {
|
|
assert!(cnt <= self.remaining(), "cannot advance past `remaining`");
|
|
unsafe { self.set_start(cnt); }
|
|
}
|
|
|
|
fn to_bytes(&mut self) -> crate::Bytes {
|
|
self.split().freeze()
|
|
}
|
|
}
|
|
|
|
impl BufMut for BytesMut {
|
|
#[inline]
|
|
fn remaining_mut(&self) -> usize {
|
|
self.capacity() - self.len()
|
|
}
|
|
|
|
#[inline]
|
|
unsafe fn advance_mut(&mut self, cnt: usize) {
|
|
let new_len = self.len() + cnt;
|
|
assert!(new_len <= self.cap);
|
|
self.len = new_len;
|
|
}
|
|
|
|
#[inline]
|
|
unsafe fn bytes_mut(&mut self) -> &mut [u8] {
|
|
slice::from_raw_parts_mut(self.ptr.as_ptr().offset(self.len as isize), self.cap)
|
|
}
|
|
|
|
#[inline]
|
|
fn put_slice(&mut self, src: &[u8]) {
|
|
assert!(self.remaining_mut() >= src.len());
|
|
|
|
let len = src.len();
|
|
|
|
unsafe {
|
|
self.bytes_mut()[..len].copy_from_slice(src);
|
|
self.advance_mut(len);
|
|
}
|
|
}
|
|
}
|
|
|
|
impl AsRef<[u8]> for BytesMut {
|
|
#[inline]
|
|
fn as_ref(&self) -> &[u8] {
|
|
self.as_slice()
|
|
}
|
|
}
|
|
|
|
impl Deref for BytesMut {
|
|
type Target = [u8];
|
|
|
|
#[inline]
|
|
fn deref(&self) -> &[u8] {
|
|
self.as_ref()
|
|
}
|
|
}
|
|
|
|
impl AsMut<[u8]> for BytesMut {
|
|
fn as_mut(&mut self) -> &mut [u8] {
|
|
self.as_slice_mut()
|
|
}
|
|
}
|
|
|
|
impl DerefMut for BytesMut {
|
|
#[inline]
|
|
fn deref_mut(&mut self) -> &mut [u8] {
|
|
self.as_mut()
|
|
}
|
|
}
|
|
|
|
impl<'a> From<&'a [u8]> for BytesMut {
|
|
fn from(src: &'a [u8]) -> BytesMut {
|
|
BytesMut::from_vec(src.to_vec())
|
|
}
|
|
}
|
|
|
|
impl<'a> From<&'a str> for BytesMut {
|
|
fn from(src: &'a str) -> BytesMut {
|
|
BytesMut::from(src.as_bytes())
|
|
}
|
|
}
|
|
|
|
impl PartialEq for BytesMut {
|
|
fn eq(&self, other: &BytesMut) -> bool {
|
|
self.as_slice() == other.as_slice()
|
|
}
|
|
}
|
|
|
|
impl PartialOrd for BytesMut {
|
|
fn partial_cmp(&self, other: &BytesMut) -> Option<cmp::Ordering> {
|
|
self.as_slice().partial_cmp(other.as_slice())
|
|
}
|
|
}
|
|
|
|
impl Ord for BytesMut {
|
|
fn cmp(&self, other: &BytesMut) -> cmp::Ordering {
|
|
self.as_slice().cmp(other.as_slice())
|
|
}
|
|
}
|
|
|
|
impl Eq for BytesMut {
|
|
}
|
|
|
|
impl Default for BytesMut {
|
|
#[inline]
|
|
fn default() -> BytesMut {
|
|
BytesMut::new()
|
|
}
|
|
}
|
|
|
|
impl fmt::Debug for BytesMut {
|
|
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
fmt::Debug::fmt(&debug::BsDebug(&self.as_slice()), fmt)
|
|
}
|
|
}
|
|
|
|
impl hash::Hash for BytesMut {
|
|
fn hash<H>(&self, state: &mut H) where H: hash::Hasher {
|
|
let s: &[u8] = self.as_ref();
|
|
s.hash(state);
|
|
}
|
|
}
|
|
|
|
impl Borrow<[u8]> for BytesMut {
|
|
fn borrow(&self) -> &[u8] {
|
|
self.as_ref()
|
|
}
|
|
}
|
|
|
|
impl BorrowMut<[u8]> for BytesMut {
|
|
fn borrow_mut(&mut self) -> &mut [u8] {
|
|
self.as_mut()
|
|
}
|
|
}
|
|
|
|
impl fmt::Write for BytesMut {
|
|
#[inline]
|
|
fn write_str(&mut self, s: &str) -> fmt::Result {
|
|
if self.remaining_mut() >= s.len() {
|
|
self.put_slice(s.as_bytes());
|
|
Ok(())
|
|
} else {
|
|
Err(fmt::Error)
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn write_fmt(&mut self, args: fmt::Arguments<'_>) -> fmt::Result {
|
|
fmt::write(self, args)
|
|
}
|
|
}
|
|
|
|
impl Clone for BytesMut {
|
|
fn clone(&self) -> BytesMut {
|
|
BytesMut::from(&self[..])
|
|
}
|
|
}
|
|
|
|
impl IntoIterator for BytesMut {
|
|
type Item = u8;
|
|
type IntoIter = IntoIter<BytesMut>;
|
|
|
|
fn into_iter(self) -> Self::IntoIter {
|
|
IntoIter::new(self)
|
|
}
|
|
}
|
|
|
|
impl<'a> IntoIterator for &'a BytesMut {
|
|
type Item = &'a u8;
|
|
type IntoIter = core::slice::Iter<'a, u8>;
|
|
|
|
fn into_iter(self) -> Self::IntoIter {
|
|
self.as_ref().into_iter()
|
|
}
|
|
}
|
|
|
|
impl Extend<u8> for BytesMut {
|
|
fn extend<T>(&mut self, iter: T) where T: IntoIterator<Item = u8> {
|
|
let iter = iter.into_iter();
|
|
|
|
let (lower, _) = iter.size_hint();
|
|
self.reserve(lower);
|
|
|
|
for b in iter {
|
|
unsafe {
|
|
self.bytes_mut()[0] = b;
|
|
self.advance_mut(1);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a> Extend<&'a u8> for BytesMut {
|
|
fn extend<T>(&mut self, iter: T) where T: IntoIterator<Item = &'a u8> {
|
|
self.extend(iter.into_iter().map(|b| *b))
|
|
}
|
|
}
|
|
|
|
impl FromIterator<u8> for BytesMut {
|
|
fn from_iter<T: IntoIterator<Item = u8>>(into_iter: T) -> Self {
|
|
BytesMut::from_vec(Vec::from_iter(into_iter))
|
|
}
|
|
}
|
|
|
|
impl<'a> FromIterator<&'a u8> for BytesMut {
|
|
fn from_iter<T: IntoIterator<Item = &'a u8>>(into_iter: T) -> Self {
|
|
BytesMut::from_iter(into_iter.into_iter().map(|b| *b))
|
|
}
|
|
}
|
|
|
|
/*
|
|
*
|
|
* ===== Inner =====
|
|
*
|
|
*/
|
|
|
|
unsafe fn increment_shared(ptr: *mut Shared) {
|
|
let old_size = (*ptr).ref_count.fetch_add(1, Ordering::Relaxed);
|
|
|
|
if old_size > isize::MAX as usize {
|
|
crate::abort();
|
|
}
|
|
}
|
|
|
|
unsafe fn release_shared(ptr: *mut Shared) {
|
|
// `Shared` storage... follow the drop steps from Arc.
|
|
if (*ptr).ref_count.fetch_sub(1, Ordering::Release) != 1 {
|
|
return;
|
|
}
|
|
|
|
// This fence is needed to prevent reordering of use of the data and
|
|
// deletion of the data. Because it is marked `Release`, the decreasing
|
|
// of the reference count synchronizes with this `Acquire` fence. This
|
|
// means that use of the data happens before decreasing the reference
|
|
// count, which happens before this fence, which happens before the
|
|
// deletion of the data.
|
|
//
|
|
// As explained in the [Boost documentation][1],
|
|
//
|
|
// > It is important to enforce any possible access to the object in one
|
|
// > thread (through an existing reference) to *happen before* deleting
|
|
// > the object in a different thread. This is achieved by a "release"
|
|
// > operation after dropping a reference (any access to the object
|
|
// > through this reference must obviously happened before), and an
|
|
// > "acquire" operation before deleting the object.
|
|
//
|
|
// [1]: (www.boost.org/doc/libs/1_55_0/doc/html/atomic/usage_examples.html)
|
|
atomic::fence(Ordering::Acquire);
|
|
|
|
// Drop the data
|
|
Box::from_raw(ptr);
|
|
}
|
|
|
|
impl Shared {
|
|
fn is_unique(&self) -> bool {
|
|
// The goal is to check if the current handle is the only handle
|
|
// that currently has access to the buffer. This is done by
|
|
// checking if the `ref_count` is currently 1.
|
|
//
|
|
// The `Acquire` ordering synchronizes with the `Release` as
|
|
// part of the `fetch_sub` in `release_shared`. The `fetch_sub`
|
|
// operation guarantees that any mutations done in other threads
|
|
// are ordered before the `ref_count` is decremented. As such,
|
|
// this `Acquire` will guarantee that those mutations are
|
|
// visible to the current thread.
|
|
self.ref_count.load(Ordering::Acquire) == 1
|
|
}
|
|
}
|
|
|
|
fn original_capacity_to_repr(cap: usize) -> usize {
|
|
let width = PTR_WIDTH - ((cap >> MIN_ORIGINAL_CAPACITY_WIDTH).leading_zeros() as usize);
|
|
cmp::min(width, MAX_ORIGINAL_CAPACITY_WIDTH - MIN_ORIGINAL_CAPACITY_WIDTH)
|
|
}
|
|
|
|
fn original_capacity_from_repr(repr: usize) -> usize {
|
|
if repr == 0 {
|
|
return 0;
|
|
}
|
|
|
|
1 << (repr + (MIN_ORIGINAL_CAPACITY_WIDTH - 1))
|
|
}
|
|
|
|
/*
|
|
#[test]
|
|
fn test_original_capacity_to_repr() {
|
|
assert_eq!(original_capacity_to_repr(0), 0);
|
|
|
|
let max_width = 32;
|
|
|
|
for width in 1..(max_width + 1) {
|
|
let cap = 1 << width - 1;
|
|
|
|
let expected = if width < MIN_ORIGINAL_CAPACITY_WIDTH {
|
|
0
|
|
} else if width < MAX_ORIGINAL_CAPACITY_WIDTH {
|
|
width - MIN_ORIGINAL_CAPACITY_WIDTH
|
|
} else {
|
|
MAX_ORIGINAL_CAPACITY_WIDTH - MIN_ORIGINAL_CAPACITY_WIDTH
|
|
};
|
|
|
|
assert_eq!(original_capacity_to_repr(cap), expected);
|
|
|
|
if width > 1 {
|
|
assert_eq!(original_capacity_to_repr(cap + 1), expected);
|
|
}
|
|
|
|
// MIN_ORIGINAL_CAPACITY_WIDTH must be bigger than 7 to pass tests below
|
|
if width == MIN_ORIGINAL_CAPACITY_WIDTH + 1 {
|
|
assert_eq!(original_capacity_to_repr(cap - 24), expected - 1);
|
|
assert_eq!(original_capacity_to_repr(cap + 76), expected);
|
|
} else if width == MIN_ORIGINAL_CAPACITY_WIDTH + 2 {
|
|
assert_eq!(original_capacity_to_repr(cap - 1), expected - 1);
|
|
assert_eq!(original_capacity_to_repr(cap - 48), expected - 1);
|
|
}
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn test_original_capacity_from_repr() {
|
|
assert_eq!(0, original_capacity_from_repr(0));
|
|
|
|
let min_cap = 1 << MIN_ORIGINAL_CAPACITY_WIDTH;
|
|
|
|
assert_eq!(min_cap, original_capacity_from_repr(1));
|
|
assert_eq!(min_cap * 2, original_capacity_from_repr(2));
|
|
assert_eq!(min_cap * 4, original_capacity_from_repr(3));
|
|
assert_eq!(min_cap * 8, original_capacity_from_repr(4));
|
|
assert_eq!(min_cap * 16, original_capacity_from_repr(5));
|
|
assert_eq!(min_cap * 32, original_capacity_from_repr(6));
|
|
assert_eq!(min_cap * 64, original_capacity_from_repr(7));
|
|
}
|
|
*/
|
|
|
|
unsafe impl Send for BytesMut {}
|
|
unsafe impl Sync for BytesMut {}
|
|
|
|
/*
|
|
*
|
|
* ===== PartialEq / PartialOrd =====
|
|
*
|
|
*/
|
|
|
|
impl PartialEq<[u8]> for BytesMut {
|
|
fn eq(&self, other: &[u8]) -> bool {
|
|
&**self == other
|
|
}
|
|
}
|
|
|
|
impl PartialOrd<[u8]> for BytesMut {
|
|
fn partial_cmp(&self, other: &[u8]) -> Option<cmp::Ordering> {
|
|
(**self).partial_cmp(other)
|
|
}
|
|
}
|
|
|
|
impl PartialEq<BytesMut> for [u8] {
|
|
fn eq(&self, other: &BytesMut) -> bool {
|
|
*other == *self
|
|
}
|
|
}
|
|
|
|
impl PartialOrd<BytesMut> for [u8] {
|
|
fn partial_cmp(&self, other: &BytesMut) -> Option<cmp::Ordering> {
|
|
other.partial_cmp(self)
|
|
}
|
|
}
|
|
|
|
impl PartialEq<str> for BytesMut {
|
|
fn eq(&self, other: &str) -> bool {
|
|
&**self == other.as_bytes()
|
|
}
|
|
}
|
|
|
|
impl PartialOrd<str> for BytesMut {
|
|
fn partial_cmp(&self, other: &str) -> Option<cmp::Ordering> {
|
|
(**self).partial_cmp(other.as_bytes())
|
|
}
|
|
}
|
|
|
|
impl PartialEq<BytesMut> for str {
|
|
fn eq(&self, other: &BytesMut) -> bool {
|
|
*other == *self
|
|
}
|
|
}
|
|
|
|
impl PartialOrd<BytesMut> for str {
|
|
fn partial_cmp(&self, other: &BytesMut) -> Option<cmp::Ordering> {
|
|
other.partial_cmp(self)
|
|
}
|
|
}
|
|
|
|
impl PartialEq<Vec<u8>> for BytesMut {
|
|
fn eq(&self, other: &Vec<u8>) -> bool {
|
|
*self == &other[..]
|
|
}
|
|
}
|
|
|
|
impl PartialOrd<Vec<u8>> for BytesMut {
|
|
fn partial_cmp(&self, other: &Vec<u8>) -> Option<cmp::Ordering> {
|
|
(**self).partial_cmp(&other[..])
|
|
}
|
|
}
|
|
|
|
impl PartialEq<BytesMut> for Vec<u8> {
|
|
fn eq(&self, other: &BytesMut) -> bool {
|
|
*other == *self
|
|
}
|
|
}
|
|
|
|
impl PartialOrd<BytesMut> for Vec<u8> {
|
|
fn partial_cmp(&self, other: &BytesMut) -> Option<cmp::Ordering> {
|
|
other.partial_cmp(self)
|
|
}
|
|
}
|
|
|
|
impl PartialEq<String> for BytesMut {
|
|
fn eq(&self, other: &String) -> bool {
|
|
*self == &other[..]
|
|
}
|
|
}
|
|
|
|
impl PartialOrd<String> for BytesMut {
|
|
fn partial_cmp(&self, other: &String) -> Option<cmp::Ordering> {
|
|
(**self).partial_cmp(other.as_bytes())
|
|
}
|
|
}
|
|
|
|
impl PartialEq<BytesMut> for String {
|
|
fn eq(&self, other: &BytesMut) -> bool {
|
|
*other == *self
|
|
}
|
|
}
|
|
|
|
impl PartialOrd<BytesMut> for String {
|
|
fn partial_cmp(&self, other: &BytesMut) -> Option<cmp::Ordering> {
|
|
other.partial_cmp(self)
|
|
}
|
|
}
|
|
|
|
impl<'a, T: ?Sized> PartialEq<&'a T> for BytesMut
|
|
where BytesMut: PartialEq<T>
|
|
{
|
|
fn eq(&self, other: &&'a T) -> bool {
|
|
*self == **other
|
|
}
|
|
}
|
|
|
|
impl<'a, T: ?Sized> PartialOrd<&'a T> for BytesMut
|
|
where BytesMut: PartialOrd<T>
|
|
{
|
|
fn partial_cmp(&self, other: &&'a T) -> Option<cmp::Ordering> {
|
|
self.partial_cmp(*other)
|
|
}
|
|
}
|
|
|
|
impl PartialEq<BytesMut> for &[u8] {
|
|
fn eq(&self, other: &BytesMut) -> bool {
|
|
*other == *self
|
|
}
|
|
}
|
|
|
|
impl PartialOrd<BytesMut> for &[u8] {
|
|
fn partial_cmp(&self, other: &BytesMut) -> Option<cmp::Ordering> {
|
|
other.partial_cmp(self)
|
|
}
|
|
}
|
|
|
|
impl PartialEq<BytesMut> for &str {
|
|
fn eq(&self, other: &BytesMut) -> bool {
|
|
*other == *self
|
|
}
|
|
}
|
|
|
|
impl PartialOrd<BytesMut> for &str {
|
|
fn partial_cmp(&self, other: &BytesMut) -> Option<cmp::Ordering> {
|
|
other.partial_cmp(self)
|
|
}
|
|
}
|
|
|
|
impl PartialEq<BytesMut> for Bytes {
|
|
fn eq(&self, other: &BytesMut) -> bool {
|
|
&other[..] == &self[..]
|
|
}
|
|
}
|
|
|
|
impl PartialEq<Bytes> for BytesMut {
|
|
fn eq(&self, other: &Bytes) -> bool {
|
|
&other[..] == &self[..]
|
|
}
|
|
}
|
|
|
|
fn vptr(ptr: *mut u8) -> NonNull<u8> {
|
|
if cfg!(debug_assertions) {
|
|
NonNull::new(ptr).expect("Vec pointer should be non-null")
|
|
} else {
|
|
unsafe { NonNull::new_unchecked(ptr) }
|
|
}
|
|
}
|
|
|
|
unsafe fn rebuild_vec(ptr: *mut u8, mut len: usize, mut cap: usize, off: usize) -> Vec<u8> {
|
|
let ptr = ptr.offset(-(off as isize));
|
|
len += off;
|
|
cap += off;
|
|
|
|
Vec::from_raw_parts(ptr, len, cap)
|
|
}
|
|
|
|
// ===== impl SharedVtable =====
|
|
|
|
static SHARED_VTABLE: Vtable = Vtable {
|
|
clone: shared_v_clone,
|
|
drop: shared_v_drop,
|
|
};
|
|
|
|
unsafe fn shared_v_clone(data: &AtomicPtr<()>, ptr: *const u8, len: usize) -> Bytes {
|
|
let shared = data.load(Ordering::Acquire) as *mut Shared;
|
|
increment_shared(shared);
|
|
|
|
let data = AtomicPtr::new(shared as _);
|
|
Bytes::with_vtable(ptr, len, data, &SHARED_VTABLE)
|
|
}
|
|
|
|
unsafe fn shared_v_drop(data: &mut AtomicPtr<()>, _ptr: *const u8, _len: usize) {
|
|
let shared = (*data.get_mut()) as *mut Shared;
|
|
release_shared(shared as *mut Shared);
|
|
}
|