arc-slice 0.1.0

Shared memory slices
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133

//! A utility library for working with shared slices of memory.
//!
//! This crate provides efficient shared buffer implementations [`ArcSlice`] and [`ArcSliceMut`].
//!
//! # Examples
//!
//! ```rust
//! use arc_slice::{ArcSlice, ArcSliceMut};
//!
//! let mut bytes_mut: ArcSliceMut<[u8]> = ArcSliceMut::new();
//! bytes_mut.extend_from_slice(b"Hello world");
//!
//! let mut bytes: ArcSlice<[u8]> = bytes_mut.freeze();
//!
//! let a: ArcSlice<[u8]> = bytes.subslice(0..5);
//! assert_eq!(a, b"Hello");
//!
//! let b: ArcSlice<[u8]> = bytes.split_to(6);
//! assert_eq!(bytes, b"world");
//! assert_eq!(b, b"Hello ");
//! ```
//!
//! Depending on its [layout], [`ArcSlice`] can also support arbitrary buffers, e.g. shared memory,
//! and provides optional metadata that can be attached to the buffer.
//!
//! ```rust
//! use std::{
//!     fs::File,
//!     path::{Path, PathBuf},
//! };
//!
//! use arc_slice::{buffer::AsRefBuffer, layout::ArcLayout, ArcBytes};
//! use memmap2::Mmap;
//!
//! # fn main() -> std::io::Result<()> {
//! let path = Path::new("README.md").to_owned();
//! # #[cfg(not(miri))]
//! let file = File::open(&path)?;
//! # #[cfg(not(miri))]
//! let mmap = unsafe { Mmap::map(&file)? };
//! # #[cfg(miri)]
//! # let mmap = b"# arc-slice".to_vec();
//!
//! let buffer = AsRefBuffer(mmap);
//! let bytes: ArcBytes<ArcLayout<true>> = ArcBytes::from_buffer_with_metadata(buffer, path);
//! assert!(bytes.starts_with(b"# arc-slice"));
//! assert_eq!(bytes.metadata::<PathBuf>().unwrap(), Path::new("README.md"));
//! # Ok(())
//! # }
//! ```
//!
//! ## Features
//!
//! The crate provides the following optional features:
//! - `abort-on-refcount-overflow` (default): abort on refcount overflow; when disabled,
//!   the refcount saturates on overflow, leaking allocated memory (as in Linux kernel refcounting).
//! - `bstr`: implement slice traits for [`bstr`](::bstr) crate, allowing usage of `ArcSlice<BStr>`.
//! - `bytemuck`: use [`bytemuck::Zeroable`] as a bound for zero-initialization with
//!   [`ArcSliceMut::zeroed`].
//! - `bytes`: implement [`Buf`](::bytes::Buf) and [`BufMut`](::bytes::BufMut) traits for
//!   [`ArcSlice`] and [`ArcSliceMut`].
//! - `inlined`: enable [Small String Optimization] for [`ArcSlice`] via [`inlined::SmallArcSlice`].
//! - `oom-handling` (default): enable global [out-of-memory handling] with infallible allocation
//!   methods.
//! - `portable-atomic`: use [`portable_atomic`] instead of [`core::sync::atomic`].
//! - `portable-atomic-util`: implement traits for [`portable_atomic_util::Arc`] instead of
//!   [`alloc::sync::Arc`].
//! - `raw-buffer`: enable [`RawBuffer`](buffer::RawBuffer) and [`RawLayout`](layout::RawLayout).
//! - `serde`: implement [`Serialize`](::serde::Serialize) and [`Deserialize`](::serde::Deserialize)
//!   for [`ArcSlice`] and [`ArcSliceMut`].
//! - `std`: enable various `std` trait implementations and link to the standard library crate.
//!
//! Additionally, the default [layout] can be overridden with these features:
//! - `default-layout-any-buffer`: set [`ArcLayout`] `ANY_BUFFER` to `true`.
//! - `default-layout-static`: set [`ArcLayout`] `STATIC` to `true`.
//! - `default-layout-boxed-slice`: override default layout to
//!   [`BoxedSliceLayout`](layout::BoxedSliceLayout).
//! - `default-layout-vec`: override default layout to [`VecLayout`](layout::VecLayout).
//! - `default-layout-raw`: override default layout to [`RawLayout`](layout::RawLayout).
//! - `default-layout-mut-any-buffer`: set [`ArcLayout`] `ANY_BUFFER` to `true` for [`ArcSliceMut`].
//! - `default-layout-mut-vec`: override default layout to [`VecLayout`](layout::VecLayout) for
//!   [`ArcSliceMut`].
//!
//! [Small String Optimization]: https://cppdepend.com/blog/understanding-small-string-optimization-sso-in-stdstring/
//! [out-of-memory handling]: alloc::alloc::handle_alloc_error
//! [`ArcLayout`]: layout::ArcLayout
#![deny(missing_docs)]
#![deny(missing_debug_implementations)]
#![cfg_attr(docsrs, feature(doc_auto_cfg))]
#![no_std]
extern crate alloc;

#[doc(hidden)]
pub mod __private;
mod arc;
mod atomic;
#[cfg(feature = "bstr")]
mod bstr;
pub mod buffer;
#[cfg(feature = "bytes")]
mod bytes;
pub mod error;
#[cfg(feature = "inlined")]
pub mod inlined;
pub mod layout;
mod macros;
mod msrv;
#[cfg(feature = "serde")]
mod serde;
mod slice;
mod slice_mut;
mod utils;
mod vtable;

pub use crate::{
    slice::{ArcSlice, ArcSliceBorrow},
    slice_mut::ArcSliceMut,
};

/// An alias for `ArcSlice<[u8], L>`.
pub type ArcBytes<L = layout::DefaultLayout> = ArcSlice<[u8], L>;
/// An alias for `ArcSliceBorrow<[u8], L>`.
pub type ArcBytesBorrow<'a, L = layout::DefaultLayout> = ArcSliceBorrow<'a, [u8], L>;
/// An alias for `ArcSliceMut<[u8], L>`.
pub type ArcBytesMut<L = layout::DefaultLayoutMut, const UNIQUE: bool = true> =
    ArcSliceMut<[u8], L, UNIQUE>;
/// An alias for `ArcSlice<str, L>`.
pub type ArcStr<L = layout::DefaultLayout> = ArcSlice<str, L>;
/// An alias for `ArcSliceBorrow<str, L>`.
pub type ArcStrBorrow<'a, L = layout::DefaultLayout> = ArcSliceBorrow<'a, str, L>;
/// An alias for `ArcSliceMut<str, L>`.
pub type ArcStrMut<L = layout::DefaultLayoutMut, const UNIQUE: bool = true> =
    ArcSliceMut<str, L, UNIQUE>;