library/alloc/src/lib.rs

   1 //! # The Rust core allocation and collections library
   2 //!
   3 //! This library provides smart pointers and collections for managing
   4 //! heap-allocated values.
   5 //!
   6 //! This library, like libcore, normally doesn’t need to be used directly
   7 //! since its contents are re-exported in the [`std` crate](../std/index.html).
   8 //! Crates that use the `#![no_std]` attribute however will typically
   9 //! not depend on `std`, so they’d use this crate instead.
  10 //!
  11 //! ## Boxed values
  12 //!
  13 //! The [`Box`] type is a smart pointer type. There can only be one owner of a
  14 //! [`Box`], and the owner can decide to mutate the contents, which live on the
  15 //! heap.
  16 //!
  17 //! This type can be sent among threads efficiently as the size of a `Box` value
  18 //! is the same as that of a pointer. Tree-like data structures are often built
  19 //! with boxes because each node often has only one owner, the parent.
  20 //!
  21 //! ## Reference counted pointers
  22 //!
  23 //! The [`Rc`] type is a non-threadsafe reference-counted pointer type intended
  24 //! for sharing memory within a thread. An [`Rc`] pointer wraps a type, `T`, and
  25 //! only allows access to `&T`, a shared reference.
  26 //!
  27 //! This type is useful when inherited mutability (such as using [`Box`]) is too
  28 //! constraining for an application, and is often paired with the [`Cell`] or
  29 //! [`RefCell`] types in order to allow mutation.
  30 //!
  31 //! ## Atomically reference counted pointers
  32 //!
  33 //! The [`Arc`] type is the threadsafe equivalent of the [`Rc`] type. It
  34 //! provides all the same functionality of [`Rc`], except it requires that the
  35 //! contained type `T` is shareable. Additionally, [`Arc<T>`][`Arc`] is itself
  36 //! sendable while [`Rc<T>`][`Rc`] is not.
  37 //!
  38 //! This type allows for shared access to the contained data, and is often
  39 //! paired with synchronization primitives such as mutexes to allow mutation of
  40 //! shared resources.
  41 //!
  42 //! ## Collections
  43 //!
  44 //! Implementations of the most common general purpose data structures are
  45 //! defined in this library. They are re-exported through the
  46 //! [standard collections library](../std/collections/index.html).
  47 //!
  48 //! ## Heap interfaces
  49 //!
  50 //! The [`alloc`](alloc/index.html) module defines the low-level interface to the
  51 //! default global allocator. It is not compatible with the libc allocator API.
  52 //!
  53 //! [`Arc`]: sync
  54 //! [`Box`]: boxed
  55 //! [`Cell`]: core::cell
  56 //! [`Rc`]: rc
  57 //! [`RefCell`]: core::cell
  58
  59 #![allow(unused_attributes)]
  60 #![stable(feature = "alloc", since = "1.36.0")]
  61 #![doc(
  62     html_root_url = "https://doc.rust-lang.org/nightly/",
  63     html_playground_url = "https://play.rust-lang.org/",
  64     issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
  65     test(no_crate_inject, attr(allow(unused_variables), deny(warnings)))
  66 )]
  67 #![no_std]
  68 #![needs_allocator]
  69 #![warn(deprecated_in_future)]
  70 #![warn(missing_docs)]
  71 #![warn(missing_debug_implementations)]
  72 #![allow(explicit_outlives_requirements)]
  73 #![deny(unsafe_op_in_unsafe_fn)]
  74 #![feature(rustc_allow_const_fn_unstable)]
  75 #![cfg_attr(not(test), feature(generator_trait))]
  76 #![cfg_attr(test, feature(test))]
  77 #![cfg_attr(test, feature(new_uninit))]
  78 #![feature(allocator_api)]
  79 #![feature(array_chunks)]
  80 #![feature(array_methods)]
  81 #![feature(array_value_iter)]
  82 #![feature(array_windows)]
  83 #![feature(allow_internal_unstable)]
  84 #![feature(arbitrary_self_types)]
  85 #![feature(box_patterns)]
  86 #![feature(box_syntax)]
  87 #![feature(cfg_sanitize)]
  88 #![feature(cfg_target_has_atomic)]
  89 #![feature(coerce_unsized)]
  90 #![feature(const_btree_new)]
  91 #![feature(const_fn)]
  92 #![feature(cow_is_borrowed)]
  93 #![feature(const_cow_is_borrowed)]
  94 #![feature(dispatch_from_dyn)]
  95 #![feature(core_intrinsics)]
  96 #![feature(dropck_eyepatch)]
  97 #![feature(exact_size_is_empty)]
  98 #![feature(exclusive_range_pattern)]
  99 #![feature(extend_one)]
 100 #![feature(fmt_internals)]
 101 #![feature(fn_traits)]
 102 #![feature(fundamental)]
 103 #![feature(inplace_iteration)]
 104 #![feature(int_bits_const)]
 105 #![feature(lang_items)]
 106 #![feature(layout_for_ptr)]
 107 #![feature(maybe_uninit_ref)]
 108 #![feature(negative_impls)]
 109 #![feature(never_type)]
 110 #![feature(nll)]
 111 #![feature(nonnull_slice_from_raw_parts)]
 112 #![feature(auto_traits)]
 113 #![feature(or_patterns)]
 114 #![feature(pattern)]
 115 #![feature(ptr_internals)]
 116 #![feature(range_bounds_assert_len)]
 117 #![feature(raw_ref_op)]
 118 #![feature(rustc_attrs)]
 119 #![feature(receiver_trait)]
 120 #![cfg_attr(bootstrap, feature(min_const_generics))]
 121 #![feature(min_specialization)]
 122 #![feature(set_ptr_value)]
 123 #![feature(slice_ptr_get)]
 124 #![feature(slice_ptr_len)]
 125 #![feature(staged_api)]
 126 #![feature(str_internals)]
 127 #![feature(trusted_len)]
 128 #![feature(unboxed_closures)]
 129 #![feature(unicode_internals)]
 130 #![feature(unsafe_block_in_unsafe_fn)]
 131 #![feature(unsize)]
 132 #![feature(unsized_fn_params)]
 133 #![feature(allocator_internals)]
 134 #![feature(slice_partition_dedup)]
 135 #![feature(maybe_uninit_extra, maybe_uninit_slice, maybe_uninit_uninit_array)]
 136 #![feature(alloc_layout_extra)]
 137 #![feature(trusted_random_access)]
 138 #![feature(try_trait)]
 139 #![feature(type_alias_impl_trait)]
 140 #![feature(associated_type_bounds)]
 141 #![feature(slice_group_by)]
 142 #![feature(decl_macro)]
 143 // Allow testing this library
 144
 145 #[cfg(test)]
 146 #[macro_use]
 147 extern crate std;
 148 #[cfg(test)]
 149 extern crate test;
 150
 151 // Module with internal macros used by other modules (needs to be included before other modules).
 152 #[macro_use]
 153 mod macros;
 154
 155 // Heaps provided for low-level allocation strategies
 156
 157 pub mod alloc;
 158
 159 // Primitive types using the heaps above
 160
 161 // Need to conditionally define the mod from `boxed.rs` to avoid
 162 // duplicating the lang-items when building in test cfg; but also need
 163 // to allow code to have `use boxed::Box;` declarations.
 164 #[cfg(not(test))]
 165 pub mod boxed;
 166 #[cfg(test)]
 167 mod boxed {
 168     pub use std::boxed::Box;
 169 }
 170 pub mod borrow;
 171 pub mod collections;
 172 pub mod fmt;
 173 pub mod prelude;
 174 pub mod raw_vec;
 175 pub mod rc;
 176 pub mod slice;
 177 pub mod str;
 178 pub mod string;
 179 #[cfg(target_has_atomic = "ptr")]
 180 pub mod sync;
 181 #[cfg(target_has_atomic = "ptr")]
 182 pub mod task;
 183 #[cfg(test)]
 184 mod tests;
 185 pub mod vec;
 186
 187 #[doc(hidden)]
 188 #[unstable(feature = "liballoc_internals", issue = "none", reason = "implementation detail")]
 189 pub mod __export {
 190     pub use core::format_args;
 191 }