diff options
| -rw-r--r-- | library/core/src/alloc/mod.rs | 58 |
1 files changed, 27 insertions, 31 deletions
diff --git a/library/core/src/alloc/mod.rs b/library/core/src/alloc/mod.rs index aa841db045c..dcab6136ae8 100644 --- a/library/core/src/alloc/mod.rs +++ b/library/core/src/alloc/mod.rs @@ -49,26 +49,26 @@ impl fmt::Display for AllocError { /// An implementation of `Allocator` can allocate, grow, shrink, and deallocate arbitrary blocks of /// data described via [`Layout`][]. /// -/// `Allocator` is designed to be implemented on ZSTs, references, or smart pointers because having -/// an allocator like `MyAlloc([u8; N])` cannot be moved, without updating the pointers to the +/// `Allocator` is designed to be implemented on ZSTs, references, or smart pointers. +/// An allocator for `MyAlloc([u8; N])` cannot be moved, without updating the pointers to the /// allocated memory. /// -/// Unlike [`GlobalAlloc`][], zero-sized allocations are allowed in `Allocator`. If an underlying -/// allocator does not support this (like jemalloc) or return a null pointer (such as -/// `libc::malloc`), this must be caught by the implementation. +/// In contrast to [`GlobalAlloc`][], `Allocator` allows zero-sized allocations. If an underlying +/// allocator does not support this (like jemalloc) or responds by returning a null pointer +/// (such as `libc::malloc`), this must be caught by the implementation. /// /// ### Currently allocated memory /// -/// Some of the methods require that a memory block be *currently allocated* via an allocator. This -/// means that: +/// Some of the methods require that a memory block is *currently allocated* by an allocator. +/// This means that: +/// * the starting address for that memory block was previously +/// returned by [`allocate`], [`grow`], or [`shrink`], and +/// * the memory block has not subsequently been deallocated. /// -/// * the starting address for that memory block was previously returned by [`allocate`], [`grow`], or -/// [`shrink`], and -/// -/// * the memory block has not been subsequently deallocated, where blocks are either deallocated -/// directly by being passed to [`deallocate`] or were changed by being passed to [`grow`] or -/// [`shrink`] that returns `Ok`. If `grow` or `shrink` have returned `Err`, the passed pointer -/// remains valid. +/// A memory block is deallocated by a call to [`deallocate`], +/// or by a call to [`grow`] or [`shrink`] that returns `Ok`. +/// A call to `grow` or `shrink` that returns `Err`, +/// does not deallocate the memory block passed to it. /// /// [`allocate`]: Allocator::allocate /// [`grow`]: Allocator::grow @@ -77,32 +77,28 @@ impl fmt::Display for AllocError { /// /// ### Memory fitting /// -/// Some of the methods require that a layout *fit* a memory block. What it means for a layout to -/// "fit" a memory block means (or equivalently, for a memory block to "fit" a layout) is that the +/// Some of the methods require that a `layout` *fit* a memory block or vice versa. This means that the /// following conditions must hold: -/// -/// * The block must be allocated with the same alignment as [`layout.align()`], and -/// -/// * The provided [`layout.size()`] must fall in the range `min ..= max`, where: -/// - `min` is the size of the layout most recently used to allocate the block, and -/// - `max` is the latest actual size returned from [`allocate`], [`grow`], or [`shrink`]. +/// * the memory block must be *currently allocated* with alignment of [`layout.align()`], and +/// * [`layout.size()`] must fall in the range `min ..= max`, where: +/// - `min` is the size of the layout used to allocate the block, and +/// - `max` is the actual size returned from [`allocate`], [`grow`], or [`shrink`]. /// /// [`layout.align()`]: Layout::align /// [`layout.size()`]: Layout::size /// /// # Safety /// -/// * Memory blocks returned from an allocator that are [*currently allocated*] must point to -/// valid memory and retain their validity while they are [*currently allocated*] and the shorter -/// of: -/// - the borrow-checker lifetime of the allocator type itself. -/// - as long as at least one of the instance and all of its clones has not been dropped. +/// Memory blocks that are [*currently allocated*] by an allocator, +/// must point to valid memory, and retain their validity while until either: +/// - the memory block is deallocated, or +/// - the allocator is dropped. /// -/// * copying, cloning, or moving the allocator must not invalidate memory blocks returned from this -/// allocator. A copied or cloned allocator must behave like the same allocator, and +/// Copying, cloning, or moving the allocator must not invalidate memory blocks returned from it +/// A copied or cloned allocator must behave like the original allocator. /// -/// * any pointer to a memory block which is [*currently allocated*] may be passed to any other -/// method of the allocator. +/// A memory block which is [*currently allocated*] may be passed to +/// any method of the allocator that accepts such an argument. /// /// [*currently allocated*]: #currently-allocated-memory #[unstable(feature = "allocator_api", issue = "32838")] |