Struct scoped_arena::Scope

pub struct Scope<'arena, A: Allocator = Global> { /* fields omitted */ }

Scope associated with Scope allocator. Allows placing values on the scope returning reference bound to scope borrow. On drop scope drops all values placed onto it. On drop scope frees all memory allocated from it.

Implementations

impl Scope<'_, Global>

pub fn new() -> Self

Returns new instance of arena allocator based on [Global] allocator.

pub fn with_capacity(capacity: usize) -> Self

Returns new instance of arena allocator based on [Global] allocator with preallocated capacity in bytes.

impl<A> Scope<'_, A> where
    A: Allocator, 

pub fn new_in(alloc: A) -> Self

Returns new instance of arena allocator based on provided allocator.

pub fn with_capacity_in(capacity: usize, alloc: A) -> Self

Returns new instance of arena allocator based on provided allocator with preallocated capacity in bytes.

impl<A> Scope<'_, A> where
    A: Allocator, 

pub fn reset(&mut self)

pub fn alloc(&self, layout: Layout) -> NonNull<[u8]>

Allocates a block of memory. Returns a NonNull<u8> meeting the size and alignment guarantees of layout. The returned block contents should be considered uninitialized.

Returned block will be deallocated when scope is dropped.

pub fn try_alloc(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError>

Attempts to allocate a block of memory. On success, returns a NonNull<u8> meeting the size and alignment guarantees of layout. The returned block contents should be considered uninitialized.

Returned block will be deallocated when scope is dropped.

Errors

Returning Err indicates that memory is exhausted.

pub fn to_scope<T>(&self, value: T) -> &mut T

Move value onto the scope. Returns mutable reference to value with lifetime equal to scope borrow lifetime. Value on scope will be dropped when scope is dropped.

This method is as cheap as allocation if value does not needs dropping as reported by core::mem::needs_drop.

pub fn to_scope_with<F, T>(&self, f: F) -> &mut T where
    F: FnOnce() -> T, 

Places value returned from function onto the scope. Returns mutable reference to value with lifetime equal to scope borrow lifetime. Value on scope will be dropped when scope is dropped.

This method is as cheap as allocation if value does not needs dropping as reported by core::mem::needs_drop.

pub fn try_to_scope<T>(&self, value: T) -> Result<&mut T, (AllocError, T)>

Tries to move value onto the scope. On success, returns mutable reference to value with lifetime equal to scope borrow lifetime. Value on scope will be dropped when scope is dropped.

This method is as cheap as allocation if value does not needs dropping as reported by core::mem::needs_drop.

Errors

Returning Err indicates that memory is exhausted. Returning Err contains original value.

pub fn try_to_scope_with<F, T>(&self, f: F) -> Result<&mut T, (AllocError, F)> where
    F: FnOnce() -> T, 

Tries to place value return from function onto the scope. On success, returns mutable reference to value with lifetime equal to scope borrow lifetime. Value on scope will be dropped when scope is dropped.

This method is as cheap as allocation if value does not needs dropping as reported by core::mem::needs_drop.

Errors

Returning Err indicates that memory is exhausted. Returning Err contains original value.

pub fn to_scope_from_iter<T, I>(&self, iter: I) -> &mut [T] where
    I: IntoIterator<Item = T>, 

Move values from iterator onto the scope. Returns mutable reference to slice with lifetime equal to scope borrow lifetime. Values on scope will be dropped when scope is dropped.

This method is as cheap as allocation if value does not needs dropping as reported by core::mem::needs_drop.

This method allocates memory to hold iterator’s upper bound number of items. See core::iter::Iterator::size_hint. It will not consume more items. This method will always fail for unbound iterators.

pub fn try_to_scope_from_iter<T, I>(
    &self,
    iter: I
) -> Result<&mut [T], (AllocError, I::IntoIter)> where
    I: IntoIterator<Item = T>, 

Tries to move values from iterator onto the scope. On success, returns mutable reference to slice with lifetime equal to scope borrow lifetime. Values on scope will be dropped when scope is dropped.

This method is as cheap as allocation if value does not needs dropping as reported by core::mem::needs_drop.

This method allocates memory to hold iterator’s upper bound number of items. See core::iter::Iterator::size_hint. It will not consume more items. This method will always fail for unbound iterators.

Errors

Returning Err indicates that memory is exhausted. Returning Err contains original iterator.

pub fn total_memory_usage(&self) -> usize

Reports total memory allocated from underlying allocator by associated arena.

pub fn proxy_ref(&mut self) -> ScopeProxy<'_, &A>

Creates scope proxy bound to the scope. Any objects allocated through proxy will be attached to the scope. Returned proxy will use reference to the underlying allocator.

impl<A> Scope<'_, A> where
    A: Allocator + Clone, 

pub fn proxy(&mut self) -> ScopeProxy<'_, A>

Creates scope proxy bound to the scope. Any objects allocated through proxy will be attached to the scope. Returned proxy will use clone of the underlying allocator.

Trait Implementations

impl<A> Debug for Scope<'_, A> where
    A: Allocator, 

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<A> Drop for Scope<'_, A> where
    A: Allocator, 

fn drop(&mut self)

Executes the destructor for this type.