Struct RefBox

pub struct RefBox<T: ?Sized> { /* private fields */ }

A smart pointer with many reference-counted weak references.

See the module documentation for more information.

Accessing the data behind the RefBox

See RefBox::try_borrow_mut, RefBox::try_borrow_mut_or_else and RefBox::try_access_mut.

Note: because all borrows are guarded by a single flag, only one borrow is possible at a time and all borrows are mutable.

Implementations

impl<T> RefBox<T>

pub fn new(value: T) -> Self

Creates a new RefBox reference counted pointer.

impl<T: ?Sized> RefBox<T>

pub fn try_borrow_mut(&self) -> Result<Borrow<'_, T>, BorrowError>

Tries to borrow the data mutably.

Returns

• Ok(Borrow) if the borrow was successful
• Err(BorrowError::Borrowed) if the data was already borrowed

pub fn try_borrow_mut_or_else<E>( &self, err_borrowed: impl FnOnce() -> E, ) -> Result<Borrow<'_, T>, E>

Tries to borrow the data mutably and returns a custom error if borrowing fails.

pub fn try_access_mut<R, F: FnOnce(&mut T) -> R>( &self, op: F, ) -> Result<R, BorrowError>

Provides access to the data through a closure.

If the data is already borrowed, the closure is not executed and an error is returned. Otherwise, the closure is executed and the output of the closure is returned.

Returns

• Ok(R) if the access was successful
• Err(BorrowError::Borrowed) if the data was already borrowed

pub fn downgrade(&self) -> Weak<T>

Creates a Weak reference to the data.

Panics

Panics if the number of Refs overflows u32::MAX.

See Self::try_downgrade for a version that does not panic.

pub fn try_downgrade(&self) -> Option<Weak<T>>

Tries to create a Weak pointer to the data.

Returns

• Some(Weak) if it was successful.
• None if the number of weak pointers overflowed u32::MAX.

pub fn weak_count(&self) -> u32

Returns the number of Weaks pointing to this RefBox.

pub unsafe fn get_unchecked(&self) -> &T

Returns an immutable reference to the data without checking if the data is already mutably borrowed.

Safety

Ensure there are no mutable references to T.

pub unsafe fn get_mut_unchecked(&mut self) -> &mut T

Returns a mutable reference to the data without checking if the data is already mutably borrowed.

Safety

Ensure there are no other references to T.

pub fn as_ptr(&self) -> *const T

Returns a raw pointer to T.

pub fn into_raw(self) -> *mut RefBoxHeap<T>

Turns the RefBox into a raw pointer.

pub unsafe fn from_raw(ptr: *mut RefBoxHeap<T>) -> Self

Creates a RefBox from a raw pointer.

Safety

Ensure ptr is a valid pointer to a RefBoxHeap<T> instance.

pub unsafe fn cast<U>(self) -> RefBox<U>

Casts a RefBox<T> to a RefBox<U>.

Safety

Ensure T can be safely cast to U.

Trait Implementations

impl<T: ?Sized + Debug> Debug for RefBox<T>

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

Tries to access the data and write a debug representation of it. If accessing fails, it only writes the pointer value.

impl<T: Default> Default for RefBox<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T: ?Sized> Drop for RefBox<T>

fn drop(&mut self)

Executes the destructor for this type.

impl<T> From<T> for RefBox<T>

fn from(val: T) -> Self

Converts to this type from the input type.

impl<T: ?Sized> PartialEq<RefBox<T>> for Weak<T>

fn eq(&self, other: &RefBox<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T: ?Sized> PartialEq<Weak<T>> for RefBox<T>

fn eq(&self, other: &Weak<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.