Struct MutRc 

pub struct MutRc<T>(/* private fields */);

A temporarily-mutable version of Rc.

MutRc<T> is essentially equivalent to Rc<RefCell<T>> except that it can be “finalized” into an Rc<T> once mutation is no longer needed. This operation preserves the original aliasing topology, and is useful for initializing aliasing structures that initially need mutability, but later can be converted to an immutable form.

All operations on MutRc are guaranteed to not panic.

Implementations

impl<T> MutRc<T>

pub fn new(value: T) -> Self

Creates a new, unaliased instance of MutRc<T> with the given initial value.

pub fn with<U, F: FnOnce(&T) -> U>(&self, f: F) -> Result<U, BorrowError>

Accesses the shared value immutably, optionally returning the result of the callback.

This operation can fail if the shared value is already borrowed mutably (i.e., if called from within MutRc::with_mut on the same shared value).

pub fn with_mut<U, F: FnOnce(&mut T) -> U>( &self, f: F, ) -> Result<U, MutateError>

Accesses the shared value mutably, optionally returning the result of the callback.

This operation can fail if the shared value is already borrowed (i.e., if called from within MutRc::with or MutRc::with_mut on the same shared value), or if there exists an aliasing Rc<T> returned by MutRc::finalize on the same shared value.

If recursion is needed, but mutation is not, consider using MutRc::with instead.

pub fn finalize(&self) -> Result<Rc<T>, BorrowError>

Finalizes the value into an (immutable) aliasing instance of Rc<T>. While this aliasing Rc<T> exists, all subsequent calls to MutRc::with_mut on the same shared value will fail.

This operation can fail if the shared value is already borrowed mutably (i.e., if called from within MutRc::with_mut on the same shared value).

pub fn get(&self) -> Result<T, BorrowError>

where T: Copy,

Gets a copy of the currently stored value.

pub fn get_clone(&self) -> Result<T, BorrowError>

where T: Clone,

Gets a clone of the currently stored value.

pub fn take(&self) -> Result<T, MutateError>

where T: Default,

Takes the currently stored value and replaces it with the default value.

pub fn replace(&self, value: T) -> Result<T, MutateError>

Replaces the currently stored value and returns the previous value.

pub fn set(&self, value: T) -> Result<(), MutateError>

Sets the currently stored value.

pub fn ptr_eq(this: &MutRc<T>, other: &MutRc<T>) -> bool

Checks if two instances of MutRc<T> are aliases to the same value.

pub fn downgrade(this: &Self) -> MutWeak<T>

Downgrades this MutRc into a MutWeak.

Trait Implementations

impl<T> Clone for MutRc<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for MutRc<T>

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

Formats the value using the given formatter.

impl<T: Default> Default for MutRc<T>

fn default() -> MutRc<T>

Returns the “default value” for a type.

impl<T> From<T> for MutRc<T>

fn from(value: T) -> Self

Converts to this type from the input type.