Struct rc_cell::RcCell

pub struct RcCell<T>(_);

The main attraction. Equivalent to Rc<RefCell<T>> but with one fewer type. Rc methods are reimplemented, and RefCell methods are gained by its Deref implementation.

All undocumented methods are equivalent to the Rc function of identical name.

Methods

impl<T> RcCell<T>

pub fn new(value: T) -> Self

pub fn try_unwrap(this: Self) -> Result<T, Self>

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

pub fn weak_count(&self) -> usize

pub fn strong_count(&self) -> usize

pub fn ptr_eq(&self, other: &Self) -> bool

pub fn swap_with(&self, other: &Self)

Like swap, but with another RcCell instead of a RefCell.

Methods from Deref<Target = RefCell<T>>

pub fn replace(&self, t: T) -> T

Replaces the wrapped value with a new one, returning the old value, without deinitializing either one.

This function corresponds to std::mem::replace.

Panics

Panics if the value is currently borrowed.

Examples

use std::cell::RefCell;
let cell = RefCell::new(5);
let old_value = cell.replace(6);
assert_eq!(old_value, 5);
assert_eq!(cell, RefCell::new(6));

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

Replaces the wrapped value with a new one computed from f, returning the old value, without deinitializing either one.

Panics

Panics if the value is currently borrowed.

Examples

use std::cell::RefCell;
let cell = RefCell::new(5);
let old_value = cell.replace_with(|&mut old| old + 1);
assert_eq!(old_value, 5);
assert_eq!(cell, RefCell::new(6));

pub fn swap(&self, other: &RefCell<T>)

Swaps the wrapped value of self with the wrapped value of other, without deinitializing either one.

This function corresponds to std::mem::swap.

Panics

Panics if the value in either RefCell is currently borrowed.

Examples

use std::cell::RefCell;
let c = RefCell::new(5);
let d = RefCell::new(6);
c.swap(&d);
assert_eq!(c, RefCell::new(6));
assert_eq!(d, RefCell::new(5));

pub fn borrow(&self) -> Ref<T>

Immutably borrows the wrapped value.

The borrow lasts until the returned Ref exits scope. Multiple immutable borrows can be taken out at the same time.

Panics

Panics if the value is currently mutably borrowed. For a non-panicking variant, use try_borrow.

Examples

use std::cell::RefCell;

let c = RefCell::new(5);

let borrowed_five = c.borrow();
let borrowed_five2 = c.borrow();

An example of panic:

use std::cell::RefCell;
use std::thread;

let result = thread::spawn(move || {
   let c = RefCell::new(5);
   let m = c.borrow_mut();

   let b = c.borrow(); // this causes a panic
}).join();

assert!(result.is_err());

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

Immutably borrows the wrapped value, returning an error if the value is currently mutably borrowed.

The borrow lasts until the returned Ref exits scope. Multiple immutable borrows can be taken out at the same time.

This is the non-panicking variant of borrow.

Examples

use std::cell::RefCell;

let c = RefCell::new(5);

{
    let m = c.borrow_mut();
    assert!(c.try_borrow().is_err());
}

{
    let m = c.borrow();
    assert!(c.try_borrow().is_ok());
}

pub fn borrow_mut(&self) -> RefMut<T>

Mutably borrows the wrapped value.

The borrow lasts until the returned RefMut or all RefMuts derived from it exit scope. The value cannot be borrowed while this borrow is active.

Panics

Panics if the value is currently borrowed. For a non-panicking variant, use try_borrow_mut.

Examples

use std::cell::RefCell;

let c = RefCell::new(5);

*c.borrow_mut() = 7;

assert_eq!(*c.borrow(), 7);

An example of panic:

use std::cell::RefCell;
use std::thread;

let result = thread::spawn(move || {
   let c = RefCell::new(5);
   let m = c.borrow();

   let b = c.borrow_mut(); // this causes a panic
}).join();

assert!(result.is_err());

pub fn try_borrow_mut(&self) -> Result<RefMut<T>, BorrowMutError>

Mutably borrows the wrapped value, returning an error if the value is currently borrowed.

The borrow lasts until the returned RefMut or all RefMuts derived from it exit scope. The value cannot be borrowed while this borrow is active.

This is the non-panicking variant of borrow_mut.

Examples

use std::cell::RefCell;

let c = RefCell::new(5);

{
    let m = c.borrow();
    assert!(c.try_borrow_mut().is_err());
}

assert!(c.try_borrow_mut().is_ok());

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

Returns a raw pointer to the underlying data in this cell.

Examples

use std::cell::RefCell;

let c = RefCell::new(5);

let ptr = c.as_ptr();

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

Immutably borrows the wrapped value, returning an error if the value is currently mutably borrowed.

Safety

Unlike RefCell::borrow, this method is unsafe because it does not return a Ref, thus leaving the borrow flag untouched. Mutably borrowing the RefCell while the reference returned by this method is alive is undefined behaviour.

Examples

use std::cell::RefCell;

let c = RefCell::new(5);

{
    let m = c.borrow_mut();
    assert!(unsafe { c.try_borrow_unguarded() }.is_err());
}

{
    let m = c.borrow();
    assert!(unsafe { c.try_borrow_unguarded() }.is_ok());
}

Trait Implementations

impl<T: Clone> Clone for RcCell<T>

fn clone(&self) -> RcCell<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for RcCell<T>

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

Formats the value using the given formatter.

impl<T: Default> Default for RcCell<T>

fn default() -> RcCell<T>

Returns the "default value" for a type.

impl<T> Deref for RcCell<T>

type Target = RefCell<T>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<T> Display for RcCell<T> where
    T: Display, 

fn fmt(&self, f: &mut Formatter) -> FmtResult

Formats the value using the given formatter.

impl<T: Eq> Eq for RcCell<T>

impl<T> From<Box<T>> for RcCell<T>

fn from(t: Box<T>) -> Self

Performs the conversion.

impl<T> From<T> for RcCell<T>

fn from(t: T) -> Self

Performs the conversion.

impl<T: Ord> Ord for RcCell<T>

fn cmp(&self, other: &RcCell<T>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

🔬 This is a nightly-only experimental API. (clamp)

Restrict a value to a certain interval.

impl<T: PartialEq> PartialEq<RcCell<T>> for RcCell<T>

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

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &RcCell<T>) -> bool

This method tests for !=.

impl<T: PartialOrd> PartialOrd<RcCell<T>> for RcCell<T>

fn partial_cmp(&self, other: &RcCell<T>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &RcCell<T>) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &RcCell<T>) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &RcCell<T>) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &RcCell<T>) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl<T> Pointer for RcCell<T>

fn fmt(&self, f: &mut Formatter) -> FmtResult

Formats the value using the given formatter.

impl<T> StructuralEq for RcCell<T>

impl<T> StructuralPartialEq for RcCell<T>