Struct TokenCell 

pub struct TokenCell<T: ?Sized, Token: TokenTrait> { /* private fields */ }

A Cell that shifts the management of access permissions to its inner value onto a Token.

Implementations

impl<T: ?Sized, Token: TokenTrait> TokenCell<T, Token>

pub const fn get_mut(&mut self) -> &mut T

While cells are typically behind immutable references, obtaining a mutable reference to one is still proof of unique access.

impl<T: Sized, Token: TokenTrait> TokenCell<T, Token>

pub fn into_inner(self) -> T

Unwraps the value from the cell.

Full ownership of the cell is sufficient proof that the inner value can be recovered.

impl<T, Token: TokenTrait> TokenCell<T, Token>

pub fn new(value: T, token: &Token) -> Self

All calls to UnsafeTokenCellTrait or TokenCellTrait’s methods on the returned value MUST use the same instance of token as passed to this constructor.

Methods from Deref<Target = UnsafeCell<T>>

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

Replace the value in this UnsafeCell and return the old value.

Safety

The caller must take care to avoid aliasing and data races.

• It is Undefined Behavior to allow calls to race with any other access to the wrapped value.
• It is Undefined Behavior to call this while any other reference(s) to the wrapped value are alive.

Examples

use std::cell::UnsafeCell;

let uc = UnsafeCell::new(5);

let old = unsafe { uc.replace(10) };
assert_eq!(old, 5);

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

Gets a mutable pointer to the wrapped value.

This can be cast to a pointer of any kind. When creating (shared or mutable) references, you must uphold the aliasing rules; see the type-level docs for more discussion and caveats.

This is equivalent to casting self to a raw pointer and then casting that raw pointer to *mut T.

Examples

use std::cell::UnsafeCell;

let uc = UnsafeCell::new(5);

let five = uc.get();

pub fn get_mut(&mut self) -> &mut T

Returns a mutable reference to the underlying data.

This call borrows the UnsafeCell mutably (at compile-time) which guarantees that we possess the only reference.

Examples

use std::cell::UnsafeCell;

let mut c = UnsafeCell::new(5);
*c.get_mut() += 1;

assert_eq!(*c.get_mut(), 6);

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

Get a shared reference to the value within the UnsafeCell.

Safety

• It is Undefined Behavior to call this while any mutable reference to the wrapped value is alive.
• Mutating the wrapped value while the returned reference is alive is Undefined Behavior.

Examples

use std::cell::UnsafeCell;

let uc = UnsafeCell::new(5);

let val = unsafe { uc.as_ref_unchecked() };
assert_eq!(val, &5);

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

Get an exclusive reference to the value within the UnsafeCell.

Safety

• It is Undefined Behavior to call this while any other reference(s) to the wrapped value are alive.
• Mutating the wrapped value through other means while the returned reference is alive is Undefined Behavior.

Examples

use std::cell::UnsafeCell;

let uc = UnsafeCell::new(5);

unsafe { *uc.as_mut_unchecked() += 1; }
assert_eq!(uc.into_inner(), 6);

Trait Implementations

impl<T: ?Sized, Token: TokenTrait> Deref for TokenCell<T, Token>

type Target = UnsafeCell<T>

The resulting type after dereferencing.

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

Dereferences the value.

impl<T: ?Sized, Token: TokenTrait> DerefMut for TokenCell<T, Token>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<T: ?Sized, Token: TokenTrait> Sync for TokenCell<T, Token>

impl<T: ?Sized, Token: TokenTrait<ComparisonMaySpuriouslyEq = False>> TokenCellTrait<T, Token> for TokenCell<T, Token>

fn try_guard<'l>( &'l self, token: &'l Token, ) -> Result<TokenGuard<'l, T, Token>, <Token as TokenTrait>::ComparisonError>

Attempts to construct a guard which Derefs to the inner data, but also allows recovering the Token.

fn try_borrow<'l>( &'l self, token: &'l Token, ) -> Result<&'l T, Token::ComparisonError>

Attempts to borrow the inner data.

fn try_guard_mut<'l>( &'l self, token: &'l mut Token, ) -> Result<TokenGuardMut<'l, T, Token>, <Token as TokenTrait>::ComparisonError>

Attempts to construct a guard which DerefMuts to the inner data, but also allows recovering the Token.

fn try_borrow_mut<'l>( &'l self, token: &'l mut Token, ) -> Result<&'l mut T, Token::ComparisonError>

Attempts to borrow the inner data mutably.

fn borrow<'l>(&'l self, token: &'l Token) -> &'l T

where Token::ComparisonError: Debug,

Borrows the inner data, panicking if the wrong token was used as key.

fn borrow_mut<'l>(&'l self, token: &'l mut Token) -> &'l mut T

where Token::ComparisonError: Debug,

Borrows the inner data mutably, panicking if the wrong token was used as key.

fn map<'a, U, F: FnOnce(TokenGuard<'a, T, Token>) -> U>( &'a self, f: F, ) -> TokenMap<'a, T, U, F, Self, Token, False>

Constructs a lazy computation that can then be applied using the token.

fn map_mut<'a, U, F: FnOnce(TokenGuardMut<'a, T, Token>) -> U>( &'a self, f: F, ) -> TokenMapMut<'a, T, U, F, Self, Token, False>

Constructs a lazy computation that can then be applied using the token.

impl<T: ?Sized, Token: TokenTrait<ComparisonMaySpuriouslyEq = True>> UnsafeTokenCellTrait<T, Token> for TokenCell<T, Token>

unsafe fn try_guard<'l>( &'l self, token: &'l Token, ) -> Result<TokenGuard<'l, T, Token>, <Token as TokenTrait>::ComparisonError>

Attempts to construct a guard which Derefs to the inner data, but also allows recovering the Token.

unsafe fn try_borrow<'l>( &'l self, token: &'l Token, ) -> Result<&'l T, Token::ComparisonError>

Attempts to borrow the inner data.

unsafe fn try_guard_mut<'l>( &'l self, token: &'l mut Token, ) -> Result<TokenGuardMut<'l, T, Token>, <Token as TokenTrait>::ComparisonError>

Attempts to construct a guard which DerefMuts to the inner data, but also allows recovering the Token.

unsafe fn try_borrow_mut<'l>( &'l self, token: &'l mut Token, ) -> Result<&'l mut T, Token::ComparisonError>

Attempts to borrow the inner data mutably.

unsafe fn borrow<'l>(&'l self, token: &'l Token) -> &'l T

where Token::ComparisonError: Debug,

Borrows the inner data, panicking if the wrong token was used as key.

unsafe fn borrow_mut<'l>(&'l self, token: &'l mut Token) -> &'l mut T

where Token::ComparisonError: Debug,

Borrows the inner data mutably, panicking if the wrong token was used as key.

fn map<'a, U, F: FnOnce(TokenGuard<'a, T, Token>) -> U>( &'a self, f: F, ) -> TokenMap<'a, T, U, F, Self, Token, True>

Constructs a lazy computation that can then be applied using the token.

fn map_mut<'a, U, F: FnOnce(TokenGuardMut<'a, T, Token>) -> U>( &'a self, f: F, ) -> TokenMapMut<'a, T, U, F, Self, Token, True>

Constructs a lazy computation that can then be applied using the token.