Crate tokenlock [−] [src]
Provides a Send
-able cell type whose contents can be accessed only via an
inforgeable token.
Examples
let mut token = Token::new(); let lock = TokenLock::new(&token, 1); assert_eq!(*lock.read(&token).unwrap(), 1); let mut guard = lock.write(&mut token).unwrap(); assert_eq!(*guard, 1); *guard = 2;
TokenLock
implements Send
and Sync
so it can be shared between threads,
but only the thread holding the original Token
can access its contents.
Token
cannot be cloned:
let lock = Arc::new(TokenLock::new(&token, 1)); let lock_1 = Arc::clone(&lock); thread::Builder::new().spawn(move || { let lock_1 = lock_1; let mut token_1 = token; // I have `Token` so I can get a mutable reference to the contents lock_1.write(&mut token_1).unwrap(); }).unwrap(); // can't access the contents; I no longer have `Token` // lock.write(&mut token).unwrap();
The lifetime of the returned reference is limited by both of the TokenLock
and Token
.
let mut token = Token::new(); let lock = TokenLock::new(&token, 1); let guard = lock.write(&mut token).unwrap(); drop(lock); // compile error: `guard` cannot outlive `TokenLock`
drop(token); // compile error: `guard` cannot outlive `Token`
It also prevents from forming a reference to the contained value when there already is a mutable reference to it:
let write_guard = lock.write(&mut token).unwrap(); let read_guard = lock.read(&token).unwrap(); // compile error
While allowing multiple immutable references:
let read_guard1 = lock.read(&token).unwrap(); let read_guard2 = lock.read(&token).unwrap();
Structs
Token |
An inforgeable token used to access the contents of a |
TokenLock |
A mutual exclusive primitive that can be accessed using a |
TokenRef |
Token that cannot be used to access the contents of a |