Struct wgpu_core::hub::Token

pub(crate) struct Token<'a, T: 'a> {
    level: PhantomData<&'a *const T>,
}

A zero-size permission token to lock some fields of Hub.

Access to a Token<T> grants permission to lock any field of Hub following the one of type [Registry<T, ...>], where “following” is as defined by the Access implementations.

Calling Token::root() returns a Token<Root>, which grants permission to lock any field. Dynamic checks ensure that each thread has at most one Token<Root> live at a time, in debug builds.

The locking methods on Registry<T, ...> take a &'t mut Token<A>, and return a fresh Token<'t, T> and a lock guard with lifetime 't, so the caller cannot access their Token<A> again until they have dropped both the Token<T> and the lock guard.

Tokens are !Send, so one thread can’t send its permissions to another.

Fields

level: PhantomData<&'a *const T>

Implementations

impl<'a, T> Token<'a, T>

pub(crate) fn new() -> Self

Return a new token for a locked field.

This should only be used by Registry locking methods.

impl Token<'static, Root>

pub fn root() -> Self

Return a Token<Root>, granting permission to lock any Hub field.

Debug builds check dynamically that each thread has at most one root token at a time.

Trait Implementations

impl<'a, T> Drop for Token<'a, T>

fn drop(&mut self)

Executes the destructor for this type.