Trait OnceExt

pub trait OnceExt: Sealed {
    type OnceState;

    // Required methods
    fn call_once_py_attached(&self, py: Python<'_>, f: impl FnOnce());
    fn call_once_force_py_attached(
        &self,
        py: Python<'_>,
        f: impl FnOnce(&Self::OnceState),
    );
}

Helper trait for Once to help avoid deadlocking when using a Once when attached to a Python thread.

Required Associated Types

type OnceState

The state of Once

Required Methods

fn call_once_py_attached(&self, py: Python<'_>, f: impl FnOnce())

Similar to call_once, but releases the Python GIL temporarily if blocking on another thread currently calling this Once.

fn call_once_force_py_attached( &self, py: Python<'_>, f: impl FnOnce(&Self::OnceState), )

Similar to call_once_force, but releases the Python GIL temporarily if blocking on another thread currently calling this Once.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl OnceExt for Once

type OnceState = OnceState

fn call_once_py_attached(&self, py: Python<'_>, f: impl FnOnce())

fn call_once_force_py_attached( &self, py: Python<'_>, f: impl FnOnce(&OnceState), )

impl OnceExt for Once

Available on crate feature parking_lot only.

type OnceState = OnceState

fn call_once_py_attached(&self, _py: Python<'_>, f: impl FnOnce())

fn call_once_force_py_attached( &self, _py: Python<'_>, f: impl FnOnce(&OnceState), )

Implementors