Struct permit::Permit

pub struct Permit { /* fields omitted */ }

A struct for cancelling operations.

Use new_sub() to make a subordinate permit. Call revoke() to revoke a permit and its subordinate permits, recursively.

Example

Graceful shutdown:

let top_permit = permit::Permit::new();
// Start some worker threads.
for _ in 0..5 {
    let permit = top_permit.new_sub();
    std::thread::spawn(move || {
        while !permit.is_revoked() {
            // ...
        }
    });
}
wait_for_shutdown_signal();
// Revoke all thread permits.
top_permit.revoke();
// Give the threads time to finish
// and drop their permits.
let _ = top_permit.try_wait_for(
    core::time::Duration::from_secs(3));

Implementations

impl Permit

#[must_use]pub fn new() -> Self

Makes a new permit.

This permit is not subordinate to any other permit. It has no superior.

Dropping the permit revokes it and any subordinate permits.

#[must_use]pub fn new_sub(&self) -> Self

Make a new permit that is subordinate to this permit.

Call revoke() to revoke a permit and its subordinate permits, recursively.

Dropping the permit revokes it and any subordinate permits.

#[must_use]pub fn is_revoked(&self) -> bool

Returns true if revoke() has previously been called on this permit or any of its superiors.

#[must_use]pub fn ok(&self) -> Option<()>

Returns Some(()) if revoke() has not been called on this permit or any of its superiors.

pub fn revoke(&self)

Revokes this permit and all subordinate permits.

#[must_use]pub fn has_subs(&self) -> bool

Returns true if this permit has any subordinate permits that have not been dropped.

This includes direct subordinates and their subordinates, recursively.

pub fn wait(&self)

Wait indefinitely for all subordinate permits to drop.

This waits for all direct subordinates and their subordinates, recursively.

pub fn try_wait_for(&self, duration: Duration) -> Result<(), DeadlineExceeded>

Wait for all subordinate permits to drop.

This waits for all direct subordinates and their subordinates, recursively.

Errors

Returns DeadlineExceeded if the subordinate permits are not all dropped before duration passes.

pub fn try_wait_until(&self, deadline: Instant) -> Result<(), DeadlineExceeded>

Wait for all subordinate permits to drop.

This waits for all direct subordinates and their subordinates, recursively.

Errors

Returns DeadlineExceeded if the subordinate permits are not all dropped before deadline passes.

Trait Implementations

impl Clone for Permit

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Default for Permit

fn default() -> Self

Returns the “default value” for a type.

impl Drop for Permit

fn drop(&mut self)

Executes the destructor for this type.