Struct permit::Permit

pub struct Permit { /* private fields */ }

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 and wait for them to
// finish and drop their permits.
top_permit
    .revoke()
    .wait_subs_timeout(core::time::Duration::from_secs(3))
    .unwrap();

Implementations

impl Permit

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.

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.

pub fn is_revoked(&self) -> bool

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

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) -> &Self

Revokes this permit and all subordinate permits.

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 sleep(&self, duration: Duration) -> Result<(), PermitRevoked>

Waits until duration time passes or the permit is revoked.

Errors

Returns Err when the permit is revoked.

pub fn sleep_until(&self, deadline: Instant) -> Result<(), PermitRevoked>

Waits until deadline or the permit is revoked.

Errors

Returns Err when the permit is revoked.

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

Waits for all direct subordinate permits to drop.

Errors

Returns DeadlineExceeded when duration passes and the permit has a subordinate permit.

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

Waits for all direct subordinate permits to drop.

Errors

Returns DeadlineExceeded when deadline passes and the permit has a subordinate permit.

Trait Implementations

impl Clone for Permit

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Permit

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

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.

impl Future for Permit

type Output = ()

The type of value produced on completion.

fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>

Attempt to resolve the future to a final value, registering the current task for wakeup if the value is not yet available.