Enum crossbeam_deque::Steal

#[must_use]
pub enum Steal<T> {
    Empty,
    Success(T),
    Retry,
}

Possible outcomes of a steal operation.

Examples

There are lots of ways to chain results of steal operations together:

use crossbeam_deque::Steal::{self, Empty, Retry, Success};

let collect = |v: Vec<Steal<i32>>| v.into_iter().collect::<Steal<i32>>();

assert_eq!(collect(vec![Empty, Empty, Empty]), Empty);
assert_eq!(collect(vec![Empty, Retry, Empty]), Retry);
assert_eq!(collect(vec![Retry, Success(1), Empty]), Success(1));

assert_eq!(collect(vec![Empty, Empty]).or_else(|| Retry), Retry);
assert_eq!(collect(vec![Retry, Empty]).or_else(|| Success(1)), Success(1));

Variants

Empty

The queue was empty at the time of stealing.

Success(T)

At least one task was successfully stolen.

Retry

The steal operation needs to be retried.

Implementations

impl<T> Steal<T>

pub fn is_empty(&self) -> bool

Returns true if the queue was empty at the time of stealing.

Examples

use crossbeam_deque::Steal::{Empty, Retry, Success};

assert!(!Success(7).is_empty());
assert!(!Retry::<i32>.is_empty());

assert!(Empty::<i32>.is_empty());

pub fn is_success(&self) -> bool

Returns true if at least one task was stolen.

Examples

use crossbeam_deque::Steal::{Empty, Retry, Success};

assert!(!Empty::<i32>.is_success());
assert!(!Retry::<i32>.is_success());

assert!(Success(7).is_success());

pub fn is_retry(&self) -> bool

Returns true if the steal operation needs to be retried.

Examples

use crossbeam_deque::Steal::{Empty, Retry, Success};

assert!(!Empty::<i32>.is_retry());
assert!(!Success(7).is_retry());

assert!(Retry::<i32>.is_retry());

pub fn success(self) -> Option<T>

Returns the result of the operation, if successful.

Examples

use crossbeam_deque::Steal::{Empty, Retry, Success};

assert_eq!(Empty::<i32>.success(), None);
assert_eq!(Retry::<i32>.success(), None);

assert_eq!(Success(7).success(), Some(7));

pub fn or_else<F>(self, f: F) -> Steal<T> where
    F: FnOnce() -> Steal<T>, 

If no task was stolen, attempts another steal operation.

Returns this steal result if it is Success. Otherwise, closure f is invoked and then:

• If the second steal resulted in Success, it is returned.
• If both steals were unsuccessful but any resulted in Retry, then Retry is returned.
• If both resulted in None, then None is returned.

Examples

use crossbeam_deque::Steal::{Empty, Retry, Success};

assert_eq!(Success(1).or_else(|| Success(2)), Success(1));
assert_eq!(Retry.or_else(|| Success(2)), Success(2));

assert_eq!(Retry.or_else(|| Empty), Retry::<i32>);
assert_eq!(Empty.or_else(|| Retry), Retry::<i32>);

assert_eq!(Empty.or_else(|| Empty), Empty::<i32>);

Trait Implementations

impl<T: Clone> Clone for Steal<T>

fn clone(&self) -> Steal<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T> Debug for Steal<T>

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

Formats the value using the given formatter.

impl<T> FromIterator<Steal<T>> for Steal<T>

fn from_iter<I>(iter: I) -> Steal<T> where
    I: IntoIterator<Item = Steal<T>>, 

Consumes items until a Success is found and returns it.

If no Success was found, but there was at least one Retry, then returns Retry. Otherwise, Empty is returned.

impl<T: PartialEq> PartialEq<Steal<T>> for Steal<T>

fn eq(&self, other: &Steal<T>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Steal<T>) -> bool

This method tests for !=.

impl<T: Copy> Copy for Steal<T>

impl<T: Eq> Eq for Steal<T>

impl<T> StructuralEq for Steal<T>

impl<T> StructuralPartialEq for Steal<T>