Struct Stack

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pub struct Stack<T> { /* private fields */ }

Expand description

Stack is a lock-free concurrent last-in-first-out container.

Implementations§

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impl<T: 'static> Stack<T>

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pub fn push(&self, val: T) -> Shared<Entry<T>>

Pushes an instance of T.

Returns a Shared holding a strong reference to the newly pushed entry.

§Examples

use scc::Stack;

let stack: Stack<usize> = Stack::default();

assert_eq!(**stack.push(11), 11);

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pub fn push_if<F: FnMut(Option<&Entry<T>>) -> bool>( &self, val: T, cond: F, ) -> Result<Shared<Entry<T>>, T>

Pushes an instance of T if the newest entry satisfies the given condition.

§Errors

Returns an error along with the supplied instance if the condition is not met.

§Examples

use scc::Stack;

let stack: Stack<usize> = Stack::default();

stack.push(11);

assert!(stack.push_if(17, |e| e.map_or(false, |x| **x == 11)).is_ok());
assert!(stack.push_if(29, |e| e.map_or(false, |x| **x == 11)).is_err());

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pub fn peek<'g>(&self, guard: &'g Guard) -> Option<&'g Entry<T>>

Returns a guarded reference to the newest entry.

Returns None if the Stack is empty. The returned reference can survive as long as the associated Guard is alive.

§Examples

use scc::ebr::Guard;
use scc::Stack;

let stack: Stack<usize> = Stack::default();

assert!(stack.peek(&Guard::new()).is_none());

stack.push(37);
stack.push(3);

assert_eq!(**stack.peek(&Guard::new()).unwrap(), 3);

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impl<T> Stack<T>

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pub unsafe fn push_unchecked(&self, val: T) -> Shared<Entry<T>>

Pushes an instance of T without checking the lifetime of T.

Returns a Shared holding a strong reference to the newly pushed entry.

§Safety

T::drop can be run after the Stack is dropped, therefore it is safe only if T::drop does not access short-lived data or std::mem::needs_drop is false for T,

§Examples

use scc::Stack;

let hello = String::from("hello");
let stack: Stack<&str> = Stack::default();

assert_eq!(unsafe { **stack.push_unchecked(hello.as_str()) }, "hello");

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pub unsafe fn push_if_unchecked<F: FnMut(Option<&Entry<T>>) -> bool>( &self, val: T, cond: F, ) -> Result<Shared<Entry<T>>, T>

Pushes an instance of T if the newest entry satisfies the given condition without checking the lifetime of T.

§Errors

Returns an error along with the supplied instance if the condition is not met.

§Safety

T::drop can be run after the Stack is dropped, therefore it is safe only if T::drop does not access short-lived data or std::mem::needs_drop is false for T,

§Examples

use scc::Stack;

let hello = String::from("hello");
let stack: Stack<&str> = Stack::default();

assert!(unsafe { stack.push_if_unchecked(hello.as_str(), |e| e.is_none()).is_ok() });

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pub fn pop(&self) -> Option<Shared<Entry<T>>>

Pops the newest entry.

Returns None if the Stack is empty.

§Examples

use scc::Stack;

let stack: Stack<usize> = Stack::default();

stack.push(37);
stack.push(3);
stack.push(1);

assert_eq!(stack.pop().map(|e| **e), Some(1));
assert_eq!(stack.pop().map(|e| **e), Some(3));
assert_eq!(stack.pop().map(|e| **e), Some(37));
assert!(stack.pop().is_none());

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pub fn pop_all(&self) -> Self

Pops all the entries at once, and passes each one of the popped entries to the supplied closure.

§Examples

use scc::Stack;

let stack: Stack<usize> = Stack::default();

stack.push(37);
stack.push(3);

let popped = stack.pop_all();

stack.push(1);

assert_eq!(stack.pop().map(|e| **e), Some(1));
assert!(stack.pop().is_none());
assert!(stack.is_empty());

assert_eq!(popped.pop().map(|e| **e), Some(3));
assert_eq!(popped.pop().map(|e| **e), Some(37));
assert!(popped.pop().is_none());

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pub fn pop_if<F: FnMut(&Entry<T>) -> bool>( &self, cond: F, ) -> Result<Option<Shared<Entry<T>>>, Shared<Entry<T>>>

Pops the newest entry if the entry satisfies the given condition.

Returns None if the Stack is empty.

§Errors

Returns an error along with the newest entry if the given condition is not met.

§Examples

use scc::Stack;

let stack: Stack<usize> = Stack::default();

stack.push(3);
stack.push(1);

assert!(stack.pop_if(|v| **v == 3).is_err());
assert_eq!(stack.pop().map(|e| **e), Some(1));
assert_eq!(stack.pop_if(|v| **v == 3).ok().and_then(|e| e).map(|e| **e), Some(3));

assert!(stack.is_empty());

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pub fn peek_with<R, F: FnOnce(Option<&Entry<T>>) -> R>(&self, reader: F) -> R

Peeks the newest entry.

§Examples

use scc::Stack;

let stack: Stack<usize> = Stack::default();

assert!(stack.peek_with(|v| v.is_none()));

stack.push(37);
stack.push(3);

assert_eq!(stack.peek_with(|v| **v.unwrap()), 3);

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pub fn len(&self) -> usize

Returns the number of entries in the Stack.

This method iterates over all the entries in the Stack to count them, therefore its time complexity is O(N).

§Examples

use scc::Stack;

let stack: Stack<usize> = Stack::default();
assert_eq!(stack.len(), 0);

stack.push(7);
stack.push(11);
assert_eq!(stack.len(), 2);

stack.pop();
stack.pop();
assert_eq!(stack.len(), 0);

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pub fn is_empty(&self) -> bool

Returns true if the Stack is empty.

§Examples

use scc::Stack;

let stack: Stack<usize> = Stack::default();
assert!(stack.is_empty());

stack.push(7);
assert!(!stack.is_empty());

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pub fn iter<'g>(&self, guard: &'g Guard) -> Iter<'g, T> ⓘ

Returns an Iter.

§Examples

use scc::ebr::Guard;
use scc::Stack;

let stack: Stack<usize> = Stack::default();
assert_eq!(stack.iter(&Guard::new()).count(), 0);

stack.push(7);
stack.push(11);
stack.push(17);

let guard = Guard::new();
let mut iter = stack.iter(&guard);
assert_eq!(*iter.next().unwrap(), 17);
assert_eq!(*iter.next().unwrap(), 11);
assert_eq!(*iter.next().unwrap(), 7);
assert!(iter.next().is_none());