Crate sdd Copy item path

use sdd::{suspend, AtomicOwned, AtomicShared, Guard, Owned, Ptr, Shared, Tag};
use std::sync::atomic::Ordering::Relaxed;

// `atomic_shared` holds a strong reference to `17`.
let atomic_shared: AtomicShared<usize> = AtomicShared::new(17);

// `atomic_owned` owns `19`.
let atomic_owned: AtomicOwned<usize> = AtomicOwned::new(19);

// `guard` prevents the garbage collector from dropping reachable instances.
let guard = Guard::new();

// `ptr` cannot outlive `guard`.
let mut ptr: Ptr<usize> = atomic_shared.load(Relaxed, &guard);
assert_eq!(*ptr.as_ref().unwrap(), 17);

// `atomic_shared` can be tagged.
atomic_shared.update_tag_if(Tag::First, |p| p.tag() == Tag::None, Relaxed, Relaxed);

// `ptr` is not tagged, so CAS fails.
assert!(atomic_shared.compare_exchange(
    ptr,
    (Some(Shared::new(18)), Tag::First),
    Relaxed,
    Relaxed,
    &guard).is_err());

// `ptr` can be tagged.
ptr.set_tag(Tag::First);

// The ownership of the contained instance is transferred to the return value of CAS.
let prev: Shared<usize> = atomic_shared.compare_exchange(
    ptr,
    (Some(Shared::new(19)), Tag::Second),
    Relaxed,
    Relaxed,
    &guard).unwrap().0.unwrap();
assert_eq!(*prev, 17);

// `17` will be garbage-collected later.
drop(prev);

// `sdd::AtomicShared` can be converted into `sdd::Shared`.
let shared: Shared<usize> = atomic_shared.into_shared(Relaxed).unwrap();
assert_eq!(*shared, 19);

// `18` and `19` will be garbage-collected later.
drop(shared);
drop(atomic_owned);

// `17` is still valid as `guard` keeps the garbage collector from dropping it.
assert_eq!(*ptr.as_ref().unwrap(), 17);

// Execution of a closure can be deferred until all the current readers are gone.
guard.defer_execute(|| println!("deferred"));
drop(guard);

// `sdd::Owned` and `sdd::Shared` can be nested.
let shared_nested: Shared<Owned<Shared<usize>>> = Shared::new(Owned::new(Shared::new(20)));
assert_eq!(***shared_nested, 20);

// If the thread is expected to lie dormant for a while, call `suspend()` to allow
// others to reclaim the memory.
suspend();

use std::sync::atomic::Ordering::Relaxed;

use sdd::{AtomicShared, Guard, LinkedList, Shared};

#[derive(Default)]
struct L(AtomicShared<L>, usize);
impl LinkedList for L {
    fn link_ref(&self) -> &AtomicShared<L> {
        &self.0
    }
}

let guard = Guard::new();

let head: L = L::default();
let tail: Shared<L> = Shared::new(L(AtomicShared::null(), 1));

// A new entry is pushed.
assert!(head.push_back(tail.clone(), false, Relaxed, &guard).is_ok());
assert!(!head.is_marked(Relaxed));

// Users can mark a flag on an entry.
head.mark(Relaxed);
assert!(head.is_marked(Relaxed));

// `next_ptr` traverses the linked list.
let next_ptr = head.next_ptr(Relaxed, &guard);
assert_eq!(next_ptr.as_ref().unwrap().1, 1);

// Once `tail` is deleted, it becomes invisible.
tail.delete_self(Relaxed);
assert!(head.next_ptr(Relaxed, &guard).is_null());

use sdd::Queue;

let queue: Queue<usize> = Queue::default();

queue.push(1);
assert!(queue.push_if(2, |e| e.map_or(false, |x| **x == 1)).is_ok());
assert!(queue.push_if(3, |e| e.map_or(false, |x| **x == 1)).is_err());
assert_eq!(queue.pop().map(|e| **e), Some(1));
assert_eq!(queue.pop().map(|e| **e), Some(2));
assert!(queue.pop().is_none());

use sdd::Stack;

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

stack.push(1);
stack.push(2);
assert_eq!(stack.pop().map(|e| **e), Some(2));
assert_eq!(stack.pop().map(|e| **e), Some(1));
assert!(stack.pop().is_none());