1use std::{iter::FusedIterator, slice};
2
3use crate::{cfg, page, shard};
4
5/// An exclusive fused iterator over the items in a [`Slab`](crate::Slab).
6#[must_use = "iterators are lazy and do nothing unless consumed"]
7#[derive(Debug)]
8pub struct UniqueIter<'a, T, C: cfg::Config> {
9 pub(super) shards: shard::IterMut<'a, Option<T>, C>,
10 pub(super) pages: slice::Iter<'a, page::Shared<Option<T>, C>>,
11 pub(super) slots: Option<page::Iter<'a, T, C>>,
12}
13
14impl<'a, T, C: cfg::Config> Iterator for UniqueIter<'a, T, C> {
15 type Item = &'a T;
16
17 fn next(&mut self) -> Option<Self::Item> {
18 test_println!("UniqueIter::next");
19 loop {
20 test_println!("-> try next slot");
21 if let Some(item) = self.slots.as_mut().and_then(|slots| slots.next()) {
22 test_println!("-> found an item!");
23 return Some(item);
24 }
25
26 test_println!("-> try next page");
27 if let Some(page) = self.pages.next() {
28 test_println!("-> found another page");
29 self.slots = page.iter();
30 continue;
31 }
32
33 test_println!("-> try next shard");
34 if let Some(shard) = self.shards.next() {
35 test_println!("-> found another shard");
36 self.pages = shard.iter();
37 } else {
38 test_println!("-> all done!");
39 return None;
40 }
41 }
42 }
43}
44
45impl<T, C: cfg::Config> FusedIterator for UniqueIter<'_, T, C> {}
46