1 use std::{iter::FusedIterator, slice};
2 
3 use 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)]
8 pub 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 
14 impl<'a, T, C: cfg::Config> Iterator for UniqueIter<'a, T, C> {
15     type Item = &'a T;
16 
next(&mut self) -> Option<Self::Item>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 
45 impl<T, C: cfg::Config> FusedIterator for UniqueIter<'_, T, C> {}
46