Vendor things

third-party/vendor/sharded-slab/src/iter.rs

@@ -0,0 +1,45 @@
+use std::{iter::FusedIterator, slice};
+
+use crate::{cfg, page, shard};
+
+/// An exclusive fused iterator over the items in a [`Slab`](crate::Slab).
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[derive(Debug)]
+pub struct UniqueIter<'a, T, C: cfg::Config> {
+    pub(super) shards: shard::IterMut<'a, Option<T>, C>,
+    pub(super) pages: slice::Iter<'a, page::Shared<Option<T>, C>>,
+    pub(super) slots: Option<page::Iter<'a, T, C>>,
+}
+
+impl<'a, T, C: cfg::Config> Iterator for UniqueIter<'a, T, C> {
+    type Item = &'a T;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        test_println!("UniqueIter::next");
+        loop {
+            test_println!("-> try next slot");
+            if let Some(item) = self.slots.as_mut().and_then(|slots| slots.next()) {
+                test_println!("-> found an item!");
+                return Some(item);
+            }
+
+            test_println!("-> try next page");
+            if let Some(page) = self.pages.next() {
+                test_println!("-> found another page");
+                self.slots = page.iter();
+                continue;
+            }
+
+            test_println!("-> try next shard");
+            if let Some(shard) = self.shards.next() {
+                test_println!("-> found another shard");
+                self.pages = shard.iter();
+            } else {
+                test_println!("-> all done!");
+                return None;
+            }
+        }
+    }
+}
+
+impl<T, C: cfg::Config> FusedIterator for UniqueIter<'_, T, C> {}