feat(ring buffer): implement RingBuffer::iter_mut()

crates/matrix-sdk-common/src/ring_buffer.rs

@@ -14,7 +14,7 @@
 
 use std::{
     collections::{
-        vec_deque::{Drain, Iter},
+        vec_deque::{Drain, Iter, IterMut},
         VecDeque,
     },
     num::NonZeroUsize,
@@ -88,6 +88,13 @@ impl<T> RingBuffer<T> {
         self.inner.iter()
     }
 
+    /// Returns a mutable iterator that provides elements in front-to-back
+    /// order, i.e. the same order you would get if you repeatedly called
+    /// pop().
+    pub fn iter_mut(&mut self) -> IterMut<'_, T> {
+        self.inner.iter_mut()
+    }
+
     /// Returns an iterator that drains its items.
     pub fn drain<R>(&mut self, range: R) -> Drain<'_, T>
     where
@@ -221,6 +228,24 @@ mod tests {
         assert_eq!(ring_buffer.remove(10), None);
     }
 
+    #[test]
+    fn test_iter() {
+        let mut ring_buffer = RingBuffer::new(NonZeroUsize::new(5).unwrap());
+
+        ring_buffer.push(1);
+        ring_buffer.push(2);
+        ring_buffer.push(3);
+
+        let as_vec = ring_buffer.iter().copied().collect::<Vec<_>>();
+        assert_eq!(as_vec, [1, 2, 3]);
+
+        let first_entry = ring_buffer.iter_mut().next().unwrap();
+        *first_entry = 42;
+
+        let as_vec = ring_buffer.iter().copied().collect::<Vec<_>>();
+        assert_eq!(as_vec, [42, 2, 3]);
+    }
+
     #[test]
     fn test_drain() {
         let mut ring_buffer = RingBuffer::new(NonZeroUsize::new(5).unwrap());