From 3b4ef219664bed8dc020c0b85fda8642afeb9aad Mon Sep 17 00:00:00 2001
From: Ivan Enderlin <ivan@mnt.io>
Date: Thu, 29 Feb 2024 12:01:08 +0100
Subject: [PATCH] !drop

---
 crates/matrix-sdk/src/event_cache/store.rs | 36 ++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/crates/matrix-sdk/src/event_cache/store.rs b/crates/matrix-sdk/src/event_cache/store.rs
index 031528d30c4..82fdbc41589 100644
--- a/crates/matrix-sdk/src/event_cache/store.rs
+++ b/crates/matrix-sdk/src/event_cache/store.rs
@@ -500,6 +500,32 @@ pub mod experimental {
         }
     }
 
+    impl<T, const C: usize> Drop for LinkedChunk<T, C> {
+        fn drop(&mut self) {
+            // Take the latest chunk.
+            let mut current_chunk_ptr = self.last.or(Some(self.first));
+
+            // As long as we have another chunk…
+            while let Some(chunk_ptr) = current_chunk_ptr {
+                // Disconnect the chunk by updating `previous_chunk.next` pointer.
+                let previous_ptr = unsafe { chunk_ptr.as_ref() }.previous;
+
+                if let Some(mut previous_ptr) = previous_ptr {
+                    unsafe { previous_ptr.as_mut() }.next = None;
+                }
+
+                // Re-box the chunk, and let Rust does its job.
+                let _chunk_boxed = unsafe { Box::from_raw(chunk_ptr.as_ptr()) };
+
+                // Update the `current_chunk_ptr`.
+                current_chunk_ptr = previous_ptr;
+            }
+
+            // At this step, all chunks have been dropped, including
+            // `self.first`.
+        }
+    }
+
     /// The position of a chunk in a [`LinkedChunk`].
     ///
     /// 0 represents the latest chunk.
@@ -868,6 +894,16 @@ pub mod experimental {
             }
         }
 
+        #[test]
+        fn test_empty() {
+            let events = Events::<char, 3>::new();
+
+            assert_eq!(events.len(), 0);
+
+            // This test also ensures that `Drop` for `LinkedChunk` works when
+            // there is only one chunk.
+        }
+
         #[test]
         fn test_push_events() {
             let mut events = Events::<char, 3>::new();