From 88ed1ddafd1f3cdf8201f453f06ddde98c868bb8 Mon Sep 17 00:00:00 2001
From: soruh <mail@soruh.de>
Date: Mon, 14 Aug 2023 17:42:59 +0200
Subject: [PATCH] fix Queue::last

---
 src/datastructures/queue.rs | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/datastructures/queue.rs b/src/datastructures/queue.rs
index 29f0e19..5cdfdbd 100644
--- a/src/datastructures/queue.rs
+++ b/src/datastructures/queue.rs
@@ -24,6 +24,7 @@ impl<T: FromBytes + FromZeroes + AsBytes + Unaligned + Clone + Copy> Slabable fo
     }
 }
 
+// TODO: make this return the bare Queue to avoid additional allocations
 impl<T: FromBytes + FromZeroes + AsBytes + Unaligned + Clone + Copy> Queue<T> {
     pub fn new<R>(transaction: &mut TransactionHandle<R>) -> FilePointer<Queue<T>> {
         let (queue, data) = transaction.allocate();
@@ -276,7 +277,13 @@ impl<T: FromBytes + FromZeroes + AsBytes + Unaligned + Clone + Copy> FilePointer
     }
 
     pub fn last(self, reader: &impl ReaderTrait) -> Option<T> {
-        self.get(reader, self.length(reader) - 1)
+        let length = self.length(reader);
+
+        if length == 0 {
+            None
+        } else {
+            self.get(reader, length - 1)
+        }
     }
 
     pub fn length(self, reader: &impl ReaderTrait) -> u64 {