[storage] Fix values not invalidated after move #158 (#159)

* Update file_storage.rs

* Update file_storage.rs

* Update storage_impl.rs

* Update storage_impl.rs

* Update storage.rs

* Update pr.yaml

.github/workflows/pr.yaml

@@ -44,7 +44,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: taiki-e/install-action@cargo-llvm-cov
       - run: rustup component add llvm-tools-preview
-      - run: cargo llvm-cov --fail-uncovered-regions 83 --fail-uncovered-functions 0 --fail-uncovered-lines 0
+      - run: cargo llvm-cov --fail-uncovered-regions 84 --fail-uncovered-functions 0 --fail-uncovered-lines 0
 
   test:
     runs-on: ubuntu-latest

src/storage.rs

@@ -52,7 +52,7 @@ pub(crate) trait Storage<T: StorageImpl = Self>: StorageImpl<T> {
     fn remove(&mut self, index: i64) -> Result<(), DbError> {
         self.transaction();
         let position = self.record(index)?.position;
-        self.write(std::io::SeekFrom::Start(position), (-index).serialize())?;
+        self.invalidate_record(index, position)?;
         self.remove_index(index);
         self.commit()
     }

src/storage/file_storage.rs

@@ -614,6 +614,29 @@ mod tests {
         );
     }
 
+    #[test]
+    fn value_move_invalidates_original_position() {
+        let test_file =
+            TestFile::from("./file_storage-value_move_invalidates_original_position.agdb");
+
+        let index;
+
+        {
+            let mut storage = FileStorage::try_from(test_file.file_name().as_str()).unwrap();
+            index = storage.insert(&10_i64).unwrap();
+            storage.insert(&5_i64).unwrap();
+            storage.resize_value(index, 1).unwrap();
+            storage.remove(index).unwrap();
+        }
+
+        let mut storage = FileStorage::try_from(test_file.file_name().as_str()).unwrap();
+
+        assert_eq!(
+            storage.value::<i64>(index),
+            Err(DbError::Storage("index '1' not found".to_string()))
+        );
+    }
+
     #[test]
     fn value_size() {
         let test_file = TestFile::from("./file_storage-value_size.agdb");

src/storage/storage_impl.rs

@@ -93,19 +93,25 @@ pub(crate) trait StorageImpl<T = Self> {
     fn indexes_by_position(&self) -> Vec<i64>;
     fn insert_wal_record(&mut self, record: WriteAheadLogRecord) -> Result<(), DbError>;
 
+    fn invalidate_record(&mut self, index: i64, position: u64) -> Result<(), DbError> {
+        self.write(std::io::SeekFrom::Start(position), (-index).serialize())
+    }
+
     fn move_record_to_end(
         &mut self,
         index: i64,
         new_size: u64,
         offset: u64,
         record: &mut StorageRecord,
     ) -> Result<(), DbError> {
+        let old_position = record.position;
         *record = self.copy_record_to_end(
             record.position + std::mem::size_of::<StorageRecord>() as u64,
             core::cmp::min(record.size, offset),
             index,
             new_size,
         )?;
+        self.invalidate_record(index, old_position)?;
         *self.record_mut(index) = record.clone();
 
         Ok(())