finish leveled compaction

Signed-off-by: Alex Chi <iskyzh@gmail.com>

mini-lsm-week-1/src/lsm_storage.rs

@@ -131,9 +131,6 @@ impl LsmStorage {
     }
 
     /// Persist data to disk.
-    ///
-    /// In day 3: flush the current memtable to disk as L0 SST.
-    /// In day 6: call `fsync` on WAL.
     pub fn sync(&self) -> Result<()> {
         let _flush_lock = self.flush_lock.lock();
 
@@ -221,9 +218,6 @@ impl LsmStorage {
 
         let iter = TwoMergeIterator::create(memtable_iter, table_iter)?;
 
-        Ok(FusedIterator::new(LsmIterator::new(
-            iter,
-            map_bound(upper),
-        )?))
+        Ok(FusedIterator::new(LsmIterator::new(iter, map_bound(upper))?))
     }
 }

mini-lsm-week-1/src/table.rs

@@ -61,27 +61,6 @@ impl BlockMeta {
 /// A file object.
 ///
 /// Before day 4, it should look like:
-///
-/// ```ignore
-/// pub struct FileObject(Bytes);
-///
-/// impl FileObject {
-///     pub fn read(&self, offset: u64, len: u64) -> Result<Vec<u8>> {
-///         Ok(self.0[offset as usize..(offset + len) as usize].to_vec())
-///    }
-///     pub fn size(&self) -> u64 {
-///         self.0.len() as u64
-///     }
-///
-///     pub fn create(_path: &Path, data: Vec<u8>) -> Result<Self> {
-///         Ok(FileObject(data.into()))
-///     }
-///
-///     pub fn open(_path: &Path) -> Result<Self> {
-///         unimplemented!()
-///     }
-/// }
-/// ```
 pub struct FileObject(File, u64);
 
 impl FileObject {