allow &mut on index writer

src/index.rs

@@ -25,12 +25,12 @@ pub trait Writer {
     /// # Errors
     ///
     /// Will return `Err` if an IO error occurs.
-    fn insert_indirection(&self, key: &[u8], value: ValueHandle) -> std::io::Result<()>;
+    fn insert_indirection(&mut self, key: &[u8], value: ValueHandle) -> std::io::Result<()>;
 
     /// Finishes the write batch.
     ///
     /// # Errors
     ///
     /// Will return `Err` if an IO error occurs.
-    fn finish(&self) -> std::io::Result<()>;
+    fn finish(&mut self) -> std::io::Result<()>;
 }

src/mock.rs

@@ -47,11 +47,11 @@ impl From<MockIndex> for MockIndexWriter {
 }
 
 impl IndexWriter for MockIndexWriter {
-    fn insert_indirection(&self, key: &[u8], value: ValueHandle) -> std::io::Result<()> {
+    fn insert_indirection(&mut self, key: &[u8], value: ValueHandle) -> std::io::Result<()> {
         self.0.insert_indirection(key, value)
     }
 
-    fn finish(&self) -> std::io::Result<()> {
+    fn finish(&mut self) -> std::io::Result<()> {
         Ok(())
     }
 }

src/value_log.rs

@@ -319,7 +319,7 @@ impl<I: ExternalIndex + Clone + Send + Sync> ValueLog<I> {
     /// # Errors
     ///
     /// Will return `Err` if an IO error occurs.
-    pub fn rollover<W: IndexWriter>(&self, ids: &[u64], index_writer: &W) -> crate::Result<()> {
+    pub fn rollover<W: IndexWriter>(&self, ids: &[u64], index_writer: &mut W) -> crate::Result<()> {
         // IMPORTANT: Only allow 1 rollover at any given time
         let _guard = self.rollover_guard.lock().expect("lock is poisoned");
 

tests/basic_gc.rs

@@ -77,8 +77,8 @@ fn basic_gc() -> value_log::Result<()> {
 
     let ids = value_log.manifest.list_segment_ids();
 
-    let writer: MockIndexWriter = index.into();
-    value_log.rollover(&ids, &writer)?;
+    let mut writer: MockIndexWriter = index.into();
+    value_log.rollover(&ids, &mut writer)?;
     value_log.drop_stale_segments()?;
 
     {

tests/rollover_index_fail_finish.rs

@@ -44,11 +44,11 @@ impl From<DebugIndex> for DebugIndexWriter {
 }
 
 impl IndexWriter for DebugIndexWriter {
-    fn insert_indirection(&self, key: &[u8], value: ValueHandle) -> std::io::Result<()> {
+    fn insert_indirection(&mut self, key: &[u8], value: ValueHandle) -> std::io::Result<()> {
         self.0.insert_indirection(key, value)
     }
 
-    fn finish(&self) -> std::io::Result<()> {
+    fn finish(&mut self) -> std::io::Result<()> {
         Err(std::io::Error::new(std::io::ErrorKind::Other, "Oh no"))
     }
 }
@@ -94,7 +94,8 @@ fn rollover_index_fail_finish() -> value_log::Result<()> {
         0.0
     );
 
-    let result = value_log.rollover(&[0], &DebugIndexWriter(index.clone()));
+    let mut writer = DebugIndexWriter(index.clone());
+    let result = value_log.rollover(&[0], &mut writer);
     assert!(result.is_err());
 
     assert_eq!(