refactor: move iterator trait to parent mod

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

mini-lsm/src/iterators.rs

@@ -1,6 +1,19 @@
-pub mod impls;
 pub mod merge_iterator;
 pub mod two_merge_iterator;
 
+pub trait StorageIterator {
+    /// Get the current value.
+    fn value(&self) -> &[u8];
+
+    /// Get the current key.
+    fn key(&self) -> &[u8];
+
+    /// Check if the current iterator is valid.
+    fn is_valid(&self) -> bool;
+
+    /// Move to the next position.
+    fn next(&mut self) -> anyhow::Result<()>;
+}
+
 #[cfg(test)]
 mod tests;

mini-lsm/src/iterators/impls.rs

@@ -1,15 +0,0 @@
-use anyhow::Result;
-
-pub trait StorageIterator {
-    /// Get the current value.
-    fn value(&self) -> &[u8];
-
-    /// Get the current key.
-    fn key(&self) -> &[u8];
-
-    /// Check if the current iterator is valid.
-    fn is_valid(&self) -> bool;
-
-    /// Move to the next position.
-    fn next(&mut self) -> Result<()>;
-}

mini-lsm/src/iterators/merge_iterator.rs

@@ -4,7 +4,7 @@ use std::collections::BinaryHeap;
 
 use anyhow::Result;
 
-use super::impls::StorageIterator;
+use super::StorageIterator;
 
 struct HeapWrapper<I: StorageIterator>(pub usize, pub Box<I>);
 

mini-lsm/src/iterators/tests.rs

@@ -1,7 +1,7 @@
 use anyhow::Result;
 use bytes::Bytes;
 
-use super::impls::StorageIterator;
+use super::StorageIterator;
 
 pub mod merge_iterator_test;
 pub mod two_merge_iterator_test;

mini-lsm/src/iterators/two_merge_iterator.rs

@@ -1,6 +1,6 @@
 use anyhow::Result;
 
-use super::impls::StorageIterator;
+use super::StorageIterator;
 
 /// Merges two iterators of different types into one. If the two iterators have the same key, only
 /// produce the key once and prefer the entry from A.

mini-lsm/src/lsm_iterator.rs

@@ -3,9 +3,9 @@ use std::ops::Bound;
 use anyhow::Result;
 use bytes::Bytes;
 
-use crate::iterators::impls::StorageIterator;
 use crate::iterators::merge_iterator::MergeIterator;
 use crate::iterators::two_merge_iterator::TwoMergeIterator;
+use crate::iterators::StorageIterator;
 use crate::mem_table::MemTableIterator;
 use crate::table::SsTableIterator;
 

mini-lsm/src/lsm_storage.rs

@@ -7,9 +7,9 @@ use bytes::Bytes;
 use parking_lot::{Mutex, RwLock};
 
 use crate::block::Block;
-use crate::iterators::impls::StorageIterator;
 use crate::iterators::merge_iterator::MergeIterator;
 use crate::iterators::two_merge_iterator::TwoMergeIterator;
+use crate::iterators::StorageIterator;
 use crate::lsm_iterator::{FusedIterator, LsmIterator};
 use crate::mem_table::{map_bound, MemTable};
 use crate::table::{SsTable, SsTableBuilder, SsTableIterator};
@@ -126,6 +126,8 @@ impl LsmStorage {
         self.path.join(format!("{:05}.sst", id))
     }
 
+    /// 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<()> {

mini-lsm/src/mem_table.rs

@@ -7,7 +7,7 @@ use crossbeam_skiplist::map::Entry;
 use crossbeam_skiplist::SkipMap;
 use ouroboros::self_referencing;
 
-use crate::iterators::impls::StorageIterator;
+use crate::iterators::StorageIterator;
 use crate::table::SsTableBuilder;
 
 /// A basic mem-table based on crossbeam-skiplist

mini-lsm/src/mem_table/tests.rs

@@ -1,7 +1,7 @@
 use tempfile::tempdir;
 
 use super::MemTable;
-use crate::iterators::impls::StorageIterator;
+use crate::iterators::StorageIterator;
 use crate::table::{SsTableBuilder, SsTableIterator};
 
 #[test]

mini-lsm/src/table/iterator.rs

@@ -4,7 +4,7 @@ use anyhow::Result;
 
 use super::SsTable;
 use crate::block::BlockIterator;
-use crate::iterators::impls::StorageIterator;
+use crate::iterators::StorageIterator;
 
 /// An iterator over the contents of an SSTable.
 pub struct SsTableIterator {

mini-lsm/src/table/tests.rs

@@ -4,7 +4,7 @@ use bytes::Bytes;
 use tempfile::{tempdir, TempDir};
 
 use super::*;
-use crate::iterators::impls::StorageIterator;
+use crate::iterators::StorageIterator;
 use crate::table::SsTableBuilder;
 
 #[test]

mini-lsm/src/tests/day4_tests.rs

@@ -3,7 +3,7 @@ use std::ops::Bound;
 use bytes::Bytes;
 use tempfile::tempdir;
 
-use crate::iterators::impls::StorageIterator;
+use crate::iterators::StorageIterator;
 
 fn as_bytes(x: &[u8]) -> Bytes {
     Bytes::copy_from_slice(x)