add secret slice method

Cargo.toml

@@ -2,7 +2,7 @@
 name = "value-log"
 description = "Value log implementation for key-value separated LSM storage"
 license = "MIT OR Apache-2.0"
-version = "1.1.1"
+version = "1.2.0"
 edition = "2021"
 rust-version = "1.74.0"
 readme = "README.md"
@@ -27,7 +27,7 @@ min-max-heap = "1.3.0"
 path-absolutize = "3.1.1"
 quick_cache = { version = "0.6.5", default-features = false }
 rustc-hash = "2.0.0"
-serde = { version = "1.0.204", optional = true, features = ["derive"] }
+serde = { version = "1.0.215", optional = true, features = ["derive"] }
 tempfile = "3.12.0"
 xxhash-rust = { version = "0.8.12", features = ["xxh3"] }
 

src/key_range.rs

@@ -53,14 +53,10 @@ impl Encode for KeyRange {
 impl Decode for KeyRange {
     fn decode_from<R: Read>(reader: &mut R) -> Result<Self, DecodeError> {
         let key_min_len = reader.read_u16::<BigEndian>()?;
-        let mut key_min = vec![0; key_min_len.into()];
-        reader.read_exact(&mut key_min)?;
-        let key_min: UserKey = Slice::from(key_min);
+        let key_min: UserKey = Slice::from_reader(reader, key_min_len.into())?;
 
         let key_max_len = reader.read_u16::<BigEndian>()?;
-        let mut key_max = vec![0; key_max_len.into()];
-        reader.read_exact(&mut key_max)?;
-        let key_max: UserKey = Slice::from(key_max);
+        let key_max: UserKey = Slice::from_reader(reader, key_max_len.into())?;
 
         Ok(Self::new((key_min, key_max)))
     }

src/slice.rs

@@ -15,6 +15,22 @@ impl Slice {
     pub fn new(bytes: &[u8]) -> Self {
         Self::from(bytes)
     }
+
+    #[must_use]
+    #[doc(hidden)]
+    pub fn with_size(len: usize) -> Self {
+        // TODO: optimize this with byteview to remove the reallocation
+        let v = vec![0; len];
+        Self(v.into())
+    }
+
+    #[doc(hidden)]
+    pub fn from_reader<R: std::io::Read>(reader: &mut R, len: usize) -> std::io::Result<Self> {
+        let mut view = Self::with_size(len);
+        let builder = Arc::get_mut(&mut view.0).expect("we are the owner");
+        reader.read_exact(builder)?;
+        Ok(view)
+    }
 }
 
 impl std::borrow::Borrow<[u8]> for Slice {

tests/basic_kv.rs

@@ -23,30 +23,34 @@ fn basic_kv() -> value_log::Result<()> {
 
     let index = MockIndex::default();
 
-    let value_log = ValueLog::open(vl_path, Config::<NoCompressor>::default())?;
-
     let items = ["a", "b", "c", "d", "e"];
 
     {
-        let mut index_writer = MockIndexWriter(index.clone());
-        let mut writer = value_log.get_writer()?;
+        let value_log = ValueLog::open(vl_path, Config::<NoCompressor>::default())?;
 
-        for key in &items {
-            let value = key.repeat(10_000);
-            let value = value.as_bytes();
+        {
+            let mut index_writer = MockIndexWriter(index.clone());
+            let mut writer = value_log.get_writer()?;
 
-            let key = key.as_bytes();
+            for key in &items {
+                let value = key.repeat(10_000);
+                let value = value.as_bytes();
 
-            let vhandle = writer.get_next_value_handle();
-            index_writer.insert_indirect(key, vhandle, value.len() as u32)?;
+                let key = key.as_bytes();
 
-            writer.write(key, value)?;
-        }
+                let vhandle = writer.get_next_value_handle();
+                index_writer.insert_indirect(key, vhandle, value.len() as u32)?;
 
-        value_log.register_writer(writer)?;
+                writer.write(key, value)?;
+            }
+
+            value_log.register_writer(writer)?;
+        }
     }
 
     {
+        let value_log = ValueLog::open(vl_path, Config::<NoCompressor>::default())?;
+
         assert_eq!(1, value_log.segment_count());
 
         let segments = value_log.manifest.list_segments();
@@ -65,11 +69,11 @@ fn basic_kv() -> value_log::Result<()> {
             segment.len(),
             segment.scan().into_iter().flatten().count() as u64
         );
-    }
 
-    for (key, (vhandle, _)) in index.read().unwrap().iter() {
-        let item = value_log.get(vhandle)?.unwrap();
-        assert_eq!(&*item, &*key.repeat(10_000));
+        for (key, (vhandle, _)) in index.read().unwrap().iter() {
+            let item = value_log.get(vhandle)?.unwrap();
+            assert_eq!(&*item, &*key.repeat(10_000));
+        }
     }
 
     Ok(())