refactor: relax generic bounds on CAS/index APIs

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cassadilia"
-version = "0.4.6"
+version = "0.4.7"
 edition = "2024"
 rust-version = "1.89.0"
 authors = ["0xdeafbeef"]

src/index/mod.rs

@@ -180,10 +180,6 @@ where
         Ok(index)
     }
 
-    pub fn read_state(&self) -> IndexReadGuard<'_, K> {
-        IndexReadGuard { inner: self.state.read() }
-    }
-
     pub fn checkpoint(&self, reason: CheckpointReason) -> Result<(), IndexError> {
         tracing::info!(?reason, "Starting checkpoint operation.");
 
@@ -356,6 +352,12 @@ where
     }
 }
 
+impl<K> Index<K> {
+    pub fn read_state(&self) -> IndexReadGuard<'_, K> {
+        IndexReadGuard { inner: self.state.read() }
+    }
+}
+
 impl<K: Debug> Debug for Index<K> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         let state_guard = self.state.read();
@@ -381,46 +383,10 @@ pub struct IndexReadGuard<'a, K> {
     inner: parking_lot::RwLockReadGuard<'a, IndexState<K>>,
 }
 
-impl<'a, K> IndexReadGuard<'a, K>
-where
-    K: Debug + Clone + Ord,
-{
-    /// Returns the item for the given key, if it exists.
-    pub fn get_item(&self, key: &K) -> Option<IndexStateItem> {
-        self.inner.key_to_hash.get(key).copied()
-    }
-
-    /// Returns the item for the given key, or an error if it is not present.
-    pub fn require_item(&self, key: &K) -> Result<IndexStateItem, IndexError> {
-        self.get_item(key).ok_or(IndexError::KeyNotFound { key: format!("{key:?}") })
-    }
-
-    /// Returns `true` if the index contains the specified key.
-    pub fn contains_key(&self, key: &K) -> bool {
-        self.inner.key_to_hash.contains_key(key)
-    }
-
-    /// Returns an iterator over all entries in ascending key order.
-    pub fn iter(&self) -> std::collections::btree_map::Iter<'_, K, IndexStateItem> {
-        self.inner.key_to_hash.iter()
-    }
-
-    /// Returns an iterator over entries within the specified key range, in ascending order.
-    /// The range may use a borrowed form of the key (e.g., `&str` for `String`).
-    pub fn range<T, R>(&self, range: R) -> std::collections::btree_map::Range<'_, K, IndexStateItem>
-    where
-        T: ?Sized + Ord,
-        K: Borrow<T> + Ord,
-        R: RangeBounds<T>,
-    {
-        self.inner.key_to_hash.range(range)
-    }
-
-    /// Returns a snapshot of the current key map.
-    /// Calls `clone` inside.
+impl<'a, K> IndexReadGuard<'a, K> {
     #[must_use]
-    pub fn keys_snapshot(&self) -> BTreeMap<K, IndexStateItem> {
-        self.inner.key_to_hash.clone()
+    pub fn stats(&self) -> DbStats {
+        self.inner.stats
     }
 
     /// Returns the number of keys in the index.
@@ -447,9 +413,57 @@ where
         self.inner.hash_to_ref_count.contains_key(hash)
     }
 
+    /// Returns an iterator over entries within the specified key range, in ascending order.
+    /// The range may use a borrowed form of the key (e.g., `&str` for `String`).
+    pub fn range<T, R>(&self, range: R) -> std::collections::btree_map::Range<'_, K, IndexStateItem>
+    where
+        T: ?Sized + Ord,
+        K: Borrow<T> + Ord,
+        R: RangeBounds<T>,
+    {
+        self.inner.key_to_hash.range(range)
+    }
+}
+
+impl<'a, K> IndexReadGuard<'a, K>
+where
+    K: Ord,
+{
+    /// Returns the item for the given key, if it exists.
+    pub fn get_item(&self, key: &K) -> Option<IndexStateItem> {
+        self.inner.key_to_hash.get(key).copied()
+    }
+
+    /// Returns `true` if the index contains the specified key.
+    pub fn contains_key(&self, key: &K) -> bool {
+        self.inner.key_to_hash.contains_key(key)
+    }
+
+    /// Returns an iterator over all entries in ascending key order.
+    pub fn iter(&self) -> std::collections::btree_map::Iter<'_, K, IndexStateItem> {
+        self.inner.key_to_hash.iter()
+    }
+}
+
+impl<'a, K> IndexReadGuard<'a, K>
+where
+    K: Debug + Ord,
+{
+    /// Returns the item for the given key, or an error if it is not present.
+    pub fn require_item(&self, key: &K) -> Result<IndexStateItem, IndexError> {
+        self.get_item(key).ok_or(IndexError::KeyNotFound { key: format!("{key:?}") })
+    }
+}
+
+impl<'a, K> IndexReadGuard<'a, K>
+where
+    K: Clone,
+{
+    /// Returns a snapshot of the current key map.
+    /// Calls `clone` inside.
     #[must_use]
-    pub fn stats(&self) -> DbStats {
-        self.inner.stats
+    pub fn keys_snapshot(&self) -> BTreeMap<K, IndexStateItem> {
+        self.inner.key_to_hash.clone()
     }
 }
 

src/index/state.rs

@@ -28,10 +28,7 @@ pub struct IndexStateItem {
     pub blob_size: u64,
 }
 
-impl<K> IndexState<K>
-where
-    K: Clone + Eq + Ord,
-{
+impl<K> IndexState<K> {
     pub fn new() -> Self {
         IndexState {
             key_to_hash: BTreeMap::new(),
@@ -57,6 +54,41 @@ where
         self.stats.index.serialized_size_bytes = index_file_size_bytes;
     }
 
+    pub(crate) fn increment_ref(&mut self, hash: &BlobHash) -> bool {
+        let entry = self.hash_to_ref_count.entry(*hash).or_default();
+        let was_zero = *entry == 0;
+        *entry += 1;
+        was_zero
+    }
+
+    pub(crate) fn decrement_ref(
+        &mut self,
+        hash_to_decrement: &BlobHash,
+    ) -> Result<Option<BlobHash>, IndexStateError> {
+        match self.hash_to_ref_count.get_mut(hash_to_decrement) {
+            Some(count) => {
+                if *count == 0 {
+                    return Err(IndexStateError::DecrementZeroRefCount {
+                        hash: *hash_to_decrement,
+                    });
+                }
+                *count -= 1;
+                if *count == 0 {
+                    self.hash_to_ref_count.remove(hash_to_decrement);
+                    Ok(Some(*hash_to_decrement))
+                } else {
+                    Ok(None)
+                }
+            }
+            None => Err(IndexStateError::HashNotFoundForDecrement { hash: *hash_to_decrement }),
+        }
+    }
+}
+
+impl<K> IndexState<K>
+where
+    K: Clone + Ord,
+{
     pub fn apply_logical_op(&mut self, op: &WalOp<K>) -> Result<Vec<BlobHash>, IndexStateError> {
         let mut unreferenced_hashes = Vec::new();
 
@@ -116,34 +148,4 @@ where
 
         Ok(unreferenced_hashes)
     }
-
-    pub(crate) fn increment_ref(&mut self, hash: &BlobHash) -> bool {
-        let entry = self.hash_to_ref_count.entry(*hash).or_default();
-        let was_zero = *entry == 0;
-        *entry += 1;
-        was_zero
-    }
-
-    pub(crate) fn decrement_ref(
-        &mut self,
-        hash_to_decrement: &BlobHash,
-    ) -> Result<Option<BlobHash>, IndexStateError> {
-        match self.hash_to_ref_count.get_mut(hash_to_decrement) {
-            Some(count) => {
-                if *count == 0 {
-                    return Err(IndexStateError::DecrementZeroRefCount {
-                        hash: *hash_to_decrement,
-                    });
-                }
-                *count -= 1;
-                if *count == 0 {
-                    self.hash_to_ref_count.remove(hash_to_decrement);
-                    Ok(Some(*hash_to_decrement))
-                } else {
-                    Ok(None)
-                }
-            }
-            None => Err(IndexStateError::HashNotFoundForDecrement { hash: *hash_to_decrement }),
-        }
-    }
 }

src/lib.rs

@@ -129,6 +129,23 @@ impl<K> Deref for Cas<K> {
     }
 }
 
+impl<K> Cas<K> {
+    /// Returns how many space the database occupies on disk.
+    /// # NOTE:
+    /// It does not include the size of dir in cas
+    /// So it can be around 256 * 256(l1) * 256(l2) bytes depending on the number of directories
+    /// created and fs used.
+    #[must_use]
+    pub fn stats(&self) -> DbStats {
+        self.0.stats()
+    }
+
+    #[must_use]
+    pub fn as_arc(&self) -> &Arc<CasInner<K>> {
+        &self.0
+    }
+}
+
 impl<K> Cas<K>
 where
     K: KeyBytes + Clone + Eq + Ord + std::hash::Hash + Debug + Send + Sync + 'static,
@@ -193,21 +210,6 @@ where
 
         Ok((cas, orphan_stats))
     }
-
-    /// Returns how many space the database occupies on disk.
-    /// # NOTE:
-    /// It does not include the size of dir in cas
-    /// So it can be around 256 * 256(l1) * 256(l2) bytes depending on the number of directories
-    /// created and fs used.
-    #[must_use]
-    pub fn stats(&self) -> DbStats {
-        self.0.stats()
-    }
-
-    #[must_use]
-    pub fn as_arc(&self) -> &Arc<CasInner<K>> {
-        &self.0
-    }
 }
 
 pub struct CasInner<K> {
@@ -316,17 +318,6 @@ where
         Ok(Self { _lockfile: lockfile, paths, index, datasync_channel, cas_manager })
     }
 
-    /// Returns a read-only view of the index state.
-    /// The returned guard holds a shared read lock until dropped.
-    pub fn read_index_state(&self) -> IndexReadGuard<'_, K> {
-        self.index.read_state()
-    }
-
-    #[must_use]
-    pub fn stats(&self) -> DbStats {
-        self.index.read_state().stats()
-    }
-
     /// Start a new transaction for the given key.
     pub fn put(&self, key: K) -> Result<Transaction<'_, K>, LibError> {
         Transaction::new(self, key).map_err(|e| match e {
@@ -442,11 +433,6 @@ where
         self.index.checkpoint(CheckpointReason::Explicit).map_err(LibError::Index)
     }
 
-    /// Returns root path of db provided at initialization
-    pub fn root_path(&self) -> &Path {
-        self.paths.db_root_path()
-    }
-
     fn with_blob_item<T, F>(&self, key: &K, f: F) -> Result<Option<T>, LibError>
     where
         F: FnOnce(&IndexStateItem) -> Result<T, CasManagerError>,
@@ -471,6 +457,24 @@ where
             }
         }
     }
+}
+
+impl<K> CasInner<K> {
+    /// Returns a read-only view of the index state.
+    /// The returned guard holds a shared read lock until dropped.
+    pub fn read_index_state(&self) -> IndexReadGuard<'_, K> {
+        self.index.read_state()
+    }
+
+    /// Returns root path of db provided at initialization
+    pub fn root_path(&self) -> &Path {
+        self.paths.db_root_path()
+    }
+
+    #[must_use]
+    pub fn stats(&self) -> DbStats {
+        self.index.read_state().stats()
+    }
 
     fn fdatasync(&self, file: File) -> Result<(), LibError> {
         match &self.datasync_channel {

src/orphan.rs

@@ -65,10 +65,7 @@ pub struct RecoveryResult {
     pub errors: Vec<String>,
 }
 
-impl<K> OrphanStats<K>
-where
-    K: KeyBytes + Clone + Eq + Ord + Hash + Debug + Send + Sync + 'static,
-{
+impl<K> OrphanStats<K> {
     /// Delete orphaned blobs
     pub fn delete_orphans(&self) -> Result<RecoveryResult, LibError> {
         let mut result = RecoveryResult::default();

src/transaction.rs

@@ -39,10 +39,7 @@ where
 }
 
 #[must_use = "Transaction must be completed by calling finish()"]
-pub struct Transaction<'a, K>
-where
-    K: Debug,
-{
+pub struct Transaction<'a, K> {
     pub(crate) temp_file: NamedTempFile,
     pub(crate) cas_inner: &'a CasInner<K>,
     pub(crate) writer: BufWriter<File>,
@@ -87,19 +84,6 @@ where
         })
     }
 
-    /// Append `data` to the transaction.
-    /// Most common usage is to incrementally compress and write chunks.
-    pub fn write(&mut self, data: &[u8]) -> Result<(), TransactionError> {
-        self.size += data.len() as u64;
-        self.hasher.update(data);
-        self.writer.write_all(data).map_err(|e| TransactionError::StagingFileIo {
-            operation: StagingFileOp::Write,
-            path: self.temp_file.path().to_path_buf(),
-            source: e,
-        })?;
-        Ok(())
-    }
-
     pub fn finish(self) -> Result<(), crate::LibError> {
         tracing::debug!("Finishing transaction for key '{:?}'", self.key);
         self.commit()
@@ -142,3 +126,18 @@ where
         Ok(())
     }
 }
+
+impl<'a, K> Transaction<'a, K> {
+    /// Append `data` to the transaction.
+    /// Most common usage is to incrementally compress and write chunks.
+    pub fn write(&mut self, data: &[u8]) -> Result<(), TransactionError> {
+        self.size += data.len() as u64;
+        self.hasher.update(data);
+        self.writer.write_all(data).map_err(|e| TransactionError::StagingFileIo {
+            operation: StagingFileOp::Write,
+            path: self.temp_file.path().to_path_buf(),
+            source: e,
+        })?;
+        Ok(())
+    }
+}