chore: move traits for safe and finalized block read/write (#12786)

crates/storage/provider/src/traits/mod.rs

@@ -25,6 +25,3 @@ pub use full::{FullProvider, FullRpcProvider};
 
 mod tree_viewer;
 pub use tree_viewer::TreeViewer;
-
-mod finalized_block;
-pub use finalized_block::{ChainStateBlockReader, ChainStateBlockWriter};

crates/storage/storage-api/src/block.rs

@@ -267,3 +267,24 @@ pub trait BlockReaderIdExt: BlockReader + ReceiptProviderIdExt {
     /// Returns `None` if block is not found.
     fn ommers_by_id(&self, id: BlockId) -> ProviderResult<Option<Vec<Header>>>;
 }
+
+/// Functionality to read the last known chain blocks from the database.
+pub trait ChainStateBlockReader: Send + Sync {
+    /// Returns the last finalized block number.
+    ///
+    /// If no finalized block has been written yet, this returns `None`.
+    fn last_finalized_block_number(&self) -> ProviderResult<Option<BlockNumber>>;
+    /// Returns the last safe block number.
+    ///
+    /// If no safe block has been written yet, this returns `None`.
+    fn last_safe_block_number(&self) -> ProviderResult<Option<BlockNumber>>;
+}
+
+/// Functionality to write the last known chain blocks to the database.
+pub trait ChainStateBlockWriter: Send + Sync {
+    /// Saves the given finalized block number in the DB.
+    fn save_finalized_block_number(&self, block_number: BlockNumber) -> ProviderResult<()>;
+
+    /// Saves the given safe block number in the DB.
+    fn save_safe_block_number(&self, block_number: BlockNumber) -> ProviderResult<()>;
+}