feat: add ChainEventSubscriptions trait (#1338)

crates/interfaces/src/events.rs

@@ -0,0 +1,21 @@
+use reth_primitives::{Header, H256};
+use std::sync::Arc;
+use tokio::sync::mpsc::UnboundedReceiver;
+
+/// Type alias for a receiver that receives [NewBlockNotification]
+pub type NewBlockNotifications = UnboundedReceiver<NewBlockNotification>;
+
+/// A type that allows to register chain related event subscriptions.
+pub trait ChainEventSubscriptions {
+    /// Get notified when a new block was imported.
+    fn subscribe_new_blocks(&self) -> NewBlockNotifications;
+}
+
+/// A notification that's emitted when a new block was imported.
+#[derive(Clone, Debug)]
+pub struct NewBlockNotification {
+    /// Hash of the block that was imported
+    pub hash: H256,
+    /// The block header of the new block
+    pub header: Arc<Header>,
+}

crates/interfaces/src/lib.rs

@@ -7,29 +7,31 @@
 
 //! Reth interface bindings
 
-/// Block Execution traits.
-pub mod executor;
-
 /// Consensus traits.
 pub mod consensus;
 
-/// Provider error
-pub mod provider;
-
 /// Database error
 pub mod db;
 
+/// Block Execution traits.
+pub mod executor;
+
+/// Possible errors when interacting with the chain.
+mod error;
+pub use error::{Error, Result};
+
+/// Traits for subscribing to events.
+pub mod events;
+
 /// P2P traits.
 pub mod p2p;
 
+/// Provider error
+pub mod provider;
+
 /// Syncing related traits.
 pub mod sync;
 
-/// Possible errors when interacting with the chain.
-mod error;
-
-pub use error::{Error, Result};
-
 #[cfg(any(test, feature = "test-utils"))]
 /// Common test helpers for mocking out Consensus, Downloaders and Header Clients.
 pub mod test_utils;