feat(driver): wait for engine (#851)

crates/driver/src/core.rs

@@ -54,6 +54,11 @@ where
         }
     }
 
+    /// Waits until the executor is ready.
+    pub async fn wait_for_executor(&mut self) {
+        self.executor.wait_until_ready().await;
+    }
+
     /// Advances the derivation pipeline to the target block number.
     ///
     /// ## Takes

crates/driver/src/executor.rs

@@ -1,5 +1,6 @@
 //! An abstraction for the driver's block executor.
 
+use alloc::boxed::Box;
 use core::{
     error::Error,
     fmt::{Debug, Display},
@@ -19,6 +20,9 @@ pub trait Executor {
     /// The error type for the Executor.
     type Error: Error + Debug + Display + ToString;
 
+    /// Waits for the executor to be ready.
+    async fn wait_until_ready(&mut self);
+
     /// Updates the safe header.
     fn update_safe_head(&mut self, header: Sealed<Header>);
 

crates/proof-sdk/proof/src/executor.rs

@@ -1,8 +1,9 @@
 //! An executor constructor.
 
-use alloc::sync::Arc;
+use alloc::{boxed::Box, sync::Arc};
 use alloy_consensus::{Header, Sealed};
 use alloy_primitives::B256;
+use async_trait::async_trait;
 use kona_driver::Executor;
 use kona_executor::{KonaHandleRegister, StatelessL2BlockExecutor, TrieDBProvider};
 use kona_mpt::TrieHinter;
@@ -45,13 +46,20 @@ where
     }
 }
 
+#[async_trait]
 impl<P, H> Executor for KonaExecutor<'_, P, H>
 where
     P: TrieDBProvider + Send + Sync + Clone,
     H: TrieHinter + Send + Sync + Clone,
 {
     type Error = kona_executor::ExecutorError;
 
+    /// Waits for the executor to be ready.
+    async fn wait_until_ready(&mut self) {
+        /* no-op for the kona executor */
+        /* This is used when an engine api is used instead of a stateless block executor */
+    }
+
     /// Updates the safe header.
     ///
     /// Since the L2 block executor is stateless, on an update to the safe head,