refactor: move epoch_exists to EpochManagerAdapter

Just to show how it works! Expect this repeated a bunch of times soon!

chain/chain/src/test_utils.rs

@@ -407,7 +407,11 @@ impl KeyValueRuntime {
     }
 }
 
-impl EpochManagerAdapter for KeyValueRuntime {}
+impl EpochManagerAdapter for KeyValueRuntime {
+    fn epoch_exists(&self, epoch_id: &EpochId) -> bool {
+        self.hash_to_valset.write().unwrap().contains_key(epoch_id)
+    }
+}
 
 impl RuntimeAdapter for KeyValueRuntime {
     fn genesis_state(&self) -> (Store, Vec<StateRoot>) {
@@ -1159,10 +1163,6 @@ impl RuntimeAdapter for KeyValueRuntime {
         }
     }
 
-    fn epoch_exists(&self, epoch_id: &EpochId) -> bool {
-        self.hash_to_valset.write().unwrap().contains_key(epoch_id)
-    }
-
     fn get_epoch_minted_amount(&self, _epoch_id: &EpochId) -> Result<Balance, Error> {
         Ok(0)
     }

chain/chain/src/types.rs

@@ -550,9 +550,6 @@ pub trait RuntimeAdapter: EpochManagerAdapter + Send + Sync {
     /// Get the block height for which garbage collection should not go over
     fn get_gc_stop_height(&self, block_hash: &CryptoHash) -> BlockHeight;
 
-    /// Check if epoch exists.
-    fn epoch_exists(&self, epoch_id: &EpochId) -> bool;
-
     /// Amount of tokens minted in given epoch.
     fn get_epoch_minted_amount(&self, epoch_id: &EpochId) -> Result<Balance, Error>;
 

chain/epoch-manager/src/adapter.rs

@@ -1,3 +1,5 @@
+use near_primitives::types::EpochId;
+
 use crate::{EpochManager, EpochManagerHandle};
 use std::sync::{RwLockReadGuard, RwLockWriteGuard};
 
@@ -8,7 +10,10 @@ use std::sync::{RwLockReadGuard, RwLockWriteGuard};
 /// we move it to a new trait. The end goal is for the code to use the concrete
 /// epoch manager type directly. Though, we might want to still keep this trait
 /// in, to allow for easy overriding of epoch manager in tests.
-pub trait EpochManagerAdapter: Send + Sync {}
+pub trait EpochManagerAdapter: Send + Sync {
+    /// Check if epoch exists.
+    fn epoch_exists(&self, epoch_id: &EpochId) -> bool;
+}
 
 /// A technical plumbing trait to conveniently implement [`EpochManagerAdapter`]
 /// for `NightshadeRuntime` without too much copy-paste.
@@ -30,4 +35,9 @@ impl HasEpochMangerHandle for EpochManagerHandle {
     }
 }
 
-impl<T: HasEpochMangerHandle + Send + Sync> EpochManagerAdapter for T {}
+impl<T: HasEpochMangerHandle + Send + Sync> EpochManagerAdapter for T {
+    fn epoch_exists(&self, epoch_id: &EpochId) -> bool {
+        let epoch_manager = self.read();
+        epoch_manager.get_epoch_info(epoch_id).is_ok()
+    }
+}

nearcore/src/runtime/mod.rs

@@ -1231,11 +1231,6 @@ impl RuntimeAdapter for NightshadeRuntime {
         .unwrap_or(self.genesis_config.genesis_height)
     }
 
-    fn epoch_exists(&self, epoch_id: &EpochId) -> bool {
-        let epoch_manager = self.epoch_manager.read();
-        epoch_manager.get_epoch_info(epoch_id).is_ok()
-    }
-
     fn get_epoch_minted_amount(&self, epoch_id: &EpochId) -> Result<Balance, Error> {
         let epoch_manager = self.epoch_manager.read();
         Ok(epoch_manager.get_epoch_info(epoch_id)?.minted_amount())