chore: Add helper functions for JournalInit #1879 (#1961)

* add journalinit type

* replace from into convention with explicit helpers

crates/context/src/journal_init.rs

@@ -0,0 +1,35 @@
+use super::journaled_state::JournaledState;
+use database_interface::EmptyDB;
+
+/// A clonable version of JournaledState that uses EmptyDB.
+pub type JournalInit = JournaledState<EmptyDB>;
+
+impl<DB> JournaledState<DB> {
+    pub fn into_init(self) -> JournalInit {
+        JournalInit {
+            database: EmptyDB::default(),
+            state: self.state,
+            transient_storage: self.transient_storage,
+            logs: self.logs,
+            depth: self.depth,
+            journal: self.journal,
+            spec: self.spec,
+            warm_preloaded_addresses: self.warm_preloaded_addresses,
+            precompiles: self.precompiles,
+        }
+    }
+
+    pub fn to_init(&self) -> JournalInit {
+        JournalInit {
+            database: EmptyDB::default(),
+            state: self.state.clone(),
+            transient_storage: self.transient_storage.clone(),
+            logs: self.logs.clone(),
+            depth: self.depth,
+            journal: self.journal.clone(),
+            spec: self.spec,
+            warm_preloaded_addresses: self.warm_preloaded_addresses.clone(),
+            precompiles: self.precompiles.clone(),
+        }
+    }
+}

crates/context/src/journaled_state.rs

@@ -13,6 +13,8 @@ use state::{Account, EvmState, EvmStorageSlot, TransientStorage};
 use core::mem;
 use std::{vec, vec::Vec};
 
+use crate::JournalInit;
+
 /// A journal of state changes internal to the EVM
 ///
 /// On each additional call, the depth of the journaled state is increased (`depth`) and a new journal is added.
@@ -1045,3 +1047,20 @@ pub enum JournalEntry {
     /// Revert: Revert to previous bytecode.
     CodeChange { address: Address },
 }
+
+impl<DB> JournaledState<DB> {
+    /// Initialize a new JournaledState from JournalInit with a database
+    pub fn from_init(init: &JournalInit, database: DB) -> Self {
+        Self {
+            database,
+            state: init.state.clone(),
+            transient_storage: init.transient_storage.clone(),
+            logs: init.logs.clone(),
+            depth: init.depth,
+            journal: init.journal.clone(),
+            spec: init.spec,
+            warm_preloaded_addresses: init.warm_preloaded_addresses.clone(),
+            precompiles: init.precompiles.clone(),
+        }
+    }
+}

crates/context/src/lib.rs

@@ -8,11 +8,13 @@ extern crate alloc as std;
 pub mod block;
 pub mod cfg;
 pub mod context;
+mod journal_init;
 pub mod journaled_state;
 pub mod tx;
 
 pub use block::BlockEnv;
 pub use cfg::{Cfg, CfgEnv};
 pub use context::*;
+pub use journal_init::JournalInit;
 pub use journaled_state::*;
 pub use tx::TxEnv;