Split the EVM (#126)

* wip: split evm

* docs: update DbConnect docs

Author: prestwich

Cargo.toml

@@ -45,7 +45,7 @@ alloy = { version = "1.0.25", default-features = false, features = [
 ] }
 
 revm = { version = "27.1", default-features = false }
-revm-inspectors = { version = "0.27.1", optional = true }
+revm-inspectors = { version = "0.27.3", optional = true }
 
 dashmap = { version = "6.1.0", optional = true }
 tracing = { version = "0.1.41", optional = true }
@@ -86,7 +86,7 @@ concurrent-db = ["dep:dashmap"]
 
 estimate_gas = ["optional_eip3607", "optional_no_base_fee", "dep:tracing"]
 
-test-utils = ["revm/std", "revm/serde-json", "revm/alloydb"]
+test-utils = ["revm/std", "revm/serde-json", "revm/alloydb", "alloy/signers", "alloy/signer-local"]
 
 secp256k1 = ["revm/secp256k1"]
 c-kzg = ["revm/c-kzg"]

src/db/mod.rs

@@ -4,7 +4,7 @@ pub mod sync;
 
 /// Database abstraction traits.
 mod traits;
-pub use traits::{ArcUpgradeError, CachingDb, StateAcc, TryCachingDb, TryStateAcc};
+pub use traits::{ArcUpgradeError, CachingDb, DbConnect, StateAcc, TryCachingDb, TryStateAcc};
 
 /// Cache-on-write database. A memory cache that caches only on write, not on
 /// read. Intended to wrap some other caching database.

src/db/traits.rs

@@ -5,6 +5,42 @@ use revm::{
 };
 use std::{collections::BTreeMap, convert::Infallible, sync::Arc};
 
+/// Trait for types that can be used to connect to a database.
+///
+/// Connectors should contain configuration information like filesystem paths.
+/// They are intended to enable parallel instantiation of multiple EVMs in
+/// multiple threads sharing some database configuration
+///
+/// `DbConnect` is blanket implemented for clonable [`Database`] types by
+/// simply cloning the database instance. This allows already-instantiated DBs
+/// to be used as connectors, however, if the [`Database`] uses a shared
+/// resource like a file or network connection, care should be taken to ensure
+/// that the implementation does not share uintended state between EVM
+/// instances.
+pub trait DbConnect: Sync {
+    /// The database type returned when connecting.
+    type Database: Database;
+
+    /// The error type returned when connecting to the database.
+    type Error: core::error::Error;
+
+    /// Connect to the database.
+    fn connect(&self) -> Result<Self::Database, Self::Error>;
+}
+
+impl<Db> DbConnect for Db
+where
+    Db: Database + Clone + Sync,
+{
+    type Database = Self;
+
+    type Error = Infallible;
+
+    fn connect(&self) -> Result<Self::Database, Self::Error> {
+        Ok(self.clone())
+    }
+}
+
 /// Abstraction trait covering types that accumulate state changes into a
 /// [`BundleState`]. The prime example of this is [`State`]. These types are
 /// use to accumulate state changes during the execution of a sequence of

src/driver/bundle.rs

@@ -1,4 +1,4 @@
-use crate::{helpers::Ctx, states::EvmBundleDriverErrored, EvmNeedsTx};
+use crate::{helpers::Ctx, EvmBundleDriverErrored, EvmNeedsTx};
 use revm::{
     context::result::EVMError, inspector::NoOpInspector, Database, DatabaseCommit, Inspector,
 };