feat: add helper EvmFactory type that modifies the PrecompilesMap

crates/evm/src/eth/mod.rs

@@ -281,6 +281,56 @@ impl EvmFactory for EthEvmFactory {
     }
 }
 
+/// Trait for modifying precompiles based on spec ID.
+pub trait PrecompileModifies<SpecId> {
+    /// Modifies the precompiles based on the spec ID.
+    fn modify(&self, precompiles: &mut PrecompilesMap, spec_id: SpecId);
+}
+
+/// A wrapper around an [`EvmFactory`] that modifies the precompiles based on the spec ID.
+#[derive(Debug, Clone, Copy)]
+pub struct EvmFactoryWith<Evm, PrecompilesInit> {
+    factory: Evm,
+    precompile_init: PrecompilesInit,
+}
+
+impl<F, P> EvmFactory for EvmFactoryWith<F, P>
+where
+    F: EvmFactory<Precompiles = PrecompilesMap, Spec = SpecId>,
+    P: PrecompileModifies<SpecId>,
+{
+    type Evm<DB: Database, I: Inspector<Self::Context<DB>>> = F::Evm<DB, I>;
+    type Context<DB: Database> = F::Context<DB>;
+    type Tx = F::Tx;
+    type Error<DBError: core::error::Error + Send + Sync + 'static> = F::Error<DBError>;
+    type HaltReason = F::HaltReason;
+    type Spec = F::Spec;
+    type Precompiles = F::Precompiles;
+
+    fn create_evm<DB: Database>(
+        &self,
+        db: DB,
+        input: EvmEnv<Self::Spec>,
+    ) -> Self::Evm<DB, NoOpInspector> {
+        let spec_id = input.cfg_env.spec;
+        let mut evm = self.factory.create_evm(db, input);
+        self.precompile_init.modify(evm.precompiles_mut(), spec_id);
+        evm
+    }
+
+    fn create_evm_with_inspector<DB: Database, I: Inspector<Self::Context<DB>>>(
+        &self,
+        db: DB,
+        input: EvmEnv<Self::Spec>,
+        inspector: I,
+    ) -> Self::Evm<DB, I> {
+        let spec_id = input.cfg_env.spec;
+        let mut evm = self.factory.create_evm_with_inspector(db, input, inspector);
+        self.precompile_init.modify(evm.precompiles_mut(), spec_id);
+        evm
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;