From 3c77dd9e2faa76fa192462b59042dee9a84a6c45 Mon Sep 17 00:00:00 2001
From: Matthias Seitz <matthias.seitz@outlook.de>
Date: Wed, 22 Feb 2023 23:59:19 +0100
Subject: [PATCH] feat(rpc): initial work in eth_call+estimate (#1514)

---
 Cargo.lock                         |  2 +
 crates/rpc/rpc/Cargo.toml          |  4 ++
 crates/rpc/rpc/src/eth/api/call.rs | 64 ++++++++++++++++++++++++++++++
 crates/rpc/rpc/src/eth/api/mod.rs  | 11 +++++
 4 files changed, 81 insertions(+)
 create mode 100644 crates/rpc/rpc/src/eth/api/call.rs

diff --git a/Cargo.lock b/Cargo.lock
index 3b72b16fbd..e0a6b59d4b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4903,6 +4903,7 @@ dependencies = [
  "jsonwebtoken",
  "pin-project",
  "rand 0.8.5",
+ "reth-executor",
  "reth-interfaces",
  "reth-network-api",
  "reth-primitives",
@@ -4913,6 +4914,7 @@ dependencies = [
  "reth-rpc-types",
  "reth-tasks",
  "reth-transaction-pool",
+ "revm",
  "secp256k1 0.26.0",
  "serde",
  "serde_json",
diff --git a/crates/rpc/rpc/Cargo.toml b/crates/rpc/rpc/Cargo.toml
index 4719d79aeb..35897baacf 100644
--- a/crates/rpc/rpc/Cargo.toml
+++ b/crates/rpc/rpc/Cargo.toml
@@ -19,8 +19,12 @@ reth-provider = { path = "../../storage/provider", features = ["test-utils"] }
 reth-transaction-pool = { path = "../../transaction-pool", features = ["test-utils"]}
 reth-network-api = { path = "../../net/network-api", features = ["test-utils"] }
 reth-rpc-engine-api = { path = "../rpc-engine-api" }
+reth-executor = { path = "../../executor" }
 reth-tasks = { path = "../../tasks" }
 
+# eth
+revm = "3.0.0"
+
 # rpc
 jsonrpsee = { version = "0.16" }
 http = "0.2.8"
diff --git a/crates/rpc/rpc/src/eth/api/call.rs b/crates/rpc/rpc/src/eth/api/call.rs
new file mode 100644
index 0000000000..fad0984e45
--- /dev/null
+++ b/crates/rpc/rpc/src/eth/api/call.rs
@@ -0,0 +1,64 @@
+//! Contains RPC handler implementations specific to endpoints that call/execute within evm.
+
+#![allow(unused)] // TODO rm later
+
+use crate::{eth::error::EthResult, EthApi};
+use reth_executor::revm_wrap::{State, SubState};
+use reth_primitives::{BlockId, U256};
+use reth_provider::{BlockProvider, StateProvider, StateProviderFactory};
+use reth_rpc_types::CallRequest;
+use revm::primitives::{BlockEnv, Env, ResultAndState};
+
+impl<Client, Pool, Network> EthApi<Client, Pool, Network>
+where
+    Client: BlockProvider + StateProviderFactory + 'static,
+{
+    /// Creates the [Env] used by the [EVM](revm::EVM) when executing a call.
+    fn build_call_env(&self, request: CallRequest, block_env: BlockEnv) -> Env {
+        todo!()
+    }
+
+    /// Executes the call request against the given `state` without committing any changes to the
+    /// database
+    pub(crate) fn call_with<S>(
+        &self,
+        request: CallRequest,
+        state: S,
+        block_env: BlockEnv,
+        // TODO add overrides
+    ) -> EthResult<ResultAndState>
+    where
+        S: StateProvider,
+    {
+        // the revm database impl
+        let mut db = SubState::new(State::new(state));
+        let mut evm = revm::EVM::new();
+        evm.env = self.build_call_env(request, block_env);
+        evm.database(db);
+        // TODO error conversion from EMVError to EthApiErr
+        let res = evm.transact_ref().unwrap();
+        Ok(res)
+    }
+
+    /// Estimate gas needed for execution of the `request` at the [BlockId] .
+    pub(crate) fn estimate_gas_at(&self, mut request: CallRequest, at: BlockId) -> EthResult<U256> {
+        // TODO get a StateProvider for the given blockId and BlockEnv
+        todo!()
+    }
+
+    /// Estimates the gas usage of the `request` with the state.
+    fn estimate_gas_with<S>(
+        &self,
+        mut request: CallRequest,
+        state: S,
+        block_env: BlockEnv,
+    ) -> EthResult<U256>
+    where
+        S: StateProvider,
+    {
+        // TODO: check if transfer
+        // binary search over range to find best gas
+
+        todo!()
+    }
+}
diff --git a/crates/rpc/rpc/src/eth/api/mod.rs b/crates/rpc/rpc/src/eth/api/mod.rs
index 176d40ce3e..4d635cf682 100644
--- a/crates/rpc/rpc/src/eth/api/mod.rs
+++ b/crates/rpc/rpc/src/eth/api/mod.rs
@@ -13,11 +13,14 @@ use reth_primitives::{
 use reth_provider::{BlockProvider, StateProviderFactory};
 use std::num::NonZeroUsize;
 
+use crate::eth::error::EthResult;
+use reth_provider::providers::ChainState;
 use reth_rpc_types::FeeHistoryCache;
 use reth_transaction_pool::TransactionPool;
 use std::sync::Arc;
 
 mod block;
+mod call;
 mod server;
 mod state;
 mod transactions;
@@ -100,6 +103,14 @@ where
         self.client().convert_block_number(num)
     }
 
+    /// Helper function to execute a closure with the database at a specific block.
+    pub(crate) fn with_state_at<F, T>(&self, _at: BlockId, _f: F) -> EthResult<T>
+    where
+        F: FnOnce(ChainState<'_>) -> T,
+    {
+        unimplemented!()
+    }
+
     /// Returns the state at the given [BlockId] enum or the latest.
     pub(crate) fn state_at_block_id_or_latest(
         &self,