From e09b3e098a0a1fe5a687b92102ac6b11a6e381ea Mon Sep 17 00:00:00 2001
From: Matthias Seitz <matthias.seitz@outlook.de>
Date: Thu, 2 Feb 2023 23:21:11 +0100
Subject: [PATCH] feat(rpc): add basic state access functions (#1136)

---
 crates/rpc/rpc/src/eth/api/block.rs | 19 ++++++++++
 crates/rpc/rpc/src/eth/api/mod.rs   | 59 ++++++++++++++++++++++++++++-
 crates/rpc/rpc/src/eth/api/state.rs | 20 ++++++++++
 3 files changed, 97 insertions(+), 1 deletion(-)
 create mode 100644 crates/rpc/rpc/src/eth/api/block.rs
 create mode 100644 crates/rpc/rpc/src/eth/api/state.rs

diff --git a/crates/rpc/rpc/src/eth/api/block.rs b/crates/rpc/rpc/src/eth/api/block.rs
new file mode 100644
index 000000000..47e121991
--- /dev/null
+++ b/crates/rpc/rpc/src/eth/api/block.rs
@@ -0,0 +1,19 @@
+//! Contains RPC handler implementations specific to blocks.
+
+use crate::{eth::error::EthResult, EthApi};
+use reth_primitives::H256;
+use reth_provider::{BlockProvider, StateProviderFactory};
+use reth_rpc_types::RichBlock;
+
+impl<Pool, Client, Network> EthApi<Pool, Client, Network>
+where
+    Client: BlockProvider + StateProviderFactory + 'static,
+{
+    pub(crate) async fn block_by_hash(
+        &self,
+        _hash: H256,
+        _full: bool,
+    ) -> EthResult<Option<RichBlock>> {
+        todo!()
+    }
+}
diff --git a/crates/rpc/rpc/src/eth/api/mod.rs b/crates/rpc/rpc/src/eth/api/mod.rs
index 2dd681e5c..da200b611 100644
--- a/crates/rpc/rpc/src/eth/api/mod.rs
+++ b/crates/rpc/rpc/src/eth/api/mod.rs
@@ -7,13 +7,18 @@ use crate::eth::signer::EthSigner;
 use async_trait::async_trait;
 use reth_interfaces::Result;
 use reth_network_api::NetworkInfo;
-use reth_primitives::{Address, ChainInfo, U64};
+use reth_primitives::{
+    rpc::{BlockId, BlockNumber},
+    Address, ChainInfo, H256, U64,
+};
 use reth_provider::{BlockProvider, StateProviderFactory};
 use reth_rpc_types::Transaction;
 use reth_transaction_pool::TransactionPool;
 use std::sync::Arc;
 
+mod block;
 mod server;
+mod state;
 mod transactions;
 
 /// `Eth` API trait.
@@ -72,6 +77,58 @@ impl<Pool, Client, Network> EthApi<Pool, Client, Network> {
     }
 }
 
+// === State access helpers ===
+
+impl<Pool, Client, Network> EthApi<Pool, Client, Network>
+where
+    Client: BlockProvider + StateProviderFactory + 'static,
+{
+    fn convert_block_number(&self, num: BlockNumber) -> Result<Option<u64>> {
+        self.client().convert_block_number(num)
+    }
+
+    /// Returns the state at the given [BlockId] enum.
+    pub(crate) fn state_at_block_id(
+        &self,
+        block_id: BlockId,
+    ) -> Result<Option<<Client as StateProviderFactory>::HistorySP<'_>>> {
+        match block_id {
+            BlockId::Hash(hash) => self.state_at_hash(H256(hash.0)).map(Some),
+            BlockId::Number(num) => self.state_at_block_number(num),
+        }
+    }
+
+    /// Returns the state at the given [BlockNumber] enum
+    ///
+    /// Returns `None` if no state available.
+    pub(crate) fn state_at_block_number(
+        &self,
+        num: BlockNumber,
+    ) -> Result<Option<<Client as StateProviderFactory>::HistorySP<'_>>> {
+        if let Some(number) = self.convert_block_number(num)? {
+            self.state_at_number(number).map(Some)
+        } else {
+            Ok(None)
+        }
+    }
+
+    /// Returns the state at the given block number
+    pub(crate) fn state_at_hash(
+        &self,
+        block_hash: H256,
+    ) -> Result<<Client as StateProviderFactory>::HistorySP<'_>> {
+        self.client().history_by_block_hash(block_hash)
+    }
+
+    /// Returns the state at the given block number
+    pub(crate) fn state_at_number(
+        &self,
+        block_number: u64,
+    ) -> Result<<Client as StateProviderFactory>::HistorySP<'_>> {
+        self.client().history_by_block_number(block_number)
+    }
+}
+
 #[async_trait]
 impl<Pool, Client, Network> EthApiSpec for EthApi<Pool, Client, Network>
 where
diff --git a/crates/rpc/rpc/src/eth/api/state.rs b/crates/rpc/rpc/src/eth/api/state.rs
new file mode 100644
index 000000000..9eb2d4bb1
--- /dev/null
+++ b/crates/rpc/rpc/src/eth/api/state.rs
@@ -0,0 +1,20 @@
+//! Contains RPC handler implementations specific to state.
+
+use crate::EthApi;
+use reth_interfaces::Result;
+use reth_primitives::{rpc::BlockId, Address, H256, U256};
+use reth_provider::{BlockProvider, StateProviderFactory};
+
+impl<Pool, Client, Network> EthApi<Pool, Client, Network>
+where
+    Client: BlockProvider + StateProviderFactory + 'static,
+{
+    async fn storage_at(
+        &self,
+        _address: Address,
+        _index: U256,
+        _block_number: Option<BlockId>,
+    ) -> Result<H256> {
+        todo!()
+    }
+}