From 3e15172df259b59012483e41d5cc24e0b561b692 Mon Sep 17 00:00:00 2001
From: Guy Nir <guy.n@starkware.co>
Date: Sun, 26 Jan 2025 16:45:53 +0200
Subject: [PATCH] feat(starknet_l1_provider): add baselayer interface to query
 ethereum gas price

---
 .../src/ethereum_base_layer_contract.rs       | 76 ++++++++++++++++++-
 crates/papyrus_base_layer/src/lib.rs          | 26 +++++++
 2 files changed, 100 insertions(+), 2 deletions(-)

diff --git a/crates/papyrus_base_layer/src/ethereum_base_layer_contract.rs b/crates/papyrus_base_layer/src/ethereum_base_layer_contract.rs
index 0fa9e91d253..15fbcbacb4d 100644
--- a/crates/papyrus_base_layer/src/ethereum_base_layer_contract.rs
+++ b/crates/papyrus_base_layer/src/ethereum_base_layer_contract.rs
@@ -7,7 +7,12 @@ use alloy_json_rpc::RpcError;
 use alloy_primitives::Address as EthereumContractAddress;
 use alloy_provider::network::Ethereum;
 use alloy_provider::{Provider, ProviderBuilder, RootProvider};
-use alloy_rpc_types_eth::{BlockId, BlockTransactionsKind, Filter as EthEventFilter};
+use alloy_rpc_types_eth::{
+    BlockId,
+    BlockNumberOrTag,
+    BlockTransactionsKind,
+    Filter as EthEventFilter,
+};
 use alloy_sol_types::{sol, sol_data};
 use alloy_transport::TransportErrorKind;
 use alloy_transport_http::{Client, Http};
@@ -21,7 +26,7 @@ use starknet_api::StarknetApiError;
 use url::Url;
 use validator::Validate;
 
-use crate::{BaseLayerContract, L1BlockNumber, L1BlockReference, L1Event};
+use crate::{BaseLayerContract, L1BlockNumber, L1BlockReference, L1Event, PriceSample};
 
 pub type EthereumBaseLayerResult<T> = Result<T, EthereumBaseLayerError>;
 
@@ -131,6 +136,73 @@ impl BaseLayerContract for EthereumBaseLayerContract {
             hash: block.header.hash.0,
         }))
     }
+
+    async fn get_block_timestamp(&self, block_number: u64) -> EthereumBaseLayerResult<Option<u64>> {
+        let block = self
+            .contract
+            .provider()
+            .get_block(
+                BlockId::Number(BlockNumberOrTag::Number(block_number)),
+                BlockTransactionsKind::Hashes,
+            )
+            .await?;
+        Ok(block.map(|block| block.header.timestamp))
+    }
+
+    async fn get_block_gas_price(
+        &self,
+        block_number: u64,
+    ) -> EthereumBaseLayerResult<Option<u128>> {
+        let block = self
+            .contract
+            .provider()
+            .get_block(
+                BlockId::Number(BlockNumberOrTag::Number(block_number)),
+                BlockTransactionsKind::Hashes,
+            )
+            .await?;
+        Ok(block.and_then(|block| block.header.base_fee_per_gas))
+    }
+
+    async fn get_block_data_gas_price(
+        &self,
+        block_number: u64,
+    ) -> EthereumBaseLayerResult<Option<u128>> {
+        let block = self
+            .contract
+            .provider()
+            .get_block(
+                BlockId::Number(BlockNumberOrTag::Number(block_number)),
+                BlockTransactionsKind::Hashes,
+            )
+            .await?;
+        Ok(block.and_then(|block| block.header.blob_fee()))
+    }
+
+    // Combine the above three functions into one call, which is more efficient.
+    async fn get_price_sample(
+        &self,
+        block_number: u64,
+    ) -> EthereumBaseLayerResult<Option<PriceSample>> {
+        let block = self
+            .contract
+            .provider()
+            .get_block(
+                BlockId::Number(BlockNumberOrTag::Number(block_number)),
+                BlockTransactionsKind::Hashes,
+            )
+            .await?;
+        if let Some(block) = block {
+            match (block.header.timestamp, block.header.base_fee_per_gas, block.header.blob_fee()) {
+                (timestamp, Some(base_fee_per_gas), Some(blob_fee)) => {
+                    Ok(Some(PriceSample { timestamp, base_fee_per_gas, blob_fee }))
+                }
+                _ => Ok(None),
+            }
+        } else {
+            Ok(None)
+        }
+    }
 }
 
 #[derive(thiserror::Error, Debug)]
diff --git a/crates/papyrus_base_layer/src/lib.rs b/crates/papyrus_base_layer/src/lib.rs
index a3ac9e30702..3822b2156a1 100644
--- a/crates/papyrus_base_layer/src/lib.rs
+++ b/crates/papyrus_base_layer/src/lib.rs
@@ -60,6 +60,32 @@ pub trait BaseLayerContract {
         block_range: RangeInclusive<L1BlockNumber>,
         event_identifiers: &[&str],
     ) -> Result<Vec<L1Event>, Self::Error>;
+
+    async fn get_block_timestamp(&self, block_number: u64) -> Result<Option<u64>, Self::Error>;
+    async fn get_block_gas_price(&self, block_number: u64) -> Result<Option<u128>, Self::Error>;
+    async fn get_block_data_gas_price(
+        &self,
+        block_number: u64,
+    ) -> Result<Option<u128>, Self::Error>;
+    async fn get_price_sample(&self, block_number: u64)
+    -> Result<Option<PriceSample>, Self::Error>;
+}
+
+/// A struct the holds together the data on the baselayer's gas prices, for a given timestamp.
+pub struct PriceSample {
+    timestamp: u64,
+    base_fee_per_gas: u128,
+    blob_fee: u128,
+}
+
+impl Display for PriceSample {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "PriceSample {{ timestamp: {}, base_fee_per_gas: {}, blob_fee: {} }}",
+            self.timestamp, self.base_fee_per_gas, self.blob_fee
+        )
+    }
 }
 
 /// Reference to an L1 block, extend as needed.