From 85d35f9733bcfd68cc94eae9abc3307158a6b007 Mon Sep 17 00:00:00 2001
From: silverpill <silverpill@firemail.cc>
Date: Sat, 16 Jul 2022 22:44:15 +0000
Subject: [PATCH] Wait for required number of confirmations before processing
 block

---
 src/ethereum/nft.rs           |  5 ++---
 src/ethereum/subscriptions.rs |  5 ++---
 src/ethereum/sync.rs          | 24 +++++++++++++++++-------
 3 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/src/ethereum/nft.rs b/src/ethereum/nft.rs
index 0eb1469..6184826 100644
--- a/src/ethereum/nft.rs
+++ b/src/ethereum/nft.rs
@@ -64,10 +64,9 @@ pub async fn process_nft_events(
 
     // Search for Transfer events
     let event_abi = contract.abi().event("Transfer")?;
-    let (from_block, to_block) = sync_state.get_scan_range(&contract.address());
-    let to_block = std::cmp::min(
+    let (from_block, to_block) = sync_state.get_scan_range(
+        &contract.address(),
         web3.eth().block_number().await?.as_u64(),
-        to_block,
     );
     let filter = FilterBuilder::default()
         .address(vec![contract.address()])
diff --git a/src/ethereum/subscriptions.rs b/src/ethereum/subscriptions.rs
index f9170b8..92d4632 100644
--- a/src/ethereum/subscriptions.rs
+++ b/src/ethereum/subscriptions.rs
@@ -69,10 +69,9 @@ pub async fn check_subscriptions(
 ) -> Result<(), EthereumError> {
     let db_client = &mut **get_database_client(db_pool).await?;
     let event_abi = contract.abi().event("UpdateSubscription")?;
-    let (from_block, to_block) = sync_state.get_scan_range(&contract.address());
-    let to_block = std::cmp::min(
+    let (from_block, to_block) = sync_state.get_scan_range(
+        &contract.address(),
         web3.eth().block_number().await?.as_u64(),
-        to_block,
     );
     let filter = FilterBuilder::default()
         .address(vec![contract.address()])
diff --git a/src/ethereum/sync.rs b/src/ethereum/sync.rs
index 14cd181..6e97e26 100644
--- a/src/ethereum/sync.rs
+++ b/src/ethereum/sync.rs
@@ -82,11 +82,21 @@ impl SyncState {
         }
     }
 
-    pub fn get_scan_range(&self, contract_address: &Address) -> (u64, u64) {
+    pub fn get_scan_range(
+        &self,
+        contract_address: &Address,
+        latest_block: u64,
+    ) -> (u64, u64) {
         let current_block = self.contracts[contract_address];
         // Take reorgs into account
-        let safe_current_block = current_block.saturating_sub(self.reorg_max_depth);
-        (safe_current_block, safe_current_block + self.sync_step)
+        let latest_safe_block = latest_block.saturating_sub(self.reorg_max_depth);
+        let next_block = std::cmp::min(
+            current_block + self.sync_step,
+            latest_safe_block,
+        );
+        // Next block should not be less than current block
+        let next_block = std::cmp::max(current_block, next_block);
+        (current_block, next_block)
     }
 
     pub fn is_out_of_sync(&self, contract_address: &Address) -> bool {
@@ -129,7 +139,7 @@ mod tests {
             10,
             Path::new("test"),
         );
-        let (from_block, to_block) = sync_state.get_scan_range(&address);
+        let (from_block, to_block) = sync_state.get_scan_range(&address, 555);
         assert_eq!(from_block, 0);
         assert_eq!(to_block, 100);
     }
@@ -144,8 +154,8 @@ mod tests {
             10,
             Path::new("test"),
         );
-        let (from_block, to_block) = sync_state.get_scan_range(&address);
-        assert_eq!(from_block, 490);
-        assert_eq!(to_block, 590);
+        let (from_block, to_block) = sync_state.get_scan_range(&address, 555);
+        assert_eq!(from_block, 500);
+        assert_eq!(to_block, 545);
     }
 }