From 367ea1a8378f829886ba2505b1163d05bd93d41f Mon Sep 17 00:00:00 2001
From: Boog900 <54e72d8a-345f-4599-bd90-c6b9bc7d0ec5@aleeas.com>
Date: Tue, 5 Sep 2023 19:49:01 +0100
Subject: [PATCH] add method to init the hard fork struct at a certain height.

---
 consensus/src/bin/scan_chain.rs |  5 ++---
 consensus/src/hardforks.rs      | 38 ++++++++++++++++++++++++++-------
 2 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/consensus/src/bin/scan_chain.rs b/consensus/src/bin/scan_chain.rs
index d8bfcdb..8d71db7 100644
--- a/consensus/src/bin/scan_chain.rs
+++ b/consensus/src/bin/scan_chain.rs
@@ -7,14 +7,13 @@ use std::pin::Pin;
 use std::task::{Context, Poll};
 use tower::balance::p2c::Balance;
 use tower::discover::Change;
-use tower::util::{BoxService};
+use tower::util::BoxService;
 
 use tracing::level_filters::LevelFilter;
 
 use monero_consensus::hardforks::{HardForkConfig, HardForks};
 use monero_consensus::rpc::Rpc;
 
-
 struct RpcDiscoverer(Vec<String>, u64);
 
 impl Stream for RpcDiscoverer {
@@ -80,7 +79,7 @@ async fn main() {
     let rpc_buffer = tower::buffer::Buffer::new(BoxService::new(rpc_balance), 3);
     let rpc = tower::retry::Retry::new(Attempts(3), rpc_buffer);
 
-    let _hfs = HardForks::init(HardForkConfig::default(), rpc.clone())
+    let _hfs = HardForks::init_at_chain_height(HardForkConfig::default(), 1009827, rpc.clone())
         .await
         .unwrap();
 }
diff --git a/consensus/src/hardforks.rs b/consensus/src/hardforks.rs
index 2873e4c..6d1abfb 100644
--- a/consensus/src/hardforks.rs
+++ b/consensus/src/hardforks.rs
@@ -230,6 +230,27 @@ impl HardForks {
              panic!("Database sent incorrect response")
          };
 
+        let mut hfs =
+            HardForks::init_at_chain_height(config, chain_height, database.clone()).await?;
+
+        // This is only needed if the database moves independently of the HardFork class aka if we are checking a node instead of keeping state ourself.
+        hfs.resync(&mut database).await?;
+
+        hfs.check_set_new_hf();
+
+        tracing::info!("HardFork state: {:?}", hfs);
+
+        Ok(hfs)
+    }
+
+    pub async fn init_at_chain_height<D: Database + Clone>(
+        config: HardForkConfig,
+        chain_height: u64,
+        mut database: D,
+    ) -> Result<Self, Error>
+    where
+        D::Future: Send + 'static,
+    {
         let block_heights = if chain_height > config.window {
             chain_height - config.window..chain_height
         } else {
@@ -257,8 +278,6 @@ impl HardForks {
             last_height: chain_height - 1,
         };
 
-        hfs.resync(&mut database).await?;
-
         hfs.check_set_new_hf();
 
         tracing::info!("HardFork state: {:?}", hfs);
@@ -285,7 +304,7 @@ impl HardForks {
         loop {
             while chain_height > self.last_height + 1 {
                 self.get_and_account_new_block(self.last_height + 1, &mut database)
-                    .await;
+                    .await?;
             }
 
             let DatabaseResponse::ChainHeight(c_h) = database
@@ -309,13 +328,16 @@ impl HardForks {
         }
     }
 
-    async fn get_and_account_new_block<D: Database>(&mut self, height: u64, mut database: D) {
-        let header = get_block_header(&mut database, height)
-            .await
-            .expect("Error retrieving block we should have in database");
+    async fn get_and_account_new_block<D: Database>(
+        &mut self,
+        height: u64,
+        mut database: D,
+    ) -> Result<(), Error> {
+        let header = get_block_header(&mut database, height).await?;
 
         self.new_block(HardFork::from_vote(&header.minor_version), height, database)
-            .await
+            .await;
+        Ok(())
     }
 
     pub fn check_block_version_vote(&self, version: &HardFork, vote: &HardFork) -> bool {