From 9676584ffeb0f20336c7a91f12e395fa6e2e39fd Mon Sep 17 00:00:00 2001
From: Luke Parker <lukeparker5132@gmail.com>
Date: Sun, 16 Apr 2023 01:03:32 -0400
Subject: [PATCH] Resolve #245

---
 processor/src/coins/bitcoin.rs |  7 +++++++
 processor/src/coins/mod.rs     |  1 +
 processor/src/coins/monero.rs  |  4 ++++
 processor/src/scanner.rs       | 12 +++++++++++-
 4 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/processor/src/coins/bitcoin.rs b/processor/src/coins/bitcoin.rs
index 2940833e..e491c92f 100644
--- a/processor/src/coins/bitcoin.rs
+++ b/processor/src/coins/bitcoin.rs
@@ -197,6 +197,13 @@ impl BlockTrait<Bitcoin> for Block {
     hash.reverse();
     hash
   }
+
+  fn parent(&self) -> Self::Id {
+    let mut hash = *self.header.prev_blockhash.as_raw_hash().as_byte_array();
+    hash.reverse();
+    hash
+  }
+
   fn median_fee(&self) -> Fee {
     // TODO
     Fee(20)
diff --git a/processor/src/coins/mod.rs b/processor/src/coins/mod.rs
index f9ff6e43..1f4d212a 100644
--- a/processor/src/coins/mod.rs
+++ b/processor/src/coins/mod.rs
@@ -175,6 +175,7 @@ pub trait Block<C: Coin>: Send + Sync + Sized + Clone + Debug {
   // This is currently bounded to being 32-bytes.
   type Id: 'static + Id;
   fn id(&self) -> Self::Id;
+  fn parent(&self) -> Self::Id;
   fn median_fee(&self) -> C::Fee;
 }
 
diff --git a/processor/src/coins/monero.rs b/processor/src/coins/monero.rs
index 9f48fcb6..4d4b8531 100644
--- a/processor/src/coins/monero.rs
+++ b/processor/src/coins/monero.rs
@@ -142,6 +142,10 @@ impl BlockTrait<Monero> for Block {
     self.0
   }
 
+  fn parent(&self) -> Self::Id {
+    self.1.header.previous
+  }
+
   fn median_fee(&self) -> Fee {
     // TODO
     Fee { per_weight: 80000, mask: 10000 }
diff --git a/processor/src/scanner.rs b/processor/src/scanner.rs
index 1d766226..867e6cf2 100644
--- a/processor/src/scanner.rs
+++ b/processor/src/scanner.rs
@@ -395,12 +395,22 @@ impl<C: Coin, D: Db> Scanner<C, D> {
             let block_id = block.id();
 
             if let Some(id) = ScannerDb::<C, D>::block(&scanner.db.0, i) {
-              // TODO2: Also check this block builds off the previous block
               if id != block_id {
                 panic!("reorg'd from finalized {} to {}", hex::encode(id), hex::encode(block_id));
               }
             } else {
               info!("Found new block: {}", hex::encode(&block_id));
+
+              if let Some(id) = ScannerDb::<C, D>::block(&scanner.db.0, i.saturating_sub(1)) {
+                if id != block.parent() {
+                  panic!(
+                    "block {} doesn't build off expected parent {}",
+                    hex::encode(block_id),
+                    hex::encode(id),
+                  );
+                }
+              }
+
               let mut txn = scanner.db.0.txn();
               ScannerDb::<C, D>::save_block(&mut txn, i, &block_id);
               txn.commit();