From d4bdff08f7de754461d9364302b7e8371e3d234e Mon Sep 17 00:00:00 2001
From: =?utf8?q?=E5=BF=97=E5=AE=87?= <hello@evanlinjin.me>
Date: Fri, 9 Jan 2026 17:09:03 +0800
Subject: [PATCH] feat(core): Add `prev_blockhash` method to `ToBlockHash`
 trait

---
 crates/core/src/checkpoint.rs | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/crates/core/src/checkpoint.rs b/crates/core/src/checkpoint.rs
index 0a394122..edb420dc 100644
--- a/crates/core/src/checkpoint.rs
+++ b/crates/core/src/checkpoint.rs
@@ -65,6 +65,11 @@ impl<D> Drop for CPInner<D> {
 pub trait ToBlockHash {
     /// Returns the [`BlockHash`] for the associated [`CheckPoint`] `data` type.
     fn to_blockhash(&self) -> BlockHash;
+
+    /// Returns `None` if the type has no knowledge of the previous [`BlockHash`].
+    fn prev_blockhash(&self) -> Option<BlockHash> {
+        None
+    }
 }
 
 impl ToBlockHash for BlockHash {
@@ -77,6 +82,10 @@ impl ToBlockHash for Header {
     fn to_blockhash(&self) -> BlockHash {
         self.block_hash()
     }
+
+    fn prev_blockhash(&self) -> Option<BlockHash> {
+        Some(self.prev_blockhash)
+    }
 }
 
 /// Trait that extracts a block time from [`CheckPoint`] `data`.
-- 
2.49.0