feat: add is_canonical to block_info() RPC result

Adds is_canonical field to the BlockInfo struct which is returned by
block_info() RPC.

perf: This requires a new call to
ArchivalState::block_belongs_to_canonical_chain() which may have to
search the path from block-digest to tip-digest.

So it potentially slows down block_info() RPC some.  However, this
enables the block-explorer the display the required info without a
2nd RPC call (per page request), so overall it should be a performance
win.

src/models/blockchain/block/block_info.rs

@@ -28,6 +28,7 @@ pub struct BlockInfo {
     pub fee: NeptuneCoins,
     pub is_genesis: bool,
     pub is_tip: bool,
+    pub is_canonical: bool,
 }
 
 // note: this is used by neptune-cli block-info command.
@@ -48,7 +49,8 @@ impl std::fmt::Display for BlockInfo {
             + &format!("mining_reward: {}\n", self.mining_reward)
             + &format!("fee: {}\n", self.fee)
             + &format!("is_genesis: {}\n", self.is_genesis)
-            + &format!("is_tip: {}\n", self.is_tip);
+            + &format!("is_tip: {}\n", self.is_tip)
+            + &format!("is_canonical: {}\n", self.is_canonical);
 
         write!(f, "{}", buf)
     }
@@ -59,6 +61,7 @@ impl BlockInfo {
         block: &Block,
         genesis_digest: Digest,
         tip_digest: Digest,
+        is_canonical: bool,
     ) -> Self {
         let body = block.body();
         let header = block.header();
@@ -76,6 +79,7 @@ impl BlockInfo {
             mining_reward: crate::Block::block_subsidy(header.height),
             is_genesis: digest == genesis_digest,
             is_tip: digest == tip_digest,
+            is_canonical,
         }
     }
 }

src/models/blockchain/block/block_selector.rs

@@ -102,9 +102,10 @@ impl FromStr for BlockSelector {
 }
 
 impl BlockSelector {
-    /// returns Digest for this selector, if it exists. Returns the digest of
-    /// the block belonging to the canonical chain if multiple blocks with
-    /// same height is found.
+    /// returns canonical chain block Digest for this selector, if it exists.
+    ///
+    /// note: if multiple blocks with same height are found only the digest
+    /// of the block belonging to canonical chain is returned.
     pub async fn as_digest(&self, state: &GlobalState) -> Option<Digest> {
         match self {
             BlockSelector::Digest(d) => Some(*d),

src/rpc_server.rs

@@ -821,13 +821,19 @@ impl RPC for NeptuneRPCServer {
 
         let state = self.state.lock_guard().await;
         let digest = block_selector.as_digest(&state).await?;
+        let tip_digest = state.chain.light_state().hash();
         let archival_state = state.chain.archival_state();
 
         let block = archival_state.get_block(digest).await.unwrap()?;
+        let is_canonical = archival_state
+            .block_belongs_to_canonical_chain(digest, tip_digest)
+            .await;
+
         Some(BlockInfo::from_block_and_digests(
             &block,
             archival_state.genesis_block().hash(),
-            state.chain.light_state().hash(),
+            tip_digest,
+            is_canonical,
         ))
     }
 
@@ -2117,12 +2123,22 @@ mod rpc_server_tests {
             global_state.chain.archival_state().genesis_block(),
             genesis_hash,
             tip_hash,
+            global_state
+                .chain
+                .archival_state()
+                .block_belongs_to_canonical_chain(genesis_hash, tip_hash)
+                .await,
         );
 
         let tip_block_info = BlockInfo::from_block_and_digests(
             global_state.chain.light_state(),
             genesis_hash,
             tip_hash,
+            global_state
+                .chain
+                .archival_state()
+                .block_belongs_to_canonical_chain(tip_hash, tip_hash)
+                .await,
         );
 
         // should find genesis block by Genesis selector