From 9e25662deec2917dfae7e863fbc306935c05936c Mon Sep 17 00:00:00 2001
From: Brooks Prumo <brooks@solana.com>
Date: Sun, 3 Oct 2021 10:35:32 -0500
Subject: [PATCH] Add get_incremental_snapshot_hash_for_node() to gossip

Fixes #20377
---
 gossip/src/cluster_info.rs | 16 ++++++++++++++--
 gossip/src/crds_entry.rs   | 16 +++++++++++++++-
 2 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/gossip/src/cluster_info.rs b/gossip/src/cluster_info.rs
index 77aaf524bbf5fc..ac1ed7e52465f6 100644
--- a/gossip/src/cluster_info.rs
+++ b/gossip/src/cluster_info.rs
@@ -23,8 +23,8 @@ use {
         crds_gossip_error::CrdsGossipError,
         crds_gossip_pull::{CrdsFilter, ProcessPullStats, CRDS_GOSSIP_PULL_CRDS_TIMEOUT_MS},
         crds_value::{
-            self, CrdsData, CrdsValue, CrdsValueLabel, EpochSlotsIndex, LowestSlot, NodeInstance,
-            SnapshotHash, Version, Vote, MAX_WALLCLOCK,
+            self, CrdsData, CrdsValue, CrdsValueLabel, EpochSlotsIndex, IncrementalSnapshotHash,
+            LowestSlot, NodeInstance, SnapshotHash, Version, Vote, MAX_WALLCLOCK,
         },
         epoch_slots::EpochSlots,
         gossip_error::GossipError,
@@ -1115,6 +1115,18 @@ impl ClusterInfo {
         Some(map(hashes))
     }
 
+    pub fn get_incremental_snapshot_hash_for_node<F, Y>(&self, pubkey: &Pubkey, map: F) -> Option<Y>
+    where
+        F: FnOnce((Slot, &Vec<(Slot, Hash)>)) -> Y,
+    {
+        let gossip_crds = self.gossip.crds.read().unwrap();
+        let incremental_snapshot_hash = gossip_crds.get::<&IncrementalSnapshotHash>(*pubkey)?;
+        Some(map((
+            incremental_snapshot_hash.base_slot,
+            &incremental_snapshot_hash.hashes,
+        )))
+    }
+
     /// Returns epoch-slots inserted since the given cursor.
     /// Excludes entries from nodes with unkown or different shred version.
     pub fn get_epoch_slots(&self, cursor: &mut Cursor) -> Vec<EpochSlots> {
diff --git a/gossip/src/crds_entry.rs b/gossip/src/crds_entry.rs
index 3492af2966d1f4..051e59c9db04d5 100644
--- a/gossip/src/crds_entry.rs
+++ b/gossip/src/crds_entry.rs
@@ -3,7 +3,8 @@ use {
         contact_info::ContactInfo,
         crds::VersionedCrdsValue,
         crds_value::{
-            CrdsData, CrdsValue, CrdsValueLabel, LegacyVersion, LowestSlot, SnapshotHash, Version,
+            CrdsData, CrdsValue, CrdsValueLabel, IncrementalSnapshotHash, LegacyVersion,
+            LowestSlot, SnapshotHash, Version,
         },
     },
     indexmap::IndexMap,
@@ -68,6 +69,19 @@ impl<'a, 'b> CrdsEntry<'a, 'b> for &'a SnapshotHash {
     }
 }
 
+impl<'a, 'b> CrdsEntry<'a, 'b> for &'a IncrementalSnapshotHash {
+    type Key = Pubkey;
+    fn get_entry(table: &'a CrdsTable, key: Self::Key) -> Option<Self> {
+        let key = CrdsValueLabel::IncrementalSnapshotHashes(key);
+        match &table.get(&key)?.value.data {
+            CrdsData::IncrementalSnapshotHashes(incremental_snapshot_hash) => {
+                Some(incremental_snapshot_hash)
+            }
+            _ => None,
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use {