From e30e4cc603a143dc82be6a2e2d808ea8227390bd Mon Sep 17 00:00:00 2001
From: Michael Vines <mvines@gmail.com>
Date: Fri, 1 Mar 2019 13:13:32 -0800
Subject: [PATCH] Remove get_confirmation_timestamp() from HashQueue

---
 runtime/src/bank.rs                | 26 +++++++++++++++++++++++---
 runtime/src/hash_queue.rs          | 26 +-------------------------
 src/leader_confirmation_service.rs | 14 +++-----------
 3 files changed, 27 insertions(+), 39 deletions(-)

diff --git a/runtime/src/bank.rs b/runtime/src/bank.rs
index 41462347b6..1e59e18b28 100644
--- a/runtime/src/bank.rs
+++ b/runtime/src/bank.rs
@@ -319,11 +319,31 @@ impl Bank {
     /// tick that has achieved confirmation
     pub fn get_confirmation_timestamp(
         &self,
-        ticks_and_stakes: &mut [(u64, u64)],
+        mut slots_and_stakes: Vec<(u64, u64)>,
         supermajority_stake: u64,
     ) -> Option<u64> {
-        let hash_queue = self.tick_hash_queue.read().unwrap();
-        hash_queue.get_confirmation_timestamp(ticks_and_stakes, supermajority_stake)
+        // Sort by slot height
+        slots_and_stakes.sort_by(|a, b| a.0.cmp(&b.0));
+
+        let max_slot = self.slot_height();
+        let min_slot =
+            max_slot.saturating_sub(MAX_RECENT_TICK_HASHES as u64 / self.ticks_per_slot());
+
+        let mut total_stake = 0;
+        for (slot, stake) in slots_and_stakes.iter() {
+            if *slot >= min_slot && *slot <= max_slot {
+                total_stake += stake;
+                if total_stake > supermajority_stake {
+                    return self
+                        .tick_hash_queue
+                        .read()
+                        .unwrap()
+                        .hash_height_to_timestamp(slot * self.ticks_per_slot());
+                }
+            }
+        }
+
+        None
     }
 
     /// Tell the bank which Entry IDs exist on the ledger. This function
diff --git a/runtime/src/hash_queue.rs b/runtime/src/hash_queue.rs
index c1cb531321..b30bb85159 100644
--- a/runtime/src/hash_queue.rs
+++ b/runtime/src/hash_queue.rs
@@ -88,32 +88,8 @@ impl HashQueue {
         self.last_hash = Some(*hash);
     }
 
-    /// Looks through a list of hash heights and stakes, and finds the latest
-    /// hash that has achieved confirmation
-    pub fn get_confirmation_timestamp(
-        &self,
-        hashes_and_stakes: &mut [(u64, u64)],
-        supermajority_stake: u64,
-    ) -> Option<u64> {
-        // Sort by hash height
-        hashes_and_stakes.sort_by(|a, b| a.0.cmp(&b.0));
-        let current_hash_height = self.hash_height;
-        let mut total = 0;
-        for (hash_height, stake) in hashes_and_stakes.iter() {
-            if current_hash_height >= *hash_height
-                && ((current_hash_height - hash_height) as usize) < MAX_RECENT_TICK_HASHES
-            {
-                total += stake;
-                if total > supermajority_stake {
-                    return self.hash_height_to_timestamp(*hash_height);
-                }
-            }
-        }
-        None
-    }
-
     /// Maps a hash height to a timestamp
-    fn hash_height_to_timestamp(&self, hash_height: u64) -> Option<u64> {
+    pub fn hash_height_to_timestamp(&self, hash_height: u64) -> Option<u64> {
         for entry in self.entries.values() {
             if entry.hash_height == hash_height {
                 return Some(entry.timestamp);
diff --git a/src/leader_confirmation_service.rs b/src/leader_confirmation_service.rs
index 6ca2f90e2d..57d1a0af39 100644
--- a/src/leader_confirmation_service.rs
+++ b/src/leader_confirmation_service.rs
@@ -37,30 +37,22 @@ impl LeaderConfirmationService {
         // the vote states
         let vote_states = bank.vote_states(|_, vote_state| leader_id != vote_state.delegate_id);
 
-        let mut ticks_and_stakes: Vec<(u64, u64)> = vote_states
+        let slots_and_stakes: Vec<(u64, u64)> = vote_states
             .iter()
             .filter_map(|(_, vote_state)| {
                 let validator_stake = bank.get_balance(&vote_state.delegate_id);
                 total_stake += validator_stake;
-                // Filter out any validators that don't have at least one vote
-                // by returning None
                 vote_state
                     .votes
                     .back()
-                    // A vote for a slot is like a vote for the last tick in that slot
-                    .map(|vote| {
-                        (
-                            (vote.slot_height + 1) * bank.ticks_per_slot() - 1,
-                            validator_stake,
-                        )
-                    })
+                    .map(|vote| (vote.slot_height, validator_stake))
             })
             .collect();
 
         let super_majority_stake = (2 * total_stake) / 3;
 
         if let Some(last_valid_validator_timestamp) =
-            bank.get_confirmation_timestamp(&mut ticks_and_stakes, super_majority_stake)
+            bank.get_confirmation_timestamp(slots_and_stakes, super_majority_stake)
         {
             return Ok(last_valid_validator_timestamp);
         }