From 264f502ed784cd9becec19c48f0b8d701be4fede Mon Sep 17 00:00:00 2001
From: Greg Fitzgerald <greg@solana.com>
Date: Sat, 23 Feb 2019 14:43:34 -0700
Subject: [PATCH] Query the bank for the current slot leader

---
 src/leader_schedule.rs | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/leader_schedule.rs b/src/leader_schedule.rs
index 468aa65e4..8ee8a7913 100644
--- a/src/leader_schedule.rs
+++ b/src/leader_schedule.rs
@@ -55,6 +55,9 @@ impl Index<usize> for LeaderSchedule {
 pub trait LeaderScheduleUtil {
     /// Return the leader schedule for the current epoch.
     fn leader_schedule(&self) -> LeaderSchedule;
+
+    /// Return the leader id for the current slot.
+    fn slot_leader(&self) -> Pubkey;
 }
 
 impl LeaderScheduleUtil for Bank {
@@ -64,6 +67,10 @@ impl LeaderScheduleUtil for Bank {
             Some(bank) => LeaderSchedule::new_with_bank(&bank),
         }
     }
+
+    fn slot_leader(&self) -> Pubkey {
+        self.leader_schedule()[self.slot_index() as usize]
+    }
 }
 
 #[cfg(test)]
@@ -114,4 +121,11 @@ mod tests {
         assert_eq!(leader_schedule.slot_leaders, expected);
         assert_eq!(bank.leader_schedule().slot_leaders, expected); // Same thing, but with the trait
     }
+
+    #[test]
+    fn test_leader_schedule_slot_leader_basic() {
+        let pubkey = Keypair::new().pubkey();
+        let bank = Bank::new(&GenesisBlock::new_with_leader(2, pubkey, 2).0);
+        assert_eq!(bank.slot_leader(), pubkey);
+    }
 }