Expose the new leader schedule functionality from the bank.

Cargo.lock

@@ -2243,6 +2243,7 @@ dependencies = [
  "hashbrown 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_chacha 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.88 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.88 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.38 (registry+https://github.com/rust-lang/crates.io-index)",

runtime/Cargo.toml

@@ -15,6 +15,7 @@ fnv = "1.0.6"
 hashbrown = "0.1.8"
 log = "0.4.2"
 rand = "0.6.5"
+rand_chacha = "0.1.1"
 serde = "1.0.88"
 serde_derive = "1.0.88"
 serde_json = "1.0.38"

runtime/src/bank.rs

@@ -5,6 +5,7 @@
 
 use crate::accounts::{Accounts, ErrorCounters, InstructionAccounts, InstructionLoaders};
 use crate::last_id_queue::LastIdQueue;
+use crate::leader_schedule::LeaderSchedule;
 use crate::runtime::{self, RuntimeError};
 use crate::status_cache::StatusCache;
 use bincode::serialize;
@@ -675,7 +676,7 @@ impl Bank {
 
     /// Return the checkpointed bank that should be used to generate a leader schedule.
     /// Return None if a sufficiently old bank checkpoint doesn't exist.
-    pub fn leader_schedule_bank(&self) -> Option<Arc<Bank>> {
+    fn leader_schedule_bank(&self) -> Option<Arc<Bank>> {
         let epoch_slot_height = self.slot_height() - self.slot_index();
         let expected = epoch_slot_height.saturating_sub(self.leader_schedule_slot_offset);
         self.parents()
@@ -683,6 +684,19 @@ impl Bank {
             .find(|bank| bank.slot_height() <= expected)
     }
 
+    /// Return the leader schedule for the current epoch.
+    fn leader_schedule(&self) -> LeaderSchedule {
+        match self.leader_schedule_bank() {
+            None => LeaderSchedule::new_with_bank(self),
+            Some(bank) => LeaderSchedule::new_with_bank(&bank),
+        }
+    }
+
+    /// Return the leader for the current slot.
+    pub fn slot_leader(&self) -> Pubkey {
+        self.leader_schedule()[self.slot_index() as usize]
+    }
+
     /// Return the number of ticks since genesis.
     pub fn tick_height(&self) -> u64 {
         self.last_id_queue.read().unwrap().tick_height
@@ -1365,4 +1379,11 @@ mod tests {
             bank.merge_parents();
         }
     }
+
+    #[test]
+    fn test_bank_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);
+    }
 }

runtime/src/leader_schedule.rs

@@ -1,11 +1,11 @@
+use crate::bank::Bank;
 use rand::distributions::{Distribution, WeightedIndex};
 use rand::SeedableRng;
 use rand_chacha::ChaChaRng;
-use solana_runtime::bank::Bank;
 use solana_sdk::pubkey::Pubkey;
 use std::ops::Index;
 
-/// Round-robin leader schedule.
+/// Stake-weighted leader schedule for one epoch.
 #[derive(Debug, PartialEq)]
 pub struct LeaderSchedule {
     slot_leaders: Vec<Pubkey>,
@@ -43,27 +43,6 @@ 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 {
-    fn leader_schedule(&self) -> LeaderSchedule {
-        match self.leader_schedule_bank() {
-            None => LeaderSchedule::new_with_bank(self),
-            Some(bank) => LeaderSchedule::new_with_bank(&bank),
-        }
-    }
-
-    fn slot_leader(&self) -> Pubkey {
-        self.leader_schedule()[self.slot_index() as usize]
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -110,13 +89,5 @@ mod tests {
         let len = bank.slots_per_epoch() as usize;
         let expected: Vec<_> = iter::repeat(pubkey).take(len).collect();
         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);
     }
 }

runtime/src/lib.rs

@@ -2,6 +2,7 @@ mod accounts;
 pub mod bank;
 pub mod bloom;
 mod last_id_queue;
+mod leader_schedule;
 mod runtime;
 mod status_cache;
 

src/lib.rs

@@ -39,7 +39,6 @@ pub mod fullnode;
 pub mod gen_keys;
 pub mod gossip_service;
 pub mod leader_confirmation_service;
-pub mod leader_schedule;
 pub mod leader_scheduler;
 pub mod local_vote_signer_service;
 pub mod packet;