Determine transaction indexes in PohRecorder; add field to WorkingBank

poh/src/poh_recorder.rs

@@ -191,6 +191,7 @@ pub struct WorkingBank {
     pub start: Arc<Instant>,
     pub min_tick_height: u64,
     pub max_tick_height: u64,
+    pub transaction_index: usize,
 }
 
 #[derive(Debug, PartialEq, Eq)]
@@ -501,6 +502,7 @@ impl PohRecorder {
             start: Arc::new(Instant::now()),
             min_tick_height: bank.tick_height(),
             max_tick_height: bank.max_tick_height(),
+            transaction_index: 0,
         };
         trace!("new working bank");
         assert_eq!(working_bank.bank.ticks_per_slot(), self.ticks_per_slot());
@@ -756,9 +758,9 @@ impl PohRecorder {
             self.flush_cache_no_tick_us += flush_cache_time.as_us();
             flush_cache_res?;
 
-            let working_bank = self
+            let mut working_bank = self
                 .working_bank
-                .as_ref()
+                .as_mut()
                 .ok_or(PohRecorderError::MaxHeightReached)?;
             if bank_slot != working_bank.bank.slot() {
                 return Err(PohRecorderError::MaxHeightReached);
@@ -774,6 +776,7 @@ impl PohRecorder {
             drop(poh_lock);
 
             if let Some(poh_entry) = record_mixin_res {
+                let num_transactions = transactions.len();
                 let (send_entry_res, send_entry_time) = measure!(
                     {
                         let entry = Entry {
@@ -788,7 +791,14 @@ impl PohRecorder {
                 );
                 self.send_entry_us += send_entry_time.as_us();
                 send_entry_res?;
-                return Ok(vec![]);
+                let transaction_index_next_batch = working_bank
+                    .transaction_index
+                    .saturating_add(num_transactions);
+                let transaction_indexes: Vec<_> =
+                    (working_bank.transaction_index..transaction_index_next_batch).collect();
+                working_bank.transaction_index = transaction_index_next_batch;
+                self.working_bank = Some(working_bank.clone());
+                return Ok(transaction_indexes);
             }
 
             // record() might fail if the next PoH hash needs to be a tick.  But that's ok, tick()