add NewTxPoolHeadEvent

2 files changed, 11 insertions, 0 deletions

diff --git a/core/events.go b/core/events.go
index 09e9180..aa58d08 100644
--- a/core/events.go
+++ b/core/events.go
@@ -24,6 +24,9 @@ import (
 // NewTxsEvent is posted when a batch of transactions enter the transaction pool.
 type NewTxsEvent struct{ Txs []*types.Transaction }
 
+// NewTxPoolHeadEvent is posted when the pool head is updated.
+type NewTxPoolHeadEvent struct{ block *types.Block }
+
 // PendingLogsEvent is posted pre mining and notifies of pending logs.
 type PendingLogsEvent struct {
 	Logs []*types.Log
diff --git a/core/tx_pool.go b/core/tx_pool.go
index caabd5c..3454936 100644
--- a/core/tx_pool.go
+++ b/core/tx_pool.go
@@ -213,6 +213,7 @@ type TxPool struct {
 	chain       blockChain
 	gasPrice    *big.Int
 	txFeed      event.Feed
+	headFeed    event.Feed
 	scope       event.SubscriptionScope
 	signer      types.Signer
 	mu          sync.RWMutex
@@ -328,6 +329,7 @@ func (pool *TxPool) loop() {
 			if ev.Block != nil {
 				pool.requestReset(head.Header(), ev.Block.Header())
 				head = ev.Block
+				pool.headFeed.Send(NewTxPoolHeadEvent{head})
 			}
 
 		// System shutdown.
@@ -398,6 +400,12 @@ func (pool *TxPool) SubscribeNewTxsEvent(ch chan<- NewTxsEvent) event.Subscripti
 	return pool.scope.Track(pool.txFeed.Subscribe(ch))
 }
 
+// SubscribeNewHeadEvent registers a subscription of NewHeadEvent and
+// starts sending event to the given channel.
+func (pool *TxPool) SubscribeNewHeadEvent(ch chan<- NewTxPoolHeadEvent) event.Subscription {
+	return pool.scope.Track(pool.headFeed.Subscribe(ch))
+}
+
 // GasPrice returns the current gas price enforced by the transaction pool.
 func (pool *TxPool) GasPrice() *big.Int {
 	pool.mu.RLock()