core: modify interface (#194)

* Add a new method to notify full node about round cutting.
* Modify interface to return error when preparing block

1 files changed, 2 insertions, 2 deletions

diff --git a/core/nonblocking.go b/core/nonblocking.go
index 9bedb4b..532bcb9 100644
--- a/core/nonblocking.go
+++ b/core/nonblocking.go
@@ -119,12 +119,12 @@ func (nb *nonBlocking) wait() {
 }
 
 // PreparePayload cannot be non-blocking.
-func (nb *nonBlocking) PreparePayload(position types.Position) []byte {
+func (nb *nonBlocking) PreparePayload(position types.Position) ([]byte, error) {
 	return nb.app.PreparePayload(position)
 }
 
 // PrepareWitness cannot be non-blocking.
-func (nb *nonBlocking) PrepareWitness(height uint64) types.Witness {
+func (nb *nonBlocking) PrepareWitness(height uint64) (types.Witness, error) {
 	return nb.app.PrepareWitness(height)
 }