From 2cde3e9fe8f23eaa2b88a8afb54ebf221615174e Mon Sep 17 00:00:00 2001
From: AnilChinchawale <anil24593@gmail.com>
Date: Fri, 22 Jun 2018 14:14:13 +0530
Subject: [PATCH] added MINING PERMISSION EVERY EPOCH BLOCK +1

---
 cmd/XDC/main.go | 48 ++++++++++++++++++++++++++++--------------------
 eth/backend.go  |  5 +++++
 2 files changed, 33 insertions(+), 20 deletions(-)

diff --git a/cmd/XDC/main.go b/cmd/XDC/main.go
index 732be48972..e14d541763 100644
--- a/cmd/XDC/main.go
+++ b/cmd/XDC/main.go
@@ -290,27 +290,35 @@ func startNode(ctx *cli.Context, stack *node.Node) {
 			utils.Fatalf("Ethereum service not running: %v", err)
 		}
 
-		// Mining only enabled for validator nodes
-		if ok, err := ethereum.ValidateMiner(); err != nil {
-			utils.Fatalf("Can't verify validator permission: %v", err)
-		} else if !ok {
-			log.Info("Only validator can mine blocks. Cancel mining on this node")
-			return
-		}
+		go func() {
+			for {
+				if ethereum.Checkpoint() {
+					// Mining only enabled for validator nodes
+					if ok, err := ethereum.ValidateMiner(); err != nil {
+						utils.Fatalf("Can't verify validator permission: %v", err)
+					} else if !ok {
+						log.Info("Only validator can mine blocks. Cancel mining on this node")
+						ethereum.StopMining()
+						continue
+					}
 
-		// Use a reduced number of threads if requested
-		if threads := ctx.GlobalInt(utils.MinerThreadsFlag.Name); threads > 0 {
-			type threaded interface {
-				SetThreads(threads int)
+					// Use a reduced number of threads if requested
+					if threads := ctx.GlobalInt(utils.MinerThreadsFlag.Name); threads > 0 {
+						type threaded interface {
+							SetThreads(threads int)
+						}
+						if th, ok := ethereum.Engine().(threaded); ok {
+							th.SetThreads(threads)
+						}
+					}
+					// Set the gas price to the limits from the CLI and start mining
+					ethereum.TxPool().SetGasPrice(utils.GlobalBig(ctx, utils.GasPriceFlag.Name))
+					if err := ethereum.StartMining(true); err != nil {
+						utils.Fatalf("Failed to start mining: %v", err)
+					}
+				}
 			}
-			if th, ok := ethereum.Engine().(threaded); ok {
-				th.SetThreads(threads)
-			}
-		}
-		// Set the gas price to the limits from the CLI and start mining
-		ethereum.TxPool().SetGasPrice(utils.GlobalBig(ctx, utils.GasPriceFlag.Name))
-		if err := ethereum.StartMining(true); err != nil {
-			utils.Fatalf("Failed to start mining: %v", err)
-		}
+		}()
 	}
 }
+		
diff --git a/eth/backend.go b/eth/backend.go
index f3b188cdbc..da5f4c9a32 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -356,6 +356,11 @@ func (s *Ethereum) ValidateMiner() (bool, error) {
 	return true, nil
 }
 
+func (s *Ethereum) Checkpoint() bool {
+	number := s.blockchain.CurrentHeader().Number.Uint64()
+	return number%s.chainConfig.Clique.Epoch == 1
+}
+
 func (s *Ethereum) StartMining(local bool) error {
 	eb, err := s.Etherbase()
 	if err != nil {