Merge pull request #989 from obscuren/develop

core, miner: fork resolving and restart miner after sync op

4 files changed, 20 insertions, 9 deletions

diff --git a/cmd/geth/admin.go b/cmd/geth/admin.go
index 91a336cbb..ebdf3512a 100644
--- a/cmd/geth/admin.go
+++ b/cmd/geth/admin.go
@@ -288,7 +288,7 @@ func (js *jsre) startMining(call otto.FunctionCall) otto.Value {
 			return otto.FalseValue()
 		}
 	} else {
-		threads = 4
+		threads = int64(js.ethereum.MinerThreads)
 	}
 
 	err = js.ethereum.StartMining(int(threads))
diff --git a/core/chain_manager.go b/core/chain_manager.go
index a0839ad41..2e8eb927d 100644
--- a/core/chain_manager.go
+++ b/core/chain_manager.go
@@ -577,10 +577,10 @@ func (self *ChainManager) InsertChain(chain types.Blocks) (int, error) {
 			// Compare the TD of the last known block in the canonical chain to make sure it's greater.
 			// At this point it's possible that a different chain (fork) becomes the new canonical chain.
 			if block.Td.Cmp(self.td) > 0 {
-				// Check for chain forks. If H(block.num - 1) != block.parent, we're on a fork and need to do some merging
-				if previous := self.getBlockByNumber(block.NumberU64() - 1); previous.Hash() != block.ParentHash() {
+				// chain fork
+				if block.ParentHash() != cblock.Hash() {
 					// during split we merge two different chains and create the new canonical chain
-					self.merge(previous, block)
+					self.merge(cblock, block)
 
 					queue[i] = ChainSplitEvent{block, logs}
 					queueEvent.splitCount++
@@ -641,9 +641,17 @@ func (self *ChainManager) diff(oldBlock, newBlock *types.Block) types.Blocks {
 		oldStart    = oldBlock
 		newStart    = newBlock
 	)
-	// first find common number
-	for newBlock = newBlock; newBlock.NumberU64() != oldBlock.NumberU64(); newBlock = self.GetBlock(newBlock.ParentHash()) {
-		newChain = append(newChain, newBlock)
+
+	// first reduce whoever is higher bound
+	if oldBlock.NumberU64() > newBlock.NumberU64() {
+		// reduce old chain
+		for oldBlock = oldBlock; oldBlock.NumberU64() != newBlock.NumberU64(); oldBlock = self.GetBlock(oldBlock.ParentHash()) {
+		}
+	} else {
+		// reduce new chain and append new chain blocks for inserting later on
+		for newBlock = newBlock; newBlock.NumberU64() != oldBlock.NumberU64(); newBlock = self.GetBlock(newBlock.ParentHash()) {
+			newChain = append(newChain, newBlock)
+		}
 	}
 
 	numSplit := newBlock.Number()
@@ -669,7 +677,7 @@ func (self *ChainManager) diff(oldBlock, newBlock *types.Block) types.Blocks {
 func (self *ChainManager) merge(oldBlock, newBlock *types.Block) {
 	newChain := self.diff(oldBlock, newBlock)
 
-	// insert blocks
+	// insert blocks. Order does not matter. Last block will be written in ImportChain itself which creates the new head properly
 	for _, block := range newChain {
 		self.insert(block)
 	}
diff --git a/eth/backend.go b/eth/backend.go
index 064018955..a7107f8d8 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -190,6 +190,7 @@ type Ethereum struct {
 	// logger logger.LogSystem
 
 	Mining        bool
+	MinerThreads  int
 	NatSpec       bool
 	DataDir       string
 	etherbase     common.Address
@@ -262,6 +263,7 @@ func New(config *Config) (*Ethereum, error) {
 		ethVersionId:    config.ProtocolVersion,
 		netVersionId:    config.NetworkId,
 		NatSpec:         config.NatSpec,
+		MinerThreads:    config.MinerThreads,
 	}
 
 	eth.chainManager = core.NewChainManager(blockDb, stateDb, eth.EventMux())
diff --git a/miner/miner.go b/miner/miner.go
index 359be4032..19d39a605 100644
--- a/miner/miner.go
+++ b/miner/miner.go
@@ -47,6 +47,7 @@ func (self *Miner) update() {
 			atomic.StoreInt32(&self.canStart, 0)
 			if self.Mining() {
 				self.Stop()
+				atomic.StoreInt32(&self.shouldStart, 1)
 				glog.V(logger.Info).Infoln("Mining operation aborted due to sync operation")
 			}
 		case downloader.DoneEvent, downloader.FailedEvent:
@@ -100,7 +101,7 @@ func (self *Miner) Stop() {
 }
 
 func (self *Miner) Register(agent Agent) {
-	if atomic.LoadInt32(&self.mining) == 0 {
+	if self.Mining() {
 		agent.Start()
 	}