Implement fixed difficulty flag

cmd/geth/main.go

@@ -233,6 +233,7 @@ JavaScript API. See https://github.com/ethereum/go-ethereum/wiki/Javascipt-Conso
 		utils.GpobaseStepUpFlag,
 		utils.GpobaseCorrectionFactorFlag,
 		utils.ExtraDataFlag,
+        utils.FixedDifficultyFlag,
 	}
 	app.Flags = append(app.Flags, debug.Flags...)
 

cmd/utils/flags.go

@@ -392,6 +392,11 @@ var (
 		Usage: "Suggested gas price base correction factor (%)",
 		Value: 110,
 	}
+    FixedDifficultyFlag = cli.IntFlag{
+        Name:  "difficulty",
+        Usage: "Specify a fixed difficulty.",
+        Value: -1,
+    }
 )
 
 // MustMakeDataDir retrieves the currently requested data directory, terminating
@@ -801,7 +806,9 @@ func MustMakeChainConfig(ctx *cli.Context) *core.ChainConfig {
 	db := MakeChainDatabase(ctx)
 	defer db.Close()
 
-	return MustMakeChainConfigFromDb(ctx, db)
+	config := MustMakeChainConfigFromDb(ctx, db)
+    config.FixedDifficulty = ctx.GlobalInt(FixedDifficultyFlag.Name)
+    return config
 }
 
 // MustMakeChainConfigFromDb reads the chain configuration from the given database.

core/block_validator.go

@@ -254,7 +254,10 @@ func ValidateHeader(config *ChainConfig, pow pow.PoW, header *types.Header, pare
 // the difficulty that a new block should have when created at time
 // given the parent block's time and difficulty.
 func CalcDifficulty(config *ChainConfig, time, parentTime uint64, parentNumber, parentDiff *big.Int) *big.Int {
-	if config.IsHomestead(new(big.Int).Add(parentNumber, common.Big1)) {
+	if config.FixedDifficulty != -1 {
+        return big.NewInt(int64(config.FixedDifficulty))
+    }
+    if config.IsHomestead(new(big.Int).Add(parentNumber, common.Big1)) {
 		return calcDifficultyHomestead(time, parentTime, parentNumber, parentDiff)
 	} else {
 		return calcDifficultyFrontier(time, parentTime, parentNumber, parentDiff)

core/chain_makers.go

@@ -35,7 +35,7 @@ import (
 
 // MakeChainConfig returns a new ChainConfig with the ethereum default chain settings.
 func MakeChainConfig() *ChainConfig {
-	return &ChainConfig{HomesteadBlock: big.NewInt(0)}
+   return &ChainConfig{HomesteadBlock: big.NewInt(0), FixedDifficulty: -1}
 }
 
 // FakePow is a non-validating proof of work implementation.

core/config.go

@@ -34,6 +34,8 @@ type ChainConfig struct {
 	HomesteadBlock *big.Int // homestead switch block
 
 	VmConfig vm.Config `json:"-"`
+
+    FixedDifficulty int
 }
 
 // IsHomestead returns whether num is either equal to the homestead block or greater.

eth/backend.go

@@ -100,6 +100,8 @@ type Config struct {
 
 	TestGenesisBlock *types.Block   // Genesis block to seed the chain database with (testing only!)
 	TestGenesisState ethdb.Database // Genesis state to seed the database with (testing only!)
+
+    FixedDifficulty int
 }
 
 type Ethereum struct {
@@ -142,6 +144,8 @@ type Ethereum struct {
 	etherbase     common.Address
 	netVersionId  int
 	netRPCService *PublicNetAPI
+
+    fixedDifficulty int
 }
 
 func New(ctx *node.ServiceContext, config *Config) (*Ethereum, error) {

miner/miner.go

@@ -149,7 +149,9 @@ func (self *Miner) actuallyStart(coinbase common.Address, threads int) {
 }
 
 func (self *Miner) Stop() {
-	self.sub.Unsubscribe();
+	if(self.sub != nil) {
+        self.sub.Unsubscribe();
+    }
     self.worker.stop()
 	atomic.StoreInt32(&self.mining, 0)
 	atomic.StoreInt32(&self.shouldStart, 0)

wercker.yml

@@ -0,0 +1,19 @@
+box: golang
+build:
+  steps:
+    - setup-go-workspace
+    - script:
+        name: go build
+        code: |
+          make geth
+          BIN=/pipeline/source/build/bin/$WERCKER_GIT_BRANCH/`cat VERSION`
+          mkdir -p $BIN
+          cp build/bin/geth $BIN/geth
+deploy:
+  steps:
+  - s3sync:
+      source_dir:     build/bin 
+      delete-removed: false
+      bucket-url:     $AWS_BUCKET_URL
+      key-id:         $AWS_ACCESS_KEY_ID
+      key-secret:     $AWS_SECRET_ACCESS_KEY