core, consensus: pluggable consensus engines (#3817)

This commit adds pluggable consensus engines to go-ethereum. In short, it
introduces a generic consensus interface, and refactors the entire codebase to
use this interface.

2 files changed, 11 insertions, 3 deletions

diff --git a/cmd/geth/main.go b/cmd/geth/main.go
index cc6d3ac6a..e942d53c8 100644
--- a/cmd/geth/main.go
+++ b/cmd/geth/main.go
@@ -303,7 +303,15 @@ func startNode(ctx *cli.Context, stack *node.Node) {
 		if err := stack.Service(&ethereum); err != nil {
 			utils.Fatalf("ethereum service not running: %v", err)
 		}
-		if err := ethereum.StartMining(ctx.GlobalInt(utils.MinerThreadsFlag.Name)); err != nil {
+		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)
+			}
+		}
+		if err := ethereum.StartMining(); err != nil {
 			utils.Fatalf("Failed to start mining: %v", err)
 		}
 	}
diff --git a/cmd/geth/misccmd.go b/cmd/geth/misccmd.go
index 073c36beb..079f49310 100644
--- a/cmd/geth/misccmd.go
+++ b/cmd/geth/misccmd.go
@@ -26,9 +26,9 @@ import (
 	"strings"
 
 	"github.com/ethereum/go-ethereum/cmd/utils"
+	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/eth"
 	"github.com/ethereum/go-ethereum/params"
-	"github.com/ethereum/go-ethereum/pow"
 	"gopkg.in/urfave/cli.v1"
 )
 
@@ -87,7 +87,7 @@ func makedag(ctx *cli.Context) error {
 				utils.Fatalf("Can't find dir")
 			}
 			fmt.Println("making DAG, this could take awhile...")
-			pow.MakeDataset(blockNum, dir)
+			ethash.MakeDataset(blockNum, dir)
 		}
 	default:
 		wrongArgs()