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, 9 insertions, 9 deletions

diff --git a/eth/fetcher/fetcher.go b/eth/fetcher/fetcher.go
index d82f4f3e6..64a991069 100644
--- a/eth/fetcher/fetcher.go
+++ b/eth/fetcher/fetcher.go
@@ -52,8 +52,8 @@ type headerRequesterFn func(common.Hash) error
 // bodyRequesterFn is a callback type for sending a body retrieval request.
 type bodyRequesterFn func([]common.Hash) error
 
-// blockValidatorFn is a callback type to verify a block's header for fast propagation.
-type blockValidatorFn func(block *types.Block, parent *types.Block) error
+// headerVerifierFn is a callback type to verify a block's header for fast propagation.
+type headerVerifierFn func(header *types.Header) error
 
 // blockBroadcasterFn is a callback type for broadcasting a block to connected peers.
 type blockBroadcasterFn func(block *types.Block, propagate bool)
@@ -129,7 +129,7 @@ type Fetcher struct {
 
 	// Callbacks
 	getBlock       blockRetrievalFn   // Retrieves a block from the local chain
-	validateBlock  blockValidatorFn   // Checks if a block's headers have a valid proof of work
+	verifyHeader   headerVerifierFn   // Checks if a block's headers have a valid proof of work
 	broadcastBlock blockBroadcasterFn // Broadcasts a block to connected peers
 	chainHeight    chainHeightFn      // Retrieves the current chain's height
 	insertChain    chainInsertFn      // Injects a batch of blocks into the chain
@@ -144,7 +144,7 @@ type Fetcher struct {
 }
 
 // New creates a block fetcher to retrieve blocks based on hash announcements.
-func New(getBlock blockRetrievalFn, validateBlock blockValidatorFn, broadcastBlock blockBroadcasterFn, chainHeight chainHeightFn, insertChain chainInsertFn, dropPeer peerDropFn) *Fetcher {
+func New(getBlock blockRetrievalFn, verifyHeader headerVerifierFn, broadcastBlock blockBroadcasterFn, chainHeight chainHeightFn, insertChain chainInsertFn, dropPeer peerDropFn) *Fetcher {
 	return &Fetcher{
 		notify:         make(chan *announce),
 		inject:         make(chan *inject),
@@ -162,7 +162,7 @@ func New(getBlock blockRetrievalFn, validateBlock blockValidatorFn, broadcastBlo
 		queues:         make(map[string]int),
 		queued:         make(map[common.Hash]*inject),
 		getBlock:       getBlock,
-		validateBlock:  validateBlock,
+		verifyHeader:   verifyHeader,
 		broadcastBlock: broadcastBlock,
 		chainHeight:    chainHeight,
 		insertChain:    insertChain,
@@ -648,7 +648,7 @@ func (f *Fetcher) insert(peer string, block *types.Block) {
 			return
 		}
 		// Quickly validate the header and propagate the block if it passes
-		switch err := f.validateBlock(block, parent); err {
+		switch err := f.verifyHeader(block.Header()); err {
 		case nil:
 			// All ok, quickly propagate to our peers
 			propBroadcastOutTimer.UpdateSince(block.ReceivedAt)
diff --git a/eth/fetcher/fetcher_test.go b/eth/fetcher/fetcher_test.go
index 7a94241c6..85d2f8645 100644
--- a/eth/fetcher/fetcher_test.go
+++ b/eth/fetcher/fetcher_test.go
@@ -91,7 +91,7 @@ func newTester() *fetcherTester {
 		blocks: map[common.Hash]*types.Block{genesis.Hash(): genesis},
 		drops:  make(map[string]bool),
 	}
-	tester.fetcher = New(tester.getBlock, tester.verifyBlock, tester.broadcastBlock, tester.chainHeight, tester.insertChain, tester.dropPeer)
+	tester.fetcher = New(tester.getBlock, tester.verifyHeader, tester.broadcastBlock, tester.chainHeight, tester.insertChain, tester.dropPeer)
 	tester.fetcher.Start()
 
 	return tester
@@ -105,8 +105,8 @@ func (f *fetcherTester) getBlock(hash common.Hash) *types.Block {
 	return f.blocks[hash]
 }
 
-// verifyBlock is a nop placeholder for the block header verification.
-func (f *fetcherTester) verifyBlock(block *types.Block, parent *types.Block) error {
+// verifyHeader is a nop placeholder for the block header verification.
+func (f *fetcherTester) verifyHeader(header *types.Header) error {
 	return nil
 }