core: adapt highestVerifiedHeader to FastFinality (#2574)

core/blockchain.go

@@ -2387,26 +2387,11 @@ func (bc *BlockChain) updateHighestVerifiedHeader(header *types.Header) {
 	if header == nil || header.Number == nil {
 		return
 	}
-	currentHeader := bc.highestVerifiedHeader.Load()
-	if currentHeader == nil {
-		bc.highestVerifiedHeader.Store(types.CopyHeader(header))
-		return
-	}
-
-	newParentTD := bc.GetTd(header.ParentHash, header.Number.Uint64()-1)
-	if newParentTD == nil {
-		newParentTD = big.NewInt(0)
-	}
-	oldParentTD := bc.GetTd(currentHeader.ParentHash, currentHeader.Number.Uint64()-1)
-	if oldParentTD == nil {
-		oldParentTD = big.NewInt(0)
-	}
-	newTD := big.NewInt(0).Add(newParentTD, header.Difficulty)
-	oldTD := big.NewInt(0).Add(oldParentTD, currentHeader.Difficulty)
-
-	if newTD.Cmp(oldTD) > 0 {
+	currentBlock := bc.CurrentBlock()
+	reorg, err := bc.forker.ReorgNeededWithFastFinality(currentBlock, header)
+	if err == nil && reorg {
 		bc.highestVerifiedHeader.Store(types.CopyHeader(header))
-		return
+		log.Trace("updateHighestVerifiedHeader", "number", header.Number.Uint64(), "hash", header.Hash())
 	}
 }
 

core/forkchoice.go

@@ -86,9 +86,16 @@ func (f *ForkChoice) ReorgNeeded(current *types.Header, extern *types.Header) (b
 		localTD  = f.chain.GetTd(current.Hash(), current.Number.Uint64())
 		externTd = f.chain.GetTd(extern.Hash(), extern.Number.Uint64())
 	)
-	if localTD == nil || externTd == nil {
+	if localTD == nil {
 		return false, errors.New("missing td")
 	}
+	if externTd == nil {
+		ptd := f.chain.GetTd(extern.ParentHash, extern.Number.Uint64()-1)
+		if ptd == nil {
+			return false, consensus.ErrUnknownAncestor
+		}
+		externTd = new(big.Int).Add(ptd, extern.Difficulty)
+	}
 	// Accept the new header as the chain head if the transition
 	// is already triggered. We assume all the headers after the
 	// transition come from the trusted consensus layer.