Method InsertChain

core/blockchain.go:1182–1255

InsertChain attempts to insert the given batch of blocks in to the canonical chain or, otherwise, create a fork. If an error is returned it will return the index number of the failing block as well an error describing what went wrong. After insertion is done, all accumulated events will be fired.

(chain types.Blocks)

//
// After insertion is done, all accumulated events will be fired.
func (bc *BlockChain) InsertChain(chain types.Blocks) (int, error) {
	bc.insertChainProtectLock.Lock()
	defer bc.insertChainProtectLock.Unlock()

	// do not stop blockchain if the insertion is not finished
	bc.wg.Add(1)
	defer bc.wg.Done()

	if len(chain) == 0 {
		return 0, nil
	}

	var (
		last    = chain[len(chain)-1].NumberU64()
		current = bc.CurrentBlock().NumberU64()
	)

	// if the last block is already in local chain, return early
	if last <= current {
		return len(chain), nil
	}

	// find the first block that is not in local chain
	var outset int
	for index, block := range chain {
		if block.NumberU64() > current {
			outset = index
			break
		}
	}

	// remove useless prefix
	chain = chain[outset:]

	if bc.mux != nil {
		bc.mux.Post(InsertionStartEvent{})
		log.Debug("posted InsertionStartEvent when inserting blocks")

		defer func() {
			bc.mux.Post(InsertionDoneEvent{})
			log.Debug("posted InsertionDoneEvent when inserted blocks")
		}()
	}

	_, headN := bc.KnownHead()

	// if the first item in the chain is in range (head-pivot, head), insert one by one.
	if headN < configs.DefaultFullSyncPivot || chain[len(chain)-1].NumberU64() > headN-configs.DefaultFullSyncPivot {

		rN, rErr := 0, error(nil)

		for iter := 0; iter < len(chain); iter++ {
			n, events, logs, err := bc.insertChain(chain[iter : iter+1])

			rN, rErr = rN+n, err

			bc.CommitStateDB()
			bc.PostChainEvents(events, logs)