Method update

miner/engine.go:231–309

update dispatches blocks.

()

// update dispatches blocks.
func (e *engine) update() {
	// Subscribe NewTxsEvent for tx pool
	e.txsSub = e.backend.TxPool().SubscribeNewTxsEvent(e.txsCh)
	// Subscribe events for blockchain
	e.chainLatestSub = e.backend.BlockChain().SubscribeChainLatestEvent(e.chainLatestCh)
	e.chainSideSub = e.backend.BlockChain().SubscribeChainSideEvent(e.chainSideCh)

	defer e.chainSideSub.Unsubscribe()
	defer e.chainLatestSub.Unsubscribe()
	defer e.txsSub.Unsubscribe()

	for {
		// A real event arrived, process interesting content

		select {
		// a new block has been inserted.  we start to mine based on this new tip.
		case <-e.chainLatestCh:

			log.Debug("now to commit new work", "now", time.Now())

			// commitNewWork must run no matter if it is mining, because pending block needs to be updated by commitNewWork
			e.commitNewWork()

			if atomic.LoadInt32(&e.mining) == 1 {
				// checks and tries to campaign if needed
				e.cons.TryCampaign()
			}

		// handle chainsideevent
		// we don't have uncle blocks
		case ev := <-e.chainSideCh:
			log.Warn("Got unexpected uncle block ", "hash", ev.Block.Hash().Hex())

		// Handle NewTxsEvent
		// add to the work (transaction set).  it's mainly for api use, e.g., pending block.
		case ev := <-e.txsCh:
			// Apply transactions to the pending state if we're *not* mining.
			// Note all transactions received may be compatible with transactions
			// already included in the current mining block. These transactions will
			// be automatically eliminated.
			if atomic.LoadInt32(&e.mining) == 0 {
				// critical section for current work
				e.currentMu.Lock()

				txs := make(map[common.Address]types.Transactions)
				for _, tx := range ev.Txs {
					// get the sender account
					acc, _ := types.Sender(e.currentWork.signer, tx)
					txs[acc] = append(txs[acc], tx)
				}
				txset := types.NewTransactionsByPriceAndNonce(e.currentWork.signer, txs)
				e.currentWork.commitTransactions(e.mux, txset, e.chain, e.coinbase, time.Now().Add(time.Second*10))
				e.updateSnapshot()
				e.currentMu.Unlock()
			}
		// System stopped
		case err := <-e.txsSub.Err():
			if err == nil {