// Tests block storage and retrieval operations.
func TestBlockStorage(t *testing.T) {
	db, _ := ethdb.NewMemDatabase()

	// Create a test block to move around the database and make sure it's really new
	block := types.NewBlockWithHeader(&types.Header{
		Extra:       []byte("test block"),
		UncleHash:   types.EmptyUncleHash,
		TxHash:      types.EmptyRootHash,
		ReceiptHash: types.EmptyRootHash,
	})
	if entry := GetBlock(db, block.Hash()); entry != nil {
		t.Fatalf("Non existent block returned: %v", entry)
	}
	if entry := GetHeader(db, block.Hash()); entry != nil {
		t.Fatalf("Non existent header returned: %v", entry)
	}
	if entry := GetBody(db, block.Hash()); entry != nil {
		t.Fatalf("Non existent body returned: %v", entry)
	}
	// Write and verify the block in the database
	if err := WriteBlock(db, block); err != nil {
		t.Fatalf("Failed to write block into database: %v", err)
	}
	if entry := GetBlock(db, block.Hash()); entry == nil {
		t.Fatalf("Stored block not found")
	} else if entry.Hash() != block.Hash() {
		t.Fatalf("Retrieved block mismatch: have %v, want %v", entry, block)
	}
	if entry := GetHeader(db, block.Hash()); entry == nil {
		t.Fatalf("Stored header not found")
	} else if entry.Hash() != block.Header().Hash() {
		t.Fatalf("Retrieved header mismatch: have %v, want %v", entry, block.Header())
	}
	if entry := GetBody(db, block.Hash()); entry == nil {
		t.Fatalf("Stored body not found")
	} else if types.DeriveSha(types.Transactions(entry.Transactions)) != types.DeriveSha(block.Transactions()) || types.CalcUncleHash(entry.Uncles) != types.CalcUncleHash(block.Uncles()) {
		t.Fatalf("Retrieved body mismatch: have %v, want %v", entry, &types.Body{block.Transactions(), block.Uncles()})
	}
	// Delete the block and verify the execution
	DeleteBlock(db, block.Hash())
	if entry := GetBlock(db, block.Hash()); entry != nil {
		t.Fatalf("Deleted block returned: %v", entry)
	}
	if entry := GetHeader(db, block.Hash()); entry != nil {
		t.Fatalf("Deleted header returned: %v", entry)
	}
	if entry := GetBody(db, block.Hash()); entry != nil {
		t.Fatalf("Deleted body returned: %v", entry)
	}
}

// Reserve reserves a set of headers for the given peer, skipping any previously
// failed download. Beside the next batch of needed fetches, it also returns a
// flag whether empty blocks were queued requiring processing.
func (q *queue) Reserve(p *peer, count int) (*fetchRequest, bool, error) {
	q.lock.Lock()
	defer q.lock.Unlock()

	// Short circuit if the pool has been depleted, or if the peer's already
	// downloading something (sanity check not to corrupt state)
	if q.headerQueue.Empty() {
		return nil, false, nil
	}
	if _, ok := q.pendPool[p.id]; ok {
		return nil, false, nil
	}
	// Calculate an upper limit on the bodies we might fetch (i.e. throttling)
	space := len(q.blockCache) - len(q.blockPool)
	for _, request := range q.pendPool {
		space -= len(request.Headers)
	}
	// Retrieve a batch of headers, skipping previously failed ones
	send := make([]*types.Header, 0, count)
	skip := make([]*types.Header, 0)

	process := false
	for proc := 0; proc < space && len(send) < count && !q.headerQueue.Empty(); proc++ {
		header := q.headerQueue.PopItem().(*types.Header)

		// If the header defines an empty block, deliver straight
		if header.TxHash == types.DeriveSha(types.Transactions{}) && header.UncleHash == types.CalcUncleHash([]*types.Header{}) {
			if err := q.enqueue("", types.NewBlockWithHeader(header)); err != nil {
				return nil, false, errInvalidChain
			}
			delete(q.headerPool, header.Hash())
			process, space, proc = true, space-1, proc-1
			continue
		}
		// If it's a content block, add to the body fetch request
		if p.ignored.Has(header.Hash()) {
			skip = append(skip, header)
		} else {
			send = append(send, header)
		}
	}
	// Merge all the skipped headers back
	for _, header := range skip {
		q.headerQueue.Push(header, -float32(header.Number.Uint64()))
	}
	// Assemble and return the block download request
	if len(send) == 0 {
		return nil, process, nil
	}
	request := &fetchRequest{
		Peer:    p,
		Headers: send,
		Time:    time.Now(),
	}
	q.pendPool[p.id] = request

	return request, process, nil
}

// DeliverReceipts injects a receipt retrieval response into the results queue.
// The method returns the number of transaction receipts accepted from the delivery
// and also wakes any threads waiting for data delivery.
func (q *queue) DeliverReceipts(id string, receiptList [][]*types.Receipt) (int, error) {
	q.lock.Lock()
	defer q.lock.Unlock()

	reconstruct := func(header *types.Header, index int, result *fetchResult) error {
		if types.DeriveSha(types.Receipts(receiptList[index])) != header.ReceiptHash {
			return errInvalidReceipt
		}
		result.Receipts = receiptList[index]
		return nil
	}
	return q.deliver(id, q.receiptTaskPool, q.receiptTaskQueue, q.receiptPendPool, q.receiptDonePool, receiptReqTimer, len(receiptList), reconstruct)
}

// Tests block body storage and retrieval operations.
func TestBodyStorage(t *testing.T) {
	db, _ := ethdb.NewMemDatabase()

	// Create a test body to move around the database and make sure it's really new
	body := &types.Body{Uncles: []*types.Header{{Extra: []byte("test header")}}}

	hasher := sha3.NewKeccak256()
	rlp.Encode(hasher, body)
	hash := common.BytesToHash(hasher.Sum(nil))

	if entry := GetBody(db, hash); entry != nil {
		t.Fatalf("Non existent body returned: %v", entry)
	}
	// Write and verify the body in the database
	if err := WriteBody(db, hash, body); err != nil {
		t.Fatalf("Failed to write body into database: %v", err)
	}
	if entry := GetBody(db, hash); entry == nil {
		t.Fatalf("Stored body not found")
	} else if types.DeriveSha(types.Transactions(entry.Transactions)) != types.DeriveSha(types.Transactions(body.Transactions)) || types.CalcUncleHash(entry.Uncles) != types.CalcUncleHash(body.Uncles) {
		t.Fatalf("Retrieved body mismatch: have %v, want %v", entry, body)
	}
	if entry := GetBodyRLP(db, hash); entry == nil {
		t.Fatalf("Stored body RLP not found")
	} else {
		hasher := sha3.NewKeccak256()
		hasher.Write(entry)

		if calc := common.BytesToHash(hasher.Sum(nil)); calc != hash {
			t.Fatalf("Retrieved RLP body mismatch: have %v, want %v", entry, body)
		}
	}
	// Delete the body and verify the execution
	DeleteBody(db, hash)
	if entry := GetBody(db, hash); entry != nil {
		t.Fatalf("Deleted body returned: %v", entry)
	}
}

// DeliverBodies injects a block body retrieval response into the results queue.
// The method returns the number of blocks bodies accepted from the delivery and
// also wakes any threads waiting for data delivery.
func (q *queue) DeliverBodies(id string, txLists [][]*types.Transaction, uncleLists [][]*types.Header) (int, error) {
	q.lock.Lock()
	defer q.lock.Unlock()

	reconstruct := func(header *types.Header, index int, result *fetchResult) error {
		if types.DeriveSha(types.Transactions(txLists[index])) != header.TxHash || types.CalcUncleHash(uncleLists[index]) != header.UncleHash {
			return errInvalidBody
		}
		result.Transactions = txLists[index]
		result.Uncles = uncleLists[index]
		return nil
	}
	return q.deliver(id, q.blockTaskPool, q.blockTaskQueue, q.blockPendPool, q.blockDonePool, bodyReqTimer, len(txLists), reconstruct)
}

// ValidateBlock validates the given block's header and uncles and verifies the
// the block header's transaction and uncle roots.
//
// ValidateBlock does not validate the header's pow. The pow work validated
// separately so we can process them in parallel.
//
// ValidateBlock also validates and makes sure that any previous state (or present)
// state that might or might not be present is checked to make sure that fast
// sync has done it's job proper. This prevents the block validator form accepting
// false positives where a header is present but the state is not.
func (v *BlockValidator) ValidateBlock(block *types.Block) error {
	if v.bc.HasBlock(block.Hash()) {
		if _, err := state.New(block.Root(), v.bc.chainDb); err == nil {
			return &KnownBlockError{block.Number(), block.Hash()}
		}
	}
	parent := v.bc.GetBlock(block.ParentHash())
	if parent == nil {
		return ParentError(block.ParentHash())
	}
	if _, err := state.New(parent.Root(), v.bc.chainDb); err != nil {
		return ParentError(block.ParentHash())
	}

	header := block.Header()
	// validate the block header
	if err := ValidateHeader(v.config, v.Pow, header, parent.Header(), false, false); err != nil {
		return err
	}
	// verify the uncles are correctly rewarded
	if err := v.VerifyUncles(block, parent); err != nil {
		return err
	}

	// Verify UncleHash before running other uncle validations
	unclesSha := types.CalcUncleHash(block.Uncles())
	if unclesSha != header.UncleHash {
		return fmt.Errorf("invalid uncles root hash. received=%x calculated=%x", header.UncleHash, unclesSha)
	}

	// The transactions Trie's root (R = (Tr [[i, RLP(T1)], [i, RLP(T2)], ... [n, RLP(Tn)]]))
	// can be used by light clients to make sure they've received the correct Txs
	txSha := types.DeriveSha(block.Transactions())
	if txSha != header.TxHash {
		return fmt.Errorf("invalid transaction root hash. received=%x calculated=%x", header.TxHash, txSha)
	}

	return nil
}

// ValidateState validates the various changes that happen after a state
// transition, such as amount of used gas, the receipt roots and the state root
// itself. ValidateState returns a database batch if the validation was a success
// otherwise nil and an error is returned.
func (v *BlockValidator) ValidateState(block, parent *types.Block, statedb *state.StateDB, receipts types.Receipts, usedGas *big.Int) (err error) {
	header := block.Header()
	if block.GasUsed().Cmp(usedGas) != 0 {
		return ValidationError(fmt.Sprintf("gas used error (%v / %v)", block.GasUsed(), usedGas))
	}
	// Validate the received block's bloom with the one derived from the generated receipts.
	// For valid blocks this should always validate to true.
	rbloom := types.CreateBloom(receipts)
	if rbloom != header.Bloom {
		return fmt.Errorf("unable to replicate block's bloom=%x vs calculated bloom=%x", header.Bloom, rbloom)
	}
	// Tre receipt Trie's root (R = (Tr [[H1, R1], ... [Hn, R1]]))
	receiptSha := types.DeriveSha(receipts)
	if receiptSha != header.ReceiptHash {
		return fmt.Errorf("invalid receipt root hash. received=%x calculated=%x", header.ReceiptHash, receiptSha)
	}
	// Validate the state root against the received state root and throw
	// an error if they don't match.
	if root := statedb.IntermediateRoot(); header.Root != root {
		return fmt.Errorf("invalid merkle root: header=%x computed=%x", header.Root, root)
	}
	return nil
}

// Tests that fast importing a block chain produces the same chain data as the
// classical full block processing.
func TestFastVsFullChains(t *testing.T) {
	// Configure and generate a sample block chain
	var (
		gendb, _ = ethdb.NewMemDatabase()
		key, _   = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
		address  = crypto.PubkeyToAddress(key.PublicKey)
		funds    = big.NewInt(1000000000)
		genesis  = GenesisBlockForTesting(gendb, address, funds)
	)
	blocks, receipts := GenerateChain(genesis, gendb, 1024, func(i int, block *BlockGen) {
		block.SetCoinbase(common.Address{0x00})

		// If the block number is multiple of 3, send a few bonus transactions to the miner
		if i%3 == 2 {
			for j := 0; j < i%4+1; j++ {
				tx, err := types.NewTransaction(block.TxNonce(address), common.Address{0x00}, big.NewInt(1000), params.TxGas, nil, nil).SignECDSA(key)
				if err != nil {
					panic(err)
				}
				block.AddTx(tx)
			}
		}
		// If the block number is a multiple of 5, add a few bonus uncles to the block
		if i%5 == 5 {
			block.AddUncle(&types.Header{ParentHash: block.PrevBlock(i - 1).Hash(), Number: big.NewInt(int64(i - 1))})
		}
	})
	// Import the chain as an archive node for the comparison baseline
	archiveDb, _ := ethdb.NewMemDatabase()
	WriteGenesisBlockForTesting(archiveDb, GenesisAccount{address, funds})

	archive, _ := NewBlockChain(archiveDb, FakePow{}, new(event.TypeMux))

	if n, err := archive.InsertChain(blocks); err != nil {
		t.Fatalf("failed to process block %d: %v", n, err)
	}
	// Fast import the chain as a non-archive node to test
	fastDb, _ := ethdb.NewMemDatabase()
	WriteGenesisBlockForTesting(fastDb, GenesisAccount{address, funds})
	fast, _ := NewBlockChain(fastDb, FakePow{}, new(event.TypeMux))

	headers := make([]*types.Header, len(blocks))
	for i, block := range blocks {
		headers[i] = block.Header()
	}
	if n, err := fast.InsertHeaderChain(headers, 1); err != nil {
		t.Fatalf("failed to insert header %d: %v", n, err)
	}
	if n, err := fast.InsertReceiptChain(blocks, receipts); err != nil {
		t.Fatalf("failed to insert receipt %d: %v", n, err)
	}
	// Iterate over all chain data components, and cross reference
	for i := 0; i < len(blocks); i++ {
		num, hash := blocks[i].NumberU64(), blocks[i].Hash()

		if ftd, atd := fast.GetTd(hash), archive.GetTd(hash); ftd.Cmp(atd) != 0 {
			t.Errorf("block #%d [%x]: td mismatch: have %v, want %v", num, hash, ftd, atd)
		}
		if fheader, aheader := fast.GetHeader(hash), archive.GetHeader(hash); fheader.Hash() != aheader.Hash() {
			t.Errorf("block #%d [%x]: header mismatch: have %v, want %v", num, hash, fheader, aheader)
		}
		if fblock, ablock := fast.GetBlock(hash), archive.GetBlock(hash); fblock.Hash() != ablock.Hash() {
			t.Errorf("block #%d [%x]: block mismatch: have %v, want %v", num, hash, fblock, ablock)
		} else if types.DeriveSha(fblock.Transactions()) != types.DeriveSha(ablock.Transactions()) {
			t.Errorf("block #%d [%x]: transactions mismatch: have %v, want %v", num, hash, fblock.Transactions(), ablock.Transactions())
		} else if types.CalcUncleHash(fblock.Uncles()) != types.CalcUncleHash(ablock.Uncles()) {
			t.Errorf("block #%d [%x]: uncles mismatch: have %v, want %v", num, hash, fblock.Uncles(), ablock.Uncles())
		}
		if freceipts, areceipts := GetBlockReceipts(fastDb, hash), GetBlockReceipts(archiveDb, hash); types.DeriveSha(freceipts) != types.DeriveSha(areceipts) {
			t.Errorf("block #%d [%x]: receipts mismatch: have %v, want %v", num, hash, freceipts, areceipts)
		}
	}
	// Check that the canonical chains are the same between the databases
	for i := 0; i < len(blocks)+1; i++ {
		if fhash, ahash := GetCanonicalHash(fastDb, uint64(i)), GetCanonicalHash(archiveDb, uint64(i)); fhash != ahash {
			t.Errorf("block #%d: canonical hash mismatch: have %v, want %v", i, fhash, ahash)
		}
	}
}

func (sm *BlockProcessor) processWithParent(block, parent *types.Block) (logs state.Logs, receipts types.Receipts, err error) {
	// Create a new state based on the parent's root (e.g., create copy)
	state := state.New(parent.Root(), sm.chainDb)
	header := block.Header()
	uncles := block.Uncles()
	txs := block.Transactions()

	// Block validation
	if err = ValidateHeader(sm.Pow, header, parent.Header(), false, false); err != nil {
		return
	}

	// There can be at most two uncles
	if len(uncles) > 2 {
		return nil, nil, ValidationError("Block can only contain maximum 2 uncles (contained %v)", len(uncles))
	}

	receipts, err = sm.TransitionState(state, parent, block, false)
	if err != nil {
		return
	}

	// Validate the received block's bloom with the one derived from the generated receipts.
	// For valid blocks this should always validate to true.
	rbloom := types.CreateBloom(receipts)
	if rbloom != header.Bloom {
		err = fmt.Errorf("unable to replicate block's bloom=%x", rbloom)
		return
	}

	// The transactions Trie's root (R = (Tr [[i, RLP(T1)], [i, RLP(T2)], ... [n, RLP(Tn)]]))
	// can be used by light clients to make sure they've received the correct Txs
	txSha := types.DeriveSha(txs)
	if txSha != header.TxHash {
		err = fmt.Errorf("invalid transaction root hash. received=%x calculated=%x", header.TxHash, txSha)
		return
	}

	// Tre receipt Trie's root (R = (Tr [[H1, R1], ... [Hn, R1]]))
	receiptSha := types.DeriveSha(receipts)
	if receiptSha != header.ReceiptHash {
		err = fmt.Errorf("invalid receipt root hash. received=%x calculated=%x", header.ReceiptHash, receiptSha)
		return
	}

	// Verify UncleHash before running other uncle validations
	unclesSha := types.CalcUncleHash(uncles)
	if unclesSha != header.UncleHash {
		err = fmt.Errorf("invalid uncles root hash. received=%x calculated=%x", header.UncleHash, unclesSha)
		return
	}

	// Verify uncles
	if err = sm.VerifyUncles(state, block, parent); err != nil {
		return
	}
	// Accumulate static rewards; block reward, uncle's and uncle inclusion.
	AccumulateRewards(state, header, uncles)

	// Commit state objects/accounts to a temporary trie (does not save)
	// used to calculate the state root.
	state.SyncObjects()
	if header.Root != state.Root() {
		err = fmt.Errorf("invalid merkle root. received=%x got=%x", header.Root, state.Root())
		return
	}

	// Sync the current block's state to the database
	state.Sync()

	return state.Logs(), receipts, nil
}

//.........这里部分代码省略.........
		case filter := <-f.headerFilter:
			// Headers arrived from a remote peer. Extract those that were explicitly
			// requested by the fetcher, and return everything else so it's delivered
			// to other parts of the system.
			var task *headerFilterTask
			select {
			case task = <-filter:
			case <-f.quit:
				return
			}
			headerFilterInMeter.Mark(int64(len(task.headers)))

			// Split the batch of headers into unknown ones (to return to the caller),
			// known incomplete ones (requiring body retrievals) and completed blocks.
			unknown, incomplete, complete := []*types.Header{}, []*announce{}, []*types.Block{}
			for _, header := range task.headers {
				hash := header.Hash()

				// Filter fetcher-requested headers from other synchronisation algorithms
				if announce := f.fetching[hash]; announce != nil && f.fetched[hash] == nil && f.completing[hash] == nil && f.queued[hash] == nil {
					// If the delivered header does not match the promised number, drop the announcer
					if header.Number.Uint64() != announce.number {
						glog.V(logger.Detail).Infof("[eth/62] Peer %s: invalid block number for [%x…]: announced %d, provided %d", announce.origin, header.Hash().Bytes()[:4], announce.number, header.Number.Uint64())
						f.dropPeer(announce.origin)
						f.forgetHash(hash)
						continue
					}
					// Only keep if not imported by other means
					if f.getBlock(hash) == nil {
						announce.header = header
						announce.time = task.time

						// If the block is empty (header only), short circuit into the final import queue
						if header.TxHash == types.DeriveSha(types.Transactions{}) && header.UncleHash == types.CalcUncleHash([]*types.Header{}) {
							glog.V(logger.Detail).Infof("[eth/62] Peer %s: block #%d [%x…] empty, skipping body retrieval", announce.origin, header.Number.Uint64(), header.Hash().Bytes()[:4])

							block := types.NewBlockWithHeader(header)
							block.ReceivedAt = task.time

							complete = append(complete, block)
							f.completing[hash] = announce
							continue
						}
						// Otherwise add to the list of blocks needing completion
						incomplete = append(incomplete, announce)
					} else {
						glog.V(logger.Detail).Infof("[eth/62] Peer %s: block #%d [%x…] already imported, discarding header", announce.origin, header.Number.Uint64(), header.Hash().Bytes()[:4])
						f.forgetHash(hash)
					}
				} else {
					// Fetcher doesn't know about it, add to the return list
					unknown = append(unknown, header)
				}
			}
			headerFilterOutMeter.Mark(int64(len(unknown)))
			select {
			case filter <- &headerFilterTask{headers: unknown, time: task.time}:
			case <-f.quit:
				return
			}
			// Schedule the retrieved headers for body completion
			for _, announce := range incomplete {
				hash := announce.header.Hash()
				if _, ok := f.completing[hash]; ok {
					continue
				}

func (sm *BlockProcessor) processWithParent(block, parent *types.Block) (logs state.Logs, err error) {
	sm.lastAttemptedBlock = block

	// Create a new state based on the parent's root (e.g., create copy)
	state := state.New(parent.Root(), sm.db)

	// Block validation
	if err = sm.ValidateHeader(block.Header(), parent.Header()); err != nil {
		return
	}

	// There can be at most two uncles
	if len(block.Uncles()) > 2 {
		return nil, ValidationError("Block can only contain one uncle (contained %v)", len(block.Uncles()))
	}

	receipts, err := sm.TransitionState(state, parent, block, false)
	if err != nil {
		return
	}

	header := block.Header()

	// Validate the received block's bloom with the one derived from the generated receipts.
	// For valid blocks this should always validate to true.
	rbloom := types.CreateBloom(receipts)
	if rbloom != header.Bloom {
		err = fmt.Errorf("unable to replicate block's bloom=%x", rbloom)
		return
	}

	// The transactions Trie's root (R = (Tr [[i, RLP(T1)], [i, RLP(T2)], ... [n, RLP(Tn)]]))
	// can be used by light clients to make sure they've received the correct Txs
	txSha := types.DeriveSha(block.Transactions())
	if txSha != header.TxHash {
		err = fmt.Errorf("invalid transaction root hash. received=%x calculated=%x", header.TxHash, txSha)
		return
	}

	// Tre receipt Trie's root (R = (Tr [[H1, R1], ... [Hn, R1]]))
	receiptSha := types.DeriveSha(receipts)
	if receiptSha != header.ReceiptHash {
		err = fmt.Errorf("invalid receipt root hash. received=%x calculated=%x", header.ReceiptHash, receiptSha)
		return
	}

	// Verify UncleHash before running other uncle validations
	unclesSha := block.CalculateUnclesHash()
	if unclesSha != header.UncleHash {
		err = fmt.Errorf("invalid uncles root hash. received=%x calculated=%x", header.UncleHash, unclesSha)
		return
	}

	// Verify uncles
	if err = sm.VerifyUncles(state, block, parent); err != nil {
		return
	}
	// Accumulate static rewards; block reward, uncle's and uncle inclusion.
	AccumulateRewards(state, block)

	// Commit state objects/accounts to a temporary trie (does not save)
	// used to calculate the state root.
	state.Update()
	if header.Root != state.Root() {
		err = fmt.Errorf("invalid merkle root. received=%x got=%x", header.Root, state.Root())
		return
	}

	// Calculate the td for this block
	//td = CalculateTD(block, parent)
	// Sync the current block's state to the database
	state.Sync()

	// Remove transactions from the pool
	sm.txpool.RemoveTransactions(block.Transactions())

	// This puts transactions in a extra db for rpc
	for i, tx := range block.Transactions() {
		putTx(sm.extraDb, tx, block, uint64(i))
	}

	return state.Logs(), nil
}

// Deliver injects a block body retrieval response into the download queue.
func (q *queue) Deliver(id string, txLists [][]*types.Transaction, uncleLists [][]*types.Header) error {
	q.lock.Lock()
	defer q.lock.Unlock()

	// Short circuit if the block bodies were never requested
	request := q.pendPool[id]
	if request == nil {
		return errNoFetchesPending
	}
	bodyReqTimer.UpdateSince(request.Time)
	delete(q.pendPool, id)

	// If no block bodies were retrieved, mark them as unavailable for the origin peer
	if len(txLists) == 0 || len(uncleLists) == 0 {
		for hash, _ := range request.Headers {
			request.Peer.ignored.Add(hash)
		}
	}
	// Assemble each of the block bodies with their headers and queue for processing
	errs := make([]error, 0)
	for i, header := range request.Headers {
		// Short circuit block assembly if no more bodies are found
		if i >= len(txLists) || i >= len(uncleLists) {
			break
		}
		// Reconstruct the next block if contents match up
		if types.DeriveSha(types.Transactions(txLists[i])) != header.TxHash || types.CalcUncleHash(uncleLists[i]) != header.UncleHash {
			errs = []error{errInvalidBody}
			break
		}
		block := types.NewBlockWithHeader(header).WithBody(txLists[i], uncleLists[i])

		// Queue the block up for processing
		if err := q.enqueue(id, block); err != nil {
			errs = []error{err}
			break
		}
		request.Headers[i] = nil
		delete(q.headerPool, header.Hash())
	}
	// Return all failed or missing fetches to the queue
	for _, header := range request.Headers {
		if header != nil {
			q.headerQueue.Push(header, -float32(header.Number.Uint64()))
		}
	}
	// If none of the blocks were good, it's a stale delivery
	switch {
	case len(errs) == 0:
		return nil

	case len(errs) == 1 && errs[0] == errInvalidBody:
		return errInvalidBody

	case len(errs) == 1 && errs[0] == errInvalidChain:
		return errInvalidChain

	case len(errs) == len(request.Headers):
		return errStaleDelivery

	default:
		return fmt.Errorf("multiple failures: %v", errs)
	}
}