github.com/neatlab/neatio@v1.7.3-0.20220425043230-d903e92fcc75/neatptc/downloader/queue.go

package downloader

import (
	"errors"
	"fmt"
	"sync"
	"time"

	"github.com/neatlab/neatio/chain/core/types"
	"github.com/neatlab/neatio/chain/log"
	"github.com/neatlab/neatio/utilities/common"
	"github.com/neatlab/neatio/utilities/common/prque"
	"github.com/neatlab/neatio/utilities/metrics"
)

var (
	blockCacheItems      = 8192
	blockCacheMemory     = 64 * 1024 * 1024
	blockCacheSizeWeight = 0.1
)

var (
	errNoFetchesPending = errors.New("no fetches pending")
	errStaleDelivery    = errors.New("stale delivery")
)

type fetchRequest struct {
	Peer    *peerConnection
	From    uint64
	Headers []*types.Header
	Time    time.Time
}

type fetchResult struct {
	Pending int
	Hash    common.Hash

	Header       *types.Header
	Uncles       []*types.Header
	Transactions types.Transactions
	Receipts     types.Receipts
}

type queue struct {
	mode SyncMode

	headerHead      common.Hash
	headerTaskPool  map[uint64]*types.Header
	headerTaskQueue *prque.Prque
	headerPeerMiss  map[string]map[uint64]struct{}
	headerPendPool  map[string]*fetchRequest
	headerResults   []*types.Header
	headerProced    int
	headerOffset    uint64
	headerContCh    chan bool

	blockTaskPool  map[common.Hash]*types.Header
	blockTaskQueue *prque.Prque
	blockPendPool  map[string]*fetchRequest
	blockDonePool  map[common.Hash]struct{}

	receiptTaskPool  map[common.Hash]*types.Header
	receiptTaskQueue *prque.Prque
	receiptPendPool  map[string]*fetchRequest
	receiptDonePool  map[common.Hash]struct{}

	resultCache  []*fetchResult
	resultOffset uint64
	resultSize   common.StorageSize

	lock   *sync.Mutex
	active *sync.Cond
	closed bool
}

func newQueue() *queue {
	lock := new(sync.Mutex)
	return &queue{
		headerPendPool:   make(map[string]*fetchRequest),
		headerContCh:     make(chan bool),
		blockTaskPool:    make(map[common.Hash]*types.Header),
		blockTaskQueue:   prque.New(nil),
		blockPendPool:    make(map[string]*fetchRequest),
		blockDonePool:    make(map[common.Hash]struct{}),
		receiptTaskPool:  make(map[common.Hash]*types.Header),
		receiptTaskQueue: prque.New(nil),
		receiptPendPool:  make(map[string]*fetchRequest),
		receiptDonePool:  make(map[common.Hash]struct{}),
		resultCache:      make([]*fetchResult, blockCacheItems),
		active:           sync.NewCond(lock),
		lock:             lock,
	}
}

func (q *queue) Reset() {
	q.lock.Lock()
	defer q.lock.Unlock()

	q.closed = false
	q.mode = FullSync

	q.headerHead = common.Hash{}
	q.headerPendPool = make(map[string]*fetchRequest)

	q.blockTaskPool = make(map[common.Hash]*types.Header)
	q.blockTaskQueue.Reset()
	q.blockPendPool = make(map[string]*fetchRequest)
	q.blockDonePool = make(map[common.Hash]struct{})

	q.receiptTaskPool = make(map[common.Hash]*types.Header)
	q.receiptTaskQueue.Reset()
	q.receiptPendPool = make(map[string]*fetchRequest)
	q.receiptDonePool = make(map[common.Hash]struct{})

	q.resultCache = make([]*fetchResult, blockCacheItems)
	q.resultOffset = 0
}

func (q *queue) Close() {
	q.lock.Lock()
	q.closed = true
	q.lock.Unlock()
	q.active.Broadcast()
}

func (q *queue) PendingHeaders() int {
	q.lock.Lock()
	defer q.lock.Unlock()

	return q.headerTaskQueue.Size()
}

func (q *queue) PendingBlocks() int {
	q.lock.Lock()
	defer q.lock.Unlock()

	return q.blockTaskQueue.Size()
}

func (q *queue) PendingReceipts() int {
	q.lock.Lock()
	defer q.lock.Unlock()

	return q.receiptTaskQueue.Size()
}

func (q *queue) InFlightHeaders() bool {
	q.lock.Lock()
	defer q.lock.Unlock()

	return len(q.headerPendPool) > 0
}

func (q *queue) InFlightBlocks() bool {
	q.lock.Lock()
	defer q.lock.Unlock()

	return len(q.blockPendPool) > 0
}

func (q *queue) InFlightReceipts() bool {
	q.lock.Lock()
	defer q.lock.Unlock()

	return len(q.receiptPendPool) > 0
}

func (q *queue) Idle() bool {
	q.lock.Lock()
	defer q.lock.Unlock()

	queued := q.blockTaskQueue.Size() + q.receiptTaskQueue.Size()
	pending := len(q.blockPendPool) + len(q.receiptPendPool)
	cached := len(q.blockDonePool) + len(q.receiptDonePool)

	return (queued + pending + cached) == 0
}

func (q *queue) ShouldThrottleBlocks() bool {
	q.lock.Lock()
	defer q.lock.Unlock()

	return q.resultSlots(q.blockPendPool, q.blockDonePool) <= 0
}

func (q *queue) ShouldThrottleReceipts() bool {
	q.lock.Lock()
	defer q.lock.Unlock()

	return q.resultSlots(q.receiptPendPool, q.receiptDonePool) <= 0
}

func (q *queue) resultSlots(pendPool map[string]*fetchRequest, donePool map[common.Hash]struct{}) int {

	limit := len(q.resultCache)
	if common.StorageSize(len(q.resultCache))*q.resultSize > common.StorageSize(blockCacheMemory) {
		limit = int((common.StorageSize(blockCacheMemory) + q.resultSize - 1) / q.resultSize)
	}

	finished := 0
	for _, result := range q.resultCache[:limit] {
		if result == nil {
			break
		}
		if _, ok := donePool[result.Hash]; ok {
			finished++
		}
	}

	pending := 0
	for _, request := range pendPool {
		for _, header := range request.Headers {
			if header.Number.Uint64() < q.resultOffset+uint64(limit) {
				pending++
			}
		}
	}

	return limit - finished - pending
}

func (q *queue) ScheduleSkeleton(from uint64, skeleton []*types.Header) {
	q.lock.Lock()
	defer q.lock.Unlock()

	if q.headerResults != nil {
		panic("skeleton assembly already in progress")
	}

	q.headerTaskPool = make(map[uint64]*types.Header)
	q.headerTaskQueue = prque.New(nil)
	q.headerPeerMiss = make(map[string]map[uint64]struct{})
	q.headerResults = make([]*types.Header, len(skeleton)*MaxHeaderFetch)
	q.headerProced = 0
	q.headerOffset = from
	q.headerContCh = make(chan bool, 1)

	for i, header := range skeleton {
		index := from + uint64(i*MaxHeaderFetch)

		q.headerTaskPool[index] = header
		q.headerTaskQueue.Push(index, -int64(index))
	}
}

func (q *queue) RetrieveHeaders() ([]*types.Header, int) {
	q.lock.Lock()
	defer q.lock.Unlock()

	headers, proced := q.headerResults, q.headerProced
	q.headerResults, q.headerProced = nil, 0

	return headers, proced
}

func (q *queue) Schedule(headers []*types.Header, from uint64) []*types.Header {
	q.lock.Lock()
	defer q.lock.Unlock()

	inserts := make([]*types.Header, 0, len(headers))
	for _, header := range headers {

		hash := header.Hash()
		if header.Number == nil || header.Number.Uint64() != from {
			log.Warn("Header broke chain ordering", "number", header.Number, "hash", hash, "expected", from)
			break
		}
		if q.headerHead != (common.Hash{}) && q.headerHead != header.ParentHash {
			log.Warn("Header broke chain ancestry", "number", header.Number, "hash", hash)
			break
		}

		if _, ok := q.blockTaskPool[hash]; ok {
			log.Warn("Header  already scheduled for block fetch", "number", header.Number, "hash", hash)
			continue
		}
		if _, ok := q.receiptTaskPool[hash]; ok {
			log.Warn("Header already scheduled for receipt fetch", "number", header.Number, "hash", hash)
			continue
		}

		q.blockTaskPool[hash] = header
		q.blockTaskQueue.Push(header, -int64(header.Number.Uint64()))

		if q.mode == FastSync {
			q.receiptTaskPool[hash] = header
			q.receiptTaskQueue.Push(header, -int64(header.Number.Uint64()))
		}
		inserts = append(inserts, header)
		q.headerHead = hash
		from++
	}
	return inserts
}

func (q *queue) Results(block bool) []*fetchResult {
	q.lock.Lock()
	defer q.lock.Unlock()

	nproc := q.countProcessableItems()
	for nproc == 0 && !q.closed {
		if !block {
			return nil
		}
		q.active.Wait()
		nproc = q.countProcessableItems()
	}

	if nproc > maxResultsProcess {
		nproc = maxResultsProcess
	}
	results := make([]*fetchResult, nproc)
	copy(results, q.resultCache[:nproc])
	if len(results) > 0 {

		for _, result := range results {
			hash := result.Header.Hash()
			delete(q.blockDonePool, hash)
			delete(q.receiptDonePool, hash)
		}

		copy(q.resultCache, q.resultCache[nproc:])
		for i := len(q.resultCache) - nproc; i < len(q.resultCache); i++ {
			q.resultCache[i] = nil
		}

		q.resultOffset += uint64(nproc)

		for _, result := range results {
			size := result.Header.Size()
			for _, uncle := range result.Uncles {
				size += uncle.Size()
			}
			for _, receipt := range result.Receipts {
				size += receipt.Size()
			}
			for _, tx := range result.Transactions {
				size += tx.Size()
			}
			q.resultSize = common.StorageSize(blockCacheSizeWeight)*size + (1-common.StorageSize(blockCacheSizeWeight))*q.resultSize
		}
	}
	return results
}

func (q *queue) countProcessableItems() int {
	for i, result := range q.resultCache {
		if result == nil || result.Pending > 0 {
			return i
		}
	}
	return len(q.resultCache)
}

func (q *queue) ReserveHeaders(p *peerConnection, count int) *fetchRequest {
	q.lock.Lock()
	defer q.lock.Unlock()

	if _, ok := q.headerPendPool[p.id]; ok {
		return nil
	}

	send, skip := uint64(0), []uint64{}
	for send == 0 && !q.headerTaskQueue.Empty() {
		from, _ := q.headerTaskQueue.Pop()
		if q.headerPeerMiss[p.id] != nil {
			if _, ok := q.headerPeerMiss[p.id][from.(uint64)]; ok {
				skip = append(skip, from.(uint64))
				continue
			}
		}
		send = from.(uint64)
	}

	for _, from := range skip {
		q.headerTaskQueue.Push(from, -int64(from))
	}

	if send == 0 {
		return nil
	}
	request := &fetchRequest{
		Peer: p,
		From: send,
		Time: time.Now(),
	}
	q.headerPendPool[p.id] = request
	return request
}

func (q *queue) ReserveBodies(p *peerConnection, count int) (*fetchRequest, bool, error) {
	isNoop := func(header *types.Header) bool {
		return header.TxHash == types.EmptyRootHash && header.UncleHash == types.EmptyUncleHash
	}
	q.lock.Lock()
	defer q.lock.Unlock()

	return q.reserveHeaders(p, count, q.blockTaskPool, q.blockTaskQueue, q.blockPendPool, q.blockDonePool, isNoop)
}

func (q *queue) ReserveReceipts(p *peerConnection, count int) (*fetchRequest, bool, error) {
	isNoop := func(header *types.Header) bool {
		return header.ReceiptHash == types.EmptyRootHash
	}
	q.lock.Lock()
	defer q.lock.Unlock()

	return q.reserveHeaders(p, count, q.receiptTaskPool, q.receiptTaskQueue, q.receiptPendPool, q.receiptDonePool, isNoop)
}

func (q *queue) reserveHeaders(p *peerConnection, count int, taskPool map[common.Hash]*types.Header, taskQueue *prque.Prque,
	pendPool map[string]*fetchRequest, donePool map[common.Hash]struct{}, isNoop func(*types.Header) bool) (*fetchRequest, bool, error) {

	if taskQueue.Empty() {
		return nil, false, nil
	}
	if _, ok := pendPool[p.id]; ok {
		return nil, false, nil
	}

	space := q.resultSlots(pendPool, donePool)

	send := make([]*types.Header, 0, count)
	skip := make([]*types.Header, 0)

	progress := false
	for proc := 0; proc < space && len(send) < count && !taskQueue.Empty(); proc++ {
		header := taskQueue.PopItem().(*types.Header)
		hash := header.Hash()

		index := int(header.Number.Int64() - int64(q.resultOffset))
		if index >= len(q.resultCache) || index < 0 {
			common.Report("index allocation went beyond available resultCache space")
			return nil, false, errInvalidChain
		}
		if q.resultCache[index] == nil {
			components := 1
			if q.mode == FastSync {
				components = 2
			}
			q.resultCache[index] = &fetchResult{
				Pending: components,
				Hash:    hash,
				Header:  header,
			}
		}

		if isNoop(header) {
			donePool[hash] = struct{}{}
			delete(taskPool, hash)

			space, proc = space-1, proc-1
			q.resultCache[index].Pending--
			progress = true
			continue
		}

		if p.Lacks(hash) {
			skip = append(skip, header)
		} else {
			send = append(send, header)
		}
	}

	for _, header := range skip {
		taskQueue.Push(header, -int64(header.Number.Uint64()))
	}
	if progress {

		q.active.Signal()
	}

	if len(send) == 0 {
		return nil, progress, nil
	}
	request := &fetchRequest{
		Peer:    p,
		Headers: send,
		Time:    time.Now(),
	}
	pendPool[p.id] = request

	return request, progress, nil
}

func (q *queue) CancelHeaders(request *fetchRequest) {
	q.cancel(request, q.headerTaskQueue, q.headerPendPool)
}

func (q *queue) CancelBodies(request *fetchRequest) {
	q.cancel(request, q.blockTaskQueue, q.blockPendPool)
}

func (q *queue) CancelReceipts(request *fetchRequest) {
	q.cancel(request, q.receiptTaskQueue, q.receiptPendPool)
}

func (q *queue) cancel(request *fetchRequest, taskQueue *prque.Prque, pendPool map[string]*fetchRequest) {
	q.lock.Lock()
	defer q.lock.Unlock()

	if request.From > 0 {
		taskQueue.Push(request.From, -int64(request.From))
	}
	for _, header := range request.Headers {
		taskQueue.Push(header, -int64(header.Number.Uint64()))
	}
	delete(pendPool, request.Peer.id)
}

func (q *queue) Revoke(peerId string) {
	q.lock.Lock()
	defer q.lock.Unlock()

	if request, ok := q.blockPendPool[peerId]; ok {
		for _, header := range request.Headers {
			q.blockTaskQueue.Push(header, -int64(header.Number.Uint64()))
		}
		delete(q.blockPendPool, peerId)
	}
	if request, ok := q.receiptPendPool[peerId]; ok {
		for _, header := range request.Headers {
			q.receiptTaskQueue.Push(header, -int64(header.Number.Uint64()))
		}
		delete(q.receiptPendPool, peerId)
	}
}

func (q *queue) ExpireHeaders(timeout time.Duration) map[string]int {
	q.lock.Lock()
	defer q.lock.Unlock()

	return q.expire(timeout, q.headerPendPool, q.headerTaskQueue, headerTimeoutMeter)
}

func (q *queue) ExpireBodies(timeout time.Duration) map[string]int {
	q.lock.Lock()
	defer q.lock.Unlock()

	return q.expire(timeout, q.blockPendPool, q.blockTaskQueue, bodyTimeoutMeter)
}

func (q *queue) ExpireReceipts(timeout time.Duration) map[string]int {
	q.lock.Lock()
	defer q.lock.Unlock()

	return q.expire(timeout, q.receiptPendPool, q.receiptTaskQueue, receiptTimeoutMeter)
}

func (q *queue) expire(timeout time.Duration, pendPool map[string]*fetchRequest, taskQueue *prque.Prque, timeoutMeter metrics.Meter) map[string]int {

	expiries := make(map[string]int)
	for id, request := range pendPool {
		if time.Since(request.Time) > timeout {

			timeoutMeter.Mark(1)

			if request.From > 0 {
				taskQueue.Push(request.From, -int64(request.From))
			}
			for _, header := range request.Headers {
				taskQueue.Push(header, -int64(header.Number.Uint64()))
			}

			expiries[id] = len(request.Headers)
		}
	}

	for id := range expiries {
		delete(pendPool, id)
	}
	return expiries
}

func (q *queue) DeliverHeaders(id string, headers []*types.Header, headerProcCh chan []*types.Header) (int, error) {
	q.lock.Lock()
	defer q.lock.Unlock()

	request := q.headerPendPool[id]
	if request == nil {
		return 0, errNoFetchesPending
	}
	headerReqTimer.UpdateSince(request.Time)
	delete(q.headerPendPool, id)

	target := q.headerTaskPool[request.From].Hash()

	accepted := len(headers) == MaxHeaderFetch
	if accepted {
		if headers[0].Number.Uint64() != request.From {
			log.Trace("First header broke chain ordering", "peer", id, "number", headers[0].Number, "hash", headers[0].Hash(), request.From)
			accepted = false
		} else if headers[len(headers)-1].Hash() != target {
			log.Trace("Last header broke skeleton structure ", "peer", id, "number", headers[len(headers)-1].Number, "hash", headers[len(headers)-1].Hash(), "expected", target)
			accepted = false
		}
	}
	if accepted {
		for i, header := range headers[1:] {
			hash := header.Hash()
			if want := request.From + 1 + uint64(i); header.Number.Uint64() != want {
				log.Warn("Header broke chain ordering", "peer", id, "number", header.Number, "hash", hash, "expected", want)
				accepted = false
				break
			}
			if headers[i].Hash() != header.ParentHash {
				log.Warn("Header broke chain ancestry", "peer", id, "number", header.Number, "hash", hash)
				accepted = false
				break
			}
		}
	}

	if !accepted {
		log.Trace("Skeleton filling not accepted", "peer", id, "from", request.From)

		miss := q.headerPeerMiss[id]
		if miss == nil {
			q.headerPeerMiss[id] = make(map[uint64]struct{})
			miss = q.headerPeerMiss[id]
		}
		miss[request.From] = struct{}{}

		q.headerTaskQueue.Push(request.From, -int64(request.From))
		return 0, errors.New("delivery not accepted")
	}

	copy(q.headerResults[request.From-q.headerOffset:], headers)
	delete(q.headerTaskPool, request.From)

	ready := 0
	for q.headerProced+ready < len(q.headerResults) && q.headerResults[q.headerProced+ready] != nil {
		ready += MaxHeaderFetch
	}
	if ready > 0 {

		process := make([]*types.Header, ready)
		copy(process, q.headerResults[q.headerProced:q.headerProced+ready])

		select {
		case headerProcCh <- process:
			log.Trace("Pre-scheduled new headers", "peer", id, "count", len(process), "from", process[0].Number)
			q.headerProced += len(process)
		default:
		}
	}

	if len(q.headerTaskPool) == 0 {
		q.headerContCh <- false
	}
	return len(headers), nil
}

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)
}

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)
}

func (q *queue) deliver(id string, taskPool map[common.Hash]*types.Header, taskQueue *prque.Prque,
	pendPool map[string]*fetchRequest, donePool map[common.Hash]struct{}, reqTimer metrics.Timer,
	results int, reconstruct func(header *types.Header, index int, result *fetchResult) error) (int, error) {

	request := pendPool[id]
	if request == nil {
		return 0, errNoFetchesPending
	}
	reqTimer.UpdateSince(request.Time)
	delete(pendPool, id)

	if results == 0 {
		for _, header := range request.Headers {
			request.Peer.MarkLacking(header.Hash())
		}
	}

	var (
		accepted int
		failure  error
		useful   bool
	)
	for i, header := range request.Headers {

		if i >= results {
			break
		}

		index := int(header.Number.Int64() - int64(q.resultOffset))
		if index >= len(q.resultCache) || index < 0 || q.resultCache[index] == nil {
			failure = errInvalidChain
			break
		}
		if err := reconstruct(header, i, q.resultCache[index]); err != nil {
			failure = err
			break
		}
		hash := header.Hash()

		donePool[hash] = struct{}{}
		q.resultCache[index].Pending--
		useful = true
		accepted++

		request.Headers[i] = nil
		delete(taskPool, hash)
	}

	for _, header := range request.Headers {
		if header != nil {
			taskQueue.Push(header, -int64(header.Number.Uint64()))
		}
	}

	if accepted > 0 {
		q.active.Signal()
	}

	switch {
	case failure == nil || failure == errInvalidChain:
		return accepted, failure
	case useful:
		return accepted, fmt.Errorf("partial failure: %v", failure)
	default:
		return accepted, errStaleDelivery
	}
}

func (q *queue) Prepare(offset uint64, mode SyncMode) {
	q.lock.Lock()
	defer q.lock.Unlock()

	if q.resultOffset < offset {
		q.resultOffset = offset
	}
	q.mode = mode
}