services/wallet/transfer/concurrent.go
package transfer
import (
"context"
"math/big"
"sort"
"sync"
"time"
"github.com/pkg/errors"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/log"
"github.com/status-im/status-go/services/wallet/async"
"github.com/status-im/status-go/services/wallet/balance"
)
const (
NoThreadLimit uint32 = 0
SequentialThreadLimit uint32 = 10
)
// NewConcurrentDownloader creates ConcurrentDownloader instance.
func NewConcurrentDownloader(ctx context.Context, limit uint32) *ConcurrentDownloader {
runner := async.NewQueuedAtomicGroup(ctx, limit)
result := &Result{}
return &ConcurrentDownloader{runner, result}
}
type ConcurrentDownloader struct {
*async.QueuedAtomicGroup
*Result
}
type Result struct {
mu sync.Mutex
transfers []Transfer
headers []*DBHeader
blockRanges [][]*big.Int
}
var errDownloaderStuck = errors.New("eth downloader is stuck")
func (r *Result) Push(transfers ...Transfer) {
r.mu.Lock()
defer r.mu.Unlock()
r.transfers = append(r.transfers, transfers...)
}
func (r *Result) Get() []Transfer {
r.mu.Lock()
defer r.mu.Unlock()
rst := make([]Transfer, len(r.transfers))
copy(rst, r.transfers)
return rst
}
func (r *Result) PushHeader(block *DBHeader) {
r.mu.Lock()
defer r.mu.Unlock()
r.headers = append(r.headers, block)
}
func (r *Result) GetHeaders() []*DBHeader {
r.mu.Lock()
defer r.mu.Unlock()
rst := make([]*DBHeader, len(r.headers))
copy(rst, r.headers)
return rst
}
func (r *Result) PushRange(blockRange []*big.Int) {
r.mu.Lock()
defer r.mu.Unlock()
r.blockRanges = append(r.blockRanges, blockRange)
}
func (r *Result) GetRanges() [][]*big.Int {
r.mu.Lock()
defer r.mu.Unlock()
rst := make([][]*big.Int, len(r.blockRanges))
copy(rst, r.blockRanges)
r.blockRanges = [][]*big.Int{}
return rst
}
// Downloader downloads transfers from single block using number.
type Downloader interface {
GetTransfersByNumber(context.Context, *big.Int) ([]Transfer, error)
}
// Returns new block ranges that contain transfers and found block headers that contain transfers, and a block where
// beginning of trasfers history detected
func checkRangesWithStartBlock(parent context.Context, client balance.Reader, cache balance.Cacher,
account common.Address, ranges [][]*big.Int, threadLimit uint32, startBlock *big.Int) (
resRanges [][]*big.Int, headers []*DBHeader, newStartBlock *big.Int, err error) {
log.Debug("start checkRanges", "account", account.Hex(), "ranges len", len(ranges), "startBlock", startBlock)
ctx, cancel := context.WithTimeout(parent, 30*time.Second)
defer cancel()
c := NewConcurrentDownloader(ctx, threadLimit)
newStartBlock = startBlock
for _, blocksRange := range ranges {
from := blocksRange[0]
to := blocksRange[1]
log.Debug("check block range", "from", from, "to", to)
if startBlock != nil {
if to.Cmp(newStartBlock) <= 0 {
log.Debug("'to' block is less than 'start' block", "to", to, "startBlock", startBlock)
continue
}
}
c.Add(func(ctx context.Context) error {
if from.Cmp(to) >= 0 {
log.Debug("'from' block is greater than or equal to 'to' block", "from", from, "to", to)
return nil
}
log.Debug("eth transfers comparing blocks", "from", from, "to", to)
if startBlock != nil {
if to.Cmp(startBlock) <= 0 {
log.Debug("'to' block is less than 'start' block", "to", to, "startBlock", startBlock)
return nil
}
}
lb, err := cache.BalanceAt(ctx, client, account, from)
if err != nil {
return err
}
hb, err := cache.BalanceAt(ctx, client, account, to)
if err != nil {
return err
}
if lb.Cmp(hb) == 0 {
log.Debug("balances are equal", "from", from, "to", to, "lb", lb, "hb", hb)
hn, err := cache.NonceAt(ctx, client, account, to)
if err != nil {
return err
}
// if nonce is zero in a newer block then there is no need to check an older one
if *hn == 0 {
log.Debug("zero nonce", "to", to)
if hb.Cmp(big.NewInt(0)) == 0 { // balance is 0, nonce is 0, we stop checking further, that will be the start block (even though the real one can be a later one)
if startBlock != nil {
if to.Cmp(newStartBlock) > 0 {
log.Debug("found possible start block, we should not search back", "block", to)
newStartBlock = to // increase newStartBlock if we found a new higher block
}
} else {
newStartBlock = to
}
}
return nil
}
ln, err := cache.NonceAt(ctx, client, account, from)
if err != nil {
return err
}
if *ln == *hn {
log.Debug("transaction count is also equal", "from", from, "to", to, "ln", *ln, "hn", *hn)
return nil
}
}
if new(big.Int).Sub(to, from).Cmp(one) == 0 {
// WARNING: Block hash calculation from plain header returns a wrong value.
header, err := client.HeaderByNumber(ctx, to)
if err != nil {
return err
}
// Obtain block hash from first transaction
blockHash, err := client.CallBlockHashByTransaction(ctx, to, 0)
if err != nil {
return err
}
c.PushHeader(toDBHeader(header, blockHash, account))
return nil
}
mid := new(big.Int).Add(from, to)
mid = mid.Div(mid, two)
_, err = cache.BalanceAt(ctx, client, account, mid)
if err != nil {
return err
}
log.Debug("balances are not equal", "from", from, "mid", mid, "to", to)
c.PushRange([]*big.Int{mid, to})
c.PushRange([]*big.Int{from, mid})
return nil
})
}
select {
case <-c.WaitAsync():
case <-ctx.Done():
return nil, nil, nil, errDownloaderStuck
}
if c.Error() != nil {
return nil, nil, nil, errors.Wrap(c.Error(), "failed to dowload transfers using concurrent downloader")
}
log.Debug("end checkRanges", "account", account.Hex(), "newStartBlock", newStartBlock)
return c.GetRanges(), c.GetHeaders(), newStartBlock, nil
}
func findBlocksWithEthTransfers(parent context.Context, client balance.Reader, cache balance.Cacher,
account common.Address, low, high *big.Int, noLimit bool, threadLimit uint32) (
from *big.Int, headers []*DBHeader, resStartBlock *big.Int, err error) {
ranges := [][]*big.Int{{low, high}}
from = big.NewInt(low.Int64())
headers = []*DBHeader{}
var lvl = 1
for len(ranges) > 0 && lvl <= 30 {
log.Debug("check blocks ranges", "lvl", lvl, "ranges len", len(ranges))
lvl++
// Check if there are transfers in blocks in ranges. To do that, nonce and balance is checked
// the block ranges that have transfers are returned
newRanges, newHeaders, strtBlock, err := checkRangesWithStartBlock(parent, client, cache,
account, ranges, threadLimit, resStartBlock)
resStartBlock = strtBlock
if err != nil {
return nil, nil, nil, err
}
headers = append(headers, newHeaders...)
if len(newRanges) > 0 {
log.Debug("found new ranges", "account", account, "lvl", lvl, "new ranges len", len(newRanges))
}
if len(newRanges) > 60 && !noLimit {
sort.SliceStable(newRanges, func(i, j int) bool {
return newRanges[i][0].Cmp(newRanges[j][0]) == 1
})
newRanges = newRanges[:60]
from = newRanges[len(newRanges)-1][0]
}
ranges = newRanges
}
return
}