status-go/services/wallet/downloader.go

319 lines
9.0 KiB
Go

package wallet
import (
"context"
"encoding/binary"
"errors"
"math/big"
"time"
"github.com/ethereum/go-ethereum"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/ethclient"
"github.com/ethereum/go-ethereum/log"
)
// TransferType type of the asset that was transferred.
type TransferType string
const (
ethTransfer TransferType = "eth"
erc20Transfer TransferType = "erc20"
erc20TransferEventSignature = "Transfer(address,address,uint256)"
)
var (
zero = big.NewInt(0)
one = big.NewInt(1)
two = big.NewInt(2)
)
// Transfer stores information about transfer.
type Transfer struct {
Type TransferType `json:"type"`
ID common.Hash `json:"-"`
Address common.Address `json:"address"`
BlockNumber *big.Int `json:"blockNumber"`
BlockHash common.Hash `json:"blockhash"`
Timestamp uint64 `json:"timestamp"`
Transaction *types.Transaction `json:"transaction"`
// From is derived from tx signature in order to offload this computation from UI component.
From common.Address `json:"from"`
Receipt *types.Receipt `json:"receipt"`
// Log that was used to generate erc20 transfer. Nil for eth transfer.
Log *types.Log `json:"log"`
}
// ETHTransferDownloader downloads regular eth transfers.
type ETHTransferDownloader struct {
client *ethclient.Client
accounts []common.Address
signer types.Signer
}
// GetTransfers checks if the balance was changed between two blocks.
// If so it downloads transaction that transfer ethereum from that block.
func (d *ETHTransferDownloader) GetTransfers(ctx context.Context, header *DBHeader) (rst []Transfer, err error) {
// TODO(dshulyak) consider caching balance and reset it on reorg
num := new(big.Int).Sub(header.Number, one)
changed := []common.Address{}
for _, address := range d.accounts {
balance, err := d.client.BalanceAt(ctx, address, num)
if err != nil {
return nil, err
}
current, err := d.client.BalanceAt(ctx, address, header.Number)
if err != nil {
return nil, err
}
if current.Cmp(balance) != 0 {
changed = append(changed, address)
}
}
if len(changed) == 0 {
return nil, nil
}
blk, err := d.client.BlockByHash(ctx, header.Hash)
if err != nil {
return nil, err
}
rst, err = d.getTransfersInBlock(ctx, blk, changed)
if err != nil {
return nil, err
}
return rst, nil
}
func (d *ETHTransferDownloader) GetTransfersByNumber(ctx context.Context, number *big.Int) ([]Transfer, error) {
blk, err := d.client.BlockByNumber(ctx, number)
if err != nil {
return nil, err
}
rst, err := d.getTransfersInBlock(ctx, blk, d.accounts)
if err != nil {
return nil, err
}
return rst, err
}
func (d *ETHTransferDownloader) getTransfersInBlock(ctx context.Context, blk *types.Block, accounts []common.Address) (rst []Transfer, err error) {
for _, tx := range blk.Transactions() {
for _, address := range accounts {
from, err := types.Sender(d.signer, tx)
if err != nil {
return nil, err
}
if from == address || (tx.To() != nil && *tx.To() == address) {
receipt, err := d.client.TransactionReceipt(ctx, tx.Hash())
if err != nil {
return nil, err
}
if isTokenTransfer(receipt.Logs) {
log.Debug("eth downloader found token transfer", "hash", tx.Hash())
continue
}
rst = append(rst, Transfer{
Type: ethTransfer,
ID: tx.Hash(),
Address: address,
BlockNumber: blk.Number(),
BlockHash: blk.Hash(),
Timestamp: blk.Time(),
Transaction: tx,
From: from,
Receipt: receipt})
}
}
}
// TODO(dshulyak) test that balance difference was covered by transactions
return rst, nil
}
// NewERC20TransfersDownloader returns new instance.
func NewERC20TransfersDownloader(client *ethclient.Client, accounts []common.Address, signer types.Signer) *ERC20TransfersDownloader {
signature := crypto.Keccak256Hash([]byte(erc20TransferEventSignature))
return &ERC20TransfersDownloader{
client: client,
accounts: accounts,
signature: signature,
signer: signer,
}
}
// ERC20TransfersDownloader is a downloader for erc20 tokens transfers.
type ERC20TransfersDownloader struct {
client *ethclient.Client
accounts []common.Address
// hash of the Transfer event signature
signature common.Hash
// signer is used to derive tx sender from tx signature
signer types.Signer
}
func (d *ERC20TransfersDownloader) paddedAddress(address common.Address) common.Hash {
rst := common.Hash{}
copy(rst[12:], address[:])
return rst
}
func (d *ERC20TransfersDownloader) inboundTopics(address common.Address) [][]common.Hash {
return [][]common.Hash{{d.signature}, {}, {d.paddedAddress(address)}}
}
func (d *ERC20TransfersDownloader) outboundTopics(address common.Address) [][]common.Hash {
return [][]common.Hash{{d.signature}, {d.paddedAddress(address)}, {}}
}
func (d *ERC20TransfersDownloader) transferFromLog(parent context.Context, ethlog types.Log, address common.Address) (Transfer, error) {
ctx, cancel := context.WithTimeout(parent, 3*time.Second)
tx, _, err := d.client.TransactionByHash(ctx, ethlog.TxHash)
cancel()
if err != nil {
return Transfer{}, err
}
from, err := types.Sender(d.signer, tx)
if err != nil {
return Transfer{}, err
}
ctx, cancel = context.WithTimeout(parent, 3*time.Second)
receipt, err := d.client.TransactionReceipt(ctx, ethlog.TxHash)
cancel()
if err != nil {
return Transfer{}, err
}
ctx, cancel = context.WithTimeout(parent, 3*time.Second)
blk, err := d.client.BlockByHash(ctx, ethlog.BlockHash)
cancel()
if err != nil {
return Transfer{}, err
}
index := [4]byte{}
binary.BigEndian.PutUint32(index[:], uint32(ethlog.Index))
id := crypto.Keccak256Hash(ethlog.TxHash.Bytes(), index[:])
return Transfer{
Address: address,
ID: id,
Type: erc20Transfer,
BlockNumber: new(big.Int).SetUint64(ethlog.BlockNumber),
BlockHash: ethlog.BlockHash,
Transaction: tx,
From: from,
Receipt: receipt,
Timestamp: blk.Time(),
Log: &ethlog,
}, nil
}
func (d *ERC20TransfersDownloader) transfersFromLogs(parent context.Context, logs []types.Log, address common.Address) ([]Transfer, error) {
concurrent := NewConcurrentDownloader(parent)
for i := range logs {
l := logs[i]
if l.Removed {
continue
}
concurrent.Add(func(ctx context.Context) error {
transfer, err := d.transferFromLog(ctx, l, address)
if err != nil {
return err
}
concurrent.Push(transfer)
return nil
})
}
select {
case <-concurrent.WaitAsync():
case <-parent.Done():
return nil, errors.New("logs downloader stuck")
}
return concurrent.Get(), concurrent.Error()
}
// GetTransfers for erc20 uses eth_getLogs rpc with Transfer event signature and our address acount.
func (d *ERC20TransfersDownloader) GetTransfers(ctx context.Context, header *DBHeader) ([]Transfer, error) {
hash := header.Hash
transfers := []Transfer{}
for _, address := range d.accounts {
outbound, err := d.client.FilterLogs(ctx, ethereum.FilterQuery{
BlockHash: &hash,
Topics: d.outboundTopics(address),
})
if err != nil {
return nil, err
}
inbound, err := d.client.FilterLogs(ctx, ethereum.FilterQuery{
BlockHash: &hash,
Topics: d.inboundTopics(address),
})
if err != nil {
return nil, err
}
logs := append(outbound, inbound...)
if len(logs) == 0 {
continue
}
rst, err := d.transfersFromLogs(ctx, logs, address)
if err != nil {
return nil, err
}
transfers = append(transfers, rst...)
}
return transfers, nil
}
// GetTransfersInRange returns transfers between two blocks.
// time to get logs for 100000 blocks = 1.144686979s. with 249 events in the result set.
func (d *ERC20TransfersDownloader) GetTransfersInRange(parent context.Context, from, to *big.Int) ([]Transfer, error) {
start := time.Now()
log.Debug("get erc20 transfers in range", "from", from, "to", to)
transfers := []Transfer{}
for _, address := range d.accounts {
ctx, cancel := context.WithTimeout(parent, 5*time.Second)
outbound, err := d.client.FilterLogs(ctx, ethereum.FilterQuery{
FromBlock: from,
ToBlock: to,
Topics: d.outboundTopics(address),
})
cancel()
if err != nil {
return nil, err
}
ctx, cancel = context.WithTimeout(parent, 5*time.Second)
inbound, err := d.client.FilterLogs(ctx, ethereum.FilterQuery{
FromBlock: from,
ToBlock: to,
Topics: d.inboundTopics(address),
})
cancel()
if err != nil {
return nil, err
}
logs := append(outbound, inbound...)
if len(logs) == 0 {
continue
}
rst, err := d.transfersFromLogs(parent, logs, address)
if err != nil {
return nil, err
}
transfers = append(transfers, rst...)
}
log.Debug("found erc20 transfers between two blocks", "from", from, "to", to, "lth", len(transfers), "took", time.Since(start))
return transfers, nil
}
func isTokenTransfer(logs []*types.Log) bool {
signature := crypto.Keccak256Hash([]byte(erc20TransferEventSignature))
for _, l := range logs {
if len(l.Topics) > 0 && l.Topics[0] == signature {
return true
}
}
return false
}