status-go/services/wallet/transfer/iterative.go

85 lines
2.3 KiB
Go

package transfer
import (
"context"
"errors"
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/log"
)
// SetupIterativeDownloader configures IterativeDownloader with last known synced block.
func SetupIterativeDownloader(
client HeaderReader, address common.Address,
downloader BatchDownloader, size *big.Int, to *big.Int, from *big.Int) (*IterativeDownloader, error) {
if to == nil || from == nil {
return nil, errors.New("to or from cannot be nil")
}
log.Debug("iterative downloader", "address", address, "from", from, "to", to, "size", size)
d := &IterativeDownloader{
client: client,
batchSize: size,
downloader: downloader,
from: from,
to: to,
}
return d, nil
}
// BatchDownloader interface for loading transfers in batches in speificed range of blocks.
type BatchDownloader interface {
GetHeadersInRange(ctx context.Context, from, to *big.Int) ([]*DBHeader, error)
}
// IterativeDownloader downloads batches of transfers in a specified size.
type IterativeDownloader struct {
client HeaderReader
batchSize *big.Int
downloader BatchDownloader
from, to *big.Int
previous *big.Int
}
// Finished true when earliest block with given sync option is zero.
func (d *IterativeDownloader) Finished() bool {
return d.from.Cmp(d.to) == 0
}
// Header return last synced header.
func (d *IterativeDownloader) Header() *big.Int {
return d.previous
}
// Next moves closer to the end on every new iteration.
func (d *IterativeDownloader) Next(parent context.Context) ([]*DBHeader, *big.Int, *big.Int, error) {
to := d.to
from := new(big.Int).Sub(to, d.batchSize)
// if start < 0; start = 0
if from.Cmp(d.from) == -1 {
from = d.from
}
headers, err := d.downloader.GetHeadersInRange(parent, from, to)
log.Debug("load erc20 transfers in range", "from", from, "to", to, "batchSize", d.batchSize)
if err != nil {
log.Error("failed to get transfer in between two blocks", "from", from, "to", to, "error", err)
return nil, nil, nil, err
}
d.previous, d.to = d.to, from
return headers, d.from, to, nil
}
// Revert reverts last step progress. Should be used if application failed to process transfers.
// For example failed to persist them.
func (d *IterativeDownloader) Revert() {
if d.previous != nil {
d.from = d.previous
}
}