93 lines
2.6 KiB
Go
93 lines
2.6 KiB
Go
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package wallet
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import (
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"context"
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"math/big"
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"time"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/log"
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)
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// SetupIterativeDownloader configures IterativeDownloader with last known synced block.
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func SetupIterativeDownloader(
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db *Database, client HeaderReader, address common.Address, option SyncOption,
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downloader BatchDownloader, size *big.Int, to *DBHeader) (*IterativeDownloader, error) {
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from, err := db.GetLatestSynced(address, option)
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if err != nil {
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log.Error("failed to get latest synced block", "error", err)
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return nil, err
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}
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if from == nil {
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from = &DBHeader{Number: zero}
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}
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log.Debug("iterative downloader", "address", address, "from", from.Number, "to", to.Number)
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d := &IterativeDownloader{
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client: client,
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batchSize: size,
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downloader: downloader,
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from: from,
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to: to,
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}
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return d, nil
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}
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// BatchDownloader interface for loading transfers in batches in speificed range of blocks.
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type BatchDownloader interface {
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GetTransfersInRange(ctx context.Context, from, to *big.Int) ([]Transfer, error)
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}
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// IterativeDownloader downloads batches of transfers in a specified size.
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type IterativeDownloader struct {
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client HeaderReader
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batchSize *big.Int
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downloader BatchDownloader
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from, to *DBHeader
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previous *DBHeader
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}
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// Finished true when earliest block with given sync option is zero.
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func (d *IterativeDownloader) Finished() bool {
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return d.from.Number.Cmp(d.to.Number) == 0
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}
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// Header return last synced header.
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func (d *IterativeDownloader) Header() *DBHeader {
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return d.previous
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}
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// Next moves closer to the end on every new iteration.
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func (d *IterativeDownloader) Next(parent context.Context) ([]Transfer, error) {
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to := new(big.Int).Add(d.from.Number, d.batchSize)
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// if start < 0; start = 0
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if to.Cmp(d.to.Number) == 1 {
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to = d.to.Number
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}
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transfers, err := d.downloader.GetTransfersInRange(parent, d.from.Number, to)
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if err != nil {
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log.Error("failed to get transfer in between two bloks", "from", d.from.Number, "to", to, "error", err)
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return nil, err
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}
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// use integers instead of DBHeader
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ctx, cancel := context.WithTimeout(parent, 5*time.Second)
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header, err := d.client.HeaderByNumber(ctx, to)
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cancel()
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if err != nil {
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log.Error("failed to get header by number", "from", d.from.Number, "to", to, "error", err)
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return nil, err
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}
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d.previous, d.from = d.from, toDBHeader(header)
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return transfers, nil
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}
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// Revert reverts last step progress. Should be used if application failed to process transfers.
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// For example failed to persist them.
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func (d *IterativeDownloader) Revert() {
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if d.previous != nil {
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d.from = d.previous
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}
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}
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