// Copyright 2019 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package snapshot
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"io"
"time"
"github.com/VictoriaMetrics/fastcache"
"github.com/ava-labs/coreth/core/rawdb"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/trie"
)
// journalGenerator is a disk layer entry containing the generator progress marker.
type journalGenerator struct {
Wiping bool // Whether the database was in progress of being wiped
Done bool // Whether the generator finished creating the snapshot
Marker []byte
Accounts uint64
Slots uint64
Storage uint64
}
// journalDestruct is an account deletion entry in a diffLayer's disk journal.
type journalDestruct struct {
Hash common.Hash
}
// journalAccount is an account entry in a diffLayer's disk journal.
type journalAccount struct {
Hash common.Hash
Blob []byte
}
// journalStorage is an account's storage map in a diffLayer's disk journal.
type journalStorage struct {
Hash common.Hash
Keys []common.Hash
Vals [][]byte
}
// loadSnapshot loads a pre-existing state snapshot backed by a key-value store.
func loadSnapshot(diskdb ethdb.KeyValueStore, triedb *trie.Database, cache int, root common.Hash) (snapshot, error) {
// Retrieve the block number and hash of the snapshot, failing if no snapshot
// is present in the database (or crashed mid-update).
baseRoot := rawdb.ReadSnapshotRoot(diskdb)
if baseRoot == (common.Hash{}) {
return nil, errors.New("missing or corrupted snapshot")
}
base := &diskLayer{
diskdb: diskdb,
triedb: triedb,
cache: fastcache.New(cache * 1024 * 1024),
root: baseRoot,
}
// Retrieve the journal, it must exist since even for 0 layer it stores whether
// we've already generated the snapshot or are in progress only
journal := rawdb.ReadSnapshotJournal(diskdb)
if len(journal) == 0 {
return nil, errors.New("missing or corrupted snapshot journal")
}
r := rlp.NewStream(bytes.NewReader(journal), 0)
// Read the snapshot generation progress for the disk layer
var generator journalGenerator
if err := r.Decode(&generator); err != nil {
return nil, fmt.Errorf("failed to load snapshot progress marker: %v", err)
}
// Load all the snapshot diffs from the journal
snapshot, err := loadDiffLayer(base, r)
if err != nil {
return nil, err
}
// Entire snapshot journal loaded, sanity check the head and return
// Journal doesn't exist, don't worry if it's not supposed to
if head := snapshot.Root(); head != root {
return nil, fmt.Errorf("head doesn't match snapshot: have %#x, want %#x", head, root)
}
// Everything loaded correctly, resume any suspended operations
if !generator.Done {
// If the generator was still wiping, restart one from scratch (fine for
// now as it's rare and the wiper deletes the stuff it touches anyway, so
// restarting won't incur a lot of extra database hops.
var wiper chan struct{}
if generator.Wiping {
log.Info("Resuming previous snapshot wipe")
wiper = wipeSnapshot(diskdb, false)
}
// Whether or not wiping was in progress, load any generator progress too
base.genMarker = generator.Marker
if base.genMarker == nil {
base.genMarker = []byte{}
}
base.genPending = make(chan struct{})
base.genAbort = make(chan chan *generatorStats)
var origin uint64
if len(generator.Marker) >= 8 {
origin = binary.BigEndian.Uint64(generator.Marker)
}
go base.generate(&generatorStats{
wiping: wiper,
origin: origin,
start: time.Now(),
accounts: generator.Accounts,
slots: generator.Slots,
storage: common.StorageSize(generator.Storage),
})
}
return snapshot, nil
}
// loadDiffLayer reads the next sections of a snapshot journal, reconstructing a new
// diff and verifying that it can be linked to the requested parent.
func loadDiffLayer(parent snapshot, r *rlp.Stream) (snapshot, error) {
// Read the next diff journal entry
var root common.Hash
if err := r.Decode(&root); err != nil {
// The first read may fail with EOF, marking the end of the journal
if err == io.EOF {
return parent, nil
}
return nil, fmt.Errorf("load diff root: %v", err)
}
var destructs []journalDestruct
if err := r.Decode(&destructs); err != nil {
return nil, fmt.Errorf("load diff destructs: %v", err)
}
destructSet := make(map[common.Hash]struct{})
for _, entry := range destructs {
destructSet[entry.Hash] = struct{}{}
}
var accounts []journalAccount
if err := r.Decode(&accounts); err != nil {
return nil, fmt.Errorf("load diff accounts: %v", err)
}
accountData := make(map[common.Hash][]byte)
for _, entry := range accounts {
if len(entry.Blob) > 0 { // RLP loses nil-ness, but `[]byte{}` is not a valid item, so reinterpret that
accountData[entry.Hash] = entry.Blob
} else {
accountData[entry.Hash] = nil
}
}
var storage []journalStorage
if err := r.Decode(&storage); err != nil {
return nil, fmt.Errorf("load diff storage: %v", err)
}
storageData := make(map[common.Hash]map[common.Hash][]byte)
for _, entry := range storage {
slots := make(map[common.Hash][]byte)
for i, key := range entry.Keys {
if len(entry.Vals[i]) > 0 { // RLP loses nil-ness, but `[]byte{}` is not a valid item, so reinterpret that
slots[key] = entry.Vals[i]
} else {
slots[key] = nil
}
}
storageData[entry.Hash] = slots
}
return loadDiffLayer(newDiffLayer(parent, root, destructSet, accountData, storageData), r)
}
// Journal writes the persistent layer generator stats into a buffer to be stored
// in the database as the snapshot journal.
func (dl *diskLayer) Journal(buffer *bytes.Buffer) (common.Hash, error) {
// If the snapshot is currently being generated, abort it
var stats *generatorStats
if dl.genAbort != nil {
abort := make(chan *generatorStats)
dl.genAbort <- abort
if stats = <-abort; stats != nil {
stats.Log("Journalling in-progress snapshot", dl.root, dl.genMarker)
}
}
// Ensure the layer didn't get stale
dl.lock.RLock()
defer dl.lock.RUnlock()
if dl.stale {
return common.Hash{}, ErrSnapshotStale
}
// Write out the generator marker
entry := journalGenerator{
Done: dl.genMarker == nil,
Marker: dl.genMarker,
}
if stats != nil {
entry.Wiping = (stats.wiping != nil)
entry.Accounts = stats.accounts
entry.Slots = stats.slots
entry.Storage = uint64(stats.storage)
}
if err := rlp.Encode(buffer, entry); err != nil {
return common.Hash{}, err
}
return dl.root, nil
}
// Journal writes the memory layer contents into a buffer to be stored in the
// database as the snapshot journal.
func (dl *diffLayer) Journal(buffer *bytes.Buffer) (common.Hash, error) {
// Journal the parent first
base, err := dl.parent.Journal(buffer)
if err != nil {
return common.Hash{}, err
}
// Ensure the layer didn't get stale
dl.lock.RLock()
defer dl.lock.RUnlock()
if dl.Stale() {
return common.Hash{}, ErrSnapshotStale
}
// Everything below was journalled, persist this layer too
if err := rlp.Encode(buffer, dl.root); err != nil {
return common.Hash{}, err
}
destructs := make([]journalDestruct, 0, len(dl.destructSet))
for hash := range dl.destructSet {
destructs = append(destructs, journalDestruct{Hash: hash})
}
if err := rlp.Encode(buffer, destructs); err != nil {
return common.Hash{}, err
}
accounts := make([]journalAccount, 0, len(dl.accountData))
for hash