bsc/core/txindexer.go
2024-05-20 21:10:14 +08:00

221 lines
7.2 KiB
Go

// Copyright 2024 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 core
import (
"errors"
"fmt"
"github.com/ethereum/go-ethereum/core/rawdb"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/log"
)
// TxIndexProgress is the struct describing the progress for transaction indexing.
type TxIndexProgress struct {
Indexed uint64 // number of blocks whose transactions are indexed
Remaining uint64 // number of blocks whose transactions are not indexed yet
}
// Done returns an indicator if the transaction indexing is finished.
func (progress TxIndexProgress) Done() bool {
return progress.Remaining == 0
}
// txIndexer is the module responsible for maintaining transaction indexes
// according to the configured indexing range by users.
type txIndexer struct {
// limit is the maximum number of blocks from head whose tx indexes
// are reserved:
// * 0: means the entire chain should be indexed
// * N: means the latest N blocks [HEAD-N+1, HEAD] should be indexed
// and all others shouldn't.
limit uint64
db ethdb.Database
progress chan chan TxIndexProgress
term chan chan struct{}
closed chan struct{}
}
// newTxIndexer initializes the transaction indexer.
func newTxIndexer(limit uint64, chain *BlockChain) *txIndexer {
limit = 0
indexer := &txIndexer{
limit: limit,
db: chain.db,
progress: make(chan chan TxIndexProgress),
term: make(chan chan struct{}),
closed: make(chan struct{}),
}
go indexer.loop(chain)
var msg string
if limit == 0 {
msg = "entire chain"
} else {
msg = fmt.Sprintf("last %d blocks", limit)
}
log.Info("Initialized transaction indexer", "range", msg)
return indexer
}
// run executes the scheduled indexing/unindexing task in a separate thread.
// If the stop channel is closed, the task should be terminated as soon as
// possible, the done channel will be closed once the task is finished.
func (indexer *txIndexer) run(tail *uint64, head uint64, stop chan struct{}, done chan struct{}) {
defer func() { close(done) }()
// Short circuit if chain is empty and nothing to index.
if head == 0 {
return
}
// The tail flag is not existent, it means the node is just initialized
// and all blocks in the chain (part of them may from ancient store) are
// not indexed yet, index the chain according to the configured limit.
if tail == nil {
from := uint64(0)
if indexer.limit != 0 && head >= indexer.limit {
from = head - indexer.limit + 1
}
rawdb.IndexTransactions(indexer.db, from, head+1, stop, true)
return
}
// The tail flag is existent (which means indexes in [tail, head] should be
// present), while the whole chain are requested for indexing.
if indexer.limit == 0 || head < indexer.limit {
if *tail > 0 {
// It can happen when chain is rewound to a historical point which
// is even lower than the indexes tail, recap the indexing target
// to new head to avoid reading non-existent block bodies.
end := *tail
if end > head+1 {
end = head + 1
}
rawdb.IndexTransactions(indexer.db, 0, end, stop, true)
}
return
}
// The tail flag is existent, adjust the index range according to configured
// limit and the latest chain head.
if head-indexer.limit+1 < *tail {
// Reindex a part of missing indices and rewind index tail to HEAD-limit
rawdb.IndexTransactions(indexer.db, head-indexer.limit+1, *tail, stop, true)
} else {
// Unindex a part of stale indices and forward index tail to HEAD-limit
rawdb.UnindexTransactions(indexer.db, *tail, head-indexer.limit+1, stop, false)
}
}
// loop is the scheduler of the indexer, assigning indexing/unindexing tasks depending
// on the received chain event.
func (indexer *txIndexer) loop(chain *BlockChain) {
defer close(indexer.closed)
// Listening to chain events and manipulate the transaction indexes.
var (
stop chan struct{} // Non-nil if background routine is active.
done chan struct{} // Non-nil if background routine is active.
lastHead uint64 // The latest announced chain head (whose tx indexes are assumed created)
lastTail = rawdb.ReadTxIndexTail(indexer.db) // The oldest indexed block, nil means nothing indexed
headCh = make(chan ChainHeadEvent)
sub = chain.SubscribeChainHeadEvent(headCh)
)
defer sub.Unsubscribe()
// Launch the initial processing if chain is not empty (head != genesis).
// This step is useful in these scenarios that chain has no progress.
if head := rawdb.ReadHeadBlock(indexer.db); head != nil && head.Number().Uint64() != 0 {
stop = make(chan struct{})
done = make(chan struct{})
lastHead = head.Number().Uint64()
go indexer.run(rawdb.ReadTxIndexTail(indexer.db), head.NumberU64(), stop, done)
}
for {
select {
case head := <-headCh:
if done == nil {
stop = make(chan struct{})
done = make(chan struct{})
go indexer.run(rawdb.ReadTxIndexTail(indexer.db), head.Block.NumberU64(), stop, done)
}
lastHead = head.Block.NumberU64()
case <-done:
stop = nil
done = nil
lastTail = rawdb.ReadTxIndexTail(indexer.db)
case ch := <-indexer.progress:
ch <- indexer.report(lastHead, lastTail)
case ch := <-indexer.term:
if stop != nil {
close(stop)
}
if done != nil {
log.Info("Waiting background transaction indexer to exit")
<-done
}
close(ch)
return
}
}
}
// report returns the tx indexing progress.
func (indexer *txIndexer) report(head uint64, tail *uint64) TxIndexProgress {
total := indexer.limit
if indexer.limit == 0 || total > head {
total = head + 1 // genesis included
}
var indexed uint64
if tail != nil {
indexed = head - *tail + 1
}
// The value of indexed might be larger than total if some blocks need
// to be unindexed, avoiding a negative remaining.
var remaining uint64
if indexed < total {
remaining = total - indexed
}
return TxIndexProgress{
Indexed: indexed,
Remaining: remaining,
}
}
// txIndexProgress retrieves the tx indexing progress, or an error if the
// background tx indexer is already stopped.
func (indexer *txIndexer) txIndexProgress() (TxIndexProgress, error) {
ch := make(chan TxIndexProgress, 1)
select {
case indexer.progress <- ch:
return <-ch, nil
case <-indexer.closed:
return TxIndexProgress{}, errors.New("indexer is closed")
}
}
// close shutdown the indexer. Safe to be called for multiple times.
func (indexer *txIndexer) close() {
ch := make(chan struct{})
select {
case indexer.term <- ch:
<-ch
case <-indexer.closed:
}
}