// Copyright 2014 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 implements the Ethereum consensus protocol.
package core
import (
"errors"
"fmt"
"io"
"math/big"
mrand "math/rand"
"sync"
"sync/atomic"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/mclock"
"github.com/ethereum/go-ethereum/consensus"
"github.com/ethereum/go-ethereum/core/state"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/metrics"
"github.com/ethereum/go-ethereum/params"
"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/trie"
"github.com/hashicorp/golang-lru"
)
var (
blockInsertTimer = metrics.NewTimer("chain/inserts")
ErrNoGenesis = errors.New("Genesis not found in chain")
)
const (
bodyCacheLimit = 256
blockCacheLimit = 256
maxFutureBlocks = 256
maxTimeFutureBlocks = 30
badBlockLimit = 10
// BlockChainVersion ensures that an incompatible database forces a resync from scratch.
BlockChainVersion = 3
)
// BlockChain represents the canonical chain given a database with a genesis
// block. The Blockchain manages chain imports, reverts, chain reorganisations.
//
// Importing blocks in to the block chain happens according to the set of rules
// defined by the two stage Validator. Processing of blocks is done using the
// Processor which processes the included transaction. The validation of the state
// is done in the second part of the Validator. Failing results in aborting of
// the import.
//
// The BlockChain also helps in returning blocks from **any** chain included
// in the database as well as blocks that represents the canonical chain. It's
// important to note that GetBlock can return any block and does not need to be
// included in the canonical one where as GetBlockByNumber always represents the
// canonical chain.
type BlockChain struct {
config *params.ChainConfig // chain & network configuration
hc *HeaderChain
chainDb ethdb.Database
rmLogsFeed event.Feed
chainFeed event.Feed
chainSideFeed event.Feed
chainHeadFeed event.Feed
logsFeed event.Feed
scope event.SubscriptionScope
genesisBlock *types.Block
mu sync.RWMutex // global mutex for locking chain operations
chainmu sync.RWMutex // blockchain insertion lock
procmu sync.RWMutex // block processor lock
checkpoint int // checkpoint counts towards the new checkpoint
currentBlock *types.Block // Current head of the block chain
currentFastBlock *types.Block // Current head of the fast-sync chain (may be above the block chain!)
stateCache state.Database // State database to reuse between imports (contains state cache)
bodyCache *lru.Cache // Cache for the most recent block bodies
bodyRLPCache *lru.Cache // Cache for the most recent block bodies in RLP encoded format
blockCache *lru.Cache // Cache for the most recent entire blocks
futureBlocks *lru.Cache // future blocks are blocks added for later processing
quit chan struct{} // blockchain quit channel
running int32 // running must be called atomically
// procInterrupt must be atomically called
procInterrupt int32 // interrupt signaler for block processing
wg sync.WaitGroup // chain processing wait group for shutting down
engine consensus.Engine
processor Processor // block processor interface
validator Validator // block and state validator interface
vmConfig vm.Config
badBlocks *lru.Cache // Bad block cache
}
// NewBlockChain returns a fully initialised block chain using information
// available in the database. It initialises the default Ethereum Validator and
// Processor.
func NewBlockChain(chainDb ethdb.Database, config *params.ChainConfig, engine consensus.Engine, vmConfig vm.Config) (*BlockChain, error) {
bodyCache, _ := lru.New(bodyCacheLimit)
bodyRLPCache, _ := lru.New(bodyCacheLimit)
blockCache, _ := lru.New(blockCacheLimit)
futureBlocks, _ := lru.New(maxFutureBlocks)
badBlocks, _ := lru.New(badBlockLimit)
bc := &BlockChain{
config: config,
chainDb: chainDb,
stateCache: state.NewDatabase(chainDb),
quit: make(chan struct{}),
bodyCache: bodyCache,
bodyRLPCache: bodyRLPCache,
blockCache: blockCache,
futureBlocks: futureBlocks,
engine: engine,
vmConfig: vmConfig,
badBlocks: badBlocks,
}
bc.SetValidator(NewBlockValidator(config, bc, engine))
bc.SetProcessor(NewStateProcessor(config, bc, engine))
var err error
bc.hc, err = NewHeaderChain(chainDb, config, engine, bc.getProcInterrupt)
if err != nil {
return nil, err
}
bc.genesisBlock = bc.GetBlockByNumber(0)
if bc.genesisBlock == nil {
return nil, ErrNoGenesis
}
if err := bc.loadLastState(); err != nil {
return nil, err
}
// Check the current state of the block hashes and make sure that we do not have any of the bad blocks in our chain
for hash := range BadHashes {
if header := bc.GetHeaderByHash(hash); header != nil {
// get the canonical block corresponding to the offending header's number
headerByNumber := bc.GetHeaderByNumber(header.Number.Uint64())
// make sure the headerByNumber (if present) is in our current canonical chain
if headerByNumber != nil && headerByNumber.Hash() == header.Hash() {
log.Error("Found bad hash, rewinding chain", "number", header.Number, "hash", header.ParentHash)
bc.SetHead(header.Number.Uint64() - 1)
log.Error("Chain rewind was successful, resuming normal operation")
}
}
}
// Take ownership of this particular state
go bc.update()
return bc, nil
}
func (bc *BlockChain) getProcInterrupt() bool {
return atomic.LoadInt32(&bc.procInterrupt) == 1
}
// loadLastState loads the last known chain state from the database. This method
// assumes that the chain manager mutex is held.
func (bc *BlockChain) loadLastState() error {
// Restore the last known head block
head := GetHeadBlockHash(bc.chainDb)
if head == (common.Hash{}) {
// Corrupt or empty database, init from scratch
log.Warn("Empty database, resetting chain")
return bc.Reset()
}
// Make sure the entire head block is available
currentBlock := bc.GetBlockByHash(head)
if currentBlock == nil {
// Corrupt or empty database, init from scratch
log.Warn("Head block missing, resetting chain", "hash", head)
return bc.Reset()
}
// Make sure the state associated with the block is available
if _, err := state.New(currentBlock.Root(), bc.stateCache); err != nil {
// Dangling block without a state associated, init from scratch
log.Warn("Head state missing, resetting chain", "number", currentBlock.Number(), "hash", currentBlock.Hash())
return bc.Reset()
}
// Everything seems to be fine, set as the head block
bc.currentBlock = currentBlock
// Restore the last known head header
currentHeader := bc.currentBlock.Header()
if head := GetHeadHeaderHash(bc.chainDb); head != (common.Hash{}) {
if header := bc.GetHeaderByHash(head); header != nil {
currentHeader = header
}
}
bc.hc.SetCurrentHeader(currentHeader)
// Restore the last known head fast block
bc.currentFastBlock = bc.currentBlock
if head := GetHeadFastBlockHash(bc.chainDb); head != (common.Hash{}) {
if block := bc.GetBlockByHash(head); block != nil {
bc.currentFastBlock = block
}
}
// Issue a status log for the user
headerTd := bc.GetTd(currentHeader.Hash(), currentHeader.Number.Uint64())
blockTd := bc.GetTd(bc.currentBlock.Hash(), bc.currentBlock.NumberU64())
fastTd := bc.GetTd(bc.currentFastBlock.Hash(), bc.currentFastBlock.NumberU64())
log.Info("Loaded most recent local header", "number", currentHeader.Number, "hash", currentHeader.Hash(), "td", headerTd)
log.Info("Loaded most recent local full block", "number", bc.currentBlock.Number(), "hash", bc.currentBlock.Hash(), "td", blockTd)
log.Info("Loaded most recent local fast block", "number", bc.currentFastBlock.Number(), "hash", bc.currentFastBlock.Hash(), "td", fastTd)
return nil
}
// SetHead rewinds the local chain to a new head. In the case of headers, everything
// above the new head will be deleted and the new one set. In the case of blocks
// though, the head may be further rewound if block bodies are missing (non-archive
// nodes after a fast sync).
func (bc *BlockChain) SetHead(head uint64) error {
log.Warn("Rewinding blockchain", "target", head)
bc.mu.Lock()
defer bc.mu.Unlock()
// Rewind the header chain, deleting all block bodies until then
delFn := func(hash common.Hash, num uint64) {
DeleteBody(bc.chainDb, hash, num)
}
bc.hc.SetHead(head, delFn)
currentHeader := bc.hc.CurrentHeader()
// Clear out any stale content from the caches
bc.bodyCache.Purge()
bc.bodyRLPCache.Purge()
bc.blockCache.Purge()
bc.futureBlocks.Purge()
// Rewind the block chain, ensuring we don't end up with a stateless head block
if bc.currentBlock != nil && currentHeader.Number.Uint64() < bc.currentBlock.NumberU64() {
bc.currentBlock = bc.GetBlock(currentHeader.Hash(), currentHeader.Number.Uint64())
}
if bc.currentBlock != nil {
if _, err := state.New(bc.currentBlock.Root(), bc.stateCache); err != nil {
// Rewound state missing, rolled back to before pivot, reset to genesis
bc.currentBlock = nil
}
}
// Rewind the fast block in a simpleton way to the target head
if bc.currentFastBlock != nil && currentHeader.Number.Uint64() < bc.currentFastBlock.NumberU64() {
bc.currentFastBlock = bc.GetBlock(currentHeader.Hash(), currentHeader.Number.Uint64())
}
// If either blocks reached nil, reset to the genesis state
if bc.currentBlock == nil {
bc.currentBlock = bc.genesisBlock
}
if bc.currentFastBlock == nil {
bc.currentFastBlock = bc.genesisBlock
}
if err := WriteHeadBlockHash(bc.chainDb, bc.currentBlock.Hash()); err != nil {
log.Crit("Failed to reset head full block", "err", err)
}
if err := WriteHeadFastBlockHash(bc.chainDb, bc.currentFastBlock.Hash()); err != nil {
log.Crit("Failed to reset head fast block", "err", err)
}
return bc.loadLastState()
}
// FastSyncCommitHead sets the current head block to the one defined by the hash
// irrelevant what the chain contents were prior.
func (bc *BlockChain) FastSyncCommitHead(hash common.Hash) error {
// Make sure that both the block as well at its state trie exists
block := bc.GetBlockByHash(hash)
if block == nil {
return fmt.Errorf("non existent block [%x…]", hash[:4])
}
if _, err := trie.NewSecure(block.Root(), bc.chainDb, 0); err != nil {
return err
}
// If all checks out, manually set the head block
bc.mu.Lock()
bc.currentBlock = block
bc.mu.Unlock()
log.Info("Committed new head block", "number", block.Number(), "hash", hash)
return nil
}
// GasLimit returns the gas limit of the current HEAD block.
func (bc *BlockChain) GasLimit() *big.Int {
bc.mu.RLock()
defer bc.mu.RUnlock()
return bc.currentBlock.GasLimit()
}
// LastBlockHash return the hash of the HEAD block.
func (bc *BlockChain) LastBlockHash() common.Hash {
bc.mu.RLock()
defer bc.mu.RUnlock()
return bc.currentBlock.Hash()
}
// CurrentBlock retrieves the current head block of the canonical chain. The
// block is retrieved from the blockchain's internal cache.
func (bc *BlockChain) CurrentBlock() *types.Block {
bc.mu.RLock()
defer bc.mu.RUnlock()
return bc.currentBlock
}
// CurrentFastBlock retrieves the current fast-sync head block of the canonical
// chain. The block is retrieved from the blockchain's internal cache.
func (bc *BlockChain) CurrentFastBlock() *types.Block {
bc.mu.RLock()
defer bc.mu.RUnlock()
return bc.currentFastBlock
}
// Status returns status information about the current chain such as the HEAD Td,
// the HEAD hash and the hash of the genesis block.
func (bc *BlockChain) Status() (td *big.Int, currentBlock common.Hash, genesisBlock common.Hash) {
bc.mu.RLock()
defer bc.mu.RUnlock()
return bc.GetTd(bc.currentBlock.Hash(), bc.currentBlock.NumberU64()), bc.currentBlock.Hash(), bc.genesisBlock.Hash()
}
// SetProcessor sets the processor required for making state modifications.
func (bc *BlockChain) SetProcessor(processor Processor) {
bc.procmu.Lock()
defer bc.procmu.Unlock()
bc.processor = processor
}
// SetValidator sets the validator which is used to validate incoming blocks.
func (bc *BlockChain) SetValidator(validator Validator) {
bc.procmu.Lock()
defer bc.procmu.Unlock()
bc.validator = validator
}
// Validator returns the current validator.
func (bc *BlockChain) Validator() Validator {
bc.procmu.RLock()
defer bc.procmu.RUnlock()
return bc.validator
}
// Processor returns the current processor.
func (bc *BlockChain) Processor() Processor {
bc.procmu.RLock()
defer bc.procmu.RUnlock()
return bc.processor
}
// State returns a new mutable state based on the current HEAD block.
func (bc *BlockChain) State() (*state.StateDB, error) {
return bc.StateAt(bc.CurrentBlock().Root())
}
// StateAt returns a new mutable state based on a particular point in time.
func (bc *BlockChain) StateAt(root common.Hash) (*state.StateDB, error) {
return state.New(root, bc.stateCache)
}
// Reset purges the entire blockchain, restoring it to its genesis state.
func (bc *BlockChain) Reset() error {
return bc.ResetWithGenesisBlock(bc.genesisBlock)
}
// ResetWithGenesisBlock purges the entire blockchain, restoring it to the
// specified genesis state.
func (bc *BlockChain) ResetWithGenesisBlock(genesis *types.Block) error {
// Dump the entire block chain and purge the caches
if err := bc.SetHead(0); err != nil {
return err
}
bc.mu.Lock()
defer bc.mu.Unlock()
// Prepare the genesis block and reinitialise the chain
if err := bc.hc.WriteTd(genesis.Hash(), genesis.NumberU64(), genesis.Difficulty()); err != nil {
log.Crit("Failed to write genesis block TD", "err", err)
}
if err := WriteBlock(bc.chainDb, genesis); err != nil {
log.Crit("Failed to write genesis block", "err", err)
}
bc.genesisBlock = genesis
bc.insert(bc.genesisBlock)
bc.currentBlock = bc.genesisBlock
bc.hc.SetGenesis(bc.genesisBlock.Header())
bc.hc.SetCurrentHeader(bc.genesisBlock.Header())
bc.currentFastBlock = bc.genesisBlock
return nil
}
// Export writes the active chain to the given writer.
func (bc *BlockChain) Export(w io.Writer) error {
return bc.ExportN(w, uint64(0), bc.currentBlock.NumberU64())
}
// ExportN writes a subset of the active chain to the given writer.
func (bc *BlockChain) ExportN(w io.Writer, first uint64, last uint64) error {
bc.mu.RLock()
defer bc.mu.RUnlock()
if first > last {
return fmt.Errorf("export failed: first (%d) is greater than last (%d)", first, last)
}
log.Info("Exporting batch of blocks", "count", last-first+1)
for nr := first; nr <= last; nr++ {
block := bc.GetBlockByNumber(nr)
if block == nil {
return fmt.Errorf("export failed on #%d: not found", nr)
}
if err := block.EncodeRLP(w); err != nil {
return err
}
}
return nil
}
// insert injects a new head block into the current block chain. This method
// assumes that the block is indeed a true head. It will also reset the head
// header and the head fast sync block to this very same block if they are older
// or if they are on a different side chain.
//
// Note, this function assumes that the `mu` mutex is held!
func (bc *BlockChain) insert(block *types.Block) {
// If the block is on a side chain or an unknown one, force other heads onto it too
updateHeads := GetCanonicalHash(bc.chainDb, block.NumberU64()) != block.Hash()
// Add the block to the canonical chain number scheme and mark as the head
if err := WriteCanonicalHash(bc.chainDb, block.Hash(), block.NumberU64()); err != nil {
log.Crit("Failed to insert block number", "err", err)
}
if err := WriteHeadBlockHash(bc.chainDb, block.Hash()); err != nil {
log.Crit("Failed to insert head block hash", "err", err)
}
bc.currentBlock = block
// If the block is better than out head or is on a different chain, force update heads
if updateHeads {
bc.hc.SetCurrentHeader(block.Header())
if err := WriteHeadFastBlockHash(bc.chainDb, block.Hash()); err != nil {
log.Crit("Failed to insert head fast block hash", "err", err)
}
bc.currentFastBlock = block
}
}
// Genesis retrieves the chain's genesis block.
func (bc *BlockChain) Genesis() *types.Block {
return bc.genesisBlock
}
// GetBody retrieves a block body (transactions and uncles) from the database by
// hash, caching it if found.
func (bc *BlockChain) GetBody(hash common.Hash) *types.Body {
// Short circuit if the body's already in the cache, retrieve otherwise
if cached, ok := bc.bodyCache.Get(hash); ok {
body := cached.(*types.Body)
return body
}
body := GetBody(bc.chainDb, hash, bc.hc.GetBlockNumber(hash))
if body == nil {
return nil
}
// Cache the found body for next time and return
bc.bodyCache.Add(hash, body)
return body
}
// GetBodyRLP retrieves a block body in RLP encoding from the database by hash,
// caching it if found.
func (bc *BlockChain) GetBodyRLP(hash common.Hash) rlp.RawValue {
// Short circuit if the body's already in the cache, retrieve otherwise
if cached, ok := bc.bodyRLPCache.Get(hash); ok {
return cached.(rlp.RawValue)
}
body := GetBodyRLP(bc.chainDb, hash, bc.hc.GetBlockNumber(hash))
if len(body) == 0 {
return nil
}
// Cache the found body for next time and return
bc.bodyRLPCache.Add(hash, body)
return body
}
// HasBlock checks if a block is fully present in the database or not.
func (bc *BlockChain) HasBlock(hash common.Hash, number uint64) bool {
if bc.blockCache.Contains(hash) {
return true
}
ok, _ := bc.chainDb.Has(blockBodyKey(hash, number))
return ok
}
// HasBlockAndState checks if a block and associated state trie is fully present
// in the database or not, caching it if present.
func (bc *BlockChain) HasBlockAndState(hash common.Hash) bool {
// Check first that the block itself is known
block := bc.GetBlockByHash(hash)
if block == nil {
return false
}
// Ensure the associated state is also present
_, err := bc.stateCache.OpenTrie(block.Root())
return err == nil
}
// GetBlock retrieves a block from the database by hash and number,
// caching it if found.
func (bc *BlockChain) GetBlock(hash common.Hash, number uint64) *types.Block {
// Short circuit if the block's already in the cache, retrieve otherwise
if block, ok := bc.blockCache.Get(hash); ok {
return block.(*types.Block)
}
block := GetBlock(bc.chainDb, hash, number)
if block == nil {
return nil
}
// Cache the found block for next time and return
bc.blockCache.Add(block.Hash(), block)
return block
}
// GetBlockByHash retrieves a block from the database by hash, caching it if found.
func (bc *BlockChain) GetBlockByHash(hash common.Hash) *types.Block {
return bc.GetBlock(hash, bc.hc.GetBlockNumber(hash))
}
// GetBlockByNumber retrieves a block from the database by number, caching it
// (associated with its hash) if found.
func (bc *BlockChain) GetBlockByNumber(number uint64) *types.Block {
hash := GetCanonicalHash(bc.chainDb, number)
if hash == (common.Hash{}) {
return nil
}
return bc.GetBlock(hash, number)
}
// GetBlocksFromHash returns the block corresponding to hash and up to n-1 ancestors.
// [deprecated by eth/62]
func (bc *BlockChain) GetBlocksFromHash(hash common.Hash, n int) (blocks []*types.Block) {
number := bc.hc.GetBlockNumber(hash)
for i := 0; i < n; i++ {
block := bc.GetBlock(hash, number)
if block == nil {
break
}
blocks = append(blocks, block)
hash = block.ParentHash()
number--
}
return
}
// GetUnclesInChain retrieves all the uncles from a given block backwards until
// a specific distance is reached.
func (bc *BlockChain) GetUnclesInChain(block *types.Block, length int) []*types.Header {
uncles := []*types.Header{}
for i := 0; block != nil && i < length; i++ {
uncles = append(uncles, block.Uncles()...)
block = bc.GetBlock(block.ParentHash(), block.NumberU64()-1)
}
return uncles
}
// Stop stops the blockchain service. If any imports are currently in progress
// it will abort them using the procInterrupt.
func (bc *BlockChain) Stop() {
if !atomic.CompareAndSwapInt32(&bc.running, 0, 1) {
return
}
// Unsubscribe all subscriptions registered from blockchain
bc.scope.Close()
close(bc.quit)
atomic.StoreInt32(&bc.procInterrupt, 1)
bc.wg.Wait()
log.Info("Blockchain manager stopped")
}
func (bc *BlockChain) procFutureBlocks() {
blocks := make([]*types.Block, 0, bc.futureBlocks.Len())
for _, hash := range bc.futureBlocks.Keys() {
if block, exist := bc.futureBlocks.Peek(hash); exist {
blocks = append(blocks, block.(*types.Block))
}
}
if len(blocks) > 0 {
types.BlockBy(types.Number).Sort(blocks)
// Insert one by one as chain insertion needs contiguous ancestry between blocks
for i := range blocks {
bc.InsertChain(blocks[i : i+1])
}
}
}
// WriteStatus status of write
type WriteStatus byte
const (
NonStatTy WriteStatus = iota
CanonStatTy
SideStatTy
)
// Rollback is designed to remove a chain of links from the database that aren't
// certain enough to be valid.
func (bc *BlockChain) Rollback(chain []common.Hash) {
bc.mu.Lock()
defer bc.mu.Unlock()
for i := len(chain) - 1; i >= 0; i-- {
hash := chain[i]
currentHeader := bc.hc.CurrentHeader()
if currentHeader.Hash() == hash {
bc.hc.SetCurrentHeader(bc.GetHeader(currentHeader.ParentHash, currentHeader.Number.Uint64()-1))
}
if bc.currentFastBlock.Hash() == hash {
bc.currentFastBlock = bc.GetBlock(bc.currentFastBlock.ParentHash(), bc.currentFastBlock.NumberU64()-1)
WriteHeadFastBlockHash(bc.chainDb, bc.currentFastBlock.Hash())
}
if bc.currentBlock.Hash() == hash {
bc.currentBlock = bc.GetBlock(bc.currentBlock.ParentHash(), bc.currentBlock.NumberU64()-1)
WriteHeadBlockHash(bc.chainDb, bc.currentBlock.Hash())
}
}
}
// SetReceiptsData computes all the non-consensus fields of the receipts
func SetReceiptsData(config *params.ChainConfig, block *types.Block, receipts types.Receipts) {
signer := types.MakeSigner(config, block.Number())
transactions, logIndex := block.Transactions(), uint(0)
for j := 0; j < len(receipts); j++ {
// The transaction hash can be retrieved from the transaction itself
receipts[j].TxHash = transactions[j].Hash()
// The contract address can be derived from the transaction itself
if transactions[j].To() == nil {
// Deriving the signer is expensive, only do if it's actually needed
from, _ := types.Sender(signer, transactions[j])
receipts[j].ContractAddress = crypto.CreateAddress(from, transactions[j].Nonce())
}
// The used gas can be calculated based on previous receipts
if j == 0 {
receipts[j].GasUsed = new(big.Int).Set(receipts[j].CumulativeGasUsed)
} else {
receipts[j].GasUsed = new(big.Int).Sub(receipts[j].CumulativeGasUsed, receipts[j-1].CumulativeGasUsed)
}
// The derived log fields can simply be set from the block and transaction
for k := 0; k < len(receipts[j].Logs); k++ {
receipts[j].Logs[k].BlockNumber = block.NumberU64()
receipts[j].Logs[k].BlockHash = block.Hash()
receipts[j].Logs[k].TxHash = receipts[j].TxHash
receipts[j].Logs[k].TxIndex = uint(j)
receipts[j].Logs[k].Index = logIndex
logIndex++
}
}
}
// InsertReceiptChain attempts to complete an already existing header chain with
// transaction and receipt data.
func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain []types.Receipts) (int, error) {
bc.wg.Add(1)
defer bc.wg.Done()
// Do a sanity check that the provided chain is actually ordered and linked
for i := 1; i < len(blockChain); i++ {
if blockChain[i].NumberU64() != blockChain[i-1].NumberU64()+1 || blockChain[i].ParentHash() != blockChain[i-1].Hash() {
log.Error("Non contiguous receipt insert", "number", blockChain[i].Number(), "hash", blockChain[i].Hash(), "parent", blockChain[i].ParentHash(),
"prevnumber", blockChain[i-1].Number(), "prevhash", blockChain[i-1].Hash())
return 0, fmt.Errorf("non contiguous insert: item %d is #%d [%x…], item %d is #%d [%x…] (parent [%x…])", i-1, blockChain[i-1].NumberU64(),
blockChain[i-1].Hash().Bytes()[:4], i, blockChain[i].NumberU64(), blockChain[i].Hash().Bytes()[:4], blockChain[i].ParentHash().Bytes()[:4])
}
}
var (
stats = struct{ processed, ignored int32 }{}
start = time.Now()
bytes = 0
batch = bc.chainDb.NewBatch()
)
for i, block := range blockChain {
receipts := receiptChain[i]
// Short circuit insertion if shutting down or processing failed
if atomic.LoadInt32(&bc.procInterrupt) == 1 {
return 0, nil
}
// Short circuit if the owner header is unknown
if !bc.HasHeader(block.Hash(), block.NumberU64()) {
return i, fmt.Errorf("containing header #%d [%x…] unknown", block.Number(), block.Hash().Bytes()[:4])
}
// Skip if the entire data is already known
if bc.HasBlock(block.Hash(), block.NumberU64()) {
stats.ignored++
continue
}
// Compute all the non-consensus fields of the receipts
SetReceiptsData(bc.config, block, receipts)
// Write all the data out into the database
if err := WriteBody(batch, block.Hash(), block.NumberU64(), block.Body()); err != nil {
return i, fmt.Errorf("failed to write block body: %v", err)
}
if err := WriteBlockReceipts(batch, block.Hash(), block.NumberU64(), receipts); err != nil {
return i, fmt.Errorf("failed to write block receipts: %v", err)
}
if err := WriteTxLookupEntries(batch, block); err != nil {
return i, fmt.Errorf("failed to write lookup metadata: %v", err)
}
stats.processed++
if batch.ValueSize() >= ethdb.IdealBatchSize {
if err := batch.Write(); err != nil {
return 0, err
}
bytes += batch.ValueSize()
batch = bc.chainDb.NewBatch()
}
}
if batch.ValueSize() > 0 {
bytes += batch.ValueSize()
if err := batch.Write(); err != nil {
return 0, err
}
}
// Update the head fast sync block if better
bc.mu.Lock()
head := blockChain[len(blockChain)-1]
if td := bc.GetTd(head.Hash(), head.NumberU64()); td != nil { // Rewind may have occurred, skip in that case
if bc.GetTd(bc.currentFastBlock.Hash(), bc.currentFastBlock.NumberU64()).Cmp(td) < 0 {
if err := WriteHeadFastBlockHash(bc.chainDb, head.Hash()); err != nil {
log.Crit("Failed to update head fast block hash", "err", err)
}
bc.currentFastBlock = head
}
}
bc.mu.Unlock()
log.Info("Imported new block receipts",
"count", stats.processed,
"elapsed", common.PrettyDuration(time.Since(start)),
"bytes", bytes,
"number", head.Number(),
"hash", head.Hash(),
"ignored", stats.ignored)
return 0, nil
}
// WriteBlock writes the block to the chain.
func (bc *BlockChain) WriteBlockAndState(block *types.Block, receipts []*types.Receipt, state *state.StateDB) (status WriteStatus, err error) {
bc.wg.Add(1)
defer bc.wg.Done()
// Calculate the total difficulty of the block
ptd := bc.GetTd(block.ParentHash(), block.NumberU64()-1)
if ptd == nil {
return NonStatTy, consensus.ErrUnknownAncestor
}
// Make sure no inconsistent state is leaked during insertion
bc.mu.Lock()
defer bc.mu.Unlock()
localTd := bc.GetTd(bc.currentBlock.Hash(), bc.currentBlock.NumberU64())
externTd := new(big.Int).Add(block.Difficulty(), ptd)
// Irrelevant of the canonical status, write the block itself to the database
if err := bc.hc.WriteTd(block.Hash(), block.NumberU64(), externTd); err != nil {
return NonStatTy, err
}
// Write other block data using a batch.
batch := bc.chainDb.NewBatch()
if err := WriteBlock(batch, block); err != nil {
return NonStatTy, err
}
if _, err := state.CommitTo(batch, bc.config.IsEIP158(block.Number())); err != nil {
return NonStatTy, err
}
if err := WriteBlockReceipts(batch, block.Hash(), block.NumberU64(), receipts); err != nil {
return NonStatTy, err
}
// If the total difficulty is higher than our known, add it to the canonical chain
// Second clause in the if statement reduces the vulnerability to selfish mining.
// Please refer to http://www.cs.cornell.edu/~ie53/publications/btcProcFC.pdf
reorg := externTd.Cmp(localTd) > 0
if !reorg && externTd.Cmp(localTd) == 0 {
// Split same-difficulty blocks by number, then at random
reorg = block.NumberU64() < bc.currentBlock.NumberU64() || (block.NumberU64() == bc.currentBlock.NumberU64() && mrand.Float64() < 0.5)
}
if reorg {
// Reorganise the chain if the parent is not the head block
if block.ParentHash() != bc.currentBlock.Hash() {
if err := bc.reorg(bc.currentBlock, block); err != nil {
return NonStatTy, err
}
}
// Write the positional metadata for transaction and receipt lookups
if err := WriteTxLookupEntries(batch, block); err != nil {
return NonStatTy, err
}
// Write hash preimages
if err := WritePreimages(bc.chainDb, block.NumberU64(), state.Preimages()); err != nil {
return NonStatTy, err
}
status = CanonStatTy
} else {
status = SideStatTy
}
if err := batch.Write(); err != nil {
return NonStatTy, err
}
// Set new head.
if status == CanonStatTy {
bc.insert(block)
}
bc.futureBlocks.Remove(block.Hash())
return status, nil
}
// InsertChain attempts to insert the given batch of blocks in to the canonical
// chain or, otherwise, create a fork. If an error is returned it will return
// the index number of the failing block as well an error describing what went
// wrong.
//
// After insertion is done, all accumulated events will be fired.
func (bc *BlockChain) InsertChain(chain types.Blocks) (int, error) {
n, events, logs, err := bc.insertChain(chain)
bc.PostChainEvents(events, logs)
return n, err
}
// insertChain will execute the actual chain insertion and event aggregation. The
// only reason this method exists as a separate one is to make locking cleaner
// with deferred statements.
func (bc *BlockChain) insertChain(chain types.Blocks) (int, []interface{}, []*types.Log, error) {
// Do a sanity check that the provided chain is actually ordered and linked
for i := 1; i < len(chain); i++ {
if chain[i].NumberU64() != chain[i-1].NumberU64()+1 || chain[i].ParentHash() != chain[i-1].Hash() {
// Chain broke ancestry, log a messge (programming error) and skip insertion
log.Error("Non contiguous block insert", "number", chain[i].Number(), "hash", chain[i].Hash(),
"parent", chain[i].ParentHash(), "prevnumber", chain[i-1].Number(), "prevhash", chain[i-1].Hash())
return 0, nil, nil, fmt.Errorf("non contiguous insert: item %d is #%d [%x…], item %d is #%d [%x…] (parent [%x…])", i-1, chain[i-1].NumberU64(),
chain[i-1].Hash().Bytes()[:4], i, chain[i].NumberU64(), chain[i].Hash().Bytes()[:4], chain[i].ParentHash().Bytes()[:4])
}
}
// Pre-checks passed, start the full block imports
bc.wg.Add(1)
defer bc.wg.Done()
bc.chainmu.Lock()
defer bc.chainmu.Unlock()
// A queued approach to delivering events. This is generally
// faster than direct delivery and requires much less mutex
// acquiring.
var (
stats = insertStats{startTime: mclock.Now()}
events = make([]interface{}, 0, len(chain))
lastCanon *types.Block
coalescedLogs []*types.Log
)
// Start the parallel header verifier
headers := make([]*types.Header, len(chain))
seals := make([]bool, len(chain))
for i, block := range chain {
headers[i] = block.Header()
seals[i] = true
}
abort, results := bc.engine.VerifyHeaders(bc, headers, seals)
defer close(abort)
// Iterate over the blocks and insert when the verifier permits
for i, block := range chain {
// If the chain is terminating, stop processing blocks
if atomic.LoadInt32(&bc.procInterrupt) == 1 {
log.Debug("Premature abort during blocks processing")
break
}
// If the header is a banned one, straight out abort
if BadHashes[block.Hash()] {
bc.reportBlock(block, nil, ErrBlacklistedHash)
return i, events, coalescedLogs, ErrBlacklistedHash
}
// Wait for the block's verification to complete
bstart := time.Now()
err := <-results
if err == nil {
err = bc.Validator().ValidateBody(block)
}
if err != nil {
if err == ErrKnownBlock {
stats.ignored++
continue
}
if err == consensus.ErrFutureBlock {
// Allow up to MaxFuture second in the future blocks. If this limit
// is exceeded the chain is discarded and processed at a later time
// if given.
max := big.NewInt(time.Now().Unix() + maxTimeFutureBlocks)
if block.Time().Cmp(max) > 0 {
return i, events, coalescedLogs, fmt.Errorf("future block: %v > %v", block.Time(), max)
}
bc.futureBlocks.Add(block.Hash(), block)
stats.queued++
continue
}
if err == consensus.ErrUnknownAncestor && bc.futureBlocks.Contains(block.ParentHash()) {
bc.futureBlocks.Add(block.Hash(), block)
stats.queued++
continue
}
bc.reportBlock(block, nil, err)
return i, events, coalescedLogs, err
}
// Create a new statedb using the parent block and report an
// error if it fails.
var parent *types.Block
if i == 0 {
parent = bc.GetBlock(block.ParentHash(), block.NumberU64()-1)
} else {
parent = chain[i-1]
}
state, err := state.New(parent.Root(), bc.stateCache)
if err != nil {
return i, events, coalescedLogs, err
}
// Process block using the parent state as reference point.
receipts, logs, usedGas, err := bc.processor.Process(block, state, bc.vmConfig)
if err != nil {
bc.reportBlock(block, receipts, err)
return i, events, coalescedLogs, err
}
// Validate the state using the default validator
err = bc.Validator().ValidateState(block, parent, state, receipts, usedGas)
if err != nil {
bc.reportBlock(block, receipts, err)
return i, events, coalescedLogs, err
}
// Write the block to the chain and get the status.
status, err := bc.WriteBlockAndState(block, receipts, state)
if err != nil {
return i, events, coalescedLogs, err
}
switch status {
case CanonStatTy:
log.Debug("Inserted new block", "number", block.Number(), "hash", block.Hash(), "uncles", len(block.Uncles()),
"txs", len(block.Transactions()), "gas", block.GasUsed(), "elapsed", common.PrettyDuration(time.Since(bstart)))
coalescedLogs = append(coalescedLogs, logs...)
blockInsertTimer.UpdateSince(bstart)
events = append(events, ChainEvent{block, block.Hash(), logs})
lastCanon = block
case SideStatTy:
log.Debug("Inserted forked block", "number", block.Number(), "hash", block.Hash(), "diff", block.Difficulty(), "elapsed",
common.PrettyDuration(time.Since(bstart)), "txs", len(block.Transactions()), "gas", block.GasUsed(), "uncles", len(block.Uncles()))
blockInsertTimer.UpdateSince(bstart)
events = append(events, ChainSideEvent{block})
}
stats.processed++
stats.usedGas += usedGas.Uint64()
stats.report(chain, i)
}
// Append a single chain head event if we've progressed the chain
if lastCanon != nil && bc.LastBlockHash() == lastCanon.Hash() {
events = append(events, ChainHeadEvent{lastCanon})
}
return 0, events, coalescedLogs, nil
}
// insertStats tracks and reports on block insertion.
type insertStats struct {
queued, processed, ignored int
usedGas uint64
lastIndex int
startTime mclock.AbsTime
}
// statsReportLimit is the time limit during import after which we always print
// out progress. This avoids the user wondering what's going on.
const statsReportLimit = 8 * time.Second
// report prints statistics if some number of blocks have been processed
// or more than a few seconds have passed since the last message.
func (st *insertStats) report(chain []*types.Block, index int) {
// Fetch the timings for the batch
var (
now = mclock.Now()
elapsed = time.Duration(now) - time.Duration(st.startTime)
)
// If we're at the last block of the batch or report period reached, log
if index == len(chain)-1 || elapsed >= statsReportLimit {
var (
end = chain[index]
txs = countTransactions(chain[st.lastIndex : index+1])
)
context := []interface{}{
"blocks", st.processed, "txs", txs, "mgas", float64(st.usedGas) / 1000000,
"elapsed", common.PrettyDuration(elapsed), "mgasps", float64(st.usedGas) * 1000 / float64(elapsed),
"number", end.Number(), "hash", end.Hash(),
}
if st.queued > 0 {
context = append(context, []interface{}{"queued", st.queued}...)
}
if st.ignored > 0 {
context = append(context, []interface{}{"ignored", st.ignored}...)
}
log.Info("Imported new chain segment", context...)
*st = insertStats{startTime: now, lastIndex: index + 1}
}
}
func countTransactions(chain []*types.Block) (c int) {
for _, b := range chain {
c += len(b.Transactions())
}
return c
}
// reorgs takes two blocks, an old chain and a new chain and will reconstruct the blocks and inserts them
// to be part of the new canonical chain and accumulates potential missing transactions and post an
// event about them
func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
var (
newChain types.Blocks
oldChain types.Blocks
commonBlock *types.Block
deletedTxs types.Transactions
deletedLogs []*types.Log
// collectLogs collects the logs that were generated during the
// processing of the block that corresponds with the given hash.
// These logs are later announced as deleted.
collectLogs = func(h common.Hash) {
// Coalesce logs and set 'Removed'.
receipts := GetBlockReceipts(bc.chainDb, h, bc.hc.GetBlockNumber(h))
for _, receipt := range receipts {
for _, log := range receipt.Logs {
del := *log
del.Removed = true
deletedLogs = append(deletedLogs, &del)
}
}
}
)
// first reduce whoever is higher bound
if oldBlock.NumberU64() > newBlock.NumberU64() {
// reduce old chain
for ; oldBlock != nil && oldBlock.NumberU64() != newBlock.NumberU64(); oldBlock = bc.GetBlock(oldBlock.ParentHash(), oldBlock.NumberU64()-1) {
oldChain = append(oldChain, oldBlock)
deletedTxs = append(deletedTxs, oldBlock.Transactions()...)
collectLogs(oldBlock.Hash())
}
} else {
// reduce new chain and append new chain blocks for inserting later on
for ; newBlock != nil && newBlock.NumberU64() != oldBlock.NumberU64(); newBlock = bc.GetBlock(newBlock.ParentHash(), newBlock.NumberU64()-1) {
newChain = append(newChain, newBlock)
}
}
if oldBlock == nil {
return fmt.Errorf("Invalid old chain")
}
if newBlock == nil {
return fmt.Errorf("Invalid new chain")
}
for {
if oldBlock.Hash() == newBlock.Hash() {
commonBlock = oldBlock
break
}
oldChain = append(oldChain, oldBlock)
newChain = append(newChain, newBlock)
deletedTxs = append(deletedTxs, oldBlock.Transactions()...)
collectLogs(oldBlock.Hash())
oldBlock, newBlock = bc.GetBlock(oldBlock.ParentHash(), oldBlock.NumberU64()-1), bc.GetBlock(newBlock.ParentHash(), newBlock.NumberU64()-1)
if oldBlock == nil {
return fmt.Errorf("Invalid old chain")
}
if newBlock == nil {
return fmt.Errorf("Invalid new chain")
}
}
// Ensure the user sees large reorgs
if len(oldChain) > 0 && len(newChain) > 0 {
logFn := log.Debug
if len(oldChain) > 63 {
logFn = log.Warn
}
logFn("Chain split detected", "number", commonBlock.Number(), "hash", commonBlock.Hash(),
"drop", len(oldChain), "dropfrom", oldChain[0].Hash(), "add", len(newChain), "addfrom", newChain[0].Hash())
} else {
log.Error("Impossible reorg, please file an issue", "oldnum", oldBlock.Number(), "oldhash", oldBlock.Hash(), "newnum", newBlock.Number(), "newhash", newBlock.Hash())
}
var addedTxs types.Transactions
// insert blocks. Order does not matter. Last block will be written in ImportChain itself which creates the new head properly
for _, block := range newChain {
// insert the block in the canonical way, re-writing history
bc.insert(block)
// write lookup entries for hash based transaction/receipt searches
if err := WriteTxLookupEntries(bc.chainDb, block); err != nil {
return err
}
addedTxs = append(addedTxs, block.Transactions()...)
}
// calculate the difference between deleted and added transactions
diff := types.TxDifference(deletedTxs, addedTxs)
// When transactions get deleted from the database that means the
// receipts that were created in the fork must also be deleted
for _, tx := range diff {
DeleteTxLookupEntry(bc.chainDb, tx.Hash())
}
if len(deletedLogs) > 0 {
go bc.rmLogsFeed.Send(RemovedLogsEvent{deletedLogs})
}
if len(oldChain) > 0 {
go func() {
for _, block := range oldChain {
bc.chainSideFeed.Send(ChainSideEvent{Block: block})
}
}()
}
return nil
}
// PostChainEvents iterates over the events generated by a chain insertion and
// posts them into the event feed.
// TODO: Should not expose PostChainEvents. The chain events should be posted in WriteBlock.
func (bc *BlockChain) PostChainEvents(events []interface{}, logs []*types.Log) {
// post event logs for further processing
if logs != nil {
bc.logsFeed.Send(logs)
}
for _, event := range events {
switch ev := event.(type) {
case ChainEvent:
bc.chainFeed.Send(ev)
case ChainHeadEvent:
bc.chainHeadFeed.Send(ev)
case ChainSideEvent:
bc.chainSideFeed.Send(ev)
}
}
}
func (bc *BlockChain) update() {
futureTimer := time.NewTicker(5 * time.Second)
defer futureTimer.Stop()
for {
select {
case <-futureTimer.C:
bc.procFutureBlocks()
case <-bc.quit:
return
}
}
}
// BadBlockArgs represents the entries in the list returned when bad blocks are queried.
type BadBlockArgs struct {
Hash common.Hash `json:"hash"`
Header *types.Header `json:"header"`
}
// BadBlocks returns a list of the last 'bad blocks' that the client has seen on the network
func (bc *BlockChain) BadBlocks() ([]BadBlockArgs, error) {
headers := make([]BadBlockArgs, 0, bc.badBlocks.Len())
for _, hash := range bc.badBlocks.Keys() {
if hdr, exist := bc.badBlocks.Peek(hash); exist {
header := hdr.(*types.Header)
headers = append(headers, BadBlockArgs{header.Hash(), header})
}
}
return headers, nil
}
// addBadBlock adds a bad block to the bad-block LRU cache
func (bc *BlockChain) addBadBlock(block *types.Block) {
bc.badBlocks.Add(block.Header().Hash(), block.Header())
}
// reportBlock logs a bad block error.
func (bc *BlockChain) reportBlock(block *types.Block, receipts types.Receipts, err error) {
bc.addBadBlock(block)
var receiptString string
for _, receipt := range receipts {
receiptString += fmt.Sprintf("\t%v\n", receipt)
}
log.Error(fmt.Sprintf(`
########## BAD BLOCK #########
Chain config: %v
Number: %v
Hash: 0x%x
%v
Error: %v
##############################
`, bc.config, block.Number(), block.Hash(), receiptString, err))
}
// InsertHeaderChain attempts to insert the given header chain in to the local
// chain, possibly creating a reorg. If an error is returned, it will return the
// index number of the failing header as well an error describing what went wrong.
//
// The verify parameter can be used to fine tune whether nonce verification
// should be done or not. The reason behind the optional check is because some
// of the header retrieval mechanisms already need to verify nonces, as well as
// because nonces can be verified sparsely, not needing to check each.
func (bc *BlockChain) InsertHeaderChain(chain []*types.Header, checkFreq int) (int, error) {
start := time.Now()
if i, err := bc.hc.ValidateHeaderChain(chain, checkFreq); err != nil {
return i, err
}
// Make sure only one thread manipulates the chain at once
bc.chainmu.Lock()
defer bc.chainmu.Unlock()
bc.wg.Add(1)
defer bc.wg.Done()
whFunc := func(header *types.Header) error {
bc.mu.Lock()
defer bc.mu.Unlock()
_, err := bc.hc.WriteHeader(header)
return err
}
return bc.hc.InsertHeaderChain(chain, whFunc, start)
}
// writeHeader writes a header into the local chain, given that its parent is
// already known. If the total difficulty of the newly inserted header becomes
// greater than the current known TD, the canonical chain is re-routed.
//
// Note: This method is not concurrent-safe with inserting blocks simultaneously
// into the chain, as side effects caused by reorganisations cannot be emulated
// without the real blocks. Hence, writing headers directly should only be done
// in two scenarios: pure-header mode of operation (light clients), or properly
// separated header/block phases (non-archive clients).
func (bc *BlockChain) writeHeader(header *types.Header) error {
bc.wg.Add(1)
defer bc.wg.Done()
bc.mu.Lock()
defer bc.mu.Unlock()
_, err := bc.hc.WriteHeader(header)
return err
}
// CurrentHeader retrieves the current head header of the canonical chain. The
// header is retrieved from the HeaderChain's internal cache.
func (bc *BlockChain) CurrentHeader() *types.Header {
bc.mu.RLock()
defer bc.mu.RUnlock()
return bc.hc.CurrentHeader()
}
// GetTd retrieves a block's total difficulty in the canonical chain from the
// database by hash and number, caching it if found.
func (bc *BlockChain) GetTd(hash common.Hash, number uint64) *big.Int {
return bc.hc.GetTd(hash, number)
}
// GetTdByHash retrieves a block's total difficulty in the canonical chain from the
// database by hash, caching it if found.
func (bc *BlockChain) GetTdByHash(hash common.Hash) *big.Int {
return bc.hc.GetTdByHash(hash)
}
// GetHeader retrieves a block header from the database by hash and number,
// caching it if found.
func (bc *BlockChain) GetHeader(hash common.Hash, number uint64) *types.Header {
return bc.hc.GetHeader(hash, number)
}
// GetHeaderByHash retrieves a block header from the database by hash, caching it if
// found.
func (bc *BlockChain) GetHeaderByHash(hash common.Hash) *types.Header {
return bc.hc.GetHeaderByHash(hash)
}
// HasHeader checks if a block header is present in the database or not, caching
// it if present.
func (bc *BlockChain) HasHeader(hash common.Hash, number uint64) bool {
return bc.hc.HasHeader(hash, number)
}
// GetBlockHashesFromHash retrieves a number of block hashes starting at a given
// hash, fetching towards the genesis block.
func (bc *BlockChain) GetBlockHashesFromHash(hash common.Hash, max uint64) []common.Hash {
return bc.hc.GetBlockHashesFromHash(hash, max)
}
// GetHeaderByNumber retrieves a block header from the database by number,
// caching it (associated with its hash) if found.
func (bc *BlockChain) GetHeaderByNumber(number uint64) *types.Header {
return bc.hc.GetHeaderByNumber(number)
}
// Config retrieves the blockchain's chain configuration.
func (bc *BlockChain) Config() *params.ChainConfig { return bc.config }
// Engine retrieves the blockchain's consensus engine.
func (bc *BlockChain) Engine() consensus.Engine { return bc.engine }
// SubscribeRemovedLogsEvent registers a subscription of RemovedLogsEvent.
func (bc *BlockChain) SubscribeRemovedLogsEvent(ch chan<- RemovedLogsEvent) event.Subscription {
return bc.scope.Track(bc.rmLogsFeed.Subscribe(ch))
}
// SubscribeChainEvent registers a subscription of ChainEvent.
func (bc *BlockChain) SubscribeChainEvent(ch chan<- ChainEvent) event.Subscription {
return bc.scope.Track(bc.chainFeed.Subscribe(ch))
}
// SubscribeChainHeadEvent registers a subscription of ChainHeadEvent.
func (bc *BlockChain) SubscribeChainHeadEvent(ch chan<- ChainHeadEvent) event.Subscription {
return bc.scope.Track(bc.chainHeadFeed.Subscribe(ch))
}
// SubscribeChainSideEvent registers a subscription of ChainSideEvent.
func (bc *BlockChain) SubscribeChainSideEvent(ch chan<- ChainSideEvent) event.Subscription {
return bc.scope.Track(bc.chainSideFeed.Subscribe(ch))
}
// SubscribeLogsEvent registers a subscription of []*types.Log.
func (bc *BlockChain) SubscribeLogsEvent(ch chan<- []*types.Log) event.Subscription {
return bc.scope.Track(bc.logsFeed.Subscribe(ch))
}