agent 是具体执行挖矿的对象。 它执行的流程就是，接受计算好了的区块头， 计算mixhash和nonce， 把挖矿好的区块头返回。
构造CpuAgent, 一般情况下不会使用CPU来进行挖矿，一般来说挖矿都是使用的专门的GPU进行挖矿， GPU挖矿的代码不会在这里体现。
type CpuAgent struct {
mu sync.Mutex
workCh chan *Work // 接受挖矿任务的通道
stop chan struct{}
quitCurrentOp chan struct{}
returnCh chan<- *Result // 挖矿完成后的返回channel
chain consensus.ChainReader // 获取区块链的信息
engine consensus.Engine // 一致性引擎，这里指的是Pow引擎
isMining int32 // isMining indicates whether the agent is currently mining
}
func NewCpuAgent(chain consensus.ChainReader, engine consensus.Engine) *CpuAgent {
miner := &CpuAgent{
chain: chain,
engine: engine,
stop: make(chan struct{}, 1),
workCh: make(chan *Work, 1),
}
return miner
}
设置返回值channel和得到Work的channel， 方便外界传值和得到返回信息。
func (self *CpuAgent) Work() chan<- *Work { return self.workCh }
func (self *CpuAgent) SetReturnCh(ch chan<- *Result) { self.returnCh = ch }
启动和消息循环，如果已经启动挖矿，那么直接退出， 否则启动update 这个goroutine update 从workCh接受任务，进行挖矿，或者是接受退出信息，退出。
func (self *CpuAgent) Start() {
if !atomic.CompareAndSwapInt32(&self.isMining, 0, 1) {
return // agent already started
}
go self.update()
}
func (self *CpuAgent) update() {
out:
for {
select {
case work := <-self.workCh:
self.mu.Lock()
if self.quitCurrentOp != nil {
close(self.quitCurrentOp)
}
self.quitCurrentOp = make(chan struct{})
go self.mine(work, self.quitCurrentOp)
self.mu.Unlock()
case <-self.stop:
self.mu.Lock()
if self.quitCurrentOp != nil {
close(self.quitCurrentOp)
self.quitCurrentOp = nil
}
self.mu.Unlock()
break out
}
}
}
mine, 挖矿，调用一致性引擎进行挖矿， 如果挖矿成功，把消息发送到returnCh上面。
func (self *CpuAgent) mine(work *Work, stop <-chan struct{}) {
if result, err := self.engine.Seal(self.chain, work.Block, stop); result != nil {
log.Info("Successfully sealed new block", "number", result.Number(), "hash", result.Hash())
self.returnCh <- &Result{work, result}
} else {
if err != nil {
log.Warn("Block sealing failed", "err", err)
}
self.returnCh <- nil
}
}
GetHashRate， 这个函数返回当前的HashRate。
func (self *CpuAgent) GetHashRate() int64 {
if pow, ok := self.engine.(consensus.PoW); ok {
return int64(pow.Hashrate())
}
return 0
}
remote_agent 提供了一套RPC接口，可以实现远程矿工进行采矿的功能。 比如我有一个矿机，矿机内部没有运行以太坊节点，矿机首先从remote_agent获取当前的任务，然后进行挖矿计算，当挖矿完成后，提交计算结果，完成挖矿。
数据结构和构造
type RemoteAgent struct {
mu sync.Mutex
quitCh chan struct{}
workCh chan *Work // 接受任务
returnCh chan<- *Result // 结果返回
chain consensus.ChainReader
engine consensus.Engine
currentWork *Work //当前的任务
work map[common.Hash]*Work // 当前还没有提交的任务，正在计算
hashrateMu sync.RWMutex
hashrate map[common.Hash]hashrate // 正在计算的任务的hashrate
running int32 // running indicates whether the agent is active. Call atomically
}
func NewRemoteAgent(chain consensus.ChainReader, engine consensus.Engine) *RemoteAgent {
return &RemoteAgent{
chain: chain,
engine: engine,
work: make(map[common.Hash]*Work),
hashrate: make(map[common.Hash]hashrate),
}
}
启动和停止
func (a *RemoteAgent) Start() {
if !atomic.CompareAndSwapInt32(&a.running, 0, 1) {
return
}
a.quitCh = make(chan struct{})
a.workCh = make(chan *Work, 1)
go a.loop(a.workCh, a.quitCh)
}
func (a *RemoteAgent) Stop() {
if !atomic.CompareAndSwapInt32(&a.running, 1, 0) {
return
}
close(a.quitCh)
close(a.workCh)
}
得到输入输出的channel，这个和agent.go一样。
func (a *RemoteAgent) Work() chan<- *Work {
return a.workCh
}
func (a *RemoteAgent) SetReturnCh(returnCh chan<- *Result) {
a.returnCh = returnCh
}
loop方法,和agent.go里面做的工作比较类似， 当接收到任务的时候，就存放在currentWork字段里面。 如果84秒还没有完成一个工作，那么就删除这个工作， 如果10秒没有收到hashrate的报告，那么删除这个追踪/。
// loop monitors mining events on the work and quit channels, updating the internal
// state of the rmeote miner until a termination is requested.
//
// Note, the reason the work and quit channels are passed as parameters is because
// RemoteAgent.Start() constantly recreates these channels, so the loop code cannot
// assume data stability in these member fields.
func (a *RemoteAgent) loop(workCh chan *Work, quitCh chan struct{}) {
ticker := time.NewTicker(5 * time.Second)
defer ticker.Stop()
for {
select {
case <-quitCh:
return
case work := <-workCh:
a.mu.Lock()
a.currentWork = work
a.mu.Unlock()
case <-ticker.C:
// cleanup
a.mu.Lock()
for hash, work := range a.work {
if time.Since(work.createdAt) > 7*(12*time.Second) {
delete(a.work, hash)
}
}
a.mu.Unlock()
a.hashrateMu.Lock()
for id, hashrate := range a.hashrate {
if time.Since(hashrate.ping) > 10*time.Second {
delete(a.hashrate, id)
}
}
a.hashrateMu.Unlock()
}
}
}
GetWork，这个方法由远程矿工调用，获取当前的挖矿任务。
func (a *RemoteAgent) GetWork() ([3]string, error) {
a.mu.Lock()
defer a.mu.Unlock()
var res [3]string
if a.currentWork != nil {
block := a.currentWork.Block
res[0] = block.HashNoNonce().Hex()
seedHash := ethash.SeedHash(block.NumberU64())
res[1] = common.BytesToHash(seedHash).Hex()
// Calculate the "target" to be returned to the external miner
n := big.NewInt(1)
n.Lsh(n, 255)
n.Div(n, block.Difficulty())
n.Lsh(n, 1)
res[2] = common.BytesToHash(n.Bytes()).Hex()
a.work[block.HashNoNonce()] = a.currentWork
return res, nil
}
return res, errors.New("No work available yet, don't panic.")
}
SubmitWork, 远程矿工会调用这个方法提交挖矿的结果。 对结果进行验证之后提交到returnCh
// SubmitWork tries to inject a pow solution into the remote agent, returning
// whether the solution was accepted or not (not can be both a bad pow as well as
// any other error, like no work pending).
func (a *RemoteAgent) SubmitWork(nonce types.BlockNonce, mixDigest, hash common.Hash) bool {
a.mu.Lock()
defer a.mu.Unlock()
// Make sure the work submitted is present
work := a.work[hash]
if work == nil {
log.Info("Work submitted but none pending", "hash", hash)
return false
}
// Make sure the Engine solutions is indeed valid
result := work.Block.Header()
result.Nonce = nonce
result.MixDigest = mixDigest
if err := a.engine.VerifySeal(a.chain, result); err != nil {
log.Warn("Invalid proof-of-work submitted", "hash", hash, "err", err)
return false
}
block := work.Block.WithSeal(result)
// Solutions seems to be valid, return to the miner and notify acceptance
a.returnCh <- &Result{work, block}
delete(a.work, hash)
return true
}
SubmitHashrate, 提交hash算力
func (a *RemoteAgent) SubmitHashrate(id common.Hash, rate uint64) {
a.hashrateMu.Lock()
defer a.hashrateMu.Unlock()
a.hashrate[id] = hashrate{time.Now(), rate}
}
unconfirmed是一个数据结构，用来跟踪用户本地的挖矿信息的，比如挖出了一个块，那么等待足够的后续区块确认之后(5个)，再查看本地挖矿的区块是否包含在规范的区块链内部。
数据结构
// headerRetriever is used by the unconfirmed block set to verify whether a previously
// mined block is part of the canonical chain or not.
// headerRetriever由未确认的块组使用，以验证先前挖掘的块是否是规范链的一部分。
type headerRetriever interface {
// GetHeaderByNumber retrieves the canonical header associated with a block number.
GetHeaderByNumber(number uint64) *types.Header
}
// unconfirmedBlock is a small collection of metadata about a locally mined block
// that is placed into a unconfirmed set for canonical chain inclusion tracking.
// unconfirmedBlock 是本地挖掘区块的一个小的元数据的集合，用来放入未确认的集合用来追踪本地挖掘的区块是否被包含进入规范的区块链
type unconfirmedBlock struct {
index uint64
hash common.Hash
}
// unconfirmedBlocks implements a data structure to maintain locally mined blocks
// have have not yet reached enough maturity to guarantee chain inclusion. It is
// used by the miner to provide logs to the user when a previously mined block
// has a high enough guarantee to not be reorged out of te canonical chain.
// unconfirmedBlocks 实现了一个数据结构，用来管理本地挖掘的区块，这些区块还没有达到足够的信任度来证明他们已经被规范的区块链接受。 它用来给矿工提供信息，以便他们了解他们之前挖到的区块是否被包含进入了规范的区块链。
type unconfirmedBlocks struct {
chain headerRetriever // Blockchain to verify canonical status through 需要验证的区块链 用这个接口来获取当前的规范的区块头信息
depth uint // Depth after which to discard previous blocks 经过多少个区块之后丢弃之前的区块
blocks *ring.Ring // Block infos to allow canonical chain cross checks // 区块信息，以允许规范链交叉检查
lock sync.RWMutex // Protects the fields from concurrent access
}
// newUnconfirmedBlocks returns new data structure to track currently unconfirmed blocks.
func newUnconfirmedBlocks(chain headerRetriever, depth uint) *unconfirmedBlocks {
return &unconfirmedBlocks{
chain: chain,
depth: depth,
}
}
插入跟踪区块, 当矿工挖到一个区块的时候调用， index是区块的高度， hash是区块的hash值。
// Insert adds a new block to the set of unconfirmed ones.
func (set *unconfirmedBlocks) Insert(index uint64, hash common.Hash) {
// If a new block was mined locally, shift out any old enough blocks
// 如果一个本地的区块挖到了，那么移出已经超过depth的区块
set.Shift(index)
// Create the new item as its own ring
// 循环队列的操作。
item := ring.New(1)
item.Value = &unconfirmedBlock{
index: index,
hash: hash,
}
// Set as the initial ring or append to the end
set.lock.Lock()
defer set.lock.Unlock()
if set.blocks == nil {
set.blocks = item
} else {
// 移动到循环队列的最后一个元素插入item
set.blocks.Move(-1).Link(item)
}
// Display a log for the user to notify of a new mined block unconfirmed
log.Info("🔨 mined potential block", "number", index, "hash", hash)
}
Shift方法会删除那些index超过传入的index-depth的区块，并检查他们是否在规范的区块链中。
// Shift drops all unconfirmed blocks from the set which exceed the unconfirmed sets depth
// allowance, checking them against the canonical chain for inclusion or staleness
// report.
func (set *unconfirmedBlocks) Shift(height uint64) {
set.lock.Lock()
defer set.lock.Unlock()
for set.blocks != nil {
// Retrieve the next unconfirmed block and abort if too fresh
// 因为blocks中的区块都是按顺序排列的。排在最开始的肯定是最老的区块。
// 所以每次只需要检查最开始的那个区块，如果处理完了，就从循环队列里面摘除。
next := set.blocks.Value.(*unconfirmedBlock)
if next.index+uint64(set.depth) > height { // 如果足够老了。
break
}
// Block seems to exceed depth allowance, check for canonical status
// 查询 那个区块高度的区块头
header := set.chain.GetHeaderByNumber(next.index)
switch {
case header == nil:
log.Warn("Failed to retrieve header of mined block", "number", next.index, "hash", next.hash)
case header.Hash() == next.hash: // 如果区块头就等于我们自己，
log.Info("🔗 block reached canonical chain", "number", next.index, "hash", next.hash)
default: // 否则说明我们在侧链上面。
log.Info("⑂ block became a side fork", "number", next.index, "hash", next.hash)
}
// Drop the block out of the ring
// 从循环队列删除
if set.blocks.Value == set.blocks.Next().Value {
// 如果当前的值就等于我们自己，说明只有循环队列只有一个元素，那么设置未nil
set.blocks = nil
} else {
// 否则移动到最后，然后删除一个，再移动到最前。
set.blocks = set.blocks.Move(-1)
set.blocks.Unlink(1)
set.blocks = set.blocks.Move(1)
}
}
}
worker 内部包含了很多agent，可以包含之前提到的agent和remote_agent。 worker同时负责构建区块和对象。同时把任务提供给agent。
数据结构：
Agent接口
// Agent can register themself with the worker
type Agent interface {
Work() chan<- *Work
SetReturnCh(chan<- *Result)
Stop()
Start()
GetHashRate() int64
}
Work结构，Work存储了工作者的当时的环境，并且持有所有的暂时的状态信息。
// Work is the workers current environment and holds
// all of the current state information
type Work struct {
config *params.ChainConfig
signer types.Signer // 签名者
state *state.StateDB // apply state changes here 状态数据库
ancestors *set.Set // ancestor set (used for checking uncle parent validity) 祖先集合，用来检查祖先是否有效
family *set.Set // family set (used for checking uncle invalidity) 家族集合，用来检查祖先的无效性
uncles *set.Set // uncle set uncles集合
tcount int // tx count in cycle 这个周期的交易数量
Block *types.Block // the new block //新的区块
header *types.Header // 区块头
txs []*types.Transaction // 交易
receipts []*types.Receipt // 收据
createdAt time.Time // 创建时间
}
type Result struct { //结果
Work *Work
Block *types.Block
}
worker
// worker is the main object which takes care of applying messages to the new state
// 工作者是负责将消息应用到新状态的主要对象
type worker struct {
config *params.ChainConfig
engine consensus.Engine
mu sync.Mutex
// update loop
mux *event.TypeMux
txCh chan core.TxPreEvent // 用来接受txPool里面的交易的通道
txSub event.Subscription // 用来接受txPool里面的交易的订阅器
chainHeadCh chan core.ChainHeadEvent // 用来接受区块头的通道
chainHeadSub event.Subscription
chainSideCh chan core.ChainSideEvent // 用来接受一个区块链从规范区块链移出的通道
chainSideSub event.Subscription
wg sync.WaitGroup
agents map[Agent]struct{} // 所有的agent
recv chan *Result // agent会把结果发送到这个通道
eth Backend // eth的协议
chain *core.BlockChain // 区块链
proc core.Validator // 区块链验证器
chainDb ethdb.Database // 区块链数据库
coinbase common.Address // 挖矿者的地址
extra []byte //
snapshotMu sync.RWMutex // 快照 RWMutex（快照读写锁）
snapshotBlock *types.Block // 快照 Block
snapshotState *state.StateDB // 快照 StateDB
currentMu sync.Mutex
current *Work
uncleMu sync.Mutex
possibleUncles map[common.Hash]*types.Block //可能的叔父节点
unconfirmed *unconfirmedBlocks // set of locally mined blocks pending canonicalness confirmations
// atomic status counters
mining int32
atWork int32
}
构造
func newWorker(config *params.ChainConfig, engine consensus.Engine, coinbase common.Address, eth Backend, mux *event.TypeMux) *worker {
worker := &worker{
config: config,
engine: engine,
eth: eth,
mux: mux,
txCh: make(chan core.TxPreEvent, txChanSize), // 4096
chainHeadCh: make(chan core.ChainHeadEvent, chainHeadChanSize), // 10
chainSideCh: make(chan core.ChainSideEvent, chainSideChanSize), // 10
chainDb: eth.ChainDb(),
recv: make(chan *Result, resultQueueSize), // 10
chain: eth.BlockChain(),
proc: eth.BlockChain().Validator(),
possibleUncles: make(map[common.Hash]*types.Block),
coinbase: coinbase,
agents: make(map[Agent]struct{}),
unconfirmed: newUnconfirmedBlocks(eth.BlockChain(), miningLogAtDepth),
}
// Subscribe TxPreEvent for tx pool
worker.txSub = eth.TxPool().SubscribeTxPreEvent(worker.txCh)
// Subscribe events for blockchain
worker.chainHeadSub = eth.BlockChain().SubscribeChainHeadEvent(worker.chainHeadCh)
worker.chainSideSub = eth.BlockChain().SubscribeChainSideEvent(worker.chainSideCh)
go worker.update()
go worker.wait()
worker.commitNewWork()
return worker
}
update
func (self *worker) update() {
defer self.txSub.Unsubscribe()
defer self.chainHeadSub.Unsubscribe()
defer self.chainSideSub.Unsubscribe()
for {
// A real event arrived, process interesting content
select {
// Handle ChainHeadEvent 当接收到一个区块头的信息的时候，马上开启挖矿服务。
case <-self.chainHeadCh:
self.commitNewWork()
// Handle ChainSideEvent 接收不在规范的区块链的区块，加入到潜在的叔父集合
case ev := <-self.chainSideCh:
self.uncleMu.Lock()
self.possibleUncles[ev.Block.Hash()] = ev.Block
self.uncleMu.Unlock()
// Handle TxPreEvent 接收到txPool里面的交易信息的时候。
case ev := <-self.txCh:
// Apply transaction to the pending state if we're not mining
// 如果当前没有挖矿， 那么把交易应用到当前的状态上，以便马上开启挖矿任务。
if atomic.LoadInt32(&self.mining) == 0 {
self.currentMu.Lock()
acc, _ := types.Sender(self.current.signer, ev.Tx)
txs := map[common.Address]types.Transactions{acc: {ev.Tx}}
txset := types.NewTransactionsByPriceAndNonce(self.current.signer, txs)
self.current.commitTransactions(self.mux, txset, self.chain, self.coinbase)
self.currentMu.Unlock()
}
// System stopped
case <-self.txSub.Err():
return
case <-self.chainHeadSub.Err():
return
case <-self.chainSideSub.Err():
return
}
}
}
commitNewWork 提交新的任务
func (self *worker) commitNewWork() {
self.mu.Lock()
defer self.mu.Unlock()
self.uncleMu.Lock()
defer self.uncleMu.Unlock()
self.currentMu.Lock()
defer self.currentMu.Unlock()
tstart := time.Now()
parent := self.chain.CurrentBlock()
tstamp := tstart.Unix()
if parent.Time().Cmp(new(big.Int).SetInt64(tstamp)) >= 0 { // 不能出现比parent的时间还少的情况
tstamp = parent.Time().Int64() + 1
}
// this will ensure we're not going off too far in the future
// 我们的时间不要超过现在的时间太远， 那么等待一段时间，
// 感觉这个功能完全是为了测试实现的， 如果是真实的挖矿程序，应该不会等待。
if now := time.Now().Unix(); tstamp > now+1 {
wait := time.Duration(tstamp-now) * time.Second
log.Info("Mining too far in the future", "wait", common.PrettyDuration(wait))
time.Sleep(wait)
}
num := parent.Number()
header := &types.Header{
ParentHash: parent.Hash(),
Number: num.Add(num, common.Big1),
GasLimit: core.CalcGasLimit(parent),
GasUsed: new(big.Int),
Extra: self.extra,
Time: big.NewInt(tstamp),
}
// Only set the coinbase if we are mining (avoid spurious block rewards)
// 只有当我们挖矿的时候才设置coinbase(避免虚假的块奖励？ TODO 没懂)
if atomic.LoadInt32(&self.mining) == 1 {
header.Coinbase = self.coinbase
}
if err := self.engine.Prepare(self.chain, header); err != nil {
log.Error("Failed to prepare header for mining", "err", err)
return
}
// If we are care about TheDAO hard-fork check whether to override the extra-data or not
// 根据我们是否关心DAO硬分叉来决定是否覆盖额外的数据。
if daoBlock := self.config.DAOForkBlock; daoBlock != nil {
// Check whether the block is among the fork extra-override range
// 检查区块是否在 DAO硬分叉的范围内 [daoblock,daoblock+limit]
limit := new(big.Int).Add(daoBlock, params.DAOForkExtraRange)
if header.Number.Cmp(daoBlock) >= 0 && header.Number.Cmp(limit) < 0 {
// Depending whether we support or oppose the fork, override differently
if self.config.DAOForkSupport { // 如果我们支持DAO 那么设置保留的额外的数据
header.Extra = common.CopyBytes(params.DAOForkBlockExtra)
} else if bytes.Equal(header.Extra, params.DAOForkBlockExtra) {
header.Extra = []byte{} // If miner opposes, don't let it use the reserved extra-data // 否则不使用保留的额外数据
}
}
}
// Could potentially happen if starting to mine in an odd state.
err := self.makeCurrent(parent, header) // 用新的区块头来设置当前的状态
if err != nil {
log.Error("Failed to create mining context", "err", err)
return
}
// Create the current work task and check any fork transitions needed
work := self.current
if self.config.DAOForkSupport && self.config.DAOForkBlock != nil && self.config.DAOForkBlock.Cmp(header.Number) == 0 {
misc.ApplyDAOHardFork(work.state) // 把DAO里面的资金转移到指定的账户。
}
pending, err := self.eth.TxPool().Pending() //得到阻塞的资金
if err != nil {
log.Error("Failed to fetch pending transactions", "err", err)
return
}
// 创建交易。 这个方法后续介绍
txs := types.NewTransactionsByPriceAndNonce(self.current.signer, pending)
// 提交交易 这个方法后续介绍
work.commitTransactions(self.mux, txs, self.chain, self.coinbase)
// compute uncles for the new block.
var (
uncles []*types.Header
badUncles []common.Hash
)
for hash, uncle := range self.possibleUncles {
if len(uncles) == 2 {
break
}
if err := self.commitUncle(work, uncle.Header()); err != nil {
log.Trace("Bad uncle found and will be removed", "hash", hash)
log.Trace(fmt.Sprint(uncle))
badUncles = append(badUncles, hash)
} else {
log.Debug("Committing new uncle to block", "hash", hash)
uncles = append(uncles, uncle.Header())
}
}
for _, hash := range badUncles {
delete(self.possibleUncles, hash)
}
// Create the new block to seal with the consensus engine
// 使用给定的状态来创建新的区块，Finalize会进行区块奖励等操作
if work.Block, err = self.engine.Finalize(self.chain, header, work.state, work.txs, uncles, work.receipts); err != nil {
log.Error("Failed to finalize block for sealing", "err", err)
return
}
// We only care about logging if we're actually mining.
//
if atomic.LoadInt32(&self.mining) == 1 {
log.Info("Commit new mining work", "number", work.Block.Number(), "txs", work.tcount, "uncles", len(uncles), "elapsed", common.PrettyDuration(time.Since(tstart)))
self.unconfirmed.Shift(work.Block.NumberU64() - 1)
}
self.push(work)
}
push方法，如果我们没有在挖矿，那么直接返回，否则把任务送给每一个agent
// push sends a new work task to currently live miner agents.
func (self *worker) push(work *Work) {
if atomic.LoadInt32(&self.mining) != 1 {
return
}
for agent := range self.agents {
atomic.AddInt32(&self.atWork, 1)
if ch := agent.Work(); ch != nil {
ch <- work
}
}
}
makeCurrent，未当前的周期创建一个新的环境。
// makeCurrent creates a new environment for the current cycle.
//
func (self *worker) makeCurrent(parent *types.Block, header *types.Header) error {
state, err := self.chain.StateAt(parent.Root())
if err != nil {
return err
}
work := &Work{
config: self.config,
signer: types.NewEIP155Signer(self.config.ChainId),
state: state,
ancestors: set.New(),
family: set.New(),
uncles: set.New(),
header: header,
createdAt: time.Now(),
}
// when 08 is processed ancestors contain 07 (quick block)
for _, ancestor := range self.chain.GetBlocksFromHash(parent.Hash(), 7) {
for _, uncle := range ancestor.Uncles() {
work.family.Add(uncle.Hash())
}
work.family.Add(ancestor.Hash())
work.ancestors.Add(ancestor.Hash())
}
// Keep track of transactions which return errors so they can be removed
work.tcount = 0
self.current = work
return nil
}
commitTransactions
func (env *Work) commitTransactions(mux *event.TypeMux, txs *types.TransactionsByPriceAndNonce, bc *core.BlockChain, coinbase common.Address) {
// 由于是打包新的区块中交易，所以将总 gasPool 初始化为 env.header.GasLimit
if env.gasPool == nil {
env.gasPool = new(core.GasPool).AddGas(env.header.GasLimit)
}
var coalescedLogs []*types.Log
for {
// If we don't have enough gas for any further transactions then we're done
// 如果当前区块中所有 Gas 消耗已经使用完，则退出打包交易
if env.gasPool.Gas() < params.TxGas {
log.Trace("Not enough gas for further transactions", "have", env.gasPool, "want", params.TxGas)
break
}
// Retrieve the next transaction and abort if all done
// 检索下一笔交易，如果交易集合为空则退出 commit
tx := txs.Peek()
if tx == nil {
break
}
// Error may be ignored here. The error has already been checked
// during transaction acceptance is the transaction pool.
//
// We use the eip155 signer regardless of the current hf.
from, _ := types.Sender(env.signer, tx)
// Check whether the tx is replay protected. If we're not in the EIP155 hf
// phase, start ignoring the sender until we do.
// 请参考 https://github.com/ethereum/EIPs/blob/master/EIPS/eip-155.md
// DAO事件发生后，以太坊分裂为ETH和ETC,因为两个链上的东西一摸一样，所以在ETC
// 上面发生的交易可以拿到ETH上面进行重放， 反之亦然。 所以Vitalik提出了EIP155来避免这种情况。
if tx.Protected() && !env.config.IsEIP155(env.header.Number) {
log.Trace("Ignoring reply protected transaction", "hash", tx.Hash(), "eip155", env.config.EIP155Block)
txs.Pop()
continue
}
// Start executing the transaction
env.state.Prepare(tx.Hash(), common.Hash{}, env.tcount)
// 执行交易
err, logs := env.commitTransaction(tx, bc, coinbase, gp)
switch err {
case core.ErrGasLimitReached:
// Pop the current out-of-gas transaction without shifting in the next from the account
// 弹出整个账户的所有交易， 不处理用户的下一个交易。
log.Trace("Gas limit exceeded for current block", "sender", from)
txs.Pop()
case core.ErrNonceTooLow:
// New head notification data race between the transaction pool and miner, shift
// 移动到用户的下一个交易
log.Trace("Skipping transaction with low nonce", "sender", from, "nonce", tx.Nonce())
txs.Shift()
case core.ErrNonceTooHigh:
// Reorg notification data race between the transaction pool and miner, skip account =
// 跳过这个账户
log.Trace("Skipping account with hight nonce", "sender", from, "nonce", tx.Nonce())
txs.Pop()
case nil:
// Everything ok, collect the logs and shift in the next transaction from the same account
coalescedLogs = append(coalescedLogs, logs...)
env.tcount++
txs.Shift()
default:
// Strange error, discard the transaction and get the next in line (note, the
// nonce-too-high clause will prevent us from executing in vain).
// 其他奇怪的错误，跳过这个交易。
log.Debug("Transaction failed, account skipped", "hash", tx.Hash(), "err", err)
txs.Shift()
}
}
if len(coalescedLogs) > 0 || env.tcount > 0 {
// make a copy, the state caches the logs and these logs get "upgraded" from pending to mined
// logs by filling in the block hash when the block was mined by the local miner. This can
// cause a race condition if a log was "upgraded" before the PendingLogsEvent is processed.
// 因为需要把log发送出去，而这边在挖矿完成后需要对log进行修改，所以拷贝一份发送出去，避免争用。
cpy := make([]*types.Log, len(coalescedLogs))
for i, l := range coalescedLogs {
cpy[i] = new(types.Log)
*cpy[i] = *l
}
go func(logs []*types.Log, tcount int) {
if len(logs) > 0 {
mux.Post(core.PendingLogsEvent{Logs: logs})
}
if tcount > 0 {
mux.Post(core.PendingStateEvent{})
}
}(cpy, env.tcount)
}
}
commitTransaction执行ApplyTransaction
func (env *Work) commitTransaction(tx *types.Transaction, bc *core.BlockChain, coinbase common.Address, gp *core.GasPool) (error, []*types.Log) {
snap := env.state.Snapshot()
receipt, _, err := core.ApplyTransaction(env.config, bc, &coinbase, gp, env.state, env.header, tx, env.header.GasUsed, vm.Config{})
if err != nil {
env.state.RevertToSnapshot(snap)
return err, nil
}
env.txs = append(env.txs, tx)
env.receipts = append(env.receipts, receipt)
return nil, receipt.Logs
}
wait函数用来接受挖矿的结果然后写入本地区块链，同时通过eth协议广播出去。
func (self *worker) wait() {
for {
mustCommitNewWork := true
for result := range self.recv {
atomic.AddInt32(&self.atWork, -1)
if result == nil {
continue
}
block := result.Block
work := result.Work
// Update the block hash in all logs since it is now available and not when the
// receipt/log of individual transactions were created.
for _, r := range work.receipts {
for _, l := range r.Logs {
l.BlockHash = block.Hash()
}
}
for _, log := range work.state.Logs() {
log.BlockHash = block.Hash()
}
stat, err := self.chain.WriteBlockAndState(block, work.receipts, work.state)
if err != nil {
log.Error("Failed writing block to chain", "err", err)
continue
}
// check if canon block and write transactions
if stat == core.CanonStatTy { // 说明已经插入到规范的区块链
// implicit by posting ChainHeadEvent
// 因为这种状态下，会发送ChainHeadEvent，会触发上面的update里面的代码，这部分代码会commitNewWork，所以在这里就不需要commit了。
mustCommitNewWork = false
}
// Broadcast the block and announce chain insertion event
// 广播区块，并且申明区块链插入事件。
self.mux.Post(core.NewMinedBlockEvent{Block: block})
var (
events []interface{}
logs = work.state.Logs()
)
events = append(events, core.ChainEvent{Block: block, Hash: block.Hash(), Logs: logs})
if stat == core.CanonStatTy {
events = append(events, core.ChainHeadEvent{Block: block})
}
self.chain.PostChainEvents(events, logs)
// Insert the block into the set of pending ones to wait for confirmations
// 插入本地跟踪列表， 查看后续的确认状态。
self.unconfirmed.Insert(block.NumberU64(), block.Hash())
if mustCommitNewWork { // TODO ?
self.commitNewWork()
}
}
}
}
miner用来对worker进行管理， 订阅外部事件，控制worker的启动和停止。
数据结构
// Backend wraps all methods required for mining.
type Backend interface {
AccountManager() *accounts.Manager
BlockChain() *core.BlockChain
TxPool() *core.TxPool
ChainDb() ethdb.Database
}
// Miner creates blocks and searches for proof-of-work values.
type Miner struct {
mux *event.TypeMux
worker *worker
coinbase common.Address
mining int32
eth Backend
engine consensus.Engine
canStart int32 // can start indicates whether we can start the mining operation
shouldStart int32 // should start indicates whether we should start after sync
}
构造, 创建了一个CPU agent 启动了miner的update goroutine
func New(eth Backend, config *params.ChainConfig, mux *event.TypeMux, engine consensus.Engine) *Miner {
miner := &Miner{
eth: eth,
mux: mux,
engine: engine,
worker: newWorker(config, engine, common.Address{}, eth, mux),
canStart: 1,
}
miner.Register(NewCpuAgent(eth.BlockChain(), engine))
go miner.update()
return miner
}
update订阅了downloader的事件， 注意这个goroutine是一个一次性的循环， 只要接收到一次downloader的downloader.DoneEvent或者 downloader.FailedEvent事件， 就会设置canStart为1. 并退出循环， 这是为了避免黑客恶意的 DOS攻击，让你不断的处于异常状态
// update keeps track of the downloader events. Please be aware that this is a one shot type of update loop.
// It's entered once and as soon as `Done` or `Failed` has been broadcasted the events are unregistered and
// the loop is exited. This to prevent a major security vuln where external parties can DOS you with blocks
// and halt your mining operation for as long as the DOS continues.
func (self *Miner) update() {
events := self.mux.Subscribe(downloader.StartEvent{}, downloader.DoneEvent{}, downloader.FailedEvent{})
out:
for ev := range events.Chan() {
switch ev.Data.(type) {
case downloader.StartEvent:
atomic.StoreInt32(&self.canStart, 0)
if self.Mining() {
self.Stop()
atomic.StoreInt32(&self.shouldStart, 1)
log.Info("Mining aborted due to sync")
}
case downloader.DoneEvent, downloader.FailedEvent:
shouldStart := atomic.LoadInt32(&self.shouldStart) == 1
atomic.StoreInt32(&self.canStart, 1)
atomic.StoreInt32(&self.shouldStart, 0)
if shouldStart {
self.Start(self.coinbase)
}
// unsubscribe. we're only interested in this event once
events.Unsubscribe()
// stop immediately and ignore all further pending events
break out
}
}
}
Start
func (self *Miner) Start(coinbase common.Address) {
atomic.StoreInt32(&self.shouldStart, 1) // shouldStart 是是否应该启动
self.worker.setEtherbase(coinbase)
self.coinbase = coinbase
if atomic.LoadInt32(&self.canStart) == 0 { // canStart是否能够启动，
log.Info("Network syncing, will start miner afterwards")
return
}
atomic.StoreInt32(&self.mining, 1)
log.Info("Starting mining operation")
self.worker.start() // 启动worker 开始挖矿
self.worker.commitNewWork() //提交新的挖矿任务。
}