github.com/linapex/ethereum-go-chinese@v0.0.0-20190316121929-f8b7a73c3fa1/eth/backend.go

//<developer>
//    <name>linapex 曹一峰</name>
//    <email>linapex@163.com</email>
//    <wx>superexc</wx>
//    <qqgroup>128148617</qqgroup>
//    <url>https://jsq.ink</url>
//    <role>pku engineer</role>
//    <date>2019-03-16 19:16:37</date>
//</624450087703023616>


//包ETH实现以太坊协议。
package eth

import (
	"errors"
	"fmt"
	"math/big"
	"runtime"
	"sync"
	"sync/atomic"

	"github.com/ethereum/go-ethereum/accounts"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/ethereum/go-ethereum/consensus"
	"github.com/ethereum/go-ethereum/consensus/clique"
	"github.com/ethereum/go-ethereum/consensus/ethash"
	"github.com/ethereum/go-ethereum/core"
	"github.com/ethereum/go-ethereum/core/bloombits"
	"github.com/ethereum/go-ethereum/core/rawdb"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/core/vm"
	"github.com/ethereum/go-ethereum/eth/downloader"
	"github.com/ethereum/go-ethereum/eth/filters"
	"github.com/ethereum/go-ethereum/eth/gasprice"
	"github.com/ethereum/go-ethereum/ethdb"
	"github.com/ethereum/go-ethereum/event"
	"github.com/ethereum/go-ethereum/internal/ethapi"
	"github.com/ethereum/go-ethereum/log"
	"github.com/ethereum/go-ethereum/miner"
	"github.com/ethereum/go-ethereum/node"
	"github.com/ethereum/go-ethereum/p2p"
	"github.com/ethereum/go-ethereum/params"
	"github.com/ethereum/go-ethereum/rlp"
	"github.com/ethereum/go-ethereum/rpc"
)

type LesServer interface {
	Start(srvr *p2p.Server)
	Stop()
	Protocols() []p2p.Protocol
	SetBloomBitsIndexer(bbIndexer *core.ChainIndexer)
}

//以太坊实施以太坊全节点服务。
type Ethereum struct {
	config      *Config
	chainConfig *params.ChainConfig

//关闭服务的通道
shutdownChan chan bool //关闭以太坊的通道

//处理程序
	txPool          *core.TxPool
	blockchain      *core.BlockChain
	protocolManager *ProtocolManager
	lesServer       LesServer

//数据库接口
chainDb ethdb.Database //区块链数据库

	eventMux       *event.TypeMux
	engine         consensus.Engine
	accountManager *accounts.Manager

bloomRequests chan chan *bloombits.Retrieval //接收Bloom数据检索请求的通道
bloomIndexer  *core.ChainIndexer             //块导入期间的Bloom索引器操作

	APIBackend *EthAPIBackend

	miner     *miner.Miner
	gasPrice  *big.Int
	etherbase common.Address

	networkID     uint64
	netRPCService *ethapi.PublicNetAPI

lock sync.RWMutex //保护可变油田（如天然气价格和以太坊）
}

func (s *Ethereum) AddLesServer(ls LesServer) {
	s.lesServer = ls
	ls.SetBloomBitsIndexer(s.bloomIndexer)
}

//新建创建新的以太坊对象（包括
//公共EythUM对象的初始化
func New(ctx *node.ServiceContext, config *Config) (*Ethereum, error) {
//确保配置值兼容且正常
	if config.SyncMode == downloader.LightSync {
		return nil, errors.New("can't run eth.Ethereum in light sync mode, use les.LightEthereum")
	}
	if !config.SyncMode.IsValid() {
		return nil, fmt.Errorf("invalid sync mode %d", config.SyncMode)
	}
	if config.MinerGasPrice == nil || config.MinerGasPrice.Cmp(common.Big0) <= 0 {
		log.Warn("Sanitizing invalid miner gas price", "provided", config.MinerGasPrice, "updated", DefaultConfig.MinerGasPrice)
		config.MinerGasPrice = new(big.Int).Set(DefaultConfig.MinerGasPrice)
	}
//组装以太坊对象
	chainDb, err := CreateDB(ctx, config, "chaindata")
	if err != nil {
		return nil, err
	}
	chainConfig, genesisHash, genesisErr := core.SetupGenesisBlockWithOverride(chainDb, config.Genesis, config.ConstantinopleOverride)
	if _, ok := genesisErr.(*params.ConfigCompatError); genesisErr != nil && !ok {
		return nil, genesisErr
	}
	log.Info("Initialised chain configuration", "config", chainConfig)

	eth := &Ethereum{
		config:         config,
		chainDb:        chainDb,
		chainConfig:    chainConfig,
		eventMux:       ctx.EventMux,
		accountManager: ctx.AccountManager,
		engine:         CreateConsensusEngine(ctx, chainConfig, &config.Ethash, config.MinerNotify, config.MinerNoverify, chainDb),
		shutdownChan:   make(chan bool),
		networkID:      config.NetworkId,
		gasPrice:       config.MinerGasPrice,
		etherbase:      config.Etherbase,
		bloomRequests:  make(chan chan *bloombits.Retrieval),
		bloomIndexer:   NewBloomIndexer(chainDb, params.BloomBitsBlocks, params.BloomConfirms),
	}

	log.Info("Initialising Ethereum protocol", "versions", ProtocolVersions, "network", config.NetworkId)

	if !config.SkipBcVersionCheck {
		bcVersion := rawdb.ReadDatabaseVersion(chainDb)
		if bcVersion != nil && *bcVersion > core.BlockChainVersion {
			return nil, fmt.Errorf("database version is v%d, Geth %s only supports v%d", *bcVersion, params.VersionWithMeta, core.BlockChainVersion)
		} else if bcVersion != nil && *bcVersion < core.BlockChainVersion {
			log.Warn("Upgrade blockchain database version", "from", *bcVersion, "to", core.BlockChainVersion)
		}
		rawdb.WriteDatabaseVersion(chainDb, core.BlockChainVersion)
	}
	var (
		vmConfig = vm.Config{
			EnablePreimageRecording: config.EnablePreimageRecording,
			EWASMInterpreter:        config.EWASMInterpreter,
			EVMInterpreter:          config.EVMInterpreter,
		}
		cacheConfig = &core.CacheConfig{Disabled: config.NoPruning, TrieCleanLimit: config.TrieCleanCache, TrieDirtyLimit: config.TrieDirtyCache, TrieTimeLimit: config.TrieTimeout}
	)
	eth.blockchain, err = core.NewBlockChain(chainDb, cacheConfig, eth.chainConfig, eth.engine, vmConfig, eth.shouldPreserve)
	if err != nil {
		return nil, err
	}
//Rewind the chain in case of an incompatible config upgrade.
	if compat, ok := genesisErr.(*params.ConfigCompatError); ok {
		log.Warn("Rewinding chain to upgrade configuration", "err", compat)
		eth.blockchain.SetHead(compat.RewindTo)
		rawdb.WriteChainConfig(chainDb, genesisHash, chainConfig)
	}
	eth.bloomIndexer.Start(eth.blockchain)

	if config.TxPool.Journal != "" {
		config.TxPool.Journal = ctx.ResolvePath(config.TxPool.Journal)
	}
	eth.txPool = core.NewTxPool(config.TxPool, eth.chainConfig, eth.blockchain)

	if eth.protocolManager, err = NewProtocolManager(eth.chainConfig, config.SyncMode, config.NetworkId, eth.eventMux, eth.txPool, eth.engine, eth.blockchain, chainDb, config.Whitelist); err != nil {
		return nil, err
	}

	eth.miner = miner.New(eth, eth.chainConfig, eth.EventMux(), eth.engine, config.MinerRecommit, config.MinerGasFloor, config.MinerGasCeil, eth.isLocalBlock)
	eth.miner.SetExtra(makeExtraData(config.MinerExtraData))

	eth.APIBackend = &EthAPIBackend{eth, nil}
	gpoParams := config.GPO
	if gpoParams.Default == nil {
		gpoParams.Default = config.MinerGasPrice
	}
	eth.APIBackend.gpo = gasprice.NewOracle(eth.APIBackend, gpoParams)

	return eth, nil
}

func makeExtraData(extra []byte) []byte {
	if len(extra) == 0 {
//创建默认额外数据
		extra, _ = rlp.EncodeToBytes([]interface{}{
			uint(params.VersionMajor<<16 | params.VersionMinor<<8 | params.VersionPatch),
			"geth",
			runtime.Version(),
			runtime.GOOS,
		})
	}
	if uint64(len(extra)) > params.MaximumExtraDataSize {
		log.Warn("Miner extra data exceed limit", "extra", hexutil.Bytes(extra), "limit", params.MaximumExtraDataSize)
		extra = nil
	}
	return extra
}

//createdb创建链数据库。
func CreateDB(ctx *node.ServiceContext, config *Config, name string) (ethdb.Database, error) {
	db, err := ctx.OpenDatabase(name, config.DatabaseCache, config.DatabaseHandles)
	if err != nil {
		return nil, err
	}
	if db, ok := db.(*ethdb.LDBDatabase); ok {
		db.Meter("eth/db/chaindata/")
	}
	return db, nil
}

//CreateConsensusEngine为EUTHUM服务创建所需类型的一致性引擎实例
func CreateConsensusEngine(ctx *node.ServiceContext, chainConfig *params.ChainConfig, config *ethash.Config, notify []string, noverify bool, db ethdb.Database) consensus.Engine {
//如果要求提供授权证明，请将其设置为
	if chainConfig.Clique != nil {
		return clique.New(chainConfig.Clique, db)
	}
//否则承担工作证明
	switch config.PowMode {
	case ethash.ModeFake:
		log.Warn("Ethash used in fake mode")
		return ethash.NewFaker()
	case ethash.ModeTest:
		log.Warn("Ethash used in test mode")
		return ethash.NewTester(nil, noverify)
	case ethash.ModeShared:
		log.Warn("Ethash used in shared mode")
		return ethash.NewShared()
	default:
		engine := ethash.New(ethash.Config{
			CacheDir:       ctx.ResolvePath(config.CacheDir),
			CachesInMem:    config.CachesInMem,
			CachesOnDisk:   config.CachesOnDisk,
			DatasetDir:     config.DatasetDir,
			DatasetsInMem:  config.DatasetsInMem,
			DatasetsOnDisk: config.DatasetsOnDisk,
		}, notify, noverify)
engine.SetThreads(-1) //禁用CPU挖掘
		return engine
	}
}

//API返回以太坊包提供的RPC服务集合。
//注意，其中一些服务可能需要转移到其他地方。
func (s *Ethereum) APIs() []rpc.API {
	apis := ethapi.GetAPIs(s.APIBackend)

//附加由共识引擎显式公开的任何API
	apis = append(apis, s.engine.APIs(s.BlockChain())...)

//附加所有本地API并返回
	return append(apis, []rpc.API{
		{
			Namespace: "eth",
			Version:   "1.0",
			Service:   NewPublicEthereumAPI(s),
			Public:    true,
		}, {
			Namespace: "eth",
			Version:   "1.0",
			Service:   NewPublicMinerAPI(s),
			Public:    true,
		}, {
			Namespace: "eth",
			Version:   "1.0",
			Service:   downloader.NewPublicDownloaderAPI(s.protocolManager.downloader, s.eventMux),
			Public:    true,
		}, {
			Namespace: "miner",
			Version:   "1.0",
			Service:   NewPrivateMinerAPI(s),
			Public:    false,
		}, {
			Namespace: "eth",
			Version:   "1.0",
			Service:   filters.NewPublicFilterAPI(s.APIBackend, false),
			Public:    true,
		}, {
			Namespace: "admin",
			Version:   "1.0",
			Service:   NewPrivateAdminAPI(s),
		}, {
			Namespace: "debug",
			Version:   "1.0",
			Service:   NewPublicDebugAPI(s),
			Public:    true,
		}, {
			Namespace: "debug",
			Version:   "1.0",
			Service:   NewPrivateDebugAPI(s.chainConfig, s),
		}, {
			Namespace: "net",
			Version:   "1.0",
			Service:   s.netRPCService,
			Public:    true,
		},
	}...)
}

func (s *Ethereum) ResetWithGenesisBlock(gb *types.Block) {
	s.blockchain.ResetWithGenesisBlock(gb)
}

func (s *Ethereum) Etherbase() (eb common.Address, err error) {
	s.lock.RLock()
	etherbase := s.etherbase
	s.lock.RUnlock()

	if etherbase != (common.Address{}) {
		return etherbase, nil
	}
	if wallets := s.AccountManager().Wallets(); len(wallets) > 0 {
		if accounts := wallets[0].Accounts(); len(accounts) > 0 {
			etherbase := accounts[0].Address

			s.lock.Lock()
			s.etherbase = etherbase
			s.lock.Unlock()

			log.Info("Etherbase automatically configured", "address", etherbase)
			return etherbase, nil
		}
	}
	return common.Address{}, fmt.Errorf("etherbase must be explicitly specified")
}

//IsLocalBlock检查是否挖掘指定的块
//根据当地矿工的账户。
//
//我们将两种类型的账户视为本地矿工账户：以太坊
//以及通过'txpool.locals'标志指定的帐户。
func (s *Ethereum) isLocalBlock(block *types.Block) bool {
	author, err := s.engine.Author(block.Header())
	if err != nil {
		log.Warn("Failed to retrieve block author", "number", block.NumberU64(), "hash", block.Hash(), "err", err)
		return false
	}
//检查给定地址是否为etherbase。
	s.lock.RLock()
	etherbase := s.etherbase
	s.lock.RUnlock()
	if author == etherbase {
		return true
	}
//检查给定地址是否由“txPo.本地”指定
//CLI标志。
	for _, account := range s.config.TxPool.Locals {
		if account == author {
			return true
		}
	}
	return false
}

//是否应检查是否应保留给定的块
//during the chain reorg depending on whether the author of block
//是本地帐户。
func (s *Ethereum) shouldPreserve(block *types.Block) bool {
//我们为什么要禁用对集团的自重组保护？
//是否可能导致僵局？
//
//例如，如果有7个可用的签名者
//
//R1A
//R2B
//R3C
//R4D
//R5 A[X]F G/克
//R6[X]
//
//In the round5, the inturn signer E is offline, so the worst case
//是A、F和G在Round5块上签名并拒绝对手的块
//在Round6中，最后一个可用的签名者B是离线的，整个
//网络被卡住了。
	if _, ok := s.engine.(*clique.Clique); ok {
		return false
	}
	return s.isLocalBlock(block)
}

//setetherbase设置挖掘奖励地址。
func (s *Ethereum) SetEtherbase(etherbase common.Address) {
	s.lock.Lock()
	s.etherbase = etherbase
	s.lock.Unlock()

	s.miner.SetEtherbase(etherbase)
}

//StartMining使用给定数量的CPU线程启动Miner。中频开采
//已经运行，此方法调整允许使用的线程数。
//并更新交易池所需的最低价格。
func (s *Ethereum) StartMining(threads int) error {
//更新共识引擎中的线程计数
	type threaded interface {
		SetThreads(threads int)
	}
	if th, ok := s.engine.(threaded); ok {
		log.Info("Updated mining threads", "threads", threads)
		if threads == 0 {
threads = -1 //从内部禁用矿工
		}
		th.SetThreads(threads)
	}
//如果矿工没有运行，初始化它
	if !s.IsMining() {
//将初始价格点传播到交易池
		s.lock.RLock()
		price := s.gasPrice
		s.lock.RUnlock()
		s.txPool.SetGasPrice(price)

//配置本地挖掘地址
		eb, err := s.Etherbase()
		if err != nil {
			log.Error("Cannot start mining without etherbase", "err", err)
			return fmt.Errorf("etherbase missing: %v", err)
		}
		if clique, ok := s.engine.(*clique.Clique); ok {
			wallet, err := s.accountManager.Find(accounts.Account{Address: eb})
			if wallet == nil || err != nil {
				log.Error("Etherbase account unavailable locally", "err", err)
				return fmt.Errorf("signer missing: %v", err)
			}
			clique.Authorize(eb, wallet.SignHash)
		}
//如果开始挖掘，我们可以禁用事务拒绝机制。
//介绍速度同步时间。
		atomic.StoreUint32(&s.protocolManager.acceptTxs, 1)

		go s.miner.Start(eb)
	}
	return nil
}

//在共识引擎级别和
//在块创建级别。
func (s *Ethereum) StopMining() {
//更新共识引擎中的线程计数
	type threaded interface {
		SetThreads(threads int)
	}
	if th, ok := s.engine.(threaded); ok {
		th.SetThreads(-1)
	}
//停止创建块本身
	s.miner.Stop()
}

func (s *Ethereum) IsMining() bool      { return s.miner.Mining() }
func (s *Ethereum) Miner() *miner.Miner { return s.miner }

func (s *Ethereum) AccountManager() *accounts.Manager  { return s.accountManager }
func (s *Ethereum) BlockChain() *core.BlockChain       { return s.blockchain }
func (s *Ethereum) TxPool() *core.TxPool               { return s.txPool }
func (s *Ethereum) EventMux() *event.TypeMux           { return s.eventMux }
func (s *Ethereum) Engine() consensus.Engine           { return s.engine }
func (s *Ethereum) ChainDb() ethdb.Database            { return s.chainDb }
func (s *Ethereum) IsListening() bool                  { return true } //总是倾听
func (s *Ethereum) EthVersion() int                    { return int(s.protocolManager.SubProtocols[0].Version) }
func (s *Ethereum) NetVersion() uint64                 { return s.networkID }
func (s *Ethereum) Downloader() *downloader.Downloader { return s.protocolManager.downloader }

//协议实现node.service，返回所有当前配置的
//要启动的网络协议。
func (s *Ethereum) Protocols() []p2p.Protocol {
	if s.lesServer == nil {
		return s.protocolManager.SubProtocols
	}
	return append(s.protocolManager.SubProtocols, s.lesServer.Protocols()...)
}

//start实现node.service，启动
//Ethereum protocol implementation.
func (s *Ethereum) Start(srvr *p2p.Server) error {
//启动为Goroutines提供服务的Bloom钻头
	s.startBloomHandlers(params.BloomBitsBlocks)

//启动RPC服务
	s.netRPCService = ethapi.NewPublicNetAPI(srvr, s.NetVersion())

//根据服务器限制计算最大对等数
	maxPeers := srvr.MaxPeers
	if s.config.LightServ > 0 {
		if s.config.LightPeers >= srvr.MaxPeers {
			return fmt.Errorf("invalid peer config: light peer count (%d) >= total peer count (%d)", s.config.LightPeers, srvr.MaxPeers)
		}
		maxPeers -= s.config.LightPeers
	}
//如果需要，启动网络层和轻型服务器
	s.protocolManager.Start(maxPeers)
	if s.lesServer != nil {
		s.lesServer.Start(srvr)
	}
	return nil
}

//停止实现node.service，终止由
//以太坊协议。
func (s *Ethereum) Stop() error {
	s.bloomIndexer.Close()
	s.blockchain.Stop()
	s.engine.Close()
	s.protocolManager.Stop()
	if s.lesServer != nil {
		s.lesServer.Stop()
	}
	s.txPool.Stop()
	s.miner.Stop()
	s.eventMux.Stop()

	s.chainDb.Close()
	close(s.shutdownChan)
	return nil
}