path: root/chain/chain_manager.go

package chain

import (
    "bytes"
    "container/list"
    "fmt"
    "math/big"

    "github.com/ethereum/go-ethereum/ethutil"
    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/state"
)

var chainlogger = logger.NewLogger("CHAIN")

func AddTestNetFunds(block *Block) {
    for _, addr := range []string{
        "51ba59315b3a95761d0863b05ccc7a7f54703d99",
        "e4157b34ea9615cfbde6b4fda419828124b70c78",
        "b9c015918bdaba24b4ff057a92a3873d6eb201be",
        "6c386a4b26f73c802f34673f7248bb118f97424a",
        "cd2a3d9f938e13cd947ec05abc7fe734df8dd826",
        "2ef47100e0787b915105fd5e3f4ff6752079d5cb",
        "e6716f9544a56c530d868e4bfbacb172315bdead",
        "1a26338f0d905e295fccb71fa9ea849ffa12aaf4",
    } {
        codedAddr := ethutil.Hex2Bytes(addr)
        account := block.state.GetAccount(codedAddr)
        account.SetBalance(ethutil.Big("1606938044258990275541962092341162602522202993782792835301376")) //ethutil.BigPow(2, 200)
        block.state.UpdateStateObject(account)
    }
}

func CalcDifficulty(block, parent *Block) *big.Int {
    diff := new(big.Int)

    adjust := new(big.Int).Rsh(parent.Difficulty, 10)
    if block.Time >= parent.Time+5 {
        diff.Sub(parent.Difficulty, adjust)
    } else {
        diff.Add(parent.Difficulty, adjust)
    }

    return diff
}

type ChainManager struct {
    eth          EthManager
    genesisBlock *Block
    // Last known total difficulty
    TD *big.Int

    LastBlockNumber uint64

    CurrentBlock  *Block
    LastBlockHash []byte

    workingChain *BlockChain
}

func NewChainManager(ethereum EthManager) *ChainManager {
    bc := &ChainManager{}
    bc.genesisBlock = NewBlockFromBytes(ethutil.Encode(Genesis))
    bc.eth = ethereum

    bc.setLastBlock()

    return bc
}

func (bc *ChainManager) setLastBlock() {
    data, _ := ethutil.Config.Db.Get([]byte("LastBlock"))
    if len(data) != 0 {
        // Prep genesis
        AddTestNetFunds(bc.genesisBlock)

        block := NewBlockFromBytes(data)
        bc.CurrentBlock = block
        bc.LastBlockHash = block.Hash()
        bc.LastBlockNumber = block.Number.Uint64()

        // Set the last know difficulty (might be 0x0 as initial value, Genesis)
        bc.TD = ethutil.BigD(ethutil.Config.Db.LastKnownTD())
    } else {
        bc.Reset()
    }

    chainlogger.Infof("Last block (#%d) %x\n", bc.LastBlockNumber, bc.CurrentBlock.Hash())
}

// Block creation & chain handling
func (bc *ChainManager) NewBlock(coinbase []byte) *Block {
    var root interface{}
    hash := ZeroHash256

    if bc.CurrentBlock != nil {
        root = bc.CurrentBlock.Root()
        hash = bc.LastBlockHash
    }

    block := CreateBlock(
        root,
        hash,
        coinbase,
        ethutil.BigPow(2, 32),
        nil,
        "")

    block.MinGasPrice = big.NewInt(10000000000000)

    parent := bc.CurrentBlock
    if parent != nil {
        block.Difficulty = CalcDifficulty(block, parent)
        block.Number = new(big.Int).Add(bc.CurrentBlock.Number, ethutil.Big1)
        block.GasLimit = block.CalcGasLimit(bc.CurrentBlock)

    }

    return block
}

func (bc *ChainManager) Reset() {
    AddTestNetFunds(bc.genesisBlock)

    bc.genesisBlock.state.Trie.Sync()
    // Prepare the genesis block
    bc.add(bc.genesisBlock)
    bc.CurrentBlock = bc.genesisBlock

    bc.SetTotalDifficulty(ethutil.Big("0"))

    // Set the last know difficulty (might be 0x0 as initial value, Genesis)
    bc.TD = ethutil.BigD(ethutil.Config.Db.LastKnownTD())
}

// Add a block to the chain and record addition information
func (bc *ChainManager) add(block *Block) {
    bc.writeBlockInfo(block)

    bc.CurrentBlock = block
    bc.LastBlockHash = block.Hash()

    encodedBlock := block.RlpEncode()
    ethutil.Config.Db.Put(block.Hash(), encodedBlock)
    ethutil.Config.Db.Put([]byte("LastBlock"), encodedBlock)

    //chainlogger.Infof("Imported block #%d (%x...)\n", block.Number, block.Hash()[0:4])
}

// Accessors
func (bc *ChainManager) Genesis() *Block {
    return bc.genesisBlock
}

// Block fetching methods
func (bc *ChainManager) HasBlock(hash []byte) bool {
    data, _ := ethutil.Config.Db.Get(hash)
    return len(data) != 0
}

func (self *ChainManager) GetChainHashesFromHash(hash []byte, max uint64) (chain [][]byte) {
    block := self.GetBlock(hash)
    if block == nil {
        return
    }

    // XXX Could be optimised by using a different database which only holds hashes (i.e., linked list)
    for i := uint64(0); i < max; i++ {

        chain = append(chain, block.Hash())

        if block.Number.Cmp(ethutil.Big0) <= 0 {
            break
        }

        block = self.GetBlock(block.PrevHash)
    }

    return
}

func (self *ChainManager) GetBlock(hash []byte) *Block {
    data, _ := ethutil.Config.Db.Get(hash)
    if len(data) == 0 {
        if self.workingChain != nil {
            // Check the temp chain
            for e := self.workingChain.Front(); e != nil; e = e.Next() {
                if bytes.Compare(e.Value.(*link).block.Hash(), hash) == 0 {
                    return e.Value.(*link).block
                }
            }
        }

        return nil
    }

    return NewBlockFromBytes(data)
}

func (self *ChainManager) GetBlockByNumber(num uint64) *Block {
    block := self.CurrentBlock
    for ; block != nil; block = self.GetBlock(block.PrevHash) {
        if block.Number.Uint64() == num {
            break
        }
    }

    if block != nil && block.Number.Uint64() == 0 && num != 0 {
        return nil
    }

    return block
}

func (bc *ChainManager) SetTotalDifficulty(td *big.Int) {
    ethutil.Config.Db.Put([]byte("LTD"), td.Bytes())
    bc.TD = td
}

func (self *ChainManager) CalcTotalDiff(block *Block) (*big.Int, error) {
    parent := self.GetBlock(block.PrevHash)
    if parent == nil {
        return nil, fmt.Errorf("Unable to calculate total diff without known parent %x", block.PrevHash)
    }

    parentTd := parent.BlockInfo().TD

    uncleDiff := new(big.Int)
    for _, uncle := range block.Uncles {
        uncleDiff = uncleDiff.Add(uncleDiff, uncle.Difficulty)
    }

    td := new(big.Int)
    td = td.Add(parentTd, uncleDiff)
    td = td.Add(td, block.Difficulty)

    return td, nil
}

func (bc *ChainManager) BlockInfo(block *Block) BlockInfo {
    bi := BlockInfo{}
    data, _ := ethutil.Config.Db.Get(append(block.Hash(), []byte("Info")...))
    bi.RlpDecode(data)

    return bi
}

// Unexported method for writing extra non-essential block info to the db
func (bc *ChainManager) writeBlockInfo(block *Block) {
    bc.LastBlockNumber++
    bi := BlockInfo{Number: bc.LastBlockNumber, Hash: block.Hash(), Parent: block.PrevHash, TD: bc.TD}

    // For now we use the block hash with the words "info" appended as key
    ethutil.Config.Db.Put(append(block.Hash(), []byte("Info")...), bi.RlpEncode())
}

func (bc *ChainManager) Stop() {
    if bc.CurrentBlock != nil {
        chainlogger.Infoln("Stopped")
    }
}

func (self *ChainManager) NewIterator(startHash []byte) *ChainIterator {
    return &ChainIterator{self, self.GetBlock(startHash)}
}

// This function assumes you've done your checking. No checking is done at this stage anymore
func (self *ChainManager) InsertChain(chain *BlockChain) {
    for e := chain.Front(); e != nil; e = e.Next() {
        link := e.Value.(*link)

        self.add(link.block)
        self.SetTotalDifficulty(link.td)
        self.eth.EventMux().Post(NewBlockEvent{link.block})
        self.eth.EventMux().Post(link.messages)
    }

    b, e := chain.Front(), chain.Back()
    if b != nil && e != nil {
        front, back := b.Value.(*link).block, e.Value.(*link).block
        chainlogger.Infof("Imported %d blocks. #%v (%x) / %#v (%x)", chain.Len(), front.Number, front.Hash()[0:4], back.Number, back.Hash()[0:4])
    }
}

func (self *ChainManager) TestChain(chain *BlockChain) (td *big.Int, err error) {
    self.workingChain = chain
    defer func() { self.workingChain = nil }()

    for e := chain.Front(); e != nil; e = e.Next() {
        var (
            l      = e.Value.(*link)
            block  = l.block
            parent = self.GetBlock(block.PrevHash)
        )

        if parent == nil {
            err = fmt.Errorf("incoming chain broken on hash %x\n", block.PrevHash[0:4])
            return
        }

        var messages state.Messages
        td, messages, err = self.eth.BlockManager().ProcessWithParent(block, parent)
        if err != nil {
            chainlogger.Infoln(err)
            chainlogger.Debugf("Block #%v failed (%x...)\n", block.Number, block.Hash()[0:4])
            chainlogger.Debugln(block)

            err = fmt.Errorf("incoming chain failed %v\n", err)
            return
        }
        l.td = td
        l.messages = messages
    }

    if td.Cmp(self.TD) <= 0 {
        err = &TDError{td, self.TD}
        return
    }

    self.workingChain = nil

    return
}

type link struct {
    block    *Block
    messages state.Messages
    td       *big.Int
}

type BlockChain struct {
    *list.List
}

func NewChain(blocks Blocks) *BlockChain {
    chain := &BlockChain{list.New()}

    for _, block := range blocks {
        chain.PushBack(&link{block, nil, nil})
    }

    return chain
}

func (self *BlockChain) RlpEncode() []byte {
    dat := make([]interface{}, 0)
    for e := self.Front(); e != nil; e = e.Next() {
        dat = append(dat, e.Value.(*link).block.RlpData())
    }

    return ethutil.Encode(dat)
}

type ChainIterator struct {
    cm    *ChainManager
    block *Block // current block in the iterator
}

func (self *ChainIterator) Prev() *Block {
    self.block = self.cm.GetBlock(self.block.PrevHash)
    return self.block
}