path: root/ethchain/block_chain.go

package ethchain

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

    "github.com/ethereum/eth-go/ethlog"
    "github.com/ethereum/eth-go/ethutil"
)

var chainlogger = ethlog.NewLogger("CHAIN")

type BlockChain struct {
    Ethereum EthManager
    // The famous, the fabulous Mister GENESIIIIIIS (block)
    genesisBlock *Block
    // Last known total difficulty
    TD *big.Int

    LastBlockNumber uint64

    CurrentBlock  *Block
    LastBlockHash []byte
}

func NewBlockChain(ethereum EthManager) *BlockChain {
    bc := &BlockChain{}
    bc.genesisBlock = NewBlockFromBytes(ethutil.Encode(Genesis))
    bc.Ethereum = ethereum

    bc.setLastBlock()

    return bc
}

func (bc *BlockChain) Genesis() *Block {
    return bc.genesisBlock
}

func (bc *BlockChain) NewBlock(coinbase []byte) *Block {
    var root interface{}
    var lastBlockTime int64
    hash := ZeroHash256

    if bc.CurrentBlock != nil {
        root = bc.CurrentBlock.state.Trie.Root
        hash = bc.LastBlockHash
        lastBlockTime = bc.CurrentBlock.Time
    }

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

    block.MinGasPrice = big.NewInt(10000000000000)

    parent := bc.CurrentBlock
    if parent != nil {
        diff := new(big.Int)

        adjust := new(big.Int).Rsh(parent.Difficulty, 10)
        if block.Time >= lastBlockTime+5 {
            diff.Sub(parent.Difficulty, adjust)
        } else {
            diff.Add(parent.Difficulty, adjust)
        }
        block.Difficulty = diff
        block.Number = new(big.Int).Add(bc.CurrentBlock.Number, ethutil.Big1)
        block.GasLimit = block.CalcGasLimit(bc.CurrentBlock)

    }

    return block
}

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

// TODO: At one point we might want to save a block by prevHash in the db to optimise this...
func (bc *BlockChain) HasBlockWithPrevHash(hash []byte) bool {
    block := bc.CurrentBlock

    for ; block != nil; block = bc.GetBlock(block.PrevHash) {
        if bytes.Compare(hash, block.PrevHash) == 0 {
            return true
        }
    }
    return false
}

func (bc *BlockChain) CalculateBlockTD(block *Block) *big.Int {
    blockDiff := new(big.Int)

    for _, uncle := range block.Uncles {
        blockDiff = blockDiff.Add(blockDiff, uncle.Difficulty)
    }
    blockDiff = blockDiff.Add(blockDiff, block.Difficulty)

    return blockDiff
}

func (bc *BlockChain) GenesisBlock() *Block {
    return bc.genesisBlock
}

func (self *BlockChain) 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 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.Balance = ethutil.Big("1606938044258990275541962092341162602522202993782792835301376") //ethutil.BigPow(2, 200)
        block.state.UpdateStateObject(account)
    }
}

func (bc *BlockChain) setLastBlock() {
    // Prep genesis
    AddTestNetFunds(bc.genesisBlock)

    data, _ := ethutil.Config.Db.Get([]byte("LastBlock"))
    if len(data) != 0 {
        block := NewBlockFromBytes(data)
        bc.CurrentBlock = block
        bc.LastBlockHash = block.Hash()
        bc.LastBlockNumber = block.Number.Uint64()

    } else {
        bc.genesisBlock.state.Trie.Sync()
        // Prepare the genesis block
        bc.Add(bc.genesisBlock)
        fk := append([]byte("bloom"), bc.genesisBlock.Hash()...)
        bc.Ethereum.Db().Put(fk, make([]byte, 255))
        bc.CurrentBlock = bc.genesisBlock
    }

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

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

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

// Add a block to the chain and record addition information
func (bc *BlockChain) Add(block *Block) {
    bc.writeBlockInfo(block)
    // Prepare the genesis 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)
}

func (self *BlockChain) 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 *BlockChain) GetBlock(hash []byte) *Block {
    data, _ := ethutil.Config.Db.Get(hash)
    if len(data) == 0 {
        return nil
    }

    return NewBlockFromBytes(data)
}

func (self *BlockChain) 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 *BlockChain) BlockInfoByHash(hash []byte) BlockInfo {
    bi := BlockInfo{}
    data, _ := ethutil.Config.Db.Get(append(hash, []byte("Info")...))
    bi.RlpDecode(data)

    return bi
}

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