path: root/ethchain/block_manager.go

package ethchain

import (
    "bytes"
    "encoding/hex"
    "fmt"
    "github.com/ethereum/eth-go/ethutil"
    _ "github.com/ethereum/eth-go/ethwire"
    "log"
    "math/big"
    "sync"
    "time"
)

type BlockProcessor interface {
    ProcessBlock(block *Block)
}

// TODO rename to state manager
type BlockManager struct {
    // Mutex for locking the block processor. Blocks can only be handled one at a time
    mutex sync.Mutex

    // The block chain :)
    bc *BlockChain

    // States for addresses. You can watch any address
    // at any given time
    addrStateStore *AddrStateStore

    // Stack for processing contracts
    stack *Stack
    // non-persistent key/value memory storage
    mem map[string]*big.Int

    TransactionPool *TxPool

    Pow PoW

    Speaker PublicSpeaker

    SecondaryBlockProcessor BlockProcessor
}

func AddTestNetFunds(block *Block) {
    for _, addr := range []string{
        "8a40bfaa73256b60764c1bf40675a99083efb075", // Gavin
        "e6716f9544a56c530d868e4bfbacb172315bdead", // Jeffrey
        "1e12515ce3e0f817a4ddef9ca55788a1d66bd2df", // Vit
        "1a26338f0d905e295fccb71fa9ea849ffa12aaf4", // Alex
    } {
        //log.Println("2^200 Wei to", addr)
        codedAddr, _ := hex.DecodeString(addr)
        addr := block.GetAddr(codedAddr)
        addr.Amount = ethutil.BigPow(2, 200)
        block.UpdateAddr(codedAddr, addr)
    }
}

func NewBlockManager(speaker PublicSpeaker) *BlockManager {
    bm := &BlockManager{
        //server: s,
        bc:             NewBlockChain(),
        stack:          NewStack(),
        mem:            make(map[string]*big.Int),
        Pow:            &EasyPow{},
        Speaker:        speaker,
        addrStateStore: NewAddrStateStore(),
    }

    if bm.bc.CurrentBlock == nil {
        AddTestNetFunds(bm.bc.genesisBlock)

        bm.bc.genesisBlock.State().Sync()
        // Prepare the genesis block
        bm.bc.Add(bm.bc.genesisBlock)

        //log.Printf("root %x\n", bm.bc.genesisBlock.State().Root)
        //bm.bc.genesisBlock.PrintHash()
    }

    log.Printf("Last block: %x\n", bm.bc.CurrentBlock.Hash())

    return bm
}

// Watches any given address and puts it in the address state store
func (bm *BlockManager) WatchAddr(addr []byte) *AddressState {
    account := bm.bc.CurrentBlock.GetAddr(addr)

    return bm.addrStateStore.Add(addr, account)
}

func (bm *BlockManager) GetAddrState(addr []byte) *AddressState {
    addrState := bm.addrStateStore.Get(addr)
    if addrState == nil {
        addrState = bm.WatchAddr(addr)
    }

    return addrState
}

func (bm *BlockManager) BlockChain() *BlockChain {
    return bm.bc
}

func (bm *BlockManager) ApplyTransactions(block *Block, txs []*Transaction) {
    // Process each transaction/contract
    for _, tx := range txs {
        // If there's no recipient, it's a contract
        if tx.IsContract() {
            block.MakeContract(tx)
        } else {
            if contract := block.GetContract(tx.Recipient); contract != nil {
                bm.ProcessContract(contract, tx, block)
            } else {
                bm.TransactionPool.ProcessTransaction(tx, block)
            }
        }
    }
}

// Block processing and validating with a given (temporarily) state
func (bm *BlockManager) ProcessBlock(block *Block) error {
    // Processing a blocks may never happen simultaneously
    bm.mutex.Lock()
    defer bm.mutex.Unlock()
    // Defer the Undo on the Trie. If the block processing happened
    // we don't want to undo but since undo only happens on dirty
    // nodes this won't happen because Commit would have been called
    // before that.
    defer bm.bc.CurrentBlock.Undo()

    hash := block.Hash()

    if bm.bc.HasBlock(hash) {
        return nil
    }

    // Check if we have the parent hash, if it isn't known we discard it
    // Reasons might be catching up or simply an invalid block
    if !bm.bc.HasBlock(block.PrevHash) && bm.bc.CurrentBlock != nil {
        return ParentError(block.PrevHash)
    }

    // Process the transactions on to current block
    bm.ApplyTransactions(bm.bc.CurrentBlock, block.Transactions())

    // Block validation
    if err := bm.ValidateBlock(block); err != nil {
        return err
    }

    // I'm not sure, but I don't know if there should be thrown
    // any errors at this time.
    if err := bm.AccumelateRewards(bm.bc.CurrentBlock, block); err != nil {
        return err
    }

    if !block.State().Cmp(bm.bc.CurrentBlock.State()) {
        return fmt.Errorf("Invalid merkle root. Expected %x, got %x", block.State().Root, bm.bc.CurrentBlock.State().Root)
    }

    // Calculate the new total difficulty and sync back to the db
    if bm.CalculateTD(block) {
        // Sync the current block's state to the database and cancelling out the deferred Undo
        bm.bc.CurrentBlock.Sync()
        // Add the block to the chain
        bm.bc.Add(block)

        /*
            ethutil.Config.Db.Put(block.Hash(), block.RlpEncode())
            bm.bc.CurrentBlock = block
            bm.LastBlockHash = block.Hash()
            bm.writeBlockInfo(block)
        */

        /*
            txs := bm.TransactionPool.Flush()
            var coded = []interface{}{}
            for _, tx := range txs {
                err := bm.TransactionPool.ValidateTransaction(tx)
                if err == nil {
                    coded = append(coded, tx.RlpEncode())
                }
            }
        */

        // Broadcast the valid block back to the wire
        //bm.Speaker.Broadcast(ethwire.MsgBlockTy, []interface{}{block.Value().Val})

        // If there's a block processor present, pass in the block for further
        // processing
        if bm.SecondaryBlockProcessor != nil {
            bm.SecondaryBlockProcessor.ProcessBlock(block)
        }

        log.Printf("[BMGR] Added block #%d (%x)\n", block.BlockInfo().Number, block.Hash())
    } else {
        fmt.Println("total diff failed")
    }

    return nil
}

func (bm *BlockManager) CalculateTD(block *Block) bool {
    uncleDiff := new(big.Int)
    for _, uncle := range block.Uncles {
        uncleDiff = uncleDiff.Add(uncleDiff, uncle.Difficulty)
    }

    // TD(genesis_block) = 0 and TD(B) = TD(B.parent) + sum(u.difficulty for u in B.uncles) + B.difficulty
    td := new(big.Int)
    td = td.Add(bm.bc.TD, uncleDiff)
    td = td.Add(td, block.Difficulty)

    // The new TD will only be accepted if the new difficulty is
    // is greater than the previous.
    if td.Cmp(bm.bc.TD) > 0 {
        // Set the new total difficulty back to the block chain
        bm.bc.SetTotalDifficulty(td)

        /*
            if ethutil.Config.Debug {
                log.Println("[BMGR] TD(block) =", td)
            }
        */

        return true
    }

    return false
}

// Validates the current block. Returns an error if the block was invalid,
// an uncle or anything that isn't on the current block chain.
// Validation validates easy over difficult (dagger takes longer time = difficult)
func (bm *BlockManager) ValidateBlock(block *Block) error {
    // TODO
    // 2. Check if the difficulty is correct

    // Check each uncle's previous hash. In order for it to be valid
    // is if it has the same block hash as the current
    previousBlock := bm.bc.GetBlock(block.PrevHash)
    for _, uncle := range block.Uncles {
        if bytes.Compare(uncle.PrevHash, previousBlock.PrevHash) != 0 {
            return ValidationError("Mismatch uncle's previous hash. Expected %x, got %x", previousBlock.PrevHash, uncle.PrevHash)
        }
    }

    diff := block.Time - bm.bc.CurrentBlock.Time
    if diff < 0 {
        return ValidationError("Block timestamp less then prev block %v", diff)
    }

    // New blocks must be within the 15 minute range of the last block.
    if diff > int64(15*time.Minute) {
        return ValidationError("Block is too far in the future of last block (> 15 minutes)")
    }

    // Verify the nonce of the block. Return an error if it's not valid
    if !bm.Pow.Verify(block.HashNoNonce(), block.Difficulty, block.Nonce) {
        return ValidationError("Block's nonce is invalid (= %v)", block.Nonce)
    }

    return nil
}

func CalculateBlockReward(block *Block, uncleLength int) *big.Int {
    base := new(big.Int)
    for i := 0; i < uncleLength; i++ {
        base.Add(base, UncleInclusionReward)
    }
    return base.Add(base, BlockReward)
}

func CalculateUncleReward(block *Block) *big.Int {
    return UncleReward
}

func (bm *BlockManager) AccumelateRewards(processor *Block, block *Block) error {
    // Get the coinbase rlp data
    addr := processor.GetAddr(block.Coinbase)
    // Reward amount of ether to the coinbase address
    addr.AddFee(CalculateBlockReward(block, len(block.Uncles)))

    processor.UpdateAddr(block.Coinbase, addr)

    for _, uncle := range block.Uncles {
        uncleAddr := processor.GetAddr(uncle.Coinbase)
        uncleAddr.AddFee(CalculateUncleReward(uncle))

        processor.UpdateAddr(uncle.Coinbase, uncleAddr)
    }

    return nil
}

func (bm *BlockManager) Stop() {
    bm.bc.Stop()
}

func (bm *BlockManager) ProcessContract(contract *Contract, tx *Transaction, block *Block) {
    // Recovering function in case the VM had any errors
    /*
        defer func() {
            if r := recover(); r != nil {
                fmt.Println("Recovered from VM execution with err =", r)
            }
        }()
    */

    vm := &Vm{}
    vm.Process(contract, NewState(block.state), RuntimeVars{
        address:     tx.Hash()[12:],
        blockNumber: block.BlockInfo().Number,
        sender:      tx.Sender(),
        prevHash:    block.PrevHash,
        coinbase:    block.Coinbase,
        time:        block.Time,
        diff:        block.Difficulty,
        txValue:     tx.Value,
        txData:      tx.Data,
    })
}