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"
    "github.com/obscuren/secp256k1-go"
    "log"
    "math"
    "math/big"
    "strconv"
    "sync"
    "time"
)

type BlockProcessor interface {
    ProcessBlock(block *Block)
}

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

    // 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
        "93658b04240e4bd4046fd2d6d417d20f146f4b43", // 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,
    }

    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
}

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)
            bm.ProcessContract(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.State().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.State().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(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)
        }
    }()

    // Process contract
    bm.ProcContract(tx, block, func(opType OpType) bool {
        // TODO turn on once big ints are in place
        //if !block.PayFee(tx.Hash(), StepFee.Uint64()) {
        //  return false
        //}

        return true // Continue
    })
}

// Contract evaluation is done here.
func (bm *BlockManager) ProcContract(tx *Transaction, block *Block, cb TxCallback) {

    // Instruction pointer
    pc := 0
    blockInfo := bm.bc.BlockInfo(block)

    contract := block.GetContract(tx.Hash())
    if contract == nil {
        fmt.Println("Contract not found")
        return
    }

    Pow256 := ethutil.BigPow(2, 256)

    if ethutil.Config.Debug {
        fmt.Printf("#   op   arg\n")
    }
out:
    for {
        // The base big int for all calculations. Use this for any results.
        base := new(big.Int)
        // XXX Should Instr return big int slice instead of string slice?
        // Get the next instruction from the contract
        //op, _, _ := Instr(contract.state.Get(string(Encode(uint32(pc)))))
        nb := ethutil.NumberToBytes(uint64(pc), 32)
        o, _, _ := ethutil.Instr(contract.State().Get(string(nb)))
        op := OpCode(o)

        if !cb(0) {
            break
        }

        if ethutil.Config.Debug {
            fmt.Printf("%-3d %-4s\n", pc, op.String())
        }

        switch op {
        case oSTOP:
            break out
        case oADD:
            x, y := bm.stack.Popn()
            // (x + y) % 2 ** 256
            base.Add(x, y)
            base.Mod(base, Pow256)
            // Pop result back on the stack
            bm.stack.Push(base)
        case oSUB:
            x, y := bm.stack.Popn()
            // (x - y) % 2 ** 256
            base.Sub(x, y)
            base.Mod(base, Pow256)
            // Pop result back on the stack
            bm.stack.Push(base)
        case oMUL:
            x, y := bm.stack.Popn()
            // (x * y) % 2 ** 256
            base.Mul(x, y)
            base.Mod(base, Pow256)
            // Pop result back on the stack
            bm.stack.Push(base)
        case oDIV:
            x, y := bm.stack.Popn()
            // floor(x / y)
            base.Div(x, y)
            // Pop result back on the stack
            bm.stack.Push(base)
        case oSDIV:
            x, y := bm.stack.Popn()
            // n > 2**255
            if x.Cmp(Pow256) > 0 {
                x.Sub(Pow256, x)
            }
            if y.Cmp(Pow256) > 0 {
                y.Sub(Pow256, y)
            }
            z := new(big.Int)
            z.Div(x, y)
            if z.Cmp(Pow256) > 0 {
                z.Sub(Pow256, z)
            }
            // Push result on to the stack
            bm.stack.Push(z)
        case oMOD:
            x, y := bm.stack.Popn()
            base.Mod(x, y)
            bm.stack.Push(base)
        case oSMOD:
            x, y := bm.stack.Popn()
            // n > 2**255
            if x.Cmp(Pow256) > 0 {
                x.Sub(Pow256, x)
            }
            if y.Cmp(Pow256) > 0 {
                y.Sub(Pow256, y)
            }
            z := new(big.Int)
            z.Mod(x, y)
            if z.Cmp(Pow256) > 0 {
                z.Sub(Pow256, z)
            }
            // Push result on to the stack
            bm.stack.Push(z)
        case oEXP:
            x, y := bm.stack.Popn()
            base.Exp(x, y, Pow256)

            bm.stack.Push(base)
        case oNEG:
            base.Sub(Pow256, bm.stack.Pop())
            bm.stack.Push(base)
        case oLT:
            x, y := bm.stack.Popn()
            // x < y
            if x.Cmp(y) < 0 {
                bm.stack.Push(ethutil.BigTrue)
            } else {
                bm.stack.Push(ethutil.BigFalse)
            }
        case oLE:
            x, y := bm.stack.Popn()
            // x <= y
            if x.Cmp(y) < 1 {
                bm.stack.Push(ethutil.BigTrue)
            } else {
                bm.stack.Push(ethutil.BigFalse)
            }
        case oGT:
            x, y := bm.stack.Popn()
            // x > y
            if x.Cmp(y) > 0 {
                bm.stack.Push(ethutil.BigTrue)
            } else {
                bm.stack.Push(ethutil.BigFalse)
            }
        case oGE:
            x, y := bm.stack.Popn()
            // x >= y
            if x.Cmp(y) > -1 {
                bm.stack.Push(ethutil.BigTrue)
            } else {
                bm.stack.Push(ethutil.BigFalse)
            }
        case oNOT:
            x, y := bm.stack.Popn()
            // x != y
            if x.Cmp(y) != 0 {
                bm.stack.Push(ethutil.BigTrue)
            } else {
                bm.stack.Push(ethutil.BigFalse)
            }

        // Please note  that the  following code contains some
        // ugly string casting. This will have to change to big
        // ints. TODO :)
        case oMYADDRESS:
            bm.stack.Push(ethutil.BigD(tx.Hash()))
        case oTXSENDER:
            bm.stack.Push(ethutil.BigD(tx.Sender()))
        case oTXVALUE:
            bm.stack.Push(tx.Value)
        case oTXDATAN:
            bm.stack.Push(big.NewInt(int64(len(tx.Data))))
        case oTXDATA:
            v := bm.stack.Pop()
            // v >= len(data)
            if v.Cmp(big.NewInt(int64(len(tx.Data)))) >= 0 {
                bm.stack.Push(ethutil.Big("0"))
            } else {
                bm.stack.Push(ethutil.Big(tx.Data[v.Uint64()]))
            }
        case oBLK_PREVHASH:
            bm.stack.Push(ethutil.BigD(block.PrevHash))
        case oBLK_COINBASE:
            bm.stack.Push(ethutil.BigD(block.Coinbase))
        case oBLK_TIMESTAMP:
            bm.stack.Push(big.NewInt(block.Time))
        case oBLK_NUMBER:
            bm.stack.Push(big.NewInt(int64(blockInfo.Number)))
        case oBLK_DIFFICULTY:
            bm.stack.Push(block.Difficulty)
        case oBASEFEE:
            // e = 10^21
            e := big.NewInt(0).Exp(big.NewInt(10), big.NewInt(21), big.NewInt(0))
            d := new(big.Rat)
            d.SetInt(block.Difficulty)
            c := new(big.Rat)
            c.SetFloat64(0.5)
            // d = diff / 0.5
            d.Quo(d, c)
            // base = floor(d)
            base.Div(d.Num(), d.Denom())

            x := new(big.Int)
            x.Div(e, base)

            // x = floor(10^21 / floor(diff^0.5))
            bm.stack.Push(x)
        case oSHA256, oSHA3, oRIPEMD160:
            // This is probably save
            // ceil(pop / 32)
            length := int(math.Ceil(float64(bm.stack.Pop().Uint64()) / 32.0))
            // New buffer which will contain the concatenated popped items
            data := new(bytes.Buffer)
            for i := 0; i < length; i++ {
                // Encode the number to bytes and have it 32bytes long
                num := ethutil.NumberToBytes(bm.stack.Pop().Bytes(), 256)
                data.WriteString(string(num))
            }

            if op == oSHA256 {
                bm.stack.Push(base.SetBytes(ethutil.Sha256Bin(data.Bytes())))
            } else if op == oSHA3 {
                bm.stack.Push(base.SetBytes(ethutil.Sha3Bin(data.Bytes())))
            } else {
                bm.stack.Push(base.SetBytes(ethutil.Ripemd160(data.Bytes())))
            }
        case oECMUL:
            y := bm.stack.Pop()
            x := bm.stack.Pop()
            //n := bm.stack.Pop()

            //if ethutil.Big(x).Cmp(ethutil.Big(y)) {
            data := new(bytes.Buffer)
            data.WriteString(x.String())
            data.WriteString(y.String())
            if secp256k1.VerifyPubkeyValidity(data.Bytes()) == 1 {
                // TODO
            } else {
                // Invalid, push infinity
                bm.stack.Push(ethutil.Big("0"))
                bm.stack.Push(ethutil.Big("0"))
            }
            //} else {
            //  // Invalid, push infinity
            //  bm.stack.Push("0")
            //  bm.stack.Push("0")
            //}

        case oECADD:
        case oECSIGN:
        case oECRECOVER:
        case oECVALID:
        case oPUSH:
            pc++
            bm.stack.Push(bm.mem[strconv.Itoa(pc)])
        case oPOP:
            // Pop current value of the stack
            bm.stack.Pop()
        case oDUP:
            // Dup top stack
            x := bm.stack.Pop()
            bm.stack.Push(x)
            bm.stack.Push(x)
        case oSWAP:
            // Swap two top most values
            x, y := bm.stack.Popn()
            bm.stack.Push(y)
            bm.stack.Push(x)
        case oMLOAD:
            x := bm.stack.Pop()
            bm.stack.Push(bm.mem[x.String()])
        case oMSTORE:
            x, y := bm.stack.Popn()
            bm.mem[x.String()] = y
        case oSLOAD:
            // Load the value in storage and push it on the stack
            x := bm.stack.Pop()
            // decode the object as a big integer
            decoder := ethutil.NewValueFromBytes([]byte(contract.State().Get(x.String())))
            if !decoder.IsNil() {
                bm.stack.Push(decoder.BigInt())
            } else {
                bm.stack.Push(ethutil.BigFalse)
            }
        case oSSTORE:
            // Store Y at index X
            x, y := bm.stack.Popn()
            contract.State().Update(x.String(), string(ethutil.Encode(y)))
        case oJMP:
            x := int(bm.stack.Pop().Uint64())
            // Set pc to x - 1 (minus one so the incrementing at the end won't effect it)
            pc = x
            pc--
        case oJMPI:
            x := bm.stack.Pop()
            // Set pc to x if it's non zero
            if x.Cmp(ethutil.BigFalse) != 0 {
                pc = int(x.Uint64())
                pc--
            }
        case oIND:
            bm.stack.Push(big.NewInt(int64(pc)))
        case oEXTRO:
            memAddr := bm.stack.Pop()
            contractAddr := bm.stack.Pop().Bytes()

            // Push the contract's memory on to the stack
            bm.stack.Push(getContractMemory(block, contractAddr, memAddr))
        case oBALANCE:
            // Pushes the balance of the popped value on to the stack
            d := block.State().Get(bm.stack.Pop().String())
            ether := NewAddressFromData([]byte(d))
            bm.stack.Push(ether.Amount)
        case oMKTX:
            value, addr := bm.stack.Popn()
            from, length := bm.stack.Popn()

            j := 0
            dataItems := make([]string, int(length.Uint64()))
            for i := from.Uint64(); i < length.Uint64(); i++ {
                dataItems[j] = string(bm.mem[strconv.Itoa(int(i))].Bytes())
                j++
            }
            // TODO sign it?
            tx := NewTransaction(addr.Bytes(), value, dataItems)
            // Add the transaction to the tx pool
            bm.TransactionPool.QueueTransaction(tx)
        case oSUICIDE:
            //addr := bm.stack.Pop()
        }
        pc++
    }
}

// Returns an address from the specified contract's address
func getContractMemory(block *Block, contractAddr []byte, memAddr *big.Int) *big.Int {
    contract := block.GetContract(contractAddr)
    if contract == nil {
        log.Panicf("invalid contract addr %x", contractAddr)
    }
    val := contract.State().Get(memAddr.String())

    // decode the object as a big integer
    decoder := ethutil.NewValueFromBytes([]byte(val))
    if decoder.IsNil() {
        return ethutil.BigFalse
    }

    return decoder.BigInt()
}