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|
package main
import (
"errors"
"fmt"
"github.com/ethereum/ethutil-go"
"log"
"math/big"
)
type BlockChain struct {
LastBlock *ethutil.Block
genesisBlock *ethutil.Block
TD *big.Int
}
func NewBlockChain() *BlockChain {
bc := &BlockChain{}
bc.genesisBlock = ethutil.NewBlock(ethutil.Encode(ethutil.Genesis))
// Set the last know difficulty (might be 0x0 as initial value, Genesis)
bc.TD = new(big.Int)
bc.TD.SetBytes(ethutil.Config.Db.LastKnownTD())
// TODO get last block from the database
//bc.LastBlock = bc.genesisBlock
return bc
}
func (bc *BlockChain) HasBlock(hash string) bool {
data, _ := ethutil.Config.Db.Get([]byte(hash))
return len(data) != 0
}
func (bc *BlockChain) GenesisBlock() *ethutil.Block {
return bc.genesisBlock
}
type BlockManager struct {
// Ethereum virtual machine for processing contracts
vm *Vm
// The block chain :)
bc *BlockChain
}
func NewBlockManager() *BlockManager {
bm := &BlockManager{
vm: NewVm(),
bc: NewBlockChain(),
}
return bm
}
// Process a block.
func (bm *BlockManager) ProcessBlock(block *ethutil.Block) error {
// 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(block); err != nil {
return err
}
// Get the tx count. Used to create enough channels to 'join' the go routines
txCount := len(block.Transactions())
// Locking channel. When it has been fully buffered this method will return
lockChan := make(chan bool, txCount)
// Process each transaction/contract
for _, tx := range block.Transactions() {
// If there's no recipient, it's a contract
if tx.IsContract() {
go bm.ProcessContract(tx, block, lockChan)
} else {
// "finish" tx which isn't a contract
lockChan <- true
}
}
// Wait for all Tx to finish processing
for i := 0; i < txCount; i++ {
<-lockChan
}
if bm.CalculateTD(block) {
ethutil.Config.Db.Put(block.Hash(), block.MarshalRlp())
bm.bc.LastBlock = block
}
return nil
}
func (bm *BlockManager) CalculateTD(block *ethutil.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 {
bm.bc.LastBlock = block
// Set the new total difficulty back to the block chain
bm.bc.TD = td
if Debug {
log.Println("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 *ethutil.Block) error {
// TODO
// 2. Check if the difficulty is correct
// 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.LastBlock != nil && block.PrevHash == "" &&
!bm.bc.HasBlock(block.PrevHash) {
return errors.New("Block's parent unknown")
}
// Check each uncle's previous hash. In order for it to be valid
// is if it has the same block hash as the current
for _, uncle := range block.Uncles {
if uncle.PrevHash != block.PrevHash {
if Debug {
log.Printf("Uncle prvhash mismatch %x %x\n", block.PrevHash, uncle.PrevHash)
}
return errors.New("Mismatching Prvhash from uncle")
}
}
// Verify the nonce of the block. Return an error if it's not valid
if bm.bc.LastBlock != nil && block.PrevHash == "" &&
!DaggerVerify(ethutil.BigD(block.Hash()), block.Difficulty, block.Nonce) {
return errors.New("Block's nonce is invalid")
}
log.Println("Block validation PASSED")
return nil
}
func (bm *BlockManager) AccumelateRewards(block *ethutil.Block) error {
// Get the coinbase rlp data
d := block.State().Get(block.Coinbase)
ether := ethutil.NewEtherFromData([]byte(d))
// Reward amount of ether to the coinbase address
ether.AddFee(ethutil.CalculateBlockReward(block, len(block.Uncles)))
block.State().Update(block.Coinbase, string(ether.MarshalRlp()))
// TODO Reward each uncle
return nil
}
func (bm *BlockManager) ProcessContract(tx *ethutil.Transaction, block *ethutil.Block, lockChan chan bool) {
// 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)
// Let the channel know where done even though it failed (so the execution may resume normally)
lockChan <- true
}
}()
// Process contract
bm.vm.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
})
// Broadcast we're done
lockChan <- true
}
|
