Merge branch 'master' into develop

12 files changed, 282 insertions, 133 deletions

diff --git a/ethchain/address.go b/ethchain/address.go
index a228c7566..aa1709f2c 100644
--- a/ethchain/address.go
+++ b/ethchain/address.go
@@ -5,31 +5,31 @@ import (
 	"math/big"
 )
 
-type Address struct {
+type Account struct {
 	Amount *big.Int
 	Nonce  uint64
 }
 
-func NewAddress(amount *big.Int) *Address {
-	return &Address{Amount: amount, Nonce: 0}
+func NewAccount(amount *big.Int) *Account {
+	return &Account{Amount: amount, Nonce: 0}
 }
 
-func NewAddressFromData(data []byte) *Address {
-	address := &Address{}
+func NewAccountFromData(data []byte) *Account {
+	address := &Account{}
 	address.RlpDecode(data)
 
 	return address
 }
 
-func (a *Address) AddFee(fee *big.Int) {
+func (a *Account) AddFee(fee *big.Int) {
 	a.Amount.Add(a.Amount, fee)
 }
 
-func (a *Address) RlpEncode() []byte {
+func (a *Account) RlpEncode() []byte {
 	return ethutil.Encode([]interface{}{a.Amount, a.Nonce})
 }
 
-func (a *Address) RlpDecode(data []byte) {
+func (a *Account) RlpDecode(data []byte) {
 	decoder := ethutil.NewValueFromBytes(data)
 
 	a.Amount = decoder.Get(0).BigInt()
@@ -37,24 +37,24 @@ func (a *Address) RlpDecode(data []byte) {
 }
 
 type AddrStateStore struct {
-	states map[string]*AddressState
+	states map[string]*AccountState
 }
 
 func NewAddrStateStore() *AddrStateStore {
-	return &AddrStateStore{states: make(map[string]*AddressState)}
+	return &AddrStateStore{states: make(map[string]*AccountState)}
 }
 
-func (s *AddrStateStore) Add(addr []byte, account *Address) *AddressState {
-	state := &AddressState{Nonce: account.Nonce, Account: account}
+func (s *AddrStateStore) Add(addr []byte, account *Account) *AccountState {
+	state := &AccountState{Nonce: account.Nonce, Account: account}
 	s.states[string(addr)] = state
 	return state
 }
 
-func (s *AddrStateStore) Get(addr []byte) *AddressState {
+func (s *AddrStateStore) Get(addr []byte) *AccountState {
 	return s.states[string(addr)]
 }
 
-type AddressState struct {
+type AccountState struct {
 	Nonce   uint64
-	Account *Address
+	Account *Account
 }
diff --git a/ethchain/block.go b/ethchain/block.go
index 7ca44a47d..20af73ba2 100644
--- a/ethchain/block.go
+++ b/ethchain/block.go
@@ -34,7 +34,8 @@ type Block struct {
 	// The coin base address
 	Coinbase []byte
 	// Block Trie state
-	state *ethutil.Trie
+	//state *ethutil.Trie
+	state *State
 	// Difficulty for the current block
 	Difficulty *big.Int
 	// Creation time
@@ -94,7 +95,7 @@ func CreateBlock(root interface{},
 	block.SetTransactions(txes)
 	block.SetUncles([]*Block{})
 
-	block.state = ethutil.NewTrie(ethutil.Config.Db, root)
+	block.state = NewState(ethutil.NewTrie(ethutil.Config.Db, root))
 
 	for _, tx := range txes {
 		block.MakeContract(tx)
@@ -109,15 +110,15 @@ func (block *Block) Hash() []byte {
 }
 
 func (block *Block) HashNoNonce() []byte {
-	return ethutil.Sha3Bin(ethutil.Encode([]interface{}{block.PrevHash, block.UncleSha, block.Coinbase, block.state.Root, block.TxSha, block.Difficulty, block.Time, block.Extra}))
+	return ethutil.Sha3Bin(ethutil.Encode([]interface{}{block.PrevHash, block.UncleSha, block.Coinbase, block.state.trie.Root, block.TxSha, block.Difficulty, block.Time, block.Extra}))
 }
 
 func (block *Block) PrintHash() {
 	fmt.Println(block)
-	fmt.Println(ethutil.NewValue(ethutil.Encode([]interface{}{block.PrevHash, block.UncleSha, block.Coinbase, block.state.Root, block.TxSha, block.Difficulty, block.Time, block.Extra, block.Nonce})))
+	fmt.Println(ethutil.NewValue(ethutil.Encode([]interface{}{block.PrevHash, block.UncleSha, block.Coinbase, block.state.trie.Root, block.TxSha, block.Difficulty, block.Time, block.Extra, block.Nonce})))
 }
 
-func (block *Block) State() *ethutil.Trie {
+func (block *Block) State() *State {
 	return block.state
 }
 
@@ -125,54 +126,8 @@ func (block *Block) Transactions() []*Transaction {
 	return block.transactions
 }
 
-func (block *Block) GetContract(addr []byte) *Contract {
-	data := block.state.Get(string(addr))
-	if data == "" {
-		return nil
-	}
-
-	value := ethutil.NewValueFromBytes([]byte(data))
-	if value.Len() == 2 {
-		return nil
-	}
-
-	contract := &Contract{}
-	contract.RlpDecode([]byte(data))
-
-	cachedState := block.contractStates[string(addr)]
-	if cachedState != nil {
-		contract.state = cachedState
-	} else {
-		block.contractStates[string(addr)] = contract.state
-	}
-
-	return contract
-}
-func (block *Block) UpdateContract(addr []byte, contract *Contract) {
-	// Make sure the state is synced
-	//contract.State().Sync()
-
-	block.state.Update(string(addr), string(contract.RlpEncode()))
-}
-
-func (block *Block) GetAddr(addr []byte) *Address {
-	var address *Address
-
-	data := block.State().Get(string(addr))
-	if data == "" {
-		address = NewAddress(big.NewInt(0))
-	} else {
-		address = NewAddressFromData([]byte(data))
-	}
-
-	return address
-}
-func (block *Block) UpdateAddr(addr []byte, address *Address) {
-	block.state.Update(string(addr), string(address.RlpEncode()))
-}
-
 func (block *Block) PayFee(addr []byte, fee *big.Int) bool {
-	contract := block.GetContract(addr)
+	contract := block.state.GetContract(addr)
 	// If we can't pay the fee return
 	if contract == nil || contract.Amount.Cmp(fee) < 0 /* amount < fee */ {
 		fmt.Println("Contract has insufficient funds", contract.Amount, fee)
@@ -182,17 +137,17 @@ func (block *Block) PayFee(addr []byte, fee *big.Int) bool {
 
 	base := new(big.Int)
 	contract.Amount = base.Sub(contract.Amount, fee)
-	block.state.Update(string(addr), string(contract.RlpEncode()))
+	block.state.trie.Update(string(addr), string(contract.RlpEncode()))
 
-	data := block.state.Get(string(block.Coinbase))
+	data := block.state.trie.Get(string(block.Coinbase))
 
 	// Get the ether (Coinbase) and add the fee (gief fee to miner)
-	ether := NewAddressFromData([]byte(data))
+	ether := NewAccountFromData([]byte(data))
 
 	base = new(big.Int)
 	ether.Amount = base.Add(ether.Amount, fee)
 
-	block.state.Update(string(block.Coinbase), string(ether.RlpEncode()))
+	block.state.trie.Update(string(block.Coinbase), string(ether.RlpEncode()))
 
 	return true
 }
@@ -207,27 +162,18 @@ func (block *Block) BlockInfo() BlockInfo {
 
 // Sync the block's state and contract respectively
 func (block *Block) Sync() {
-	// Sync all contracts currently in cache
-	for _, val := range block.contractStates {
-		val.Sync()
-	}
-	// Sync the block state itself
 	block.state.Sync()
 }
 
 func (block *Block) Undo() {
-	// Sync all contracts currently in cache
-	for _, val := range block.contractStates {
-		val.Undo()
-	}
 	// Sync the block state itself
-	block.state.Undo()
+	block.state.Reset()
 }
 
 func (block *Block) MakeContract(tx *Transaction) {
-	contract := MakeContract(tx, NewState(block.state))
+	contract := MakeContract(tx, block.state)
 	if contract != nil {
-		block.contractStates[string(tx.Hash()[12:])] = contract.state
+		block.state.states[string(tx.Hash()[12:])] = contract.state
 	}
 }
 
@@ -308,7 +254,7 @@ func (block *Block) RlpValueDecode(decoder *ethutil.Value) {
 	block.PrevHash = header.Get(0).Bytes()
 	block.UncleSha = header.Get(1).Bytes()
 	block.Coinbase = header.Get(2).Bytes()
-	block.state = ethutil.NewTrie(ethutil.Config.Db, header.Get(3).Val)
+	block.state = NewState(ethutil.NewTrie(ethutil.Config.Db, header.Get(3).Val))
 	block.TxSha = header.Get(4).Bytes()
 	block.Difficulty = header.Get(5).BigInt()
 	block.Time = int64(header.Get(6).BigInt().Uint64())
@@ -345,7 +291,7 @@ func NewUncleBlockFromValue(header *ethutil.Value) *Block {
 	block.PrevHash = header.Get(0).Bytes()
 	block.UncleSha = header.Get(1).Bytes()
 	block.Coinbase = header.Get(2).Bytes()
-	block.state = ethutil.NewTrie(ethutil.Config.Db, header.Get(3).Val)
+	block.state = NewState(ethutil.NewTrie(ethutil.Config.Db, header.Get(3).Val))
 	block.TxSha = header.Get(4).Bytes()
 	block.Difficulty = header.Get(5).BigInt()
 	block.Time = int64(header.Get(6).BigInt().Uint64())
@@ -356,7 +302,7 @@ func NewUncleBlockFromValue(header *ethutil.Value) *Block {
 }
 
 func (block *Block) String() string {
-	return fmt.Sprintf("Block(%x):\nPrevHash:%x\nUncleSha:%x\nCoinbase:%x\nRoot:%x\nTxSha:%x\nDiff:%v\nTime:%d\nNonce:%x\nTxs:%d\n", block.Hash(), block.PrevHash, block.UncleSha, block.Coinbase, block.state.Root, block.TxSha, block.Difficulty, block.Time, block.Nonce, len(block.transactions))
+	return fmt.Sprintf("Block(%x):\nPrevHash:%x\nUncleSha:%x\nCoinbase:%x\nRoot:%x\nTxSha:%x\nDiff:%v\nTime:%d\nNonce:%x\nTxs:%d\n", block.Hash(), block.PrevHash, block.UncleSha, block.Coinbase, block.state.trie.Root, block.TxSha, block.Difficulty, block.Time, block.Nonce, len(block.transactions))
 }
 
 //////////// UNEXPORTED /////////////////
@@ -369,7 +315,7 @@ func (block *Block) header() []interface{} {
 		// Coinbase address
 		block.Coinbase,
 		// root state
-		block.state.Root,
+		block.state.trie.Root,
 		// Sha of tx
 		block.TxSha,
 		// Current block Difficulty
diff --git a/ethchain/block_chain.go b/ethchain/block_chain.go
index 96d22366d..026fc1cea 100644
--- a/ethchain/block_chain.go
+++ b/ethchain/block_chain.go
@@ -39,7 +39,7 @@ func (bc *BlockChain) NewBlock(coinbase []byte, txs []*Transaction) *Block {
 	hash := ZeroHash256
 
 	if bc.CurrentBlock != nil {
-		root = bc.CurrentBlock.State().Root
+		root = bc.CurrentBlock.state.trie.Root
 		hash = bc.LastBlockHash
 		lastBlockTime = bc.CurrentBlock.Time
 	}
diff --git a/ethchain/block_manager.go b/ethchain/block_manager.go
index 364a06158..b184fa9c9 100644
--- a/ethchain/block_manager.go
+++ b/ethchain/block_manager.go
@@ -51,9 +51,9 @@ func AddTestNetFunds(block *Block) {
 	} {
 		//log.Println("2^200 Wei to", addr)
 		codedAddr, _ := hex.DecodeString(addr)
-		addr := block.GetAddr(codedAddr)
+		addr := block.state.GetAccount(codedAddr)
 		addr.Amount = ethutil.BigPow(2, 200)
-		block.UpdateAddr(codedAddr, addr)
+		block.state.UpdateAccount(codedAddr, addr)
 	}
 }
 
@@ -71,7 +71,7 @@ func NewBlockManager(speaker PublicSpeaker) *BlockManager {
 	if bm.bc.CurrentBlock == nil {
 		AddTestNetFunds(bm.bc.genesisBlock)
 
-		bm.bc.genesisBlock.State().Sync()
+		bm.bc.genesisBlock.state.trie.Sync()
 		// Prepare the genesis block
 		bm.bc.Add(bm.bc.genesisBlock)
 
@@ -85,17 +85,17 @@ func NewBlockManager(speaker PublicSpeaker) *BlockManager {
 }
 
 // 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)
+func (bm *BlockManager) WatchAddr(addr []byte) *AccountState {
+	account := bm.bc.CurrentBlock.state.GetAccount(addr)
 
 	return bm.addrStateStore.Add(addr, account)
 }
 
-func (bm *BlockManager) GetAddrState(addr []byte) *AddressState {
+func (bm *BlockManager) GetAddrState(addr []byte) *AccountState {
 	account := bm.addrStateStore.Get(addr)
 	if account == nil {
-		a := bm.bc.CurrentBlock.GetAddr(addr)
-		account = &AddressState{Nonce: a.Nonce, Account: a}
+		a := bm.bc.CurrentBlock.state.GetAccount(addr)
+		account = &AccountState{Nonce: a.Nonce, Account: a}
 	}
 
 	return account
@@ -112,7 +112,7 @@ func (bm *BlockManager) ApplyTransactions(block *Block, txs []*Transaction) {
 		if tx.IsContract() {
 			block.MakeContract(tx)
 		} else {
-			if contract := block.GetContract(tx.Recipient); contract != nil {
+			if contract := block.state.GetContract(tx.Recipient); contract != nil {
 				bm.ProcessContract(contract, tx, block)
 			} else {
 				err := bm.TransactionPool.ProcessTransaction(tx, block)
@@ -161,8 +161,8 @@ func (bm *BlockManager) ProcessBlock(block *Block) error {
 		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)
+	if !block.state.Cmp(bm.bc.CurrentBlock.state) {
+		return fmt.Errorf("Invalid merkle root. Expected %x, got %x", block.State().trie.Root, bm.bc.CurrentBlock.State().trie.Root)
 	}
 
 	// Calculate the new total difficulty and sync back to the db
@@ -267,17 +267,17 @@ func CalculateUncleReward(block *Block) *big.Int {
 
 func (bm *BlockManager) AccumelateRewards(processor *Block, block *Block) error {
 	// Get the coinbase rlp data
-	addr := processor.GetAddr(block.Coinbase)
+	addr := processor.state.GetAccount(block.Coinbase)
 	// Reward amount of ether to the coinbase address
 	addr.AddFee(CalculateBlockReward(block, len(block.Uncles)))
 
-	processor.UpdateAddr(block.Coinbase, addr)
+	processor.state.UpdateAccount(block.Coinbase, addr)
 
 	for _, uncle := range block.Uncles {
-		uncleAddr := processor.GetAddr(uncle.Coinbase)
+		uncleAddr := processor.state.GetAccount(uncle.Coinbase)
 		uncleAddr.AddFee(CalculateUncleReward(uncle))
 
-		processor.UpdateAddr(uncle.Coinbase, uncleAddr)
+		processor.state.UpdateAccount(uncle.Coinbase, uncleAddr)
 	}
 
 	return nil
@@ -298,7 +298,7 @@ func (bm *BlockManager) ProcessContract(contract *Contract, tx *Transaction, blo
 	*/
 
 	vm := &Vm{}
-	vm.Process(contract, NewState(block.state), RuntimeVars{
+	vm.Process(contract, block.state, RuntimeVars{
 		address:     tx.Hash()[12:],
 		blockNumber: block.BlockInfo().Number,
 		sender:      tx.Sender(),
diff --git a/ethchain/contract.go b/ethchain/contract.go
index dbcbb3697..21ac828fe 100644
--- a/ethchain/contract.go
+++ b/ethchain/contract.go
@@ -8,18 +8,19 @@ import (
 type Contract struct {
 	Amount *big.Int
 	Nonce  uint64
-	state  *ethutil.Trie
+	//state  *ethutil.Trie
+	state *State
 }
 
 func NewContract(Amount *big.Int, root []byte) *Contract {
 	contract := &Contract{Amount: Amount, Nonce: 0}
-	contract.state = ethutil.NewTrie(ethutil.Config.Db, string(root))
+	contract.state = NewState(ethutil.NewTrie(ethutil.Config.Db, string(root)))
 
 	return contract
 }
 
 func (c *Contract) RlpEncode() []byte {
-	return ethutil.Encode([]interface{}{c.Amount, c.Nonce, c.state.Root})
+	return ethutil.Encode([]interface{}{c.Amount, c.Nonce, c.state.trie.Root})
 }
 
 func (c *Contract) RlpDecode(data []byte) {
@@ -27,18 +28,18 @@ func (c *Contract) RlpDecode(data []byte) {
 
 	c.Amount = decoder.Get(0).BigInt()
 	c.Nonce = decoder.Get(1).Uint()
-	c.state = ethutil.NewTrie(ethutil.Config.Db, decoder.Get(2).Interface())
+	c.state = NewState(ethutil.NewTrie(ethutil.Config.Db, decoder.Get(2).Interface()))
 }
 
 func (c *Contract) Addr(addr []byte) *ethutil.Value {
-	return ethutil.NewValueFromBytes([]byte(c.state.Get(string(addr))))
+	return ethutil.NewValueFromBytes([]byte(c.state.trie.Get(string(addr))))
 }
 
 func (c *Contract) SetAddr(addr []byte, value interface{}) {
-	c.state.Update(string(addr), string(ethutil.NewValue(value).Encode()))
+	c.state.trie.Update(string(addr), string(ethutil.NewValue(value).Encode()))
 }
 
-func (c *Contract) State() *ethutil.Trie {
+func (c *Contract) State() *State {
 	return c.state
 }
 
@@ -59,7 +60,7 @@ func MakeContract(tx *Transaction, state *State) *Contract {
 		for i, val := range tx.Data {
 			if len(val) > 0 {
 				bytNum := ethutil.BigToBytes(big.NewInt(int64(i)), 256)
-				contract.state.Update(string(bytNum), string(ethutil.Encode(val)))
+				contract.state.trie.Update(string(bytNum), string(ethutil.Encode(val)))
 			}
 		}
 		state.trie.Update(string(addr), string(contract.RlpEncode()))
diff --git a/ethchain/state.go b/ethchain/state.go
index 1a18ea1d7..e6649cf22 100644
--- a/ethchain/state.go
+++ b/ethchain/state.go
@@ -5,12 +5,46 @@ import (
 	"math/big"
 )
 
+// States within the ethereum protocol are used to store anything
+// within the merkle trie. States take care of caching and storing
+// nested states. It's the general query interface to retrieve:
+// * Contracts
+// * Accounts
 type State struct {
+	// The trie for this structure
 	trie *ethutil.Trie
+	// Nested states
+	states map[string]*State
 }
 
+// Create a new state from a given trie
 func NewState(trie *ethutil.Trie) *State {
-	return &State{trie: trie}
+	return &State{trie: trie, states: make(map[string]*State)}
+}
+
+// Resets the trie and all siblings
+func (s *State) Reset() {
+	s.trie.Undo()
+
+	// Reset all nested states
+	for _, state := range s.states {
+		state.Reset()
+	}
+}
+
+// Syncs the trie and all siblings
+func (s *State) Sync() {
+	s.trie.Sync()
+
+	// Sync all nested states
+	for _, state := range s.states {
+		state.Sync()
+	}
+}
+
+// Purges the current trie.
+func (s *State) Purge() int {
+	return s.trie.NewIterator().Purge()
 }
 
 func (s *State) GetContract(addr []byte) *Contract {
@@ -19,9 +53,28 @@ func (s *State) GetContract(addr []byte) *Contract {
 		return nil
 	}
 
+	// Whet get contract is called the retrieved value might
+	// be an account. The StateManager uses this to check
+	// to see if the address a tx was sent to is a contract
+	// or an account
+	value := ethutil.NewValueFromBytes([]byte(data))
+	if value.Len() == 2 {
+		return nil
+	}
+
+	// build contract
 	contract := &Contract{}
 	contract.RlpDecode([]byte(data))
 
+	// Check if there's a cached state for this contract
+	cachedState := s.states[string(addr)]
+	if cachedState != nil {
+		contract.state = cachedState
+	} else {
+		// If it isn't cached, cache the state
+		s.states[string(addr)] = contract.state
+	}
+
 	return contract
 }
 
@@ -40,17 +93,21 @@ func Compile(code []string) (script []string) {
 	return
 }
 
-func (s *State) GetAccount(addr []byte) (account *Address) {
+func (s *State) GetAccount(addr []byte) (account *Account) {
 	data := s.trie.Get(string(addr))
 	if data == "" {
-		account = NewAddress(big.NewInt(0))
+		account = NewAccount(big.NewInt(0))
 	} else {
-		account = NewAddressFromData([]byte(data))
+		account = NewAccountFromData([]byte(data))
 	}
 
 	return
 }
 
-func (s *State) UpdateAccount(addr []byte, account *Address) {
+func (s *State) UpdateAccount(addr []byte, account *Account) {
 	s.trie.Update(string(addr), string(account.RlpEncode()))
 }
+
+func (s *State) Cmp(other *State) bool {
+	return s.trie.Cmp(other.trie)
+}
diff --git a/ethchain/transaction_pool.go b/ethchain/transaction_pool.go
index cd09bf02e..763560570 100644
--- a/ethchain/transaction_pool.go
+++ b/ethchain/transaction_pool.go
@@ -104,7 +104,7 @@ func (pool *TxPool) ProcessTransaction(tx *Transaction, block *Block) (err error
 		}
 	}()
 	// Get the sender
-	sender := block.GetAddr(tx.Sender())
+	sender := block.state.GetAccount(tx.Sender())
 
 	// Make sure there's enough in the sender's account. Having insufficient
 	// funds won't invalidate this transaction but simple ignores it.
@@ -122,7 +122,7 @@ func (pool *TxPool) ProcessTransaction(tx *Transaction, block *Block) (err error
 	}
 
 	// Get the receiver
-	receiver := block.GetAddr(tx.Recipient)
+	receiver := block.state.GetAccount(tx.Recipient)
 	sender.Nonce += 1
 
 	// Send Tx to self
@@ -136,10 +136,10 @@ func (pool *TxPool) ProcessTransaction(tx *Transaction, block *Block) (err error
 		// Add the amount to receivers account which should conclude this transaction
 		receiver.Amount.Add(receiver.Amount, tx.Value)
 
-		block.UpdateAddr(tx.Recipient, receiver)
+		block.state.UpdateAccount(tx.Recipient, receiver)
 	}
 
-	block.UpdateAddr(tx.Sender(), sender)
+	block.state.UpdateAccount(tx.Sender(), sender)
 
 	log.Printf("[TXPL] Processed Tx %x\n", tx.Hash())
 
diff --git a/ethchain/vm.go b/ethchain/vm.go
index c7a91a9c5..7e119ac99 100644
--- a/ethchain/vm.go
+++ b/ethchain/vm.go
@@ -330,7 +330,7 @@ out:
 			// Load the value in storage and push it on the stack
 			x := vm.stack.Pop()
 			// decode the object as a big integer
-			decoder := ethutil.NewValueFromBytes([]byte(contract.State().Get(x.String())))
+			decoder := contract.Addr(x.Bytes())
 			if !decoder.IsNil() {
 				vm.stack.Push(decoder.BigInt())
 			} else {
@@ -375,7 +375,7 @@ out:
 		case oSUICIDE:
 			recAddr := vm.stack.Pop().Bytes()
 			// Purge all memory
-			deletedMemory := contract.state.NewIterator().Purge()
+			deletedMemory := contract.state.Purge()
 			// Add refunds to the pop'ed address
 			refund := new(big.Int).Mul(StoreFee, big.NewInt(int64(deletedMemory)))
 			account := state.GetAccount(recAddr)
diff --git a/ethutil/common_test.go b/ethutil/common_test.go
index 3a6a37ff5..b5c733ff3 100644
--- a/ethutil/common_test.go
+++ b/ethutil/common_test.go
@@ -1,17 +1,44 @@
 package ethutil
 
 import (
-	"fmt"
 	"math/big"
 	"testing"
 )
 
 func TestCommon(t *testing.T) {
-	fmt.Println(CurrencyToString(BigPow(10, 19)))
-	fmt.Println(CurrencyToString(BigPow(10, 16)))
-	fmt.Println(CurrencyToString(BigPow(10, 13)))
-	fmt.Println(CurrencyToString(BigPow(10, 10)))
-	fmt.Println(CurrencyToString(BigPow(10, 7)))
-	fmt.Println(CurrencyToString(BigPow(10, 4)))
-	fmt.Println(CurrencyToString(big.NewInt(10)))
+	ether := CurrencyToString(BigPow(10, 19))
+	finney := CurrencyToString(BigPow(10, 16))
+	szabo := CurrencyToString(BigPow(10, 13))
+	vito := CurrencyToString(BigPow(10, 10))
+	turing := CurrencyToString(BigPow(10, 7))
+	eins := CurrencyToString(BigPow(10, 4))
+	wei := CurrencyToString(big.NewInt(10))
+
+	if ether != "10 Ether" {
+		t.Error("Got", ether)
+	}
+
+	if finney != "10 Finney" {
+		t.Error("Got", finney)
+	}
+
+	if szabo != "10 Szabo" {
+		t.Error("Got", szabo)
+	}
+
+	if vito != "10 Vito" {
+		t.Error("Got", vito)
+	}
+
+	if turing != "10 Turing" {
+		t.Error("Got", turing)
+	}
+
+	if eins != "10 Eins" {
+		t.Error("Got", eins)
+	}
+
+	if wei != "10 Wei" {
+		t.Error("Got", wei)
+	}
 }
diff --git a/ethutil/reactor.go b/ethutil/reactor.go
new file mode 100644
index 000000000..f8084986c
--- /dev/null
+++ b/ethutil/reactor.go
@@ -0,0 +1,86 @@
+package ethutil
+
+import (
+	"sync"
+)
+
+type ReactorEvent struct {
+	mut   sync.Mutex
+	event string
+	chans []chan React
+}
+
+// Post the specified reactor resource on the channels
+// currently subscribed
+func (e *ReactorEvent) Post(react React) {
+	e.mut.Lock()
+	defer e.mut.Unlock()
+
+	for _, ch := range e.chans {
+		go func(ch chan React) {
+			ch <- react
+		}(ch)
+	}
+}
+
+// Add a subscriber to this event
+func (e *ReactorEvent) Add(ch chan React) {
+	e.mut.Lock()
+	defer e.mut.Unlock()
+
+	e.chans = append(e.chans, ch)
+}
+
+// Remove a subscriber
+func (e *ReactorEvent) Remove(ch chan React) {
+	e.mut.Lock()
+	defer e.mut.Unlock()
+
+	for i, c := range e.chans {
+		if c == ch {
+			e.chans = append(e.chans[:i], e.chans[i+1:]...)
+		}
+	}
+}
+
+// Basic reactor resource
+type React struct {
+	Resource interface{}
+}
+
+// The reactor basic engine. Acts as bridge
+// between the events and the subscribers/posters
+type ReactorEngine struct {
+	patterns map[string]*ReactorEvent
+}
+
+func NewReactorEngine() *ReactorEngine {
+	return &ReactorEngine{patterns: make(map[string]*ReactorEvent)}
+}
+
+// Subscribe a channel to the specified event
+func (reactor *ReactorEngine) Subscribe(event string, ch chan React) {
+	ev := reactor.patterns[event]
+	// Create a new event if one isn't available
+	if ev == nil {
+		ev = &ReactorEvent{event: event}
+		reactor.patterns[event] = ev
+	}
+
+	// Add the channel to reactor event handler
+	ev.Add(ch)
+}
+
+func (reactor *ReactorEngine) Unsubscribe(event string, ch chan React) {
+	ev := reactor.patterns[event]
+	if ev != nil {
+		ev.Remove(ch)
+	}
+}
+
+func (reactor *ReactorEngine) Post(event string, resource interface{}) {
+	ev := reactor.patterns[event]
+	if ev != nil {
+		ev.Post(React{Resource: resource})
+	}
+}
diff --git a/ethutil/reactor_test.go b/ethutil/reactor_test.go
new file mode 100644
index 000000000..48c2f0df3
--- /dev/null
+++ b/ethutil/reactor_test.go
@@ -0,0 +1,30 @@
+package ethutil
+
+import "testing"
+
+func TestReactorAdd(t *testing.T) {
+	engine := NewReactorEngine()
+	ch := make(chan React)
+	engine.Subscribe("test", ch)
+	if len(engine.patterns) != 1 {
+		t.Error("Expected patterns to be 1, got", len(engine.patterns))
+	}
+}
+
+func TestReactorEvent(t *testing.T) {
+	engine := NewReactorEngine()
+
+	// Buffer 1, so it doesn't block for this test
+	ch := make(chan React, 1)
+	engine.Subscribe("test", ch)
+	engine.Post("test", "hello")
+
+	value := <-ch
+	if val, ok := value.Resource.(string); ok {
+		if val != "hello" {
+			t.Error("Expected Resource to be 'hello', got", val)
+		}
+	} else {
+		t.Error("Unable to cast")
+	}
+}
diff --git a/peer.go b/peer.go
index 970619714..271c8708e 100644
--- a/peer.go
+++ b/peer.go
@@ -17,6 +17,8 @@ import (
 const (
 	// The size of the output buffer for writing messages
 	outputBufferSize = 50
+	// Current protocol version
+	ProtocolVersion = 7
 )
 
 type DiscReason byte
@@ -469,7 +471,7 @@ func (p *Peer) pushHandshake() error {
 	pubkey := ethutil.NewValueFromBytes(data).Get(2).Bytes()
 
 	msg := ethwire.NewMessage(ethwire.MsgHandshakeTy, []interface{}{
-		uint32(5), uint32(0), p.Version, byte(p.caps), p.port, pubkey,
+		uint32(ProtocolVersion), uint32(0), p.Version, byte(p.caps), p.port, pubkey,
 	})
 
 	p.QueueMessage(msg)
@@ -496,7 +498,7 @@ func (p *Peer) pushPeers() {
 func (p *Peer) handleHandshake(msg *ethwire.Msg) {
 	c := msg.Data
 
-	if c.Get(0).Uint() != 5 {
+	if c.Get(0).Uint() != ProtocolVersion {
 		ethutil.Config.Log.Debugln("Invalid peer version. Require protocol v5")
 		p.Stop()
 		return