func merkleRoot(data [][]byte) (types.Hash, error) {
if len(data) == 1 { // FIXME: a workaround for trees with one element
data = append(data, []byte{})
}
tree := merkle.NewTree()
err := tree.Generate(data, fastsha256.New())
if err != nil {
return types.EmptyHash(), err
}
return types.NewHash(tree.Root().Hash), err
}
func listener() {
var msg transaction.T
var blk *block.Block
blockChannel := make(chan *block.Block)
var transactionsPool []transaction.T
var previousBlockHash types.Hash
miningEmpty := false
initPool:
transactionsPool = make([]transaction.T, 0)
loop:
select {
case msg = <-ch:
miningEmpty = false
env.DB.PutTransaction(msg)
transactionsPool = append(transactionsPool, msg)
if blk, _ = env.DB.GetLastBlock(); blk == nil {
previousBlockHash = types.EmptyHash()
} else {
previousBlockHash = types.NewHash(blk.Hash())
}
if bat := prepareBAT(); bat != nil {
transactionsPool = append(transactionsPool, bat)
}
blk, err := block.NewBlock(previousBlockHash, targetBits(), transactionsPool)
if err != nil {
log.Printf("Error while creating a new block: %v", err)
} else {
miningFactoryRequests <- MiningFactoryInstantiationRequest{Block: blk, ResponseChannel: blockChannel}
}
case blk = <-blockChannel:
miningEmpty = false
if lastBlk, _ := env.DB.GetLastBlock(); lastBlk == nil {
previousBlockHash = types.EmptyHash()
} else {
previousBlockHash = types.NewHash(blk.Hash())
}
isLastBlock := bytes.Compare(blk.PreviousBlockHash[:], previousBlockHash[:]) == 0
env.DB.PutBlock(blk, isLastBlock)
goto initPool
default:
if len(transactionsPool) == 0 && !miningEmpty {
// if there are no transactions to be included into a block, try mining an empty/BAT-only block
if blk, _ = env.DB.GetLastBlock(); blk == nil {
previousBlockHash = types.EmptyHash()
} else {
previousBlockHash = types.NewHash(blk.Hash())
}
if bat := prepareBAT(); bat != nil {
transactionsPool = append(transactionsPool, bat)
}
blk, err := block.NewBlock(previousBlockHash, targetBits(), transactionsPool)
if err != nil {
log.Printf("Error while creating a new block: %v", err)
} else {
miningFactoryRequests <- MiningFactoryInstantiationRequest{Block: blk, ResponseChannel: blockChannel}
miningEmpty = true
}
}
}
goto loop
}