// GetBalance returns the amount of wei for the given address in the state of the given block number.
// When block number equals rpc.LatestBlockNumber the current block is used.
func (s *PublicBlockChainAPI) GetBalance(address common.Address, blockNr rpc.BlockNumber) (*big.Int, error) {
block := blockByNumber(s.miner, s.bc, blockNr)
if block == nil {
return nil, nil
}
state, err := state.New(block.Root(), s.chainDb)
if err != nil {
return nil, err
}
return state.GetBalance(address), nil
}
// validatePool removes invalid and processed transactions from the main pool.
// If a transaction is removed for being invalid (e.g. out of funds), all sub-
// sequent (Still valid) transactions are moved back into the future queue. This
// is important to prevent a drained account from DOSing the network with non
// executable transactions.
func (pool *TxPool) validatePool() {
state, err := pool.currentState()
if err != nil {
glog.V(logger.Info).Infoln("failed to get current state: %v", err)
return
}
balanceCache := make(map[common.Address]*big.Int)
// Clean up the pending pool, accumulating invalid nonces
gaps := make(map[common.Address]uint64)
for hash, tx := range pool.pending {
sender, _ := tx.From() // err already checked
// Perform light nonce and balance validation
balance := balanceCache[sender]
if balance == nil {
balance = state.GetBalance(sender)
balanceCache[sender] = balance
}
if past := state.GetNonce(sender) > tx.Nonce(); past || balance.Cmp(tx.Cost()) < 0 {
// Remove an already past it invalidated transaction
if glog.V(logger.Core) {
glog.Infof("removed tx (%v) from pool: low tx nonce or out of funds\n", tx)
}
delete(pool.pending, hash)
// Track the smallest invalid nonce to postpone subsequent transactions
if !past {
if prev, ok := gaps[sender]; !ok || tx.Nonce() < prev {
gaps[sender] = tx.Nonce()
}
}
}
}
// Move all transactions after a gap back to the future queue
if len(gaps) > 0 {
for hash, tx := range pool.pending {
sender, _ := tx.From()
if gap, ok := gaps[sender]; ok && tx.Nonce() >= gap {
if glog.V(logger.Core) {
glog.Infof("postponed tx (%v) due to introduced gap\n", tx)
}
pool.queueTx(hash, tx)
delete(pool.pending, hash)
}
}
}
}