Golang Currency.Add方法代碼示例

// Info returns generic information about the renter and the files that are
// being rented.
func (r *Renter) Info() (ri modules.RentInfo) {
	lockID := r.mu.RLock()
	// Include the list of files the renter knows about.
	for filename := range r.files {
		ri.Files = append(ri.Files, filename)
	}
	r.mu.RUnlock(lockID)

	// Calculate the average cost of a file.
	var totalPrice types.Currency
	sampleSize := defaultParityPieces + defaultDataPieces
	hosts := r.hostDB.RandomHosts(sampleSize)
	for _, host := range hosts {
		totalPrice = totalPrice.Add(host.Price)
	}
	if len(hosts) == 0 {
		return
	}
	averagePrice := totalPrice.Div(types.NewCurrency64(uint64(len(hosts))))
	estimatedCost := averagePrice.Mul(types.NewCurrency64(defaultDuration)).Mul(types.NewCurrency64(1e9)).Mul(types.NewCurrency64(defaultParityPieces + defaultDataPieces))
	// this also accounts for the buffering in the contract negotiation
	bufferedCost := estimatedCost.Mul(types.NewCurrency64(5)).Div(types.NewCurrency64(2))
	ri.Price = bufferedCost

	// Report the number of known hosts.
	ri.KnownHosts = len(r.hostDB.ActiveHosts())

	return
}

// checkWalletBalance looks at an upload and determines if there is enough
// money in the wallet to support such an upload. An error is returned if it is
// determined that there is not enough money.
func (r *Renter) checkWalletBalance(up modules.FileUploadParams) error {
	// Get the size of the file.
	fileInfo, err := os.Stat(up.Filename)
	if err != nil {
		return err
	}
	curSize := types.NewCurrency64(uint64(fileInfo.Size()))

	var averagePrice types.Currency
	sampleSize := up.ErasureCode.NumPieces() * 3 / 2
	hosts := r.hostDB.RandomHosts(sampleSize)
	for _, host := range hosts {
		averagePrice = averagePrice.Add(host.Price)
	}
	if len(hosts) == 0 {
		return errors.New("no hosts!")
	}
	averagePrice = averagePrice.Div(types.NewCurrency64(uint64(len(hosts))))
	estimatedCost := averagePrice.Mul(types.NewCurrency64(uint64(up.Duration))).Mul(curSize)
	bufferedCost := estimatedCost.Mul(types.NewCurrency64(2))

	siacoinBalance, _, _ := r.wallet.ConfirmedBalance()
	if bufferedCost.Cmp(siacoinBalance) > 0 {
		return errors.New("insufficient balance for upload")
	}
	return nil
}

// maxSectors is the estimated maximum number of sectors that the allowance
// can support.
func maxSectors(a modules.Allowance, hdb hostDB) (uint64, error) {
	if a.Hosts == 0 || a.Period == 0 {
		return 0, errors.New("invalid allowance")
	}

	// Sample at least 10 hosts.
	nRandomHosts := int(a.Hosts)
	if nRandomHosts < 10 {
		nRandomHosts = 10
	}
	hosts := hdb.RandomHosts(nRandomHosts, nil)
	if len(hosts) < int(a.Hosts) {
		return 0, errors.New("not enough hosts")
	}

	// Calculate cost of storing 1 sector per host for the allowance period.
	var sum types.Currency
	for _, h := range hosts {
		sum = sum.Add(h.StoragePrice)
	}
	averagePrice := sum.Div64(uint64(len(hosts)))
	costPerSector := averagePrice.Mul64(a.Hosts).Mul64(modules.SectorSize).Mul64(uint64(a.Period))

	// Divide total funds by cost per sector.
	numSectors, err := a.Funds.Div(costPerSector).Uint64()
	if err != nil {
		// if there was an overflow, something is definitely wrong
		return 0, errors.New("allowance can fund suspiciously large number of sectors")
	}
	return numSectors, nil
}

// checkSiacoins counts the number of siacoins in the database and verifies
// that it matches the sum of all the coinbases.
func (cs *ConsensusSet) checkSiacoins() error {
	// Calculate the number of expected coins in constant time.
	deflationBlocks := types.InitialCoinbase - types.MinimumCoinbase
	expectedSiacoins := types.CalculateCoinbase(0).Add(types.CalculateCoinbase(cs.height())).Div(types.NewCurrency64(2))
	if cs.height() < types.BlockHeight(deflationBlocks) {
		expectedSiacoins = expectedSiacoins.Mul(types.NewCurrency64(uint64(cs.height()) + 1))
	} else {
		expectedSiacoins = expectedSiacoins.Mul(types.NewCurrency64(deflationBlocks + 1))
		trailingSiacoins := types.NewCurrency64(uint64(cs.height()) - deflationBlocks).Mul(types.CalculateCoinbase(cs.height()))
		expectedSiacoins = expectedSiacoins.Add(trailingSiacoins)
	}

	totalSiacoins := types.ZeroCurrency
	cs.db.forEachSiacoinOutputs(func(scoid types.SiacoinOutputID, sco types.SiacoinOutput) {
		totalSiacoins = totalSiacoins.Add(sco.Value)
	})
	cs.db.forEachFileContracts(func(fcid types.FileContractID, fc types.FileContract) {
		var payout types.Currency
		for _, output := range fc.ValidProofOutputs {
			payout = payout.Add(output.Value)
		}
		totalSiacoins = totalSiacoins.Add(payout)
	})
	cs.db.forEachDelayedSiacoinOutputs(func(v types.SiacoinOutputID, dso types.SiacoinOutput) {
		totalSiacoins = totalSiacoins.Add(dso.Value)
	})
	cs.db.forEachSiafundOutputs(func(sfoid types.SiafundOutputID, sfo types.SiafundOutput) {
		sfoSiacoins := cs.siafundPool.Sub(sfo.ClaimStart).Div(types.SiafundCount).Mul(sfo.Value)
		totalSiacoins = totalSiacoins.Add(sfoSiacoins)
	})
	if expectedSiacoins.Cmp(totalSiacoins) != 0 {
		return errSiacoinMiscount
	}
	return nil
}

// validUnconfirmedSiafunds checks that all siafund inputs and outputs are
// valid within the context of the unconfirmed consensus set.
func (tp *TransactionPool) validUnconfirmedSiafunds(t types.Transaction) (err error) {
	var inputSum types.Currency
	for _, sfi := range t.SiafundInputs {
		// Check that the corresponding siafund output being spent exists.
		sfo, exists := tp.siafundOutputs[sfi.ParentID]
		if !exists {
			return errors.New("transaction spends unrecognized siafund output")
		}

		// Check that the unlock conditions match the unlock hash of the
		// corresponding output.
		if sfi.UnlockConditions.UnlockHash() != sfo.UnlockHash {
			return errors.New("transaction contains invalid unlock conditions (hash mismatch)")
		}

		// Add this input's value to the inputSum.
		inputSum = inputSum.Add(sfo.Value)
	}

	// Check that the value of the outputs equal the value of the inputs.
	var outputSum types.Currency
	for _, sfo := range t.SiafundOutputs {
		outputSum = outputSum.Add(sfo.Value)
	}
	if outputSum.Cmp(inputSum) != 0 {
		return errors.New("siafund inputs do not equal siafund outputs")
	}

	return
}

// checkMinerFees checks that the total amount of transaction fees in the
// transaction set is sufficient to earn a spot in the transaction pool.
func (tp *TransactionPool) checkMinerFees(ts []types.Transaction) error {
	// Transactions cannot be added after the TransactionPoolSizeLimit has been
	// hit.
	if tp.transactionListSize > TransactionPoolSizeLimit {
		return errFullTransactionPool
	}

	// The first TransactionPoolSizeForFee transactions do not need fees.
	if tp.transactionListSize > TransactionPoolSizeForFee {
		// Currently required fees are set on a per-transaction basis. 2 coins
		// are required per transaction if the free-fee limit has been reached,
		// adding a larger fee is not useful.
		var feeSum types.Currency
		for i := range ts {
			for _, fee := range ts[i].MinerFees {
				feeSum = feeSum.Add(fee)
			}
		}
		feeRequired := TransactionMinFee.Mul(types.NewCurrency64(uint64(len(ts))))
		if feeSum.Cmp(feeRequired) < 0 {
			return errLowMinerFees
		}
	}
	return nil
}

// Info returns generic information about the renter and the files that are
// being rented.
func (r *Renter) Info() (ri modules.RentInfo) {
	lockID := r.mu.RLock()
	defer r.mu.RUnlock(lockID)

	// Include the list of files the renter knows about.
	for filename := range r.files {
		ri.Files = append(ri.Files, filename)
	}

	// Calculate the average cost of a file.
	var totalPrice types.Currency
	redundancy := 6 // reasonable estimate until we come up with an alternative
	sampleSize := redundancy * 3 / 2
	hosts := r.hostDB.RandomHosts(sampleSize)
	for _, host := range hosts {
		totalPrice = totalPrice.Add(host.Price)
	}
	if len(hosts) == 0 {
		return
	}
	averagePrice := totalPrice.Mul(types.NewCurrency64(2)).Div(types.NewCurrency64(3))
	// HACK: 6000 is the duration (set by the API), and 1024^3 is a GB. Price
	// is reported as per GB, no timeframe is given.
	estimatedCost := averagePrice.Mul(types.NewCurrency64(6000)).Mul(types.NewCurrency64(1024 * 1024 * 1024))
	bufferedCost := estimatedCost.Mul(types.NewCurrency64(4)).Div(types.NewCurrency64(3))
	ri.Price = bufferedCost

	// Report the number of known hosts.
	ri.KnownHosts = len(r.hostDB.ActiveHosts())

	return
}

// validSiafunds checks that the siafund portions of the transaction are valid
// in the context of the consensus set.
func (cs *ConsensusSet) validSiafunds(t types.Transaction) (err error) {
	// Compare the number of input siafunds to the output siafunds.
	var siafundInputSum types.Currency
	var siafundOutputSum types.Currency
	for _, sfi := range t.SiafundInputs {
		exists := cs.db.inSiafundOutputs(sfi.ParentID)
		if !exists {
			return ErrMissingSiafundOutput
		}
		sfo := cs.db.getSiafundOutputs(sfi.ParentID)

		// Check the unlock conditions match the unlock hash.
		if sfi.UnlockConditions.UnlockHash() != sfo.UnlockHash {
			return ErrWrongUnlockConditions
		}

		siafundInputSum = siafundInputSum.Add(sfo.Value)
	}
	for _, sfo := range t.SiafundOutputs {
		siafundOutputSum = siafundOutputSum.Add(sfo.Value)
	}
	if siafundOutputSum.Cmp(siafundInputSum) != 0 {
		return ErrSiafundInputOutputMismatch
	}
	return
}

// SendSiacoins creates a transaction sending 'amount' to 'dest'. The transaction
// is submitted to the transaction pool and is also returned.
func (w *Wallet) SendSiacoins(amount types.Currency, dest types.UnlockHash) ([]types.Transaction, error) {
	if err := w.tg.Add(); err != nil {
		return nil, err
	}
	defer w.tg.Done()

	tpoolFee := types.SiacoinPrecision.Mul64(10) // TODO: better fee algo.
	output := types.SiacoinOutput{
		Value:      amount,
		UnlockHash: dest,
	}

	txnBuilder := w.StartTransaction()
	err := txnBuilder.FundSiacoins(amount.Add(tpoolFee))
	if err != nil {
		return nil, err
	}
	txnBuilder.AddMinerFee(tpoolFee)
	txnBuilder.AddSiacoinOutput(output)
	txnSet, err := txnBuilder.Sign(true)
	if err != nil {
		return nil, err
	}
	err = w.tpool.AcceptTransactionSet(txnSet)
	if err != nil {
		return nil, err
	}
	return txnSet, nil
}

// validSiacoins checks that the siacoin inputs and outputs are valid in the
// context of the current consensus set.
func validSiacoins(tx *bolt.Tx, t types.Transaction) error {
	scoBucket := tx.Bucket(SiacoinOutputs)
	var inputSum types.Currency
	for _, sci := range t.SiacoinInputs {
		// Check that the input spends an existing output.
		scoBytes := scoBucket.Get(sci.ParentID[:])
		if scoBytes == nil {
			return errMissingSiacoinOutput
		}

		// Check that the unlock conditions match the required unlock hash.
		var sco types.SiacoinOutput
		err := encoding.Unmarshal(scoBytes, &sco)
		if build.DEBUG && err != nil {
			panic(err)
		}
		if sci.UnlockConditions.UnlockHash() != sco.UnlockHash {
			return errWrongUnlockConditions
		}

		inputSum = inputSum.Add(sco.Value)
	}
	if inputSum.Cmp(t.SiacoinOutputSum()) != 0 {
		return errSiacoinInputOutputMismatch
	}
	return nil
}

// validSiafunds checks that the siafund portions of the transaction are valid
// in the context of the consensus set.
func validSiafunds(tx *bolt.Tx, t types.Transaction) (err error) {
	// Compare the number of input siafunds to the output siafunds.
	var siafundInputSum types.Currency
	var siafundOutputSum types.Currency
	for _, sfi := range t.SiafundInputs {
		sfo, err := getSiafundOutput(tx, sfi.ParentID)
		if err != nil {
			return err
		}

		// Check the unlock conditions match the unlock hash.
		if sfi.UnlockConditions.UnlockHash() != sfo.UnlockHash {
			return errWrongUnlockConditions
		}

		siafundInputSum = siafundInputSum.Add(sfo.Value)
	}
	for _, sfo := range t.SiafundOutputs {
		siafundOutputSum = siafundOutputSum.Add(sfo.Value)
	}
	if siafundOutputSum.Cmp(siafundInputSum) != 0 {
		return errSiafundInputOutputMismatch
	}
	return
}

// wallettransactionscmd lists all of the transactions related to the wallet,
// providing a net flow of siacoins and siafunds for each.
func wallettransactionscmd() {
	wtg := new(api.WalletTransactionsGET)
	err := getAPI("/wallet/transactions?startheight=0&endheight=10000000", wtg)
	if err != nil {
		fmt.Println("Could not fetch transaction history:", err)
		return
	}

	fmt.Println("    [height]                                                   [transaction id]    [net siacoins]   [net siafunds]")
	txns := append(wtg.ConfirmedTransactions, wtg.UnconfirmedTransactions...)
	for _, txn := range txns {
		// Determine the number of outgoing siacoins and siafunds.
		var outgoingSiacoins types.Currency
		var outgoingSiafunds types.Currency
		for _, input := range txn.Inputs {
			if input.FundType == types.SpecifierSiacoinInput && input.WalletAddress {
				outgoingSiacoins = outgoingSiacoins.Add(input.Value)
			}
			if input.FundType == types.SpecifierSiafundInput && input.WalletAddress {
				outgoingSiafunds = outgoingSiafunds.Add(input.Value)
			}
		}

		// Determine the number of incoming siacoins and siafunds.
		var incomingSiacoins types.Currency
		var incomingSiafunds types.Currency
		for _, output := range txn.Outputs {
			if output.FundType == types.SpecifierMinerPayout {
				incomingSiacoins = incomingSiacoins.Add(output.Value)
			}
			if output.FundType == types.SpecifierSiacoinOutput && output.WalletAddress {
				incomingSiacoins = incomingSiacoins.Add(output.Value)
			}
			if output.FundType == types.SpecifierSiafundOutput && output.WalletAddress {
				incomingSiafunds = incomingSiafunds.Add(output.Value)
			}
		}

		// Convert the siacoins to a float.
		incomingSiacoinsFloat, _ := new(big.Rat).SetFrac(incomingSiacoins.Big(), types.SiacoinPrecision.Big()).Float64()
		outgoingSiacoinsFloat, _ := new(big.Rat).SetFrac(outgoingSiacoins.Big(), types.SiacoinPrecision.Big()).Float64()

		// Print the results.
		if txn.ConfirmationHeight < 1e9 {
			fmt.Printf("%12v", txn.ConfirmationHeight)
		} else {
			fmt.Printf(" unconfirmed")
		}
		fmt.Printf("%67v%15.2f SC", txn.TransactionID, incomingSiacoinsFloat-outgoingSiacoinsFloat)
		// For siafunds, need to avoid having a negative types.Currency.
		if incomingSiafunds.Cmp(outgoingSiafunds) >= 0 {
			fmt.Printf("%14v SF\n", incomingSiafunds.Sub(outgoingSiafunds))
		} else {
			fmt.Printf("-%14v SF\n", outgoingSiafunds.Sub(incomingSiafunds))
		}
	}
}

// CalculateFee returns the fee-per-byte of a transaction set.
func CalculateFee(ts []types.Transaction) types.Currency {
	var sum types.Currency
	for _, t := range ts {
		for _, fee := range t.MinerFees {
			sum = sum.Add(fee)
		}
	}
	size := len(encoding.Marshal(ts))
	return sum.Div64(uint64(size))
}

// checkMinerPayouts compares a block's miner payouts to the block's subsidy and
// returns true if they are equal.
func checkMinerPayouts(b types.Block, height types.BlockHeight) bool {
	// Add up the payouts and check that all values are legal.
	var payoutSum types.Currency
	for _, payout := range b.MinerPayouts {
		if payout.Value.IsZero() {
			return false
		}
		payoutSum = payoutSum.Add(payout.Value)
	}
	return b.CalculateSubsidy(height).Cmp(payoutSum) == 0
}

// AveragePrice returns the average price of a host.
func (hdb *HostDB) AveragePrice() types.Currency {
	// maybe a more sophisticated way of doing this
	var totalPrice types.Currency
	sampleSize := 18
	hosts := hdb.randomHosts(sampleSize, nil)
	if len(hosts) == 0 {
		return totalPrice
	}
	for _, host := range hosts {
		totalPrice = totalPrice.Add(host.Price)
	}
	return totalPrice.Div(types.NewCurrency64(uint64(len(hosts))))
}