Golang types.Currency類代碼示例

// newRevision revises the current revision to incorporate new data.
func newRevision(rev types.FileContractRevision, pieceLen uint64, merkleRoot crypto.Hash, piecePrice types.Currency) types.FileContractRevision {
	// prevent a negative currency panic
	if piecePrice.Cmp(rev.NewValidProofOutputs[0].Value) > 0 {
		// probably not enough money, but the host might accept it anyway
		piecePrice = rev.NewValidProofOutputs[0].Value
	}
	return types.FileContractRevision{
		ParentID:          rev.ParentID,
		UnlockConditions:  rev.UnlockConditions,
		NewRevisionNumber: rev.NewRevisionNumber + 1,
		NewFileSize:       rev.NewFileSize + pieceLen,
		NewFileMerkleRoot: merkleRoot,
		NewWindowStart:    rev.NewWindowStart,
		NewWindowEnd:      rev.NewWindowEnd,
		NewValidProofOutputs: []types.SiacoinOutput{
			// less returned to renter
			{Value: rev.NewValidProofOutputs[0].Value.Sub(piecePrice), UnlockHash: rev.NewValidProofOutputs[0].UnlockHash},
			// more given to host
			{Value: rev.NewValidProofOutputs[1].Value.Add(piecePrice), UnlockHash: rev.NewValidProofOutputs[1].UnlockHash},
		},
		NewMissedProofOutputs: []types.SiacoinOutput{
			// less returned to renter
			{Value: rev.NewMissedProofOutputs[0].Value.Sub(piecePrice), UnlockHash: rev.NewMissedProofOutputs[0].UnlockHash},
			// more given to void
			{Value: rev.NewMissedProofOutputs[1].Value.Add(piecePrice), UnlockHash: rev.NewMissedProofOutputs[1].UnlockHash},
		},
		NewUnlockHash: rev.NewUnlockHash,
	}
}

// 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
}

// 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
}

// 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
}

// findOutputs returns a set of spendable outputs that add up to at least
// `amount` of coins, returning an error if it cannot. It also returns the
// `total`, which is the sum of all the outputs that were found, since it's
// unlikely that it will equal amount exaclty.
func (w *Wallet) findOutputs(amount types.Currency) (knownOutputs []*knownOutput, total types.Currency, err error) {
	if amount.IsZero() {
		err = errors.New("cannot fund amount <= 0")
		return
	}

	// Iterate through all outputs until enough coins have been assembled.
	for _, key := range w.keys {
		if !key.spendable {
			continue
		}
		for _, knownOutput := range key.outputs {
			if !knownOutput.spendable {
				continue
			}
			if knownOutput.age > w.age-AgeDelay {
				continue
			}
			total = total.Add(knownOutput.output.Value)
			knownOutputs = append(knownOutputs, knownOutput)

			if total.Cmp(amount) >= 0 {
				return
			}
		}
	}

	// This code will only be reached if total < amount, meaning insufficient
	// funds.
	err = modules.LowBalanceErr
	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
}

// 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
}

// 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
}

// 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
}

// TestRPCUPload attempts to upload a file to the host, adding coverage to the
// upload function.
func TestRPCUpload(t *testing.T) {
	if testing.Short() {
		t.SkipNow()
	}
	ht, err := newHostTester("TestRPCUpload")
	if err != nil {
		t.Fatal(err)
	}
	ht.host.mu.RLock()
	baselineAnticipatedRevenue := ht.host.anticipatedRevenue
	baselineSpace := ht.host.spaceRemaining
	ht.host.mu.RUnlock()
	_, err = ht.uploadFile("TestRPCUpload - 1", renewDisabled)
	if err != nil {
		t.Fatal(err)
	}

	var expectedRevenue types.Currency
	func() {
		ht.host.mu.RLock()
		defer ht.host.mu.RUnlock()

		if ht.host.anticipatedRevenue.Cmp(baselineAnticipatedRevenue) <= 0 {
			t.Error("Anticipated revenue did not increase after a file was uploaded")
		}
		if baselineSpace <= ht.host.spaceRemaining {
			t.Error("space remaining on the host does not seem to have decreased")
		}
		expectedRevenue = ht.host.anticipatedRevenue
	}()

	// Mine until the storage proof goes through, and the obligation gets
	// cleared.
	for i := types.BlockHeight(0); i <= testUploadDuration+confirmationRequirement+defaultWindowSize; i++ {
		_, err := ht.miner.AddBlock()
		if err != nil {
			t.Fatal(err)
		}
	}

	// Check that the storage proof has succeeded.
	ht.host.mu.Lock()
	defer ht.host.mu.Unlock()
	if len(ht.host.obligationsByID) != 0 {
		t.Error("host still has obligation, when it should have completed the obligation and submitted a storage proof.")
	}
	if !ht.host.anticipatedRevenue.IsZero() {
		t.Error("host anticipated revenue was not set back to zero")
	}
	if ht.host.spaceRemaining != baselineSpace {
		t.Error("host does not seem to have reclaimed the space after a successful obligation")
	}
	if expectedRevenue.Cmp(ht.host.revenue) != 0 {
		t.Error("host's revenue was not moved from anticipated to expected")
	}
}

// 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))))
}

// currencyUnits converts a types.Currency to a string with human-readable
// units. The unit used will be the largest unit that results in a value
// greater than 1. The value is rounded to 4 significant digits.
func currencyUnits(c types.Currency) string {
	pico := types.SiacoinPrecision.Div64(1e12)
	if c.Cmp(pico) < 0 {
		return c.String() + " H"
	}

	// iterate until we find a unit greater than c
	mag := pico
	unit := ""
	for _, unit = range []string{"pS", "nS", "uS", "mS", "SC", "KS", "MS", "GS", "TS"} {
		if c.Cmp(mag.Mul64(1e3)) < 0 {
			break
		} else if unit != "TS" {
			// don't want to perform this multiply on the last iter; that
			// would give us 1.235 TS instead of 1235 TS
			mag = mag.Mul64(1e3)
		}
	}

	num := new(big.Rat).SetInt(c.Big())
	denom := new(big.Rat).SetInt(mag.Big())
	res, _ := new(big.Rat).Mul(num, denom.Inv(denom)).Float64()

	return fmt.Sprintf("%.4g %s", res, unit)
}

// 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
}