swap, uint256: unify variable types, pt. 1 (#2063)

swap, uint256: add uint256 package and type, refactor Cheque cumulative payout field into uint256 type

swap/api.go

@@ -3,11 +3,13 @@ package swap
 import (
 	"encoding/json"
 	"fmt"
+	"math/big"
 
 	"github.com/ethereum/go-ethereum/p2p/enode"
 	"github.com/ethereum/go-ethereum/rpc"
 	contract "github.com/ethersphere/swarm/contracts/swap"
 	"github.com/ethersphere/swarm/state"
+	"github.com/ethersphere/swarm/uint256"
 )
 
 // APIs is a node.Service interface method
@@ -23,7 +25,7 @@ func (s *Swap) APIs() []rpc.API {
 }
 
 type swapAPI interface {
-	AvailableBalance() (uint64, error)
+	AvailableBalance() (*uint256.Uint256, error)
 	PeerBalance(peer enode.ID) (int64, error)
 	Balances() (map[enode.ID]int64, error)
 	PeerCheques(peer enode.ID) (PeerCheques, error)
@@ -52,22 +54,22 @@ func NewAPI(s *Swap) *API {
 }
 
 // AvailableBalance returns the total balance of the chequebook against which new cheques can be written
-func (s *Swap) AvailableBalance() (uint64, error) {
+func (s *Swap) AvailableBalance() (*uint256.Uint256, error) {
 	// get the LiquidBalance of the chequebook
-	liquidBalance, err := s.contract.LiquidBalance(nil)
+	contractLiquidBalance, err := s.contract.LiquidBalance(nil)
 	if err != nil {
-		return 0, err
+		return nil, err
 	}
 
 	// get all cheques
 	cheques, err := s.Cheques()
 	if err != nil {
-		return 0, err
+		return nil, err
 	}
 
 	// Compute the total worth of cheques sent and how much of of this is cashed
-	var sentChequesWorth uint64
-	var cashedChequesWorth uint64
+	sentChequesWorth := new(big.Int)
+	cashedChequesWorth := new(big.Int)
 	for _, peerCheques := range cheques {
 		var sentCheque *Cheque
 		if peerCheques.PendingCheque != nil {
@@ -77,14 +79,19 @@ func (s *Swap) AvailableBalance() (uint64, error) {
 		} else {
 			continue
 		}
-		sentChequesWorth += sentCheque.ChequeParams.CumulativePayout
+		cumulativePayout := sentCheque.ChequeParams.CumulativePayout.Value()
+		sentChequesWorth.Add(sentChequesWorth, &cumulativePayout)
 		paidOut, err := s.contract.PaidOut(nil, sentCheque.ChequeParams.Beneficiary)
 		if err != nil {
-			return 0, err
+			return nil, err
 		}
-		cashedChequesWorth += paidOut.Uint64()
+		cashedChequesWorth.Add(cashedChequesWorth, paidOut)
 	}
-	return liquidBalance.Uint64() + cashedChequesWorth - sentChequesWorth, nil
+
+	totalChequesWorth := new(big.Int).Sub(cashedChequesWorth, sentChequesWorth)
+	tentativeLiquidBalance := new(big.Int).Add(contractLiquidBalance, totalChequesWorth)
+
+	return uint256.New().Set(*tentativeLiquidBalance)
 }
 
 // PeerBalance returns the balance for a given peer

swap/cashout.go

@@ -18,7 +18,6 @@ package swap
 import (
 	"context"
 	"crypto/ecdsa"
-	"math/big"
 
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/common"
@@ -67,7 +66,8 @@ func (c *CashoutProcessor) cashCheque(ctx context.Context, request *CashoutReque
 		return err
 	}
 
-	tx, err := otherSwap.CashChequeBeneficiaryStart(opts, request.Destination, big.NewInt(int64(cheque.CumulativePayout)), cheque.Signature)
+	cumulativePayout := cheque.CumulativePayout.Value()
+	tx, err := otherSwap.CashChequeBeneficiaryStart(opts, request.Destination, &cumulativePayout, cheque.Signature)
 	if err != nil {
 		return err
 	}
@@ -98,11 +98,12 @@ func (c *CashoutProcessor) estimatePayout(ctx context.Context, cheque *Cheque) (
 
 	transactionCosts = gasPrice.Uint64() * CashChequeBeneficiaryTransactionCost
 
-	if paidOut.Cmp(big.NewInt(int64(cheque.CumulativePayout))) > 0 {
+	cumulativePayout := cheque.CumulativePayout.Value()
+	if paidOut.Cmp(&cumulativePayout) > 0 {
 		return 0, transactionCosts, nil
 	}
 
-	expectedPayout = cheque.CumulativePayout - paidOut.Uint64()
+	expectedPayout = (&cumulativePayout).Uint64() - paidOut.Uint64()
 
 	return expectedPayout, transactionCosts, nil
 }

swap/cashout_test.go

@@ -24,6 +24,7 @@ import (
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/log"
 	contract "github.com/ethersphere/swarm/contracts/swap"
+	"github.com/ethersphere/swarm/uint256"
 )
 
 // TestContractIntegration tests a end-to-end cheque interaction.
@@ -73,8 +74,13 @@ func TestContractIntegration(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if result.Uint64() != cheque.CumulativePayout {
-		t.Fatalf("Wrong cumulative payout %d", result)
+	paidOut, err := uint256.New().Set(*result)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !cheque.CumulativePayout.Equals(paidOut) {
+		t.Fatalf("Wrong cumulative payout %v", paidOut)
 	}
 	log.Debug("cheques result", "result", result)
 
@@ -84,7 +90,8 @@ func TestContractIntegration(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	tx, err = chequebook.CashChequeBeneficiaryStart(opts, beneficiaryAddress, big.NewInt(int64(bouncingCheque.CumulativePayout)), bouncingCheque.Signature)
+	cumulativePayout := bouncingCheque.CumulativePayout.Value()
+	tx, err = chequebook.CashChequeBeneficiaryStart(opts, beneficiaryAddress, &cumulativePayout, bouncingCheque.Signature)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -136,7 +143,8 @@ func TestCashCheque(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if paidOut.Cmp(big.NewInt(int64(testCheque.CumulativePayout))) != 0 {
+	cumulativePayout := testCheque.CumulativePayout.Value()
+	if paidOut.Cmp(&cumulativePayout) != 0 {
 		t.Fatalf("paidOut does not equal the CumulativePayout: paidOut=%v expected=%v", paidOut, testCheque.CumulativePayout)
 	}
 }

swap/cheque.go

@@ -19,19 +19,22 @@ package swap
 import (
 	"bytes"
 	"crypto/ecdsa"
-	"encoding/binary"
 	"fmt"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethersphere/swarm/uint256"
 )
 
 // encodeForSignature encodes the cheque params in the format used in the signing procedure
 func (cheque *ChequeParams) encodeForSignature() []byte {
 	cumulativePayoutBytes := make([]byte, 32)
 	// we need to write the last 8 bytes as we write a uint64 into a 32-byte array
 	// encoded in BigEndian because EVM uses BigEndian encoding
-	binary.BigEndian.PutUint64(cumulativePayoutBytes[24:], cheque.CumulativePayout)
+	cumulativePayout := cheque.CumulativePayout.Value()
+	chequePayoutBytes := (&cumulativePayout).Bytes()
+	copy(cumulativePayoutBytes[32-len(chequePayoutBytes):], chequePayoutBytes)
+
 	// construct the actual cheque
 	input := cheque.Contract.Bytes()
 	input = append(input, cheque.Beneficiary.Bytes()...)
@@ -94,7 +97,7 @@ func (cheque *Cheque) Equal(other *Cheque) bool {
 		return false
 	}
 
-	if cheque.CumulativePayout != other.CumulativePayout {
+	if !cheque.CumulativePayout.Equals(other.CumulativePayout) {
 		return false
 	}
 
@@ -130,24 +133,24 @@ func (cheque *Cheque) verifyChequeProperties(p *Peer, expectedBeneficiary common
 
 // verifyChequeAgainstLast verifies that the amount is higher than in the previous cheque and the increase is as expected
 // returns the actual amount received in this cheque
-func (cheque *Cheque) verifyChequeAgainstLast(lastCheque *Cheque, expectedAmount uint64) (uint64, error) {
-	actualAmount := cheque.CumulativePayout
+func (cheque *Cheque) verifyChequeAgainstLast(lastCheque *Cheque, expectedAmount *uint256.Uint256) (*uint256.Uint256, error) {
+	actualAmount := uint256.New().Copy(cheque.CumulativePayout)
 
 	if lastCheque != nil {
-		if cheque.CumulativePayout <= lastCheque.CumulativePayout {
-			return 0, fmt.Errorf("wrong cheque parameters: expected cumulative payout larger than %d, was: %d", lastCheque.CumulativePayout, cheque.CumulativePayout)
+		if cheque.CumulativePayout.Cmp(lastCheque.CumulativePayout) < 1 {
+			return nil, fmt.Errorf("wrong cheque parameters: expected cumulative payout larger than %v, was: %v", lastCheque.CumulativePayout, cheque.CumulativePayout)
 		}
 
-		actualAmount -= lastCheque.CumulativePayout
+		actualAmount.Sub(actualAmount, lastCheque.CumulativePayout)
 	}
 
-	if expectedAmount != actualAmount {
-		return 0, fmt.Errorf("unexpected amount for honey, expected %d was %d", expectedAmount, actualAmount)
+	if !expectedAmount.Equals(actualAmount) {
+		return nil, fmt.Errorf("unexpected amount for honey, expected %v was %v", expectedAmount, actualAmount)
 	}
 
 	return actualAmount, nil
 }
 
 func (cheque *Cheque) String() string {
-	return fmt.Sprintf("Contract: %x Beneficiary: %x CumulativePayout: %d Honey: %d", cheque.Contract, cheque.Beneficiary, cheque.CumulativePayout, cheque.Honey)
+	return fmt.Sprintf("Contract: %x Beneficiary: %x CumulativePayout: %v Honey: %d", cheque.Contract, cheque.Beneficiary, cheque.CumulativePayout, cheque.Honey)
 }

swap/common_test.go

@@ -24,6 +24,7 @@ import (
 	"github.com/ethersphere/swarm/network"
 	"github.com/ethersphere/swarm/p2p/protocols"
 	"github.com/ethersphere/swarm/state"
+	"github.com/ethersphere/swarm/uint256"
 )
 
 // swapTestBackend encapsulates the SimulatedBackend and can offer
@@ -167,7 +168,7 @@ func newTestCheque() *Cheque {
 	cheque := &Cheque{
 		ChequeParams: ChequeParams{
 			Contract:         testChequeContract,
-			CumulativePayout: uint64(42),
+			CumulativePayout: uint256.FromUint64(42),
 			Beneficiary:      beneficiaryAddress,
 		},
 		Honey: uint64(42),
@@ -180,7 +181,7 @@ func newSignedTestCheque(testChequeContract common.Address, beneficiaryAddress c
 	cheque := &Cheque{
 		ChequeParams: ChequeParams{
 			Contract:         testChequeContract,
-			CumulativePayout: cumulativePayout.Uint64(),
+			CumulativePayout: uint256.FromUint64(cumulativePayout.Uint64()),
 			Beneficiary:      beneficiaryAddress,
 		},
 		Honey: cumulativePayout.Uint64(),
@@ -196,15 +197,15 @@ func newSignedTestCheque(testChequeContract common.Address, beneficiaryAddress c
 
 // creates a randomized cheque structure for testing
 func newRandomTestCheque() *Cheque {
-	amount := mrand.Intn(100)
+	amount := uint64(mrand.Intn(100))
 
 	cheque := &Cheque{
 		ChequeParams: ChequeParams{
 			Contract:         testChequeContract,
-			CumulativePayout: uint64(amount),
+			CumulativePayout: uint256.FromUint64(amount),
 			Beneficiary:      beneficiaryAddress,
 		},
-		Honey: uint64(amount),
+		Honey: amount,
 	}
 
 	return cheque

swap/peer.go

@@ -27,6 +27,7 @@ import (
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/metrics"
 	"github.com/ethersphere/swarm/p2p/protocols"
+	"github.com/ethersphere/swarm/uint256"
 )
 
 // ErrDontOwe indictates that no balance is actially owned
@@ -116,12 +117,12 @@ func (p *Peer) setPendingCheque(cheque *Cheque) error {
 
 // getLastSentCumulativePayout returns the cumulative payout of the last sent cheque or 0 if there is none
 // the caller is expected to hold p.lock
-func (p *Peer) getLastSentCumulativePayout() uint64 {
+func (p *Peer) getLastSentCumulativePayout() *uint256.Uint256 {
 	lastCheque := p.getLastSentCheque()
 	if lastCheque != nil {
 		return lastCheque.CumulativePayout
 	}
-	return 0
+	return uint256.New()
 }
 
 // the caller is expected to hold p.lock
@@ -162,16 +163,21 @@ func (p *Peer) createCheque() (*Cheque, error) {
 	// the balance should be negative here, we take the absolute value:
 	honey := uint64(-p.getBalance())
 
-	amount, err := p.swap.honeyPriceOracle.GetPrice(honey)
+	oraclePrice, err := p.swap.honeyPriceOracle.GetPrice(honey)
 	if err != nil {
 		return nil, fmt.Errorf("error getting price from oracle: %v", err)
 	}
+	price := uint256.FromUint64(oraclePrice)
 
-	total := p.getLastSentCumulativePayout()
+	cumulativePayout := p.getLastSentCumulativePayout()
+	newCumulativePayout, err := uint256.New().Add(cumulativePayout, price)
+	if err != nil {
+		return nil, err
+	}
 
 	cheque = &Cheque{
 		ChequeParams: ChequeParams{
-			CumulativePayout: total + amount,
+			CumulativePayout: newCumulativePayout,
 			Contract:         p.swap.GetParams().ContractAddress,
 			Beneficiary:      p.beneficiary,
 		},

swap/protocol_test.go

@@ -35,6 +35,7 @@ import (
 	"github.com/ethereum/go-ethereum/rpc"
 	contract "github.com/ethersphere/swarm/contracts/swap"
 	p2ptest "github.com/ethersphere/swarm/p2p/testing"
+	"github.com/ethersphere/swarm/uint256"
 	colorable "github.com/mattn/go-colorable"
 )
 
@@ -245,9 +246,10 @@ func TestEmitCheque(t *testing.T) {
 	// gasPrice on testBackend == 1
 	// estimated gas costs == 50000
 	// cheque should be sent if the accumulated amount of uncashed cheques is worth more than 100000
-	balance := uint64(100001)
+	balance := uint256.FromUint64(100001)
+	balanceValue := balance.Value()
 
-	if err := testDeploy(context.Background(), debitorSwap, big.NewInt(int64(balance))); err != nil {
+	if err := testDeploy(context.Background(), debitorSwap, &balanceValue); err != nil {
 		t.Fatal(err)
 	}
 
@@ -260,7 +262,7 @@ func TestEmitCheque(t *testing.T) {
 
 	debitor := creditorSwap.getPeer(protocolTester.Nodes[0].ID())
 	// set balance artificially
-	if err = debitor.setBalance(int64(balance)); err != nil {
+	if err = debitor.setBalance(balanceValue.Int64()); err != nil {
 		t.Fatal(err)
 	}
 
@@ -275,7 +277,7 @@ func TestEmitCheque(t *testing.T) {
 			Beneficiary:      creditorSwap.owner.address,
 			CumulativePayout: balance,
 		},
-		Honey: balance,
+		Honey: balanceValue.Uint64(),
 	}
 	cheque.Signature, err = cheque.Sign(debitorSwap.owner.privateKey)
 	if err != nil {
@@ -380,8 +382,8 @@ func TestTriggerPaymentThreshold(t *testing.T) {
 		t.Fatal("Expected pending cheque")
 	}
 
-	if pending.CumulativePayout != expectedAmount {
-		t.Fatalf("Expected cheque cumulative payout to be %d, but is %d", expectedAmount, pending.CumulativePayout)
+	if !pending.CumulativePayout.Equals(uint256.FromUint64(expectedAmount)) {
+		t.Fatalf("Expected cheque cumulative payout to be %d, but is %v", expectedAmount, pending.CumulativePayout)
 	}
 
 	if pending.Honey != expectedAmount {