dex,client/asset: add token primitives

dex:
Token and Gases are used to specify token info in higher-level
packages, where lgpl builds are not suitable.
Add a test token ID.

client/asset:
The Token type embeds dex.Token and adds a WalletDefinition. This
type is used to register tokens with the package-level RegisterToken
method.

client/asset/eth:
The test token is registered with it's WalletDefinition. The
definition has 1 ConfigOption, limitAllowance, that allows the user
to keep a limited allowance for the swap contract, but with extra
transactions = more fees.

client/asset/driver.go

@@ -13,6 +13,7 @@ import (
 var (
 	driversMtx sync.RWMutex
 	drivers    = make(map[uint32]Driver)
+	tokens     = make(map[uint32]*Token)
 )
 
 // CreateWalletParams are the parameters for internal wallet creation. The
@@ -70,6 +71,23 @@ func Register(assetID uint32, driver Driver) {
 	drivers[assetID] = driver
 }
 
+// RegisterToken should be called to register tokens.
+func RegisterToken(tokenID uint32, token *dex.Token, walletDef *WalletDefinition) {
+	driversMtx.Lock()
+	defer driversMtx.Unlock()
+	if _, exists := tokens[tokenID]; exists {
+		panic(fmt.Sprintf("token %d already exists", tokenID))
+	}
+	_, exists := drivers[token.ParentID]
+	if !exists {
+		panic(fmt.Sprintf("token %d's parent asset %d isn't registered", tokenID, token.ParentID))
+	}
+	tokens[tokenID] = &Token{
+		Token:      token,
+		Definition: walletDef,
+	}
+}
+
 // WalletExists will be true if the specified wallet exists.
 func WalletExists(assetID uint32, walletType, dataDir string, settings map[string]string, net dex.Network) (exists bool, err error) {
 	return exists, withDriver(assetID, func(drv Driver) error {
@@ -115,6 +133,7 @@ type RegisteredAsset struct {
 	ID     uint32
 	Symbol string
 	Info   *WalletInfo
+	Tokens map[uint32]*Token
 }
 
 // Assets returns a list of information about supported assets.
@@ -129,10 +148,30 @@ func Assets() map[uint32]RegisteredAsset {
 			Info:   driver.Info(),
 		}
 	}
+	for tokenID, token := range tokens {
+		parent, found := assets[token.ParentID]
+		if !found {
+			// should be impossible.
+			fmt.Println("parentless token", tokenID, token.Name)
+			continue
+		}
+		if parent.Tokens == nil {
+			parent.Tokens = make(map[uint32]*Token, 1)
+		}
+		parent.Tokens[tokenID] = token
+	}
 	return assets
 }
 
-// Info returns the WalletInfo for the specified asset, if supported.
+// Token returns *Token for a registered token, or nil if the token is unknown.
+func TokenInfo(assetID uint32) *Token {
+	driversMtx.RLock()
+	defer driversMtx.RUnlock()
+	return tokens[assetID]
+}
+
+// Info returns the WalletInfo for the specified asset, if supported. Info only
+// returns WalletInfo for base chain assets, not tokens.
 func Info(assetID uint32) (*WalletInfo, error) {
 	driversMtx.RLock()
 	drv, ok := drivers[assetID]
@@ -142,3 +181,18 @@ func Info(assetID uint32) (*WalletInfo, error) {
 	}
 	return drv.Info(), nil
 }
+
+// UnitInfo returns the dex.UnitInfo for the asset or token.
+func UnitInfo(assetID uint32) (dex.UnitInfo, error) {
+	driversMtx.RLock()
+	defer driversMtx.RUnlock()
+	drv, ok := drivers[assetID]
+	if ok {
+		return drv.Info().UnitInfo, nil
+	}
+	token, ok := tokens[assetID]
+	if ok {
+		return token.UnitInfo, nil
+	}
+	return dex.UnitInfo{}, fmt.Errorf("asset: unsupported asset %d", assetID)
+}

client/asset/eth/eth.go

@@ -34,8 +34,23 @@ import (
 	"github.com/ethereum/go-ethereum/crypto"
 )
 
+var (
+	testTokenID, _ = dex.BipSymbolID("dextt.eth")
+)
+
+func registerToken(tokenID uint32, desc string) {
+	token := dexeth.Tokens[tokenID]
+	asset.RegisterToken(tokenID, token, &asset.WalletDefinition{
+		Type:        "token",
+		Description: desc,
+	})
+}
+
 func init() {
 	asset.Register(BipID, &Driver{})
+
+	// Test token
+	registerToken(testTokenID, "A token wallet for the DEX test token. Used for testing DEX software.")
 }
 
 const (

client/asset/eth/eth_test.go

@@ -891,9 +891,9 @@ func TestPreSwap(t *testing.T) {
 
 			wantLots:      1,
 			wantValue:     ethToGwei(10),
-			wantMaxFees:   100 * gases.InitGas,
-			wantBestCase:  90 * gases.InitGas,
-			wantWorstCase: 90 * gases.InitGas,
+			wantMaxFees:   100 * gases.Swap,
+			wantBestCase:  90 * gases.Swap,
+			wantWorstCase: 90 * gases.Swap,
 		},
 		{
 			name:          "more lots than max lots",
@@ -915,9 +915,9 @@ func TestPreSwap(t *testing.T) {
 
 			wantLots:      4,
 			wantValue:     ethToGwei(40),
-			wantMaxFees:   4 * 100 * gases.InitGas,
-			wantBestCase:  90 * (gases.InitGas + 3*gases.AdditionalInitGas),
-			wantWorstCase: 4 * 90 * gases.InitGas,
+			wantMaxFees:   4 * 100 * gases.Swap,
+			wantBestCase:  90 * gases.SwapN(4),
+			wantWorstCase: 4 * 90 * gases.Swap,
 		},
 		{
 			name:          "balanceError",
@@ -936,7 +936,7 @@ func TestPreSwap(t *testing.T) {
 		ID:           60,
 		Symbol:       "ETH",
 		MaxFeeRate:   100,
-		SwapSize:     gases.InitGas,
+		SwapSize:     gases.Swap,
 		SwapSizeBase: 0,
 		SwapConf:     1,
 	}
@@ -1535,10 +1535,10 @@ func TestMaxOrder(t *testing.T) {
 			maxFeeRate:    100,
 			wantLots:      1,
 			wantValue:     ethToGwei(10),
-			wantMaxFees:   100 * gases.InitGas,
-			wantBestCase:  90 * gases.InitGas,
-			wantWorstCase: 90 * gases.InitGas,
-			wantLocked:    ethToGwei(10) + (100 * gases.InitGas),
+			wantMaxFees:   100 * gases.Swap,
+			wantBestCase:  90 * gases.Swap,
+			wantWorstCase: 90 * gases.Swap,
+			wantLocked:    ethToGwei(10) + (100 * gases.Swap),
 		},
 		{
 			name:          "multiple lots",
@@ -1548,10 +1548,10 @@ func TestMaxOrder(t *testing.T) {
 			maxFeeRate:    100,
 			wantLots:      5,
 			wantValue:     ethToGwei(50),
-			wantMaxFees:   5 * 100 * gases.InitGas,
-			wantBestCase:  90 * (gases.InitGas + 4*gases.AdditionalInitGas),
-			wantWorstCase: 5 * 90 * gases.InitGas,
-			wantLocked:    ethToGwei(50) + (5 * 100 * gases.InitGas),
+			wantMaxFees:   5 * 100 * gases.Swap,
+			wantBestCase:  90 * gases.SwapN(5),
+			wantWorstCase: 5 * 90 * gases.Swap,
+			wantLocked:    ethToGwei(50) + (5 * 100 * gases.Swap),
 		},
 		{
 			name:          "balanceError",
@@ -1568,7 +1568,7 @@ func TestMaxOrder(t *testing.T) {
 		ID:           60,
 		Symbol:       "ETH",
 		MaxFeeRate:   100,
-		SwapSize:     gases.InitGas,
+		SwapSize:     gases.Swap,
 		SwapSizeBase: 0,
 		SwapConf:     1,
 	}

client/asset/eth/nodeclient_harness_test.go

@@ -558,10 +558,10 @@ func TestInitiateGas(t *testing.T) {
 		var expectedGas uint64
 		var actualGas uint64
 		if i == 1 {
-			expectedGas = gases.InitGas
+			expectedGas = gases.Swap
 			actualGas = gas
 		} else {
-			expectedGas = gases.AdditionalInitGas
+			expectedGas = gases.SwapAdd
 			actualGas = gas - previousGas
 		}
 		if actualGas > expectedGas || actualGas < expectedGas/100*95 {
@@ -814,10 +814,10 @@ func TestRedeemGas(t *testing.T) {
 		var expectedGas uint64
 		var actualGas uint64
 		if i == 0 {
-			expectedGas = gases.RedeemGas
+			expectedGas = gases.Redeem
 			actualGas = gas
 		} else {
-			expectedGas = gases.AdditionalRedeemGas
+			expectedGas = gases.RedeemAdd
 			actualGas = gas - previous
 		}
 		if actualGas > expectedGas || actualGas < (expectedGas/100*95) {

client/asset/interface.go

@@ -44,6 +44,12 @@ type WalletDefinition struct {
 	ConfigOpts []*ConfigOption `json:"configopts"`
 }
 
+// Token combines the generic dex.Token with a WalletDefinition.
+type Token struct {
+	*dex.Token
+	Definition *WalletDefinition `json:"definition"`
+}
+
 // WalletInfo is auxiliary information about an ExchangeWallet.
 type WalletInfo struct {
 	// Name is the display name for the currency, e.g. "Decred"
@@ -227,6 +233,17 @@ type Wallet interface {
 	RegFeeConfirmations(ctx context.Context, coinID dex.Bytes) (confs uint32, err error)
 }
 
+// TokenMaster is implemented by assets which support degenerate tokens.
+type TokenMaster interface {
+	// CreateTokenWallet creates a wallet for the specified token asset. The
+	// settings correspond to the Token.Definition.ConfigOpts.
+	CreateTokenWallet(assetID uint32, settings map[string]string) error
+	// OpenTokenWallet opens a wallet for the specified token asset. The
+	// settings correspond to the Token.Definition.ConfigOpts. The tipChange
+	// function will be called after the parent's tipChange function.
+	OpenTokenWallet(assetID uint32, settings map[string]string, tipChange func(error)) (Wallet, error)
+}
+
 // Balance is categorized information about a wallet's balance.
 type Balance struct {
 	// Available is the balance that is available for trading immediately.