cli: implement AddressFlag

This makes code less verbose and performs all parsing
before invoking main function.

cli/flags/address.go

@@ -0,0 +1,78 @@
+package flags
+
+import (
+	"flag"
+	"fmt"
+	"strings"
+
+	"github.com/nspcc-dev/neo-go/pkg/encoding/address"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/urfave/cli"
+)
+
+// Address is a wrapper for Uint160 with flag.Value methods.
+type Address util.Uint160
+
+// AddressFlag is a flag with type string
+type AddressFlag struct {
+	Name  string
+	Usage string
+	Value Address
+}
+
+var (
+	_ flag.Value = (*Address)(nil)
+	_ cli.Flag   = AddressFlag{}
+)
+
+// String implements fmt.Stringer interface.
+func (a Address) String() string {
+	return address.Uint160ToString(util.Uint160(a))
+}
+
+// Set implements flag.Value interface.
+func (a *Address) Set(s string) error {
+	addr, err := address.StringToUint160(s)
+	if err != nil {
+		return cli.NewExitError(err, 1)
+	}
+	*a = Address(addr)
+	return nil
+}
+
+// Uint160 casts address to Uint160.
+func (a *Address) Uint160() (u util.Uint160) {
+	copy(u[:], a[:])
+	return
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f AddressFlag) String() string {
+	var names []string
+	eachName(f.Name, func(name string) {
+		names = append(names, getNameHelp(name))
+	})
+
+	return strings.Join(names, ", ") + "\t" + f.Usage
+}
+
+func getNameHelp(name string) string {
+	if len(name) == 1 {
+		return fmt.Sprintf("-%s value", name)
+	}
+	return fmt.Sprintf("--%s value", name)
+}
+
+// GetName returns the name of the flag
+func (f AddressFlag) GetName() string {
+	return f.Name
+}
+
+// Apply populates the flag given the flag set and environment
+// Ignores errors
+func (f AddressFlag) Apply(set *flag.FlagSet) {
+	eachName(f.Name, func(name string) {
+		set.Var(&f.Value, name, f.Usage)
+	})
+}

cli/flags/util.go

@@ -0,0 +1,11 @@
+package flags
+
+import "strings"
+
+func eachName(longName string, fn func(string)) {
+	parts := strings.Split(longName, ",")
+	for _, name := range parts {
+		name = strings.Trim(name, " ")
+		fn(name)
+	}
+}

cli/wallet/wallet.go

@@ -11,6 +11,7 @@ import (
 	"strings"
 	"syscall"
 
+	"github.com/nspcc-dev/neo-go/cli/flags"
 	"github.com/nspcc-dev/neo-go/pkg/core"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
@@ -74,7 +75,7 @@ func NewCommands() []cli.Command {
 					walletPathFlag,
 					rpcFlag,
 					timeoutFlag,
-					cli.StringFlag{
+					flags.AddressFlag{
 						Name:  "address, a",
 						Usage: "Address to claim GAS for",
 					},
@@ -162,11 +163,11 @@ func NewCommands() []cli.Command {
 					rpcFlag,
 					timeoutFlag,
 					outFlag,
-					cli.StringFlag{
+					flags.AddressFlag{
 						Name:  "from",
 						Usage: "Address to send an asset from",
 					},
-					cli.StringFlag{
+					flags.AddressFlag{
 						Name:  "to",
 						Usage: "Address to send an asset to",
 					},
@@ -196,15 +197,11 @@ func claimGas(ctx *cli.Context) error {
 	}
 	defer wall.Close()
 
-	addr := ctx.String("address")
-	scriptHash, err := address.StringToUint160(addr)
-	if err != nil {
-		return cli.NewExitError(err, 1)
-	}
-
+	addrFlag := ctx.Generic("address").(*flags.Address)
+	scriptHash := addrFlag.Uint160()
 	acc := wall.GetAccount(scriptHash)
 	if acc == nil {
-		return cli.NewExitError(fmt.Errorf("wallet contains no account for '%s'", addr), 1)
+		return cli.NewExitError(fmt.Errorf("wallet contains no account for '%s'", addrFlag), 1)
 	}
 
 	pass, err := readPassword("Enter password > ")
@@ -221,7 +218,7 @@ func claimGas(ctx *cli.Context) error {
 	if err != nil {
 		return cli.NewExitError(err, 1)
 	}
-	info, err := c.GetClaimable(addr)
+	info, err := c.GetClaimable(scriptHash.String())
 	if err != nil {
 		return cli.NewExitError(err, 1)
 	} else if info.Unclaimed == 0 || len(info.Spents) == 0 {
@@ -397,14 +394,11 @@ func transferAsset(ctx *cli.Context) error {
 	}
 	defer wall.Close()
 
-	from := ctx.String("from")
-	addr, err := address.StringToUint160(from)
-	if err != nil {
-		return cli.NewExitError("invalid address", 1)
-	}
-	acc := wall.GetAccount(addr)
+	fromFlag := ctx.Generic("from").(*flags.Address)
+	from := fromFlag.Uint160()
+	acc := wall.GetAccount(from)
 	if acc == nil {
-		return cli.NewExitError(fmt.Errorf("wallet contains no account for '%s'", addr), 1)
+		return cli.NewExitError(fmt.Errorf("wallet contains no account for '%s'", from), 1)
 	}
 
 	asset, err := getAssetID(ctx.String("asset"))
@@ -433,14 +427,11 @@ func transferAsset(ctx *cli.Context) error {
 	}
 
 	tx := transaction.NewContractTX()
-	if err := request.AddInputsAndUnspentsToTx(tx, from, asset, amount, c); err != nil {
+	if err := request.AddInputsAndUnspentsToTx(tx, fromFlag.String(), asset, amount, c); err != nil {
 		return cli.NewExitError(err, 1)
 	}
 
-	toAddr, err := address.StringToUint160(ctx.String("to"))
-	if err != nil {
-		return cli.NewExitError(err, 1)
-	}
+	toAddr := ctx.Generic("to").(*flags.Address).Uint160()
 	tx.AddOutput(&transaction.Output{
 		AssetID:    asset,
 		Amount:     amount,