cmd/utils: add BigFlag and use it for error-checked integer flags

While here, remove environment variable processing for DirectoryFlag
because we don't use it.

cmd/utils/customflags.go

@@ -17,12 +17,17 @@
 package utils
 
 import (
+	"errors"
 	"flag"
 	"fmt"
+	"math/big"
 	"os"
 	"os/user"
 	"path"
 	"strings"
+
+	"github.com/ethereum/go-ethereum/common/math"
+	"gopkg.in/urfave/cli.v1"
 )
 
 // Custom type which is registered in the flags library which cli uses for
@@ -44,10 +49,9 @@ func (self *DirectoryString) Set(value string) error {
 // Custom cli.Flag type which expand the received string to an absolute path.
 // e.g. ~/.ethereum -> /home/username/.ethereum
 type DirectoryFlag struct {
-	Name   string
-	Value  DirectoryString
-	Usage  string
-	EnvVar string
+	Name  string
+	Value DirectoryString
+	Usage string
 }
 
 func (self DirectoryFlag) String() string {
@@ -55,7 +59,7 @@ func (self DirectoryFlag) String() string {
 	if len(self.Value.Value) > 0 {
 		fmtString = "%s \"%v\"\t%v"
 	}
-	return withEnvHint(self.EnvVar, fmt.Sprintf(fmtString, prefixedNames(self.Name), self.Value.Value, self.Usage))
+	return fmt.Sprintf(fmtString, prefixedNames(self.Name), self.Value.Value, self.Usage)
 }
 
 func eachName(longName string, fn func(string)) {
@@ -69,21 +73,65 @@ func eachName(longName string, fn func(string)) {
 // called by cli library, grabs variable from environment (if in env)
 // and adds variable to flag set for parsing.
 func (self DirectoryFlag) Apply(set *flag.FlagSet) {
-	if self.EnvVar != "" {
-		for _, envVar := range strings.Split(self.EnvVar, ",") {
-			envVar = strings.TrimSpace(envVar)
-			if envVal := os.Getenv(envVar); envVal != "" {
-				self.Value.Value = envVal
-				break
-			}
-		}
-	}
-
 	eachName(self.Name, func(name string) {
 		set.Var(&self.Value, self.Name, self.Usage)
 	})
 }
 
+// BigFlag is a command line flag that accepts big integers in decimal
+// or hexadecimal syntax.
+type BigFlag struct {
+	Name  string
+	Value *big.Int
+	Usage string
+}
+
+// bigValue turns *big.Int into a flag.Value
+type bigValue big.Int
+
+func (b *bigValue) String() string {
+	if b == nil {
+		return ""
+	}
+	return (*big.Int)(b).String()
+}
+
+func (b *bigValue) Set(s string) error {
+	int, ok := math.ParseBig(s)
+	if !ok {
+		return errors.New("invalid integer syntax")
+	}
+	*b = (bigValue)(*int)
+	return nil
+}
+
+func (f BigFlag) GetName() string {
+	return f.Name
+}
+
+func (f BigFlag) String() string {
+	fmtString := "%s %v\t%v"
+	if f.Value != nil {
+		fmtString = "%s \"%v\"\t%v"
+	}
+	return fmt.Sprintf(fmtString, prefixedNames(f.Name), f.Value, f.Usage)
+}
+
+func (f BigFlag) Apply(set *flag.FlagSet) {
+	eachName(f.Name, func(name string) {
+		set.Var((*bigValue)(f.Value), f.Name, f.Usage)
+	})
+}
+
+// GlobalBig returns the value of a BigFlag from the global flag set.
+func GlobalBig(ctx *cli.Context, name string) *big.Int {
+	val := ctx.GlobalGeneric(name)
+	if val == nil {
+		return nil
+	}
+	return (*big.Int)(val.(*bigValue))
+}
+
 func prefixFor(name string) (prefix string) {
 	if len(name) == 1 {
 		prefix = "-"
@@ -106,14 +154,6 @@ func prefixedNames(fullName string) (prefixed string) {
 	return
 }
 
-func withEnvHint(envVar, str string) string {
-	envText := ""
-	if envVar != "" {
-		envText = fmt.Sprintf(" [$%s]", strings.Join(strings.Split(envVar, ","), ", $"))
-	}
-	return str + envText
-}
-
 func (self DirectoryFlag) GetName() string {
 	return self.Name
 }

cmd/utils/flags.go

@@ -179,10 +179,10 @@ var (
 		Usage: "Number of CPU threads to use for mining",
 		Value: runtime.NumCPU(),
 	}
-	TargetGasLimitFlag = cli.StringFlag{
+	TargetGasLimitFlag = cli.Uint64Flag{
 		Name:  "targetgaslimit",
 		Usage: "Target gas limit sets the artificial target gas floor for the blocks to mine",
-		Value: params.GenesisGasLimit.String(),
+		Value: params.GenesisGasLimit.Uint64(),
 	}
 	AutoDAGFlag = cli.BoolFlag{
 		Name:  "autodag",
@@ -193,10 +193,10 @@ var (
 		Usage: "Public address for block mining rewards (default = first account created)",
 		Value: "0",
 	}
-	GasPriceFlag = cli.StringFlag{
+	GasPriceFlag = BigFlag{
 		Name:  "gasprice",
 		Usage: "Minimal gas price to accept for mining a transactions",
-		Value: fmt.Sprint(uint64(20 * params.Shannon)),
+		Value: big.NewInt(20 * params.Shannon),
 	}
 	ExtraDataFlag = cli.StringFlag{
 		Name:  "extradata",
@@ -382,15 +382,15 @@ var (
 	}
 
 	// Gas price oracle settings
-	GpoMinGasPriceFlag = cli.StringFlag{
+	GpoMinGasPriceFlag = BigFlag{
 		Name:  "gpomin",
 		Usage: "Minimum suggested gas price",
-		Value: fmt.Sprint(uint64(20 * params.Shannon)),
+		Value: big.NewInt(20 * params.Shannon),
 	}
-	GpoMaxGasPriceFlag = cli.StringFlag{
+	GpoMaxGasPriceFlag = BigFlag{
 		Name:  "gpomax",
 		Usage: "Maximum suggested gas price",
-		Value: fmt.Sprint(uint64(500 * params.Shannon)),
+		Value: big.NewInt(500 * params.Shannon),
 	}
 	GpoFullBlockRatioFlag = cli.IntFlag{
 		Name:  "gpofull",
@@ -741,9 +741,9 @@ func RegisterEthService(ctx *cli.Context, stack *node.Node, extra []byte) {
 		MinerThreads:            ctx.GlobalInt(MinerThreadsFlag.Name),
 		ExtraData:               MakeMinerExtra(extra, ctx),
 		DocRoot:                 ctx.GlobalString(DocRootFlag.Name),
-		GasPrice:                common.String2Big(ctx.GlobalString(GasPriceFlag.Name)),
-		GpoMinGasPrice:          common.String2Big(ctx.GlobalString(GpoMinGasPriceFlag.Name)),
-		GpoMaxGasPrice:          common.String2Big(ctx.GlobalString(GpoMaxGasPriceFlag.Name)),
+		GasPrice:                GlobalBig(ctx, GasPriceFlag.Name),
+		GpoMinGasPrice:          GlobalBig(ctx, GpoMinGasPriceFlag.Name),
+		GpoMaxGasPrice:          GlobalBig(ctx, GpoMaxGasPriceFlag.Name),
 		GpoFullBlockRatio:       ctx.GlobalInt(GpoFullBlockRatioFlag.Name),
 		GpobaseStepDown:         ctx.GlobalInt(GpobaseStepDownFlag.Name),
 		GpobaseStepUp:           ctx.GlobalInt(GpobaseStepUpFlag.Name),
@@ -819,7 +819,7 @@ func RegisterEthStatsService(stack *node.Node, url string) {
 
 // SetupNetwork configures the system for either the main net or some test network.
 func SetupNetwork(ctx *cli.Context) {
-	params.TargetGasLimit = common.String2Big(ctx.GlobalString(TargetGasLimitFlag.Name))
+	params.TargetGasLimit = new(big.Int).SetUint64(ctx.GlobalUint64(TargetGasLimitFlag.Name))
 }
 
 // MakeChainConfig reads the chain configuration from the database in ctx.Datadir.