flag 자체 구현

flagx/commandline.go

@@ -0,0 +1,175 @@
+package flagx
+
+import (
+	"encoding"
+	"flag"
+	"fmt"
+	"os"
+	"strings"
+	"time"
+)
+
+var commandLine = []*flag.FlagSet{
+	flag.NewFlagSet(os.Args[0], flag.ContinueOnError),
+}
+
+func init() {
+	Parse()
+}
+
+func findProperFlagSet(name string) *flag.FlagSet {
+	for _, cl := range commandLine {
+		if cl.Lookup(name) == nil {
+			return cl
+		}
+	}
+	next := flag.NewFlagSet(fmt.Sprintf("%s-%d", os.Args[0], len(commandLine)), flag.ContinueOnError)
+	commandLine = append(commandLine, next)
+	return next
+}
+
+func VisitAll(fn func(*flag.Flag)) {
+	for _, cl := range commandLine {
+		cl.VisitAll(fn)
+	}
+}
+
+// Visit visits the command-line flags in lexicographical order, calling fn
+// for each. It visits only those flags that have been set.
+func Visit(fn func(*flag.Flag)) {
+	for _, cl := range commandLine {
+		cl.Visit(fn)
+	}
+}
+
+func Lookup(name string) *flag.Flag {
+	for _, cl := range commandLine {
+		f := cl.Lookup(name)
+		if f != nil {
+			return f
+		}
+	}
+	return nil
+}
+
+func Set(name, value string) error {
+	for _, cl := range commandLine {
+		if cl.Lookup(name) != nil {
+			return cl.Set(name, value)
+		}
+	}
+	return fmt.Errorf("no such flag -%v", name)
+}
+
+func PrintDefaults() {
+	for _, cl := range commandLine {
+		cl.PrintDefaults()
+	}
+}
+
+func BoolVar(p *bool, name string, value bool, usage string) {
+	findProperFlagSet(name).BoolVar(p, name, value, usage)
+}
+
+func Bool(name string, value bool, usage string) *bool {
+	return findProperFlagSet(name).Bool(name, value, usage)
+}
+
+func IntVar(p *int, name string, value int, usage string) {
+	findProperFlagSet(name).IntVar(p, name, value, usage)
+}
+func Int(name string, value int, usage string) *int {
+	return findProperFlagSet(name).Int(name, value, usage)
+}
+func Int64Var(p *int64, name string, value int64, usage string) {
+	findProperFlagSet(name).Int64Var(p, name, value, usage)
+}
+
+func Int64(name string, value int64, usage string) *int64 {
+	return findProperFlagSet(name).Int64(name, value, usage)
+}
+
+func UintVar(p *uint, name string, value uint, usage string) {
+	findProperFlagSet(name).UintVar(p, name, value, usage)
+}
+
+func Uint(name string, value uint, usage string) *uint {
+	return findProperFlagSet(name).Uint(name, value, usage)
+}
+
+func Uint64Var(p *uint64, name string, value uint64, usage string) {
+	findProperFlagSet(name).Uint64Var(p, name, value, usage)
+}
+
+func Uint64(name string, value uint64, usage string) *uint64 {
+	return findProperFlagSet(name).Uint64(name, value, usage)
+}
+
+func StringVar(p *string, name string, value string, usage string) {
+	findProperFlagSet(name).StringVar(p, name, value, usage)
+}
+
+func String(name string, value string, usage string) *string {
+	return findProperFlagSet(name).String(name, value, usage)
+}
+
+func Float64Var(p *float64, name string, value float64, usage string) {
+	findProperFlagSet(name).Float64Var(p, name, value, usage)
+}
+
+func Float64(name string, value float64, usage string) *float64 {
+	return findProperFlagSet(name).Float64(name, value, usage)
+}
+
+func DurationVar(p *time.Duration, name string, value time.Duration, usage string) {
+	findProperFlagSet(name).DurationVar(p, name, value, usage)
+}
+
+func Duration(name string, value time.Duration, usage string) *time.Duration {
+	return findProperFlagSet(name).Duration(name, value, usage)
+}
+
+func TextVar(p encoding.TextUnmarshaler, name string, value encoding.TextMarshaler, usage string) {
+	findProperFlagSet(name).TextVar(p, name, value, usage)
+}
+func Func(name, usage string, fn func(string) error) {
+	findProperFlagSet(name).Func(name, usage, fn)
+}
+
+func Var(value flag.Value, name string, usage string) {
+	findProperFlagSet(name).Var(value, name, usage)
+}
+
+func Parse() {
+	args := os.Args[1:]
+	for _, cl := range commandLine {
+		if cl.Parsed() {
+			continue
+		}
+
+		var filtered []string
+		cl.VisitAll(func(f *flag.Flag) {
+			for _, arg := range args {
+				test := strings.TrimLeft(arg, "-")
+				if test == f.Name || strings.HasPrefix(test, f.Name+"=") {
+					filtered = append(filtered, arg)
+					break
+				}
+			}
+		})
+		cl.Parse(filtered)
+	}
+}
+
+func Parsed() bool {
+	for _, cl := range commandLine {
+		if !cl.Parsed() {
+			return false
+		}
+	}
+	return true
+}
+
+func NewFlagSet(name string, errorHandling flag.ErrorHandling) *flag.FlagSet {
+	return flag.NewFlagSet(name, errorHandling)
+}