WIP: flagcodec: enable flag normalization

Signed-off-by: Francesco Romani <[email protected]>

pkg/flagcodec/flagcodec.go

@@ -38,9 +38,10 @@ type Val struct {
 }
 
 type Flags struct {
-	command string
-	args    map[string]Val
-	keys    []string
+	command         string
+	args            map[string]Val
+	keys            []string
+	processFlagName func(string) string
 }
 
 // ParseArgvKeyValue parses a clean (trimmed) argv whose components
@@ -67,8 +68,9 @@ func ParseArgvKeyValue(args []string) *Flags {
 // The command is supplied explicitely as parameter.
 func ParseArgvKeyValueWithCommand(command string, args []string) *Flags {
 	ret := &Flags{
-		command: command,
-		args:    make(map[string]Val),
+		command:         command,
+		args:            make(map[string]Val),
+		processFlagName: func(v string) string { return v },
 	}
 	for _, arg := range args {
 		fields := strings.SplitN(arg, "=", 2)
@@ -81,6 +83,29 @@ func ParseArgvKeyValueWithCommand(command string, args []string) *Flags {
 	return ret
 }
 
+func normalizeFlagName(v string) string {
+	if len(v) == 3 && v[0] == '-' && v[1] == '-' {
+		// single char, double dash flag (ugly?), fix it
+		return v[1:]
+	}
+	// everything else pass through silently
+	return v
+}
+
+// EnableNormalizeFlags optionally enables flag normalization.
+// The canonical representation of flags in this package is:
+// * single-dash for one-char flags (-v, -h)
+// * double-dash for multi-char flags (--foo, --long-option)
+// pflag allows one-char to have one or two dashes. For flagcodec
+// these were different options. When normalization is enabled,
+// though, all flag names are processed to adhere to the canonical
+// representation, so flagcodec will treat `--v` and `-v` to
+// be the same flag. Since this is possibly breaking change,
+// this treatment is opt-in.
+func (fl *Flags) EnableNormalizeFlags() {
+	fl.processFlagName = normalizeFlagName
+}
+
 func (fl *Flags) recordFlag(name string) {
 	if _, ok := fl.args[name]; !ok {
 		fl.keys = append(fl.keys, name)
@@ -99,13 +124,15 @@ func (fl *Flags) forgetFlag(name string) {
 }
 
 func (fl *Flags) SetToggle(name string) {
+	name = fl.processFlagName(name)
 	fl.recordFlag(name)
 	fl.args[name] = Val{
 		Kind: FlagToggle,
 	}
 }
 
 func (fl *Flags) SetOption(name, data string) {
+	name = fl.processFlagName(name)
 	fl.recordFlag(name)
 	fl.args[name] = Val{
 		Kind: FlagOption,
@@ -114,6 +141,7 @@ func (fl *Flags) SetOption(name, data string) {
 }
 
 func (fl *Flags) Delete(name string) {
+	name = fl.processFlagName(name)
 	fl.forgetFlag(name)
 	delete(fl.args, name)
 }
@@ -139,6 +167,7 @@ func (fl *Flags) Argv() []string {
 }
 
 func (fl *Flags) GetFlag(name string) (Val, bool) {
+	name = fl.processFlagName(name)
 	if val, ok := fl.args[name]; ok {
 		return val, ok
 	}