blob: d36c8411786136c6f671cf67ee88f60999fae637 [file] [log] [blame]
package flags
import (
"reflect"
"strings"
"syscall"
)
// Set the value of an option to the specified value. An error will be returned
// if the specified value could not be converted to the corresponding option
// value type.
func (option *Option) set(value *string) error {
option.isSet = true
if option.isFunc() {
return option.call(value)
} else if value != nil {
return convert(*value, option.value, option.tag)
}
return convert("", option.value, option.tag)
}
func (option *Option) canCli() bool {
return option.ShortName != 0 || len(option.LongName) != 0
}
func (option *Option) canArgument() bool {
if u := option.isUnmarshaler(); u != nil {
return true
}
return !option.isBool()
}
func (option *Option) emptyValue() reflect.Value {
tp := option.value.Type()
if tp.Kind() == reflect.Map {
return reflect.MakeMap(tp)
}
return reflect.Zero(tp)
}
func (option *Option) empty() {
if !option.isFunc() {
option.value.Set(option.emptyValue())
}
}
func (option *Option) clearDefault() {
usedDefault := option.Default
if envKey := option.EnvDefaultKey; envKey != "" {
// os.Getenv() makes no distinction between undefined and
// empty values, so we use syscall.Getenv()
if value, ok := syscall.Getenv(envKey); ok {
if option.EnvDefaultDelim != "" {
usedDefault = strings.Split(value,
option.EnvDefaultDelim)
} else {
usedDefault = []string{value}
}
}
}
if len(usedDefault) > 0 {
option.empty()
for _, d := range usedDefault {
option.set(&d)
}
} else {
tp := option.value.Type()
switch tp.Kind() {
case reflect.Map:
if option.value.IsNil() {
option.empty()
}
case reflect.Slice:
if option.value.IsNil() {
option.empty()
}
}
}
}
func (option *Option) valueIsDefault() bool {
// Check if the value of the option corresponds to its
// default value
emptyval := option.emptyValue()
checkvalptr := reflect.New(emptyval.Type())
checkval := reflect.Indirect(checkvalptr)
checkval.Set(emptyval)
if len(option.Default) != 0 {
for _, v := range option.Default {
convert(v, checkval, option.tag)
}
}
return reflect.DeepEqual(option.value.Interface(), checkval.Interface())
}
func (option *Option) isUnmarshaler() Unmarshaler {
v := option.value
for {
if !v.CanInterface() {
break
}
i := v.Interface()
if u, ok := i.(Unmarshaler); ok {
return u
}
if !v.CanAddr() {
break
}
v = v.Addr()
}
return nil
}
func (option *Option) isBool() bool {
tp := option.value.Type()
for {
switch tp.Kind() {
case reflect.Bool:
return true
case reflect.Slice:
return (tp.Elem().Kind() == reflect.Bool)
case reflect.Func:
return tp.NumIn() == 0
case reflect.Ptr:
tp = tp.Elem()
default:
return false
}
}
}
func (option *Option) isFunc() bool {
return option.value.Type().Kind() == reflect.Func
}
func (option *Option) call(value *string) error {
var retval []reflect.Value
if value == nil {
retval = option.value.Call(nil)
} else {
tp := option.value.Type().In(0)
val := reflect.New(tp)
val = reflect.Indirect(val)
if err := convert(*value, val, option.tag); err != nil {
return err
}
retval = option.value.Call([]reflect.Value{val})
}
if len(retval) == 1 && retval[0].Type() == reflect.TypeOf((*error)(nil)).Elem() {
if retval[0].Interface() == nil {
return nil
}
return retval[0].Interface().(error)
}
return nil
}