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package flags
import (
"bytes"
"fmt"
"reflect"
"strings"
"syscall"
"unicode/utf8"
)
// Option flag information. Contains a description of the option, short and
// long name as well as a default value and whether an argument for this
// flag is optional.
type Option struct {
// The description of the option flag. This description is shown
// automatically in the built-in help.
Description string
// The short name of the option (a single character). If not 0, the
// option flag can be 'activated' using -<ShortName>. Either ShortName
// or LongName needs to be non-empty.
ShortName rune
// The long name of the option. If not "", the option flag can be
// activated using --<LongName>. Either ShortName or LongName needs
// to be non-empty.
LongName string
// The default value of the option.
Default []string
// The optional environment default value key name.
EnvDefaultKey string
// The optional delimiter string for EnvDefaultKey values.
EnvDefaultDelim string
// If true, specifies that the argument to an option flag is optional.
// When no argument to the flag is specified on the command line, the
// value of OptionalValue will be set in the field this option represents.
// This is only valid for non-boolean options.
OptionalArgument bool
// The optional value of the option. The optional value is used when
// the option flag is marked as having an OptionalArgument. This means
// that when the flag is specified, but no option argument is given,
// the value of the field this option represents will be set to
// OptionalValue. This is only valid for non-boolean options.
OptionalValue []string
// If true, the option _must_ be specified on the command line. If the
// option is not specified, the parser will generate an ErrRequired type
// error.
Required bool
// A name for the value of an option shown in the Help as --flag [ValueName]
ValueName string
// A mask value to show in the help instead of the default value. This
// is useful for hiding sensitive information in the help, such as
// passwords.
DefaultMask string
// If non empty, only a certain set of values is allowed for an option.
Choices []string
// If true, the option is not displayed in the help or man page
Hidden bool
// The group which the option belongs to
group *Group
// The struct field which the option represents.
field reflect.StructField
// The struct field value which the option represents.
value reflect.Value
// Determines if the option will be always quoted in the INI output
iniQuote bool
tag multiTag
isSet bool
isSetDefault bool
preventDefault bool
defaultLiteral string
}
// LongNameWithNamespace returns the option's long name with the group namespaces
// prepended by walking up the option's group tree. Namespaces and the long name
// itself are separated by the parser's namespace delimiter. If the long name is
// empty an empty string is returned.
func (option *Option) LongNameWithNamespace() string {
if len(option.LongName) == 0 {
return ""
}
// fetch the namespace delimiter from the parser which is always at the
// end of the group hierarchy
namespaceDelimiter := ""
g := option.group
for {
if p, ok := g.parent.(*Parser); ok {
namespaceDelimiter = p.NamespaceDelimiter
break
}
switch i := g.parent.(type) {
case *Command:
g = i.Group
case *Group:
g = i
}
}
// concatenate long name with namespace
longName := option.LongName
g = option.group
for g != nil {
if g.Namespace != "" {
longName = g.Namespace + namespaceDelimiter + longName
}
switch i := g.parent.(type) {
case *Command:
g = i.Group
case *Group:
g = i
case *Parser:
g = nil
}
}
return longName
}
// String converts an option to a human friendly readable string describing the
// option.
func (option *Option) String() string {
var s string
var short string
if option.ShortName != 0 {
data := make([]byte, utf8.RuneLen(option.ShortName))
utf8.EncodeRune(data, option.ShortName)
short = string(data)
if len(option.LongName) != 0 {
s = fmt.Sprintf("%s%s, %s%s",
string(defaultShortOptDelimiter), short,
defaultLongOptDelimiter, option.LongNameWithNamespace())
} else {
s = fmt.Sprintf("%s%s", string(defaultShortOptDelimiter), short)
}
} else if len(option.LongName) != 0 {
s = fmt.Sprintf("%s%s", defaultLongOptDelimiter, option.LongNameWithNamespace())
}
return s
}
// Value returns the option value as an interface{}.
func (option *Option) Value() interface{} {
return option.value.Interface()
}
// Field returns the reflect struct field of the option.
func (option *Option) Field() reflect.StructField {
return option.field
}
// IsSet returns true if option has been set
func (option *Option) IsSet() bool {
return option.isSet
}
// IsSetDefault returns true if option has been set via the default option tag
func (option *Option) IsSetDefault() bool {
return option.isSetDefault
}
// 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 {
kind := option.value.Type().Kind()
if (kind == reflect.Map || kind == reflect.Slice) && !option.isSet {
option.empty()
}
option.isSet = true
option.preventDefault = true
if len(option.Choices) != 0 {
found := false
for _, choice := range option.Choices {
if choice == *value {
found = true
break
}
}
if !found {
allowed := strings.Join(option.Choices[0:len(option.Choices)-1], ", ")
if len(option.Choices) > 1 {
allowed += " or " + option.Choices[len(option.Choices)-1]
}
return newErrorf(ErrInvalidChoice,
"Invalid value `%s' for option `%s'. Allowed values are: %s",
*value, option, allowed)
}
}
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}
}
}
}
option.isSetDefault = true
if len(usedDefault) > 0 {
option.empty()
for _, d := range usedDefault {
option.set(&d)
option.isSetDefault = true
}
} 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.Slice, reflect.Ptr:
tp = tp.Elem()
case reflect.Bool:
return true
case reflect.Func:
return tp.NumIn() == 0
default:
return false
}
}
}
func (option *Option) isSignedNumber() bool {
tp := option.value.Type()
for {
switch tp.Kind() {
case reflect.Slice, reflect.Ptr:
tp = tp.Elem()
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Float32, reflect.Float64:
return true
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
}
func (option *Option) updateDefaultLiteral() {
defs := option.Default
def := ""
if len(defs) == 0 && option.canArgument() {
var showdef bool
switch option.field.Type.Kind() {
case reflect.Func, reflect.Ptr:
showdef = !option.value.IsNil()
case reflect.Slice, reflect.String, reflect.Array:
showdef = option.value.Len() > 0
case reflect.Map:
showdef = !option.value.IsNil() && option.value.Len() > 0
default:
zeroval := reflect.Zero(option.field.Type)
showdef = !reflect.DeepEqual(zeroval.Interface(), option.value.Interface())
}
if showdef {
def, _ = convertToString(option.value, option.tag)
}
} else if len(defs) != 0 {
l := len(defs) - 1
for i := 0; i < l; i++ {
def += quoteIfNeeded(defs[i]) + ", "
}
def += quoteIfNeeded(defs[l])
}
option.defaultLiteral = def
}
func (option *Option) shortAndLongName() string {
ret := &bytes.Buffer{}
if option.ShortName != 0 {
ret.WriteRune(defaultShortOptDelimiter)
ret.WriteRune(option.ShortName)
}
if len(option.LongName) != 0 {
if option.ShortName != 0 {
ret.WriteRune('/')
}
ret.WriteString(option.LongName)
}
return ret.String()
}