syncthing/github.com/jessevdk/go-flags/group_private.go
2013-12-23 11:18:46 -05:00

264 lines
5.5 KiB
Go

package flags
import (
"reflect"
"unicode/utf8"
"unsafe"
)
type scanHandler func(reflect.Value, *reflect.StructField) (bool, error)
func newGroup(shortDescription string, longDescription string, data interface{}) *Group {
return &Group{
ShortDescription: shortDescription,
LongDescription: longDescription,
data: data,
}
}
func (g *Group) optionByName(name string, namematch func(*Option, string) bool) *Option {
prio := 0
var retopt *Option
for _, opt := range g.options {
if namematch != nil && namematch(opt, name) && prio < 4 {
retopt = opt
prio = 4
}
if name == opt.field.Name && prio < 3 {
retopt = opt
prio = 3
}
if name == opt.LongName && prio < 2 {
retopt = opt
prio = 2
}
if opt.ShortName != 0 && name == string(opt.ShortName) && prio < 1 {
retopt = opt
prio = 1
}
}
return retopt
}
func (g *Group) storeDefaults() {
for _, option := range g.options {
// First. empty out the value
if len(option.Default) > 0 {
option.clear()
}
for _, d := range option.Default {
option.set(&d)
}
if !option.value.CanSet() {
continue
}
option.defaultValue = reflect.ValueOf(option.value.Interface())
}
}
func (g *Group) eachGroup(f func(*Group)) {
f(g)
for _, gg := range g.groups {
gg.eachGroup(f)
}
}
func (g *Group) scanStruct(realval reflect.Value, sfield *reflect.StructField, handler scanHandler) error {
stype := realval.Type()
if sfield != nil {
if ok, err := handler(realval, sfield); err != nil {
return err
} else if ok {
return nil
}
}
for i := 0; i < stype.NumField(); i++ {
field := stype.Field(i)
// PkgName is set only for non-exported fields, which we ignore
if field.PkgPath != "" {
continue
}
mtag := newMultiTag(string(field.Tag))
if err := mtag.Parse(); err != nil {
return err
}
// Skip fields with the no-flag tag
if mtag.Get("no-flag") != "" {
continue
}
// Dive deep into structs or pointers to structs
kind := field.Type.Kind()
fld := realval.Field(i)
if kind == reflect.Struct {
if err := g.scanStruct(fld, &field, handler); err != nil {
return err
}
} else if kind == reflect.Ptr && field.Type.Elem().Kind() == reflect.Struct {
if fld.IsNil() {
fld.Set(reflect.New(fld.Type().Elem()))
}
if err := g.scanStruct(reflect.Indirect(fld), &field, handler); err != nil {
return err
}
}
longname := mtag.Get("long")
shortname := mtag.Get("short")
// Need at least either a short or long name
if longname == "" && shortname == "" && mtag.Get("ini-name") == "" {
continue
}
short := rune(0)
rc := utf8.RuneCountInString(shortname)
if rc > 1 {
return newErrorf(ErrShortNameTooLong,
"short names can only be 1 character long, not `%s'",
shortname)
} else if rc == 1 {
short, _ = utf8.DecodeRuneInString(shortname)
}
description := mtag.Get("description")
def := mtag.GetMany("default")
optionalValue := mtag.GetMany("optional-value")
valueName := mtag.Get("value-name")
defaultMask := mtag.Get("default-mask")
optional := (mtag.Get("optional") != "")
required := (mtag.Get("required") != "")
option := &Option{
Description: description,
ShortName: short,
LongName: longname,
Default: def,
OptionalArgument: optional,
OptionalValue: optionalValue,
Required: required,
ValueName: valueName,
DefaultMask: defaultMask,
field: field,
value: realval.Field(i),
tag: mtag,
}
g.options = append(g.options, option)
}
return nil
}
func (g *Group) checkForDuplicateFlags() *Error {
shortNames := make(map[rune]*Option)
longNames := make(map[string]*Option)
var duplicateError *Error
g.eachGroup(func(g *Group) {
for _, option := range g.options {
if option.LongName != "" {
if otherOption, ok := longNames[option.LongName]; ok {
duplicateError = newErrorf(ErrDuplicatedFlag, "option `%s' uses the same long name as option `%s'", option, otherOption)
return
}
longNames[option.LongName] = option
}
if option.ShortName != 0 {
if otherOption, ok := shortNames[option.ShortName]; ok {
duplicateError = newErrorf(ErrDuplicatedFlag, "option `%s' uses the same short name as option `%s'", option, otherOption)
return
}
shortNames[option.ShortName] = option
}
}
})
return duplicateError
}
func (g *Group) scanSubGroupHandler(realval reflect.Value, sfield *reflect.StructField) (bool, error) {
mtag := newMultiTag(string(sfield.Tag))
if err := mtag.Parse(); err != nil {
return true, err
}
subgroup := mtag.Get("group")
if len(subgroup) != 0 {
ptrval := reflect.NewAt(realval.Type(), unsafe.Pointer(realval.UnsafeAddr()))
description := mtag.Get("description")
if _, err := g.AddGroup(subgroup, description, ptrval.Interface()); err != nil {
return true, err
}
return true, nil
}
return false, nil
}
func (g *Group) scanType(handler scanHandler) error {
// Get all the public fields in the data struct
ptrval := reflect.ValueOf(g.data)
if ptrval.Type().Kind() != reflect.Ptr {
panic(ErrNotPointerToStruct)
}
stype := ptrval.Type().Elem()
if stype.Kind() != reflect.Struct {
panic(ErrNotPointerToStruct)
}
realval := reflect.Indirect(ptrval)
if err := g.scanStruct(realval, nil, handler); err != nil {
return err
}
if err := g.checkForDuplicateFlags(); err != nil {
return err
}
return nil
}
func (g *Group) scan() error {
return g.scanType(g.scanSubGroupHandler)
}
func (g *Group) groupByName(name string) *Group {
if len(name) == 0 {
return g
}
return g.Find(name)
}