prometheus/vendor/gopkg.in/alecthomas/kingpin.v2/args.go
2017-06-20 17:37:40 +02:00

119 lines
2.4 KiB
Go

package kingpin
import "fmt"
type argGroup struct {
args []*ArgClause
}
func newArgGroup() *argGroup {
return &argGroup{}
}
func (a *argGroup) have() bool {
return len(a.args) > 0
}
// GetArg gets an argument definition.
//
// This allows existing arguments to be modified after definition but before parsing. Useful for
// modular applications.
func (a *argGroup) GetArg(name string) *ArgClause {
for _, arg := range a.args {
if arg.name == name {
return arg
}
}
return nil
}
func (a *argGroup) Arg(name, help string) *ArgClause {
arg := newArg(name, help)
a.args = append(a.args, arg)
return arg
}
func (a *argGroup) init() error {
required := 0
seen := map[string]struct{}{}
previousArgMustBeLast := false
for i, arg := range a.args {
if previousArgMustBeLast {
return fmt.Errorf("Args() can't be followed by another argument '%s'", arg.name)
}
if arg.consumesRemainder() {
previousArgMustBeLast = true
}
if _, ok := seen[arg.name]; ok {
return fmt.Errorf("duplicate argument '%s'", arg.name)
}
seen[arg.name] = struct{}{}
if arg.required && required != i {
return fmt.Errorf("required arguments found after non-required")
}
if arg.required {
required++
}
if err := arg.init(); err != nil {
return err
}
}
return nil
}
type ArgClause struct {
actionMixin
parserMixin
name string
help string
defaultValues []string
required bool
}
func newArg(name, help string) *ArgClause {
a := &ArgClause{
name: name,
help: help,
}
return a
}
func (a *ArgClause) consumesRemainder() bool {
if r, ok := a.value.(remainderArg); ok {
return r.IsCumulative()
}
return false
}
// Required arguments must be input by the user. They can not have a Default() value provided.
func (a *ArgClause) Required() *ArgClause {
a.required = true
return a
}
// Default values for this argument. They *must* be parseable by the value of the argument.
func (a *ArgClause) Default(values ...string) *ArgClause {
a.defaultValues = values
return a
}
func (a *ArgClause) Action(action Action) *ArgClause {
a.addAction(action)
return a
}
func (a *ArgClause) PreAction(action Action) *ArgClause {
a.addPreAction(action)
return a
}
func (a *ArgClause) init() error {
if a.required && len(a.defaultValues) > 0 {
return fmt.Errorf("required argument '%s' with unusable default value", a.name)
}
if a.value == nil {
return fmt.Errorf("no parser defined for arg '%s'", a.name)
}
return nil
}