syncthing/vendor/github.com/AudriusButkevicius/cli/flag.go

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package cli
import (
"flag"
"fmt"
"os"
"strconv"
"strings"
)
// This flag enables bash-completion for all commands and subcommands
var BashCompletionFlag = BoolFlag{
Name: "generate-bash-completion",
}
// This flag prints the version for the application
var VersionFlag = BoolFlag{
Name: "version, v",
Usage: "print the version",
}
// This flag prints the help for all commands and subcommands
var HelpFlag = BoolFlag{
Name: "help, h",
Usage: "show help",
}
// Flag is a common interface related to parsing flags in cli.
// For more advanced flag parsing techniques, it is recomended that
// this interface be implemented.
type Flag interface {
fmt.Stringer
// Apply Flag settings to the given flag set
Apply(*flag.FlagSet)
getName() string
}
func flagSet(name string, flags []Flag) *flag.FlagSet {
set := flag.NewFlagSet(name, flag.ContinueOnError)
for _, f := range flags {
f.Apply(set)
}
return set
}
func eachName(longName string, fn func(string)) {
parts := strings.Split(longName, ",")
for _, name := range parts {
name = strings.Trim(name, " ")
fn(name)
}
}
// Generic is a generic parseable type identified by a specific flag
type Generic interface {
Set(value string) error
String() string
}
// GenericFlag is the flag type for types implementing Generic
type GenericFlag struct {
Name string
Value Generic
Usage string
EnvVar string
}
func (f GenericFlag) String() string {
return withEnvHint(f.EnvVar, fmt.Sprintf("%s%s %v\t`%v` %s", prefixFor(f.Name), f.Name, f.Value, "-"+f.Name+" option -"+f.Name+" option", f.Usage))
}
func (f GenericFlag) Apply(set *flag.FlagSet) {
val := f.Value
if f.EnvVar != "" {
if envVal := os.Getenv(f.EnvVar); envVal != "" {
val.Set(envVal)
}
}
eachName(f.Name, func(name string) {
set.Var(f.Value, name, f.Usage)
})
}
func (f GenericFlag) getName() string {
return f.Name
}
type StringSlice []string
func (f *StringSlice) Set(value string) error {
*f = append(*f, value)
return nil
}
func (f *StringSlice) String() string {
return fmt.Sprintf("%s", *f)
}
func (f *StringSlice) Value() []string {
return *f
}
type StringSliceFlag struct {
Name string
Value *StringSlice
Usage string
EnvVar string
}
func (f StringSliceFlag) String() string {
firstName := strings.Trim(strings.Split(f.Name, ",")[0], " ")
pref := prefixFor(firstName)
return withEnvHint(f.EnvVar, fmt.Sprintf("%s '%v'\t%v", prefixedNames(f.Name), pref+firstName+" option "+pref+firstName+" option", f.Usage))
}
func (f StringSliceFlag) Apply(set *flag.FlagSet) {
if f.EnvVar != "" {
if envVal := os.Getenv(f.EnvVar); envVal != "" {
newVal := &StringSlice{}
for _, s := range strings.Split(envVal, ",") {
newVal.Set(s)
}
f.Value = newVal
}
}
eachName(f.Name, func(name string) {
set.Var(f.Value, name, f.Usage)
})
}
func (f StringSliceFlag) getName() string {
return f.Name
}
type IntSlice []int
func (f *IntSlice) Set(value string) error {
tmp, err := strconv.Atoi(value)
if err != nil {
return err
} else {
*f = append(*f, tmp)
}
return nil
}
func (f *IntSlice) String() string {
return fmt.Sprintf("%d", *f)
}
func (f *IntSlice) Value() []int {
return *f
}
type IntSliceFlag struct {
Name string
Value *IntSlice
Usage string
EnvVar string
}
func (f IntSliceFlag) String() string {
firstName := strings.Trim(strings.Split(f.Name, ",")[0], " ")
pref := prefixFor(firstName)
return withEnvHint(f.EnvVar, fmt.Sprintf("%s '%v'\t%v", prefixedNames(f.Name), pref+firstName+" option "+pref+firstName+" option", f.Usage))
}
func (f IntSliceFlag) Apply(set *flag.FlagSet) {
if f.EnvVar != "" {
if envVal := os.Getenv(f.EnvVar); envVal != "" {
newVal := &IntSlice{}
for _, s := range strings.Split(envVal, ",") {
err := newVal.Set(s)
if err != nil {
fmt.Fprintf(os.Stderr, err.Error())
}
}
f.Value = newVal
}
}
eachName(f.Name, func(name string) {
set.Var(f.Value, name, f.Usage)
})
}
func (f IntSliceFlag) getName() string {
return f.Name
}
type BoolFlag struct {
Name string
Usage string
EnvVar string
}
func (f BoolFlag) String() string {
return withEnvHint(f.EnvVar, fmt.Sprintf("%s\t%v", prefixedNames(f.Name), f.Usage))
}
func (f BoolFlag) Apply(set *flag.FlagSet) {
val := false
if f.EnvVar != "" {
if envVal := os.Getenv(f.EnvVar); envVal != "" {
envValBool, err := strconv.ParseBool(envVal)
if err == nil {
val = envValBool
}
}
}
eachName(f.Name, func(name string) {
set.Bool(name, val, f.Usage)
})
}
func (f BoolFlag) getName() string {
return f.Name
}
type BoolTFlag struct {
Name string
Usage string
EnvVar string
}
func (f BoolTFlag) String() string {
return withEnvHint(f.EnvVar, fmt.Sprintf("%s\t%v", prefixedNames(f.Name), f.Usage))
}
func (f BoolTFlag) Apply(set *flag.FlagSet) {
val := true
if f.EnvVar != "" {
if envVal := os.Getenv(f.EnvVar); envVal != "" {
envValBool, err := strconv.ParseBool(envVal)
if err == nil {
val = envValBool
}
}
}
eachName(f.Name, func(name string) {
set.Bool(name, val, f.Usage)
})
}
func (f BoolTFlag) getName() string {
return f.Name
}
type StringFlag struct {
Name string
Value string
Usage string
EnvVar string
}
func (f StringFlag) String() string {
var fmtString string
fmtString = "%s %v\t%v"
if len(f.Value) > 0 {
fmtString = "%s '%v'\t%v"
} else {
fmtString = "%s %v\t%v"
}
return withEnvHint(f.EnvVar, fmt.Sprintf(fmtString, prefixedNames(f.Name), f.Value, f.Usage))
}
func (f StringFlag) Apply(set *flag.FlagSet) {
if f.EnvVar != "" {
if envVal := os.Getenv(f.EnvVar); envVal != "" {
f.Value = envVal
}
}
eachName(f.Name, func(name string) {
set.String(name, f.Value, f.Usage)
})
}
func (f StringFlag) getName() string {
return f.Name
}
type IntFlag struct {
Name string
Value int
Usage string
EnvVar string
}
func (f IntFlag) String() string {
return withEnvHint(f.EnvVar, fmt.Sprintf("%s '%v'\t%v", prefixedNames(f.Name), f.Value, f.Usage))
}
func (f IntFlag) Apply(set *flag.FlagSet) {
if f.EnvVar != "" {
if envVal := os.Getenv(f.EnvVar); envVal != "" {
envValInt, err := strconv.ParseUint(envVal, 10, 64)
if err == nil {
f.Value = int(envValInt)
}
}
}
eachName(f.Name, func(name string) {
set.Int(name, f.Value, f.Usage)
})
}
func (f IntFlag) getName() string {
return f.Name
}
type Float64Flag struct {
Name string
Value float64
Usage string
EnvVar string
}
func (f Float64Flag) String() string {
return withEnvHint(f.EnvVar, fmt.Sprintf("%s '%v'\t%v", prefixedNames(f.Name), f.Value, f.Usage))
}
func (f Float64Flag) Apply(set *flag.FlagSet) {
if f.EnvVar != "" {
if envVal := os.Getenv(f.EnvVar); envVal != "" {
envValFloat, err := strconv.ParseFloat(envVal, 10)
if err == nil {
f.Value = float64(envValFloat)
}
}
}
eachName(f.Name, func(name string) {
set.Float64(name, f.Value, f.Usage)
})
}
func (f Float64Flag) getName() string {
return f.Name
}
func prefixFor(name string) (prefix string) {
if len(name) == 1 {
prefix = "-"
} else {
prefix = "--"
}
return
}
func prefixedNames(fullName string) (prefixed string) {
parts := strings.Split(fullName, ",")
for i, name := range parts {
name = strings.Trim(name, " ")
prefixed += prefixFor(name) + name
if i < len(parts)-1 {
prefixed += ", "
}
}
return
}
func withEnvHint(envVar, str string) string {
envText := ""
if envVar != "" {
envText = fmt.Sprintf(" [$%s]", envVar)
}
return str + envText
}