path: root/vendor/gopkg.in/urfave/cli.v1/flag.go

package cli

import (
    "flag"
    "fmt"
    "reflect"
    "runtime"
    "strconv"
    "strings"
    "syscall"
    "time"
)

const defaultPlaceholder = "value"

// BashCompletionFlag enables bash-completion for all commands and subcommands
var BashCompletionFlag Flag = BoolFlag{
    Name:   "generate-bash-completion",
    Hidden: true,
}

// VersionFlag prints the version for the application
var VersionFlag Flag = BoolFlag{
    Name:  "version, v",
    Usage: "print the version",
}

// HelpFlag prints the help for all commands and subcommands
// Set to the zero value (BoolFlag{}) to disable flag -- keeps subcommand
// unless HideHelp is set to true)
var HelpFlag Flag = BoolFlag{
    Name:  "help, h",
    Usage: "show help",
}

// FlagStringer converts a flag definition to a string. This is used by help
// to display a flag.
var FlagStringer FlagStringFunc = stringifyFlag

// FlagsByName is a slice of Flag.
type FlagsByName []Flag

func (f FlagsByName) Len() int {
    return len(f)
}

func (f FlagsByName) Less(i, j int) bool {
    return f[i].GetName() < f[j].GetName()
}

func (f FlagsByName) Swap(i, j int) {
    f[i], f[j] = f[j], f[i]
}

// Flag is a common interface related to parsing flags in cli.
// For more advanced flag parsing techniques, it is recommended that
// this interface be implemented.
type Flag interface {
    fmt.Stringer
    // Apply Flag settings to the given flag set
    Apply(*flag.FlagSet)
    GetName() string
}

// errorableFlag is an interface that allows us to return errors during apply
// it allows flags defined in this library to return errors in a fashion backwards compatible
// TODO remove in v2 and modify the existing Flag interface to return errors
type errorableFlag interface {
    Flag

    ApplyWithError(*flag.FlagSet) error
}

func flagSet(name string, flags []Flag) (*flag.FlagSet, error) {
    set := flag.NewFlagSet(name, flag.ContinueOnError)

    for _, f := range flags {
        //TODO remove in v2 when errorableFlag is removed
        if ef, ok := f.(errorableFlag); ok {
            if err := ef.ApplyWithError(set); err != nil {
                return nil, err
            }
        } else {
            f.Apply(set)
        }
    }
    return set, nil
}

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
}

// Apply takes the flagset and calls Set on the generic flag with the value
// provided by the user for parsing by the flag
// Ignores parsing errors
func (f GenericFlag) Apply(set *flag.FlagSet) {
    f.ApplyWithError(set)
}

// ApplyWithError takes the flagset and calls Set on the generic flag with the value
// provided by the user for parsing by the flag
func (f GenericFlag) ApplyWithError(set *flag.FlagSet) error {
    val := f.Value
    if f.EnvVar != "" {
        for _, envVar := range strings.Split(f.EnvVar, ",") {
            envVar = strings.TrimSpace(envVar)
            if envVal, ok := syscall.Getenv(envVar); ok {
                if err := val.Set(envVal); err != nil {
                    return fmt.Errorf("could not parse %s as value for flag %s: %s", envVal, f.Name, err)
                }
                break
            }
        }
    }

    eachName(f.Name, func(name string) {
        set.Var(f.Value, name, f.Usage)
    })

    return nil
}

// StringSlice is an opaque type for []string to satisfy flag.Value and flag.Getter
type StringSlice []string

// Set appends the string value to the list of values
func (f *StringSlice) Set(value string) error {
    *f = append(*f, value)
    return nil
}

// String returns a readable representation of this value (for usage defaults)
func (f *StringSlice) String() string {
    return fmt.Sprintf("%s", *f)
}

// Value returns the slice of strings set by this flag
func (f *StringSlice) Value() []string {
    return *f
}

// Get returns the slice of strings set by this flag
func (f *StringSlice) Get() interface{} {
    return *f
}

// Apply populates the flag given the flag set and environment
// Ignores errors
func (f StringSliceFlag) Apply(set *flag.FlagSet) {
    f.ApplyWithError(set)
}

// ApplyWithError populates the flag given the flag set and environment
func (f StringSliceFlag) ApplyWithError(set *flag.FlagSet) error {
    if f.EnvVar != "" {
        for _, envVar := range strings.Split(f.EnvVar, ",") {
            envVar = strings.TrimSpace(envVar)
            if envVal, ok := syscall.Getenv(envVar); ok {
                newVal := &StringSlice{}
                for _, s := range strings.Split(envVal, ",") {
                    s = strings.TrimSpace(s)
                    if err := newVal.Set(s); err != nil {
                        return fmt.Errorf("could not parse %s as string value for flag %s: %s", envVal, f.Name, err)
                    }
                }
                f.Value = newVal
                break
            }
        }
    }

    eachName(f.Name, func(name string) {
        if f.Value == nil {
            f.Value = &StringSlice{}
        }
        set.Var(f.Value, name, f.Usage)
    })

    return nil
}

// IntSlice is an opaque type for []int to satisfy flag.Value and flag.Getter
type IntSlice []int

// Set parses the value into an integer and appends it to the list of values
func (f *IntSlice) Set(value string) error {
    tmp, err := strconv.Atoi(value)
    if err != nil {
        return err
    }
    *f = append(*f, tmp)
    return nil
}

// String returns a readable representation of this value (for usage defaults)
func (f *IntSlice) String() string {
    return fmt.Sprintf("%#v", *f)
}

// Value returns the slice of ints set by this flag
func (f *IntSlice) Value() []int {
    return *f
}

// Get returns the slice of ints set by this flag
func (f *IntSlice) Get() interface{} {
    return *f
}

// Apply populates the flag given the flag set and environment
// Ignores errors
func (f IntSliceFlag) Apply(set *flag.FlagSet) {
    f.ApplyWithError(set)
}

// ApplyWithError populates the flag given the flag set and environment
func (f IntSliceFlag) ApplyWithError(set *flag.FlagSet) error {
    if f.EnvVar != "" {
        for _, envVar := range strings.Split(f.EnvVar, ",") {
            envVar = strings.TrimSpace(envVar)
            if envVal, ok := syscall.Getenv(envVar); ok {
                newVal := &IntSlice{}
                for _, s := range strings.Split(envVal, ",") {
                    s = strings.TrimSpace(s)
                    if err := newVal.Set(s); err != nil {
                        return fmt.Errorf("could not parse %s as int slice value for flag %s: %s", envVal, f.Name, err)
                    }
                }
                f.Value = newVal
                break
            }
        }
    }

    eachName(f.Name, func(name string) {
        if f.Value == nil {
            f.Value = &IntSlice{}
        }
        set.Var(f.Value, name, f.Usage)
    })

    return nil
}

// Int64Slice is an opaque type for []int to satisfy flag.Value and flag.Getter
type Int64Slice []int64

// Set parses the value into an integer and appends it to the list of values
func (f *Int64Slice) Set(value string) error {
    tmp, err := strconv.ParseInt(value, 10, 64)
    if err != nil {
        return err
    }
    *f = append(*f, tmp)
    return nil
}

// String returns a readable representation of this value (for usage defaults)
func (f *Int64Slice) String() string {
    return fmt.Sprintf("%#v", *f)
}

// Value returns the slice of ints set by this flag
func (f *Int64Slice) Value() []int64 {
    return *f
}

// Get returns the slice of ints set by this flag
func (f *Int64Slice) Get() interface{} {
    return *f
}

// Apply populates the flag given the flag set and environment
// Ignores errors
func (f Int64SliceFlag) Apply(set *flag.FlagSet) {
    f.ApplyWithError(set)
}

// ApplyWithError populates the flag given the flag set and environment
func (f Int64SliceFlag) ApplyWithError(set *flag.FlagSet) error {
    if f.EnvVar != "" {
        for _, envVar := range strings.Split(f.EnvVar, ",") {
            envVar = strings.TrimSpace(envVar)
            if envVal, ok := syscall.Getenv(envVar); ok {
                newVal := &Int64Slice{}
                for _, s := range strings.Split(envVal, ",") {
                    s = strings.TrimSpace(s)
                    if err := newVal.Set(s); err != nil {
                        return fmt.Errorf("could not parse %s as int64 slice value for flag %s: %s", envVal, f.Name, err)
                    }
                }
                f.Value = newVal
                break
            }
        }
    }

    eachName(f.Name, func(name string) {
        if f.Value == nil {
            f.Value = &Int64Slice{}
        }
        set.Var(f.Value, name, f.Usage)
    })
    return nil
}

// Apply populates the flag given the flag set and environment
// Ignores errors
func (f BoolFlag) Apply(set *flag.FlagSet) {
    f.ApplyWithError(set)
}

// ApplyWithError populates the flag given the flag set and environment
func (f BoolFlag) ApplyWithError(set *flag.FlagSet) error {
    val := false
    if f.EnvVar != "" {
        for _, envVar := range strings.Split(f.EnvVar, ",") {
            envVar = strings.TrimSpace(envVar)
            if envVal, ok := syscall.Getenv(envVar); ok {
                if envVal == "" {
                    val = false
                    break
                }

                envValBool, err := strconv.ParseBool(envVal)
                if err != nil {
                    return fmt.Errorf("could not parse %s as bool value for flag %s: %s", envVal, f.Name, err)
                }

                val = envValBool
                break
            }
        }
    }

    eachName(f.Name, func(name string) {
        if f.Destination != nil {
            set.BoolVar(f.Destination, name, val, f.Usage)
            return
        }
        set.Bool(name, val, f.Usage)
    })

    return nil
}

// Apply populates the flag given the flag set and environment
// Ignores errors
func (f BoolTFlag) Apply(set *flag.FlagSet) {
    f.ApplyWithError(set)
}

// ApplyWithError populates the flag given the flag set and environment
func (f BoolTFlag) ApplyWithError(set *flag.FlagSet) error {
    val := true
    if f.EnvVar != "" {
        for _, envVar := range strings.Split(f.EnvVar, ",") {
            envVar = strings.TrimSpace(envVar)
            if envVal, ok := syscall.Getenv(envVar); ok {
                if envVal == "" {
                    val = false
                    break
                }

                envValBool, err := strconv.ParseBool(envVal)
                if err != nil {
                    return fmt.Errorf("could not parse %s as bool value for flag %s: %s", envVal, f.Name, err)
                }

                val = envValBool
                break
            }
        }
    }

    eachName(f.Name, func(name string) {
        if f.Destination != nil {
            set.BoolVar(f.Destination, name, val, f.Usage)
            return
        }
        set.Bool(name, val, f.Usage)
    })

    return nil
}

// Apply populates the flag given the flag set and environment
// Ignores errors
func (f StringFlag) Apply(set *flag.FlagSet) {
    f.ApplyWithError(set)
}

// ApplyWithError populates the flag given the flag set and environment
func (f StringFlag) ApplyWithError(set *flag.FlagSet) error {
    if f.EnvVar != "" {
        for _, envVar := range strings.Split(f.EnvVar, ",") {
            envVar = strings.TrimSpace(envVar)
            if envVal, ok := syscall.Getenv(envVar); ok {
                f.Value = envVal
                break
            }
        }
    }

    eachName(f.Name, func(name string) {
        if f.Destination != nil {
            set.StringVar(f.Destination, name, f.Value, f.Usage)
            return
        }
        set.String(name, f.Value, f.Usage)
    })

    return nil
}

// Apply populates the flag given the flag set and environment
// Ignores errors
func (f IntFlag) Apply(set *flag.FlagSet) {
    f.ApplyWithError(set)
}

// ApplyWithError populates the flag given the flag set and environment
func (f IntFlag) ApplyWithError(set *flag.FlagSet) error {
    if f.EnvVar != "" {
        for _, envVar := range strings.Split(f.EnvVar, ",") {
            envVar = strings.TrimSpace(envVar)
            if envVal, ok := syscall.Getenv(envVar); ok {
                envValInt, err := strconv.ParseInt(envVal, 0, 64)
                if err != nil {
                    return fmt.Errorf("could not parse %s as int value for flag %s: %s", envVal, f.Name, err)
                }
                f.Value = int(envValInt)
                break
            }
        }
    }

    eachName(f.Name, func(name string) {
        if f.Destination != nil {
            set.IntVar(f.Destination, name, f.Value, f.Usage)
            return
        }
        set.Int(name, f.Value, f.Usage)
    })

    return nil
}

// Apply populates the flag given the flag set and environment
// Ignores errors
func (f Int64Flag) Apply(set *flag.FlagSet) {
    f.ApplyWithError(set)
}

// ApplyWithError populates the flag given the flag set and environment
func (f Int64Flag) ApplyWithError(set *flag.FlagSet) error {
    if f.EnvVar != "" {
        for _, envVar := range strings.Split(f.EnvVar, ",") {
            envVar = strings.TrimSpace(envVar)
            if envVal, ok := syscall.Getenv(envVar); ok {
                envValInt, err := strconv.ParseInt(envVal, 0, 64)
                if err != nil {
                    return fmt.Errorf("could not parse %s as int value for flag %s: %s", envVal, f.Name, err)
                }

                f.Value = envValInt
                break
            }
        }
    }

    eachName(f.Name, func(name string) {
        if f.Destination != nil {
            set.Int64Var(f.Destination, name, f.Value, f.Usage)
            return
        }
        set.Int64(name, f.Value, f.Usage)
    })

    return nil
}

// Apply populates the flag given the flag set and environment
// Ignores errors
func (f UintFlag) Apply(set *flag.FlagSet) {
    f.ApplyWithError(set)
}

// ApplyWithError populates the flag given the flag set and environment
func (f UintFlag) ApplyWithError(set *flag.FlagSet) error {
    if f.EnvVar != "" {
        for _, envVar := range strings.Split(f.EnvVar, ",") {
            envVar = strings.TrimSpace(envVar)
            if envVal, ok := syscall.Getenv(envVar); ok {
                envValInt, err := strconv.ParseUint(envVal, 0, 64)
                if err != nil {
                    return fmt.Errorf("could not parse %s as uint value for flag %s: %s", envVal, f.Name, err)
                }

                f.Value = uint(envValInt)
                break
            }
        }
    }

    eachName(f.Name, func(name string) {
        if f.Destination != nil {
            set.UintVar(f.Destination, name, f.Value, f.Usage)
            return
        }
        set.Uint(name, f.Value, f.Usage)
    })

    return nil
}

// Apply populates the flag given the flag set and environment
// Ignores errors
func (f Uint64Flag) Apply(set *flag.FlagSet) {
    f.ApplyWithError(set)
}

// ApplyWithError populates the flag given the flag set and environment
func (f Uint64Flag) ApplyWithError(set *flag.FlagSet) error {
    if f.EnvVar != "" {
        for _, envVar := range strings.Split(f.EnvVar, ",") {
            envVar = strings.TrimSpace(envVar)
            if envVal, ok := syscall.Getenv(envVar); ok {
                envValInt, err := strconv.ParseUint(envVal, 0, 64)
                if err != nil {
                    return fmt.Errorf("could not parse %s as uint64 value for flag %s: %s", envVal, f.Name, err)
                }

                f.Value = uint64(envValInt)
                break
            }
        }
    }

    eachName(f.Name, func(name string) {
        if f.Destination != nil {
            set.Uint64Var(f.Destination, name, f.Value, f.Usage)
            return
        }
        set.Uint64(name, f.Value, f.Usage)
    })

    return nil
}

// Apply populates the flag given the flag set and environment
// Ignores errors
func (f DurationFlag) Apply(set *flag.FlagSet) {
    f.ApplyWithError(set)
}

// ApplyWithError populates the flag given the flag set and environment
func (f DurationFlag) ApplyWithError(set *flag.FlagSet) error {
    if f.EnvVar != "" {
        for _, envVar := range strings.Split(f.EnvVar, ",") {
            envVar = strings.TrimSpace(envVar)
            if envVal, ok := syscall.Getenv(envVar); ok {
                envValDuration, err := time.ParseDuration(envVal)
                if err != nil {
                    return fmt.Errorf("could not parse %s as duration for flag %s: %s", envVal, f.Name, err)
                }

                f.Value = envValDuration
                break
            }
        }
    }

    eachName(f.Name, func(name string) {
        if f.Destination != nil {
            set.DurationVar(f.Destination, name, f.Value, f.Usage)
            return
        }
        set.Duration(name, f.Value, f.Usage)
    })

    return nil
}

// Apply populates the flag given the flag set and environment
// Ignores errors
func (f Float64Flag) Apply(set *flag.FlagSet) {
    f.ApplyWithError(set)
}

// ApplyWithError populates the flag given the flag set and environment
func (f Float64Flag) ApplyWithError(set *flag.FlagSet) error {
    if f.EnvVar != "" {
        for _, envVar := range strings.Split(f.EnvVar, ",") {
            envVar = strings.TrimSpace(envVar)
            if envVal, ok := syscall.Getenv(envVar); ok {
                envValFloat, err := strconv.ParseFloat(envVal, 10)
                if err != nil {
                    return fmt.Errorf("could not parse %s as float64 value for flag %s: %s", envVal, f.Name, err)
                }

                f.Value = float64(envValFloat)
                break
            }
        }
    }

    eachName(f.Name, func(name string) {
        if f.Destination != nil {
            set.Float64Var(f.Destination, name, f.Value, f.Usage)
            return
        }
        set.Float64(name, f.Value, f.Usage)
    })

    return nil
}

func visibleFlags(fl []Flag) []Flag {
    visible := []Flag{}
    for _, flag := range fl {
        field := flagValue(flag).FieldByName("Hidden")
        if !field.IsValid() || !field.Bool() {
            visible = append(visible, flag)
        }
    }
    return visible
}

func prefixFor(name string) (prefix string) {
    if len(name) == 1 {
        prefix = "-"
    } else {
        prefix = "--"
    }

    return
}

// Returns the placeholder, if any, and the unquoted usage string.
func unquoteUsage(usage string) (string, string) {
    for i := 0; i < len(usage); i++ {
        if usage[i] == '`' {
            for j := i + 1; j < len(usage); j++ {
                if usage[j] == '`' {
                    name := usage[i+1 : j]
                    usage = usage[:i] + name + usage[j+1:]
                    return name, usage
                }
            }
            break
        }
    }
    return "", usage
}

func prefixedNames(fullName, placeholder string) string {
    var prefixed string
    parts := strings.Split(fullName, ",")
    for i, name := range parts {
        name = strings.Trim(name, " ")
        prefixed += prefixFor(name) + name
        if placeholder != "" {
            prefixed += " " + placeholder
        }
        if i < len(parts)-1 {
            prefixed += ", "
        }
    }
    return prefixed
}

func withEnvHint(envVar, str string) string {
    envText := ""
    if envVar != "" {
        prefix := "$"
        suffix := ""
        sep := ", $"
        if runtime.GOOS == "windows" {
            prefix = "%"
            suffix = "%"
            sep = "%, %"
        }
        envText = fmt.Sprintf(" [%s%s%s]", prefix, strings.Join(strings.Split(envVar, ","), sep), suffix)
    }
    return str + envText
}

func flagValue(f Flag) reflect.Value {
    fv := reflect.ValueOf(f)
    for fv.Kind() == reflect.Ptr {
        fv = reflect.Indirect(fv)
    }
    return fv
}

func stringifyFlag(f Flag) string {
    fv := flagValue(f)

    switch f.(type) {
    case IntSliceFlag:
        return withEnvHint(fv.FieldByName("EnvVar").String(),
            stringifyIntSliceFlag(f.(IntSliceFlag)))
    case Int64SliceFlag:
        return withEnvHint(fv.FieldByName("EnvVar").String(),
            stringifyInt64SliceFlag(f.(Int64SliceFlag)))
    case StringSliceFlag:
        return withEnvHint(fv.FieldByName("EnvVar").String(),
            stringifyStringSliceFlag(f.(StringSliceFlag)))
    }

    placeholder, usage := unquoteUsage(fv.FieldByName("Usage").String())

    needsPlaceholder := false
    defaultValueString := ""

    if val := fv.FieldByName("Value"); val.IsValid() {
        needsPlaceholder = true
        defaultValueString = fmt.Sprintf(" (default: %v)", val.Interface())

        if val.Kind() == reflect.String && val.String() != "" {
            defaultValueString = fmt.Sprintf(" (default: %q)", val.String())
        }
    }

    if defaultValueString == " (default: )" {
        defaultValueString = ""
    }

    if needsPlaceholder && placeholder == "" {
        placeholder = defaultPlaceholder
    }

    usageWithDefault := strings.TrimSpace(fmt.Sprintf("%s%s", usage, defaultValueString))

    return withEnvHint(fv.FieldByName("EnvVar").String(),
        fmt.Sprintf("%s\t%s", prefixedNames(fv.FieldByName("Name").String(), placeholder), usageWithDefault))
}

func stringifyIntSliceFlag(f IntSliceFlag) string {
    defaultVals := []string{}
    if f.Value != nil && len(f.Value.Value()) > 0 {
        for _, i := range f.Value.Value() {
            defaultVals = append(defaultVals, fmt.Sprintf("%d", i))
        }
    }

    return stringifySliceFlag(f.Usage, f.Name, defaultVals)
}

func stringifyInt64SliceFlag(f Int64SliceFlag) string {
    defaultVals := []string{}
    if f.Value != nil && len(f.Value.Value()) > 0 {
        for _, i := range f.Value.Value() {
            defaultVals = append(defaultVals, fmt.Sprintf("%d", i))
        }
    }

    return stringifySliceFlag(f.Usage, f.Name, defaultVals)
}

func stringifyStringSliceFlag(f StringSliceFlag) string {
    defaultVals := []string{}
    if f.Value != nil && len(f.Value.Value()) > 0 {
        for _, s := range f.Value.Value() {
            if len(s) > 0 {
                defaultVals = append(defaultVals, fmt.Sprintf("%q", s))
            }
        }
    }

    return stringifySliceFlag(f.Usage, f.Name, defaultVals)
}

func stringifySliceFlag(usage, name string, defaultVals []string) string {
    placeholder, usage := unquoteUsage(usage)
    if placeholder == "" {
        placeholder = defaultPlaceholder
    }

    defaultVal := ""
    if len(defaultVals) > 0 {
        defaultVal = fmt.Sprintf(" (default: %s)", strings.Join(defaultVals, ", "))
    }

    usageWithDefault := strings.TrimSpace(fmt.Sprintf("%s%s", usage, defaultVal))
    return fmt.Sprintf("%s\t%s", prefixedNames(name, placeholder), usageWithDefault)
}