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package cli
import (
"fmt"
"io"
"os"
"strings"
"text/tabwriter"
"text/template"
"unicode/utf8"
)
const (
helpName = "help"
helpAlias = "h"
)
// this instance is to avoid recursion in the ShowCommandHelp which can
// add a help command again
var helpCommandDontUse = &Command{
Name: helpName,
Aliases: []string{helpAlias},
Usage: "Shows a list of commands or help for one command",
ArgsUsage: "[command]",
}
var helpCommand = &Command{
Name: helpName,
Aliases: []string{helpAlias},
Usage: "Shows a list of commands or help for one command",
ArgsUsage: "[command]",
Action: func(cCtx *Context) error {
args := cCtx.Args()
argsPresent := args.First() != ""
firstArg := args.First()
// This action can be triggered by a "default" action of a command
// or via cmd.Run when cmd == helpCmd. So we have following possibilities
//
// 1 $ app
// 2 $ app help
// 3 $ app foo
// 4 $ app help foo
// 5 $ app foo help
// Case 4. when executing a help command set the context to parent
// to allow resolution of subsequent args. This will transform
// $ app help foo
// to
// $ app foo
// which will then be handled as case 3
if cCtx.Command.Name == helpName || cCtx.Command.Name == helpAlias {
cCtx = cCtx.parentContext
}
// Case 4. $ app hello foo
// foo is the command for which help needs to be shown
if argsPresent {
return ShowCommandHelp(cCtx, firstArg)
}
// Case 1 & 2
// Special case when running help on main app itself as opposed to individual
// commands/subcommands
if cCtx.parentContext.App == nil {
_ = ShowAppHelp(cCtx)
return nil
}
// Case 3, 5
if (len(cCtx.Command.Subcommands) == 1 && !cCtx.Command.HideHelp) ||
(len(cCtx.Command.Subcommands) == 0 && cCtx.Command.HideHelp) {
templ := cCtx.Command.CustomHelpTemplate
if templ == "" {
templ = CommandHelpTemplate
}
HelpPrinter(cCtx.App.Writer, templ, cCtx.Command)
return nil
}
return ShowSubcommandHelp(cCtx)
},
}
// Prints help for the App or Command
type helpPrinter func(w io.Writer, templ string, data interface{})
// Prints help for the App or Command with custom template function.
type helpPrinterCustom func(w io.Writer, templ string, data interface{}, customFunc map[string]interface{})
// HelpPrinter is a function that writes the help output. If not set explicitly,
// this calls HelpPrinterCustom using only the default template functions.
//
// If custom logic for printing help is required, this function can be
// overridden. If the ExtraInfo field is defined on an App, this function
// should not be modified, as HelpPrinterCustom will be used directly in order
// to capture the extra information.
var HelpPrinter helpPrinter = printHelp
// HelpPrinterCustom is a function that writes the help output. It is used as
// the default implementation of HelpPrinter, and may be called directly if
// the ExtraInfo field is set on an App.
//
// In the default implementation, if the customFuncs argument contains a
// "wrapAt" key, which is a function which takes no arguments and returns
// an int, this int value will be used to produce a "wrap" function used
// by the default template to wrap long lines.
var HelpPrinterCustom helpPrinterCustom = printHelpCustom
// VersionPrinter prints the version for the App
var VersionPrinter = printVersion
// ShowAppHelpAndExit - Prints the list of subcommands for the app and exits with exit code.
func ShowAppHelpAndExit(c *Context, exitCode int) {
_ = ShowAppHelp(c)
os.Exit(exitCode)
}
// ShowAppHelp is an action that displays the help.
func ShowAppHelp(cCtx *Context) error {
tpl := cCtx.App.CustomAppHelpTemplate
if tpl == "" {
tpl = AppHelpTemplate
}
if cCtx.App.ExtraInfo == nil {
HelpPrinter(cCtx.App.Writer, tpl, cCtx.App)
return nil
}
customAppData := func() map[string]interface{} {
return map[string]interface{}{
"ExtraInfo": cCtx.App.ExtraInfo,
}
}
HelpPrinterCustom(cCtx.App.Writer, tpl, cCtx.App, customAppData())
return nil
}
// DefaultAppComplete prints the list of subcommands as the default app completion method
func DefaultAppComplete(cCtx *Context) {
DefaultCompleteWithFlags(nil)(cCtx)
}
func printCommandSuggestions(commands []*Command, writer io.Writer) {
for _, command := range commands {
if command.Hidden {
continue
}
if strings.HasSuffix(os.Getenv("SHELL"), "zsh") {
for _, name := range command.Names() {
_, _ = fmt.Fprintf(writer, "%s:%s\n", name, command.Usage)
}
} else {
for _, name := range command.Names() {
_, _ = fmt.Fprintf(writer, "%s\n", name)
}
}
}
}
func cliArgContains(flagName string) bool {
for _, name := range strings.Split(flagName, ",") {
name = strings.TrimSpace(name)
count := utf8.RuneCountInString(name)
if count > 2 {
count = 2
}
flag := fmt.Sprintf("%s%s", strings.Repeat("-", count), name)
for _, a := range os.Args {
if a == flag {
return true
}
}
}
return false
}
func printFlagSuggestions(lastArg string, flags []Flag, writer io.Writer) {
cur := strings.TrimPrefix(lastArg, "-")
cur = strings.TrimPrefix(cur, "-")
for _, flag := range flags {
if bflag, ok := flag.(*BoolFlag); ok && bflag.Hidden {
continue
}
for _, name := range flag.Names() {
name = strings.TrimSpace(name)
// this will get total count utf8 letters in flag name
count := utf8.RuneCountInString(name)
if count > 2 {
count = 2 // reuse this count to generate single - or -- in flag completion
}
// if flag name has more than one utf8 letter and last argument in cli has -- prefix then
// skip flag completion for short flags example -v or -x
if strings.HasPrefix(lastArg, "--") && count == 1 {
continue
}
// match if last argument matches this flag and it is not repeated
if strings.HasPrefix(name, cur) && cur != name && !cliArgContains(name) {
flagCompletion := fmt.Sprintf("%s%s", strings.Repeat("-", count), name)
_, _ = fmt.Fprintln(writer, flagCompletion)
}
}
}
}
func DefaultCompleteWithFlags(cmd *Command) func(cCtx *Context) {
return func(cCtx *Context) {
if len(os.Args) > 2 {
lastArg := os.Args[len(os.Args)-2]
if strings.HasPrefix(lastArg, "-") {
if cmd != nil {
printFlagSuggestions(lastArg, cmd.Flags, cCtx.App.Writer)
return
}
printFlagSuggestions(lastArg, cCtx.App.Flags, cCtx.App.Writer)
return
}
}
if cmd != nil {
printCommandSuggestions(cmd.Subcommands, cCtx.App.Writer)
return
}
printCommandSuggestions(cCtx.App.Commands, cCtx.App.Writer)
}
}
// ShowCommandHelpAndExit - exits with code after showing help
func ShowCommandHelpAndExit(c *Context, command string, code int) {
_ = ShowCommandHelp(c, command)
os.Exit(code)
}
// ShowCommandHelp prints help for the given command
func ShowCommandHelp(ctx *Context, command string) error {
commands := ctx.App.Commands
if ctx.Command.Subcommands != nil {
commands = ctx.Command.Subcommands
}
for _, c := range commands {
if c.HasName(command) {
if !ctx.App.HideHelpCommand && !c.HasName(helpName) && len(c.Subcommands) != 0 && c.Command(helpName) == nil {
c.Subcommands = append(c.Subcommands, helpCommandDontUse)
}
if !ctx.App.HideHelp && HelpFlag != nil {
c.appendFlag(HelpFlag)
}
templ := c.CustomHelpTemplate
if templ == "" {
if len(c.Subcommands) == 0 {
templ = CommandHelpTemplate
} else {
templ = SubcommandHelpTemplate
}
}
HelpPrinter(ctx.App.Writer, templ, c)
return nil
}
}
if ctx.App.CommandNotFound == nil {
errMsg := fmt.Sprintf("No help topic for '%v'", command)
if ctx.App.Suggest {
if suggestion := SuggestCommand(ctx.Command.Subcommands, command); suggestion != "" {
errMsg += ". " + suggestion
}
}
return Exit(errMsg, 3)
}
ctx.App.CommandNotFound(ctx, command)
return nil
}
// ShowSubcommandHelpAndExit - Prints help for the given subcommand and exits with exit code.
func ShowSubcommandHelpAndExit(c *Context, exitCode int) {
_ = ShowSubcommandHelp(c)
os.Exit(exitCode)
}
// ShowSubcommandHelp prints help for the given subcommand
func ShowSubcommandHelp(cCtx *Context) error {
if cCtx == nil {
return nil
}
HelpPrinter(cCtx.App.Writer, SubcommandHelpTemplate, cCtx.Command)
return nil
}
// ShowVersion prints the version number of the App
func ShowVersion(cCtx *Context) {
VersionPrinter(cCtx)
}
func printVersion(cCtx *Context) {
_, _ = fmt.Fprintf(cCtx.App.Writer, "%v version %v\n", cCtx.App.Name, cCtx.App.Version)
}
// ShowCompletions prints the lists of commands within a given context
func ShowCompletions(cCtx *Context) {
a := cCtx.App
if a != nil && a.BashComplete != nil {
a.BashComplete(cCtx)
}
}
// ShowCommandCompletions prints the custom completions for a given command
func ShowCommandCompletions(ctx *Context, command string) {
c := ctx.App.Command(command)
if c != nil {
if c.BashComplete != nil {
c.BashComplete(ctx)
} else {
DefaultCompleteWithFlags(c)(ctx)
}
}
}
// printHelpCustom is the default implementation of HelpPrinterCustom.
//
// The customFuncs map will be combined with a default template.FuncMap to
// allow using arbitrary functions in template rendering.
func printHelpCustom(out io.Writer, templ string, data interface{}, customFuncs map[string]interface{}) {
const maxLineLength = 10000
funcMap := template.FuncMap{
"join": strings.Join,
"subtract": subtract,
"indent": indent,
"nindent": nindent,
"trim": strings.TrimSpace,
"wrap": func(input string, offset int) string { return wrap(input, offset, maxLineLength) },
"offset": offset,
"offsetCommands": offsetCommands,
}
if customFuncs["wrapAt"] != nil {
if wa, ok := customFuncs["wrapAt"]; ok {
if waf, ok := wa.(func() int); ok {
wrapAt := waf()
customFuncs["wrap"] = func(input string, offset int) string {
return wrap(input, offset, wrapAt)
}
}
}
}
for key, value := range customFuncs {
funcMap[key] = value
}
w := tabwriter.NewWriter(out, 1, 8, 2, ' ', 0)
t := template.Must(template.New("help").Funcs(funcMap).Parse(templ))
t.New("helpNameTemplate").Parse(helpNameTemplate)
t.New("usageTemplate").Parse(usageTemplate)
t.New("descriptionTemplate").Parse(descriptionTemplate)
t.New("visibleCommandTemplate").Parse(visibleCommandTemplate)
t.New("copyrightTemplate").Parse(copyrightTemplate)
t.New("versionTemplate").Parse(versionTemplate)
t.New("visibleFlagCategoryTemplate").Parse(visibleFlagCategoryTemplate)
t.New("visibleFlagTemplate").Parse(visibleFlagTemplate)
t.New("visibleGlobalFlagCategoryTemplate").Parse(strings.Replace(visibleFlagCategoryTemplate, "OPTIONS", "GLOBAL OPTIONS", -1))
t.New("authorsTemplate").Parse(authorsTemplate)
t.New("visibleCommandCategoryTemplate").Parse(visibleCommandCategoryTemplate)
err := t.Execute(w, data)
if err != nil {
// If the writer is closed, t.Execute will fail, and there's nothing
// we can do to recover.
if os.Getenv("CLI_TEMPLATE_ERROR_DEBUG") != "" {
_, _ = fmt.Fprintf(ErrWriter, "CLI TEMPLATE ERROR: %#v\n", err)
}
return
}
_ = w.Flush()
}
func printHelp(out io.Writer, templ string, data interface{}) {
HelpPrinterCustom(out, templ, data, nil)
}
func checkVersion(cCtx *Context) bool {
found := false
for _, name := range VersionFlag.Names() {
if cCtx.Bool(name) {
found = true
}
}
return found
}
func checkHelp(cCtx *Context) bool {
found := false
for _, name := range HelpFlag.Names() {
if cCtx.Bool(name) {
found = true
break
}
}
return found
}
func checkCommandHelp(c *Context, name string) bool {
if c.Bool("h") || c.Bool("help") {
_ = ShowCommandHelp(c, name)
return true
}
return false
}
func checkSubcommandHelp(cCtx *Context) bool {
if cCtx.Bool("h") || cCtx.Bool("help") {
_ = ShowSubcommandHelp(cCtx)
return true
}
return false
}
func checkShellCompleteFlag(a *App, arguments []string) (bool, []string) {
if !a.EnableBashCompletion {
return false, arguments
}
pos := len(arguments) - 1
lastArg := arguments[pos]
if lastArg != "--generate-bash-completion" {
return false, arguments
}
return true, arguments[:pos]
}
func checkCompletions(cCtx *Context) bool {
if !cCtx.shellComplete {
return false
}
if args := cCtx.Args(); args.Present() {
name := args.First()
if cmd := cCtx.App.Command(name); cmd != nil {
// let the command handle the completion
return false
}
}
ShowCompletions(cCtx)
return true
}
func checkCommandCompletions(c *Context, name string) bool {
if !c.shellComplete {
return false
}
ShowCommandCompletions(c, name)
return true
}
func subtract(a, b int) int {
return a - b
}
func indent(spaces int, v string) string {
pad := strings.Repeat(" ", spaces)
return pad + strings.Replace(v, "\n", "\n"+pad, -1)
}
func nindent(spaces int, v string) string {
return "\n" + indent(spaces, v)
}
func wrap(input string, offset int, wrapAt int) string {
var ss []string
lines := strings.Split(input, "\n")
padding := strings.Repeat(" ", offset)
for i, line := range lines {
if line == "" {
ss = append(ss, line)
} else {
wrapped := wrapLine(line, offset, wrapAt, padding)
if i == 0 {
ss = append(ss, wrapped)
} else {
ss = append(ss, padding+wrapped)
}
}
}
return strings.Join(ss, "\n")
}
func wrapLine(input string, offset int, wrapAt int, padding string) string {
if wrapAt <= offset || len(input) <= wrapAt-offset {
return input
}
lineWidth := wrapAt - offset
words := strings.Fields(input)
if len(words) == 0 {
return input
}
wrapped := words[0]
spaceLeft := lineWidth - len(wrapped)
for _, word := range words[1:] {
if len(word)+1 > spaceLeft {
wrapped += "\n" + padding + word
spaceLeft = lineWidth - len(word)
} else {
wrapped += " " + word
spaceLeft -= 1 + len(word)
}
}
return wrapped
}
func offset(input string, fixed int) int {
return len(input) + fixed
}
// this function tries to find the max width of the names column
// so say we have the following rows for help
//
// foo1, foo2, foo3 some string here
// bar1, b2 some other string here
//
// We want to offset the 2nd row usage by some amount so that everything
// is aligned
//
// foo1, foo2, foo3 some string here
// bar1, b2 some other string here
//
// to find that offset we find the length of all the rows and use the max
// to calculate the offset
func offsetCommands(cmds []*Command, fixed int) int {
var max int = 0
for _, cmd := range cmds {
s := strings.Join(cmd.Names(), ", ")
if len(s) > max {
max = len(s)
}
}
return max + fixed
}