main: switch to urfave/cli/v2

For now this is a drop in replacement for all the flags curently
implemented

Fixes: #171

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

vendor/github.com/urfave/cli/v2/command.go

@@ -0,0 +1,302 @@
+package cli
+
+import (
+	"flag"
+	"fmt"
+	"sort"
+	"strings"
+)
+
+// Command is a subcommand for a cli.App.
+type Command struct {
+	// The name of the command
+	Name string
+	// A list of aliases for the command
+	Aliases []string
+	// A short description of the usage of this command
+	Usage string
+	// Custom text to show on USAGE section of help
+	UsageText string
+	// A longer explanation of how the command works
+	Description string
+	// A short description of the arguments of this command
+	ArgsUsage string
+	// The category the command is part of
+	Category string
+	// The function to call when checking for bash command completions
+	BashComplete BashCompleteFunc
+	// An action to execute before any sub-subcommands are run, but after the context is ready
+	// If a non-nil error is returned, no sub-subcommands are run
+	Before BeforeFunc
+	// An action to execute after any subcommands are run, but after the subcommand has finished
+	// It is run even if Action() panics
+	After AfterFunc
+	// The function to call when this command is invoked
+	Action ActionFunc
+	// Execute this function if a usage error occurs.
+	OnUsageError OnUsageErrorFunc
+	// List of child commands
+	Subcommands []*Command
+	// List of flags to parse
+	Flags []Flag
+	// Treat all flags as normal arguments if true
+	SkipFlagParsing bool
+	// Boolean to hide built-in help command and help flag
+	HideHelp bool
+	// Boolean to hide built-in help command but keep help flag
+	// Ignored if HideHelp is true.
+	HideHelpCommand bool
+	// Boolean to hide this command from help or completion
+	Hidden bool
+	// Boolean to enable short-option handling so user can combine several
+	// single-character bool arguments into one
+	// i.e. foobar -o -v -> foobar -ov
+	UseShortOptionHandling bool
+
+	// Full name of command for help, defaults to full command name, including parent commands.
+	HelpName        string
+	commandNamePath []string
+
+	// CustomHelpTemplate the text template for the command help topic.
+	// cli.go uses text/template to render templates. You can
+	// render custom help text by setting this variable.
+	CustomHelpTemplate string
+}
+
+type Commands []*Command
+
+type CommandsByName []*Command
+
+func (c CommandsByName) Len() int {
+	return len(c)
+}
+
+func (c CommandsByName) Less(i, j int) bool {
+	return lexicographicLess(c[i].Name, c[j].Name)
+}
+
+func (c CommandsByName) Swap(i, j int) {
+	c[i], c[j] = c[j], c[i]
+}
+
+// FullName returns the full name of the command.
+// For subcommands this ensures that parent commands are part of the command path
+func (c *Command) FullName() string {
+	if c.commandNamePath == nil {
+		return c.Name
+	}
+	return strings.Join(c.commandNamePath, " ")
+}
+
+// Run invokes the command given the context, parses ctx.Args() to generate command-specific flags
+func (c *Command) Run(ctx *Context) (err error) {
+	if len(c.Subcommands) > 0 {
+		return c.startApp(ctx)
+	}
+
+	if !c.HideHelp && HelpFlag != nil {
+		// append help to flags
+		c.appendFlag(HelpFlag)
+	}
+
+	if ctx.App.UseShortOptionHandling {
+		c.UseShortOptionHandling = true
+	}
+
+	set, err := c.parseFlags(ctx.Args(), ctx.shellComplete)
+
+	context := NewContext(ctx.App, set, ctx)
+	context.Command = c
+	if checkCommandCompletions(context, c.Name) {
+		return nil
+	}
+
+	if err != nil {
+		if c.OnUsageError != nil {
+			err = c.OnUsageError(context, err, false)
+			context.App.handleExitCoder(context, err)
+			return err
+		}
+		_, _ = fmt.Fprintln(context.App.Writer, "Incorrect Usage:", err.Error())
+		_, _ = fmt.Fprintln(context.App.Writer)
+		_ = ShowCommandHelp(context, c.Name)
+		return err
+	}
+
+	if checkCommandHelp(context, c.Name) {
+		return nil
+	}
+
+	cerr := context.checkRequiredFlags(c.Flags)
+	if cerr != nil {
+		_ = ShowCommandHelp(context, c.Name)
+		return cerr
+	}
+
+	if c.After != nil {
+		defer func() {
+			afterErr := c.After(context)
+			if afterErr != nil {
+				context.App.handleExitCoder(context, err)
+				if err != nil {
+					err = newMultiError(err, afterErr)
+				} else {
+					err = afterErr
+				}
+			}
+		}()
+	}
+
+	if c.Before != nil {
+		err = c.Before(context)
+		if err != nil {
+			context.App.handleExitCoder(context, err)
+			return err
+		}
+	}
+
+	if c.Action == nil {
+		c.Action = helpSubcommand.Action
+	}
+
+	context.Command = c
+	err = c.Action(context)
+
+	if err != nil {
+		context.App.handleExitCoder(context, err)
+	}
+	return err
+}
+
+func (c *Command) newFlagSet() (*flag.FlagSet, error) {
+	return flagSet(c.Name, c.Flags)
+}
+
+func (c *Command) useShortOptionHandling() bool {
+	return c.UseShortOptionHandling
+}
+
+func (c *Command) parseFlags(args Args, shellComplete bool) (*flag.FlagSet, error) {
+	set, err := c.newFlagSet()
+	if err != nil {
+		return nil, err
+	}
+
+	if c.SkipFlagParsing {
+		return set, set.Parse(append([]string{"--"}, args.Tail()...))
+	}
+
+	err = parseIter(set, c, args.Tail(), shellComplete)
+	if err != nil {
+		return nil, err
+	}
+
+	err = normalizeFlags(c.Flags, set)
+	if err != nil {
+		return nil, err
+	}
+
+	return set, nil
+}
+
+// Names returns the names including short names and aliases.
+func (c *Command) Names() []string {
+	return append([]string{c.Name}, c.Aliases...)
+}
+
+// HasName returns true if Command.Name matches given name
+func (c *Command) HasName(name string) bool {
+	for _, n := range c.Names() {
+		if n == name {
+			return true
+		}
+	}
+	return false
+}
+
+func (c *Command) startApp(ctx *Context) error {
+	app := &App{
+		Metadata: ctx.App.Metadata,
+		Name:     fmt.Sprintf("%s %s", ctx.App.Name, c.Name),
+	}
+
+	if c.HelpName == "" {
+		app.HelpName = c.HelpName
+	} else {
+		app.HelpName = app.Name
+	}
+
+	app.Usage = c.Usage
+	app.UsageText = c.UsageText
+	app.Description = c.Description
+	app.ArgsUsage = c.ArgsUsage
+
+	// set CommandNotFound
+	app.CommandNotFound = ctx.App.CommandNotFound
+	app.CustomAppHelpTemplate = c.CustomHelpTemplate
+
+	// set the flags and commands
+	app.Commands = c.Subcommands
+	app.Flags = c.Flags
+	app.HideHelp = c.HideHelp
+	app.HideHelpCommand = c.HideHelpCommand
+
+	app.Version = ctx.App.Version
+	app.HideVersion = true
+	app.Compiled = ctx.App.Compiled
+	app.Reader = ctx.App.Reader
+	app.Writer = ctx.App.Writer
+	app.ErrWriter = ctx.App.ErrWriter
+	app.ExitErrHandler = ctx.App.ExitErrHandler
+	app.UseShortOptionHandling = ctx.App.UseShortOptionHandling
+
+	app.categories = newCommandCategories()
+	for _, command := range c.Subcommands {
+		app.categories.AddCommand(command.Category, command)
+	}
+
+	sort.Sort(app.categories.(*commandCategories))
+
+	// bash completion
+	app.EnableBashCompletion = ctx.App.EnableBashCompletion
+	if c.BashComplete != nil {
+		app.BashComplete = c.BashComplete
+	}
+
+	// set the actions
+	app.Before = c.Before
+	app.After = c.After
+	if c.Action != nil {
+		app.Action = c.Action
+	} else {
+		app.Action = helpSubcommand.Action
+	}
+	app.OnUsageError = c.OnUsageError
+
+	for index, cc := range app.Commands {
+		app.Commands[index].commandNamePath = []string{c.Name, cc.Name}
+	}
+
+	return app.RunAsSubcommand(ctx)
+}
+
+// VisibleFlags returns a slice of the Flags with Hidden=false
+func (c *Command) VisibleFlags() []Flag {
+	return visibleFlags(c.Flags)
+}
+
+func (c *Command) appendFlag(fl Flag) {
+	if !hasFlag(c.Flags, fl) {
+		c.Flags = append(c.Flags, fl)
+	}
+}
+
+func hasCommand(commands []*Command, command *Command) bool {
+	for _, existing := range commands {
+		if command == existing {
+			return true
+		}
+	}
+
+	return false
+}