vendor: add in external packages for use with CLI

crypto/ssh/terminal gets us information about the terminal, such as
its dimensions and state. It also allows us to manipulate the terminal.
For example, we can put the terminal in raw mode when a passphrase needs
to be entered.

This commit also add the github.com/urfave/cli package which we will use
to write the command line tool component of fscrypt. This tool allows
for us to easily use commands and subcommands.

Note that this is actually the upstream repository with two PRs applied:

https://github.com/urfave/cli/pull/629
https://github.com/urfave/cli/pull/630

They fix bugs in the handling of custom usage errors.

Change-Id: I2d3ba967b1bce8f73440e3a06df4eaba7ab96c19

1 files changed, 300 insertions, 0 deletions

diff --git a/vendor/github.com/urfave/cli/command.go b/vendor/github.com/urfave/cli/command.go
new file mode 100644
index 0000000..84946e7
--- /dev/null
+++ b/vendor/github.com/urfave/cli/command.go
@@ -0,0 +1,300 @@
+package cli
+
+import (
+	"fmt"
+	"io/ioutil"
+	"sort"
+	"strings"
+)
+
+// Command is a subcommand for a cli.App.
+type Command struct {
+	// The name of the command
+	Name string
+	// short name of the command. Typically one character (deprecated, use `Aliases`)
+	ShortName 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 interface{}
+	// TODO: replace `Action: interface{}` with `Action: ActionFunc` once some kind
+	// of deprecation period has passed, maybe?
+
+	// Execute this function if a usage error occurs.
+	OnUsageError OnUsageErrorFunc
+	// List of child commands
+	Subcommands Commands
+	// List of flags to parse
+	Flags []Flag
+	// Treat all flags as normal arguments if true
+	SkipFlagParsing bool
+	// Skip argument reordering which attempts to move flags before arguments,
+	// but only works if all flags appear after all arguments. This behavior was
+	// removed n version 2 since it only works under specific conditions so we
+	// backport here by exposing it as an option for compatibility.
+	SkipArgReorder bool
+	// Boolean to hide built-in help command
+	HideHelp bool
+	// Boolean to hide this command from help or completion
+	Hidden bool
+
+	// Full name of command for help, defaults to full command name, including parent commands.
+	HelpName        string
+	commandNamePath []string
+}
+
+type CommandsByName []Command
+
+func (c CommandsByName) Len() int {
+	return len(c)
+}
+
+func (c CommandsByName) Less(i, j int) bool {
+	return 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, " ")
+}
+
+// Commands is a slice of Command
+type Commands []Command
+
+// 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 != BoolFlag{}) {
+		// append help to flags
+		c.Flags = append(
+			c.Flags,
+			HelpFlag,
+		)
+	}
+
+	set, err := flagSet(c.Name, c.Flags)
+	if err != nil {
+		return err
+	}
+	set.SetOutput(ioutil.Discard)
+
+	if c.SkipFlagParsing {
+		err = set.Parse(append([]string{"--"}, ctx.Args().Tail()...))
+	} else if !c.SkipArgReorder {
+		firstFlagIndex := -1
+		terminatorIndex := -1
+		for index, arg := range ctx.Args() {
+			if arg == "--" {
+				terminatorIndex = index
+				break
+			} else if arg == "-" {
+				// Do nothing. A dash alone is not really a flag.
+				continue
+			} else if strings.HasPrefix(arg, "-") && firstFlagIndex == -1 {
+				firstFlagIndex = index
+			}
+		}
+
+		if firstFlagIndex > -1 {
+			args := ctx.Args()
+			regularArgs := make([]string, len(args[1:firstFlagIndex]))
+			copy(regularArgs, args[1:firstFlagIndex])
+
+			var flagArgs []string
+			if terminatorIndex > -1 {
+				flagArgs = args[firstFlagIndex:terminatorIndex]
+				regularArgs = append(regularArgs, args[terminatorIndex:]...)
+			} else {
+				flagArgs = args[firstFlagIndex:]
+			}
+
+			err = set.Parse(append(flagArgs, regularArgs...))
+		} else {
+			err = set.Parse(ctx.Args().Tail())
+		}
+	} else {
+		err = set.Parse(ctx.Args().Tail())
+	}
+
+	nerr := normalizeFlags(c.Flags, set)
+	if nerr != nil {
+		fmt.Fprintln(ctx.App.Writer, nerr)
+		fmt.Fprintln(ctx.App.Writer)
+		ShowCommandHelp(ctx, c.Name)
+		return nerr
+	}
+
+	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)
+			HandleExitCoder(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
+	}
+
+	if c.After != nil {
+		defer func() {
+			afterErr := c.After(context)
+			if afterErr != nil {
+				HandleExitCoder(err)
+				if err != nil {
+					err = NewMultiError(err, afterErr)
+				} else {
+					err = afterErr
+				}
+			}
+		}()
+	}
+
+	if c.Before != nil {
+		err = c.Before(context)
+		if err != nil {
+			fmt.Fprintln(context.App.Writer, err)
+			fmt.Fprintln(context.App.Writer)
+			ShowCommandHelp(context, c.Name)
+			HandleExitCoder(err)
+			return err
+		}
+	}
+
+	if c.Action == nil {
+		c.Action = helpSubcommand.Action
+	}
+
+	err = HandleAction(c.Action, context)
+
+	if err != nil {
+		HandleExitCoder(err)
+	}
+	return err
+}
+
+// Names returns the names including short names and aliases.
+func (c Command) Names() []string {
+	names := []string{c.Name}
+
+	if c.ShortName != "" {
+		names = append(names, c.ShortName)
+	}
+
+	return append(names, c.Aliases...)
+}
+
+// HasName returns true if Command.Name or Command.ShortName 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 := NewApp()
+	app.Metadata = ctx.App.Metadata
+	// set the name and usage
+	app.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.Description = c.Description
+	app.ArgsUsage = c.ArgsUsage
+
+	// set CommandNotFound
+	app.CommandNotFound = ctx.App.CommandNotFound
+
+	// set the flags and commands
+	app.Commands = c.Subcommands
+	app.Flags = c.Flags
+	app.HideHelp = c.HideHelp
+
+	app.Version = ctx.App.Version
+	app.HideVersion = ctx.App.HideVersion
+	app.Compiled = ctx.App.Compiled
+	app.Author = ctx.App.Author
+	app.Email = ctx.App.Email
+	app.Writer = ctx.App.Writer
+	app.ErrWriter = ctx.App.ErrWriter
+
+	app.categories = CommandCategories{}
+	for _, command := range c.Subcommands {
+		app.categories = app.categories.AddCommand(command.Category, command)
+	}
+
+	sort.Sort(app.categories)
+
+	// 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)
+}