Vendor temporarily

vendor/github.com/mitchellh/cli/cli.go

@@ -0,0 +1,741 @@
+package cli
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"regexp"
+	"sort"
+	"strings"
+	"sync"
+	"text/template"
+
+	"github.com/Masterminds/sprig"
+	"github.com/armon/go-radix"
+	"github.com/posener/complete"
+)
+
+// CLI contains the state necessary to run subcommands and parse the
+// command line arguments.
+//
+// CLI also supports nested subcommands, such as "cli foo bar". To use
+// nested subcommands, the key in the Commands mapping below contains the
+// full subcommand. In this example, it would be "foo bar".
+//
+// If you use a CLI with nested subcommands, some semantics change due to
+// ambiguities:
+//
+//   * We use longest prefix matching to find a matching subcommand. This
+//     means if you register "foo bar" and the user executes "cli foo qux",
+//     the "foo" command will be executed with the arg "qux". It is up to
+//     you to handle these args. One option is to just return the special
+//     help return code `RunResultHelp` to display help and exit.
+//
+//   * The help flag "-h" or "-help" will look at all args to determine
+//     the help function. For example: "otto apps list -h" will show the
+//     help for "apps list" but "otto apps -h" will show it for "apps".
+//     In the normal CLI, only the first subcommand is used.
+//
+//   * The help flag will list any subcommands that a command takes
+//     as well as the command's help itself. If there are no subcommands,
+//     it will note this. If the CLI itself has no subcommands, this entire
+//     section is omitted.
+//
+//   * Any parent commands that don't exist are automatically created as
+//     no-op commands that just show help for other subcommands. For example,
+//     if you only register "foo bar", then "foo" is automatically created.
+//
+type CLI struct {
+	// Args is the list of command-line arguments received excluding
+	// the name of the app. For example, if the command "./cli foo bar"
+	// was invoked, then Args should be []string{"foo", "bar"}.
+	Args []string
+
+	// Commands is a mapping of subcommand names to a factory function
+	// for creating that Command implementation. If there is a command
+	// with a blank string "", then it will be used as the default command
+	// if no subcommand is specified.
+	//
+	// If the key has a space in it, this will create a nested subcommand.
+	// For example, if the key is "foo bar", then to access it our CLI
+	// must be accessed with "./cli foo bar". See the docs for CLI for
+	// notes on how this changes some other behavior of the CLI as well.
+	//
+	// The factory should be as cheap as possible, ideally only allocating
+	// a struct. The factory may be called multiple times in the course
+	// of a command execution and certain events such as help require the
+	// instantiation of all commands. Expensive initialization should be
+	// deferred to function calls within the interface implementation.
+	Commands map[string]CommandFactory
+
+	// HiddenCommands is a list of commands that are "hidden". Hidden
+	// commands are not given to the help function callback and do not
+	// show up in autocomplete. The values in the slice should be equivalent
+	// to the keys in the command map.
+	HiddenCommands []string
+
+	// Name defines the name of the CLI.
+	Name string
+
+	// Version of the CLI.
+	Version string
+
+	// Autocomplete enables or disables subcommand auto-completion support.
+	// This is enabled by default when NewCLI is called. Otherwise, this
+	// must enabled explicitly.
+	//
+	// Autocomplete requires the "Name" option to be set on CLI. This name
+	// should be set exactly to the binary name that is autocompleted.
+	//
+	// Autocompletion is supported via the github.com/posener/complete
+	// library. This library supports bash, zsh and fish. To add support
+	// for other shells, please see that library.
+	//
+	// AutocompleteInstall and AutocompleteUninstall are the global flag
+	// names for installing and uninstalling the autocompletion handlers
+	// for the user's shell. The flag should omit the hyphen(s) in front of
+	// the value. Both single and double hyphens will automatically be supported
+	// for the flag name. These default to `autocomplete-install` and
+	// `autocomplete-uninstall` respectively.
+	//
+	// AutocompleteNoDefaultFlags is a boolean which controls if the default auto-
+	// complete flags like -help and -version are added to the output.
+	//
+	// AutocompleteGlobalFlags are a mapping of global flags for
+	// autocompletion. The help and version flags are automatically added.
+	Autocomplete               bool
+	AutocompleteInstall        string
+	AutocompleteUninstall      string
+	AutocompleteNoDefaultFlags bool
+	AutocompleteGlobalFlags    complete.Flags
+	autocompleteInstaller      autocompleteInstaller // For tests
+
+	// HelpFunc is the function called to generate the generic help
+	// text that is shown if help must be shown for the CLI that doesn't
+	// pertain to a specific command.
+	HelpFunc HelpFunc
+
+	// HelpWriter is used to print help text and version when requested.
+	// Defaults to os.Stderr for backwards compatibility.
+	// It is recommended that you set HelpWriter to os.Stdout, and
+	// ErrorWriter to os.Stderr.
+	HelpWriter io.Writer
+
+	// ErrorWriter used to output errors when a command can not be run.
+	// Defaults to the value of HelpWriter for backwards compatibility.
+	// It is recommended that you set HelpWriter to os.Stdout, and
+	// ErrorWriter to os.Stderr.
+	ErrorWriter io.Writer
+
+	//---------------------------------------------------------------
+	// Internal fields set automatically
+
+	once           sync.Once
+	autocomplete   *complete.Complete
+	commandTree    *radix.Tree
+	commandNested  bool
+	commandHidden  map[string]struct{}
+	subcommand     string
+	subcommandArgs []string
+	topFlags       []string
+
+	// These are true when special global flags are set. We can/should
+	// probably use a bitset for this one day.
+	isHelp                  bool
+	isVersion               bool
+	isAutocompleteInstall   bool
+	isAutocompleteUninstall bool
+}
+
+// NewClI returns a new CLI instance with sensible defaults.
+func NewCLI(app, version string) *CLI {
+	return &CLI{
+		Name:         app,
+		Version:      version,
+		HelpFunc:     BasicHelpFunc(app),
+		Autocomplete: true,
+	}
+
+}
+
+// IsHelp returns whether or not the help flag is present within the
+// arguments.
+func (c *CLI) IsHelp() bool {
+	c.once.Do(c.init)
+	return c.isHelp
+}
+
+// IsVersion returns whether or not the version flag is present within the
+// arguments.
+func (c *CLI) IsVersion() bool {
+	c.once.Do(c.init)
+	return c.isVersion
+}
+
+// Run runs the actual CLI based on the arguments given.
+func (c *CLI) Run() (int, error) {
+	c.once.Do(c.init)
+
+	// If this is a autocompletion request, satisfy it. This must be called
+	// first before anything else since its possible to be autocompleting
+	// -help or -version or other flags and we want to show completions
+	// and not actually write the help or version.
+	if c.Autocomplete && c.autocomplete.Complete() {
+		return 0, nil
+	}
+
+	// Just show the version and exit if instructed.
+	if c.IsVersion() && c.Version != "" {
+		c.HelpWriter.Write([]byte(c.Version + "\n"))
+		return 0, nil
+	}
+
+	// Just print the help when only '-h' or '--help' is passed.
+	if c.IsHelp() && c.Subcommand() == "" {
+		c.HelpWriter.Write([]byte(c.HelpFunc(c.helpCommands(c.Subcommand())) + "\n"))
+		return 0, nil
+	}
+
+	// If we're attempting to install or uninstall autocomplete then handle
+	if c.Autocomplete {
+		// Autocomplete requires the "Name" to be set so that we know what
+		// command to setup the autocomplete on.
+		if c.Name == "" {
+			return 1, fmt.Errorf(
+				"internal error: CLI.Name must be specified for autocomplete to work")
+		}
+
+		// If both install and uninstall flags are specified, then error
+		if c.isAutocompleteInstall && c.isAutocompleteUninstall {
+			return 1, fmt.Errorf(
+				"Either the autocomplete install or uninstall flag may " +
+					"be specified, but not both.")
+		}
+
+		// If the install flag is specified, perform the install or uninstall
+		if c.isAutocompleteInstall {
+			if err := c.autocompleteInstaller.Install(c.Name); err != nil {
+				return 1, err
+			}
+
+			return 0, nil
+		}
+
+		if c.isAutocompleteUninstall {
+			if err := c.autocompleteInstaller.Uninstall(c.Name); err != nil {
+				return 1, err
+			}
+
+			return 0, nil
+		}
+	}
+
+	// Attempt to get the factory function for creating the command
+	// implementation. If the command is invalid or blank, it is an error.
+	raw, ok := c.commandTree.Get(c.Subcommand())
+	if !ok {
+		c.ErrorWriter.Write([]byte(c.HelpFunc(c.helpCommands(c.subcommandParent())) + "\n"))
+		return 127, nil
+	}
+
+	command, err := raw.(CommandFactory)()
+	if err != nil {
+		return 1, err
+	}
+
+	// If we've been instructed to just print the help, then print it
+	if c.IsHelp() {
+		c.commandHelp(c.HelpWriter, command)
+		return 0, nil
+	}
+
+	// If there is an invalid flag, then error
+	if len(c.topFlags) > 0 {
+		c.ErrorWriter.Write([]byte(
+			"Invalid flags before the subcommand. If these flags are for\n" +
+				"the subcommand, please put them after the subcommand.\n\n"))
+		c.commandHelp(c.ErrorWriter, command)
+		return 1, nil
+	}
+
+	code := command.Run(c.SubcommandArgs())
+	if code == RunResultHelp {
+		// Requesting help
+		c.commandHelp(c.ErrorWriter, command)
+		return 1, nil
+	}
+
+	return code, nil
+}
+
+// Subcommand returns the subcommand that the CLI would execute. For
+// example, a CLI from "--version version --help" would return a Subcommand
+// of "version"
+func (c *CLI) Subcommand() string {
+	c.once.Do(c.init)
+	return c.subcommand
+}
+
+// SubcommandArgs returns the arguments that will be passed to the
+// subcommand.
+func (c *CLI) SubcommandArgs() []string {
+	c.once.Do(c.init)
+	return c.subcommandArgs
+}
+
+// subcommandParent returns the parent of this subcommand, if there is one.
+// If there isn't on, "" is returned.
+func (c *CLI) subcommandParent() string {
+	// Get the subcommand, if it is "" alread just return
+	sub := c.Subcommand()
+	if sub == "" {
+		return sub
+	}
+
+	// Clear any trailing spaces and find the last space
+	sub = strings.TrimRight(sub, " ")
+	idx := strings.LastIndex(sub, " ")
+
+	if idx == -1 {
+		// No space means our parent is root
+		return ""
+	}
+
+	return sub[:idx]
+}
+
+func (c *CLI) init() {
+	if c.HelpFunc == nil {
+		c.HelpFunc = BasicHelpFunc("app")
+
+		if c.Name != "" {
+			c.HelpFunc = BasicHelpFunc(c.Name)
+		}
+	}
+
+	if c.HelpWriter == nil {
+		c.HelpWriter = os.Stderr
+	}
+	if c.ErrorWriter == nil {
+		c.ErrorWriter = c.HelpWriter
+	}
+
+	// Build our hidden commands
+	if len(c.HiddenCommands) > 0 {
+		c.commandHidden = make(map[string]struct{})
+		for _, h := range c.HiddenCommands {
+			c.commandHidden[h] = struct{}{}
+		}
+	}
+
+	// Build our command tree
+	c.commandTree = radix.New()
+	c.commandNested = false
+	for k, v := range c.Commands {
+		k = strings.TrimSpace(k)
+		c.commandTree.Insert(k, v)
+		if strings.ContainsRune(k, ' ') {
+			c.commandNested = true
+		}
+	}
+
+	// Go through the key and fill in any missing parent commands
+	if c.commandNested {
+		var walkFn radix.WalkFn
+		toInsert := make(map[string]struct{})
+		walkFn = func(k string, raw interface{}) bool {
+			idx := strings.LastIndex(k, " ")
+			if idx == -1 {
+				// If there is no space, just ignore top level commands
+				return false
+			}
+
+			// Trim up to that space so we can get the expected parent
+			k = k[:idx]
+			if _, ok := c.commandTree.Get(k); ok {
+				// Yay we have the parent!
+				return false
+			}
+
+			// We're missing the parent, so let's insert this
+			toInsert[k] = struct{}{}
+
+			// Call the walk function recursively so we check this one too
+			return walkFn(k, nil)
+		}
+
+		// Walk!
+		c.commandTree.Walk(walkFn)
+
+		// Insert any that we're missing
+		for k := range toInsert {
+			var f CommandFactory = func() (Command, error) {
+				return &MockCommand{
+					HelpText:  "This command is accessed by using one of the subcommands below.",
+					RunResult: RunResultHelp,
+				}, nil
+			}
+
+			c.commandTree.Insert(k, f)
+		}
+	}
+
+	// Setup autocomplete if we have it enabled. We have to do this after
+	// the command tree is setup so we can use the radix tree to easily find
+	// all subcommands.
+	if c.Autocomplete {
+		c.initAutocomplete()
+	}
+
+	// Process the args
+	c.processArgs()
+}
+
+func (c *CLI) initAutocomplete() {
+	if c.AutocompleteInstall == "" {
+		c.AutocompleteInstall = defaultAutocompleteInstall
+	}
+
+	if c.AutocompleteUninstall == "" {
+		c.AutocompleteUninstall = defaultAutocompleteUninstall
+	}
+
+	if c.autocompleteInstaller == nil {
+		c.autocompleteInstaller = &realAutocompleteInstaller{}
+	}
+
+	// We first set c.autocomplete to a noop autocompleter that outputs
+	// to nul so that we can detect if we're autocompleting or not. If we're
+	// not, then we do nothing. This saves a LOT of compute cycles since
+	// initAutoCompleteSub has to walk every command.
+	c.autocomplete = complete.New(c.Name, complete.Command{})
+	c.autocomplete.Out = ioutil.Discard
+	if !c.autocomplete.Complete() {
+		return
+	}
+
+	// Build the root command
+	cmd := c.initAutocompleteSub("")
+
+	// For the root, we add the global flags to the "Flags". This way
+	// they don't show up on every command.
+	if !c.AutocompleteNoDefaultFlags {
+		cmd.Flags = map[string]complete.Predictor{
+			"-" + c.AutocompleteInstall:   complete.PredictNothing,
+			"-" + c.AutocompleteUninstall: complete.PredictNothing,
+			"-help":                       complete.PredictNothing,
+			"-version":                    complete.PredictNothing,
+		}
+	}
+	cmd.GlobalFlags = c.AutocompleteGlobalFlags
+
+	c.autocomplete = complete.New(c.Name, cmd)
+}
+
+// initAutocompleteSub creates the complete.Command for a subcommand with
+// the given prefix. This will continue recursively for all subcommands.
+// The prefix "" (empty string) can be used for the root command.
+func (c *CLI) initAutocompleteSub(prefix string) complete.Command {
+	var cmd complete.Command
+	walkFn := func(k string, raw interface{}) bool {
+		// Ignore the empty key which can be present for default commands.
+		if k == "" {
+			return false
+		}
+
+		// Keep track of the full key so that we can nest further if necessary
+		fullKey := k
+
+		if len(prefix) > 0 {
+			// If we have a prefix, trim the prefix + 1 (for the space)
+			// Example: turns "sub one" to "one" with prefix "sub"
+			k = k[len(prefix)+1:]
+		}
+
+		if idx := strings.Index(k, " "); idx >= 0 {
+			// If there is a space, we trim up to the space. This turns
+			// "sub sub2 sub3" into "sub". The prefix trim above will
+			// trim our current depth properly.
+			k = k[:idx]
+		}
+
+		if _, ok := cmd.Sub[k]; ok {
+			// If we already tracked this subcommand then ignore
+			return false
+		}
+
+		// If the command is hidden, don't record it at all
+		if _, ok := c.commandHidden[fullKey]; ok {
+			return false
+		}
+
+		if cmd.Sub == nil {
+			cmd.Sub = complete.Commands(make(map[string]complete.Command))
+		}
+		subCmd := c.initAutocompleteSub(fullKey)
+
+		// Instantiate the command so that we can check if the command is
+		// a CommandAutocomplete implementation. If there is an error
+		// creating the command, we just ignore it since that will be caught
+		// later.
+		impl, err := raw.(CommandFactory)()
+		if err != nil {
+			impl = nil
+		}
+
+		// Check if it implements ComandAutocomplete. If so, setup the autocomplete
+		if c, ok := impl.(CommandAutocomplete); ok {
+			subCmd.Args = c.AutocompleteArgs()
+			subCmd.Flags = c.AutocompleteFlags()
+		}
+
+		cmd.Sub[k] = subCmd
+		return false
+	}
+
+	walkPrefix := prefix
+	if walkPrefix != "" {
+		walkPrefix += " "
+	}
+
+	c.commandTree.WalkPrefix(walkPrefix, walkFn)
+	return cmd
+}
+
+func (c *CLI) commandHelp(out io.Writer, command Command) {
+	// Get the template to use
+	tpl := strings.TrimSpace(defaultHelpTemplate)
+	if t, ok := command.(CommandHelpTemplate); ok {
+		tpl = t.HelpTemplate()
+	}
+	if !strings.HasSuffix(tpl, "\n") {
+		tpl += "\n"
+	}
+
+	// Parse it
+	t, err := template.New("root").Funcs(sprig.TxtFuncMap()).Parse(tpl)
+	if err != nil {
+		t = template.Must(template.New("root").Parse(fmt.Sprintf(
+			"Internal error! Failed to parse command help template: %s\n", err)))
+	}
+
+	// Template data
+	data := map[string]interface{}{
+		"Name":           c.Name,
+		"SubcommandName": c.Subcommand(),
+		"Help":           command.Help(),
+	}
+
+	// Build subcommand list if we have it
+	var subcommandsTpl []map[string]interface{}
+	if c.commandNested {
+		// Get the matching keys
+		subcommands := c.helpCommands(c.Subcommand())
+		keys := make([]string, 0, len(subcommands))
+		for k := range subcommands {
+			keys = append(keys, k)
+		}
+
+		// Sort the keys
+		sort.Strings(keys)
+
+		// Figure out the padding length
+		var longest int
+		for _, k := range keys {
+			if v := len(k); v > longest {
+				longest = v
+			}
+		}
+
+		// Go through and create their structures
+		subcommandsTpl = make([]map[string]interface{}, 0, len(subcommands))
+		for _, k := range keys {
+			// Get the command
+			raw, ok := subcommands[k]
+			if !ok {
+				c.ErrorWriter.Write([]byte(fmt.Sprintf(
+					"Error getting subcommand %q", k)))
+			}
+			sub, err := raw()
+			if err != nil {
+				c.ErrorWriter.Write([]byte(fmt.Sprintf(
+					"Error instantiating %q: %s", k, err)))
+			}
+
+			// Find the last space and make sure we only include that last part
+			name := k
+			if idx := strings.LastIndex(k, " "); idx > -1 {
+				name = name[idx+1:]
+			}
+
+			subcommandsTpl = append(subcommandsTpl, map[string]interface{}{
+				"Name":        name,
+				"NameAligned": name + strings.Repeat(" ", longest-len(k)),
+				"Help":        sub.Help(),
+				"Synopsis":    sub.Synopsis(),
+			})
+		}
+	}
+	data["Subcommands"] = subcommandsTpl
+
+	// Write
+	err = t.Execute(out, data)
+	if err == nil {
+		return
+	}
+
+	// An error, just output...
+	c.ErrorWriter.Write([]byte(fmt.Sprintf(
+		"Internal error rendering help: %s", err)))
+}
+
+// helpCommands returns the subcommands for the HelpFunc argument.
+// This will only contain immediate subcommands.
+func (c *CLI) helpCommands(prefix string) map[string]CommandFactory {
+	// If our prefix isn't empty, make sure it ends in ' '
+	if prefix != "" && prefix[len(prefix)-1] != ' ' {
+		prefix += " "
+	}
+
+	// Get all the subkeys of this command
+	var keys []string
+	c.commandTree.WalkPrefix(prefix, func(k string, raw interface{}) bool {
+		// Ignore any sub-sub keys, i.e. "foo bar baz" when we want "foo bar"
+		if !strings.Contains(k[len(prefix):], " ") {
+			keys = append(keys, k)
+		}
+
+		return false
+	})
+
+	// For each of the keys return that in the map
+	result := make(map[string]CommandFactory, len(keys))
+	for _, k := range keys {
+		raw, ok := c.commandTree.Get(k)
+		if !ok {
+			// We just got it via WalkPrefix above, so we just panic
+			panic("not found: " + k)
+		}
+
+		// If this is a hidden command, don't show it
+		if _, ok := c.commandHidden[k]; ok {
+			continue
+		}
+
+		result[k] = raw.(CommandFactory)
+	}
+
+	return result
+}
+
+func (c *CLI) processArgs() {
+	for i, arg := range c.Args {
+		if arg == "--" {
+			break
+		}
+
+		// Check for help flags.
+		if arg == "-h" || arg == "-help" || arg == "--help" {
+			c.isHelp = true
+			continue
+		}
+
+		// Check for autocomplete flags
+		if c.Autocomplete {
+			if arg == "-"+c.AutocompleteInstall || arg == "--"+c.AutocompleteInstall {
+				c.isAutocompleteInstall = true
+				continue
+			}
+
+			if arg == "-"+c.AutocompleteUninstall || arg == "--"+c.AutocompleteUninstall {
+				c.isAutocompleteUninstall = true
+				continue
+			}
+		}
+
+		if c.subcommand == "" {
+			// Check for version flags if not in a subcommand.
+			if arg == "-v" || arg == "-version" || arg == "--version" {
+				c.isVersion = true
+				continue
+			}
+
+			if arg != "" && arg[0] == '-' {
+				// Record the arg...
+				c.topFlags = append(c.topFlags, arg)
+			}
+		}
+
+		// If we didn't find a subcommand yet and this is the first non-flag
+		// argument, then this is our subcommand.
+		if c.subcommand == "" && arg != "" && arg[0] != '-' {
+			c.subcommand = arg
+			if c.commandNested {
+				// If the command has a space in it, then it is invalid.
+				// Set a blank command so that it fails.
+				if strings.ContainsRune(arg, ' ') {
+					c.subcommand = ""
+					return
+				}
+
+				// Determine the argument we look to to end subcommands.
+				// We look at all arguments until one has a space. This
+				// disallows commands like: ./cli foo "bar baz". An argument
+				// with a space is always an argument.
+				j := 0
+				for k, v := range c.Args[i:] {
+					if strings.ContainsRune(v, ' ') {
+						break
+					}
+
+					j = i + k + 1
+				}
+
+				// Nested CLI, the subcommand is actually the entire
+				// arg list up to a flag that is still a valid subcommand.
+				searchKey := strings.Join(c.Args[i:j], " ")
+				k, _, ok := c.commandTree.LongestPrefix(searchKey)
+				if ok {
+					// k could be a prefix that doesn't contain the full
+					// command such as "foo" instead of "foobar", so we
+					// need to verify that we have an entire key. To do that,
+					// we look for an ending in a space or an end of string.
+					reVerify := regexp.MustCompile(regexp.QuoteMeta(k) + `( |$)`)
+					if reVerify.MatchString(searchKey) {
+						c.subcommand = k
+						i += strings.Count(k, " ")
+					}
+				}
+			}
+
+			// The remaining args the subcommand arguments
+			c.subcommandArgs = c.Args[i+1:]
+		}
+	}
+
+	// If we never found a subcommand and support a default command, then
+	// switch to using that.
+	if c.subcommand == "" {
+		if _, ok := c.Commands[""]; ok {
+			args := c.topFlags
+			args = append(args, c.subcommandArgs...)
+			c.topFlags = nil
+			c.subcommandArgs = args
+		}
+	}
+}
+
+// defaultAutocompleteInstall and defaultAutocompleteUninstall are the
+// default values for the autocomplete install and uninstall flags.
+const defaultAutocompleteInstall = "autocomplete-install"
+const defaultAutocompleteUninstall = "autocomplete-uninstall"
+
+const defaultHelpTemplate = `
+{{.Help}}{{if gt (len .Subcommands) 0}}
+
+Subcommands:
+{{- range $value := .Subcommands }}
+    {{ $value.NameAligned }}    {{ $value.Synopsis }}{{ end }}
+{{- end }}
+`