Switch to dep for dependency management

vendor/github.com/jessevdk/go-flags/parser.go

@@ -5,8 +5,13 @@
 package flags
 
 import (
+	"bytes"
+	"fmt"
 	"os"
 	"path"
+	"sort"
+	"strings"
+	"unicode/utf8"
 )
 
 // A Parser provides command line option parsing. It can contain several
@@ -32,6 +37,21 @@ type Parser struct {
 	// or an error to indicate a parse failure.
 	UnknownOptionHandler func(option string, arg SplitArgument, args []string) ([]string, error)
 
+	// CompletionHandler is a function gets called to handle the completion of
+	// items. By default, the items are printed and the application is exited.
+	// You can override this default behavior by specifying a custom CompletionHandler.
+	CompletionHandler func(items []Completion)
+
+	// CommandHandler is a function that gets called to handle execution of a
+	// command. By default, the command will simply be executed. This can be
+	// overridden to perform certain actions (such as applying global flags)
+	// just before the command is executed. Note that if you override the
+	// handler it is your responsibility to call the command.Execute function.
+	//
+	// The command passed into CommandHandler may be nil in case there is no
+	// command to be executed when parsing has finished.
+	CommandHandler func(command Commander, args []string) error
+
 	internalError error
 }
 
@@ -67,7 +87,7 @@ const (
 	// -h and --help options. When either -h or --help is specified on the
 	// command line, the parser will return the special error of type
 	// ErrHelp. When PrintErrors is also specified, then the help message
-	// will also be automatically printed to os.Stderr.
+	// will also be automatically printed to os.Stdout.
 	HelpFlag = 1 << iota
 
 	// PassDoubleDash passes all arguments after a double dash, --, as
@@ -80,7 +100,8 @@ const (
 	IgnoreUnknown
 
 	// PrintErrors prints any errors which occurred during parsing to
-	// os.Stderr.
+	// os.Stderr. In the special case of ErrHelp, the message will be printed
+	// to os.Stdout.
 	PrintErrors
 
 	// PassAfterNonOption passes all arguments after the first non option
@@ -93,6 +114,17 @@ const (
 	Default = HelpFlag | PrintErrors | PassDoubleDash
 )
 
+type parseState struct {
+	arg        string
+	args       []string
+	retargs    []string
+	positional []*Arg
+	err        error
+
+	command *Command
+	lookup  lookup
+}
+
 // Parse is a convenience function to parse command line options with default
 // settings. The provided data is a pointer to a struct representing the
 // default option group (named "Application Options"). For more control, use
@@ -162,14 +194,19 @@ func (p *Parser) Parse() ([]string, error) {
 //
 // When the common help group has been added (AddHelp) and either -h or --help
 // was specified in the command line arguments, a help message will be
-// automatically printed. Furthermore, the special error type ErrHelp is returned.
+// automatically printed if the PrintErrors option is enabled.
+// Furthermore, the special error type ErrHelp is returned.
 // It is up to the caller to exit the program if so desired.
 func (p *Parser) ParseArgs(args []string) ([]string, error) {
 	if p.internalError != nil {
 		return nil, p.internalError
 	}
 
-	p.clearIsSet()
+	p.eachOption(func(c *Command, g *Group, option *Option) {
+		option.isSet = false
+		option.isSetDefault = false
+		option.updateDefaultLiteral()
+	})
 
 	// Add built-in help group to all commands if necessary
 	if (p.Options & HelpFlag) != None {
@@ -180,13 +217,15 @@ func (p *Parser) ParseArgs(args []string) ([]string, error) {
 
 	if len(compval) != 0 {
 		comp := &completion{parser: p}
+		items := comp.complete(args)
 
-		if compval == "verbose" {
-			comp.ShowDescriptions = true
+		if p.CompletionHandler != nil {
+			p.CompletionHandler(items)
+		} else {
+			comp.print(items, compval == "verbose")
+			os.Exit(0)
 		}
 
-		comp.execute(args)
-
 		return nil, nil
 	}
 
@@ -253,17 +292,13 @@ func (p *Parser) ParseArgs(args []string) ([]string, error) {
 	}
 
 	if s.err == nil {
-		p.eachCommand(func(c *Command) {
-			c.eachGroup(func(g *Group) {
-				for _, option := range g.options {
-					if option.isSet {
-						continue
-					}
+		p.eachOption(func(c *Command, g *Group, option *Option) {
+			if option.preventDefault {
+				return
+			}
 
-					option.clearDefault()
-				}
-			})
-		}, true)
+			option.clearDefault()
+		})
 
 		s.checkRequired(p)
 	}
@@ -275,12 +310,391 @@ func (p *Parser) ParseArgs(args []string) ([]string, error) {
 	} else if len(s.command.commands) != 0 && !s.command.SubcommandsOptional {
 		reterr = s.estimateCommand()
 	} else if cmd, ok := s.command.data.(Commander); ok {
-		reterr = cmd.Execute(s.retargs)
+		if p.CommandHandler != nil {
+			reterr = p.CommandHandler(cmd, s.retargs)
+		} else {
+			reterr = cmd.Execute(s.retargs)
+		}
+	} else if p.CommandHandler != nil {
+		reterr = p.CommandHandler(nil, s.retargs)
 	}
 
 	if reterr != nil {
-		return append([]string{s.arg}, s.args...), p.printError(reterr)
+		var retargs []string
+
+		if ourErr, ok := reterr.(*Error); !ok || ourErr.Type != ErrHelp {
+			retargs = append([]string{s.arg}, s.args...)
+		} else {
+			retargs = s.args
+		}
+
+		return retargs, p.printError(reterr)
 	}
 
 	return s.retargs, nil
 }
+
+func (p *parseState) eof() bool {
+	return len(p.args) == 0
+}
+
+func (p *parseState) pop() string {
+	if p.eof() {
+		return ""
+	}
+
+	p.arg = p.args[0]
+	p.args = p.args[1:]
+
+	return p.arg
+}
+
+func (p *parseState) peek() string {
+	if p.eof() {
+		return ""
+	}
+
+	return p.args[0]
+}
+
+func (p *parseState) checkRequired(parser *Parser) error {
+	c := parser.Command
+
+	var required []*Option
+
+	for c != nil {
+		c.eachGroup(func(g *Group) {
+			for _, option := range g.options {
+				if !option.isSet && option.Required {
+					required = append(required, option)
+				}
+			}
+		})
+
+		c = c.Active
+	}
+
+	if len(required) == 0 {
+		if len(p.positional) > 0 {
+			var reqnames []string
+
+			for _, arg := range p.positional {
+				argRequired := (!arg.isRemaining() && p.command.ArgsRequired) || arg.Required != -1 || arg.RequiredMaximum != -1
+
+				if !argRequired {
+					continue
+				}
+
+				if arg.isRemaining() {
+					if arg.value.Len() < arg.Required {
+						var arguments string
+
+						if arg.Required > 1 {
+							arguments = "arguments, but got only " + fmt.Sprintf("%d", arg.value.Len())
+						} else {
+							arguments = "argument"
+						}
+
+						reqnames = append(reqnames, "`"+arg.Name+" (at least "+fmt.Sprintf("%d", arg.Required)+" "+arguments+")`")
+					} else if arg.RequiredMaximum != -1 && arg.value.Len() > arg.RequiredMaximum {
+						if arg.RequiredMaximum == 0 {
+							reqnames = append(reqnames, "`"+arg.Name+" (zero arguments)`")
+						} else {
+							var arguments string
+
+							if arg.RequiredMaximum > 1 {
+								arguments = "arguments, but got " + fmt.Sprintf("%d", arg.value.Len())
+							} else {
+								arguments = "argument"
+							}
+
+							reqnames = append(reqnames, "`"+arg.Name+" (at most "+fmt.Sprintf("%d", arg.RequiredMaximum)+" "+arguments+")`")
+						}
+					}
+				} else {
+					reqnames = append(reqnames, "`"+arg.Name+"`")
+				}
+			}
+
+			if len(reqnames) == 0 {
+				return nil
+			}
+
+			var msg string
+
+			if len(reqnames) == 1 {
+				msg = fmt.Sprintf("the required argument %s was not provided", reqnames[0])
+			} else {
+				msg = fmt.Sprintf("the required arguments %s and %s were not provided",
+					strings.Join(reqnames[:len(reqnames)-1], ", "), reqnames[len(reqnames)-1])
+			}
+
+			p.err = newError(ErrRequired, msg)
+			return p.err
+		}
+
+		return nil
+	}
+
+	names := make([]string, 0, len(required))
+
+	for _, k := range required {
+		names = append(names, "`"+k.String()+"'")
+	}
+
+	sort.Strings(names)
+
+	var msg string
+
+	if len(names) == 1 {
+		msg = fmt.Sprintf("the required flag %s was not specified", names[0])
+	} else {
+		msg = fmt.Sprintf("the required flags %s and %s were not specified",
+			strings.Join(names[:len(names)-1], ", "), names[len(names)-1])
+	}
+
+	p.err = newError(ErrRequired, msg)
+	return p.err
+}
+
+func (p *parseState) estimateCommand() error {
+	commands := p.command.sortedVisibleCommands()
+	cmdnames := make([]string, len(commands))
+
+	for i, v := range commands {
+		cmdnames[i] = v.Name
+	}
+
+	var msg string
+	var errtype ErrorType
+
+	if len(p.retargs) != 0 {
+		c, l := closestChoice(p.retargs[0], cmdnames)
+		msg = fmt.Sprintf("Unknown command `%s'", p.retargs[0])
+		errtype = ErrUnknownCommand
+
+		if float32(l)/float32(len(c)) < 0.5 {
+			msg = fmt.Sprintf("%s, did you mean `%s'?", msg, c)
+		} else if len(cmdnames) == 1 {
+			msg = fmt.Sprintf("%s. You should use the %s command",
+				msg,
+				cmdnames[0])
+		} else if len(cmdnames) > 1 {
+			msg = fmt.Sprintf("%s. Please specify one command of: %s or %s",
+				msg,
+				strings.Join(cmdnames[:len(cmdnames)-1], ", "),
+				cmdnames[len(cmdnames)-1])
+		}
+	} else {
+		errtype = ErrCommandRequired
+
+		if len(cmdnames) == 1 {
+			msg = fmt.Sprintf("Please specify the %s command", cmdnames[0])
+		} else if len(cmdnames) > 1 {
+			msg = fmt.Sprintf("Please specify one command of: %s or %s",
+				strings.Join(cmdnames[:len(cmdnames)-1], ", "),
+				cmdnames[len(cmdnames)-1])
+		}
+	}
+
+	return newError(errtype, msg)
+}
+
+func (p *Parser) parseOption(s *parseState, name string, option *Option, canarg bool, argument *string) (err error) {
+	if !option.canArgument() {
+		if argument != nil {
+			return newErrorf(ErrNoArgumentForBool, "bool flag `%s' cannot have an argument", option)
+		}
+
+		err = option.set(nil)
+	} else if argument != nil || (canarg && !s.eof()) {
+		var arg string
+
+		if argument != nil {
+			arg = *argument
+		} else {
+			arg = s.pop()
+
+			if argumentIsOption(arg) && !(option.isSignedNumber() && len(arg) > 1 && arg[0] == '-' && arg[1] >= '0' && arg[1] <= '9') {
+				return newErrorf(ErrExpectedArgument, "expected argument for flag `%s', but got option `%s'", option, arg)
+			} else if p.Options&PassDoubleDash != 0 && arg == "--" {
+				return newErrorf(ErrExpectedArgument, "expected argument for flag `%s', but got double dash `--'", option)
+			}
+		}
+
+		if option.tag.Get("unquote") != "false" {
+			arg, err = unquoteIfPossible(arg)
+		}
+
+		if err == nil {
+			err = option.set(&arg)
+		}
+	} else if option.OptionalArgument {
+		option.empty()
+
+		for _, v := range option.OptionalValue {
+			err = option.set(&v)
+
+			if err != nil {
+				break
+			}
+		}
+	} else {
+		err = newErrorf(ErrExpectedArgument, "expected argument for flag `%s'", option)
+	}
+
+	if err != nil {
+		if _, ok := err.(*Error); !ok {
+			err = newErrorf(ErrMarshal, "invalid argument for flag `%s' (expected %s): %s",
+				option,
+				option.value.Type(),
+				err.Error())
+		}
+	}
+
+	return err
+}
+
+func (p *Parser) parseLong(s *parseState, name string, argument *string) error {
+	if option := s.lookup.longNames[name]; option != nil {
+		// Only long options that are required can consume an argument
+		// from the argument list
+		canarg := !option.OptionalArgument
+
+		return p.parseOption(s, name, option, canarg, argument)
+	}
+
+	return newErrorf(ErrUnknownFlag, "unknown flag `%s'", name)
+}
+
+func (p *Parser) splitShortConcatArg(s *parseState, optname string) (string, *string) {
+	c, n := utf8.DecodeRuneInString(optname)
+
+	if n == len(optname) {
+		return optname, nil
+	}
+
+	first := string(c)
+
+	if option := s.lookup.shortNames[first]; option != nil && option.canArgument() {
+		arg := optname[n:]
+		return first, &arg
+	}
+
+	return optname, nil
+}
+
+func (p *Parser) parseShort(s *parseState, optname string, argument *string) error {
+	if argument == nil {
+		optname, argument = p.splitShortConcatArg(s, optname)
+	}
+
+	for i, c := range optname {
+		shortname := string(c)
+
+		if option := s.lookup.shortNames[shortname]; option != nil {
+			// Only the last short argument can consume an argument from
+			// the arguments list, and only if it's non optional
+			canarg := (i+utf8.RuneLen(c) == len(optname)) && !option.OptionalArgument
+
+			if err := p.parseOption(s, shortname, option, canarg, argument); err != nil {
+				return err
+			}
+		} else {
+			return newErrorf(ErrUnknownFlag, "unknown flag `%s'", shortname)
+		}
+
+		// Only the first option can have a concatted argument, so just
+		// clear argument here
+		argument = nil
+	}
+
+	return nil
+}
+
+func (p *parseState) addArgs(args ...string) error {
+	for len(p.positional) > 0 && len(args) > 0 {
+		arg := p.positional[0]
+
+		if err := convert(args[0], arg.value, arg.tag); err != nil {
+			p.err = err
+			return err
+		}
+
+		if !arg.isRemaining() {
+			p.positional = p.positional[1:]
+		}
+
+		args = args[1:]
+	}
+
+	p.retargs = append(p.retargs, args...)
+	return nil
+}
+
+func (p *Parser) parseNonOption(s *parseState) error {
+	if len(s.positional) > 0 {
+		return s.addArgs(s.arg)
+	}
+
+	if len(s.command.commands) > 0 && len(s.retargs) == 0 {
+		if cmd := s.lookup.commands[s.arg]; cmd != nil {
+			s.command.Active = cmd
+			cmd.fillParseState(s)
+
+			return nil
+		} else if !s.command.SubcommandsOptional {
+			s.addArgs(s.arg)
+			return newErrorf(ErrUnknownCommand, "Unknown command `%s'", s.arg)
+		}
+	}
+
+	if (p.Options & PassAfterNonOption) != None {
+		// If PassAfterNonOption is set then all remaining arguments
+		// are considered positional
+		if err := s.addArgs(s.arg); err != nil {
+			return err
+		}
+
+		if err := s.addArgs(s.args...); err != nil {
+			return err
+		}
+
+		s.args = []string{}
+	} else {
+		return s.addArgs(s.arg)
+	}
+
+	return nil
+}
+
+func (p *Parser) showBuiltinHelp() error {
+	var b bytes.Buffer
+
+	p.WriteHelp(&b)
+	return newError(ErrHelp, b.String())
+}
+
+func (p *Parser) printError(err error) error {
+	if err != nil && (p.Options&PrintErrors) != None {
+		flagsErr, ok := err.(*Error)
+
+		if ok && flagsErr.Type == ErrHelp {
+			fmt.Fprintln(os.Stdout, err)
+		} else {
+			fmt.Fprintln(os.Stderr, err)
+		}
+	}
+
+	return err
+}
+
+func (p *Parser) clearIsSet() {
+	p.eachCommand(func(c *Command) {
+		c.eachGroup(func(g *Group) {
+			for _, option := range g.options {
+				option.isSet = false
+			}
+		})
+	}, true)
+}