syncthing/github.com/jessevdk/go-flags/parser_private.go
2013-12-23 11:18:46 -05:00

244 lines
5.4 KiB
Go

package flags
import (
"bytes"
"fmt"
"os"
"strings"
"unicode/utf8"
)
type parseState struct {
arg string
args []string
retargs []string
err error
command *Command
lookup lookup
}
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() error {
required := p.lookup.required
if len(required) == 0 {
return nil
}
names := make([]string, 0, len(required))
for k := range required {
names = append(names, "`"+k.String()+"'")
}
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.sortedCommands()
cmdnames := make([]string, len(commands))
for i, v := range commands {
cmdnames[i] = v.Name
}
var msg string
if len(p.retargs) != 0 {
c, l := closestChoice(p.retargs[0], cmdnames)
msg = fmt.Sprintf("Unknown command `%s'", p.retargs[0])
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 {
msg = fmt.Sprintf("%s. Please specify one command of: %s or %s",
msg,
strings.Join(cmdnames[:len(cmdnames)-1], ", "),
cmdnames[len(cmdnames)-1])
}
} else {
if len(cmdnames) == 1 {
msg = fmt.Sprintf("Please specify the %s command", cmdnames[0])
} else {
msg = fmt.Sprintf("Please specify one command of: %s or %s",
strings.Join(cmdnames[:len(cmdnames)-1], ", "),
cmdnames[len(cmdnames)-1])
}
}
return newError(ErrRequired, msg)
}
func (p *Parser) parseOption(s *parseState, name string, option *Option, canarg bool, argument *string) (retoption *Option, err error) {
if !option.canArgument() {
if argument != nil {
msg := fmt.Sprintf("bool flag `%s' cannot have an argument", option)
return option, newError(ErrNoArgumentForBool, msg)
}
err = option.set(nil)
} else if argument != nil {
err = option.set(argument)
} else if canarg && !s.eof() {
arg := s.pop()
err = option.set(&arg)
} else if option.OptionalArgument {
option.clear()
for _, v := range option.OptionalValue {
err = option.set(&v)
if err != nil {
break
}
}
} else {
msg := fmt.Sprintf("expected argument for flag `%s'", option)
err = newError(ErrExpectedArgument, msg)
}
if err != nil {
if _, ok := err.(*Error); !ok {
msg := fmt.Sprintf("invalid argument for flag `%s' (expected %s): %s",
option,
option.value.Type(),
err.Error())
err = newError(ErrMarshal, msg)
}
}
return option, err
}
func (p *Parser) parseLong(s *parseState, name string, argument *string) (option *Option, err 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 nil, newError(ErrUnknownFlag, fmt.Sprintf("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) (option *Option, err 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 option, err
}
} else {
return nil, newError(ErrUnknownFlag, fmt.Sprintf("unknown flag `%s'", shortname))
}
// Only the first option can have a concatted argument, so just
// clear argument here
argument = nil
}
return option, nil
}
func (p *Parser) parseNonOption(s *parseState) error {
if cmd := s.lookup.commands[s.arg]; cmd != nil {
if err := s.checkRequired(); err != nil {
return err
}
s.command.Active = cmd
s.command = cmd
s.lookup = cmd.makeLookup()
} else if (p.Options & PassAfterNonOption) != None {
// If PassAfterNonOption is set then all remaining arguments
// are considered positional
s.retargs = append(append(s.retargs, s.arg), s.args...)
s.args = []string{}
} else {
s.retargs = append(s.retargs, 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 {
fmt.Fprintln(os.Stderr, err)
}
return err
}