107 lines
2.8 KiB
Go
107 lines
2.8 KiB
Go
package cli
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import (
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"flag"
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"strings"
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)
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type iterativeParser interface {
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newFlagSet() (*flag.FlagSet, error)
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useShortOptionHandling() bool
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}
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// To enable short-option handling (e.g., "-it" vs "-i -t") we have to
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// iteratively catch parsing errors. This way we achieve LR parsing without
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// transforming any arguments. Otherwise, there is no way we can discriminate
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// combined short options from common arguments that should be left untouched.
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// Pass `shellComplete` to continue parsing options on failure during shell
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// completion when, the user-supplied options may be incomplete.
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func parseIter(set *flag.FlagSet, ip iterativeParser, args []string, shellComplete bool) error {
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for {
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err := set.Parse(args)
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if !ip.useShortOptionHandling() || err == nil {
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if shellComplete {
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return nil
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}
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return err
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}
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trimmed, trimErr := flagFromError(err)
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if trimErr != nil {
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return err
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}
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// regenerate the initial args with the split short opts
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argsWereSplit := false
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for i, arg := range args {
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// skip args that are not part of the error message
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if name := strings.TrimLeft(arg, "-"); name != trimmed {
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continue
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}
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// if we can't split, the error was accurate
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shortOpts := splitShortOptions(set, arg)
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if len(shortOpts) == 1 {
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return err
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}
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// swap current argument with the split version
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args = append(args[:i], append(shortOpts, args[i+1:]...)...)
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argsWereSplit = true
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break
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}
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// This should be an impossible to reach code path, but in case the arg
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// splitting failed to happen, this will prevent infinite loops
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if !argsWereSplit {
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return err
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}
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// Since custom parsing failed, replace the flag set before retrying
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newSet, err := ip.newFlagSet()
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if err != nil {
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return err
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}
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*set = *newSet
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}
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}
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const providedButNotDefinedErrMsg = "flag provided but not defined: -"
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// flagFromError tries to parse a provided flag from an error message. If the
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// parsing fials, it returns the input error and an empty string
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func flagFromError(err error) (string, error) {
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errStr := err.Error()
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trimmed := strings.TrimPrefix(errStr, providedButNotDefinedErrMsg)
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if errStr == trimmed {
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return "", err
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}
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return trimmed, nil
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}
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func splitShortOptions(set *flag.FlagSet, arg string) []string {
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shortFlagsExist := func(s string) bool {
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for _, c := range s[1:] {
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if f := set.Lookup(string(c)); f == nil {
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return false
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}
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}
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return true
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}
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if !isSplittable(arg) || !shortFlagsExist(arg) {
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return []string{arg}
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}
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separated := make([]string, 0, len(arg)-1)
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for _, flagChar := range arg[1:] {
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separated = append(separated, "-"+string(flagChar))
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}
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return separated
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}
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func isSplittable(flagArg string) bool {
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return strings.HasPrefix(flagArg, "-") && !strings.HasPrefix(flagArg, "--") && len(flagArg) > 2
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}
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