michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0:  * vim: set ts=8 sts=4 et sw=4 tw=99:
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "shell/jsoptparse.h"
michael@0: 
michael@0: #include <ctype.h>
michael@0: #include <stdarg.h>
michael@0: 
michael@0: #include "jsutil.h"
michael@0: 
michael@0: using namespace js;
michael@0: using namespace js::cli;
michael@0: using namespace js::cli::detail;
michael@0: 
michael@0: const char OptionParser::prognameMeta[] = "{progname}";
michael@0: 
michael@0: #define OPTION_CONVERT_IMPL(__cls) \
michael@0:     bool \
michael@0:     Option::is##__cls##Option() const \
michael@0:     { \
michael@0:         return kind == OptionKind##__cls; \
michael@0:     } \
michael@0:     __cls##Option * \
michael@0:     Option::as##__cls##Option() \
michael@0:     { \
michael@0:         JS_ASSERT(is##__cls##Option()); \
michael@0:         return static_cast<__cls##Option *>(this); \
michael@0:     } \
michael@0:     const __cls##Option * \
michael@0:     Option::as##__cls##Option() const \
michael@0:     { \
michael@0:         return const_cast<Option *>(this)->as##__cls##Option(); \
michael@0:     }
michael@0: 
michael@0: ValuedOption *
michael@0: Option::asValued()
michael@0: {
michael@0:     JS_ASSERT(isValued());
michael@0:     return static_cast<ValuedOption *>(this);
michael@0: }
michael@0: 
michael@0: const ValuedOption *
michael@0: Option::asValued() const
michael@0: {
michael@0:     return const_cast<Option *>(this)->asValued();
michael@0: }
michael@0: 
michael@0: OPTION_CONVERT_IMPL(Bool)
michael@0: OPTION_CONVERT_IMPL(String)
michael@0: OPTION_CONVERT_IMPL(Int)
michael@0: OPTION_CONVERT_IMPL(MultiString)
michael@0: 
michael@0: void
michael@0: OptionParser::setArgTerminatesOptions(const char *name, bool enabled)
michael@0: {
michael@0:     findArgument(name)->setTerminatesOptions(enabled);
michael@0: }
michael@0: 
michael@0: void
michael@0: OptionParser::setArgCapturesRest(const char *name)
michael@0: {
michael@0:     MOZ_ASSERT(restArgument == -1, "only one argument may be set to capture the rest");
michael@0:     restArgument = findArgumentIndex(name);
michael@0:     MOZ_ASSERT(restArgument != -1, "unknown argument name passed to setArgCapturesRest");
michael@0: }
michael@0: 
michael@0: OptionParser::Result
michael@0: OptionParser::error(const char *fmt, ...)
michael@0: {
michael@0:     va_list args;
michael@0:     va_start(args, fmt);
michael@0:     fprintf(stderr, "Error: ");
michael@0:     vfprintf(stderr, fmt, args);
michael@0:     va_end(args);
michael@0:     fputs("\n\n", stderr);
michael@0:     return ParseError;
michael@0: }
michael@0: 
michael@0: /* Quick and dirty paragraph printer. */
michael@0: static void
michael@0: PrintParagraph(const char *text, unsigned startColno, const unsigned limitColno, bool padFirstLine)
michael@0: {
michael@0:     unsigned colno = startColno;
michael@0:     const char *it = text;
michael@0: 
michael@0:     if (padFirstLine)
michael@0:         printf("%*s", startColno, "");
michael@0: 
michael@0:     while (*it != '\0') {
michael@0:         JS_ASSERT(!isspace(*it));
michael@0: 
michael@0:         /* Delimit the current token. */
michael@0:         const char *limit = it;
michael@0:         while (!isspace(*limit) && *limit != '\0')
michael@0:             ++limit;
michael@0: 
michael@0:         /*
michael@0:          * If the current token is longer than the available number of columns,
michael@0:          * then make a line break before printing the token.
michael@0:          */
michael@0:         JS_ASSERT(limit - it > 0);
michael@0:         size_t tokLen = limit - it;
michael@0:         JS_ASSERT(tokLen);
michael@0:         if (tokLen + colno >= limitColno) {
michael@0:             printf("\n%*s%.*s", startColno, "", int(tokLen), it);
michael@0:             colno = startColno + tokLen;
michael@0:         } else {
michael@0:             printf("%.*s", int(tokLen), it);
michael@0:             colno += tokLen;
michael@0:         }
michael@0: 
michael@0:         switch (*limit) {
michael@0:           case '\0':
michael@0:             return;
michael@0:           case ' ':
michael@0:             putchar(' ');
michael@0:             colno += 1;
michael@0:             it = limit;
michael@0:             while (*it == ' ')
michael@0:                 ++it;
michael@0:             break;
michael@0:           case '\n':
michael@0:             /* |text| wants to force a newline here. */
michael@0:             printf("\n%*s", startColno, "");
michael@0:             colno = startColno;
michael@0:             it = limit + 1;
michael@0:             /* Could also have line-leading spaces. */
michael@0:             while (*it == ' ') {
michael@0:                 putchar(' ');
michael@0:                 ++colno;
michael@0:                 ++it;
michael@0:             }
michael@0:             break;
michael@0:           default:
michael@0:             MOZ_ASSUME_UNREACHABLE("unhandled token splitting character in text");
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: static const char *
michael@0: OptionFlagsToFormatInfo(char shortflag, bool isValued, size_t *length)
michael@0: {
michael@0:     static const char * const fmt[4] = { "  -%c --%s ",
michael@0:                                          "  --%s ",
michael@0:                                          "  -%c --%s=%s ",
michael@0:                                          "  --%s=%s " };
michael@0: 
michael@0:     /* How mny chars w/o longflag? */
michael@0:     size_t lengths[4] = { strlen(fmt[0]) - 3,
michael@0:                           strlen(fmt[1]) - 3,
michael@0:                           strlen(fmt[2]) - 5,
michael@0:                           strlen(fmt[3]) - 5 };
michael@0:     int index = isValued ? 2 : 0;
michael@0:     if (!shortflag)
michael@0:         index++;
michael@0: 
michael@0:     *length = lengths[index];
michael@0:     return fmt[index];
michael@0: }
michael@0: 
michael@0: OptionParser::Result
michael@0: OptionParser::printHelp(const char *progname)
michael@0: {
michael@0:     const char *prefixEnd = strstr(usage, prognameMeta);
michael@0:     if (prefixEnd) {
michael@0:         printf("%.*s%s%s\n", int(prefixEnd - usage), usage, progname,
michael@0:                prefixEnd + sizeof(prognameMeta) - 1);
michael@0:     } else {
michael@0:         puts(usage);
michael@0:     }
michael@0: 
michael@0:     if (descr) {
michael@0:         putchar('\n');
michael@0:         PrintParagraph(descr, 2, descrWidth, true);
michael@0:         putchar('\n');
michael@0:     }
michael@0: 
michael@0:     if (ver)
michael@0:         printf("\nVersion: %s\n\n", ver);
michael@0: 
michael@0:     if (!arguments.empty()) {
michael@0:         printf("Arguments:\n");
michael@0: 
michael@0:         static const char fmt[] = "  %s ";
michael@0:         size_t fmtChars = sizeof(fmt) - 2;
michael@0:         size_t lhsLen = 0;
michael@0:         for (Option **it = arguments.begin(), **end = arguments.end(); it != end; ++it)
michael@0:             lhsLen = Max(lhsLen, strlen((*it)->longflag) + fmtChars);
michael@0: 
michael@0:         for (Option **it = arguments.begin(), **end = arguments.end(); it != end; ++it) {
michael@0:             Option *arg = *it;
michael@0:             size_t chars = printf(fmt, arg->longflag);
michael@0:             for (; chars < lhsLen; ++chars)
michael@0:                 putchar(' ');
michael@0:             PrintParagraph(arg->help, lhsLen, helpWidth, false);
michael@0:             putchar('\n');
michael@0:         }
michael@0:         putchar('\n');
michael@0:     }
michael@0: 
michael@0:     if (!options.empty()) {
michael@0:         printf("Options:\n");
michael@0: 
michael@0:         /* Calculate sizes for column alignment. */
michael@0:         size_t lhsLen = 0;
michael@0:         for (Option **it = options.begin(), **end = options.end(); it != end; ++it) {
michael@0:             Option *opt = *it;
michael@0:             size_t longflagLen = strlen(opt->longflag);
michael@0: 
michael@0:             size_t fmtLen;
michael@0:             OptionFlagsToFormatInfo(opt->shortflag, opt->isValued(), &fmtLen);
michael@0: 
michael@0:             size_t len = fmtLen + longflagLen;
michael@0:             if (opt->isValued())
michael@0:                 len += strlen(opt->asValued()->metavar);
michael@0:             lhsLen = Max(lhsLen, len);
michael@0:         }
michael@0: 
michael@0:         /* Print option help text. */
michael@0:         for (Option **it = options.begin(), **end = options.end(); it != end; ++it) {
michael@0:             Option *opt = *it;
michael@0:             size_t fmtLen;
michael@0:             const char *fmt = OptionFlagsToFormatInfo(opt->shortflag, opt->isValued(), &fmtLen);
michael@0:             size_t chars;
michael@0:             if (opt->isValued()) {
michael@0:                 if (opt->shortflag)
michael@0:                     chars = printf(fmt, opt->shortflag, opt->longflag, opt->asValued()->metavar);
michael@0:                 else
michael@0:                     chars = printf(fmt, opt->longflag, opt->asValued()->metavar);
michael@0:             } else {
michael@0:                 if (opt->shortflag)
michael@0:                     chars = printf(fmt, opt->shortflag, opt->longflag);
michael@0:                 else
michael@0:                     chars = printf(fmt, opt->longflag);
michael@0:             }
michael@0:             for (; chars < lhsLen; ++chars)
michael@0:                 putchar(' ');
michael@0:             PrintParagraph(opt->help, lhsLen, helpWidth, false);
michael@0:             putchar('\n');
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     return ParseHelp;
michael@0: }
michael@0: 
michael@0: OptionParser::Result
michael@0: OptionParser::extractValue(size_t argc, char **argv, size_t *i, char **value)
michael@0: {
michael@0:     JS_ASSERT(*i < argc);
michael@0:     char *eq = strchr(argv[*i], '=');
michael@0:     if (eq) {
michael@0:         *value = eq + 1;
michael@0:         if (*value[0] == '\0')
michael@0:             return error("A value is required for option %.*s", eq - argv[*i], argv[*i]);
michael@0:         return Okay;
michael@0:     }
michael@0: 
michael@0:     if (argc == *i + 1)
michael@0:         return error("Expected a value for option %s", argv[*i]);
michael@0: 
michael@0:     *i += 1;
michael@0:     *value = argv[*i];
michael@0:     return Okay;
michael@0: }
michael@0: 
michael@0: OptionParser::Result
michael@0: OptionParser::handleOption(Option *opt, size_t argc, char **argv, size_t *i, bool *optionsAllowed)
michael@0: {
michael@0:     if (opt->getTerminatesOptions())
michael@0:         *optionsAllowed = false;
michael@0: 
michael@0:     switch (opt->kind) {
michael@0:       case OptionKindBool:
michael@0:       {
michael@0:         if (opt == &helpOption)
michael@0:             return printHelp(argv[0]);
michael@0:         opt->asBoolOption()->value = true;
michael@0:         return Okay;
michael@0:       }
michael@0:       /*
michael@0:        * Valued options are allowed to specify their values either via
michael@0:        * successive arguments or a single --longflag=value argument.
michael@0:        */
michael@0:       case OptionKindString:
michael@0:       {
michael@0:         char *value = nullptr;
michael@0:         if (Result r = extractValue(argc, argv, i, &value))
michael@0:             return r;
michael@0:         opt->asStringOption()->value = value;
michael@0:         return Okay;
michael@0:       }
michael@0:       case OptionKindInt:
michael@0:       {
michael@0:         char *value = nullptr;
michael@0:         if (Result r = extractValue(argc, argv, i, &value))
michael@0:             return r;
michael@0:         opt->asIntOption()->value = atoi(value);
michael@0:         return Okay;
michael@0:       }
michael@0:       case OptionKindMultiString:
michael@0:       {
michael@0:         char *value = nullptr;
michael@0:         if (Result r = extractValue(argc, argv, i, &value))
michael@0:             return r;
michael@0:         StringArg arg(value, *i);
michael@0:         return opt->asMultiStringOption()->strings.append(arg) ? Okay : Fail;
michael@0:       }
michael@0:       default:
michael@0:         MOZ_ASSUME_UNREACHABLE("unhandled option kind");
michael@0:     }
michael@0: }
michael@0: 
michael@0: OptionParser::Result
michael@0: OptionParser::handleArg(size_t argc, char **argv, size_t *i, bool *optionsAllowed)
michael@0: {
michael@0:     if (nextArgument >= arguments.length())
michael@0:         return error("Too many arguments provided");
michael@0: 
michael@0:     Option *arg = arguments[nextArgument];
michael@0: 
michael@0:     if (arg->getTerminatesOptions())
michael@0:         *optionsAllowed = false;
michael@0: 
michael@0:     switch (arg->kind) {
michael@0:       case OptionKindString:
michael@0:         arg->asStringOption()->value = argv[*i];
michael@0:         nextArgument += 1;
michael@0:         return Okay;
michael@0:       case OptionKindMultiString:
michael@0:       {
michael@0:         /* Don't advance the next argument -- there can only be one (final) variadic argument. */
michael@0:         StringArg value(argv[*i], *i);
michael@0:         return arg->asMultiStringOption()->strings.append(value) ? Okay : Fail;
michael@0:       }
michael@0:       default:
michael@0:         MOZ_ASSUME_UNREACHABLE("unhandled argument kind");
michael@0:     }
michael@0: }
michael@0: 
michael@0: OptionParser::Result
michael@0: OptionParser::parseArgs(int inputArgc, char **argv)
michael@0: {
michael@0:     JS_ASSERT(inputArgc >= 0);
michael@0:     size_t argc = inputArgc;
michael@0:     /* Permit a "no more options" capability, like |--| offers in many shell interfaces. */
michael@0:     bool optionsAllowed = true;
michael@0: 
michael@0:     for (size_t i = 1; i < argc; ++i) {
michael@0:         char *arg = argv[i];
michael@0:         Result r;
michael@0:         /* Note: solo dash option is actually a 'stdin' argument. */
michael@0:         if (arg[0] == '-' && arg[1] != '\0' && optionsAllowed) {
michael@0:             /* Option. */
michael@0:             Option *opt;
michael@0:             if (arg[1] == '-') {
michael@0:                 if (arg[2] == '\0') {
michael@0:                     /* End of options */
michael@0:                     optionsAllowed = false;
michael@0:                     nextArgument = restArgument;
michael@0:                     continue;
michael@0:                 } else {
michael@0:                     /* Long option. */
michael@0:                     opt = findOption(arg + 2);
michael@0:                     if (!opt)
michael@0:                         return error("Invalid long option: %s", arg);
michael@0:                 }
michael@0:             } else {
michael@0:                 /* Short option */
michael@0:                 if (arg[2] != '\0')
michael@0:                     return error("Short option followed by junk: %s", arg);
michael@0:                 opt = findOption(arg[1]);
michael@0:                 if (!opt)
michael@0:                     return error("Invalid short option: %s", arg);
michael@0:             }
michael@0: 
michael@0:             r = handleOption(opt, argc, argv, &i, &optionsAllowed);
michael@0:         } else {
michael@0:             /* Argument. */
michael@0:             r = handleArg(argc, argv, &i, &optionsAllowed);
michael@0:         }
michael@0: 
michael@0:         if (r != Okay)
michael@0:             return r;
michael@0:     }
michael@0:     return Okay;
michael@0: }
michael@0: 
michael@0: void
michael@0: OptionParser::setHelpOption(char shortflag, const char *longflag, const char *help)
michael@0: {
michael@0:     helpOption.setFlagInfo(shortflag, longflag, help);
michael@0: }
michael@0: 
michael@0: bool
michael@0: OptionParser::getHelpOption() const
michael@0: {
michael@0:     return helpOption.value;
michael@0: }
michael@0: 
michael@0: bool
michael@0: OptionParser::getBoolOption(char shortflag) const
michael@0: {
michael@0:     return findOption(shortflag)->asBoolOption()->value;
michael@0: }
michael@0: 
michael@0: int
michael@0: OptionParser::getIntOption(char shortflag) const
michael@0: {
michael@0:     return findOption(shortflag)->asIntOption()->value;
michael@0: }
michael@0: 
michael@0: const char *
michael@0: OptionParser::getStringOption(char shortflag) const
michael@0: {
michael@0:     return findOption(shortflag)->asStringOption()->value;
michael@0: }
michael@0: 
michael@0: MultiStringRange
michael@0: OptionParser::getMultiStringOption(char shortflag) const
michael@0: {
michael@0:     const MultiStringOption *mso = findOption(shortflag)->asMultiStringOption();
michael@0:     return MultiStringRange(mso->strings.begin(), mso->strings.end());
michael@0: }
michael@0: 
michael@0: bool
michael@0: OptionParser::getBoolOption(const char *longflag) const
michael@0: {
michael@0:     return findOption(longflag)->asBoolOption()->value;
michael@0: }
michael@0: 
michael@0: int
michael@0: OptionParser::getIntOption(const char *longflag) const
michael@0: {
michael@0:     return findOption(longflag)->asIntOption()->value;
michael@0: }
michael@0: 
michael@0: const char *
michael@0: OptionParser::getStringOption(const char *longflag) const
michael@0: {
michael@0:     return findOption(longflag)->asStringOption()->value;
michael@0: }
michael@0: 
michael@0: MultiStringRange
michael@0: OptionParser::getMultiStringOption(const char *longflag) const
michael@0: {
michael@0:     const MultiStringOption *mso = findOption(longflag)->asMultiStringOption();
michael@0:     return MultiStringRange(mso->strings.begin(), mso->strings.end());
michael@0: }
michael@0: 
michael@0: OptionParser::~OptionParser()
michael@0: {
michael@0:     for (Option **it = options.begin(), **end = options.end(); it != end; ++it)
michael@0:         js_delete<Option>(*it);
michael@0:     for (Option **it = arguments.begin(), **end = arguments.end(); it != end; ++it)
michael@0:         js_delete<Option>(*it);
michael@0: }
michael@0: 
michael@0: Option *
michael@0: OptionParser::findOption(char shortflag)
michael@0: {
michael@0:     for (Option **it = options.begin(), **end = options.end(); it != end; ++it) {
michael@0:         if ((*it)->shortflag == shortflag)
michael@0:             return *it;
michael@0:     }
michael@0: 
michael@0:     return helpOption.shortflag == shortflag ? &helpOption : nullptr;
michael@0: }
michael@0: 
michael@0: const Option *
michael@0: OptionParser::findOption(char shortflag) const
michael@0: {
michael@0:     return const_cast<OptionParser *>(this)->findOption(shortflag);
michael@0: }
michael@0: 
michael@0: Option *
michael@0: OptionParser::findOption(const char *longflag)
michael@0: {
michael@0:     for (Option **it = options.begin(), **end = options.end(); it != end; ++it) {
michael@0:         const char *target = (*it)->longflag;
michael@0:         if ((*it)->isValued()) {
michael@0:             size_t targetLen = strlen(target);
michael@0:             /* Permit a trailing equals sign on the longflag argument. */
michael@0:             for (size_t i = 0; i < targetLen; ++i) {
michael@0:                 if (longflag[i] == '\0' || longflag[i] != target[i])
michael@0:                     goto no_match;
michael@0:             }
michael@0:             if (longflag[targetLen] == '\0' || longflag[targetLen] == '=')
michael@0:                 return *it;
michael@0:         } else {
michael@0:             if (strcmp(target, longflag) == 0)
michael@0:                 return *it;
michael@0:         }
michael@0:   no_match:;
michael@0:     }
michael@0: 
michael@0:     return strcmp(helpOption.longflag, longflag) ? nullptr : &helpOption;
michael@0: }
michael@0: 
michael@0: const Option *
michael@0: OptionParser::findOption(const char *longflag) const
michael@0: {
michael@0:     return const_cast<OptionParser *>(this)->findOption(longflag);
michael@0: }
michael@0: 
michael@0: /* Argument accessors */
michael@0: 
michael@0: int
michael@0: OptionParser::findArgumentIndex(const char *name) const
michael@0: {
michael@0:     for (Option * const *it = arguments.begin(); it != arguments.end(); ++it) {
michael@0:         const char *target = (*it)->longflag;
michael@0:         if (strcmp(target, name) == 0)
michael@0:             return it - arguments.begin();
michael@0:     }
michael@0:     return -1;
michael@0: }
michael@0: 
michael@0: Option *
michael@0: OptionParser::findArgument(const char *name)
michael@0: {
michael@0:     int index = findArgumentIndex(name);
michael@0:     return (index == -1) ? nullptr : arguments[index];
michael@0: }
michael@0: 
michael@0: const Option *
michael@0: OptionParser::findArgument(const char *name) const
michael@0: {
michael@0:     int index = findArgumentIndex(name);
michael@0:     return (index == -1) ? nullptr : arguments[index];
michael@0: }
michael@0: 
michael@0: const char *
michael@0: OptionParser::getStringArg(const char *name) const
michael@0: {
michael@0:     return findArgument(name)->asStringOption()->value;
michael@0: }
michael@0: 
michael@0: MultiStringRange
michael@0: OptionParser::getMultiStringArg(const char *name) const
michael@0: {
michael@0:     const MultiStringOption *mso = findArgument(name)->asMultiStringOption();
michael@0:     return MultiStringRange(mso->strings.begin(), mso->strings.end());
michael@0: }
michael@0: 
michael@0: /* Option builders */
michael@0: 
michael@0: bool
michael@0: OptionParser::addIntOption(char shortflag, const char *longflag, const char *metavar,
michael@0:                            const char *help, int defaultValue)
michael@0: {
michael@0:     if (!options.reserve(options.length() + 1))
michael@0:         return false;
michael@0:     IntOption *io = js_new<IntOption>(shortflag, longflag, help, metavar, defaultValue);
michael@0:     if (!io)
michael@0:         return false;
michael@0:     options.infallibleAppend(io);
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: bool
michael@0: OptionParser::addBoolOption(char shortflag, const char *longflag, const char *help)
michael@0: {
michael@0:     if (!options.reserve(options.length() + 1))
michael@0:         return false;
michael@0:     BoolOption *bo = js_new<BoolOption>(shortflag, longflag, help);
michael@0:     if (!bo)
michael@0:         return false;
michael@0:     options.infallibleAppend(bo);
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: bool
michael@0: OptionParser::addStringOption(char shortflag, const char *longflag, const char *metavar,
michael@0:                               const char *help)
michael@0: {
michael@0:     if (!options.reserve(options.length() + 1))
michael@0:         return false;
michael@0:     StringOption *so = js_new<StringOption>(shortflag, longflag, help, metavar);
michael@0:     if (!so)
michael@0:         return false;
michael@0:     options.infallibleAppend(so);
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: bool
michael@0: OptionParser::addMultiStringOption(char shortflag, const char *longflag, const char *metavar,
michael@0:                                    const char *help)
michael@0: {
michael@0:     if (!options.reserve(options.length() + 1))
michael@0:         return false;
michael@0:     MultiStringOption *mso = js_new<MultiStringOption>(shortflag, longflag, help, metavar);
michael@0:     if (!mso)
michael@0:         return false;
michael@0:     options.infallibleAppend(mso);
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: /* Argument builders */
michael@0: 
michael@0: bool
michael@0: OptionParser::addOptionalStringArg(const char *name, const char *help)
michael@0: {
michael@0:     if (!arguments.reserve(arguments.length() + 1))
michael@0:         return false;
michael@0:     StringOption *so = js_new<StringOption>(1, name, help, (const char *) nullptr);
michael@0:     if (!so)
michael@0:         return false;
michael@0:     arguments.infallibleAppend(so);
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: bool
michael@0: OptionParser::addOptionalMultiStringArg(const char *name, const char *help)
michael@0: {
michael@0:     JS_ASSERT_IF(!arguments.empty(), !arguments.back()->isVariadic());
michael@0:     if (!arguments.reserve(arguments.length() + 1))
michael@0:         return false;
michael@0:     MultiStringOption *mso = js_new<MultiStringOption>(1, name, help, (const char *) nullptr);
michael@0:     if (!mso)
michael@0:         return false;
michael@0:     arguments.infallibleAppend(mso);
michael@0:     return true;
michael@0: }