Userland+AK: Stop using getopt() for ArgsParser

This commit moves the implementation of getopt into AK, and converts its
API to understand and use StringView instead of char*.
Everything else is caught in the crossfire of making
Option::accept_value() take a StringView instead of a char const*.

With this, we must now pass a Span<StringView> to ArgsParser::parse(),
applications using LibMain are unaffected, but anything not using that
or taking its own argc/argv has to construct a Vector<StringView> for
this method.

7 files changed, 150 insertions, 419 deletions

diff --git a/Userland/Libraries/LibC/getopt.cpp b/Userland/Libraries/LibC/getopt.cpp
index c588aff02d..6e8d1a09e9 100644
--- a/Userland/Libraries/LibC/getopt.cpp
+++ b/Userland/Libraries/LibC/getopt.cpp
@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <AK/OptionParser.h>
 #include <AK/StringView.h>
 #include <AK/Vector.h>
 #include <getopt.h>
@@ -20,338 +21,74 @@ char* optarg = nullptr;
 // POSIX says, "When an element of argv[] contains multiple option characters,
 // it is unspecified how getopt() determines which options have already been
 // processed". Well, this is how we do it.
-static size_t s_index_into_multioption_argument = 0;
-
-[[gnu::format(printf, 1, 2)]] static inline void report_error(char const* format, ...)
-{
-    if (!opterr)
-        return;
-
-    fputs("\033[31m", stderr);
-
-    va_list ap;
-    va_start(ap, format);
-    vfprintf(stderr, format, ap);
-    va_end(ap);
-
-    fputs("\033[0m\n", stderr);
-}
-
 namespace {
-
-class OptionParser {
-public:
-    OptionParser(int argc, char* const* argv, StringView short_options, option const* long_options, int* out_long_option_index = nullptr);
-    int getopt();
-
-private:
-    bool lookup_short_option(char option, int& needs_value) const;
-    int handle_short_option();
-
-    option const* lookup_long_option(char* raw) const;
-    int handle_long_option();
-
-    void shift_argv();
-    bool find_next_option();
-
-    StringView current_arg() const
-    {
-        auto const* arg_ptr = m_argv[m_arg_index];
-        if (arg_ptr == NULL)
-            return {};
-        return { arg_ptr, strlen(arg_ptr) };
-    }
-
-    size_t m_argc { 0 };
-    char* const* m_argv { nullptr };
-    StringView m_short_options;
-    option const* m_long_options { nullptr };
-    int* m_out_long_option_index { nullptr };
-    bool m_stop_on_first_non_option { false };
-
-    size_t m_arg_index { 0 };
-    size_t m_consumed_args { 0 };
-};
-
-OptionParser::OptionParser(int argc, char* const* argv, StringView short_options, option const* long_options, int* out_long_option_index)
-    : m_argc(argc)
-    , m_argv(argv)
-    , m_short_options(short_options)
-    , m_long_options(long_options)
-    , m_out_long_option_index(out_long_option_index)
-{
-    // In the following case:
-    // $ foo bar -o baz
-    // we want to parse the option (-o baz) first, and leave the argument (bar)
-    // in argv after we return -1 when invoked the second time. So we reorder
-    // argv to put options first and positional arguments next. To turn this
-    // behavior off, start the short options spec with a "+". This is a GNU
-    // extension that we support.
-    m_stop_on_first_non_option = short_options.starts_with('+');
-
-    // See if we should reset the internal state.
-    if (optreset || optind == 0) {
-        optreset = 0;
-        optind = 1;
-        s_index_into_multioption_argument = 0;
-    }
-
-    optopt = 0;
-    optarg = nullptr;
-}
-
-int OptionParser::getopt()
-{
-    bool should_reorder_argv = !m_stop_on_first_non_option;
-    int res = -1;
-
-    bool found_an_option = find_next_option();
-    auto arg = current_arg();
-
-    if (!found_an_option) {
-        res = -1;
-        if (arg == "--")
-            m_consumed_args = 1;
-        else
-            m_consumed_args = 0;
-    } else {
-        // Alright, so we have an option on our hands!
-        bool is_long_option = arg.starts_with("--"sv);
-        if (is_long_option)
-            res = handle_long_option();
-        else
-            res = handle_short_option();
-
-        // If we encountered an error, return immediately.
-        if (res == '?')
-            return '?';
-    }
-
-    if (should_reorder_argv)
-        shift_argv();
-    else
-        VERIFY(optind == static_cast<int>(m_arg_index));
-    optind += m_consumed_args;
-
-    return res;
-}
-
-bool OptionParser::lookup_short_option(char option, int& needs_value) const
-{
-    Vector<StringView> parts = m_short_options.split_view(option, SplitBehavior::KeepEmpty);
-
-    VERIFY(parts.size() <= 2);
-    if (parts.size() < 2) {
-        // Haven't found the option in the spec.
-        return false;
-    }
-
-    if (parts[1].starts_with("::"sv)) {
-        // If an option is followed by two colons, it optionally accepts an
-        // argument.
-        needs_value = optional_argument;
-    } else if (parts[1].starts_with(':')) {
-        // If it's followed by one colon, it requires an argument.
-        needs_value = required_argument;
-    } else {
-        // Otherwise, it doesn't accept arguments.
-        needs_value = no_argument;
-    }
-    return true;
-}
-
-int OptionParser::handle_short_option()
-{
-    StringView arg = current_arg();
-    VERIFY(arg.starts_with('-'));
-
-    if (s_index_into_multioption_argument == 0) {
-        // Just starting to parse this argument, skip the "-".
-        s_index_into_multioption_argument = 1;
-    }
-    char option = arg[s_index_into_multioption_argument];
-    s_index_into_multioption_argument++;
-
-    int needs_value = no_argument;
-    bool ok = lookup_short_option(option, needs_value);
-    if (!ok) {
-        optopt = option;
-        report_error("Unrecognized option \033[1m-%c\033[22m", option);
-        return '?';
-    }
-
-    // Let's see if we're at the end of this argument already.
-    if (s_index_into_multioption_argument < arg.length()) {
-        // This not yet the end.
-        if (needs_value == no_argument) {
-            optarg = nullptr;
-            m_consumed_args = 0;
-        } else {
-            // Treat the rest of the argument as the value, the "-ovalue"
-            // syntax.
-            optarg = m_argv[m_arg_index] + s_index_into_multioption_argument;
-            // Next time, process the next argument.
-            s_index_into_multioption_argument = 0;
-            m_consumed_args = 1;
-        }
-    } else {
-        s_index_into_multioption_argument = 0;
-        if (needs_value != required_argument) {
-            optarg = nullptr;
-            m_consumed_args = 1;
-        } else if (m_arg_index + 1 < m_argc) {
-            // Treat the next argument as a value, the "-o value" syntax.
-            optarg = m_argv[m_arg_index + 1];
-            m_consumed_args = 2;
-        } else {
-            report_error("Missing value for option \033[1m-%c\033[22m", option);
-            return '?';
-        }
-    }
-
-    return option;
-}
-
-option const* OptionParser::lookup_long_option(char* raw) const
-{
-    StringView arg { raw, strlen(raw) };
-
-    for (size_t index = 0; m_long_options[index].name; index++) {
-        auto& option = m_long_options[index];
-        StringView name { option.name, strlen(option.name) };
-
-        if (!arg.starts_with(name))
-            continue;
-
-        // It would be better to not write out the index at all unless we're
-        // sure we've found the right option, but whatever.
-        if (m_out_long_option_index)
-            *m_out_long_option_index = index;
-
-        // Can either be "--option" or "--option=value".
-        if (arg.length() == name.length()) {
-            optarg = nullptr;
-            return &option;
-        }
-        VERIFY(arg.length() > name.length());
-        if (arg[name.length()] == '=') {
-            optarg = raw + name.length() + 1;
-            return &option;
-        }
-    }
-
-    return nullptr;
+Vector<StringView> s_args;
+OptionParser s_parser;
 }
 
-int OptionParser::handle_long_option()
+int getopt(int argc, char* const* argv, char const* short_options)
 {
-    VERIFY(current_arg().starts_with("--"sv));
+    s_args.clear_with_capacity();
+    s_args.ensure_capacity(argc);
+    for (auto i = 1; i < argc; ++i)
+        s_args.append({ argv[i], strlen(argv[i]) });
 
-    // We cannot set optopt to anything sensible for long options, so set it to 0.
-    optopt = 0;
-
-    auto* option = lookup_long_option(m_argv[m_arg_index] + 2);
-    if (!option) {
-        report_error("Unrecognized option \033[1m%s\033[22m", m_argv[m_arg_index]);
-        return '?';
+    if (optind == 0 || optreset == 1) {
+        s_parser.reset_state();
+        optind = 1;
+        optreset = 0;
     }
-    // lookup_long_option() will also set optarg if the value of the option is
-    // specified using "--option=value" syntax.
 
-    // Figure out whether this option needs and/or has a value (also called "an
-    // argument", but let's not call it that to distinguish it from argv
-    // elements).
-    switch (option->has_arg) {
-    case no_argument:
-        if (optarg) {
-            report_error("Option \033[1m--%s\033[22m doesn't accept an argument", option->name);
-            return '?';
-        }
-        m_consumed_args = 1;
-        break;
-    case optional_argument:
-        m_consumed_args = 1;
-        break;
-    case required_argument:
-        if (optarg) {
-            // Value specified using "--option=value" syntax.
-            m_consumed_args = 1;
-        } else if (m_arg_index + 1 < m_argc) {
-            // Treat the next argument as a value in "--option value" syntax.
-            optarg = m_argv[m_arg_index + 1];
-            m_consumed_args = 2;
-        } else {
-            report_error("Missing value for option \033[1m--%s\033[22m", option->name);
-            return '?';
-        }
-        break;
-    default:
-        VERIFY_NOT_REACHED();
-    }
+    auto result = s_parser.getopt(s_args.span(), { short_options, strlen(short_options) }, {}, {});
 
-    // Now that we've figured the value out, see about reporting this option to
-    // our caller.
-    if (option->flag) {
-        *option->flag = option->val;
-        return 0;
-    }
-    return option->val;
+    optind += result.consumed_args;
+    optarg = result.optarg_value.map([](auto x) { return const_cast<char*>(x.characters_without_null_termination()); }).value_or(optarg);
+    optopt = result.optopt_value.value_or(optopt);
+    return result.result;
 }
 
-void OptionParser::shift_argv()
+int getopt_long(int argc, char* const* argv, char const* short_options, const struct option* long_options, int* out_long_option_index)
 {
-    // We've just parsed an option (which perhaps has a value).
-    // Put the option (along with it value, if any) in front of other arguments.
-    VERIFY(optind <= static_cast<int>(m_arg_index));
-
-    if (optind == static_cast<int>(m_arg_index) || m_consumed_args == 0) {
-        // Nothing to do!
-        return;
+    s_args.clear_with_capacity();
+    s_args.ensure_capacity(argc);
+    for (auto i = 1; i < argc; ++i)
+        s_args.append({ argv[i], strlen(argv[i]) });
+
+    size_t long_option_count = 0;
+    for (auto option = long_options; option && option->name; option += 1)
+        long_option_count++;
+
+    Vector<OptionParser::Option> translated_long_options;
+    translated_long_options.ensure_capacity(long_option_count);
+    for (size_t i = 0; i < long_option_count; ++i) {
+        auto option = &long_options[i];
+
+        translated_long_options.append(OptionParser::Option {
+            .name = { option->name, strlen(option->name) },
+            .requirement = option->has_arg == no_argument
+                ? AK::OptionParser::ArgumentRequirement::NoArgument
+                : option->has_arg == optional_argument
+                ? AK::OptionParser::ArgumentRequirement::HasOptionalArgument
+                : AK::OptionParser::ArgumentRequirement::HasRequiredArgument,
+            .flag = option->flag,
+            .val = option->val,
+        });
     }
 
-    auto new_argv = const_cast<char**>(m_argv);
-    char* buffer[m_consumed_args];
-    memcpy(buffer, &new_argv[m_arg_index], sizeof(char*) * m_consumed_args);
-    memmove(&new_argv[optind + m_consumed_args], &new_argv[optind], sizeof(char*) * (m_arg_index - optind));
-    memcpy(&new_argv[optind], buffer, sizeof(char*) * m_consumed_args);
-}
-
-bool OptionParser::find_next_option()
-{
-    for (m_arg_index = optind; m_arg_index < m_argc && m_argv[m_arg_index]; m_arg_index++) {
-        StringView arg = current_arg();
-        // Anything that doesn't start with a "-" is not an option.
-        // As a special case, a single "-" is not an option either.
-        // (It's typically used by programs to refer to stdin).
-        if (!arg.starts_with('-') || arg == "-") {
-            if (m_stop_on_first_non_option)
-                return false;
-            continue;
-        }
-
-        // As another special case, a "--" is not an option either, and we stop
-        // looking for further options if we encounter it.
-        if (arg == "--")
-            return false;
-        // Otherwise, we have found an option!
-        return true;
+    if (optind == 0 || optreset == 1) {
+        s_parser.reset_state();
+        optind = 1;
+        optreset = 0;
     }
 
-    // Reached the end and still found no options.
-    return false;
-}
-
-}
-
-int getopt(int argc, char* const* argv, char const* short_options)
-{
-    option dummy { nullptr, 0, nullptr, 0 };
-    OptionParser parser { argc, argv, { short_options, strlen(short_options) }, &dummy };
-    return parser.getopt();
-}
+    auto result = s_parser.getopt(
+        s_args.span(),
+        { short_options, strlen(short_options) },
+        translated_long_options.span(),
+        out_long_option_index ? *out_long_option_index : Optional<int&>());
 
-int getopt_long(int argc, char* const* argv, char const* short_options, const struct option* long_options, int* out_long_option_index)
-{
-    OptionParser parser { argc, argv, { short_options, strlen(short_options) }, long_options, out_long_option_index };
-    return parser.getopt();
+    optind += result.consumed_args;
+    optarg = result.optarg_value.map([](auto x) { return const_cast<char*>(x.characters_without_null_termination()); }).value_or(optarg);
+    optopt = result.optopt_value.value_or(optopt);
+    return result.result;
 }
diff --git a/Userland/Libraries/LibCore/ArgsParser.cpp b/Userland/Libraries/LibCore/ArgsParser.cpp
index a3448921dd..e0a390a86a 100644
--- a/Userland/Libraries/LibCore/ArgsParser.cpp
+++ b/Userland/Libraries/LibCore/ArgsParser.cpp
@@ -7,24 +7,15 @@
 
 #include <AK/Format.h>
 #include <AK/JsonObject.h>
+#include <AK/OptionParser.h>
 #include <AK/StringBuilder.h>
 #include <LibCore/ArgsParser.h>
 #include <LibCore/Version.h>
-#include <getopt.h>
 #include <limits.h>
 #include <math.h>
 #include <stdio.h>
 #include <string.h>
 
-static Optional<double> convert_to_double(char const* s)
-{
-    char* p;
-    double v = strtod(s, &p);
-    if (isnan(v) || p == s)
-        return {};
-    return v;
-}
-
 namespace Core {
 
 ArgsParser::ArgsParser()
@@ -34,16 +25,18 @@ ArgsParser::ArgsParser()
     add_option(m_perform_autocomplete, "Perform autocompletion", "complete", 0, OptionHideMode::CommandLineAndMarkdown);
 }
 
-bool ArgsParser::parse(int argc, char* const* argv, FailureBehavior failure_behavior)
+bool ArgsParser::parse(Span<StringView> arguments, FailureBehavior failure_behavior)
 {
-    auto fail = [this, argv, failure_behavior] {
+    auto fail = [this, name = arguments[0], failure_behavior] {
         if (failure_behavior == FailureBehavior::PrintUsage || failure_behavior == FailureBehavior::PrintUsageAndExit)
-            print_usage(stderr, argv[0]);
+            print_usage(stderr, name);
         if (failure_behavior == FailureBehavior::Exit || failure_behavior == FailureBehavior::PrintUsageAndExit)
             exit(1);
     };
 
-    Vector<option> long_options;
+    OptionParser parser;
+
+    Vector<OptionParser::Option> long_options;
     StringBuilder short_options_builder;
 
     if (m_stop_on_first_non_option)
@@ -51,16 +44,16 @@ bool ArgsParser::parse(int argc, char* const* argv, FailureBehavior failure_beha
 
     int index_of_found_long_option = -1;
 
-    // Tell getopt() to reset its internal state, and start scanning from optind = 1.
-    // We could also set optreset = 1, but the host platform may not support that.
-    optind = 0;
-
     for (size_t i = 0; i < m_options.size(); i++) {
         auto& opt = m_options[i];
         if (opt.long_name) {
-            option long_opt {
-                opt.long_name,
-                opt.argument_mode == OptionArgumentMode::Required ? required_argument : (opt.argument_mode == OptionArgumentMode::Optional ? optional_argument : no_argument),
+            OptionParser::Option long_opt {
+                { opt.long_name, strlen(opt.long_name) },
+                opt.argument_mode == OptionArgumentMode::Required
+                    ? OptionParser::ArgumentRequirement::HasRequiredArgument
+                    : opt.argument_mode == OptionArgumentMode::Optional
+                    ? OptionParser::ArgumentRequirement::HasOptionalArgument
+                    : OptionParser::ArgumentRequirement::NoArgument,
                 &index_of_found_long_option,
                 static_cast<int>(i)
             };
@@ -75,16 +68,20 @@ bool ArgsParser::parse(int argc, char* const* argv, FailureBehavior failure_beha
                 short_options_builder.append(':');
         }
     }
-    long_options.append({ 0, 0, 0, 0 });
 
     auto short_options = short_options_builder.to_deprecated_string();
-
+    size_t option_index = 1;
     while (true) {
-        int c = getopt_long(argc, argv, short_options.characters(), long_options.data(), nullptr);
+        auto result = parser.getopt(arguments.slice(1), short_options, long_options, {});
+        option_index += result.consumed_args;
+
+        auto c = result.result;
         if (c == -1) {
             // We have reached the end.
             break;
-        } else if (c == '?') {
+        }
+
+        if (c == '?') {
             // There was an error, and getopt() has already
             // printed its error message.
             fail();
@@ -106,7 +103,7 @@ bool ArgsParser::parse(int argc, char* const* argv, FailureBehavior failure_beha
         }
         VERIFY(found_option);
 
-        char const* arg = found_option->argument_mode != OptionArgumentMode::None ? optarg : nullptr;
+        StringView arg = found_option->argument_mode != OptionArgumentMode::None ? result.optarg_value.value_or({}) : StringView {};
         if (!found_option->accept_value(arg)) {
             warnln("\033[31mInvalid value for option \033[1m{}\033[22m\033[0m", found_option->name_for_display());
             fail();
@@ -125,14 +122,14 @@ bool ArgsParser::parse(int argc, char* const* argv, FailureBehavior failure_beha
     }
 
     if (m_show_help) {
-        print_usage(stdout, argv[0]);
+        print_usage(stdout, arguments[0]);
         if (failure_behavior == FailureBehavior::Exit || failure_behavior == FailureBehavior::PrintUsageAndExit)
             exit(0);
         return false;
     }
 
     if (m_perform_autocomplete) {
-        autocomplete(stdout, { argv[0], strlen(argv[0]) }, ReadonlySpan<char const*> { argv + optind, static_cast<size_t>(argc - optind) });
+        autocomplete(stdout, arguments[0], arguments.slice(option_index));
         if (failure_behavior == FailureBehavior::Exit || failure_behavior == FailureBehavior::PrintUsageAndExit)
             exit(0);
         return false;
@@ -140,7 +137,7 @@ bool ArgsParser::parse(int argc, char* const* argv, FailureBehavior failure_beha
 
     // Now let's parse positional arguments.
 
-    int values_left = argc - optind;
+    int values_left = arguments.size() - option_index;
     Vector<int, 16> num_values_for_arg;
     num_values_for_arg.resize(m_positional_args.size(), true);
     int total_values_required = 0;
@@ -174,7 +171,7 @@ bool ArgsParser::parse(int argc, char* const* argv, FailureBehavior failure_beha
     for (size_t i = 0; i < m_positional_args.size(); i++) {
         auto& arg = m_positional_args[i];
         for (int j = 0; j < num_values_for_arg[i]; j++) {
-            char const* value = argv[optind++];
+            StringView value = arguments[option_index++];
             if (!arg.accept_value(value)) {
                 warnln("Invalid value for argument {}", arg.name);
                 fail();
@@ -186,7 +183,7 @@ bool ArgsParser::parse(int argc, char* const* argv, FailureBehavior failure_beha
     return true;
 }
 
-void ArgsParser::print_usage(FILE* file, char const* argv0)
+void ArgsParser::print_usage(FILE* file, StringView argv0)
 {
     char const* env_preference = getenv("ARGSPARSER_EMIT_MARKDOWN");
     if (env_preference != nullptr && env_preference[0] == '1' && env_preference[1] == 0) {
@@ -196,7 +193,7 @@ void ArgsParser::print_usage(FILE* file, char const* argv0)
     }
 }
 
-void ArgsParser::print_usage_terminal(FILE* file, char const* argv0)
+void ArgsParser::print_usage_terminal(FILE* file, StringView argv0)
 {
     out(file, "Usage:\n\t\033[1m{}\033[0m", argv0);
 
@@ -272,7 +269,7 @@ void ArgsParser::print_usage_terminal(FILE* file, char const* argv0)
     }
 }
 
-void ArgsParser::print_usage_markdown(FILE* file, char const* argv0)
+void ArgsParser::print_usage_markdown(FILE* file, StringView argv0)
 {
     outln(file, "## Name\n\n{}", argv0);
 
@@ -383,7 +380,7 @@ void ArgsParser::add_ignored(char const* long_name, char short_name, OptionHideM
         long_name,
         short_name,
         nullptr,
-        [](char const*) {
+        [](StringView) {
             return true;
         },
         hide_mode,
@@ -399,8 +396,8 @@ void ArgsParser::add_option(bool& value, char const* help_string, char const* lo
         long_name,
         short_name,
         nullptr,
-        [&value](char const* s) {
-            VERIFY(s == nullptr);
+        [&value](StringView s) {
+            VERIFY(s.is_empty());
             value = true;
             return true;
         },
@@ -417,8 +414,9 @@ void ArgsParser::add_option(char const*& value, char const* help_string, char co
         long_name,
         short_name,
         value_name,
-        [&value](char const* s) {
-            value = s;
+        [&value](StringView s) {
+            VERIFY(s.length() == strlen(s.characters_without_null_termination()));
+            value = s.characters_without_null_termination();
             return true;
         },
         hide_mode,
@@ -434,7 +432,7 @@ void ArgsParser::add_option(DeprecatedString& value, char const* help_string, ch
         long_name,
         short_name,
         value_name,
-        [&value](char const* s) {
+        [&value](StringView s) {
             value = s;
             return true;
         },
@@ -451,8 +449,8 @@ void ArgsParser::add_option(StringView& value, char const* help_string, char con
         long_name,
         short_name,
         value_name,
-        [&value](char const* s) {
-            value = { s, strlen(s) };
+        [&value](StringView s) {
+            value = s;
             return true;
         },
         hide_mode,
@@ -469,8 +467,7 @@ void ArgsParser::add_option(I& value, char const* help_string, char const* long_
         long_name,
         short_name,
         value_name,
-        [&value](char const* s) {
-            auto view = StringView { s, strlen(s) };
+        [&value](StringView view) {
             Optional<I> opt;
             if constexpr (IsSigned<I>)
                 opt = view.to_int<I>();
@@ -499,8 +496,8 @@ void ArgsParser::add_option(double& value, char const* help_string, char const*
         long_name,
         short_name,
         value_name,
-        [&value](char const* s) {
-            auto opt = convert_to_double(s);
+        [&value](StringView s) {
+            auto opt = s.to_double();
             value = opt.value_or(0.0);
             return opt.has_value();
         },
@@ -517,8 +514,8 @@ void ArgsParser::add_option(Optional<double>& value, char const* help_string, ch
         long_name,
         short_name,
         value_name,
-        [&value](char const* s) {
-            value = convert_to_double(s);
+        [&value](StringView s) {
+            value = s.to_double();
             return value.has_value();
         },
         hide_mode,
@@ -534,8 +531,8 @@ void ArgsParser::add_option(Optional<size_t>& value, char const* help_string, ch
         long_name,
         short_name,
         value_name,
-        [&value](char const* s) {
-            value = AK::StringUtils::convert_to_uint<size_t>({ s, strlen(s) });
+        [&value](StringView s) {
+            value = AK::StringUtils::convert_to_uint<size_t>(s);
             return value.has_value();
         },
         hide_mode,
@@ -551,10 +548,10 @@ void ArgsParser::add_option(Vector<size_t>& values, char const* help_string, cha
         long_name,
         short_name,
         value_name,
-        [&values, separator](char const* s) {
+        [&values, separator](StringView s) {
             bool parsed_all_values = true;
 
-            StringView { s, strlen(s) }.for_each_split_view(separator, SplitBehavior::Nothing, [&](auto value) {
+            s.for_each_split_view(separator, SplitBehavior::Nothing, [&](auto value) {
                 if (auto maybe_value = AK::StringUtils::convert_to_uint<size_t>(value); maybe_value.has_value())
                     values.append(*maybe_value);
                 else
@@ -577,9 +574,8 @@ void ArgsParser::add_option(Vector<DeprecatedString>& values, char const* help_s
         long_name,
         short_name,
         value_name,
-        [&values](char const* s) {
-            DeprecatedString value = s;
-            values.append(value);
+        [&values](StringView s) {
+            values.append(s);
             return true;
         },
         hide_mode
@@ -600,8 +596,9 @@ void ArgsParser::add_positional_argument(char const*& value, char const* help_st
         name,
         required == Required::Yes ? 1 : 0,
         1,
-        [&value](char const* s) {
-            value = s;
+        [&value](StringView s) {
+            VERIFY(s.length() == strlen(s.characters_without_null_termination()));
+            value = s.characters_without_null_termination();
             return true;
         }
     };
@@ -615,7 +612,7 @@ void ArgsParser::add_positional_argument(DeprecatedString& value, char const* he
         name,
         required == Required::Yes ? 1 : 0,
         1,
-        [&value](char const* s) {
+        [&value](StringView s) {
             value = s;
             return true;
         }
@@ -630,8 +627,8 @@ void ArgsParser::add_positional_argument(StringView& value, char const* help_str
         name,
         required == Required::Yes ? 1 : 0,
         1,
-        [&value](char const* s) {
-            value = { s, strlen(s) };
+        [&value](StringView s) {
+            value = s;
             return true;
         }
     };
@@ -645,8 +642,8 @@ void ArgsParser::add_positional_argument(int& value, char const* help_string, ch
         name,
         required == Required::Yes ? 1 : 0,
         1,
-        [&value](char const* s) {
-            auto opt = StringView { s, strlen(s) }.to_int();
+        [&value](StringView s) {
+            auto opt = s.to_int();
             value = opt.value_or(0);
             return opt.has_value();
         }
@@ -661,8 +658,8 @@ void ArgsParser::add_positional_argument(unsigned& value, char const* help_strin
         name,
         required == Required::Yes ? 1 : 0,
         1,
-        [&value](char const* s) {
-            auto opt = StringView { s, strlen(s) }.to_uint();
+        [&value](StringView s) {
+            auto opt = s.to_uint();
             value = opt.value_or(0);
             return opt.has_value();
         }
@@ -677,8 +674,8 @@ void ArgsParser::add_positional_argument(double& value, char const* help_string,
         name,
         required == Required::Yes ? 1 : 0,
         1,
-        [&value](char const* s) {
-            auto opt = convert_to_double(s);
+        [&value](StringView s) {
+            auto opt = s.to_double();
             value = opt.value_or(0.0);
             return opt.has_value();
         }
@@ -693,8 +690,9 @@ void ArgsParser::add_positional_argument(Vector<char const*>& values, char const
         name,
         required == Required::Yes ? 1 : 0,
         INT_MAX,
-        [&values](char const* s) {
-            values.append(s);
+        [&values](StringView s) {
+            VERIFY(s.length() == strlen(s.characters_without_null_termination()));
+            values.append(s.characters_without_null_termination());
             return true;
         }
     };
@@ -708,7 +706,7 @@ void ArgsParser::add_positional_argument(Vector<DeprecatedString>& values, char
         name,
         required == Required::Yes ? 1 : 0,
         INT_MAX,
-        [&values](char const* s) {
+        [&values](StringView s) {
             values.append(s);
             return true;
         }
@@ -723,15 +721,15 @@ void ArgsParser::add_positional_argument(Vector<StringView>& values, char const*
         name,
         required == Required::Yes ? 1 : 0,
         INT_MAX,
-        [&values](char const* s) {
-            values.append({ s, strlen(s) });
+        [&values](StringView s) {
+            values.append(s);
             return true;
         }
     };
     add_positional_argument(move(arg));
 }
 
-void ArgsParser::autocomplete(FILE* file, StringView program_name, ReadonlySpan<char const*> remaining_arguments)
+void ArgsParser::autocomplete(FILE* file, StringView program_name, ReadonlySpan<StringView> remaining_arguments)
 {
     // We expect the full invocation of the program to be available as positional args,
     // e.g. `foo --bar arg -b` (program invoked as `foo --complete -- foo --bar arg -b`)
@@ -743,9 +741,7 @@ void ArgsParser::autocomplete(FILE* file, StringView program_name, ReadonlySpan<
     StringView option_to_complete;
     auto completing_option = false;
 
-    for (auto& arg : remaining_arguments) {
-        StringView argument { arg, strlen(arg) };
-
+    for (auto& argument : remaining_arguments) {
         completing_option = false;
         if (skip_next) {
             argument_to_complete = argument;
diff --git a/Userland/Libraries/LibCore/ArgsParser.h b/Userland/Libraries/LibCore/ArgsParser.h
index bfde098f34..93eaf480e0 100644
--- a/Userland/Libraries/LibCore/ArgsParser.h
+++ b/Userland/Libraries/LibCore/ArgsParser.h
@@ -51,7 +51,7 @@ public:
         char const* long_name { nullptr };
         char short_name { 0 };
         char const* value_name { nullptr };
-        Function<bool(char const*)> accept_value;
+        Function<bool(StringView)> accept_value;
         OptionHideMode hide_mode { OptionHideMode::None };
 
         DeprecatedString name_for_display() const
@@ -67,34 +67,21 @@ public:
         char const* name { nullptr };
         int min_values { 0 };
         int max_values { 1 };
-        Function<bool(char const*)> accept_value;
+        Function<bool(StringView)> accept_value;
     };
 
-    bool parse(int argc, char* const* argv, FailureBehavior failure_behavior = FailureBehavior::PrintUsageAndExit);
+    bool parse(Span<StringView> arguments, FailureBehavior failure_behavior = FailureBehavior::PrintUsageAndExit);
     bool parse(Main::Arguments const& arguments, FailureBehavior failure_behavior = FailureBehavior::PrintUsageAndExit)
     {
-        if (arguments.argv == nullptr && arguments.argc == 0) {
-            // Allocate the data from arguments.strings instead.
-            Vector<DeprecatedString> strings;
-            Vector<char const*> data;
-            strings.ensure_capacity(arguments.strings.size());
-            data.ensure_capacity(arguments.strings.size());
-            for (auto& entry : arguments.strings) {
-                strings.append(entry);
-                data.append(strings.last().characters());
-            }
-            return parse(data.size(), const_cast<char* const*>(data.data()), failure_behavior);
-        }
-
-        return parse(arguments.argc, arguments.argv, failure_behavior);
+        return parse(arguments.strings, failure_behavior);
     }
 
     // *Without* trailing newline!
     void set_general_help(char const* help_string) { m_general_help = help_string; };
     void set_stop_on_first_non_option(bool stop_on_first_non_option) { m_stop_on_first_non_option = stop_on_first_non_option; }
-    void print_usage(FILE*, char const* argv0);
-    void print_usage_terminal(FILE*, char const* argv0);
-    void print_usage_markdown(FILE*, char const* argv0);
+    void print_usage(FILE*, StringView argv0);
+    void print_usage_terminal(FILE*, StringView argv0);
+    void print_usage_markdown(FILE*, StringView argv0);
     void print_version(FILE*);
 
     void add_option(Option&&);
@@ -125,7 +112,7 @@ public:
     void add_positional_argument(Vector<StringView>& value, char const* help_string, char const* name, Required required = Required::Yes);
 
 private:
-    void autocomplete(FILE*, StringView program_name, ReadonlySpan<char const*> remaining_arguments);
+    void autocomplete(FILE*, StringView program_name, ReadonlySpan<StringView> remaining_arguments);
 
     Vector<Option> m_options;
     Vector<Arg> m_positional_args;
diff --git a/Userland/Libraries/LibTest/JavaScriptTestRunnerMain.cpp b/Userland/Libraries/LibTest/JavaScriptTestRunnerMain.cpp
index 579c3be5fd..6320fbb5d0 100644
--- a/Userland/Libraries/LibTest/JavaScriptTestRunnerMain.cpp
+++ b/Userland/Libraries/LibTest/JavaScriptTestRunnerMain.cpp
@@ -56,6 +56,11 @@ static void handle_sigabrt(int)
 
 int main(int argc, char** argv)
 {
+    Vector<StringView> arguments;
+    arguments.ensure_capacity(argc);
+    for (auto i = 0; i < argc; ++i)
+        arguments.append({ argv[i], strlen(argv[i]) });
+
     g_test_argc = argc;
     g_test_argv = argv;
     auto program_name = LexicalPath::basename(argv[0]);
@@ -100,7 +105,7 @@ int main(int argc, char** argv)
         .help_string = "Show progress with OSC 9 (true, false)",
         .long_name = "show-progress",
         .short_name = 'p',
-        .accept_value = [&](auto* str) {
+        .accept_value = [&](StringView str) {
             if ("true"sv == str)
                 print_progress = true;
             else if ("false"sv == str)
@@ -120,7 +125,7 @@ int main(int argc, char** argv)
         args_parser.add_option(*entry.key, entry.value.get<0>().characters(), entry.value.get<1>().characters(), entry.value.get<2>());
     args_parser.add_positional_argument(specified_test_root, "Tests root directory", "path", Core::ArgsParser::Required::No);
     args_parser.add_positional_argument(common_path, "Path to tests-common.js", "common-path", Core::ArgsParser::Required::No);
-    args_parser.parse(argc, argv);
+    args_parser.parse(arguments);
 
     if (per_file)
         print_json = true;
diff --git a/Userland/Libraries/LibTest/TestMain.cpp b/Userland/Libraries/LibTest/TestMain.cpp
index 6a232e1618..c39e64cb6b 100644
--- a/Userland/Libraries/LibTest/TestMain.cpp
+++ b/Userland/Libraries/LibTest/TestMain.cpp
@@ -22,7 +22,13 @@ int TEST_MAIN(int argc, char** argv)
         warnln("Test main does not have a valid test name!");
         return 1;
     }
-    int ret = ::Test::TestSuite::the().main(argv[0], argc, argv);
+
+    Vector<StringView> arguments;
+    arguments.ensure_capacity(argc);
+    for (auto i = 0; i < argc; ++i)
+        arguments.append({ argv[i], strlen(argv[i]) });
+
+    int ret = ::Test::TestSuite::the().main(argv[0], arguments);
     ::Test::TestSuite::release();
     return ret;
 }
diff --git a/Userland/Libraries/LibTest/TestSuite.cpp b/Userland/Libraries/LibTest/TestSuite.cpp
index 14c2312248..0c2238681a 100644
--- a/Userland/Libraries/LibTest/TestSuite.cpp
+++ b/Userland/Libraries/LibTest/TestSuite.cpp
@@ -56,7 +56,7 @@ void set_suite_setup_function(Function<void()> setup)
     TestSuite::the().set_suite_setup(move(setup));
 }
 
-int TestSuite::main(DeprecatedString const& suite_name, int argc, char** argv)
+int TestSuite::main(DeprecatedString const& suite_name, Span<StringView> arguments)
 {
     m_suite_name = suite_name;
 
@@ -71,7 +71,7 @@ int TestSuite::main(DeprecatedString const& suite_name, int argc, char** argv)
     args_parser.add_option(do_benchmarks_only, "Only run benchmarks.", "bench", 0);
     args_parser.add_option(do_list_cases, "List available test cases.", "list", 0);
     args_parser.add_positional_argument(search_string, "Only run matching cases.", "pattern", Core::ArgsParser::Required::No);
-    args_parser.parse(argc, argv);
+    args_parser.parse(arguments);
 
     if (m_setup)
         m_setup();
diff --git a/Userland/Libraries/LibTest/TestSuite.h b/Userland/Libraries/LibTest/TestSuite.h
index 827e78d031..2b286f336b 100644
--- a/Userland/Libraries/LibTest/TestSuite.h
+++ b/Userland/Libraries/LibTest/TestSuite.h
@@ -33,7 +33,7 @@ public:
     }
 
     int run(NonnullRefPtrVector<TestCase> const&);
-    int main(DeprecatedString const& suite_name, int argc, char** argv);
+    int main(DeprecatedString const& suite_name, Span<StringView> arguments);
     NonnullRefPtrVector<TestCase> find_cases(DeprecatedString const& search, bool find_tests, bool find_benchmarks);
     void add_case(NonnullRefPtr<TestCase> const& test_case)
     {