/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil; -*- */
// SPDX-License-Identifier: MIT OR LGPL-2.0-or-later
// SPDX-FileCopyrightText: 2008 litl, LLC
// SPDX-FileCopyrightText: 2020 Canonical, Ltd.

#include <config.h>

#include <stdint.h>
#include <string.h>  // for strcmp, strlen, memcpy

#include <string>

#include <girepository.h>
#include <glib-object.h>
#include <glib.h>

#include <js/Array.h>
#include <js/CharacterEncoding.h>
#include <js/Conversions.h>
#include <js/GCVector.h>            // for RootedVector, MutableWrappedPtrOp...
#include <js/PropertyDescriptor.h>  // for JSPROP_ENUMERATE
#include <js/RootingAPI.h>
#include <js/TypeDecls.h>
#include <js/Utility.h>  // for UniqueChars
#include <js/Value.h>
#include <js/ValueArray.h>
#include <jsapi.h>        // for JS_ReportOutOfMemory, JS_GetElement
#include <jsfriendapi.h>  // for JS_IsUint8Array, JS_GetObjectFunc...

#include "gi/arg-inl.h"
#include "gi/arg-types-inl.h"
#include "gi/arg.h"
#include "gi/boxed.h"
#include "gi/foreign.h"
#include "gi/fundamental.h"
#include "gi/gerror.h"
#include "gi/gtype.h"
#include "gi/interface.h"
#include "gi/js-value-inl.h"
#include "gi/object.h"
#include "gi/param.h"
#include "gi/union.h"
#include "gi/value.h"
#include "gi/wrapperutils.h"
#include "gjs/atoms.h"
#include "gjs/byteArray.h"
#include "gjs/context-private.h"
#include "gjs/enum-utils.h"
#include "gjs/jsapi-util.h"
#include "util/log.h"

GJS_JSAPI_RETURN_CONVENTION static bool gjs_g_arg_release_internal(
    JSContext* cx, GITransfer transfer, GITypeInfo* type_info,
    GITypeTag type_tag, GArgument* arg);
static void throw_invalid_argument(JSContext* cx, JS::HandleValue value,
                                   GITypeInfo* arginfo, const char* arg_name,
                                   GjsArgumentType arg_type);

bool _gjs_flags_value_is_valid(JSContext* context, GType gtype, int64_t value) {
    GFlagsValue *v;
    guint32 tmpval;

    /* FIXME: Do proper value check for flags with GType's */
    if (gtype == G_TYPE_NONE)
        return true;

    GjsAutoTypeClass<GTypeClass> klass(gtype);

    /* check all bits are defined for flags.. not necessarily desired */
    tmpval = (guint32)value;
    if (tmpval != value) { /* Not a guint32 */
        gjs_throw(context,
                  "0x%" G_GINT64_MODIFIER "x is not a valid value for flags %s",
                  value, g_type_name(G_TYPE_FROM_CLASS(klass)));
        return false;
    }

    while (tmpval) {
        v = g_flags_get_first_value(klass.as<GFlagsClass>(), tmpval);
        if (!v) {
            gjs_throw(context,
                      "0x%x is not a valid value for flags %s",
                      (guint32)value, g_type_name(G_TYPE_FROM_CLASS(klass)));
            return false;
        }

        tmpval &= ~v->value;
    }

    return true;
}

GJS_JSAPI_RETURN_CONVENTION
static bool _gjs_enum_value_is_valid(JSContext* context, GIEnumInfo* enum_info,
                                     int64_t value) {
    bool found;
    int n_values;
    int i;

    n_values = g_enum_info_get_n_values(enum_info);
    found = false;

    for (i = 0; i < n_values; ++i) {
        GjsAutoValueInfo value_info = g_enum_info_get_value(enum_info, i);
        int64_t enum_value = g_value_info_get_value(value_info);

        if (enum_value == value) {
            found = true;
            break;
        }
    }

    if (!found) {
        gjs_throw(context,
                  "%" G_GINT64_MODIFIER "d is not a valid value for enumeration %s",
                  value, g_base_info_get_name((GIBaseInfo *)enum_info));
    }

    return found;
}

[[nodiscard]] static bool _gjs_enum_uses_signed_type(GIEnumInfo* enum_info) {
    switch (g_enum_info_get_storage_type(enum_info)) {
        case GI_TYPE_TAG_INT8:
        case GI_TYPE_TAG_INT16:
        case GI_TYPE_TAG_INT32:
        case GI_TYPE_TAG_INT64:
            return true;
        default:
            return false;
    }
}

// This is hacky - g_function_info_invoke() and g_field_info_get/set_field()
// expect the enum value in gjs_arg_member<int>(arg) and depend on all flags and
// enumerations being passed on the stack in a 32-bit field. See FIXME comment
// in g_field_info_get_field(). The same assumption of enums cast to 32-bit
// signed integers is found in g_value_set_enum()/g_value_set_flags().
[[nodiscard]] int64_t _gjs_enum_from_int(GIEnumInfo* enum_info, int int_value) {
    if (_gjs_enum_uses_signed_type (enum_info))
        return int64_t(int_value);
    else
        return int64_t(uint32_t(int_value));
}

/* Here for symmetry, but result is the same for the two cases */
[[nodiscard]] static int _gjs_enum_to_int(int64_t value) {
    return static_cast<int>(value);
}

/* Check if an argument of the given needs to be released if we created it
 * from a JS value to pass it into a function and aren't transferring ownership.
 */
[[nodiscard]] static bool type_needs_release(GITypeInfo* type_info,
                                             GITypeTag type_tag) {
    switch (type_tag) {
        case GI_TYPE_TAG_ARRAY:
        case GI_TYPE_TAG_ERROR:
        case GI_TYPE_TAG_FILENAME:
        case GI_TYPE_TAG_GHASH:
        case GI_TYPE_TAG_GLIST:
        case GI_TYPE_TAG_GSLIST:
        case GI_TYPE_TAG_UTF8:
            return true;

        case GI_TYPE_TAG_INTERFACE: {
            GType gtype;

            GjsAutoBaseInfo interface_info =
                g_type_info_get_interface(type_info);
            g_assert(interface_info != nullptr);

            switch (g_base_info_get_type(interface_info)) {
                case GI_INFO_TYPE_STRUCT:
                case GI_INFO_TYPE_ENUM:
                case GI_INFO_TYPE_FLAGS:
                case GI_INFO_TYPE_OBJECT:
                case GI_INFO_TYPE_INTERFACE:
                case GI_INFO_TYPE_UNION:
                case GI_INFO_TYPE_BOXED:
                    // These are subtypes of GIRegisteredTypeInfo for which the
                    // cast is safe
                    gtype = g_registered_type_info_get_g_type(interface_info);
                    break;
                case GI_INFO_TYPE_VALUE:
                    // Special case for GValues
                    gtype = G_TYPE_VALUE;
                    break;
                default:
                    gtype = G_TYPE_NONE;
            }

            if (g_type_is_a(gtype, G_TYPE_CLOSURE))
                return true;
            else if (g_type_is_a(gtype, G_TYPE_VALUE))
                return g_type_info_is_pointer(type_info);
            else
                return false;
        }

        default:
            return false;
    }
}

/* Check if an argument of the given needs to be released if we obtained it
 * from out argument (or the return value), and we're transferring ownership
 */
[[nodiscard]] static bool type_needs_out_release(GITypeInfo* type_info,
                                                 GITypeTag type_tag) {
    switch (type_tag) {
        case GI_TYPE_TAG_ARRAY:
        case GI_TYPE_TAG_ERROR:
        case GI_TYPE_TAG_FILENAME:
        case GI_TYPE_TAG_GHASH:
        case GI_TYPE_TAG_GLIST:
        case GI_TYPE_TAG_GSLIST:
        case GI_TYPE_TAG_UTF8:
            return true;

        case GI_TYPE_TAG_INTERFACE: {
            GjsAutoBaseInfo interface_info =
                g_type_info_get_interface(type_info);

            switch (g_base_info_get_type(interface_info)) {
                case GI_INFO_TYPE_ENUM:
                case GI_INFO_TYPE_FLAGS:
                    return false;

                case GI_INFO_TYPE_STRUCT:
                case GI_INFO_TYPE_UNION:
                    return g_type_info_is_pointer(type_info);

                default:
                    return false;
            }
        }

        default:
            return false;
    }
}

template <typename T>
GJS_JSAPI_RETURN_CONVENTION static bool gjs_array_to_g_list(
    JSContext* cx, const JS::HandleValue& value, GITypeInfo* type_info,
    GITransfer transfer, const char* arg_name, GjsArgumentType arg_type,
    T** list_p) {
    static_assert(std::is_same_v<T, GList> || std::is_same_v<T, GSList>);

    // While a list can be NULL in C, that means empty array in JavaScript, it
    // doesn't mean null in JavaScript.
    if (!value.isObject())
        return false;

    bool found_length;
    const GjsAtoms& atoms = GjsContextPrivate::atoms(cx);
    JS::RootedObject array_obj(cx, &value.toObject());

    if (!JS_HasPropertyById(cx, array_obj, atoms.length(), &found_length)) {
        throw_invalid_argument(cx, value, type_info, arg_name, arg_type);
        return false;
    }

    if (!found_length) {
        throw_invalid_argument(cx, value, type_info, arg_name, arg_type);
        return false;
    }

    uint32_t length;
    if (!gjs_object_require_converted_property(cx, array_obj, nullptr,
                                               atoms.length(), &length)) {
        throw_invalid_argument(cx, value, type_info, arg_name, arg_type);
        return false;
    }

    GjsAutoTypeInfo param_info = g_type_info_get_param_type(type_info, 0);
    g_assert(param_info);

    if (transfer == GI_TRANSFER_CONTAINER) {
        if (type_needs_release (param_info, g_type_info_get_tag(param_info))) {
            /* FIXME: to make this work, we'd have to keep a list of temporary
             * GArguments for the function call so we could free them after
             * the surrounding container had been freed by the callee.
             */
            gjs_throw(cx, "Container transfer for in parameters not supported");
            return false;
        }

        transfer = GI_TRANSFER_NOTHING;
    }

    JS::RootedObject array(cx, value.toObjectOrNull());
    JS::RootedValue elem(cx);
    T* list = nullptr;

    for (size_t i = 0; i < length; ++i) {
        GArgument elem_arg = { 0 };

        elem = JS::UndefinedValue();
        if (!JS_GetElement(cx, array, i, &elem)) {
            gjs_throw(cx, "Missing array element %zu", i);
            return false;
        }

        /* FIXME we don't know if the list elements can be NULL.
         * gobject-introspection needs to tell us this.
         * Always say they can't for now.
         */
        if (!gjs_value_to_g_argument(cx, elem, param_info,
                                     GJS_ARGUMENT_LIST_ELEMENT, transfer,
                                     &elem_arg)) {
            return false;
        }

        void* hash_pointer =
            g_type_info_hash_pointer_from_argument(param_info, &elem_arg);

        if constexpr (std::is_same_v<T, GList>)
            list = g_list_prepend(list, hash_pointer);
        else if constexpr (std::is_same_v<T, GSList>)
            list = g_slist_prepend(list, hash_pointer);
    }

    if constexpr (std::is_same_v<T, GList>)
        list = g_list_reverse(list);
    else if constexpr (std::is_same_v<T, GSList>)
        list = g_slist_reverse(list);

    *list_p = list;

    return true;
}

[[nodiscard]] static GHashTable* create_hash_table_for_key_type(
    GITypeInfo* key_param_info) {
    /* Don't use key/value destructor functions here, because we can't
     * construct correct ones in general if the value type is complex.
     * Rely on the type-aware g_argument_release functions. */

    GITypeTag key_type = g_type_info_get_tag(key_param_info);

    if (key_type == GI_TYPE_TAG_UTF8 || key_type == GI_TYPE_TAG_FILENAME)
        return g_hash_table_new(g_str_hash, g_str_equal);
    return g_hash_table_new(NULL, NULL);
}

template <typename IntType>
GJS_JSAPI_RETURN_CONVENTION static bool hashtable_int_key(
    JSContext* cx, const JS::HandleValue& value, void** pointer_out) {
    static_assert(std::is_integral_v<IntType>, "Need an integer");
    bool out_of_range = false;

    Gjs::JsValueHolder::Strict<IntType> i;
    if (!Gjs::js_value_to_c_checked<IntType>(cx, value, &i, &out_of_range))
        return false;

    if (out_of_range) {
        gjs_throw(cx, "value is out of range for hash table key of type %s",
                  Gjs::static_type_name<IntType>());
    }

    *pointer_out = gjs_int_to_pointer<IntType>(i);

    return true;
}

/* Converts a JS::Value to a GHashTable key, stuffing it into @pointer_out if
 * possible, otherwise giving the location of an allocated key in @pointer_out.
 */
GJS_JSAPI_RETURN_CONVENTION
static bool
value_to_ghashtable_key(JSContext      *cx,
                        JS::HandleValue value,
                        GITypeInfo     *type_info,
                        gpointer       *pointer_out)
{
    GITypeTag type_tag = g_type_info_get_tag((GITypeInfo*) type_info);
    bool unsupported = false;

    g_return_val_if_fail(value.isString() || value.isInt32(), false);

    gjs_debug_marshal(GJS_DEBUG_GFUNCTION,
                      "Converting JS::Value to GHashTable key %s",
                      g_type_tag_to_string(type_tag));

    switch (type_tag) {
    case GI_TYPE_TAG_BOOLEAN:
        /* This doesn't seem particularly useful, but it's easy */
        *pointer_out = gjs_int_to_pointer(JS::ToBoolean(value));
        break;

    case GI_TYPE_TAG_UNICHAR:
        if (value.isInt32()) {
            *pointer_out = gjs_int_to_pointer(value.toInt32());
        } else {
            uint32_t ch;
            if (!gjs_unichar_from_string(cx, value, &ch))
                return false;
            *pointer_out = gjs_int_to_pointer(ch);
        }
        break;

    case GI_TYPE_TAG_INT8:
        if (!hashtable_int_key<int8_t>(cx, value, pointer_out))
            return false;
        break;

    case GI_TYPE_TAG_INT16:
        if (!hashtable_int_key<int16_t>(cx, value, pointer_out))
            return false;
        break;

    case GI_TYPE_TAG_INT32:
        if (!hashtable_int_key<int32_t>(cx, value, pointer_out))
            return false;
        break;

    case GI_TYPE_TAG_UINT8:
        if (!hashtable_int_key<uint8_t>(cx, value, pointer_out))
            return false;
        break;

    case GI_TYPE_TAG_UINT16:
        if (!hashtable_int_key<uint16_t>(cx, value, pointer_out))
            return false;
        break;

    case GI_TYPE_TAG_UINT32:
        if (!hashtable_int_key<uint32_t>(cx, value, pointer_out))
            return false;
        break;

    case GI_TYPE_TAG_FILENAME: {
        GjsAutoChar cstr;
        JS::RootedValue str_val(cx, value);
        if (!str_val.isString()) {
            JS::RootedString str(cx, JS::ToString(cx, str_val));
            str_val.setString(str);
        }
        if (!gjs_string_to_filename(cx, str_val, &cstr))
            return false;
        *pointer_out = cstr.release();
        break;
    }

    case GI_TYPE_TAG_UTF8: {
        JS::RootedString str(cx);
        if (!value.isString())
            str = JS::ToString(cx, value);
        else
            str = value.toString();

        JS::UniqueChars cstr(JS_EncodeStringToUTF8(cx, str));
        if (!cstr)
            return false;
        *pointer_out = g_strdup(cstr.get());
        break;
    }

    case GI_TYPE_TAG_FLOAT:
    case GI_TYPE_TAG_DOUBLE:
    case GI_TYPE_TAG_INT64:
    case GI_TYPE_TAG_UINT64:
    /* FIXME: The above four could be supported, but are currently not. The ones
     * below cannot be key types in a regular JS object; we would need to allow
     * marshalling Map objects into GHashTables to support those. */
    case GI_TYPE_TAG_VOID:
    case GI_TYPE_TAG_GTYPE:
    case GI_TYPE_TAG_ERROR:
    case GI_TYPE_TAG_INTERFACE:
    case GI_TYPE_TAG_GLIST:
    case GI_TYPE_TAG_GSLIST:
    case GI_TYPE_TAG_GHASH:
    case GI_TYPE_TAG_ARRAY:
        unsupported = true;
        break;

    default:
        g_warning("Unhandled type %s for GHashTable key conversion",
                  g_type_tag_to_string(type_tag));
        unsupported = true;
        break;
    }

    if (G_UNLIKELY(unsupported)) {
        gjs_throw(cx, "Type %s not supported for hash table keys",
                  g_type_tag_to_string(type_tag));
        return false;
    }

    return true;
}

template <typename T>
[[nodiscard]] static T* heap_value_new_from_arg(GIArgument* val_arg) {
    T* heap_val = g_new(T, 1);
    *heap_val = gjs_arg_get<T>(val_arg);

    return heap_val;
}

GJS_JSAPI_RETURN_CONVENTION
static bool gjs_object_to_g_hash(JSContext* context, JS::HandleObject props,
                                 GITypeInfo* key_param_info,
                                 GITypeInfo* val_param_info,
                                 GITransfer transfer, GHashTable** hash_p) {
    size_t id_ix, id_len;

    g_assert(props && "Property bag cannot be null");

    if (transfer == GI_TRANSFER_CONTAINER) {
        if (type_needs_release (key_param_info, g_type_info_get_tag(key_param_info)) ||
            type_needs_release (val_param_info, g_type_info_get_tag(val_param_info))) {
            /* FIXME: to make this work, we'd have to keep a list of temporary
             * GArguments for the function call so we could free them after
             * the surrounding container had been freed by the callee.
             */
            gjs_throw(context,
                      "Container transfer for in parameters not supported");
            return false;
        }

        transfer = GI_TRANSFER_NOTHING;
    }

    JS::Rooted<JS::IdVector> ids(context, context);
    if (!JS_Enumerate(context, props, &ids))
        return false;

    GjsAutoPointer<GHashTable, GHashTable, g_hash_table_destroy> result =
        create_hash_table_for_key_type(key_param_info);

    JS::RootedValue key_js(context), val_js(context);
    JS::RootedId cur_id(context);
    for (id_ix = 0, id_len = ids.length(); id_ix < id_len; ++id_ix) {
        cur_id = ids[id_ix];
        gpointer key_ptr, val_ptr;
        GIArgument val_arg = { 0 };

        if (!JS_IdToValue(context, cur_id, &key_js) ||
            // Type check key type.
            !value_to_ghashtable_key(context, key_js, key_param_info,
                                     &key_ptr) ||
            !JS_GetPropertyById(context, props, cur_id, &val_js) ||
            // Type check and convert value to a C type
            !gjs_value_to_g_argument(context, val_js, val_param_info, nullptr,
                                     GJS_ARGUMENT_HASH_ELEMENT, transfer,
                                     GjsArgumentFlags::MAY_BE_NULL, &val_arg))
            return false;

        GITypeTag val_type = g_type_info_get_tag(val_param_info);
        /* Use heap-allocated values for types that don't fit in a pointer */
        if (val_type == GI_TYPE_TAG_INT64) {
            val_ptr = heap_value_new_from_arg<int64_t>(&val_arg);
        } else if (val_type == GI_TYPE_TAG_UINT64) {
            val_ptr = heap_value_new_from_arg<uint64_t>(&val_arg);
        } else if (val_type == GI_TYPE_TAG_FLOAT) {
            val_ptr = heap_value_new_from_arg<float>(&val_arg);
        } else if (val_type == GI_TYPE_TAG_DOUBLE) {
            val_ptr = heap_value_new_from_arg<double>(&val_arg);
        } else {
            // Other types are simply stuffed inside the pointer
            val_ptr = g_type_info_hash_pointer_from_argument(val_param_info,
                                                             &val_arg);
        }

#if __GNUC__ >= 8  // clang-format off
_Pragma("GCC diagnostic push")
_Pragma("GCC diagnostic ignored \"-Wmaybe-uninitialized\"")
#endif
        // The compiler isn't smart enough to figure out that key_ptr will
        // always be initialized if value_to_ghashtable_key() returns true.
        g_hash_table_insert(result, key_ptr, val_ptr);
#if __GNUC__ >= 8
_Pragma("GCC diagnostic pop")
#endif  // clang-format on
    }

    *hash_p = result.release();
    return true;
}

template <typename T>
[[nodiscard]] constexpr T* array_allocate(size_t length) {
    if constexpr (std::is_same_v<T, char*>)
        return g_new0(char*, length);

    T* array = g_new(T, length);
    array[length - 1] = {0};
    return array;
}

template <GITypeTag TAG, typename T>
GJS_JSAPI_RETURN_CONVENTION static bool js_value_to_c_strict(
    JSContext* cx, const JS::HandleValue& value, T* out) {
    using ValueHolderT = Gjs::JsValueHolder::Strict<T, TAG>;
    if constexpr (Gjs::type_has_js_getter<T, ValueHolderT>())
        return Gjs::js_value_to_c<TAG>(cx, value, out);

    ValueHolderT v;
    bool ret = Gjs::js_value_to_c<TAG>(cx, value, &v);
    *out = v;

    return ret;
}

template <typename T, GITypeTag TAG = GI_TYPE_TAG_VOID>
GJS_JSAPI_RETURN_CONVENTION static bool gjs_array_to_auto_array(
    JSContext* cx, JS::Value array_value, size_t length, void** arr_p) {
    JS::RootedObject array(cx, array_value.toObjectOrNull());
    JS::RootedValue elem(cx);

    // Add one so we're always zero terminated
    GjsSmartPointer<T> result = array_allocate<T>(length + 1);

    for (size_t i = 0; i < length; ++i) {
        elem = JS::UndefinedValue();

        if (!JS_GetElement(cx, array, i, &elem)) {
            gjs_throw(cx, "Missing array element %" G_GSIZE_FORMAT, i);
            return false;
        }

        if (!js_value_to_c_strict<TAG>(cx, elem, &result[i])) {
            gjs_throw(cx, "Invalid element in %s array",
                      Gjs::static_type_name<T, TAG>());
            return false;
        }
    }

    *arr_p = result.release();

    return true;
}

bool
gjs_array_from_strv(JSContext             *context,
                    JS::MutableHandleValue value_p,
                    const char           **strv)
{
    guint i;
    JS::RootedValueVector elems(context);

    /* We treat a NULL strv as an empty array, since this function should always
     * set an array value when returning true.
     * Another alternative would be to set value_p to JS::NullValue, but clients
     * would need to always check for both an empty array and null if that was
     * the case.
     */
    for (i = 0; strv != NULL && strv[i] != NULL; i++) {
        if (!elems.growBy(1)) {
            JS_ReportOutOfMemory(context);
            return false;
        }

        if (!gjs_string_from_utf8(context, strv[i], elems[i]))
            return false;
    }

    JS::RootedObject obj(context, JS::NewArrayObject(context, elems));
    if (!obj)
        return false;

    value_p.setObject(*obj);

    return true;
}

bool
gjs_array_to_strv(JSContext   *context,
                  JS::Value    array_value,
                  unsigned int length,
                  void       **arr_p)
{
    return gjs_array_to_auto_array<char*>(context, array_value, length, arr_p);
}

GJS_JSAPI_RETURN_CONVENTION
static bool
gjs_string_to_intarray(JSContext       *context,
                       JS::HandleString str,
                       GITypeInfo      *param_info,
                       void           **arr_p,
                       size_t          *length)
{
    GITypeTag element_type;
    char16_t *result16;

    element_type = g_type_info_get_tag(param_info);

    switch (element_type) {
        case GI_TYPE_TAG_INT8:
        case GI_TYPE_TAG_UINT8: {
            JS::UniqueChars result(JS_EncodeStringToUTF8(context, str));
            if (!result)
                return false;
            *length = strlen(result.get());
            *arr_p = g_strdup(result.get());
            return true;
        }

        case GI_TYPE_TAG_INT16:
        case GI_TYPE_TAG_UINT16: {
            if (!gjs_string_get_char16_data(context, str, &result16, length))
                return false;
            *arr_p = result16;
            return true;
        }

        case GI_TYPE_TAG_UNICHAR: {
            gunichar* result_ucs4;
            if (!gjs_string_to_ucs4(context, str, &result_ucs4, length))
                return false;
            *arr_p = result_ucs4;
            return true;
        }

        default:
            /* can't convert a string to this type */
            gjs_throw(context, "Cannot convert string to array of '%s'",
                      g_type_tag_to_string(element_type));
            return false;
    }
}

GJS_JSAPI_RETURN_CONVENTION
static bool
gjs_array_to_ptrarray(JSContext   *context,
                      JS::Value    array_value,
                      unsigned int length,
                      GITransfer   transfer,
                      GITypeInfo  *param_info,
                      void       **arr_p)
{
    unsigned int i;
    JS::RootedObject array_obj(context, array_value.toObjectOrNull());
    JS::RootedValue elem(context);

    /* Always one extra element, to cater for null terminated arrays */
    GjsAutoPointer<void*> array = array_allocate<void*>(length + 1);

    for (i = 0; i < length; i++) {
        GIArgument arg;
        gjs_arg_unset<void*>(&arg);

        elem = JS::UndefinedValue();
        if (!JS_GetElement(context, array_obj, i, &elem)) {
            gjs_throw(context,
                      "Missing array element %u",
                      i);
            return false;
        }

        if (!gjs_value_to_g_argument(
                context, elem, param_info,
                GJS_ARGUMENT_ARRAY_ELEMENT, transfer,
                &arg)) {
            gjs_throw(context,
                      "Invalid element in array");
            return false;
        }

        array[i] = gjs_arg_get<void*>(&arg);
    }

    *arr_p = array.release();
    return true;
}

GJS_JSAPI_RETURN_CONVENTION
static bool gjs_array_to_flat_struct_array(JSContext* cx,
                                           JS::HandleValue array_value,
                                           unsigned length,
                                           GITypeInfo* param_info,
                                           GIBaseInfo* interface_info,
                                           GIInfoType info_type, void** arr_p) {
    g_assert(
        (info_type == GI_INFO_TYPE_STRUCT || info_type == GI_INFO_TYPE_UNION) &&
        "Only flat arrays of unboxed structs or unions are supported");
    size_t struct_size;
    if (info_type == GI_INFO_TYPE_UNION)
        struct_size = g_union_info_get_size(interface_info);
    else
        struct_size = g_struct_info_get_size(interface_info);

    GjsAutoPointer<uint8_t> flat_array = g_new0(uint8_t, struct_size * length);

    JS::RootedObject array(cx, &array_value.toObject());
    JS::RootedValue elem(cx);
    for (unsigned i = 0; i < length; i++) {
        elem = JS::UndefinedValue();

        if (!JS_GetElement(cx, array, i, &elem)) {
            gjs_throw(cx, "Missing array element %u", i);
            return false;
        }

        GIArgument arg;
        if (!gjs_value_to_g_argument(cx, elem, param_info,
                                     GJS_ARGUMENT_ARRAY_ELEMENT,
                                     GI_TRANSFER_NOTHING, &arg))
            return false;

        memcpy(&flat_array[struct_size * i], gjs_arg_get<void*>(&arg),
               struct_size);
    }

    *arr_p = flat_array.release();
    return true;
}

GJS_JSAPI_RETURN_CONVENTION
static bool
gjs_array_from_flat_gvalue_array(JSContext             *context,
                                 gpointer               array,
                                 unsigned               length,
                                 JS::MutableHandleValue value)
{
    GValue *values = (GValue *)array;

    // a null array pointer takes precedence over whatever `length` says
    if (!values) {
        JSObject* jsarray = JS::NewArrayObject(context, 0);
        if (!jsarray)
            return false;
        value.setObject(*jsarray);
        return true;
    }

    unsigned int i;
    JS::RootedValueVector elems(context);
    if (!elems.resize(length)) {
        JS_ReportOutOfMemory(context);
        return false;
    }

    bool result = true;

    for (i = 0; i < length; i ++) {
        GValue *gvalue = &values[i];
        result = gjs_value_from_g_value(context, elems[i], gvalue);
        if (!result)
            break;
    }

    if (result) {
        JSObject *jsarray;
        jsarray = JS::NewArrayObject(context, elems);
        value.setObjectOrNull(jsarray);
    }

    return result;
}

[[nodiscard]] static bool is_gvalue(GIBaseInfo* info, GIInfoType info_type) {
    switch (info_type) {
        case GI_INFO_TYPE_VALUE:
            return true;

        case GI_INFO_TYPE_STRUCT:
        case GI_INFO_TYPE_OBJECT:
        case GI_INFO_TYPE_INTERFACE:
        case GI_INFO_TYPE_BOXED: {
            GType gtype = g_registered_type_info_get_g_type(info);
            return g_type_is_a(gtype, G_TYPE_VALUE);
        }

        default:
            return false;
    }
}

[[nodiscard]] static bool is_gvalue_flat_array(GITypeInfo* param_info,
                                               GITypeTag element_type) {
    GIInfoType info_type;

    if (element_type != GI_TYPE_TAG_INTERFACE)
        return false;

    GjsAutoBaseInfo interface_info = g_type_info_get_interface(param_info);
    info_type = g_base_info_get_type(interface_info);

    /* Special case for GValue "flat arrays" */
    return (is_gvalue(interface_info, info_type) &&
            !g_type_info_is_pointer(param_info));
}

GJS_JSAPI_RETURN_CONVENTION
static bool gjs_array_to_array(JSContext* context, JS::HandleValue array_value,
                               size_t length, GITransfer transfer,
                               GITypeInfo* param_info, void** arr_p) {
    GITypeTag element_type = g_type_info_get_storage_type(param_info);

    /* Special case for GValue "flat arrays" */
    if (is_gvalue_flat_array(param_info, element_type))
        return gjs_array_to_auto_array<GValue>(context, array_value, length,
                                               arr_p);

    switch (element_type) {
    case GI_TYPE_TAG_UTF8:
        return gjs_array_to_strv (context, array_value, length, arr_p);
    case GI_TYPE_TAG_BOOLEAN:
        return gjs_array_to_auto_array<gboolean, GI_TYPE_TAG_BOOLEAN>(
            context, array_value, length, arr_p);
    case GI_TYPE_TAG_UNICHAR:
        return gjs_array_to_auto_array<char32_t>(context, array_value, length,
                                                 arr_p);
    case GI_TYPE_TAG_UINT8:
        return gjs_array_to_auto_array<uint8_t>(context, array_value, length,
                                                arr_p);
    case GI_TYPE_TAG_INT8:
        return gjs_array_to_auto_array<int8_t>(context, array_value, length,
                                               arr_p);
    case GI_TYPE_TAG_UINT16:
        return gjs_array_to_auto_array<uint16_t>(context, array_value, length,
                                                 arr_p);
    case GI_TYPE_TAG_INT16:
        return gjs_array_to_auto_array<int16_t>(context, array_value, length,
                                                arr_p);
    case GI_TYPE_TAG_UINT32:
        return gjs_array_to_auto_array<uint32_t>(context, array_value, length,
                                                 arr_p);
    case GI_TYPE_TAG_INT32:
        return gjs_array_to_auto_array<int32_t>(context, array_value, length,
                                                arr_p);
    case GI_TYPE_TAG_INT64:
        return gjs_array_to_auto_array<int64_t>(context, array_value, length,
                                                arr_p);
    case GI_TYPE_TAG_UINT64:
        return gjs_array_to_auto_array<uint64_t>(context, array_value, length,
                                                 arr_p);
    case GI_TYPE_TAG_FLOAT:
        return gjs_array_to_auto_array<float>(context, array_value, length,
                                              arr_p);
    case GI_TYPE_TAG_DOUBLE:
        return gjs_array_to_auto_array<double>(context, array_value, length,
                                               arr_p);
    case GI_TYPE_TAG_GTYPE:
        return gjs_array_to_auto_array<GType, GI_TYPE_TAG_GTYPE>(
            context, array_value, length, arr_p);

    /* Everything else is a pointer type */
    case GI_TYPE_TAG_INTERFACE:
        if (!g_type_info_is_pointer(param_info)) {
            GjsAutoBaseInfo interface_info =
                g_type_info_get_interface(param_info);
            GIInfoType info_type = g_base_info_get_type(interface_info);
            if (info_type == GI_INFO_TYPE_STRUCT ||
                info_type == GI_INFO_TYPE_UNION) {
                // Ignore transfer in the case of a flat struct array. Structs
                // are copied by value.
                return gjs_array_to_flat_struct_array(
                    context, array_value, length, param_info, interface_info,
                    info_type, arr_p);
            }
        }
        [[fallthrough]];
    case GI_TYPE_TAG_ARRAY:
    case GI_TYPE_TAG_GLIST:
    case GI_TYPE_TAG_GSLIST:
    case GI_TYPE_TAG_GHASH:
    case GI_TYPE_TAG_ERROR:
    case GI_TYPE_TAG_FILENAME:
        return gjs_array_to_ptrarray(context,
                                     array_value,
                                     length,
                                     transfer == GI_TRANSFER_CONTAINER ? GI_TRANSFER_NOTHING : transfer,
                                     param_info,
                                     arr_p);
    case GI_TYPE_TAG_VOID:
    default:
        gjs_throw(context,
                  "Unhandled array element type %d", element_type);
        return false;
    }
}

GJS_JSAPI_RETURN_CONVENTION
static GArray*
gjs_g_array_new_for_type(JSContext    *context,
                         unsigned int  length,
                         GITypeInfo   *param_info)
{
    guint element_size;
    GITypeTag element_type = g_type_info_get_storage_type(param_info);

    switch (element_type) {
    case GI_TYPE_TAG_BOOLEAN:
        element_size = sizeof(gboolean);
        break;
    case GI_TYPE_TAG_UNICHAR:
        element_size = sizeof(char32_t);
        break;
    case GI_TYPE_TAG_UINT8:
    case GI_TYPE_TAG_INT8:
        element_size = sizeof(uint8_t);
        break;
    case GI_TYPE_TAG_UINT16:
    case GI_TYPE_TAG_INT16:
        element_size = sizeof(uint16_t);
        break;
    case GI_TYPE_TAG_UINT32:
    case GI_TYPE_TAG_INT32:
        element_size = sizeof(uint32_t);
        break;
    case GI_TYPE_TAG_UINT64:
    case GI_TYPE_TAG_INT64:
        element_size = sizeof(uint64_t);
        break;
    case GI_TYPE_TAG_FLOAT:
        element_size = sizeof(float);
        break;
    case GI_TYPE_TAG_DOUBLE:
        element_size = sizeof(double);
        break;
    case GI_TYPE_TAG_GTYPE:
      element_size = sizeof(GType);
      break;
    case GI_TYPE_TAG_INTERFACE:
    case GI_TYPE_TAG_UTF8:
    case GI_TYPE_TAG_FILENAME:
    case GI_TYPE_TAG_ARRAY:
    case GI_TYPE_TAG_GLIST:
    case GI_TYPE_TAG_GSLIST:
    case GI_TYPE_TAG_GHASH:
    case GI_TYPE_TAG_ERROR:
        element_size = sizeof(void*);
        break;
    case GI_TYPE_TAG_VOID:
    default:
        gjs_throw(context,
                  "Unhandled GArray element-type %d", element_type);
        return NULL;
    }

    return g_array_sized_new(true, false, element_size, length);
}

char* gjs_argument_display_name(const char* arg_name,
                                GjsArgumentType arg_type) {
    switch (arg_type) {
    case GJS_ARGUMENT_ARGUMENT:
        return g_strdup_printf("Argument '%s'", arg_name);
    case GJS_ARGUMENT_RETURN_VALUE:
        return g_strdup("Return value");
    case GJS_ARGUMENT_FIELD:
        return g_strdup_printf("Field '%s'", arg_name);
    case GJS_ARGUMENT_LIST_ELEMENT:
        return g_strdup("List element");
    case GJS_ARGUMENT_HASH_ELEMENT:
        return g_strdup("Hash element");
    case GJS_ARGUMENT_ARRAY_ELEMENT:
        return g_strdup("Array element");
    default:
        g_assert_not_reached ();
    }
}

[[nodiscard]] static const char* type_tag_to_human_string(
    GITypeInfo* type_info) {
    GITypeTag tag;

    tag = g_type_info_get_tag(type_info);

    if (tag == GI_TYPE_TAG_INTERFACE) {
        GjsAutoBaseInfo interface = g_type_info_get_interface(type_info);
        return g_info_type_to_string(g_base_info_get_type(interface));
    } else {
        return g_type_tag_to_string(tag);
    }
}

static void
throw_invalid_argument(JSContext      *context,
                       JS::HandleValue value,
                       GITypeInfo     *arginfo,
                       const char     *arg_name,
                       GjsArgumentType arg_type)
{
    GjsAutoChar display_name = gjs_argument_display_name(arg_name, arg_type);

    gjs_throw(context, "Expected type %s for %s but got type '%s'",
              type_tag_to_human_string(arginfo), display_name.get(),
              JS::InformalValueTypeName(value));
}

GJS_JSAPI_RETURN_CONVENTION
bool gjs_array_to_explicit_array(JSContext* context, JS::HandleValue value,
                                 GITypeInfo* type_info, const char* arg_name,
                                 GjsArgumentType arg_type, GITransfer transfer,
                                 GjsArgumentFlags flags, void** contents,
                                 size_t* length_p) {
    bool found_length;

    gjs_debug_marshal(
        GJS_DEBUG_GFUNCTION,
        "Converting argument '%s' JS value %s to C array, transfer %d",
        arg_name, gjs_debug_value(value).c_str(), transfer);

    GjsAutoTypeInfo param_info = g_type_info_get_param_type(type_info, 0);

    if ((value.isNull() && !(flags & GjsArgumentFlags::MAY_BE_NULL)) ||
        (!value.isString() && !value.isObjectOrNull())) {
        throw_invalid_argument(context, value, param_info, arg_name, arg_type);
        return false;
    }

    if (value.isNull()) {
        *contents = NULL;
        *length_p = 0;
    } else if (value.isString()) {
        /* Allow strings as int8/uint8/int16/uint16 arrays */
        JS::RootedString str(context, value.toString());
        if (!gjs_string_to_intarray(context, str, param_info, contents, length_p))
            return false;
    } else {
        JS::RootedObject array_obj(context, &value.toObject());
        const GjsAtoms& atoms = GjsContextPrivate::atoms(context);
        GITypeTag element_type = g_type_info_get_tag(param_info);
        if (JS_IsUint8Array(array_obj) && (element_type == GI_TYPE_TAG_INT8 ||
                                           element_type == GI_TYPE_TAG_UINT8)) {
            GBytes* bytes = gjs_byte_array_get_bytes(array_obj);
            *contents = g_bytes_unref_to_data(bytes, length_p);
        } else if (JS_HasPropertyById(context, array_obj, atoms.length(),
                                      &found_length) &&
                   found_length) {
            guint32 length;

            if (!gjs_object_require_converted_property(
                    context, array_obj, nullptr, atoms.length(), &length)) {
                return false;
            } else {
                if (!gjs_array_to_array(context,
                                        value,
                                        length,
                                        transfer,
                                        param_info,
                                        contents))
                    return false;

                *length_p = length;
            }
        } else {
            throw_invalid_argument(context, value, param_info, arg_name, arg_type);
            return false;
        }
    }

    return true;
}

[[nodiscard]] static bool is_gdk_atom(GIBaseInfo* info) {
    return (strcmp("Atom", g_base_info_get_name(info)) == 0 &&
            strcmp("Gdk", g_base_info_get_namespace(info)) == 0);
}

static void
intern_gdk_atom(const char *name,
                GArgument  *ret)
{
    GjsAutoFunctionInfo atom_intern_fun =
        g_irepository_find_by_name(nullptr, "Gdk", "atom_intern");

    GIArgument atom_intern_args[2];

    /* Can only store char * in GIArgument. First argument to gdk_atom_intern
     * is const char *, string isn't modified. */
    gjs_arg_set(&atom_intern_args[0], name);
    gjs_arg_set(&atom_intern_args[1], false);

    g_function_info_invoke(atom_intern_fun,
                           atom_intern_args, 2,
                           nullptr, 0,
                           ret,
                           nullptr);
}

static bool value_to_interface_gi_argument(
    JSContext* cx, JS::HandleValue value, GIBaseInfo* interface_info,
    GIInfoType interface_type, GITransfer transfer, bool expect_object,
    GIArgument* arg, GjsArgumentType arg_type, GjsArgumentFlags flags,
    bool* report_type_mismatch) {
    g_assert(report_type_mismatch);
    GType gtype;

    switch (interface_type) {
        case GI_INFO_TYPE_BOXED:
        case GI_INFO_TYPE_ENUM:
        case GI_INFO_TYPE_FLAGS:
        case GI_INFO_TYPE_INTERFACE:
        case GI_INFO_TYPE_OBJECT:
        case GI_INFO_TYPE_STRUCT:
        case GI_INFO_TYPE_UNION:
            // These are subtypes of GIRegisteredTypeInfo for which the cast is
            // safe
            gtype = g_registered_type_info_get_g_type(interface_info);
            break;

        case GI_INFO_TYPE_VALUE:
            // Special case for GValues
            gtype = G_TYPE_VALUE;
            break;

        default:
            gtype = G_TYPE_NONE;
    }

    if (gtype != G_TYPE_NONE)
        gjs_debug_marshal(GJS_DEBUG_GFUNCTION, "gtype of INTERFACE is %s",
                          g_type_name(gtype));

    if (gtype == G_TYPE_VALUE) {
        if (flags & GjsArgumentFlags::CALLER_ALLOCATES) {
            if (!gjs_value_to_g_value_no_copy(cx, value,
                                              gjs_arg_get<GValue*>(arg)))
                return false;

            return true;
        }

        GValue gvalue = G_VALUE_INIT;
        if (!gjs_value_to_g_value(cx, value, &gvalue)) {
            gjs_arg_unset<void*>(arg);
            return false;
        }

        gjs_arg_set(arg, g_boxed_copy(G_TYPE_VALUE, &gvalue));
        g_value_unset(&gvalue);
        return true;

    } else if (is_gdk_atom(interface_info)) {
        if (!value.isNull() && !value.isString()) {
            *report_type_mismatch = true;
            return false;
        } else if (value.isNull()) {
            intern_gdk_atom("NONE", arg);
            return true;
        }

        JS::RootedString str(cx, value.toString());
        JS::UniqueChars name(JS_EncodeStringToUTF8(cx, str));
        if (!name)
            return false;

        intern_gdk_atom(name.get(), arg);
        return true;

    } else if (expect_object != value.isObjectOrNull()) {
        *report_type_mismatch = true;
        return false;

    } else if (value.isNull()) {
        gjs_arg_set(arg, nullptr);
        return true;

    } else if (value.isObject()) {
        JS::RootedObject obj(cx, &value.toObject());
        if (interface_type == GI_INFO_TYPE_STRUCT &&
            g_struct_info_is_gtype_struct(interface_info)) {
            GType actual_gtype;
            if (!gjs_gtype_get_actual_gtype(cx, obj, &actual_gtype))
                return false;

            if (actual_gtype == G_TYPE_NONE) {
                *report_type_mismatch = true;
                return false;
            }

            // We use peek here to simplify reference counting (we just ignore
            // transfer annotation, as GType classes are never really freed)
            // We know that the GType class is referenced at least once when
            // the JS constructor is initialized.
            void* klass;
            if (g_type_is_a(actual_gtype, G_TYPE_INTERFACE))
                klass = g_type_default_interface_peek(actual_gtype);
            else
                klass = g_type_class_peek(actual_gtype);

            gjs_arg_set(arg, klass);
            return true;

        } else if ((interface_type == GI_INFO_TYPE_STRUCT ||
                    interface_type == GI_INFO_TYPE_BOXED) &&
                   !g_type_is_a(gtype, G_TYPE_CLOSURE)) {
            // Handle Struct/Union first since we don't necessarily need a GType
            // for them. We special case Closures later, so skip them here.
            if (g_type_is_a(gtype, G_TYPE_BYTES) && JS_IsUint8Array(obj)) {
                gjs_arg_set(arg, gjs_byte_array_get_bytes(obj));
                return true;
            }
            if (g_type_is_a(gtype, G_TYPE_ERROR)) {
                return ErrorBase::transfer_to_gi_argument(
                    cx, obj, arg, GI_DIRECTION_IN, transfer);
            }
            return BoxedBase::transfer_to_gi_argument(
                cx, obj, arg, GI_DIRECTION_IN, transfer, gtype, interface_info);

        } else if (interface_type == GI_INFO_TYPE_UNION) {
            return UnionBase::transfer_to_gi_argument(
                cx, obj, arg, GI_DIRECTION_IN, transfer, gtype, interface_info);

        } else if (gtype != G_TYPE_NONE) {
            if (g_type_is_a(gtype, G_TYPE_OBJECT)) {
                return ObjectBase::transfer_to_gi_argument(
                    cx, obj, arg, GI_DIRECTION_IN, transfer, gtype);

            } else if (g_type_is_a(gtype, G_TYPE_PARAM)) {
                if (!gjs_typecheck_param(cx, obj, gtype, true)) {
                    gjs_arg_unset<void*>(arg);
                    return false;
                }
                gjs_arg_set(arg, gjs_g_param_from_param(cx, obj));
                if (transfer != GI_TRANSFER_NOTHING)
                    g_param_spec_ref(gjs_arg_get<GParamSpec*>(arg));
                return true;

            } else if (g_type_is_a(gtype, G_TYPE_BOXED)) {
                if (g_type_is_a(gtype, G_TYPE_CLOSURE)) {
                    GClosure* closure = gjs_closure_new_marshaled(
                        cx, JS_GetObjectFunction(obj), "boxed");
                    // GI doesn't know about floating GClosure references. We
                    // guess that if this is a return value going from JS::Value
                    // to GArgument, it's intended to be passed to a C API that
                    // will consume the floating reference.
                    if (arg_type != GJS_ARGUMENT_RETURN_VALUE) {
                        g_closure_ref(closure);
                        g_closure_sink(closure);
                    }
                    gjs_arg_set(arg, closure);
                    return true;
                }

                // Should have been caught above as STRUCT/BOXED/UNION
                gjs_throw(
                    cx,
                    "Boxed type %s registered for unexpected interface_type %d",
                    g_type_name(gtype), interface_type);
                return false;

            } else if (G_TYPE_IS_INSTANTIATABLE(gtype)) {
                return FundamentalBase::transfer_to_gi_argument(
                    cx, obj, arg, GI_DIRECTION_IN, transfer, gtype);

            } else if (G_TYPE_IS_INTERFACE(gtype)) {
                // Could be a GObject interface that's missing a prerequisite,
                // or could be a fundamental
                if (ObjectBase::typecheck(cx, obj, nullptr, gtype,
                                          GjsTypecheckNoThrow())) {
                    return ObjectBase::transfer_to_gi_argument(
                        cx, obj, arg, GI_DIRECTION_IN, transfer, gtype);
                }

                // If this typecheck fails, then it's neither an object nor a
                // fundamental
                return FundamentalBase::transfer_to_gi_argument(
                    cx, obj, arg, GI_DIRECTION_IN, transfer, gtype);
            }

            gjs_throw(cx, "Unhandled GType %s unpacking GIArgument from Object",
                      g_type_name(gtype));
            gjs_arg_unset<void*>(arg);
            return false;
        }

        gjs_debug(GJS_DEBUG_GFUNCTION,
                  "conversion of JSObject value %s to type %s failed",
                  gjs_debug_value(value).c_str(),
                  g_base_info_get_name(interface_info));

        gjs_throw(cx,
                  "Unexpected unregistered type unpacking GIArgument from "
                  "Object");
        return false;

    } else if (value.isNumber()) {
        if (interface_type == GI_INFO_TYPE_ENUM) {
            int64_t value_int64;

            if (!JS::ToInt64(cx, value, &value_int64) ||
                !_gjs_enum_value_is_valid(cx, interface_info, value_int64))
                return false;

            gjs_arg_set<int, GI_TYPE_TAG_INTERFACE>(
                arg, _gjs_enum_to_int(value_int64));
            return true;

        } else if (interface_type == GI_INFO_TYPE_FLAGS) {
            int64_t value_int64;

            if (!JS::ToInt64(cx, value, &value_int64) ||
                !_gjs_flags_value_is_valid(cx, gtype, value_int64))
                return false;

            gjs_arg_set<int, GI_TYPE_TAG_INTERFACE>(
                arg, _gjs_enum_to_int(value_int64));
            return true;

        } else if (gtype == G_TYPE_NONE) {
            gjs_throw(cx,
                      "Unexpected unregistered type unpacking GIArgument from "
                      "Number");
            return false;
        }

        gjs_throw(cx, "Unhandled GType %s unpacking GIArgument from Number",
                  g_type_name(gtype));
        return false;
    }

    gjs_debug(GJS_DEBUG_GFUNCTION,
              "JSObject type '%s' is neither null nor an object",
              JS::InformalValueTypeName(value));
    *report_type_mismatch = true;
    return false;
}

template <typename T>
GJS_JSAPI_RETURN_CONVENTION inline static bool gjs_arg_set_from_js_value(
    JSContext* cx, const JS::HandleValue& value, GArgument* arg,
    const char* arg_name, GjsArgumentType arg_type) {
    bool out_of_range = false;

    if (!gjs_arg_set_from_js_value<T>(cx, value, arg, &out_of_range)) {
        if (out_of_range) {
            GjsAutoChar display_name =
                gjs_argument_display_name(arg_name, arg_type);
            gjs_throw(cx, "value %s is out of range for %s (type %s)",
                      std::to_string(gjs_arg_get<T>(arg)).c_str(),
                      display_name.get(), Gjs::static_type_name<T>());
        }

        return false;
    }

    gjs_debug_marshal(
        GJS_DEBUG_GFUNCTION, "%s set to value %s (type %s)",
        GjsAutoChar(gjs_argument_display_name(arg_name, arg_type)).get(),
        std::to_string(gjs_arg_get<T>(arg)).c_str(),
        Gjs::static_type_name<T>());

    return true;
}

static bool check_nullable_argument(JSContext* cx, const char* arg_name,
                                    GjsArgumentType arg_type,
                                    GITypeTag type_tag, GjsArgumentFlags flags,
                                    GIArgument* arg) {
    if (!(flags & GjsArgumentFlags::MAY_BE_NULL) && !gjs_arg_get<void*>(arg)) {
        GjsAutoChar display_name =
            gjs_argument_display_name(arg_name, arg_type);
        gjs_throw(cx, "%s (type %s) may not be null", display_name.get(),
                  g_type_tag_to_string(type_tag));
        return false;
    }

    return true;
}

bool gjs_value_to_g_argument(JSContext* context, JS::HandleValue value,
                             GITypeInfo* type_info, const char* arg_name,
                             GjsArgumentType arg_type, GITransfer transfer,
                             GjsArgumentFlags flags, GIArgument* arg) {
    GITypeTag type_tag = g_type_info_get_tag(type_info);

    gjs_debug_marshal(
        GJS_DEBUG_GFUNCTION,
        "Converting argument '%s' JS value %s to GIArgument type %s", arg_name,
        gjs_debug_value(value).c_str(), g_type_tag_to_string(type_tag));

    switch (type_tag) {
    case GI_TYPE_TAG_VOID:
        // just so it isn't uninitialized
        gjs_arg_unset<void*>(arg);
        return check_nullable_argument(context, arg_name, arg_type, type_tag,
                                       flags, arg);

    case GI_TYPE_TAG_INT8:
        return gjs_arg_set_from_js_value<int8_t>(context, value, arg, arg_name,
                                                 arg_type);
    case GI_TYPE_TAG_UINT8:
        return gjs_arg_set_from_js_value<uint8_t>(context, value, arg, arg_name,
                                                  arg_type);
    case GI_TYPE_TAG_INT16:
        return gjs_arg_set_from_js_value<int16_t>(context, value, arg, arg_name,
                                                  arg_type);

    case GI_TYPE_TAG_UINT16:
        return gjs_arg_set_from_js_value<uint16_t>(context, value, arg,
                                                   arg_name, arg_type);

    case GI_TYPE_TAG_INT32:
        return gjs_arg_set_from_js_value<int32_t>(context, value, arg, arg_name,
                                                  arg_type);

    case GI_TYPE_TAG_UINT32:
        return gjs_arg_set_from_js_value<uint32_t>(context, value, arg,
                                                   arg_name, arg_type);

    case GI_TYPE_TAG_INT64:
        return gjs_arg_set_from_js_value<int64_t>(context, value, arg, arg_name,
                                                  arg_type);

    case GI_TYPE_TAG_UINT64:
        return gjs_arg_set_from_js_value<uint64_t>(context, value, arg,
                                                   arg_name, arg_type);

    case GI_TYPE_TAG_BOOLEAN:
        gjs_arg_set(arg, JS::ToBoolean(value));
        return true;

    case GI_TYPE_TAG_FLOAT:
        return gjs_arg_set_from_js_value<float>(context, value, arg, arg_name,
                                                arg_type);

    case GI_TYPE_TAG_DOUBLE:
        return gjs_arg_set_from_js_value<double>(context, value, arg, arg_name,
                                                 arg_type);

    case GI_TYPE_TAG_UNICHAR:
        if (value.isString()) {
            if (!gjs_unichar_from_string(context, value,
                                         &gjs_arg_member<char32_t>(arg)))
                return false;
        } else {
            throw_invalid_argument(context, value, type_info, arg_name,
                                   arg_type);
            return false;
        }
        break;

    case GI_TYPE_TAG_GTYPE:
        if (value.isObjectOrNull()) {
            GType gtype;
            JS::RootedObject obj(context, value.toObjectOrNull());
            if (!gjs_gtype_get_actual_gtype(context, obj, &gtype))
                return false;

            if (gtype == G_TYPE_INVALID)
                return false;
            gjs_arg_set<GType, GI_TYPE_TAG_GTYPE>(arg, gtype);
        } else {
            throw_invalid_argument(context, value, type_info, arg_name,
                                   arg_type);
            return false;
        }
        break;

    case GI_TYPE_TAG_FILENAME:
        if (value.isNull()) {
            gjs_arg_set(arg, nullptr);
        } else if (value.isString()) {
            GjsAutoChar filename_str;
            if (!gjs_string_to_filename(context, value, &filename_str))
                return false;

            gjs_arg_set(arg, filename_str.release());
        } else {
            throw_invalid_argument(context, value, type_info, arg_name,
                                   arg_type);
            return false;
        }

        return check_nullable_argument(context, arg_name, arg_type, type_tag,
                                       flags, arg);

    case GI_TYPE_TAG_UTF8:
        if (value.isNull()) {
            gjs_arg_set(arg, nullptr);
        } else if (value.isString()) {
            JS::RootedString str(context, value.toString());
            JS::UniqueChars utf8_str(JS_EncodeStringToUTF8(context, str));
            if (!utf8_str)
                return false;

            gjs_arg_set(arg, g_strdup(utf8_str.get()));
        } else {
            throw_invalid_argument(context, value, type_info, arg_name,
                                   arg_type);
            return false;
        }

        return check_nullable_argument(context, arg_name, arg_type, type_tag,
                                       flags, arg);

    case GI_TYPE_TAG_ERROR:
        if (value.isNull()) {
            gjs_arg_set(arg, nullptr);
        } else if (value.isObject()) {
            JS::RootedObject obj(context, &value.toObject());
            if (!ErrorBase::transfer_to_gi_argument(context, obj, arg,
                                                    GI_DIRECTION_IN, transfer))
                return false;
        } else {
            throw_invalid_argument(context, value, type_info, arg_name,
                                   arg_type);
            return false;
        }

        return check_nullable_argument(context, arg_name, arg_type, type_tag,
                                       flags, arg);

    case GI_TYPE_TAG_INTERFACE:
        {
        bool expect_object = true;

        GjsAutoBaseInfo interface_info = g_type_info_get_interface(type_info);
        g_assert(interface_info);

        GIInfoType interface_type = g_base_info_get_type(interface_info);
        if (interface_type == GI_INFO_TYPE_ENUM ||
            interface_type == GI_INFO_TYPE_FLAGS)
            expect_object = false;

        if (interface_type == GI_INFO_TYPE_STRUCT &&
            g_struct_info_is_foreign(interface_info)) {
            return gjs_struct_foreign_convert_to_g_argument(
                context, value, interface_info, arg_name, arg_type, transfer,
                flags, arg);
        }

        bool report_type_mismatch = false;
        if (!value_to_interface_gi_argument(
                context, value, interface_info, interface_type, transfer,
                expect_object, arg, arg_type, flags, &report_type_mismatch)) {
            if (report_type_mismatch)
                throw_invalid_argument(context, value, type_info, arg_name,
                                       arg_type);

            return false;
        }

        if (expect_object)
            return check_nullable_argument(context, arg_name, arg_type,
                                           type_tag, flags, arg);
        }
        break;

    case GI_TYPE_TAG_GLIST:
        return gjs_array_to_g_list(context, value, type_info, transfer,
                                   arg_name, arg_type,
                                   &gjs_arg_member<GList*>(arg));
    case GI_TYPE_TAG_GSLIST:
        return gjs_array_to_g_list(context, value, type_info, transfer,
                                   arg_name, arg_type,
                                   &gjs_arg_member<GSList*>(arg));

    case GI_TYPE_TAG_GHASH:
        if (value.isNull()) {
            gjs_arg_set(arg, nullptr);
            if (!(flags & GjsArgumentFlags::MAY_BE_NULL)) {
                throw_invalid_argument(context, value, type_info, arg_name,
                                       arg_type);
                return false;
            }
        } else if (!value.isObject()) {
            throw_invalid_argument(context, value, type_info, arg_name,
                                   arg_type);
            return false;
        } else {
            GHashTable *ghash;
            GjsAutoTypeInfo key_param_info =
                g_type_info_get_param_type(type_info, 0);
            GjsAutoTypeInfo val_param_info =
                g_type_info_get_param_type(type_info, 1);

            g_assert(key_param_info != nullptr);
            g_assert(val_param_info != nullptr);

            JS::RootedObject props(context, &value.toObject());
            if (!gjs_object_to_g_hash(context, props, key_param_info,
                                      val_param_info, transfer, &ghash)) {
                return false;
            }

            gjs_arg_set(arg, ghash);
        }
        break;

    case GI_TYPE_TAG_ARRAY: {
        GjsAutoPointer<void> data;
        gsize length;
        GIArrayType array_type = g_type_info_get_array_type(type_info);

        /* First, let's handle the case where we're passed an instance
         * of Uint8Array and it needs to be marshalled to GByteArray.
         */
        if (value.isObject()) {
            JSObject* bytearray_obj = &value.toObject();
            if (JS_IsUint8Array(bytearray_obj) &&
                array_type == GI_ARRAY_TYPE_BYTE_ARRAY) {
                gjs_arg_set(arg, gjs_byte_array_get_byte_array(bytearray_obj));
                break;
            } else {
                /* Fall through, !handled */
            }
        }

        if (!gjs_array_to_explicit_array(context, value, type_info, arg_name,
                                         arg_type, transfer, flags, data.out(),
                                         &length)) {
            return false;
        }

        GjsAutoTypeInfo param_info = g_type_info_get_param_type(type_info, 0);
        if (array_type == GI_ARRAY_TYPE_C) {
            gjs_arg_set(arg, data.release());
        } else if (array_type == GI_ARRAY_TYPE_ARRAY) {
            GArray *array = gjs_g_array_new_for_type(context, length, param_info);

            if (!array)
                return false;

            if (data)
                g_array_append_vals(array, data, length);
            gjs_arg_set(arg, array);
        } else if (array_type == GI_ARRAY_TYPE_BYTE_ARRAY) {
            GByteArray *byte_array = g_byte_array_sized_new(length);

            if (data)
                g_byte_array_append(byte_array, data.as<const uint8_t>(),
                                    length);
            gjs_arg_set(arg, byte_array);
        } else if (array_type == GI_ARRAY_TYPE_PTR_ARRAY) {
            GPtrArray *array = g_ptr_array_sized_new(length);

            g_ptr_array_set_size(array, length);
            if (data)
                memcpy(array->pdata, data, sizeof(void*) * length);
            gjs_arg_set(arg, array);
        }
        break;
    }
    default:
        g_warning("Unhandled type %s for JavaScript to GArgument conversion",
                  g_type_tag_to_string(type_tag));
        throw_invalid_argument(context, value, type_info, arg_name, arg_type);
        return false;
    }

    return true;
}

/* If a callback function with a return value throws, we still have
 * to return something to C. This function defines what that something
 * is. It basically boils down to memset(arg, 0, sizeof(*arg)), but
 * gives as a bit more future flexibility and also will work if
 * libffi passes us a buffer that only has room for the appropriate
 * branch of GArgument. (Currently it appears that the return buffer
 * has a fixed size large enough for the union of all types.)
 */
void gjs_gi_argument_init_default(GITypeInfo* type_info, GIArgument* arg) {
    GITypeTag type_tag;

    type_tag = g_type_info_get_tag( (GITypeInfo*) type_info);

    switch (type_tag) {
        case GI_TYPE_TAG_VOID:
            // just so it isn't uninitialized
            gjs_arg_unset<void*>(arg);
            break;
        case GI_TYPE_TAG_INT8:
            gjs_arg_unset<int8_t>(arg);
            break;
        case GI_TYPE_TAG_UINT8:
            gjs_arg_unset<uint8_t>(arg);
            break;
        case GI_TYPE_TAG_INT16:
            gjs_arg_unset<int16_t>(arg);
            break;
        case GI_TYPE_TAG_UINT16:
            gjs_arg_unset<uint16_t>(arg);
            break;
        case GI_TYPE_TAG_INT32:
            gjs_arg_unset<int32_t>(arg);
            break;
        case GI_TYPE_TAG_UINT32:
            gjs_arg_unset<uint32_t>(arg);
            break;
        case GI_TYPE_TAG_UNICHAR:
            gjs_arg_unset<char32_t>(arg);
            break;
        case GI_TYPE_TAG_INT64:
            gjs_arg_unset<int64_t>(arg);
            break;
        case GI_TYPE_TAG_UINT64:
            gjs_arg_unset<uint64_t>(arg);
            break;
        case GI_TYPE_TAG_BOOLEAN:
            gjs_arg_unset<bool>(arg);
            break;
        case GI_TYPE_TAG_FLOAT:
            gjs_arg_unset<float>(arg);
            break;
        case GI_TYPE_TAG_DOUBLE:
            gjs_arg_unset<double>(arg);
            break;
        case GI_TYPE_TAG_GTYPE:
            gjs_arg_unset<GType, GI_TYPE_TAG_GTYPE>(arg);
            break;
        case GI_TYPE_TAG_FILENAME:
        case GI_TYPE_TAG_UTF8:
        case GI_TYPE_TAG_GLIST:
        case GI_TYPE_TAG_GSLIST:
        case GI_TYPE_TAG_ERROR:
            gjs_arg_unset<void*>(arg);
            break;
        case GI_TYPE_TAG_INTERFACE: {
            GIInfoType interface_type;

            GjsAutoBaseInfo interface_info =
                g_type_info_get_interface(type_info);
            g_assert(interface_info != nullptr);

            interface_type = g_base_info_get_type(interface_info);

            if (interface_type == GI_INFO_TYPE_ENUM ||
                interface_type == GI_INFO_TYPE_FLAGS)
                gjs_arg_unset<int, GI_TYPE_TAG_INTERFACE>(arg);
            else
                gjs_arg_unset<void*>(arg);
        } break;
        case GI_TYPE_TAG_GHASH:
            // Possibly better to return an empty hash table?
            gjs_arg_unset<GHashTable*>(arg);
            break;
        case GI_TYPE_TAG_ARRAY:
            gjs_arg_unset<void*>(arg);
            break;
        default:
            g_warning("Unhandled type %s for default GArgument initialization",
                      g_type_tag_to_string(type_tag));
            break;
    }
}

bool gjs_value_to_callback_out_arg(JSContext* context, JS::HandleValue value,
                                   GIArgInfo* arg_info, GIArgument* arg) {
    GIDirection direction [[maybe_unused]] = g_arg_info_get_direction(arg_info);
    g_assert(
        (direction == GI_DIRECTION_OUT || direction == GI_DIRECTION_INOUT) &&
        "gjs_value_to_callback_out_arg does not handle in arguments.");

    GjsArgumentFlags flags = GjsArgumentFlags::NONE;
    GITypeInfo type_info;

    g_arg_info_load_type(arg_info, &type_info);

    // If the argument is optional and we're passed nullptr,
    // ignore the GJS value.
    if (g_arg_info_is_optional(arg_info) && !arg)
        return true;

    // Otherwise, throw an error to prevent a segfault.
    if (!arg) {
        gjs_throw(context,
                  "Return value %s is not optional but was passed NULL",
                  g_base_info_get_name(arg_info));
        return false;
    }

    if (g_arg_info_may_be_null(arg_info))
        flags |= GjsArgumentFlags::MAY_BE_NULL;
    if (g_arg_info_is_caller_allocates(arg_info))
        flags |= GjsArgumentFlags::CALLER_ALLOCATES;

    return gjs_value_to_g_argument(
        context, value, &type_info, g_base_info_get_name(arg_info),
        (g_arg_info_is_return_value(arg_info) ? GJS_ARGUMENT_RETURN_VALUE
                                              : GJS_ARGUMENT_ARGUMENT),
        g_arg_info_get_ownership_transfer(arg_info), flags, arg);
}

template <typename T>
GJS_JSAPI_RETURN_CONVENTION static bool gjs_array_from_g_list(
    JSContext* cx, JS::MutableHandleValue value_p, GITypeInfo* type_info,
    T* list) {
    static_assert(std::is_same_v<T, GList> || std::is_same_v<T, GSList>);
    GArgument arg;
    JS::RootedValueVector elems(cx);
    GjsAutoTypeInfo param_info = g_type_info_get_param_type(type_info, 0);

    g_assert(param_info);

    for (size_t i = 0; list; list = list->next, ++i) {
        g_type_info_argument_from_hash_pointer(param_info, list->data, &arg);

        if (!elems.growBy(1)) {
            JS_ReportOutOfMemory(cx);
            return false;
        }

        if (!gjs_value_from_g_argument(cx, elems[i], param_info, &arg, true))
            return false;
    }

    JS::RootedObject obj(cx, JS::NewArrayObject(cx, elems));
    if (!obj)
        return false;

    value_p.setObject(*obj);

    return true;
}

template <typename T>
GJS_JSAPI_RETURN_CONVENTION static bool gjs_g_arg_release_g_list(
    JSContext* cx, GITransfer transfer, GITypeInfo* type_info,
    GIArgument* arg) {
    static_assert(std::is_same_v<T, GList> || std::is_same_v<T, GSList>);
    GjsSmartPointer<T> list = gjs_arg_steal<T*>(arg);

    if (transfer == GI_TRANSFER_CONTAINER)
        return true;

    GIArgument elem;
    GjsAutoTypeInfo param_info = g_type_info_get_param_type(type_info, 0);
    g_assert(param_info);
    GITypeTag type_tag = g_type_info_get_tag(param_info);

    for (T* l = list; l; l = l->next) {
        gjs_arg_set(&elem, l->data);

        if (!gjs_g_arg_release_internal(cx, transfer, param_info, type_tag,
                                        &elem)) {
            return false;
        }
    }

    return true;
}

template <typename T, GITypeTag TAG = GI_TYPE_TAG_VOID>
GJS_JSAPI_RETURN_CONVENTION static bool fill_vector_from_carray(
    JSContext* cx, JS::RootedValueVector& elems,  // NOLINT(runtime/references)
    GITypeInfo* param_info, GIArgument* arg, void* array, size_t length) {
    for (size_t i = 0; i < length; i++) {
        gjs_arg_set<T, TAG>(arg, *(static_cast<T*>(array) + i));

        if (!gjs_value_from_g_argument(cx, elems[i], param_info, arg, true))
            return false;
    }

    return true;
}

GJS_JSAPI_RETURN_CONVENTION
static bool
gjs_array_from_carray_internal (JSContext             *context,
                                JS::MutableHandleValue value_p,
                                GIArrayType            array_type,
                                GITypeInfo            *param_info,
                                guint                  length,
                                gpointer               array)
{
    GArgument arg;
    GITypeTag element_type;
    guint i;

    element_type = g_type_info_get_tag(param_info);

    if (is_gvalue_flat_array(param_info, element_type))
        return gjs_array_from_flat_gvalue_array(context, array, length, value_p);

    /* Special case array(guint8) */
    if (element_type == GI_TYPE_TAG_UINT8) {
        JSObject* obj = gjs_byte_array_from_data(context, length, array);
        if (!obj)
            return false;
        value_p.setObject(*obj);
        return true;
    }

    /* Special case array(unichar) to be a string in JS */
    if (element_type == GI_TYPE_TAG_UNICHAR)
        return gjs_string_from_ucs4(context, (gunichar *) array, length, value_p);

    // a null array pointer takes precedence over whatever `length` says
    if (!array) {
        JSObject* jsarray = JS::NewArrayObject(context, 0);
        if (!jsarray)
            return false;
        value_p.setObject(*jsarray);
        return true;
    }

    JS::RootedValueVector elems(context);
    if (!elems.resize(length)) {
        JS_ReportOutOfMemory(context);
        return false;
    }

    switch (element_type) {
        /* Special cases handled above */
        case GI_TYPE_TAG_UINT8:
        case GI_TYPE_TAG_UNICHAR:
            g_assert_not_reached();
        case GI_TYPE_TAG_BOOLEAN:
            if (!fill_vector_from_carray<gboolean, GI_TYPE_TAG_BOOLEAN>(
                    context, elems, param_info, &arg, array, length))
                return false;
            break;
        case GI_TYPE_TAG_INT8:
            if (!fill_vector_from_carray<int8_t>(context, elems, param_info,
                                                 &arg, array, length))
                return false;
            break;
        case GI_TYPE_TAG_UINT16:
            if (!fill_vector_from_carray<uint16_t>(context, elems, param_info,
                                                   &arg, array, length))
                return false;
            break;
        case GI_TYPE_TAG_INT16:
            if (!fill_vector_from_carray<int16_t>(context, elems, param_info,
                                                  &arg, array, length))
                return false;
            break;
        case GI_TYPE_TAG_UINT32:
            if (!fill_vector_from_carray<uint32_t>(context, elems, param_info,
                                                   &arg, array, length))
                return false;
            break;
        case GI_TYPE_TAG_INT32:
            if (!fill_vector_from_carray<int32_t>(context, elems, param_info,
                                                  &arg, array, length))
                return false;
            break;
        case GI_TYPE_TAG_UINT64:
            if (!fill_vector_from_carray<uint64_t>(context, elems, param_info,
                                                   &arg, array, length))
                return false;
            break;
        case GI_TYPE_TAG_INT64:
            if (!fill_vector_from_carray<int64_t>(context, elems, param_info,
                                                  &arg, array, length))
                return false;
            break;
        case GI_TYPE_TAG_FLOAT:
            if (!fill_vector_from_carray<float>(context, elems, param_info,
                                                &arg, array, length))
                return false;
            break;
        case GI_TYPE_TAG_DOUBLE:
            if (!fill_vector_from_carray<double>(context, elems, param_info,
                                                 &arg, array, length))
                return false;
            break;
        case GI_TYPE_TAG_INTERFACE: {
            GjsAutoBaseInfo interface_info =
                g_type_info_get_interface(param_info);
            GIInfoType info_type = g_base_info_get_type (interface_info);

            if (array_type != GI_ARRAY_TYPE_PTR_ARRAY &&
                (info_type == GI_INFO_TYPE_STRUCT ||
                 info_type == GI_INFO_TYPE_UNION) &&
                !g_type_info_is_pointer(param_info)) {
                size_t struct_size;

                if (info_type == GI_INFO_TYPE_UNION)
                    struct_size = g_union_info_get_size(interface_info);
                else
                    struct_size = g_struct_info_get_size(interface_info);

                for (i = 0; i < length; i++) {
                    gjs_arg_set(&arg,
                                static_cast<char*>(array) + (struct_size * i));

                    if (!gjs_value_from_g_argument(context, elems[i], param_info,
                                                   &arg, true))
                        return false;
                }

                break;
            }
        }
        /* fallthrough */
        case GI_TYPE_TAG_GTYPE:
        case GI_TYPE_TAG_UTF8:
        case GI_TYPE_TAG_FILENAME:
        case GI_TYPE_TAG_ARRAY:
        case GI_TYPE_TAG_GLIST:
        case GI_TYPE_TAG_GSLIST:
        case GI_TYPE_TAG_GHASH:
        case GI_TYPE_TAG_ERROR:
            if (!fill_vector_from_carray<void*>(context, elems, param_info,
                                                &arg, array, length))
                return false;
            break;
        case GI_TYPE_TAG_VOID:
        default:
          gjs_throw(context, "Unknown Array element-type %d", element_type);
          return false;
    }

    JS::RootedObject obj(context, JS::NewArrayObject(context, elems));
    if (!obj)
        return false;

    value_p.setObject(*obj);

    return true;
}

GJS_JSAPI_RETURN_CONVENTION
static bool
gjs_array_from_fixed_size_array (JSContext             *context,
                                 JS::MutableHandleValue value_p,
                                 GITypeInfo            *type_info,
                                 gpointer               array)
{
    gint length;

    length = g_type_info_get_array_fixed_size(type_info);

    g_assert (length != -1);

    GjsAutoTypeInfo param_info = g_type_info_get_param_type(type_info, 0);

    return gjs_array_from_carray_internal(context, value_p,
                                          g_type_info_get_array_type(type_info),
                                          param_info, length, array);
}

bool
gjs_value_from_explicit_array(JSContext             *context,
                              JS::MutableHandleValue value_p,
                              GITypeInfo            *type_info,
                              GIArgument            *arg,
                              int                    length)
{
    GjsAutoTypeInfo param_info = g_type_info_get_param_type(type_info, 0);

    return gjs_array_from_carray_internal(
        context, value_p, g_type_info_get_array_type(type_info), param_info,
        length, gjs_arg_get<void*>(arg));
}

GJS_JSAPI_RETURN_CONVENTION
static bool
gjs_array_from_boxed_array (JSContext             *context,
                            JS::MutableHandleValue value_p,
                            GIArrayType            array_type,
                            GITypeInfo            *param_info,
                            GArgument             *arg)
{
    GArray *array;
    GPtrArray *ptr_array;
    gpointer data = NULL;
    gsize length = 0;

    if (!gjs_arg_get<void*>(arg)) {
        value_p.setNull();
        return true;
    }

    switch(array_type) {
    case GI_ARRAY_TYPE_BYTE_ARRAY:
        /* GByteArray is just a typedef for GArray internally */
    case GI_ARRAY_TYPE_ARRAY:
        array = gjs_arg_get<GArray*>(arg);
        data = array->data;
        length = array->len;
        break;
    case GI_ARRAY_TYPE_PTR_ARRAY:
        ptr_array = gjs_arg_get<GPtrArray*>(arg);
        data = ptr_array->pdata;
        length = ptr_array->len;
        break;
    case GI_ARRAY_TYPE_C: /* already checked in gjs_value_from_g_argument() */
    default:
        g_assert_not_reached();
    }

    return gjs_array_from_carray_internal(context, value_p, array_type,
                                          param_info, length, data);
}

GJS_JSAPI_RETURN_CONVENTION
bool gjs_array_from_g_value_array(JSContext* cx, JS::MutableHandleValue value_p,
                                  GITypeInfo* param_info,
                                  const GValue* gvalue) {
    void* data = nullptr;
    size_t length = 0;
    GIArrayType array_type;
    GType value_gtype = G_VALUE_TYPE(gvalue);

    // GByteArray is just a typedef for GArray internally
    if (g_type_is_a(value_gtype, G_TYPE_BYTE_ARRAY) ||
        g_type_is_a(value_gtype, G_TYPE_ARRAY)) {
        array_type = g_type_is_a(value_gtype, G_TYPE_BYTE_ARRAY)
                         ? GI_ARRAY_TYPE_BYTE_ARRAY
                         : GI_ARRAY_TYPE_ARRAY;
        auto* array = reinterpret_cast<GArray*>(g_value_get_boxed(gvalue));
        data = array->data;
        length = array->len;
    } else if (g_type_is_a(value_gtype, G_TYPE_PTR_ARRAY)) {
        array_type = GI_ARRAY_TYPE_PTR_ARRAY;
        auto* ptr_array =
            reinterpret_cast<GPtrArray*>(g_value_get_boxed(gvalue));
        data = ptr_array->pdata;
        length = ptr_array->len;
    } else {
        g_assert_not_reached();
    }

    return gjs_array_from_carray_internal(cx, value_p, array_type, param_info,
                                          length, data);
}

template <typename T>
GJS_JSAPI_RETURN_CONVENTION static bool fill_vector_from_zero_terminated_carray(
    JSContext* cx, JS::RootedValueVector& elems,  // NOLINT(runtime/references)
    GITypeInfo* param_info, GIArgument* arg, void* c_array) {
    T* array = static_cast<T*>(c_array);

    for (size_t i = 0; array[i]; i++) {
        gjs_arg_set(arg, array[i]);

        if (!elems.growBy(1)) {
            JS_ReportOutOfMemory(cx);
            return false;
        }

        if (!gjs_value_from_g_argument(cx, elems[i], param_info, arg, true))
            return false;
    }

    return true;
}

GJS_JSAPI_RETURN_CONVENTION
static bool
gjs_array_from_zero_terminated_c_array (JSContext             *context,
                                        JS::MutableHandleValue value_p,
                                        GITypeInfo            *param_info,
                                        gpointer               c_array)
{
    GArgument arg;
    GITypeTag element_type;

    element_type = g_type_info_get_tag(param_info);

    /* Special case array(guint8) */
    if (element_type == GI_TYPE_TAG_UINT8) {
        size_t len = strlen(static_cast<char*>(c_array));
        JSObject* obj = gjs_byte_array_from_data(context, len, c_array);
        if (!obj)
            return false;
        value_p.setObject(*obj);
        return true;
    }

    /* Special case array(gunichar) to JS string */
    if (element_type == GI_TYPE_TAG_UNICHAR)
        return gjs_string_from_ucs4(context, (gunichar *) c_array, -1, value_p);

    JS::RootedValueVector elems(context);

    switch (element_type) {
        /* Special cases handled above. */
        case GI_TYPE_TAG_UINT8:
        case GI_TYPE_TAG_UNICHAR:
            g_assert_not_reached();
        case GI_TYPE_TAG_INT8:
            if (!fill_vector_from_zero_terminated_carray<int8_t>(
                    context, elems, param_info, &arg, c_array))
                return false;
            break;
        case GI_TYPE_TAG_UINT16:
            if (!fill_vector_from_zero_terminated_carray<uint16_t>(
                    context, elems, param_info, &arg, c_array))
                return false;
            break;
        case GI_TYPE_TAG_INT16:
            if (!fill_vector_from_zero_terminated_carray<int16_t>(
                    context, elems, param_info, &arg, c_array))
                return false;
            break;
        case GI_TYPE_TAG_UINT32:
            if (!fill_vector_from_zero_terminated_carray<uint32_t>(
                    context, elems, param_info, &arg, c_array))
                return false;
            break;
        case GI_TYPE_TAG_INT32:
            if (!fill_vector_from_zero_terminated_carray<int32_t>(
                    context, elems, param_info, &arg, c_array))
                return false;
            break;
        case GI_TYPE_TAG_UINT64:
            if (!fill_vector_from_zero_terminated_carray<uint64_t>(
                    context, elems, param_info, &arg, c_array))
                return false;
            break;
        case GI_TYPE_TAG_INT64:
            if (!fill_vector_from_zero_terminated_carray<int64_t>(
                    context, elems, param_info, &arg, c_array))
                return false;
            break;
        case GI_TYPE_TAG_FLOAT:
            if (!fill_vector_from_zero_terminated_carray<float>(
                    context, elems, param_info, &arg, c_array))
                return false;
            break;
        case GI_TYPE_TAG_DOUBLE:
            if (!fill_vector_from_zero_terminated_carray<double>(
                    context, elems, param_info, &arg, c_array))
                return false;
            break;
        case GI_TYPE_TAG_GTYPE:
        case GI_TYPE_TAG_UTF8:
        case GI_TYPE_TAG_FILENAME:
        case GI_TYPE_TAG_ARRAY:
        case GI_TYPE_TAG_INTERFACE:
        case GI_TYPE_TAG_GLIST:
        case GI_TYPE_TAG_GSLIST:
        case GI_TYPE_TAG_GHASH:
        case GI_TYPE_TAG_ERROR:
            if (!fill_vector_from_zero_terminated_carray<void*>(
                    context, elems, param_info, &arg, c_array))
                return false;
            break;
        /* Boolean zero-terminated array makes no sense, because FALSE is also
         * zero */
        case GI_TYPE_TAG_BOOLEAN:
            gjs_throw(context, "Boolean zero-terminated array not supported");
            return false;
        case GI_TYPE_TAG_VOID:
        default:
          gjs_throw(context, "Unknown element-type %d", element_type);
          return false;
    }

    JS::RootedObject obj(context, JS::NewArrayObject(context, elems));
    if (!obj)
        return false;

    value_p.setObject(*obj);

    return true;
}

GJS_JSAPI_RETURN_CONVENTION
static bool
gjs_object_from_g_hash (JSContext             *context,
                        JS::MutableHandleValue value_p,
                        GITypeInfo            *key_param_info,
                        GITypeInfo            *val_param_info,
                        GHashTable            *hash)
{
    GHashTableIter iter;
    GArgument keyarg, valarg;

    // a NULL hash table becomes a null JS value
    if (hash==NULL) {
        value_p.setNull();
        return true;
    }

    JS::RootedObject obj(context, JS_NewPlainObject(context));
    if (!obj)
        return false;

    value_p.setObject(*obj);

    JS::RootedValue keyjs(context), valjs(context);
    JS::RootedString keystr(context);

    g_hash_table_iter_init(&iter, hash);
    void* key_pointer;
    void* val_pointer;
    while (g_hash_table_iter_next(&iter, &key_pointer, &val_pointer)) {
        g_type_info_argument_from_hash_pointer(key_param_info, key_pointer,
                                               &keyarg);
        if (!gjs_value_from_g_argument(context, &keyjs,
                                       key_param_info, &keyarg,
                                       true))
            return false;

        keystr = JS::ToString(context, keyjs);
        if (!keystr)
            return false;

        JS::UniqueChars keyutf8(JS_EncodeStringToUTF8(context, keystr));
        if (!keyutf8)
            return false;

        g_type_info_argument_from_hash_pointer(val_param_info, val_pointer,
                                               &valarg);
        if (!gjs_value_from_g_argument(context, &valjs,
                                       val_param_info, &valarg,
                                       true))
            return false;

        if (!JS_DefineProperty(context, obj, keyutf8.get(), valjs,
                               JSPROP_ENUMERATE))
            return false;
    }

    return true;
}

bool
gjs_value_from_g_argument (JSContext             *context,
                           JS::MutableHandleValue value_p,
                           GITypeInfo            *type_info,
                           GArgument             *arg,
                           bool                   copy_structs)
{
    GITypeTag type_tag;

    type_tag = g_type_info_get_tag( (GITypeInfo*) type_info);

    gjs_debug_marshal(GJS_DEBUG_GFUNCTION,
                      "Converting GArgument %s to JS::Value",
                      g_type_tag_to_string(type_tag));

    value_p.setNull();

    switch (type_tag) {
    case GI_TYPE_TAG_VOID:
        value_p.setUndefined(); /* or .setNull() ? */
        break;

    case GI_TYPE_TAG_BOOLEAN:
        value_p.setBoolean(gjs_arg_get<bool>(arg));
        break;

    case GI_TYPE_TAG_INT32:
        value_p.setInt32(gjs_arg_get<int32_t>(arg));
        break;

    case GI_TYPE_TAG_UINT32:
        value_p.setNumber(gjs_arg_get<uint32_t>(arg));
        break;

    case GI_TYPE_TAG_INT64:
        value_p.setNumber(gjs_arg_get_maybe_rounded<int64_t>(arg));
        break;

    case GI_TYPE_TAG_UINT64:
        value_p.setNumber(gjs_arg_get_maybe_rounded<uint64_t>(arg));
        break;

    case GI_TYPE_TAG_UINT16:
        value_p.setInt32(gjs_arg_get<uint16_t>(arg));
        break;

    case GI_TYPE_TAG_INT16:
        value_p.setInt32(gjs_arg_get<int16_t>(arg));
        break;

    case GI_TYPE_TAG_UINT8:
        value_p.setInt32(gjs_arg_get<uint8_t>(arg));
        break;

    case GI_TYPE_TAG_INT8:
        value_p.setInt32(gjs_arg_get<int8_t>(arg));
        break;

    case GI_TYPE_TAG_FLOAT:
        value_p.setNumber(gjs_arg_get<float>(arg));
        break;

    case GI_TYPE_TAG_DOUBLE:
        value_p.setNumber(gjs_arg_get<double>(arg));
        break;

    case GI_TYPE_TAG_GTYPE:
    {
        GType gtype = gjs_arg_get<GType, GI_TYPE_TAG_GTYPE>(arg);
        if (gtype == 0)
            return true;  /* value_p is set to JS null */

        JS::RootedObject obj(context, gjs_gtype_create_gtype_wrapper(context, gtype));
        if (!obj)
            return false;

        value_p.setObject(*obj);
        return true;
    }
        break;

    case GI_TYPE_TAG_UNICHAR: {
        char32_t value = gjs_arg_get<char32_t>(arg);

        // Preserve the bidirectional mapping between 0 and ""
        if (value == 0) {
            value_p.set(JS_GetEmptyStringValue(context));
            return true;
        } else if (!g_unichar_validate(value)) {
            gjs_throw(context, "Invalid unicode codepoint %" G_GUINT32_FORMAT,
                      value);
            return false;
        }

        char utf8[7];
        int bytes = g_unichar_to_utf8(value, utf8);
        return gjs_string_from_utf8_n(context, utf8, bytes, value_p);
    }

    case GI_TYPE_TAG_FILENAME:
    case GI_TYPE_TAG_UTF8: {
        const char* str = gjs_arg_get<const char*>(arg);
        // For nullptr we'll return JS::NullValue(), which is already set
        // in *value_p
        if (!str)
            return true;

        if (type_tag == GI_TYPE_TAG_FILENAME)
            return gjs_string_from_filename(context, str, -1, value_p);

        return gjs_string_from_utf8(context, str, value_p);
    }

    case GI_TYPE_TAG_ERROR: {
        GError* ptr = gjs_arg_get<GError*>(arg);
        if (!ptr)
            return true;

        JSObject* obj = ErrorInstance::object_for_c_ptr(context, ptr);
        if (!obj)
            return false;

        value_p.setObject(*obj);
        return true;
    }

    case GI_TYPE_TAG_INTERFACE:
        {
            GIInfoType interface_type;
            GType gtype;

            GjsAutoBaseInfo interface_info =
                g_type_info_get_interface(type_info);
            g_assert(interface_info);

            interface_type = g_base_info_get_type(interface_info);

            if (interface_type == GI_INFO_TYPE_UNRESOLVED) {
                gjs_throw(context,
                          "Unable to resolve arg type '%s'",
                          g_base_info_get_name(interface_info));
                return false;
            }

            /* Enum/Flags are aren't pointer types, unlike the other interface subtypes */
            if (interface_type == GI_INFO_TYPE_ENUM) {
                int64_t value_int64 = _gjs_enum_from_int(
                    interface_info,
                    gjs_arg_get<int, GI_TYPE_TAG_INTERFACE>(arg));

                if (!_gjs_enum_value_is_valid(context, interface_info,
                                              value_int64))
                    return false;

                value_p.setNumber(static_cast<double>(value_int64));
                return true;
            }

            if (interface_type == GI_INFO_TYPE_FLAGS) {
                int64_t value_int64 = _gjs_enum_from_int(
                    interface_info,
                    gjs_arg_get<int, GI_TYPE_TAG_INTERFACE>(arg));

                gtype = g_registered_type_info_get_g_type((GIRegisteredTypeInfo*)interface_info);
                if (!_gjs_flags_value_is_valid(context, gtype, value_int64))
                    return false;

                value_p.setNumber(static_cast<double>(value_int64));
                return true;
            }

            if (interface_type == GI_INFO_TYPE_STRUCT &&
                g_struct_info_is_foreign((GIStructInfo*)interface_info)) {
                return gjs_struct_foreign_convert_from_g_argument(
                    context, value_p, interface_info, arg);
            }

            /* Everything else is a pointer type, NULL is the easy case */
            if (!gjs_arg_get<void*>(arg)) {
                value_p.setNull();
                return true;
            }

            if (interface_type == GI_INFO_TYPE_STRUCT &&
                g_struct_info_is_gtype_struct((GIStructInfo*)interface_info)) {
                /* XXX: here we make the implicit assumption that GTypeClass is the same
                   as GTypeInterface. This is true for the GType field, which is what we
                   use, but not for the rest of the structure!
                */
                gtype = G_TYPE_FROM_CLASS(gjs_arg_get<GTypeClass*>(arg));

                if (g_type_is_a(gtype, G_TYPE_INTERFACE)) {
                    return gjs_lookup_interface_constructor(context, gtype,
                                                            value_p);
                }
                return gjs_lookup_object_constructor(context, gtype, value_p);
            }

            gtype = g_registered_type_info_get_g_type((GIRegisteredTypeInfo*)interface_info);
            if (G_TYPE_IS_INSTANTIATABLE(gtype) ||
                G_TYPE_IS_INTERFACE(gtype))
                gtype = G_TYPE_FROM_INSTANCE(gjs_arg_get<GTypeInstance*>(arg));

            gjs_debug_marshal(GJS_DEBUG_GFUNCTION,
                              "gtype of INTERFACE is %s", g_type_name(gtype));


            /* Test GValue and GError before Struct, or it will be handled as the latter */
            if (g_type_is_a(gtype, G_TYPE_VALUE)) {
                return gjs_value_from_g_value(context, value_p,
                                              gjs_arg_get<const GValue*>(arg));
            }

            if (g_type_is_a(gtype, G_TYPE_ERROR)) {
                JSObject* obj = ErrorInstance::object_for_c_ptr(
                    context, gjs_arg_get<GError*>(arg));
                if (!obj)
                    return false;
                value_p.setObject(*obj);
                return true;
            }

            if (interface_type == GI_INFO_TYPE_STRUCT || interface_type == GI_INFO_TYPE_BOXED) {
                if (is_gdk_atom(interface_info)) {
                    GjsAutoFunctionInfo atom_name_fun =
                        g_struct_info_find_method(interface_info, "name");
                    GIArgument atom_name_ret;

                    g_function_info_invoke(atom_name_fun,
                            arg, 1,
                            nullptr, 0,
                            &atom_name_ret,
                            nullptr);

                    GjsAutoChar name = gjs_arg_get<char*>(&atom_name_ret);
                    if (g_strcmp0("NONE", name) == 0) {
                        value_p.setNull();
                        return true;
                    }

                    return gjs_string_from_utf8(context, name, value_p);
                }

                JSObject *obj;

                if (copy_structs || g_type_is_a(gtype, G_TYPE_VARIANT))
                    obj = BoxedInstance::new_for_c_struct(
                        context, interface_info, gjs_arg_get<GVariant*>(arg));
                else
                    obj = BoxedInstance::new_for_c_struct(
                        context, interface_info, gjs_arg_get<void*>(arg),
                        BoxedInstance::NoCopy());

                if (!obj)
                    return false;

                value_p.setObject(*obj);
                return true;
            }

            if (interface_type == GI_INFO_TYPE_UNION) {
                JSObject* obj = gjs_union_from_c_union(
                    context, static_cast<GIUnionInfo*>(interface_info),
                    gjs_arg_get<void*>(arg));
                if (!obj)
                    return false;

                value_p.setObject(*obj);
                return true;
            }

            if (g_type_is_a(gtype, G_TYPE_OBJECT)) {
                g_assert(gjs_arg_get<void*>(arg) &&
                         "Null arg is already handled above");
                return ObjectInstance::set_value_from_gobject(
                    context, gjs_arg_get<GObject*>(arg), value_p);
            }

            if (g_type_is_a(gtype, G_TYPE_BOXED) ||
                g_type_is_a(gtype, G_TYPE_ENUM) ||
                g_type_is_a(gtype, G_TYPE_FLAGS)) {
                /* Should have been handled above */
                gjs_throw(context,
                          "Type %s registered for unexpected interface_type %d",
                          g_type_name(gtype),
                          interface_type);
                return false;
            }

            if (g_type_is_a(gtype, G_TYPE_PARAM)) {
                JSObject* obj = gjs_param_from_g_param(
                    context, G_PARAM_SPEC(gjs_arg_get<GParamSpec*>(arg)));
                if (!obj)
                    return false;
                value_p.setObject(*obj);
                return true;
            }

            if (gtype == G_TYPE_NONE) {
                gjs_throw(context, "Unexpected unregistered type packing GArgument into JS::Value");
                return false;
            }

            if (G_TYPE_IS_INSTANTIATABLE(gtype) || G_TYPE_IS_INTERFACE(gtype)) {
                JSObject* obj = FundamentalInstance::object_for_c_ptr(
                    context, gjs_arg_get<void*>(arg));
                if (!obj)
                    return false;
                value_p.setObject(*obj);
                return true;
            }

            gjs_throw(context,
                      "Unhandled GType %s packing GArgument into JS::Value",
                      g_type_name(gtype));
            return false;
        }

    case GI_TYPE_TAG_ARRAY:
        if (!gjs_arg_get<void*>(arg)) {
            /* OK, but no conversion to do */
        } else if (g_type_info_get_array_type(type_info) == GI_ARRAY_TYPE_C) {
            if (g_type_info_is_zero_terminated(type_info)) {
                GjsAutoBaseInfo param_info =
                    g_type_info_get_interface(type_info);

                param_info = g_type_info_get_param_type(type_info, 0);
                g_assert(param_info != nullptr);

                return gjs_array_from_zero_terminated_c_array(
                    context, value_p, param_info, gjs_arg_get<void*>(arg));
            } else {
                /* arrays with length are handled outside of this function */
                g_assert(((void) "Use gjs_value_from_explicit_array() for "
                          "arrays with length param",
                          g_type_info_get_array_length(type_info) == -1));
                return gjs_array_from_fixed_size_array(
                    context, value_p, type_info, gjs_arg_get<void*>(arg));
            }
        } else if (g_type_info_get_array_type(type_info) ==
                   GI_ARRAY_TYPE_BYTE_ARRAY) {
            auto* byte_array = gjs_arg_get<GByteArray*>(arg);
            JSObject* array =
                gjs_byte_array_from_byte_array(context, byte_array);
            if (!array) {
                gjs_throw(context,
                          "Couldn't convert GByteArray to a Uint8Array");
                return false;
            }
            value_p.setObject(*array);
        } else {
            /* this assumes the array type is one of GArray, GPtrArray or
             * GByteArray */
            GjsAutoTypeInfo param_info =
                g_type_info_get_param_type(type_info, 0);
            g_assert(param_info != nullptr);

            return gjs_array_from_boxed_array(
                context, value_p, g_type_info_get_array_type(type_info),
                param_info, arg);
        }
        break;

    case GI_TYPE_TAG_GLIST:
        return gjs_array_from_g_list(context, value_p, type_info,
                                     gjs_arg_get<GList*>(arg));
    case GI_TYPE_TAG_GSLIST:
        return gjs_array_from_g_list(context, value_p, type_info,
                                     gjs_arg_get<GSList*>(arg));

    case GI_TYPE_TAG_GHASH:
        {
        GjsAutoTypeInfo key_param_info =
            g_type_info_get_param_type(type_info, 0);
        GjsAutoTypeInfo val_param_info =
            g_type_info_get_param_type(type_info, 1);
        g_assert(key_param_info != nullptr);
        g_assert(val_param_info != nullptr);

        return gjs_object_from_g_hash(context, value_p, key_param_info,
                                      val_param_info,
                                      gjs_arg_get<GHashTable*>(arg));
        }
        break;

    default:
        g_warning("Unhandled type %s converting GArgument to JavaScript",
                  g_type_tag_to_string(type_tag));
        return false;
    }

    return true;
}

struct GHR_closure {
    JSContext *context;
    GjsAutoTypeInfo key_param_info, val_param_info;
    GITransfer transfer;
    bool failed;
};

static gboolean
gjs_ghr_helper(gpointer key, gpointer val, gpointer user_data) {
    GHR_closure *c = (GHR_closure *) user_data;
    GArgument key_arg, val_arg;
    gjs_arg_set(&key_arg, key);
    gjs_arg_set(&val_arg, val);
    if (!gjs_g_arg_release_internal(c->context, c->transfer,
                                    c->key_param_info,
                                    g_type_info_get_tag(c->key_param_info),
                                    &key_arg))
        c->failed = true;

    GITypeTag val_type = g_type_info_get_tag(c->val_param_info);

    switch (val_type) {
        case GI_TYPE_TAG_DOUBLE:
        case GI_TYPE_TAG_FLOAT:
        case GI_TYPE_TAG_INT64:
        case GI_TYPE_TAG_UINT64:
            g_clear_pointer(&gjs_arg_member<void*>(&val_arg), g_free);
            break;

        default:
            if (!gjs_g_arg_release_internal(c->context, c->transfer,
                                            c->val_param_info, val_type,
                                            &val_arg))
                c->failed = true;
    }

    return true;
}

/* We need to handle GI_TRANSFER_NOTHING differently for out parameters
 * (free nothing) and for in parameters (free any temporaries we've
 * allocated
 */
#define TRANSFER_IN_NOTHING (GI_TRANSFER_EVERYTHING + 1)

GJS_JSAPI_RETURN_CONVENTION
static bool
gjs_g_arg_release_internal(JSContext  *context,
                           GITransfer  transfer,
                           GITypeInfo *type_info,
                           GITypeTag   type_tag,
                           GArgument  *arg)
{
    g_assert(transfer != GI_TRANSFER_NOTHING);

    switch (type_tag) {
    case GI_TYPE_TAG_VOID:
    case GI_TYPE_TAG_BOOLEAN:
    case GI_TYPE_TAG_INT8:
    case GI_TYPE_TAG_UINT8:
    case GI_TYPE_TAG_INT16:
    case GI_TYPE_TAG_UINT16:
    case GI_TYPE_TAG_INT32:
    case GI_TYPE_TAG_UINT32:
    case GI_TYPE_TAG_INT64:
    case GI_TYPE_TAG_UINT64:
    case GI_TYPE_TAG_FLOAT:
    case GI_TYPE_TAG_DOUBLE:
    case GI_TYPE_TAG_UNICHAR:
    case GI_TYPE_TAG_GTYPE:
        break;

    case GI_TYPE_TAG_FILENAME:
    case GI_TYPE_TAG_UTF8:
        g_clear_pointer(&gjs_arg_member<char*>(arg), g_free);
        break;

    case GI_TYPE_TAG_ERROR:
        if (transfer != TRANSFER_IN_NOTHING)
            g_clear_error(&gjs_arg_member<GError*>(arg));
        break;

    case GI_TYPE_TAG_INTERFACE:
        {
            GIInfoType interface_type;
            GType gtype;

            GjsAutoBaseInfo interface_info =
                g_type_info_get_interface(type_info);
            g_assert(interface_info);

            interface_type = g_base_info_get_type(interface_info);

            if (interface_type == GI_INFO_TYPE_STRUCT &&
                g_struct_info_is_foreign((GIStructInfo*)interface_info))
                return gjs_struct_foreign_release_g_argument(context,
                        transfer, interface_info, arg);

            if (interface_type == GI_INFO_TYPE_ENUM || interface_type == GI_INFO_TYPE_FLAGS)
                return true;

            /* Anything else is a pointer */
            if (!gjs_arg_get<void*>(arg))
                return true;

            gtype = g_registered_type_info_get_g_type((GIRegisteredTypeInfo*)interface_info);
            if (G_TYPE_IS_INSTANTIATABLE(gtype) ||
                G_TYPE_IS_INTERFACE(gtype))
                gtype = G_TYPE_FROM_INSTANCE(gjs_arg_get<GTypeInstance*>(arg));

            gjs_debug_marshal(GJS_DEBUG_GFUNCTION,
                              "gtype of INTERFACE is %s", g_type_name(gtype));

            /* In gjs_value_from_g_argument we handle Struct/Union types without a
             * registered GType, but here we are specifically handling a GArgument that
             * *owns* its value, and that is non-sensical for such types, so we
             * don't have to worry about it.
             */

            if (g_type_is_a(gtype, G_TYPE_OBJECT)) {
                if (transfer != TRANSFER_IN_NOTHING)
                    g_clear_object(&gjs_arg_member<GObject*>(arg));
            } else if (g_type_is_a(gtype, G_TYPE_PARAM)) {
                if (transfer != TRANSFER_IN_NOTHING)
                    g_clear_pointer(&gjs_arg_member<GParamSpec*>(arg),
                                    g_param_spec_unref);
            } else if (g_type_is_a(gtype, G_TYPE_CLOSURE)) {
                g_clear_pointer(&gjs_arg_member<GClosure*>(arg),
                                g_closure_unref);
            } else if (g_type_is_a(gtype, G_TYPE_VALUE)) {
                /* G_TYPE_VALUE is-a G_TYPE_BOXED, but we special case it */
                if (g_type_info_is_pointer (type_info))
                    g_boxed_free(gtype, gjs_arg_steal<void*>(arg));
                else
                    g_clear_pointer(&gjs_arg_member<GValue*>(arg),
                                    g_value_unset);
            } else if (g_type_is_a(gtype, G_TYPE_BOXED)) {
                if (transfer != TRANSFER_IN_NOTHING)
                    g_boxed_free(gtype, gjs_arg_steal<void*>(arg));
            } else if (g_type_is_a(gtype, G_TYPE_VARIANT)) {
                if (transfer != TRANSFER_IN_NOTHING)
                    g_clear_pointer(&gjs_arg_member<GVariant*>(arg),
                                    g_variant_unref);
            } else if (gtype == G_TYPE_NONE) {
                if (transfer != TRANSFER_IN_NOTHING) {
                    gjs_throw(context, "Don't know how to release GArgument: not an object or boxed type");
                    return false;
                }
            } else if (G_TYPE_IS_INSTANTIATABLE(gtype)) {
                if (transfer != TRANSFER_IN_NOTHING) {
                    auto* priv =
                        FundamentalPrototype::for_gtype(context, gtype);
                    priv->call_unref_function(gjs_arg_steal<void*>(arg));
                }
            } else {
                gjs_throw(context, "Unhandled GType %s releasing GArgument",
                          g_type_name(gtype));
                return false;
            }
            return true;
        }

    case GI_TYPE_TAG_ARRAY:
    {
        GIArrayType array_type = g_type_info_get_array_type(type_info);

        if (!gjs_arg_get<void*>(arg)) {
            /* OK */
        } else if (array_type == GI_ARRAY_TYPE_C) {
            GjsAutoTypeInfo param_info =
                g_type_info_get_param_type(type_info, 0);
            GITypeTag element_type;

            element_type = g_type_info_get_tag(param_info);

            if (is_gvalue_flat_array(param_info, element_type)) {
                if (transfer != GI_TRANSFER_CONTAINER) {
                    gint len = g_type_info_get_array_fixed_size(type_info);
                    gint i;

                    if (len < 0) {
                        gjs_throw(context,
                                  "Releasing a flat GValue array that was not fixed-size or was nested"
                                  "inside another container. This is not supported (and will leak)");
                        return false;
                    }

                    for (i = 0; i < len; i++) {
                        GValue* v = gjs_arg_get<GValue*>(arg) + i;
                        g_value_unset(v);
                    }
                }

                g_clear_pointer(&gjs_arg_member<void*>(arg), g_free);
                return true;
            }

            switch (element_type) {
            case GI_TYPE_TAG_UTF8:
            case GI_TYPE_TAG_FILENAME:
                if (transfer == GI_TRANSFER_CONTAINER)
                    g_clear_pointer(&gjs_arg_member<void*>(arg),
                                    g_free);
                else
                    g_clear_pointer(&gjs_arg_member<GStrv>(arg),
                                    g_strfreev);
                break;

            case GI_TYPE_TAG_BOOLEAN:
            case GI_TYPE_TAG_UINT8:
            case GI_TYPE_TAG_UINT16:
            case GI_TYPE_TAG_UINT32:
            case GI_TYPE_TAG_UINT64:
            case GI_TYPE_TAG_INT8:
            case GI_TYPE_TAG_INT16:
            case GI_TYPE_TAG_INT32:
            case GI_TYPE_TAG_INT64:
            case GI_TYPE_TAG_FLOAT:
            case GI_TYPE_TAG_DOUBLE:
            case GI_TYPE_TAG_UNICHAR:
            case GI_TYPE_TAG_GTYPE:
                g_clear_pointer(&gjs_arg_member<void*>(arg), g_free);
                break;

            case GI_TYPE_TAG_INTERFACE:
                if (!g_type_info_is_pointer(param_info)) {
                    GjsAutoBaseInfo interface_info =
                        g_type_info_get_interface(param_info);
                    GIInfoType info_type = g_base_info_get_type(interface_info);
                    if (info_type == GI_INFO_TYPE_STRUCT ||
                        info_type == GI_INFO_TYPE_UNION) {
                        g_clear_pointer(&gjs_arg_member<void*>(arg), g_free);
                        break;
                    }
                }
                [[fallthrough]];
            case GI_TYPE_TAG_GLIST:
            case GI_TYPE_TAG_GSLIST:
            case GI_TYPE_TAG_ARRAY:
            case GI_TYPE_TAG_GHASH:
            case GI_TYPE_TAG_ERROR: {
                GjsAutoPointer<void*, void, g_free> arg_array =
                    gjs_arg_steal<void**>(arg);
                if (transfer != GI_TRANSFER_CONTAINER
                    && type_needs_out_release(param_info, element_type)) {
                    if (g_type_info_is_zero_terminated (type_info)) {
                        gpointer *array;
                        GArgument elem;

                        for (array = arg_array; *array; array++) {
                            gjs_arg_set(&elem, *array);
                            if (!gjs_g_arg_release_internal(context,
                                                            GI_TRANSFER_EVERYTHING,
                                                            param_info,
                                                            element_type,
                                                            &elem)) {
                                return false;
                            }
                        }
                    } else {
                        gint len = g_type_info_get_array_fixed_size(type_info);
                        gint i;
                        GArgument elem;

                        g_assert(len != -1);

                        for (i = 0; i < len; i++) {
                            gjs_arg_set(&elem, arg_array[i]);
                            if (!gjs_g_arg_release_internal(context,
                                                            GI_TRANSFER_EVERYTHING,
                                                            param_info,
                                                            element_type,
                                                            &elem)) {
                                return false;
                            }
                        }
                    }
                }
                break;
            }

            case GI_TYPE_TAG_VOID:
            default:
                gjs_throw(context,
                          "Releasing a C array with explicit length, that was nested"
                          "inside another container. This is not supported (and will leak)");
                return false;
            }
        } else if (array_type == GI_ARRAY_TYPE_ARRAY) {
            GITypeTag element_type;

            GjsAutoTypeInfo param_info =
                g_type_info_get_param_type(type_info, 0);
            element_type = g_type_info_get_tag(param_info);

            switch (element_type) {
            case GI_TYPE_TAG_BOOLEAN:
            case GI_TYPE_TAG_UNICHAR:
            case GI_TYPE_TAG_UINT8:
            case GI_TYPE_TAG_UINT16:
            case GI_TYPE_TAG_UINT32:
            case GI_TYPE_TAG_UINT64:
            case GI_TYPE_TAG_INT8:
            case GI_TYPE_TAG_INT16:
            case GI_TYPE_TAG_INT32:
            case GI_TYPE_TAG_INT64:
            case GI_TYPE_TAG_FLOAT:
            case GI_TYPE_TAG_DOUBLE:
            case GI_TYPE_TAG_GTYPE:
                g_clear_pointer(&gjs_arg_member<GArray*>(arg), g_array_unref);
                break;

            case GI_TYPE_TAG_UTF8:
            case GI_TYPE_TAG_FILENAME:
            case GI_TYPE_TAG_ARRAY:
            case GI_TYPE_TAG_INTERFACE:
            case GI_TYPE_TAG_GLIST:
            case GI_TYPE_TAG_GSLIST:
            case GI_TYPE_TAG_GHASH:
            case GI_TYPE_TAG_ERROR: {
                GjsAutoPointer<GArray, GArray, g_array_unref> array =
                    gjs_arg_steal<GArray*>(arg);

                if (transfer != GI_TRANSFER_CONTAINER &&
                    type_needs_out_release(param_info, element_type)) {
                    guint i;

                    for (i = 0; i < array->len; i++) {
                        GArgument arg_iter;

                        gjs_arg_set(&arg_iter,
                                    g_array_index(array, gpointer, i));
                        if (!gjs_g_arg_release_internal(
                                context, transfer, param_info, element_type,
                                &arg_iter))
                            return false;
                    }
                }

                break;
            }

            case GI_TYPE_TAG_VOID:
            default:
                gjs_throw(context,
                          "Don't know how to release GArray element-type %d",
                          element_type);
                return false;
            }

        } else if (array_type == GI_ARRAY_TYPE_BYTE_ARRAY) {
            g_clear_pointer(&gjs_arg_member<GByteArray*>(arg),
                            g_byte_array_unref);
        } else if (array_type == GI_ARRAY_TYPE_PTR_ARRAY) {
            GjsAutoTypeInfo param_info =
                g_type_info_get_param_type(type_info, 0);
            GjsAutoPointer<GPtrArray, GPtrArray, g_ptr_array_unref> array =
                gjs_arg_steal<GPtrArray*>(arg);

            if (transfer != GI_TRANSFER_CONTAINER) {
                guint i;

                for (i = 0; i < array->len; i++) {
                    GArgument arg_iter;

                    gjs_arg_set(&arg_iter, g_ptr_array_index(array, i));
                    if (!gjs_g_argument_release(context, transfer, param_info,
                                                &arg_iter))
                        return false;
                }
            }
        } else {
            g_assert_not_reached();
        }
        break;
    }

    case GI_TYPE_TAG_GLIST:
        return gjs_g_arg_release_g_list<GList>(context, transfer, type_info,
                                               arg);

    case GI_TYPE_TAG_GSLIST:
        return gjs_g_arg_release_g_list<GSList>(context, transfer, type_info,
                                                arg);

    case GI_TYPE_TAG_GHASH:
        if (gjs_arg_get<GHashTable*>(arg)) {
            GjsAutoPointer<GHashTable, GHashTable, g_hash_table_destroy>
                hash_table = gjs_arg_steal<GHashTable*>(arg);
            if (transfer == GI_TRANSFER_CONTAINER)
                g_hash_table_steal_all(hash_table);
            else {
                GHR_closure c = {
                    context, NULL, NULL,
                    transfer,
                    false
                };

                c.key_param_info = g_type_info_get_param_type(type_info, 0);
                g_assert(c.key_param_info != nullptr);
                c.val_param_info = g_type_info_get_param_type(type_info, 1);
                g_assert(c.val_param_info != nullptr);

                g_hash_table_foreach_steal(hash_table, gjs_ghr_helper, &c);

                if (c.failed)
                    return false;
            }
        }
        break;

    default:
        g_warning("Unhandled type %s releasing GArgument",
                  g_type_tag_to_string(type_tag));
        return false;
    }

    return true;
}

bool
gjs_g_argument_release(JSContext  *context,
                       GITransfer  transfer,
                       GITypeInfo *type_info,
                       GArgument  *arg)
{
    GITypeTag type_tag;

    if (transfer == GI_TRANSFER_NOTHING)
        return true;

    type_tag = g_type_info_get_tag( (GITypeInfo*) type_info);

    gjs_debug_marshal(GJS_DEBUG_GFUNCTION,
                      "Releasing GArgument %s out param or return value",
                      g_type_tag_to_string(type_tag));

    return gjs_g_arg_release_internal(context, transfer, type_info, type_tag, arg);
}

bool
gjs_g_argument_release_in_arg(JSContext  *context,
                              GITransfer  transfer,
                              GITypeInfo *type_info,
                              GArgument  *arg)
{
    GITypeTag type_tag;

    /* GI_TRANSFER_EVERYTHING: we don't own the argument anymore.
     * GI_TRANSFER_CONTAINER:
     * - non-containers: treated as GI_TRANSFER_EVERYTHING
     * - containers: See FIXME in gjs_array_to_g_list(); currently
     *   an error and we won't get here.
     */
    if (transfer != GI_TRANSFER_NOTHING)
        return true;

    type_tag = g_type_info_get_tag( (GITypeInfo*) type_info);

    gjs_debug_marshal(GJS_DEBUG_GFUNCTION,
                      "Releasing GArgument %s in param",
                      g_type_tag_to_string(type_tag));

    if (type_needs_release (type_info, type_tag))
        return gjs_g_arg_release_internal(context, (GITransfer) TRANSFER_IN_NOTHING,
                                          type_info, type_tag, arg);

    return true;
}

bool gjs_g_argument_release_in_array(JSContext* context, GITransfer transfer,
                                     GITypeInfo* type_info, unsigned length,
                                     GIArgument* arg) {
    GArgument elem;
    guint i;
    GITypeTag type_tag;

    if (transfer != GI_TRANSFER_NOTHING)
        return true;

    gjs_debug_marshal(GJS_DEBUG_GFUNCTION,
                      "Releasing GArgument array in param");

    GjsAutoPointer<void*, void, g_free> array = gjs_arg_steal<void**>(arg);
    GjsAutoTypeInfo param_type = g_type_info_get_param_type(type_info, 0);
    type_tag = g_type_info_get_tag(param_type);

    if (is_gvalue_flat_array(param_type, type_tag)) {
        for (i = 0; i < length; i++) {
            GValue* v = reinterpret_cast<GValue*>(array.get()) + i;
            g_value_unset(v);
        }
    }

    if (type_needs_release(param_type, type_tag)) {
        for (i = 0; i < length; i++) {
            gjs_arg_set(&elem, array[i]);
            if (!gjs_g_arg_release_internal(context, (GITransfer) TRANSFER_IN_NOTHING,
                                            param_type, type_tag, &elem)) {
                return false;
            }
        }
    }

    return true;
}

bool gjs_g_argument_release_out_array(JSContext* context, GITransfer transfer,
                                      GITypeInfo* type_info, unsigned length,
                                      GIArgument* arg) {
    GArgument elem;
    guint i;
    GITypeTag type_tag;

    if (transfer == GI_TRANSFER_NOTHING)
        return true;

    gjs_debug_marshal(GJS_DEBUG_GFUNCTION,
                      "Releasing GArgument array out param");

    GjsAutoPointer<void*, void, g_free> array = gjs_arg_steal<void**>(arg);
    GjsAutoTypeInfo param_type = g_type_info_get_param_type(type_info, 0);
    type_tag = g_type_info_get_tag(param_type);

    if (transfer != GI_TRANSFER_CONTAINER &&
        type_needs_out_release(param_type, type_tag)) {
        for (i = 0; i < length; i++) {
            gjs_arg_set(&elem, array[i]);
            JS::AutoSaveExceptionState saved_exc(context);
            if (!gjs_g_arg_release_internal(context,
                                            GI_TRANSFER_EVERYTHING,
                                            param_type,
                                            type_tag,
                                            &elem)) {
                return false;
            }
        }
    }

    return true;
}
