UXP/js/src/builtin/BigInt.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "builtin/BigInt.h"

#include "jsapi.h"

#include "builtin/TypedObject.h"
#include "gc/Tracer.h"
#include "js/TracingAPI.h"
#include "vm/ArrayBufferObject.h"
#include "vm/BigIntType.h"
#include "vm/SelfHosting.h"
#include "vm/TaggedProto.h"

#include "vm/NativeObject-inl.h"

using namespace js;

static MOZ_ALWAYS_INLINE bool
IsBigInt(HandleValue v)
{
    return v.isBigInt() || (v.isObject() && v.toObject().is<BigIntObject>());
}

static JSObject*
CreateBigIntPrototype(JSContext* cx, JSProtoKey key)
{
    return GlobalObject::createBlankPrototype<PlainObject>(cx, cx->global());
}

// BigInt proposal section 5.1.3
static bool
BigIntConstructor(JSContext* cx, unsigned argc, Value* vp)
{
    CallArgs args = CallArgsFromVp(argc, vp);

    // Step 1.
    if (args.isConstructing()) {
        JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, JSMSG_NOT_CONSTRUCTOR, "BigInt");
        return false;
    }

    // Step 2.
    RootedValue v(cx, args.get(0));
    if (!ToPrimitive(cx, JSTYPE_NUMBER, &v))
        return false;

    // Steps 3-4.
    BigInt* bi = v.isNumber()
                 ? NumberToBigInt(cx, v.toNumber())
                 : ToBigInt(cx, v);
    if (!bi)
        return false;

    args.rval().setBigInt(bi);
    return true;
}

JSObject*
BigIntObject::create(JSContext* cx, HandleBigInt bigInt)
{
    RootedObject obj(cx, NewBuiltinClassInstance(cx, &class_));
    if (!obj)
        return nullptr;
    BigIntObject& bn = obj->as<BigIntObject>();
    bn.setFixedSlot(PRIMITIVE_VALUE_SLOT, BigIntValue(bigInt));
    return &bn;
}

BigInt*
BigIntObject::unbox() const
{
    return getFixedSlot(PRIMITIVE_VALUE_SLOT).toBigInt();
}

// BigInt proposal section 5.3.4
bool
BigIntObject::valueOf_impl(JSContext* cx, const CallArgs& args)
{
    // Step 1.
    HandleValue thisv = args.thisv();
    MOZ_ASSERT(IsBigInt(thisv));
    RootedBigInt bi(cx, thisv.isBigInt()
                        ? thisv.toBigInt()
                        : thisv.toObject().as<BigIntObject>().unbox());

    args.rval().setBigInt(bi);
    return true;
}

bool
BigIntObject::valueOf(JSContext* cx, unsigned argc, Value* vp)
{
    CallArgs args = CallArgsFromVp(argc, vp);
    return CallNonGenericMethod<IsBigInt, valueOf_impl>(cx, args);
}

// BigInt proposal section 5.3.3
bool
BigIntObject::toString_impl(JSContext* cx, const CallArgs& args)
{
    // Step 1.
    HandleValue thisv = args.thisv();
    MOZ_ASSERT(IsBigInt(thisv));
    RootedBigInt bi(cx, thisv.isBigInt()
                        ? thisv.toBigInt()
                        : thisv.toObject().as<BigIntObject>().unbox());

    // Steps 2-3.
    uint8_t radix = 10;

    // Steps 4-5.
    if (args.hasDefined(0)) {
        double d;
        if (!ToInteger(cx, args.get(0), &d))
            return false;
        if (d < 2 || d > 36) {
            JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, JSMSG_BAD_RADIX);
            return false;
        }
        radix = d;
    }

    // Steps 6-7.
    JSLinearString* str = BigInt::toString(cx, bi, radix);
    if (!str)
        return false;
    args.rval().setString(str);
    return true;
}

bool
BigIntObject::toString(JSContext* cx, unsigned argc, Value* vp)
{
    CallArgs args = CallArgsFromVp(argc, vp);
    return CallNonGenericMethod<IsBigInt, toString_impl>(cx, args);
}

// BigInt proposal section 5.2.1. BigInt.asUintN ( bits, bigint )
bool
BigIntObject::asUintN(JSContext* cx, unsigned argc, Value* vp)
{
    CallArgs args = CallArgsFromVp(argc, vp);

    // Step 1.
    uint64_t bits;
    if (!ToIndex(cx, args.get(0), &bits)) {
        return false;
    }

    // Step 2.
    RootedBigInt bi(cx, ToBigInt(cx, args.get(1)));
    if (!bi) {
        return false;
    }

    // Step 3.
    BigInt* res = BigInt::asUintN(cx, bi, bits);
    if (!res) {
        return false;
    }

    args.rval().setBigInt(res);
    return true;
}

// BigInt proposal section 5.2.2. BigInt.asIntN ( bits, bigint )
bool
BigIntObject::asIntN(JSContext* cx, unsigned argc, Value* vp)
{
    CallArgs args = CallArgsFromVp(argc, vp);

    // Step 1.
    uint64_t bits;
    if (!ToIndex(cx, args.get(0), &bits)) {
        return false;
    }

    // Step 2.
    RootedBigInt bi(cx, ToBigInt(cx, args.get(1)));
    if (!bi) {
        return false;
    }

    // Step 3.
    BigInt* res = BigInt::asIntN(cx, bi, bits);
    if (!res) {
        return false;
    }

    args.rval().setBigInt(res);
    return true;
}

const ClassSpec BigIntObject::classSpec_ = {
    GenericCreateConstructor<BigIntConstructor, 1, gc::AllocKind::FUNCTION>,
    CreateBigIntPrototype,
    BigIntObject::staticMethods,
    nullptr,
    BigIntObject::methods,
    BigIntObject::properties
};

const Class BigIntObject::class_ = {
    "BigInt",
    JSCLASS_HAS_CACHED_PROTO(JSProto_BigInt) |
    JSCLASS_HAS_RESERVED_SLOTS(RESERVED_SLOTS),
    JS_NULL_CLASS_OPS,
    &BigIntObject::classSpec_
};

const JSPropertySpec BigIntObject::properties[] = {
    // BigInt proposal section 5.3.5
    JS_STRING_SYM_PS(toStringTag, "BigInt", JSPROP_READONLY),
    JS_PS_END
};

const JSFunctionSpec BigIntObject::methods[] = {
    JS_FN("valueOf", valueOf, 0, 0),
    JS_FN("toString", toString, 0, 0),
    JS_SELF_HOSTED_FN("toLocaleString", "BigInt_toLocaleString", 0, 0),
    JS_FS_END
};

const JSFunctionSpec BigIntObject::staticMethods[] = {
    JS_FN("asUintN", asUintN, 2, 0),
    JS_FN("asIntN", asIntN, 2, 0),
    JS_FS_END
};