C++ HandleNativeObject类代码示例

bool
SetDenseElement(JSContext *cx, HandleNativeObject obj, int32_t index, HandleValue value,
                bool strict)
{
    // This function is called from Ion code for StoreElementHole's OOL path.
    // In this case we know the object is native and we can use setDenseElement
    // instead of setDenseElementWithType.

    NativeObject::EnsureDenseResult result = NativeObject::ED_SPARSE;
    do {
        if (index < 0)
            break;
        bool isArray = obj->is<ArrayObject>();
        if (isArray && !obj->as<ArrayObject>().lengthIsWritable())
            break;
        uint32_t idx = uint32_t(index);
        result = obj->ensureDenseElements(cx, idx, 1);
        if (result != NativeObject::ED_OK)
            break;
        if (isArray) {
            ArrayObject &arr = obj->as<ArrayObject>();
            if (idx >= arr.length())
                arr.setLengthInt32(idx + 1);
        }
        obj->setDenseElement(idx, value);
        return true;
    } while (false);

    if (result == NativeObject::ED_FAILED)
        return false;
    MOZ_ASSERT(result == NativeObject::ED_SPARSE);

    RootedValue indexVal(cx, Int32Value(index));
    return SetObjectElement(cx, obj, indexVal, value, strict);
}

static bool
CloneProperties(JSContext *cx, HandleNativeObject selfHostedObject, HandleObject clone)
{
    AutoIdVector ids(cx);

    for (size_t i = 0; i < selfHostedObject->getDenseInitializedLength(); i++) {
        if (!selfHostedObject->getDenseElement(i).isMagic(JS_ELEMENTS_HOLE)) {
            if (!ids.append(INT_TO_JSID(i)))
                return false;
        }
    }

    for (Shape::Range<NoGC> range(selfHostedObject->lastProperty()); !range.empty(); range.popFront()) {
        Shape &shape = range.front();
        if (shape.enumerable() && !ids.append(shape.propid()))
            return false;
    }

    RootedId id(cx);
    RootedValue val(cx);
    RootedValue selfHostedValue(cx);
    for (uint32_t i = 0; i < ids.length(); i++) {
        id = ids[i];
        if (!GetUnclonedValue(cx, selfHostedObject, id, &selfHostedValue))
            return false;
        if (!CloneValue(cx, selfHostedValue, &val) ||
            !JS_DefinePropertyById(cx, clone, id, val, 0))
        {
            return false;
        }
    }

    return true;
}

static inline void
AssertObjectPropertyFrozen(JSContext* cx, HandleNativeObject obj, uint32_t slot)
{
#ifdef DEBUG
    bool frozen = false;
    RootedObject property(cx, &obj->getSlot(slot).toObject());
    MOZ_ALWAYS_TRUE(TestIntegrityLevel(cx, property, IntegrityLevel::Frozen, &frozen));
    MOZ_ASSERT(frozen);
#endif
}

static bool
GetUnclonedValue(JSContext *cx, HandleNativeObject selfHostedObject,
                 HandleId id, MutableHandleValue vp)
{
    vp.setUndefined();

    if (JSID_IS_INT(id)) {
        size_t index = JSID_TO_INT(id);
        if (index < selfHostedObject->getDenseInitializedLength() &&
            !selfHostedObject->getDenseElement(index).isMagic(JS_ELEMENTS_HOLE))
        {
            vp.set(selfHostedObject->getDenseElement(JSID_TO_INT(id)));
            return true;
        }
    }

    // Since all atoms used by self hosting are marked as permanent, any
    // attempt to look up a non-permanent atom will fail. We should only
    // see such atoms when code is looking for properties on the self
    // hosted global which aren't present.
    if (JSID_IS_STRING(id) && !JSID_TO_STRING(id)->isPermanentAtom()) {
        MOZ_ASSERT(selfHostedObject->is<GlobalObject>());
        RootedValue value(cx, IdToValue(id));
        return js_ReportValueErrorFlags(cx, JSREPORT_ERROR, JSMSG_NO_SUCH_SELF_HOSTED_PROP,
                                        JSDVG_IGNORE_STACK, value, NullPtr(), nullptr, nullptr);
    }

    RootedShape shape(cx, selfHostedObject->lookupPure(id));
    if (!shape) {
        RootedValue value(cx, IdToValue(id));
        return js_ReportValueErrorFlags(cx, JSREPORT_ERROR, JSMSG_NO_SUCH_SELF_HOSTED_PROP,
                                        JSDVG_IGNORE_STACK, value, NullPtr(), nullptr, nullptr);
    }

    MOZ_ASSERT(shape->hasSlot() && shape->hasDefaultGetter());
    vp.set(selfHostedObject->getSlot(shape->slot()));
    return true;
}

static bool
EnumerateNativeProperties(JSContext* cx, HandleNativeObject pobj, unsigned flags, Maybe<IdSet>& ht,
                          AutoIdVector* props)
{
    bool enumerateSymbols;
    if (flags & JSITER_SYMBOLSONLY) {
        enumerateSymbols = true;
    } else {
        /* Collect any dense elements from this object. */
        size_t initlen = pobj->getDenseInitializedLength();
        const Value* vp = pobj->getDenseElements();
        for (size_t i = 0; i < initlen; ++i, ++vp) {
            if (!vp->isMagic(JS_ELEMENTS_HOLE)) {
                /* Dense arrays never get so large that i would not fit into an integer id. */
                if (!Enumerate(cx, pobj, INT_TO_JSID(i), /* enumerable = */ true, flags, ht, props))
                    return false;
            }
        }

        /* Collect any typed array or shared typed array elements from this object. */
        if (IsAnyTypedArray(pobj)) {
            size_t len = AnyTypedArrayLength(pobj);
            for (size_t i = 0; i < len; i++) {
                if (!Enumerate(cx, pobj, INT_TO_JSID(i), /* enumerable = */ true, flags, ht, props))
                    return false;
            }
        }

        size_t initialLength = props->length();

        /* Collect all unique property names from this object's shape. */
        bool symbolsFound = false;
        Shape::Range<NoGC> r(pobj->lastProperty());
        for (; !r.empty(); r.popFront()) {
            Shape& shape = r.front();
            jsid id = shape.propid();

            if (JSID_IS_SYMBOL(id)) {
                symbolsFound = true;
                continue;
            }

            if (!Enumerate(cx, pobj, id, shape.enumerable(), flags, ht, props))
                return false;
        }
        ::Reverse(props->begin() + initialLength, props->end());

        enumerateSymbols = symbolsFound && (flags & JSITER_SYMBOLS);
    }

    if (enumerateSymbols) {
        // Do a second pass to collect symbols. ES6 draft rev 25 (2014 May 22)
        // 9.1.12 requires that all symbols appear after all strings in the
        // result.
        size_t initialLength = props->length();
        for (Shape::Range<NoGC> r(pobj->lastProperty()); !r.empty(); r.popFront()) {
            Shape& shape = r.front();
            jsid id = shape.propid();
            if (JSID_IS_SYMBOL(id)) {
                if (!Enumerate(cx, pobj, id, shape.enumerable(), flags, ht, props))
                    return false;
            }
        }
        ::Reverse(props->begin() + initialLength, props->end());
    }

    return true;
}

static bool
EnumerateNativeProperties(JSContext* cx, HandleNativeObject pobj, unsigned flags, Maybe<IdSet>& ht,
                          AutoIdVector* props, Handle<UnboxedPlainObject*> unboxed = nullptr)
{
    bool enumerateSymbols;
    if (flags & JSITER_SYMBOLSONLY) {
        enumerateSymbols = true;
    } else {
        /* Collect any dense elements from this object. */
        size_t firstElemIndex = props->length();
        size_t initlen = pobj->getDenseInitializedLength();
        const Value* vp = pobj->getDenseElements();
        bool hasHoles = false;
        for (size_t i = 0; i < initlen; ++i, ++vp) {
            if (vp->isMagic(JS_ELEMENTS_HOLE)) {
                hasHoles = true;
            } else {
                /* Dense arrays never get so large that i would not fit into an integer id. */
                if (!Enumerate(cx, pobj, INT_TO_JSID(i), /* enumerable = */ true, flags, ht, props))
                    return false;
            }
        }

        /* Collect any typed array or shared typed array elements from this object. */
        if (pobj->is<TypedArrayObject>()) {
            size_t len = pobj->as<TypedArrayObject>().length();
            for (size_t i = 0; i < len; i++) {
                if (!Enumerate(cx, pobj, INT_TO_JSID(i), /* enumerable = */ true, flags, ht, props))
                    return false;
            }
        }

        // Collect any sparse elements from this object.
        bool isIndexed = pobj->isIndexed();
        if (isIndexed) {
            // If the dense elements didn't have holes, we don't need to include
            // them in the sort.
            if (!hasHoles)
                firstElemIndex = props->length();

            for (Shape::Range<NoGC> r(pobj->lastProperty()); !r.empty(); r.popFront()) {
                Shape& shape = r.front();
                jsid id = shape.propid();
                uint32_t dummy;
                if (IdIsIndex(id, &dummy)) {
                    if (!Enumerate(cx, pobj, id, shape.enumerable(), flags, ht, props))
                        return false;
                }
            }

            MOZ_ASSERT(firstElemIndex <= props->length());

            jsid* ids = props->begin() + firstElemIndex;
            size_t n = props->length() - firstElemIndex;

            AutoIdVector tmp(cx);
            if (!tmp.resize(n))
                return false;
            PodCopy(tmp.begin(), ids, n);

            if (!MergeSort(ids, n, tmp.begin(), SortComparatorIntegerIds))
                return false;
        }

        if (unboxed) {
            // If |unboxed| is set then |pobj| is the expando for an unboxed
            // plain object we are enumerating. Add the unboxed properties
            // themselves here since they are all property names that were
            // given to the object before any of the expando's properties.
            MOZ_ASSERT(pobj->is<UnboxedExpandoObject>());
            if (!EnumerateExtraProperties(cx, unboxed, flags, ht, props))
                return false;
        }

        size_t initialLength = props->length();

        /* Collect all unique property names from this object's shape. */
        bool symbolsFound = false;
        Shape::Range<NoGC> r(pobj->lastProperty());
        for (; !r.empty(); r.popFront()) {
            Shape& shape = r.front();
            jsid id = shape.propid();

            if (JSID_IS_SYMBOL(id)) {
                symbolsFound = true;
                continue;
            }

            uint32_t dummy;
            if (isIndexed && IdIsIndex(id, &dummy))
                continue;

            if (!Enumerate(cx, pobj, id, shape.enumerable(), flags, ht, props))
                return false;
        }
        ::Reverse(props->begin() + initialLength, props->end());

        enumerateSymbols = symbolsFound && (flags & JSITER_SYMBOLS);
    }

//.........这里部分代码省略.........

static bool
FreezeObjectProperty(JSContext* cx, HandleNativeObject obj, uint32_t slot)
{
    RootedObject property(cx, &obj->getSlot(slot).toObject());
    return FreezeObject(cx, property);
}

static inline bool
IsObjectPropertyFrozen(JSContext* cx, HandleNativeObject obj, uint32_t slot)
{
    RootedObject property(cx, &obj->getSlot(slot).toObject());
    return IsObjectFrozen(cx, property);
}