C++ MutableHandle类代码示例

bool
BaseDOMProxyHandler::getPropertyDescriptor(JSContext* cx,
                                           JS::Handle<JSObject*> proxy,
                                           JS::Handle<jsid> id,
                                           MutableHandle<JSPropertyDescriptor> desc,
                                           unsigned flags)
{
  if (!getOwnPropertyDescriptor(cx, proxy, id, desc, flags)) {
    return false;
  }
  if (desc.object()) {
    return true;
  }

  JS::Rooted<JSObject*> proto(cx);
  if (!js::GetObjectProto(cx, proxy, &proto)) {
    return false;
  }
  if (!proto) {
    desc.object().set(nullptr);
    return true;
  }

  return JS_GetPropertyDescriptorById(cx, proto, id, 0, desc);
}

bool
SavedStacks::insertFrames(JSContext *cx, ScriptFrameIter &iter, MutableHandle<SavedFrame*> frame)
{
    if (iter.done()) {
        frame.set(nullptr);
        return true;
    }

    ScriptFrameIter thisFrame(iter);
    Rooted<SavedFrame*> parentFrame(cx);
    if (!insertFrames(cx, ++iter, &parentFrame))
        return false;

    RootedScript script(cx, thisFrame.script());
    RootedFunction callee(cx, thisFrame.maybeCallee());
    const char *filename = script->filename();
    RootedAtom source(cx, Atomize(cx, filename, strlen(filename)));
    if (!source)
        return false;
    uint32_t column;
    uint32_t line = PCToLineNumber(script, thisFrame.pc(), &column);

    SavedFrame::Lookup lookup(source,
                              line,
                              column,
                              callee ? callee->displayAtom() : nullptr,
                              parentFrame,
                              thisFrame.compartment()->principals);

    frame.set(getOrCreateSavedFrame(cx, lookup));
    return frame.address() != nullptr;
}

bool
JSCompartment::wrap(JSContext *cx, MutableHandle<PropDesc> desc)
{
    if (desc.isUndefined())
        return true;

    JSCompartment *comp = cx->compartment();

    if (desc.hasValue()) {
        RootedValue value(cx, desc.value());
        if (!comp->wrap(cx, &value))
            return false;
        desc.setValue(value);
    }
    if (desc.hasGet()) {
        RootedValue get(cx, desc.getterValue());
        if (!comp->wrap(cx, &get))
            return false;
        desc.setGetter(get);
    }
    if (desc.hasSet()) {
        RootedValue set(cx, desc.setterValue());
        if (!comp->wrap(cx, &set))
            return false;
        desc.setSetter(set);
    }
    return true;
}

bool
InterposeProperty(JSContext* cx, HandleObject target, const nsIID* iid, HandleId id,
                  MutableHandle<JSPropertyDescriptor> descriptor)
{
    // We only want to do interpostion on DOM instances and
    // wrapped natives.
    RootedObject unwrapped(cx, UncheckedUnwrap(target));
    const js::Class* clasp = js::GetObjectClass(unwrapped);
    if (!mozilla::dom::IsDOMClass(clasp) &&
        !IS_WN_CLASS(clasp) &&
        !IS_PROTO_CLASS(clasp) &&
        clasp != &OuterWindowProxyClass) {
        return true;
    }

    XPCWrappedNativeScope* scope = ObjectScope(CurrentGlobalOrNull(cx));
    MOZ_ASSERT(scope->HasInterposition());

    nsCOMPtr<nsIAddonInterposition> interp = scope->GetInterposition();
    JSAddonId* addonId = AddonIdOfObject(target);
    RootedValue addonIdValue(cx, StringValue(StringOfAddonId(addonId)));
    RootedValue prop(cx, IdToValue(id));
    RootedValue targetValue(cx, ObjectValue(*target));
    RootedValue descriptorVal(cx);
    nsresult rv = interp->InterposeProperty(addonIdValue, targetValue,
                                            iid, prop, &descriptorVal);
    if (NS_FAILED(rv)) {
        xpc::Throw(cx, rv);
        return false;
    }

    if (!descriptorVal.isObject())
        return true;

    // We need to be careful parsing descriptorVal. |cx| is in the compartment
    // of the add-on and the descriptor is in the compartment of the
    // interposition. We could wrap the descriptor in the add-on's compartment
    // and then parse it. However, parsing the descriptor fetches properties
    // from it, and we would try to interpose on those property accesses. So
    // instead we parse in the interposition's compartment and then wrap the
    // descriptor.

    {
        JSAutoCompartment ac(cx, &descriptorVal.toObject());
        if (!JS::ObjectToCompletePropertyDescriptor(cx, target, descriptorVal, descriptor))
            return false;
    }

    // Always make the property non-configurable regardless of what the
    // interposition wants.
    descriptor.setAttributes(descriptor.attributes() | JSPROP_PERMANENT);

    if (!JS_WrapPropertyDescriptor(cx, descriptor))
        return false;

    return true;
}

bool
JavaScriptShared::toDescriptor(JSContext* cx, const PPropertyDescriptor& in,
                               MutableHandle<JSPropertyDescriptor> out)
{
    out.setAttributes(in.attrs());
    if (!fromVariant(cx, in.value(), out.value()))
        return false;
    out.object().set(fromObjectOrNullVariant(cx, in.obj()));

    if (in.getter().type() == GetterSetter::Tuint64_t && !in.getter().get_uint64_t()) {
        out.setGetter(nullptr);
    } else if (in.attrs() & JSPROP_GETTER) {
        Rooted<JSObject*> getter(cx);
        getter = fromObjectVariant(cx, in.getter().get_ObjectVariant());
        if (!getter)
            return false;
        out.setGetter(JS_DATA_TO_FUNC_PTR(JSGetterOp, getter.get()));
    } else {
        out.setGetter(UnknownPropertyStub);
    }

    if (in.setter().type() == GetterSetter::Tuint64_t && !in.setter().get_uint64_t()) {
        out.setSetter(nullptr);
    } else if (in.attrs() & JSPROP_SETTER) {
        Rooted<JSObject*> setter(cx);
        setter = fromObjectVariant(cx, in.setter().get_ObjectVariant());
        if (!setter)
            return false;
        out.setSetter(JS_DATA_TO_FUNC_PTR(JSSetterOp, setter.get()));
    } else {
        out.setSetter(UnknownStrictPropertyStub);
    }

    return true;
}

static bool
GetSharedTypedArray(JSContext* cx, HandleValue v,
                    MutableHandle<TypedArrayObject*> viewp)
{
    if (!v.isObject())
        return ReportBadArrayType(cx);
    if (!v.toObject().is<TypedArrayObject>())
        return ReportBadArrayType(cx);
    viewp.set(&v.toObject().as<TypedArrayObject>());
    if (!viewp->isSharedMemory())
        return ReportBadArrayType(cx);
    return true;
}

bool
SecurityWrapper<Base>::defineProperty(JSContext *cx, HandleObject wrapper,
                                      HandleId id, MutableHandle<PropertyDescriptor> desc)
{
    if (desc.getter() || desc.setter()) {
        JSString *str = IdToString(cx, id);
        const jschar *prop = str ? str->getCharsZ(cx) : nullptr;
        JS_ReportErrorNumberUC(cx, js_GetErrorMessage, nullptr,
                               JSMSG_ACCESSOR_DEF_DENIED, prop);
        return false;
    }

    return Base::defineProperty(cx, wrapper, id, desc);
}

static bool
CloneModule(JSContext* cx, MutableHandle<AsmJSModuleObject*> moduleObj)
{
    ScopedJSDeletePtr<AsmJSModule> module;
    if (!moduleObj->module().clone(cx, &module))
        return false;

    AsmJSModuleObject* newModuleObj = AsmJSModuleObject::create(cx, &module);
    if (!newModuleObj)
        return false;

    moduleObj.set(newModuleObj);
    return true;
}

bool
BaselineFrame::copyRawFrameSlots(MutableHandle<GCVector<Value>> vec) const
{
    unsigned nfixed = script()->nfixed();
    unsigned nformals = numFormalArgs();

    if (!vec.resize(nformals + nfixed))
        return false;

    mozilla::PodCopy(vec.begin(), argv(), nformals);
    for (unsigned i = 0; i < nfixed; i++)
        vec[nformals + i].set(*valueSlot(i));
    return true;
}

bool
WaiveXrayWrapper::getOwnPropertyDescriptor(JSContext* cx, HandleObject wrapper, HandleId id,
                                           MutableHandle<PropertyDescriptor> desc) const
{
    return CrossCompartmentWrapper::getOwnPropertyDescriptor(cx, wrapper, id, desc) &&
           WrapperFactory::WaiveXrayAndWrap(cx, desc.value()) && WaiveAccessors(cx, desc);
}

static bool
FillVector(JSContext* cx, MutableHandle<ShapeVec> shapes)
{
    for (size_t i = 0; i < 10; ++i) {
        RootedObject obj(cx, JS_NewObject(cx, nullptr));
        RootedValue val(cx, UndefinedValue());
        // Construct a unique property name to ensure that the object creates a
        // new shape.
        char buffer[2];
        buffer[0] = 'a' + i;
        buffer[1] = '\0';
        if (!JS_SetProperty(cx, obj, buffer, val))
            return false;
        if (!shapes.append(obj->as<NativeObject>().lastProperty()))
            return false;
    }

    // Ensure iterator enumeration works through the mutable handle.
    for (auto shape : shapes) {
        if (!shape)
            return false;
    }

    return true;
}

static bool
ImportFunctions(JSContext* cx, HandleObject importObj, const ImportNameVector& importNames,
                MutableHandle<FunctionVector> imports)
{
    if (!importNames.empty() && !importObj)
        return Fail(cx, "no import object given");

    for (const ImportName& name : importNames) {
        RootedValue v(cx);
        if (!GetProperty(cx, importObj, name.module.get(), &v))
            return false;

        if (*name.func.get()) {
            if (!v.isObject())
                return Fail(cx, "import object field is not an Object");

            RootedObject obj(cx, &v.toObject());
            if (!GetProperty(cx, obj, name.func.get(), &v))
                return false;
        }

        if (!IsFunctionObject(v))
            return Fail(cx, "import object field is not a Function");

        if (!imports.append(&v.toObject().as<JSFunction>()))
            return false;
    }

    return true;
}

bool
js::XDRScriptRegExpObject(XDRState<mode>* xdr, MutableHandle<RegExpObject*> objp)
{
    /* NB: Keep this in sync with CloneScriptRegExpObject. */

    RootedAtom source(xdr->cx());
    uint32_t flagsword = 0;

    if (mode == XDR_ENCODE) {
        MOZ_ASSERT(objp);
        RegExpObject& reobj = *objp;
        source = reobj.getSource();
        flagsword = reobj.getFlags();
    }
    if (!XDRAtom(xdr, &source) || !xdr->codeUint32(&flagsword))
        return false;
    if (mode == XDR_DECODE) {
        RegExpFlag flags = RegExpFlag(flagsword);
        RegExpObject* reobj = RegExpObject::createNoStatics(xdr->cx(), source, flags, nullptr,
                                                            xdr->cx()->tempLifoAlloc());
        if (!reobj)
            return false;

        objp.set(reobj);
    }
    return true;
}

bool
SecurityWrapper<Base>::defineProperty(JSContext *cx, HandleObject wrapper,
                                      HandleId id, MutableHandle<PropertyDescriptor> desc) const
{
    if (desc.getter() || desc.setter()) {
        JSString *str = IdToString(cx, id);
        AutoStableStringChars chars(cx);
        const jschar *prop = nullptr;
        if (str->ensureFlat(cx) && chars.initTwoByte(cx, str))
            prop = chars.twoByteChars();
        JS_ReportErrorNumberUC(cx, js_GetErrorMessage, nullptr,
                               JSMSG_ACCESSOR_DEF_DENIED, prop);
        return false;
    }

    return Base::defineProperty(cx, wrapper, id, desc);
}

static bool
proxy_LookupProperty(JSContext* cx, HandleObject obj, HandleId id,
                     MutableHandleObject objp, MutableHandle<JS::PropertyResult> propp)
{
    bool found;
    if (!Proxy::has(cx, obj, id, &found))
        return false;

    if (found) {
        propp.setNonNativeProperty();
        objp.set(obj);
    } else {
        propp.setNotFound();
        objp.set(nullptr);
    }
    return true;
}