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
InterposeCall(JSContext* cx, JS::HandleObject target, const JS::CallArgs& args, bool* done)
{
*done = false;
XPCWrappedNativeScope* scope = ObjectScope(CurrentGlobalOrNull(cx));
MOZ_ASSERT(scope->HasInterposition());
nsCOMPtr<nsIAddonInterposition> interp = scope->GetInterposition();
RootedObject unwrappedTarget(cx, UncheckedUnwrap(target));
XPCWrappedNativeScope* targetScope = ObjectScope(unwrappedTarget);
bool hasInterpostion = targetScope->HasCallInterposition();
if (!hasInterpostion)
return true;
// If there is a call interpostion, we don't want to propogate the
// call to Base:
*done = true;
JSAddonId* addonId = AddonIdOfObject(target);
RootedValue addonIdValue(cx, StringValue(StringOfAddonId(addonId)));
RootedValue targetValue(cx, ObjectValue(*target));
RootedValue thisValue(cx, args.thisv());
RootedObject argsArray(cx, ConvertArgsToArray(cx, args));
if (!argsArray)
return false;
RootedValue argsVal(cx, ObjectValue(*argsArray));
RootedValue returnVal(cx);
nsresult rv = interp->InterposeCall(addonIdValue, targetValue,
thisValue, argsVal, args.rval());
if (NS_FAILED(rv)) {
xpc::Throw(cx, rv);
return false;
}
return true;
}