bool
XPC_WN_GetterSetter(JSContext* cx, unsigned argc, Value* vp)
{
JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
MOZ_ASSERT(JS_TypeOfValue(cx, args.calleev()) == JSTYPE_FUNCTION, "bad function");
RootedObject funobj(cx, &args.callee());
RootedObject obj(cx, JS_THIS_OBJECT(cx, vp));
if (!obj)
return false;
obj = FixUpThisIfBroken(obj, funobj);
XPCCallContext ccx(cx, obj, funobj, JSID_VOIDHANDLE, args.length(),
args.array(), vp);
XPCWrappedNative* wrapper = ccx.GetWrapper();
THROW_AND_RETURN_IF_BAD_WRAPPER(cx, wrapper);
RefPtr<XPCNativeInterface> iface;
XPCNativeMember* member;
if (!XPCNativeMember::GetCallInfo(funobj, &iface, &member))
return Throw(NS_ERROR_XPC_CANT_GET_METHOD_INFO, cx);
if (args.length() != 0 && member->IsWritableAttribute()) {
ccx.SetCallInfo(iface, member, true);
bool retval = XPCWrappedNative::SetAttribute(ccx);
if (retval)
args.rval().set(args[0]);
return retval;
}
// else...
ccx.SetCallInfo(iface, member, false);
return XPCWrappedNative::GetAttribute(ccx);
}
XPCWrappedNative*
XPCCallContext::UnwrapThisIfAllowed(HandleObject obj, HandleObject fun, unsigned argc)
{
// We should only get here for objects that aren't safe to unwrap.
MOZ_ASSERT(!js::CheckedUnwrap(obj));
MOZ_ASSERT(js::IsObjectInContextCompartment(obj, mJSContext));
// We can't do anything here without a function.
if (!fun)
return nullptr;
// Determine if we're allowed to unwrap the security wrapper to invoke the
// method.
//
// We have the Interface and Member that this corresponds to, but
// unfortunately our access checks are based on the object class name and
// property name. So we cheat a little bit here - we verify that the object
// does indeed implement the method's Interface, and then just check that we
// can successfully access property with method's name from the object.
// First, get the XPCWN out of the underlying object. We should have a wrapper
// here, potentially an outer window proxy, and then an XPCWN.
MOZ_ASSERT(js::IsWrapper(obj));
RootedObject unwrapped(mJSContext, js::UncheckedUnwrap(obj, /* stopAtOuter = */ false));
#ifdef DEBUG
JS::Rooted<JSObject*> wrappedObj(mJSContext, js::Wrapper::wrappedObject(obj));
MOZ_ASSERT(unwrapped == JS_ObjectToInnerObject(mJSContext, wrappedObj));
#endif
// Make sure we have an XPCWN, and grab it.
if (!IS_WN_REFLECTOR(unwrapped))
return nullptr;
XPCWrappedNative *wn = XPCWrappedNative::Get(unwrapped);
// Next, get the call info off the function object.
XPCNativeInterface *interface;
XPCNativeMember *member;
XPCNativeMember::GetCallInfo(fun, &interface, &member);
// To be extra safe, make sure that the underlying native implements the
// interface before unwrapping. Even if we didn't check this, we'd still
// theoretically fail during tearoff lookup for mismatched methods.
if (!wn->HasInterfaceNoQI(*interface->GetIID()))
return nullptr;
// See if the access is permitted.
//
// NB: This calculation of SET vs GET is a bit wonky, but that's what
// XPC_WN_GetterSetter does.
bool set = argc && argc != NO_ARGS && member->IsWritableAttribute();
js::Wrapper::Action act = set ? js::Wrapper::SET : js::Wrapper::GET;
const js::Wrapper *handler = js::Wrapper::wrapperHandler(obj);
bool ignored;
JS::Rooted<jsid> id(mJSContext, member->GetName());
if (!handler->enter(mJSContext, obj, id, act, &ignored))
return nullptr;
// Ok, this call is safe.
return wn;
}
static bool
ResolveNativeProperty(JSContext *cx, JSObject *wrapper, JSObject *holder, jsid id, bool set,
JSPropertyDescriptor *desc)
{
desc->obj = NULL;
NS_ASSERTION(holder->getJSClass() == &HolderClass, "expected a native property holder object");
JSObject *wnObject = GetWrappedNativeObjectFromHolder(holder);
XPCWrappedNative *wn = GetWrappedNative(wnObject);
// This will do verification and the method lookup for us.
XPCCallContext ccx(JS_CALLER, cx, wnObject, nsnull, id);
// There are no native numeric properties, so we can shortcut here. We will not
// find the property.
if (!JSID_IS_ATOM(id)) {
/* Not found */
return true;
}
XPCNativeInterface *iface;
XPCNativeMember *member;
if (ccx.GetWrapper() != wn ||
!wn->IsValid() ||
!(iface = ccx.GetInterface()) ||
!(member = ccx.GetMember())) {
/* Not found */
return true;
}
desc->obj = holder;
desc->attrs = JSPROP_ENUMERATE;
desc->getter = NULL;
desc->setter = NULL;
desc->shortid = 0;
desc->value = JSVAL_VOID;
jsval fval = JSVAL_VOID;
if (member->IsConstant()) {
if (!member->GetConstantValue(ccx, iface, &desc->value)) {
JS_ReportError(cx, "Failed to convert constant native property to JS value");
return false;
}
} else if (member->IsAttribute()) {
// This is a getter/setter. Clone a function for it.
if (!member->NewFunctionObject(ccx, iface, wrapper, &fval)) {
JS_ReportError(cx, "Failed to clone function object for native getter/setter");
return false;
}
desc->attrs |= JSPROP_GETTER;
if (member->IsWritableAttribute())
desc->attrs |= JSPROP_SETTER;
// Make the property shared on the holder so no slot is allocated
// for it. This avoids keeping garbage alive through that slot.
desc->attrs |= JSPROP_SHARED;
} else {
// This is a method. Clone a function for it.
if (!member->NewFunctionObject(ccx, iface, wrapper, &desc->value)) {
JS_ReportError(cx, "Failed to clone function object for native function");
return false;
}
// Without a wrapper the function would live on the prototype. Since we
// don't have one, we have to avoid calling the scriptable helper's
// GetProperty method for this property, so stub out the getter and
// setter here explicitly.
desc->getter = JS_PropertyStub;
desc->setter = JS_StrictPropertyStub;
}
if (!JS_WrapValue(cx, &desc->value) || !JS_WrapValue(cx, &fval))
return false;
if (desc->attrs & JSPROP_GETTER)
desc->getter = CastAsJSPropertyOp(JSVAL_TO_OBJECT(fval));
if (desc->attrs & JSPROP_SETTER)
desc->setter = CastAsJSStrictPropertyOp(JSVAL_TO_OBJECT(fval));
// Define the property.
return JS_DefinePropertyById(cx, holder, id, desc->value,
desc->getter, desc->setter, desc->attrs);
}
