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;
}
static JSBool
DefineGetterOrSetter(JSContext *cx, uintN argc, JSBool wantGetter, jsval *vp)
{
uintN attrs;
JSBool found;
JSPropertyOp getter, setter;
JSObject *obj2;
jsval v;
jsid interned_id;
XPC_QS_ASSERT_CONTEXT_OK(cx);
JSObject *obj = JS_THIS_OBJECT(cx, vp);
if (!obj)
return JS_FALSE;
JSFastNative forward = wantGetter ? js_obj_defineGetter : js_obj_defineSetter;
jsval id = (argc >= 1) ? JS_ARGV(cx, vp)[0] : JSVAL_VOID;
if(!JSVAL_IS_STRING(id))
return forward(cx, argc, vp);
JSString *str = JSVAL_TO_STRING(id);
const char *name = JS_GetStringBytes(str);
if(!JS_ValueToId(cx, id, &interned_id) ||
!JS_LookupPropertyWithFlagsById(cx, obj, interned_id,
JSRESOLVE_QUALIFIED, &obj2, &v) ||
(obj2 &&
!JS_GetPropertyAttrsGetterAndSetterById(cx, obj2, interned_id, &attrs,
&found, &getter, &setter)))
return JS_FALSE;
// The property didn't exist, already has a getter or setter, or is not
// our property, then just forward now.
if(!obj2 ||
(attrs & (JSPROP_GETTER | JSPROP_SETTER)) ||
!(getter || setter) ||
!IS_PROTO_CLASS(STOBJ_GET_CLASS(obj2)))
return forward(cx, argc, vp);
// Reify the getter and setter...
if(!ReifyPropertyOps(cx, obj, id, interned_id, name, getter, setter,
nsnull, nsnull))
return JS_FALSE;
return forward(cx, argc, vp);
}
static JSBool
LookupGetterOrSetter(JSContext *cx, JSBool wantGetter, uintN argc, jsval *vp)
{
uintN attrs;
JSBool found;
JSPropertyOp getter, setter;
JSObject *obj2;
jsid interned_id;
jsval v;
XPC_QS_ASSERT_CONTEXT_OK(cx);
if(argc == 0)
{
JS_SET_RVAL(cx, vp, JSVAL_VOID);
return JS_TRUE;
}
JSObject *obj = JS_THIS_OBJECT(cx, vp);
if (!obj)
return JS_FALSE;
jsval idval = JS_ARGV(cx, vp)[0];
const char *name = JSVAL_IS_STRING(idval)
? JS_GetStringBytes(JSVAL_TO_STRING(idval))
: nsnull;
if(!JS_ValueToId(cx, idval, &interned_id) ||
!JS_LookupPropertyWithFlagsById(cx, obj, interned_id,
JSRESOLVE_QUALIFIED, &obj2, &v) ||
(obj2 &&
!JS_GetPropertyAttrsGetterAndSetterById(cx, obj2, interned_id, &attrs,
&found, &getter, &setter)))
return JS_FALSE;
// No property at all means no getters or setters possible.
if(!obj2 || !found)
{
JS_SET_RVAL(cx, vp, JSVAL_VOID);
return JS_TRUE;
}
// Inline obj_lookup[GS]etter here.
if(wantGetter)
{
if(attrs & JSPROP_GETTER)
{
JS_SET_RVAL(cx, vp,
OBJECT_TO_JSVAL(JS_FUNC_TO_DATA_PTR(JSObject *, getter)));
return JS_TRUE;
}
}
else
{
if(attrs & JSPROP_SETTER)
{
JS_SET_RVAL(cx, vp,
OBJECT_TO_JSVAL(JS_FUNC_TO_DATA_PTR(JSObject *, setter)));
return JS_TRUE;
}
}
// Since XPConnect doesn't use JSPropertyOps in any other contexts,
// ensuring that we have an XPConnect prototype object ensures that
// we are only going to expose quickstubbed properties to script.
// Also be careful not to overwrite existing properties!
if(!name ||
!IS_PROTO_CLASS(STOBJ_GET_CLASS(obj2)) ||
(attrs & (JSPROP_GETTER | JSPROP_SETTER)) ||
!(getter || setter))
{
JS_SET_RVAL(cx, vp, JSVAL_VOID);
return JS_TRUE;
}
JSObject *getterobj, *setterobj;
if(!ReifyPropertyOps(cx, obj, idval, interned_id, name, getter, setter,
&getterobj, &setterobj))
return JS_FALSE;
JSObject *wantedobj = wantGetter ? getterobj : setterobj;
v = wantedobj ? OBJECT_TO_JSVAL(wantedobj) : JSVAL_VOID;
JS_SET_RVAL(cx, vp, v);
return JS_TRUE;
}
