Function exception_to_string

gjs/jsapi-util.cpp:232–247

Helper function: perform ToString on an exception (which may not even be an object), except if it is an InternalError, which would throw in ToString.

// Helper function: perform ToString on an exception (which may not even be an
// object), except if it is an InternalError, which would throw in ToString.
GJS_JSAPI_RETURN_CONVENTION
static JSString* exception_to_string(JSContext* cx, JS::HandleValue exc) {
    if (exc.isObject()) {
        JS::RootedObject exc_obj(cx, &exc.toObject());
        const JSClass* internal_error =
            js::ProtoKeyToClass(JSProto_InternalError);
        if (JS_InstanceOf(cx, exc_obj, internal_error, nullptr)) {
            JSErrorReport* report = JS_ErrorFromException(cx, exc_obj);
            if (!report->message())
                return JS_NewStringCopyZ(cx, "(unknown internal error)");
            return JS_NewStringCopyUTF8Z(cx, report->message());
        }
    }

    return JS::ToString(cx, exc);
}

// Helper function: log and clear the pending exception, without calling into
// any JS APIs that might cause more exceptions to be thrown.