watch.mm

    __weak MyView *self_ = self;
    int const fdes = open([path fileSystemRepresentation], O_RDONLY);
    _fileWatcher = dispatch_source_create(DISPATCH_SOURCE_TYPE_VNODE, fdes,
                                          DISPATCH_VNODE_DELETE | DISPATCH_VNODE_WRITE,
                                          GlobalQueue);
    dispatch_source_set_event_handler(_fileWatcher, ^{
        unsigned long l = dispatch_source_get_data(_fileWatcher);
        if(l & DISPATCH_VNODE_DELETE || l & DISPATCH_VNODE_WRITE) {
            dispatch_source_cancel(_fileWatcher);
            NSLog(@"Reloading %@", path);
            AfterDelay(0.1, ^{
                self_.path = path;
            });
        }
    });
    dispatch_source_set_cancel_handler(_fileWatcher, ^{
        close(fdes);
    });
    dispatch_resume(_fileWatcher);