/*[clinic input]
os.scandir

    path : path_t(nullable=True, allow_fd='PATH_HAVE_FDOPENDIR') = None

Return an iterator of DirEntry objects for given path.

path can be specified as either str, bytes, or a path-like object.  If path
is bytes, the names of yielded DirEntry objects will also be bytes; in
all other circumstances they will be str.

If path is None, uses the path='.'.
[clinic start generated code]*/

static PyObject *
os_scandir_impl(PyObject *module, path_t *path)
/*[clinic end generated code: output=6eb2668b675ca89e input=6bdd312708fc3bb0]*/
{
    ScandirIterator *iterator;
#ifdef MS_WINDOWS
    wchar_t *path_strW;
#else
    const char *path_str;
#ifdef HAVE_FDOPENDIR
    int fd = -1;
#endif
#endif

    if (PySys_Audit("os.scandir", "O",
                    path->object ? path->object : Py_None) < 0) {
        return NULL;
    }

    PyObject *ScandirIteratorType = get_posix_state(module)->ScandirIteratorType;
    iterator = PyObject_New(ScandirIterator, (PyTypeObject *)ScandirIteratorType);
    if (!iterator)
        return NULL;

#ifdef MS_WINDOWS
    iterator->handle = INVALID_HANDLE_VALUE;
#else
    iterator->dirp = NULL;
#endif

    memcpy(&iterator->path, path, sizeof(path_t));
    /* Move the ownership to iterator->path */
    path->object = NULL;
    path->cleanup = NULL;

#ifdef MS_WINDOWS
    iterator->first_time = 1;

    path_strW = join_path_filenameW(iterator->path.wide, L"*.*");
    if (!path_strW)
        goto error;

    Py_BEGIN_ALLOW_THREADS
    iterator->handle = FindFirstFileW(path_strW, &iterator->file_data);
    Py_END_ALLOW_THREADS

    PyMem_Free(path_strW);

    if (iterator->handle == INVALID_HANDLE_VALUE) {
        path_error(&iterator->path);
        goto error;
    }
#else /* POSIX */
    errno = 0;
#ifdef HAVE_FDOPENDIR
    if (path->fd != -1) {
        /* closedir() closes the FD, so we duplicate it */
        fd = _Py_dup(path->fd);
        if (fd == -1)
            goto error;

        Py_BEGIN_ALLOW_THREADS
        iterator->dirp = fdopendir(fd);
        Py_END_ALLOW_THREADS
    }
    else
#endif
    {
        if (iterator->path.narrow)
            path_str = iterator->path.narrow;
        else
            path_str = ".";

        Py_BEGIN_ALLOW_THREADS
        iterator->dirp = opendir(path_str);
        Py_END_ALLOW_THREADS
    }

    if (!iterator->dirp) {
        path_error(&iterator->path);
#ifdef HAVE_FDOPENDIR
        if (fd != -1) {
            Py_BEGIN_ALLOW_THREADS
            close(fd);
            Py_END_ALLOW_THREADS
        }
#endif
        goto error;
    }
#endif

    return (PyObject *)iterator;

error:
    Py_DECREF(iterator);
    return NULL;
}