Function clear_snapshot_buffer

refs/packed-backend.c:180–191

* If the buffer in `snapshot` is active, then either munmap the * memory and close the file, or free the memory. Then set the buffer * pointers to NULL. */

 * pointers to NULL.
 */
static void clear_snapshot_buffer(struct snapshot *snapshot)
{
	if (snapshot->mmapped) {
		if (munmap(snapshot->buf, snapshot->eof - snapshot->buf))
			die_errno("error ummapping packed-refs file %s",
				  snapshot->refs->path);
		snapshot->mmapped = 0;
	} else {
		free(snapshot->buf);
	}
	snapshot->buf = snapshot->start = snapshot->eof = NULL;
}

/*
 * Decrease the reference count of `*snapshot`. If it goes to zero,