Method next

crates/test-programs/src/bin/p1_fd_readdir.rs:28–54

(&mut self)

    type Item = DirEntry;

    fn next(&mut self) -> Option<DirEntry> {
        unsafe {
            if self.buf.len() < mem::size_of::<wasip1::Dirent>() {
                return None;
            }

            // Read the data
            let dirent_ptr = self.buf.as_ptr() as *const wasip1::Dirent;
            let dirent = dirent_ptr.read_unaligned();

            if self.buf.len() < mem::size_of::<wasip1::Dirent>() + dirent.d_namlen as usize {
                return None;
            }

            let name_ptr = dirent_ptr.offset(1) as *const u8;
            // NOTE Linux syscall returns a NUL-terminated name, but WASI doesn't
            let namelen = dirent.d_namlen as usize;
            let slice = slice::from_raw_parts(name_ptr, namelen);
            let name = str::from_utf8(slice).expect("invalid utf8").to_owned();

            // Update the internal state
            let delta = mem::size_of_val(&dirent) + namelen;
            self.buf = &self.buf[delta..];

            DirEntry { dirent, name }.into()
        }
    }
}

/// Return the entries plus a bool indicating EOF.