"""Thread-safe hash set.

Ported from net.i2p.util.ConcurrentHashSet.
"""

from __future__ import annotations

import threading
from typing import Iterator


class ConcurrentHashSet:
    """Thread-safe set wrapper."""

    def __init__(self) -> None:
        self._lock = threading.Lock()
        self._data: set = set()

    def add(self, item) -> None:
        with self._lock:
            self._data.add(item)

    def remove(self, item) -> None:
        with self._lock:
            self._data.remove(item)

    def discard(self, item) -> None:
        with self._lock:
            self._data.discard(item)

    def __contains__(self, item) -> bool:
        with self._lock:
            return item in self._data

    def __len__(self) -> int:
        with self._lock:
            return len(self._data)

    def __iter__(self) -> Iterator:
        with self._lock:
            return iter(list(self._data))