77 lines
3.0 KiB
Python
77 lines
3.0 KiB
Python
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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"""
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轻量级事件总线
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支持 subscribe(event_name, callback)、unsubscribe(event_name, callback)
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和 publish(event_name, data)，用于步骤面板间的去中心化参数传导。
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2026-06-30 修复：
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- publish() 中的 except Exception: pass 改为 traceback 日志输出（静默吞异常会导致 bug 无法发现）
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- 新增 unsubscribe() 方法，允许面板销毁时清理订阅，防止内存泄漏和野指针回调
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"""
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import sys
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import threading
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import traceback
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from collections import defaultdict
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from typing import Any, Callable, Dict, List, Optional
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class EventBus:
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"""发布-订阅事件总线（线程安全）。"""
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def __init__(self):
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self._subscribers: Dict[str, List[Callable]] = defaultdict(list)
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self._lock = threading.Lock()
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# 异常日志回调（可选注入，供 LogManager 使用）
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self._error_logger: Optional[Callable[[str], None]] = None
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def set_error_logger(self, logger: Callable[[str], None]):
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"""注入异常日志回调。若不设置，异常信息输出到 stderr。"""
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self._error_logger = logger
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def subscribe(self, event_name: str, callback: Callable[[dict], None]):
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"""订阅事件。callback 接收一个 dict 作为事件数据。"""
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with self._lock:
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if callback not in self._subscribers[event_name]:
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self._subscribers[event_name].append(callback)
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def unsubscribe(self, event_name: str, callback: Callable[[dict], None]):
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"""取消订阅。面板销毁或不再需要接收事件时调用，防止野指针回调。"""
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with self._lock:
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subs = self._subscribers.get(event_name)
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if subs and callback in subs:
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subs.remove(callback)
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# 清理空列表，避免字典膨胀
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if not subs:
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del self._subscribers[event_name]
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def publish(self, event_name: str, data: Dict[str, Any]):
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"""发布事件，通知所有订阅者。订阅者异常不再静默吞掉，而是输出 traceback。
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迭代订阅者列表的副本，防止回调中调用 unsubscribe() 导致跳过后续订阅者。
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"""
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with self._lock:
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snapshot = list(self._subscribers.get(event_name, []))
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for callback in snapshot:
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try:
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callback(data)
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except Exception:
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cb_name = getattr(callback, '__name__', None) or repr(callback)
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err_msg = (
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f"[EventBus] 事件 '{event_name}' 的订阅者 {cb_name!r} 抛出异常:\n"
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+ traceback.format_exc()
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)
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if self._error_logger:
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try:
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self._error_logger(err_msg)
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except Exception:
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print(err_msg, file=sys.stderr, flush=True)
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else:
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print(err_msg, file=sys.stderr, flush=True)
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# 全局单例
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global_event_bus = EventBus()
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