may fix #49

README.md

@@ -174,6 +174,10 @@ Telegram：[@lgc2333](https://t.me/lgc2333)
 
 ## 📝 更新日志
 
+### 2.1.2
+
+- fix [#49](https://github.com/lgc-NB2Dev/nonebot-plugin-picstatus/issues/49)
+
 ### 2.1.1
 
 - 重新加入指令带图/回复图自定义背景功能

nonebot_plugin_picstatus/__init__.py

@@ -50,7 +50,7 @@ async def _():
 if config.ps_only_su:
     usage += "\n注意：仅SuperUser可以使用此指令"
 
-__version__ = "2.1.1"
+__version__ = "2.1.2"
 __plugin_meta__ = PluginMetadata(
     name="PicStatus",
     description="以图片形式显示当前设备的运行状态",

nonebot_plugin_picstatus/bg_provider.py

@@ -135,9 +135,21 @@ def __init__(self, preload_count: int):
         self.preload_count = preload_count
         self.backgrounds: List[BgData] = []
         self.tasks: List[aio.Task[None]] = []
-        self.task_signal = aio.Future[None]()
+        self.task_signal: Optional[aio.Future[None]] = None
         self.signal_wait_lock = aio.Lock()
 
+    def _get_signal(self) -> aio.Future[None]:
+        if (not self.task_signal) or self.task_signal.done():
+            self.task_signal = aio.Future()
+        return self.task_signal
+
+    def _wait_signal(self):
+        async def inner():
+            async with self.signal_wait_lock:
+                await self._get_signal()
+
+        return aio.wait_for(inner(), timeout=15)
+
     def create_preload_task(self):
         async def task_func():
             logger.debug("Started a preload background task")
@@ -148,13 +160,13 @@ async def task_func():
                 # if error occurred this should be an unexpected error
                 # need to let this error raise
                 logger.opt(exception=e).debug("Exception when preloading")
-                if not self.task_signal.done():
-                    self.task_signal.set_exception(e)
+                if not (s := self._get_signal()).done():
+                    s.set_exception(e)
             else:
                 logger.debug("A preload task done")
                 self.backgrounds.append(bg)
-                if not self.task_signal.done():
-                    self.task_signal.set_result(None)
+                if not (s := self._get_signal()).done():
+                    s.set_result(None)
             finally:
                 self.tasks.remove(task)
 
@@ -171,20 +183,11 @@ def start_preload(self, create_when_full: bool = False):
         for _ in range(task_count):
             self.create_preload_task()
 
-    async def wait_signal(self):
-        async def inner():
-            async with self.signal_wait_lock:
-                if self.task_signal.done():
-                    self.task_signal = aio.Future()
-                await self.task_signal
-
-        return await aio.wait_for(inner(), timeout=15)
-
     async def get(self) -> BgData:
         if not self.backgrounds:
             self.start_preload(create_when_full=True)
             if self.tasks:
-                await self.wait_signal()
+                await self._wait_signal()
             if not self.backgrounds:
                 raise RuntimeError("Failed to wait background")
         bg = self.backgrounds.pop(0)