6 files changed, 214 insertions, 0 deletions
diff --git a/venv/lib/python3.11/site-packages/litestar/events/__init__.py b/venv/lib/python3.11/site-packages/litestar/events/__init__.py
new file mode 100644
index 0000000..a291141
--- /dev/null
+++ b/venv/lib/python3.11/site-packages/litestar/events/__init__.py
@@ -0,0 +1,4 @@
+from .emitter import BaseEventEmitterBackend, SimpleEventEmitter
+from .listener import EventListener, listener
+
+__all__ = ("EventListener", "SimpleEventEmitter", "BaseEventEmitterBackend", "listener")
diff --git a/venv/lib/python3.11/site-packages/litestar/events/__pycache__/__init__.cpython-311.pyc b/venv/lib/python3.11/site-packages/litestar/events/__pycache__/__init__.cpython-311.pyc
new file mode 100644
index 0000000..bc8ee50
--- /dev/null
+++ b/venv/lib/python3.11/site-packages/litestar/events/__pycache__/__init__.cpython-311.pyc
diff --git a/venv/lib/python3.11/site-packages/litestar/events/__pycache__/emitter.cpython-311.pyc b/venv/lib/python3.11/site-packages/litestar/events/__pycache__/emitter.cpython-311.pyc
new file mode 100644
index 0000000..f59ec24
--- /dev/null
+++ b/venv/lib/python3.11/site-packages/litestar/events/__pycache__/emitter.cpython-311.pyc
diff --git a/venv/lib/python3.11/site-packages/litestar/events/__pycache__/listener.cpython-311.pyc b/venv/lib/python3.11/site-packages/litestar/events/__pycache__/listener.cpython-311.pyc
new file mode 100644
index 0000000..666bcbc
--- /dev/null
+++ b/venv/lib/python3.11/site-packages/litestar/events/__pycache__/listener.cpython-311.pyc
diff --git a/venv/lib/python3.11/site-packages/litestar/events/emitter.py b/venv/lib/python3.11/site-packages/litestar/events/emitter.py
new file mode 100644
index 0000000..7c33c9e
--- /dev/null
+++ b/venv/lib/python3.11/site-packages/litestar/events/emitter.py
@@ -0,0 +1,134 @@
+from __future__ import annotations
+
+import math
+import sys
+from abc import ABC, abstractmethod
+from collections import defaultdict
+from contextlib import AsyncExitStack
+from functools import partial
+from typing import TYPE_CHECKING, Any, Sequence
+
+if sys.version_info < (3, 9):
+    from typing import AsyncContextManager
+else:
+    from contextlib import AbstractAsyncContextManager as AsyncContextManager
+
+import anyio
+
+from litestar.exceptions import ImproperlyConfiguredException
+
+if TYPE_CHECKING:
+    from types import TracebackType
+
+    from anyio.streams.memory import MemoryObjectReceiveStream, MemoryObjectSendStream
+
+    from litestar.events.listener import EventListener
+
+__all__ = ("BaseEventEmitterBackend", "SimpleEventEmitter")
+
+
+class BaseEventEmitterBackend(AsyncContextManager["BaseEventEmitterBackend"], ABC):
+    """Abstract class used to define event emitter backends."""
+
+    __slots__ = ("listeners",)
+
+    listeners: defaultdict[str, set[EventListener]]
+
+    def __init__(self, listeners: Sequence[EventListener]) -> None:
+        """Create an event emitter instance.
+
+        Args:
+            listeners: A list of listeners.
+        """
+        self.listeners = defaultdict(set)
+        for listener in listeners:
+            for event_id in listener.event_ids:
+                self.listeners[event_id].add(listener)
+
+    @abstractmethod
+    def emit(self, event_id: str, *args: Any, **kwargs: Any) -> None:
+        """Emit an event to all attached listeners.
+
+        Args:
+            event_id: The ID of the event to emit, e.g 'my_event'.
+            *args: args to pass to the listener(s).
+            **kwargs: kwargs to pass to the listener(s)
+
+        Returns:
+            None
+        """
+        raise NotImplementedError("not implemented")
+
+
+class SimpleEventEmitter(BaseEventEmitterBackend):
+    """Event emitter the works only in the current process"""
+
+    __slots__ = ("_queue", "_exit_stack", "_receive_stream", "_send_stream")
+
+    def __init__(self, listeners: Sequence[EventListener]) -> None:
+        """Create an event emitter instance.
+
+        Args:
+            listeners: A list of listeners.
+        """
+        super().__init__(listeners=listeners)
+        self._receive_stream: MemoryObjectReceiveStream | None = None
+        self._send_stream: MemoryObjectSendStream | None = None
+        self._exit_stack: AsyncExitStack | None = None
+
+    async def _worker(self, receive_stream: MemoryObjectReceiveStream) -> None:
+        """Run items from ``receive_stream`` in a task group.
+
+        Returns:
+            None
+        """
+        async with receive_stream, anyio.create_task_group() as task_group:
+            async for item in receive_stream:
+                fn, args, kwargs = item
+                if kwargs:
+                    fn = partial(fn, **kwargs)
+                task_group.start_soon(fn, *args)  # pyright: ignore[reportGeneralTypeIssues]
+
+    async def __aenter__(self) -> SimpleEventEmitter:
+        self._exit_stack = AsyncExitStack()
+        send_stream, receive_stream = anyio.create_memory_object_stream(math.inf)  # type: ignore[var-annotated]
+        self._send_stream = send_stream
+        task_group = anyio.create_task_group()
+
+        await self._exit_stack.enter_async_context(task_group)
+        await self._exit_stack.enter_async_context(send_stream)
+        task_group.start_soon(self._worker, receive_stream)
+
+        return self
+
+    async def __aexit__(
+        self,
+        exc_type: type[BaseException] | None,
+        exc_val: BaseException | None,
+        exc_tb: TracebackType | None,
+    ) -> None:
+        if self._exit_stack:
+            await self._exit_stack.__aexit__(exc_type, exc_val, exc_tb)
+
+        self._exit_stack = None
+        self._send_stream = None
+
+    def emit(self, event_id: str, *args: Any, **kwargs: Any) -> None:
+        """Emit an event to all attached listeners.
+
+        Args:
+            event_id: The ID of the event to emit, e.g 'my_event'.
+            *args: args to pass to the listener(s).
+            **kwargs: kwargs to pass to the listener(s)
+
+        Returns:
+            None
+        """
+        if not (self._send_stream and self._exit_stack):
+            raise RuntimeError("Emitter not initialized")
+
+        if listeners := self.listeners.get(event_id):
+            for listener in listeners:
+                self._send_stream.send_nowait((listener.fn, args, kwargs))
+            return
+        raise ImproperlyConfiguredException(f"no event listeners are registered for event ID: {event_id}")
diff --git a/venv/lib/python3.11/site-packages/litestar/events/listener.py b/venv/lib/python3.11/site-packages/litestar/events/listener.py
new file mode 100644
index 0000000..63c9848
--- /dev/null
+++ b/venv/lib/python3.11/site-packages/litestar/events/listener.py
@@ -0,0 +1,76 @@
+from __future__ import annotations
+
+import logging
+from typing import TYPE_CHECKING, Any
+
+from litestar.exceptions import ImproperlyConfiguredException
+from litestar.utils import ensure_async_callable
+
+if TYPE_CHECKING:
+    from litestar.types import AnyCallable, AsyncAnyCallable
+
+__all__ = ("EventListener", "listener")
+
+logger = logging.getLogger(__name__)
+
+
+class EventListener:
+    """Decorator for event listeners"""
+
+    __slots__ = ("event_ids", "fn", "listener_id")
+
+    fn: AsyncAnyCallable
+
+    def __init__(self, *event_ids: str) -> None:
+        """Create a decorator for event handlers.
+
+        Args:
+            *event_ids: The id of the event to listen to or a list of
+                event ids to listen to.
+        """
+        self.event_ids: frozenset[str] = frozenset(event_ids)
+
+    def __call__(self, fn: AnyCallable) -> EventListener:
+        """Decorate a callable by wrapping it inside an instance of EventListener.
+
+        Args:
+            fn: Callable to decorate.
+
+        Returns:
+            An instance of EventListener
+        """
+        if not callable(fn):
+            raise ImproperlyConfiguredException("EventListener instance should be called as a decorator on a callable")
+
+        self.fn = self.wrap_in_error_handler(ensure_async_callable(fn))
+
+        return self
+
+    @staticmethod
+    def wrap_in_error_handler(fn: AsyncAnyCallable) -> AsyncAnyCallable:
+        """Wrap a listener function to handle errors.
+
+        Listeners are executed concurrently in a TaskGroup, so we need to ensure that exceptions do not propagate
+        to the task group which results in any other unfinished listeners to be cancelled, and the receive stream to
+        be closed.
+
+        See https://github.com/litestar-org/litestar/issues/2809
+
+        Args:
+            fn: The listener function to wrap.
+        """
+
+        async def wrapped(*args: Any, **kwargs: Any) -> None:
+            """Wrap a listener function to handle errors."""
+            try:
+                await fn(*args, **kwargs)
+            except Exception as exc:
+                logger.exception("Error while executing listener %s: %s", fn.__name__, exc)
+
+        return wrapped
+
+    def __hash__(self) -> int:
+        return hash(self.event_ids) + hash(self.fn)
+
+
+listener = EventListener