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#
# SPDX-FileCopyrightText: 2016 - 2026 Dimitri Staessens
# SPDX-License-Identifier: LGPL-2.1-only
#
"""
Asynchronous flow event monitoring for Ouroboros.
"""
from __future__ import annotations
from enum import IntFlag
from typing import TYPE_CHECKING, Any, List, Optional, Tuple, Type
from _ouroboros_dev_cffi import ffi, lib
from ouroboros._timespec import fl_to_timespec
from ouroboros.dev import Flow
from ouroboros.errors import FlowEventError, raise_errno
if TYPE_CHECKING:
from types import TracebackType
class FEventType(IntFlag):
"""
Types of flow events.
"""
FLOW_PKT = lib.FLOW_PKT
FLOW_DOWN = lib.FLOW_DOWN
FLOW_UP = lib.FLOW_UP
FLOW_ALLOC = lib.FLOW_ALLOC
FLOW_DEALLOC = lib.FLOW_DEALLOC
FLOW_PEER = lib.FLOW_PEER
class FEventQueue:
"""
A queue of flow events waiting to be drained.
"""
def __init__(self) -> None:
self._fq = lib.fqueue_create()
if self._fq == ffi.NULL:
raise MemoryError("Failed to create FEventQueue")
def __enter__(self) -> FEventQueue:
return self
def __exit__(self, exc_type: Optional[Type[BaseException]],
exc_value: Optional[BaseException],
tb: Optional[TracebackType]) -> None:
self.destroy()
def __del__(self) -> None:
self.destroy()
def destroy(self) -> None:
"""
Destroy the underlying queue. Idempotent.
"""
if self._fq != ffi.NULL:
lib.fqueue_destroy(self._fq)
self._fq = ffi.NULL
def next(self) -> Tuple[Flow, FEventType]:
"""
Return the next ``(flow, event_type)`` pair from the queue.
:return: The :class:`~ouroboros.dev.Flow` the event occurred
on, and its :class:`FEventType`.
:raises FlowEventError: On a negative ouroboros return code.
"""
fd = lib.fqueue_next(self._fq)
raise_errno(fd, default=FlowEventError)
_type = lib.fqueue_type(self._fq)
raise_errno(_type, default=FlowEventError)
return Flow(fd), FEventType(_type)
@property
def handle(self) -> Any:
"""
Return the underlying ``fqueue_t *``.
:return: The underlying ``fqueue_t *`` CFFI pointer.
"""
return self._fq
class FlowSet:
"""
A set of flows that can be monitored for events.
"""
def __init__(self, flows: Optional[List[Flow]] = None) -> None:
self._set = lib.fset_create()
if self._set == ffi.NULL:
raise MemoryError("Failed to create FlowSet")
if flows is not None:
for flow in flows:
if lib.fset_add(self._set, flow.fileno()) != 0:
lib.fset_destroy(self._set)
self._set = ffi.NULL
raise MemoryError(f"Failed to add flow {flow.fileno()}.")
def __enter__(self) -> FlowSet:
return self
def __exit__(self, exc_type: Optional[Type[BaseException]],
exc_value: Optional[BaseException],
tb: Optional[TracebackType]) -> None:
self.destroy()
def __del__(self) -> None:
self.destroy()
def destroy(self) -> None:
"""
Destroy the underlying set. Idempotent.
"""
if self._set != ffi.NULL:
lib.fset_destroy(self._set)
self._set = ffi.NULL
def add(self, flow: Flow) -> None:
"""
Add *flow* to this set.
:param flow: The flow to add to this set.
:raises ValueError: If the FlowSet has been destroyed.
:raises MemoryError: If the flow could not be added.
"""
if self._set == ffi.NULL:
raise ValueError("FlowSet has been destroyed")
if lib.fset_add(self._set, flow.fileno()) != 0:
raise MemoryError(f"Failed to add flow {flow.fileno()}")
def zero(self) -> None:
"""
Remove all flows from this set.
:raises ValueError: If the FlowSet has been destroyed.
"""
if self._set == ffi.NULL:
raise ValueError("FlowSet has been destroyed")
lib.fset_zero(self._set)
def remove(self, flow: Flow) -> None:
"""
Remove *flow* from this set.
:param flow: The flow to remove from this set.
:raises ValueError: If the FlowSet has been destroyed.
"""
if self._set == ffi.NULL:
raise ValueError("FlowSet has been destroyed")
lib.fset_del(self._set, flow.fileno())
def wait(self,
fq: FEventQueue,
timeo: Optional[float] = None) -> None:
"""
Wait for at least one event on one of the monitored flows.
:param fq: The :class:`FEventQueue` to drain events into.
:param timeo: Wait timeout in seconds (None blocks forever).
:raises ValueError: If the FlowSet has been destroyed.
:raises FlowEventError: On a negative ouroboros return code.
"""
if self._set == ffi.NULL:
raise ValueError("FlowSet has been destroyed")
_timeo = fl_to_timespec(ffi, timeo)
rc = lib.fevent(self._set, fq.handle, _timeo)
raise_errno(rc, default=FlowEventError)
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