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#
# Ouroboros - Copyright (C) 2016 - 2026
#
# Python API for Ouroboros
#
# Dimitri Staessens <dimitri@ouroboros.rocks>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public License
# version 2.1 as published by the Free Software Foundation.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., http://www.fsf.org/about/contact/.
#
"""Asynchronous flow event monitoring for Ouroboros."""
from __future__ import annotations
from enum import IntFlag
from typing import List, Optional, Tuple
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
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, exc_value, tb) -> 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."""
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):
"""Return the underlying ``fqueue_t *``.
Intended for use by :meth:`FlowSet.wait` within the same
package; not part of the user-facing API.
"""
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, exc_value, tb) -> 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."""
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."""
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."""
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).
"""
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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