cpython/Lib/test/support/interpreters/queues.py

173 lines
4.3 KiB
Python

"""Cross-interpreter Queues High Level Module."""
import queue
import time
import weakref
import _xxinterpqueues as _queues
# aliases:
from _xxinterpqueues import (
QueueError, QueueNotFoundError,
)
__all__ = [
'create', 'list_all',
'Queue',
'QueueError', 'QueueNotFoundError', 'QueueEmpty', 'QueueFull',
]
class QueueEmpty(_queues.QueueEmpty, queue.Empty):
"""Raised from get_nowait() when the queue is empty.
It is also raised from get() if it times out.
"""
class QueueFull(_queues.QueueFull, queue.Full):
"""Raised from put_nowait() when the queue is full.
It is also raised from put() if it times out.
"""
def create(maxsize=0):
"""Return a new cross-interpreter queue.
The queue may be used to pass data safely between interpreters.
"""
qid = _queues.create(maxsize)
return Queue(qid)
def list_all():
"""Return a list of all open queues."""
return [Queue(qid)
for qid in _queues.list_all()]
_known_queues = weakref.WeakValueDictionary()
class Queue:
"""A cross-interpreter queue."""
def __new__(cls, id, /):
# There is only one instance for any given ID.
if isinstance(id, int):
id = int(id)
else:
raise TypeError(f'id must be an int, got {id!r}')
try:
self = _known_queues[id]
except KeyError:
self = super().__new__(cls)
self._id = id
_known_queues[id] = self
_queues.bind(id)
return self
def __del__(self):
try:
_queues.release(self._id)
except QueueNotFoundError:
pass
try:
del _known_queues[self._id]
except KeyError:
pass
def __repr__(self):
return f'{type(self).__name__}({self.id})'
def __hash__(self):
return hash(self._id)
@property
def id(self):
return self._id
@property
def maxsize(self):
try:
return self._maxsize
except AttributeError:
self._maxsize = _queues.get_maxsize(self._id)
return self._maxsize
def empty(self):
return self.qsize() == 0
def full(self):
return _queues.is_full(self._id)
def qsize(self):
return _queues.get_count(self._id)
def put(self, obj, timeout=None, *,
_delay=10 / 1000, # 10 milliseconds
):
"""Add the object to the queue.
This blocks while the queue is full.
"""
if timeout is not None:
timeout = int(timeout)
if timeout < 0:
raise ValueError(f'timeout value must be non-negative')
end = time.time() + timeout
while True:
try:
_queues.put(self._id, obj)
except _queues.QueueFull as exc:
if timeout is not None and time.time() >= end:
exc.__class__ = QueueFull
raise # re-raise
time.sleep(_delay)
else:
break
def put_nowait(self, obj):
try:
return _queues.put(self._id, obj)
except _queues.QueueFull as exc:
exc.__class__ = QueueFull
raise # re-raise
def get(self, timeout=None, *,
_delay=10 / 1000, # 10 milliseconds
):
"""Return the next object from the queue.
This blocks while the queue is empty.
"""
if timeout is not None:
timeout = int(timeout)
if timeout < 0:
raise ValueError(f'timeout value must be non-negative')
end = time.time() + timeout
while True:
try:
return _queues.get(self._id)
except _queues.QueueEmpty as exc:
if timeout is not None and time.time() >= end:
exc.__class__ = QueueEmpty
raise # re-raise
time.sleep(_delay)
return obj
def get_nowait(self):
"""Return the next object from the channel.
If the queue is empty then raise QueueEmpty. Otherwise this
is the same as get().
"""
try:
return _queues.get(self._id)
except _queues.QueueEmpty as exc:
exc.__class__ = QueueEmpty
raise # re-raise
_queues._register_queue_type(Queue)