"""Cross-interpreter Queues High Level Module.""" import pickle import queue import time import weakref import _interpqueues as _queues from . import _crossinterp # aliases: from _interpqueues import ( QueueError, QueueNotFoundError, ) from ._crossinterp import ( UNBOUND_ERROR, UNBOUND_REMOVE, ) __all__ = [ 'UNBOUND', 'UNBOUND_ERROR', 'UNBOUND_REMOVE', 'create', 'list_all', 'Queue', 'QueueError', 'QueueNotFoundError', 'QueueEmpty', 'QueueFull', 'ItemInterpreterDestroyed', ] class QueueEmpty(QueueError, queue.Empty): """Raised from get_nowait() when the queue is empty. It is also raised from get() if it times out. """ class QueueFull(QueueError, queue.Full): """Raised from put_nowait() when the queue is full. It is also raised from put() if it times out. """ class ItemInterpreterDestroyed(QueueError, _crossinterp.ItemInterpreterDestroyed): """Raised from get() and get_nowait().""" _SHARED_ONLY = 0 _PICKLED = 1 UNBOUND = _crossinterp.UnboundItem.singleton('queue', __name__) def _serialize_unbound(unbound): if unbound is UNBOUND: unbound = _crossinterp.UNBOUND return _crossinterp.serialize_unbound(unbound) def _resolve_unbound(flag): resolved = _crossinterp.resolve_unbound(flag, ItemInterpreterDestroyed) if resolved is _crossinterp.UNBOUND: resolved = UNBOUND return resolved def create(maxsize=0, *, unbounditems=UNBOUND): """Return a new cross-interpreter queue. The queue may be used to pass data safely between interpreters. "unbounditems" sets the default for Queue.put(); see that method for supported values. The default value is UNBOUND, which replaces the unbound item. """ unbound = _serialize_unbound(unbounditems) unboundop, = unbound qid = _queues.create(maxsize, unboundop, -1) self = Queue(qid) self._set_unbound(unboundop, unbounditems) return self def list_all(): """Return a list of all open queues.""" queues = [] for qid, unboundop, _ in _queues.list_all(): self = Queue(qid) if not hasattr(self, '_unbound'): self._set_unbound(unboundop) else: assert self._unbound[0] == unboundop queues.append(self) return queues _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) # for pickling: def __reduce__(self): return (type(self), (self._id,)) def _set_unbound(self, op, items=None): assert not hasattr(self, '_unbound') if items is None: items = _resolve_unbound(op) unbound = (op, items) self._unbound = unbound return unbound @property def id(self): return self._id @property def unbounditems(self): try: _, items = self._unbound except AttributeError: op, _ = _queues.get_queue_defaults(self._id) _, items = self._set_unbound(op) return items @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, *, unbounditems=None, _delay=10 / 1000, # 10 milliseconds ): """Add the object to the queue. This blocks while the queue is full. For most objects, the object received through Queue.get() will be a new one, equivalent to the original and not sharing any actual underlying data. The notable exceptions include cross-interpreter types (like Queue) and memoryview, where the underlying data is actually shared. Furthermore, some types can be sent through a queue more efficiently than others. This group includes various immutable types like int, str, bytes, and tuple (if the items are likewise efficiently shareable). See interpreters.is_shareable(). "unbounditems" controls the behavior of Queue.get() for the given object if the current interpreter (calling put()) is later destroyed. If "unbounditems" is None (the default) then it uses the queue's default, set with create_queue(), which is usually UNBOUND. If "unbounditems" is UNBOUND_ERROR then get() will raise an ItemInterpreterDestroyed exception if the original interpreter has been destroyed. This does not otherwise affect the queue; the next call to put() will work like normal, returning the next item in the queue. If "unbounditems" is UNBOUND_REMOVE then the item will be removed from the queue as soon as the original interpreter is destroyed. Be aware that this will introduce an imbalance between put() and get() calls. If "unbounditems" is UNBOUND then it is returned by get() in place of the unbound item. """ if unbounditems is None: unboundop = -1 else: unboundop, = _serialize_unbound(unbounditems) 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, unboundop) except QueueFull as exc: if timeout is not None and time.time() >= end: raise # re-raise time.sleep(_delay) else: break def put_nowait(self, obj, *, unbounditems=None): if unbounditems is None: unboundop = -1 else: unboundop, = _serialize_unbound(unbounditems) _queues.put(self._id, obj, unboundop) 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 the next item's original interpreter has been destroyed then the "next object" is determined by the value of the "unbounditems" argument to put(). """ 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: obj, unboundop = _queues.get(self._id) except QueueEmpty as exc: if timeout is not None and time.time() >= end: raise # re-raise time.sleep(_delay) else: break if unboundop is not None: assert obj is None, repr(obj) return _resolve_unbound(unboundop) 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: obj, unboundop = _queues.get(self._id) except QueueEmpty as exc: raise # re-raise if unboundop is not None: assert obj is None, repr(obj) return _resolve_unbound(unboundop) return obj _queues._register_heap_types(Queue, QueueEmpty, QueueFull)