o ïÅ[h«ã@s€dZddlmZddlmZddlmZddlmZddlm Z e   d ¡Z e   d ¡Z d d „Z d d„Zdd„Zdd„Zdd„ZdS)z,Public API functions for the event system. é)Úabsolute_importé)Ú _registrars)Ú _EventKeyé)Úexc)ÚutilÚCANCELÚ NO_RETVALcCsDt|D]}| |¡}|durt||||ƒSqt d||f¡‚)Nz"No such event '%s' for target '%s')rZ _accept_withrrZInvalidRequestError)ÚtargetÚ identifierÚfnZevt_clsZtgt©rú{/home/ubuntu/experiments/live_experiments/Pythonexperiments/Otree/venv/lib/python3.10/site-packages/sqlalchemy/event/api.pyÚ _event_keys  ÿ ÿrcOst|||ƒj|i|¤ŽdS)ak Register a listener function for the given target. The :func:`.listen` function is part of the primary interface for the SQLAlchemy event system, documented at :ref:`event_toplevel`. e.g.:: from sqlalchemy import event from sqlalchemy.schema import UniqueConstraint def unique_constraint_name(const, table): const.name = "uq_%s_%s" % ( table.name, list(const.columns)[0].name ) event.listen( UniqueConstraint, "after_parent_attach", unique_constraint_name) A given function can also be invoked for only the first invocation of the event using the ``once`` argument:: def on_config(): do_config() event.listen(Mapper, "before_configure", on_config, once=True) .. versionadded:: 0.9.4 Added ``once=True`` to :func:`.event.listen` and :func:`.event.listens_for`. .. warning:: The ``once`` argument does not imply automatic de-registration of the listener function after it has been invoked a first time; a listener entry will remain associated with the target object. Associating an arbitrarily high number of listeners without explicitly removing them will cause memory to grow unbounded even if ``once=True`` is specified. .. note:: The :func:`.listen` function cannot be called at the same time that the target event is being run. This has implications for thread safety, and also means an event cannot be added from inside the listener function for itself. The list of events to be run are present inside of a mutable collection that can't be changed during iteration. Event registration and removal is not intended to be a "high velocity" operation; it is a configurational operation. For systems that need to quickly associate and deassociate with events at high scale, use a mutable structure that is handled from inside of a single listener. .. versionchanged:: 1.0.0 - a ``collections.deque()`` object is now used as the container for the list of events, which explicitly disallows collection mutation while the collection is being iterated. .. seealso:: :func:`.listens_for` :func:`.remove` N)rÚlisten)r r r ÚargsÚkwrrrr"sDrcs‡‡‡‡fdd„}|S)a~Decorate a function as a listener for the given target + identifier. The :func:`.listens_for` decorator is part of the primary interface for the SQLAlchemy event system, documented at :ref:`event_toplevel`. e.g.:: from sqlalchemy import event from sqlalchemy.schema import UniqueConstraint @event.listens_for(UniqueConstraint, "after_parent_attach") def unique_constraint_name(const, table): const.name = "uq_%s_%s" % ( table.name, list(const.columns)[0].name ) A given function can also be invoked for only the first invocation of the event using the ``once`` argument:: @event.listens_for(Mapper, "before_configure", once=True) def on_config(): do_config() .. versionadded:: 0.9.4 Added ``once=True`` to :func:`.event.listen` and :func:`.event.listens_for`. .. warning:: The ``once`` argument does not imply automatic de-registration of the listener function after it has been invoked a first time; a listener entry will remain associated with the target object. Associating an arbitrarily high number of listeners without explicitly removing them will cause memory to grow unbounded even if ``once=True`` is specified. .. seealso:: :func:`.listen` - general description of event listening cstˆˆ|gˆ¢Riˆ¤Ž|S)N)r)r ©rr rr rrÚdecorate“szlistens_for..decorater)r r rrrrrrÚ listens_foris*rcCst|||ƒ ¡dS)a Remove an event listener. The arguments here should match exactly those which were sent to :func:`.listen`; all the event registration which proceeded as a result of this call will be reverted by calling :func:`.remove` with the same arguments. e.g.:: # if a function was registered like this... @event.listens_for(SomeMappedClass, "before_insert", propagate=True) def my_listener_function(*arg): pass # ... it's removed like this event.remove(SomeMappedClass, "before_insert", my_listener_function) Above, the listener function associated with ``SomeMappedClass`` was also propagated to subclasses of ``SomeMappedClass``; the :func:`.remove` function will revert all of these operations. .. versionadded:: 0.9.0 .. note:: The :func:`.remove` function cannot be called at the same time that the target event is being run. This has implications for thread safety, and also means an event cannot be removed from inside the listener function for itself. The list of events to be run are present inside of a mutable collection that can't be changed during iteration. Event registration and removal is not intended to be a "high velocity" operation; it is a configurational operation. For systems that need to quickly associate and deassociate with events at high scale, use a mutable structure that is handled from inside of a single listener. .. versionchanged:: 1.0.0 - a ``collections.deque()`` object is now used as the container for the list of events, which explicitly disallows collection mutation while the collection is being iterated. .. seealso:: :func:`.listen` N)rÚremove©r r r rrrršs1rcCst|||ƒ ¡S)z`Return True if the given target/ident/fn is set up to listen. .. versionadded:: 0.9.0 )rÚcontainsrrrrrÎsrN)Ú__doc__Ú __future__rÚbaserÚregistryrÚrrÚsymbolr r rrrrrrrrrÚs        G1 4