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Name	Size	Permission
__init__.py	419 B	-rw-r--r--
__init__.pyc	508 B	-rw-r--r--
api.py	3.76 KB	-rw-r--r--
api.pyc	4.4 KB	-rw-r--r--
attr.py	12.16 KB	-rw-r--r--
attr.pyc	16.17 KB	-rw-r--r--
base.py	7.08 KB	-rw-r--r--
base.pyc	9.07 KB	-rw-r--r--
legacy.py	5.68 KB	-rw-r--r--
legacy.pyc	5.77 KB	-rw-r--r--
registry.py	7.5 KB	-rw-r--r--
registry.pyc	6.96 KB	-rw-r--r--

Code Editor : api.py

# event/api.py
# Copyright (C) 2005-2014 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php

"""Public API functions for the event system.

"""
from __future__ import absolute_import

from .. import util, exc
from .base import _registrars
from .registry import _EventKey

CANCEL = util.symbol('CANCEL')
NO_RETVAL = util.symbol('NO_RETVAL')

def _event_key(target, identifier, fn):
    for evt_cls in _registrars[identifier]:
        tgt = evt_cls._accept_with(target)
        if tgt is not None:
            return _EventKey(target, identifier, fn, tgt)
    else:
        raise exc.InvalidRequestError("No such event '%s' for target '%s'" %
                                      (identifier, target))

def listen(target, identifier, fn, *args, **kw):
    """Register a listener function for the given target.

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`.

"""

_event_key(target, identifier, fn).listen(*args, **kw)

def listens_for(target, identifier, *args, **kw):
    """Decorate a function as a listener for the given target + identifier.

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`.

"""
    def decorate(fn):
        listen(target, identifier, fn, *args, **kw)
        return fn
    return decorate

def remove(target, identifier, fn):
    """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

"""
    _event_key(target, identifier, fn).remove()

def contains(target, identifier, fn):
    """Return True if the given target/ident/fn is set up to listen.

.. versionadded:: 0.9.0

"""

return _event_key(target, identifier, fn).contains()

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Code Editor : api.py