# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php

"""Descriptor properties are more "auxiliary" properties
that exist as configurational elements, but don't participate
as actively in the load/persist ORM loop.

"""

from sqlalchemy.orm.interfaces import \
    MapperProperty, PropComparator, StrategizedProperty
from sqlalchemy.orm.mapper import _none_set
from sqlalchemy.orm import attributes
from sqlalchemy import util, sql, exc as sa_exc, event, schema
from sqlalchemy.sql import expression
properties = util.importlater('sqlalchemy.orm', 'properties')

class DescriptorProperty(MapperProperty):
    """:class:`.MapperProperty` which proxies access to a 
        user-defined descriptor."""

    doc = None

    def instrument_class(self, mapper):
        prop = self

        class _ProxyImpl(object):
            accepts_scalar_loader = False
            expire_missing = True

            def __init__(self, key):

# orm/util.py
# Copyright (C) 2005-2011 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

import sqlalchemy.exceptions as sa_exc
from sqlalchemy import sql, util
from sqlalchemy.sql import expression, util as sql_util, operators
from sqlalchemy.orm.interfaces import MapperExtension, EXT_CONTINUE,\
                                PropComparator, MapperProperty,\
                                AttributeExtension
from sqlalchemy.orm import attributes, exc

mapperlib = util.importlater("sqlalchemy.orm", "mapperlib")

all_cascades = frozenset(("delete", "delete-orphan", "all", "merge",
                          "expunge", "save-update", "refresh-expire",
                          "none"))

_INSTRUMENTOR = ('mapper', 'instrumentor')

class CascadeOptions(object):
    """Keeps track of the options sent to relationship().cascade"""

    def __init__(self, arg=""):
        if not arg:
            values = set()
        else:
            values = set(c.strip() for c in arg.split(','))
        self.delete_orphan = "delete-orphan" in values

Contains various base classes used throughout the ORM.

Defines the now deprecated ORM extension classes as well
as ORM internals.

Other than the deprecated extensions, this module and the
classes within should be considered mostly private.

"""

from itertools import chain

from sqlalchemy import exc as sa_exc
from sqlalchemy import util
from sqlalchemy.sql import operators
deque = util.importlater('collections').deque

mapperutil = util.importlater('sqlalchemy.orm', 'util')

collections = None

__all__ = (
    'AttributeExtension',
    'EXT_CONTINUE',
    'EXT_STOP',
    'ExtensionOption',
    'InstrumentationManager',
    'LoaderStrategy',
    'MapperExtension',
    'MapperOption',
    'MapperProperty',

# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php

"""The internals for the unit of work system.

The session's flush() process passes objects to a contextual object
here, which assembles flush tasks based on mappers and their properties,
organizes them in order of dependency, and executes.

"""

from sqlalchemy import util, topological
from sqlalchemy.orm import attributes, interfaces
from sqlalchemy.orm import util as mapperutil
from sqlalchemy.orm.util import _state_mapper
session = util.importlater("sqlalchemy.orm", "session")

class UOWEventHandler(interfaces.AttributeExtension):
    """An event handler added to all relationship attributes which handles
    session cascade operations.
    """

    active_history = False

    def __init__(self, key):
        self.key = key

    def append(self, state, item, initiator):
        # process "save_update" cascade rules for when 
        # an instance is appended to the list of another instance

"""Contains Schema element and compilers for foreign table and fdw.
"""

from sqlalchemy.ext.compiler import compiles
from sqlalchemy import util as sqlautil
from sqlalchemy.schema import DDLElement, Table, _bind_or_error
from sqlalchemy import sql
from sqlalchemy import types
from .util import sql_options

ddl = sqlautil.importlater('sqlalchemy.engine', 'ddl')


class ForeignTable(Table):
    """Defines a Foreign Table

    A Foreign Table is a postgresql table located on a remote server.
    To create remote servers, look at :class:`ForeignDataWrapper`.

    This functionality has been tagged stable in postgresql 9.1

    Assuming you already created a server 'myserver', a foreign table can be
    defined on it like this::

        mytable = ForeignTable("mytable", metadata,
                               Column('id', Integer),
                               Column('name', Unicode),
                               fdw_server='myserver)

    You can then use it like any table, except:
        - only select statements are supported

with instances.

This module is usually not directly visible to user applications, but
defines a large part of the ORM's interactivity.


"""

import operator
from operator import itemgetter

from sqlalchemy import util, event, exc as sa_exc
from sqlalchemy.orm import interfaces, collections, events


mapperutil = util.importlater("sqlalchemy.orm", "util")

PASSIVE_NO_RESULT = util.symbol('PASSIVE_NO_RESULT')
ATTR_WAS_SET = util.symbol('ATTR_WAS_SET')
ATTR_EMPTY = util.symbol('ATTR_EMPTY')
NO_VALUE = util.symbol('NO_VALUE')
NEVER_SET = util.symbol('NEVER_SET')

PASSIVE_RETURN_NEVER_SET = util.symbol('PASSIVE_RETURN_NEVER_SET'
"""Symbol indicating that loader callables can be 
fired off, but if no callable is applicable and no value is
present, the attribute should remain non-initialized.
NEVER_SET is returned in this case.
""")

PASSIVE_NO_INITIALIZE = util.symbol('PASSIVE_NO_INITIALIZE',

# sqlalchemy/events.py
# Copyright (C) 2005-2013 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

"""Core event interfaces."""

from sqlalchemy import event, exc, util
engine = util.importlater('sqlalchemy', 'engine')
pool = util.importlater('sqlalchemy', 'pool')


class DDLEvents(event.Events):
    """
    Define event listeners for schema objects,
    that is, :class:`.SchemaItem` and :class:`.SchemaEvent`
    subclasses, including :class:`.MetaData`, :class:`.Table`,
    :class:`.Column`.

    :class:`.MetaData` and :class:`.Table` support events
    specifically regarding when CREATE and DROP
    DDL is emitted to the database.

    Attachment events are also provided to customize
    behavior whenever a child schema element is associated
    with a parent, such as, when a :class:`.Column` is associated
    with its :class:`.Table`, when a :class:`.ForeignKeyConstraint`
    is associated with a :class:`.Table`, etc.

    Example using the ``after_create`` event::

Defines the now deprecated ORM extension classes as well
as ORM internals.

Other than the deprecated extensions, this module and the
classes within should be considered mostly private.

"""

from itertools import chain

from sqlalchemy import exc as sa_exc
from sqlalchemy import util
from sqlalchemy.sql import operators
deque = __import__('collections').deque

mapperutil = util.importlater('sqlalchemy.orm', 'util')

collections = None

__all__ = (
    'AttributeExtension',
    'EXT_CONTINUE',
    'EXT_STOP',
    'ExtensionOption',
    'InstrumentationManager',
    'LoaderStrategy',
    'MapperExtension',
    'MapperOption',
    'MapperProperty',
    'PropComparator',
    'PropertyOption',

# sqlalchemy/events.py
# Copyright (C) 2005-2012 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

"""Core event interfaces."""

from sqlalchemy import event, exc, util

engine = util.importlater("sqlalchemy", "engine")
pool = util.importlater("sqlalchemy", "pool")


class DDLEvents(event.Events):
    """
    Define event listeners for schema objects,
    that is, :class:`.SchemaItem` and :class:`.SchemaEvent`
    subclasses, including :class:`.MetaData`, :class:`.Table`,
    :class:`.Column`.

    :class:`.MetaData` and :class:`.Table` support events
    specifically regarding when CREATE and DROP
    DDL is emitted to the database.

    Attachment events are also provided to customize
    behavior whenever a child schema element is associated
    with a parent, such as, when a :class:`.Column` is associated
    with its :class:`.Table`, when a :class:`.ForeignKeyConstraint`
    is associated with a :class:`.Table`, etc.

# orm/events.py
# Copyright (C) 2005-2011 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

"""ORM event interfaces.

"""
from sqlalchemy import event, exc, util
orm = util.importlater("sqlalchemy", "orm")
import inspect

class InstrumentationEvents(event.Events):
    """Events related to class instrumentation events.

    The listeners here support being established against
    any new style class, that is any object that is a subclass
    of 'type'.  Events will then be fired off for events
    against that class as well as all subclasses.
    'type' itself is also accepted as a target
    in which case the events fire for all classes.

    """

    @classmethod
    def _accept_with(cls, target):
        if isinstance(target, type):
            return orm.instrumentation.instrumentation_registry
        else:
            return None