1 # copyright 2014 LOGILAB S.A. (Paris, FRANCE), all rights reserved.

     2 # contact http://www.logilab.fr/ -- mailto:contact@logilab.fr

     3 #

     4 # This file is part of CubicWeb.

     5 #

     6 # CubicWeb is free software: you can redistribute it and/or modify it under the

     7 # terms of the GNU Lesser General Public License as published by the Free

     8 # Software Foundation, either version 2.1 of the License, or (at your option)

     9 # any later version.

    10 #

    11 # CubicWeb is distributed in the hope that it will be useful, but WITHOUT

    12 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

    13 # FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more

    14 # details.

    15 #

    16 # You should have received a copy of the GNU Lesser General Public License along

    17 # with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.

    18 

    19 """Helper functions for migrations that aren't reliable enough or too dangerous

    20 to be available in the standard migration environment

    21 """

    22 from __future__ import print_function

    23 

    24 __docformat__ = "restructuredtext en"

    25 

    26 def drop_entity_types_fast(*etypes, **kwargs):

    27     """drop an entity type bypassing all hooks

    28 

    29     here be dragons.

    30     """

    31     # XXX cascade deletion through composite relations?

    32 

    33     for etype in etypes:

    34 

    35         if etype not in schema:

    36             print('%s does not exist' % etype)

    37             continue

    38         etype = schema[etype]

    39 

    40         # ignore attributes and inlined rels since they'll be dropped anyway

    41         srels = [x.type for x in etype.subject_relations() if x.eid and not (x.final or x.inlined)]

    42 

    43         orels = [x.type for x in etype.object_relations() if x.eid and not x.inlined]

    44         inlined_rels = [x for x in etype.object_relations() if x.eid and x.inlined]

    45 

    46         # eids to be deleted could be listed in some other entity tables through inlined relations

    47         for rtype in inlined_rels:

    48             for subjtype in rtype.subjects(etype):

    49                 if subjtype in etypes:

    50                     continue

    51                 sql('UPDATE cw_%(stype)s SET cw_%(rtype)s = NULL '

    52                     'WHERE cw_%(rtype)s IN (SELECT eid FROM entities WHERE type = %%s)' %

    53                     {'stype': subjtype.type, 'rtype': rtype.type},

    54                     (etype.type,))

    55 

    56         for rel in srels:

    57             if all(subj in etypes for subj in rel.subjects()) or all(obj in etypes for obj in rel.objects()):

    58                 sql('DELETE FROM %s_relation' % rel.type)

    59             else:

    60                 sql('DELETE FROM %s_relation WHERE eid_from IN (SELECT eid FROM entities WHERE type = %%s)' % rel.type, (etype.type,))

    61         for rel in orels:

    62             if all(subj in etypes for subj in rel.subjects()) or all(obj in etypes for obj in rel.objects()):

    63                 sql('DELETE FROM %s_relation' % rel.type)

    64             else:

    65                 sql('DELETE FROM %s_relation WHERE eid_to IN (SELECT eid FROM entities WHERE type = %%s)' % rel, (etype.type,))

    66 

    67         sql('DELETE FROM appears WHERE uid IN (SELECT eid FROM entities WHERE type = %s)', (etype.type,))

    68         sql('DELETE FROM cw_%s' % etype.type)

    69         sql('DELETE FROM entities WHERE type = %s', (etype.type,))

    70 

    71     for etype in etypes:

    72         drop_entity_type(etype, **kwargs)