[win32] fix deadlock occuring on the sequence tables with SQLServer
actually, this deadlock would occur with any db backend other that PostgreSQL
as the previous code was heavily relying on PG's SEQUENCE facility, not available
elsewhere.
Deadlock description:
Thread1 starts creating entities (and therefore calls create_eid):
-> this creates a DB-level lock on the entities_id_seq table, which
will last until end of transaction
Thread2 calls create_eid, which acquires the Python lock object, but
updating the entities_id_seq is held by the DB lock
Thread1 wants to create a new entity, calls create_eid, and is stuck by
the Python lock object held by Thread2.
Solution:
use a separate connection to read and write the entities_id_seq table.
# copyright 2003-2010 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of CubicWeb.
#
# CubicWeb is free software: you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option)
# any later version.
#
# CubicWeb is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with CubicWeb. If not, see <http://www.gnu.org/licenses/>.
"""cubicweb extensions for twill
"""
import re
from urllib import quote
from twill import commands as twc
# convenience / consistency renaming
has_text = twc.find
hasnt_text = twc.notfind
# specific commands
_LINK = re.compile('<a.*?href="(.*?)".*?>(.*?)</a>', re.I | re.S)
def has_link(text, url=''):
browser = twc.get_browser()
html = browser.get_html()
if html:
for match in _LINK.finditer(html):
linkurl = match.group(1)
linktext = match.group(2)
if linktext == text:
# if url is specified linkurl must match
if url and linkurl != url:
continue
return
raise AssertionError('link %s (%s) not found' % (text, url))
def view(rql, vid=''):
"""
>> view 'Project P'
apply <vid> to <rql>'s rset
"""
if vid:
twc.go('view?rql=%s&vid=%s' % (quote(rql), vid))
else:
twc.go('view?rql=%s' % quote(rql))
def create(etype):
"""
>> create Project
go to <etype>'s creation page
"""
twc.go('view?etype=%s&vid=creation' % etype)
def edit(rql):
"""
>> edit "Project P WHERE P eid 123"
calls edition view for <rql>
"""
twc.go('view?rql=%s&vid=edition' % quote(rql))
def setvalue(formname, fieldname, value):
"""
>> setvalue entityForm name pylint
sets the field's value in the form
<forname> should either be the form's index, the form's name
or the form's id
"""
browser = twc.get_browser()
form = browser.get_form(formname)
if form is None:
# try to find if one of the forms has <formname> as id
for index, form in enumerate(browser._browser.forms()):
# forms in cubicweb don't always have a name
if form.attrs.get('id') == formname:
# browser.get_form_field knows how to deal with form index
formname = str(index+1)
break
else:
raise ValueError('could not find form named <%s>' % formname)
eid = browser.get_form_field(form, 'eid').value
twc.formvalue(formname, '%s:%s' % (fieldname, eid), value)
def submitform(formname, submit_button=None):
"""
>> submitform entityForm
Submit the form named entityForm. This is useful when the form is pre-filed
and we only want to click on submit.
(The original submit command chooses the form to submit according to the last
formvalue instruction)
"""
browser = twc.get_browser()
form = browser.get_form(formname)
if form is None:
# try to find if one of the forms has <formname> as id
for form in browser._browser.forms():
# forms in cubicweb don't always have a name
if form.attrs.get('id') == formname:
break
else:
raise ValueError('could not find form named <%s>' % formname)
browser._browser.form = form
browser.submit(submit_button)
# missing actions: delete, copy, changeview