# HG changeset patch
# User Pawel Solyga <Pawel.Solyga@gmail.com>
# Date 1222899146 0
# Node ID 12f4f7d16face06d3eb0acc449c8e1cd31f49fe3
# Parent  878f9ec9dd07fc8f8247490ce8e0ec63c250c5ba
Add Sponsor logic functions.

Patch by: Pawel Solyga
Review by: to-be-reviewed

diff -r 878f9ec9dd07 -r 12f4f7d16fac app/soc/logic/sponsor.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/soc/logic/sponsor.py	Wed Oct 01 22:12:26 2008 +0000
@@ -0,0 +1,140 @@
+#!/usr/bin/python2.5
+#
+# Copyright 2008 the Melange authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Sponsor (Model) query functions.
+"""
+
+__authors__ = [
+  '"Pawel Solyga" <pawel.solyga@gmail.com>',
+  ]
+
+
+from soc.logic import key_name
+from soc.logic import out_of_band
+
+import soc.models.sponsor
+import soc.logic.model
+
+
+def doesLinkNameExist(link_name=None):
+  """Returns True if link name exists in the Datastore.
+
+  Args:
+    link_name: link name used in URLs to identify Sponsor
+  """
+  if getSponsorFromLinkName(link_name):
+    return True
+  else:
+    return False
+
+
+def getSponsorFromLinkName(link_name):
+  """Returns Sponsor entity for a given link name, or None if not found.  
+    
+  Args:
+    link_name: a link name of the Sponsor that uniquely identifies it
+  """
+  # lookup by Sponsor key name
+  sponsor_key_name = getSponsorKeyNameForLinkName(link_name)
+  
+  if key_name:
+    sponsor = soc.models.sponsor.Sponsor.get_by_key_name(sponsor_key_name)
+  else:
+    sponsor = None
+  
+  return sponsor
+
+
+def getSponsorIfLinkName(link_name=None):
+  """Returns Sponsor entity for supplied link name if one exists.
+
+  Args:
+    link_name: a link name of the Sponsor that uniquely identifies it
+
+  Returns:
+    * None if link name is false.
+    * Sponsor entity for supplied linkname
+
+  Raises:
+    out_of_band.ErrorResponse if link name is not false, but no Sponsor entity
+    with the supplied link name exists in the Datastore
+  """
+  if not link_name:
+    # exit without error, to let view know that link_name was not supplied
+    return None
+
+  linkname_sponsor = getSponsorFromLinkName(link_name=link_name)
+
+  if linkname_sponsor:
+    # a Sponsor exist for this linkname, so return that Sponsor entity
+    return linkname_sponsor
+
+  # else: a linkname was supplied, but there is no Sponsor that has it
+  raise out_of_band.ErrorResponse(
+      'There is no sponsor with a "link name" of "%s".' % link_name, status=404)
+
+
+def getSponsorKeyNameForLinkName(link_name):
+  """Return a Datastore key_name for a Sponsor from the link name.
+  
+  Args:
+    link_name: a link name of the Sponsor that uniquely identifies it
+  """
+  if not link_name:
+    return None
+
+  return key_name.nameSponsor(link_name)
+
+
+def getSponsorsForOffsetAndLimit(offset=0, limit=0):
+  """Returns Sponsors entities for given offset and limit or None if not found.
+
+  Args:
+    offset: offset in entities list which defines first entity to return
+    limit: max amount of entities to return
+  """
+  query = soc.models.sponsor.Sponsor.all()
+  
+  # Fetch one more to see if there should be a 'next' link
+  return query.fetch(limit+1, offset)
+
+
+def updateOrCreateSponsorFromLinkName(sponsor_link_name, **sponsor_properties):
+  """Update existing Sponsor entity, or create new one with supplied properties.
+
+  Args:
+    sponsor_name: a linkname of the Sponsor that uniquely identifies it
+    **sponsor_properties: keyword arguments that correspond to Sponsor entity
+      properties and their values
+
+  Returns:
+    the Sponsor entity corresponding to the path, with any supplied
+    properties changed, or a new Sponsor entity now associated with the 
+    supplied path and properties.
+  """
+  # attempt to retrieve the existing Sponsor
+  sponsor = getSponsorFromLinkName(sponsor_link_name)
+
+  if not sponsor:
+    # sponsor did not exist, so create one in a transaction
+    sponsor_key_name = getSponsorKeyNameForLinkName(sponsor_link_name)
+    sponsor = soc.models.sponsor.Sponsor.get_or_insert(
+      sponsor_key_name, **sponsor_properties)
+
+  # there is no way to be sure if get_or_insert() returned a new Sponsor or
+  # got an existing one due to a race, so update with sponsor_properties anyway,
+  # in a transaction
+  return soc.logic.model.updateModelProperties(sponsor, **sponsor_properties)
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