--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/soc/logic/accounts.py	Sat Nov 15 03:12:33 2008 +0000
@@ -0,0 +1,129 @@
+#!/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.
+
+"""Basic Google Account and User (Model) query functions.
+"""
+
+__authors__ = [
+  '"Chen Lunpeng" <forever.clp@gmail.com>',
+  '"Todd Larsen" <tlarsen@google.com>',
+  ]
+
+
+from google.appengine.api import users
+
+from soc.logic import models
+from soc.logic import out_of_band
+
+import soc.models.user
+import soc.logic.models.user
+
+
+def isDeveloper(account=None):
+  """Returns True if a Google Account is a Developer with special privileges.
+  
+  Since it only works on the current logged-in user, if account matches the
+  current logged-in Google Account, the App Engine Users API function
+  user.is_current_user_admin() is checked.  If that returns False, or
+  account is not the currently logged-in user, the is_developer property of
+  the User entity corresponding to the Google Account is checked next.
+  
+  This solves the "chicken-and-egg" problem of no User entity having its
+  is_developer property set, but no one being able to set it.
+  
+  Args:
+    account: a Google Account (users.User) object; if not supplied,
+      the current logged-in user is checked
+  """
+
+  # Get the currently logged in user
+  current = users.get_current_user()
+
+  if not (account or current):
+    # no Google Account was supplied or is logged in, so an unspecified
+    # User is definitely *not* a Developer
+    return False
+
+  if (((not account) or (account == current))
+      and users.is_current_user_admin()):
+    # no account supplied, or current logged-in user, and that user is in the
+    # Administration->Developers list in the App Engine console
+    return True
+
+  if not account:
+    account = current
+
+  user = models.user.logic.getForFields({'account': account}, unique=True)
+
+  if not user:
+    # no User entity for this Google Account, and account is not the
+    # currently logged-in user, so there is no conclusive way to check the
+    # Administration->Developers list in the App Engine console
+    return False
+  
+  return user.is_developer
+
+
+def isAccountAvailable(new_account,
+                       existing_user=None, existing_key_name=None):
+  """Returns True if Google Account is available for use by existing User.
+  
+  Args:
+    new_account: a Google Account (users.User) object with a (possibly)
+      new email
+    existing_user: an existing User entity; default is None, in which case
+      existing_key_name is used to look up the User entity
+    existing_key_name: the key_name of an existing User entity, used
+      when existing_user is not supplied; default is None
+  """
+  if not existing_user:
+    existing_user = models.user.logic.getFromKeyName(existing_key_name)
+
+  if existing_user:
+    old_email = existing_user.account.email()
+  else:
+    old_email = None
+
+  if new_account.email().lower() == old_email.lower():
+    # "new" email is same as existing User wanting it, so it is "available"
+    return True
+  # else: "new" email truly is new to the existing User, so keep checking
+
+  if not models.user.logic.getForFields({'account': new_account},
+                                        unique=True):
+    # new email address also does not belong to any other User,
+    # so it is available
+    return True
+
+  # email does not already belong to this User, but to some other User
+  return False
+
+
+# TODO(tlarsen): make this generic for any Linkable and move elsewhere
+def getUserFromLinkNameOr404(link_name):
+  """Like getUserFromLinkName but expects to find a user
+
+  Raises:
+    out_of_band.ErrorResponse if no User entity is found
+  """
+  user = models.user.logic.getForFields({'link_name': link_name},
+                                        unique=True)
+
+  if user:
+    return user
+
+  raise out_of_band.ErrorResponse(
+      'There is no user with a "link name" of "%s".' % link_name, status=404)