Added licenses view helper functions.

lms/djangoapps/licenses/views.py

+import logging
+from itertools import groupby
+from collections import Iterable
+
+from django.db.models import Q
+
+from models import CourseSoftware, UserLicense
+
+log = logging.getLogger("mitx.licenses")
+
+
+def get_or_create_courses_licenses(user, courses):
+    user_licenses = get_courses_licenses(user, courses)
+
+    for software, license in user_licenses.iteritems():
+        if license is None:
+            user_licenses[software] = get_or_create_user_license(user, software)
+
+    log.info(user_licenses)
+
+    return user_licenses
+
+
+def get_courses_licenses(user, courses):
+    course_ids = set(course.id for course in courses)
+    all_software = CourseSoftware.objects.filter(course_id__in=course_ids)
+
+    user_licenses = dict.fromkeys(all_software, None)
+
+    assigned_licenses = UserLicense.objects.filter(software__in=all_software, user=user)
+    assigned_by_software = {lic.software:lic for lic in assigned_licenses}
+
+    for software, license in assigned_by_software.iteritems():
+        user_licenses[software] = license
+
+    return user_licenses
+
+
+def get_or_create_user_license(user, software):
+    license = None
+    try:
+        # Find a licenses associated with the user or with no user
+        # associated.
+        query = (Q(user__isnull=True) | Q(user=user)) & Q(software=software)
+
+        # TODO fix a race condition in this code when more than one
+        # user is getting a license assigned
+
+        license = UserLicense.objects.filter(query)[0]
+
+        if license.user is not user:
+            license.user = user
+            license.save()
+
+    except IndexError:
+        # TODO look if someone has unenrolled from the class and already has a serial number
+        log.error('No serial numbers available for {0}', software)
+
+
+    return license