.filter(UserFollowing.user_id == user_id).scalar()

        if f is not None:

            try:

                Session().delete(f)

                action_logger(UserTemp(user_id),

                              'stopped_following_repo',

                              RepoTemp(follow_repo_id))

                return

            except Exception:

                log.error(traceback.format_exc())

                raise

        try:

            f = UserFollowing()

            f.user_id = user_id

            f.follows_repository_id = follow_repo_id

            Session().add(f)

            action_logger(UserTemp(user_id),

                          'started_following_repo',

                          RepoTemp(follow_repo_id))

        except Exception:

            log.error(traceback.format_exc())

            raise

    def toggle_following_user(self, follow_user_id, user_id):

        f = UserFollowing.query() \

            .filter(UserFollowing.follows_user_id == follow_user_id) \

            .filter(UserFollowing.user_id == user_id).scalar()

        if f is not None:

            try:

                Session().delete(f)

                return

            except Exception:

                log.error(traceback.format_exc())

                raise

        try:

            f = UserFollowing()

            f.user_id = user_id

            f.follows_user_id = follow_user_id

            Session().add(f)

        except Exception:

            log.error(traceback.format_exc())

            raise

        r = Repository.query() \

            .filter(Repository.repo_name == repo_name).scalar()

        f = UserFollowing.query() \

            .filter(UserFollowing.follows_repository == r) \

            .filter(UserFollowing.user_id == user_id).scalar()

        return f is not None

        u = User.get_by_username(username)

        f = UserFollowing.query() \

            .filter(UserFollowing.follows_user == u) \

            .filter(UserFollowing.user_id == user_id).scalar()

        return f is not None

    def get_followers(self, repo):

        repo = Repository.guess_instance(repo)

        return UserFollowing.query() \

                .filter(UserFollowing.follows_repository == repo).count()

    def get_forks(self, repo):

        repo = Repository.guess_instance(repo)

        return Repository.query() \

                .filter(Repository.fork == repo).count()

    def get_pull_requests(self, repo):

        repo = Repository.guess_instance(repo)

        return PullRequest.query() \

                .filter(PullRequest.other_repo == repo) \

                .filter(PullRequest.status != PullRequest.STATUS_CLOSED).count()

    def mark_as_fork(self, repo, fork, user):

        repo = self.__get_repo(repo)

        fork = self.__get_repo(fork)

        if fork and repo.repo_id == fork.repo_id:

            raise Exception("Cannot set repository as fork of itself")

        if fork and repo.repo_type != fork.repo_type:

            raise RepositoryError("Cannot set repository as fork of repository with other type")

        repo.fork = fork

        return repo

    def _handle_push(self, repo, username, ip_addr, action, repo_name, revisions):

        """

        Handle that the repository has changed.

        Adds an action log entry with the new revisions, and the head revision

        cache and in-memory caches are invalidated/updated.

        :param username: username who pushes

        :param action: push/push_local/push_remote

        :param repo_name: name of repo

        :param revisions: list of revisions that we pushed

        """

        def_user = User.get_default_user()

        for p in def_user.user_perms:

            if p.permission.permission_name.startswith('usergroup.'):

                default_perm = p.permission.permission_name

                break

        user_group_to_perm = UserUserGroupToPerm()

        user_group_to_perm.permission = Permission.get_by_key(default_perm)

        user_group_to_perm.user_group = user_group

        user_group_to_perm.user_id = def_user.user_id

        Session().add(user_group_to_perm)

        return user_group_to_perm

    def _update_permissions(self, user_group, perms_new=None,

                            perms_updates=None):

        from kallithea.lib.auth import HasUserGroupPermissionLevel

        if not perms_new:

            perms_new = []

        if not perms_updates:

            perms_updates = []

        # update permissions

        for member, perm, member_type in perms_updates:

            if member_type == 'user':

                # this updates existing one

                self.grant_user_permission(

                    user_group=user_group, user=member, perm=perm

                )

            else:

                # check if we have permissions to alter this usergroup's access

                if HasUserGroupPermissionLevel('read')(member):

                    self.grant_user_group_permission(

                        target_user_group=user_group, user_group=member, perm=perm

                    )

        # set new permissions

        for member, perm, member_type in perms_new:

            if member_type == 'user':

                self.grant_user_permission(

                    user_group=user_group, user=member, perm=perm

                )

            else:

                # check if we have permissions to alter this usergroup's access

                if HasUserGroupPermissionLevel('read')(member):

                    self.grant_user_group_permission(

                        target_user_group=user_group, user_group=member, perm=perm

                    )

        return UserGroup.get(user_group_id)

    def get_group(self, user_group):

        return UserGroup.guess_instance(user_group)

    def get_by_name(self, name, cache=False, case_insensitive=False):

        return UserGroup.get_by_group_name(name, cache=cache, case_insensitive=case_insensitive)

    def create(self, name, description, owner, active=True, group_data=None):

        try:

            new_user_group = UserGroup()

            new_user_group.owner = User.guess_instance(owner)

            new_user_group.users_group_name = name

            new_user_group.user_group_description = description

            new_user_group.users_group_active = active

            if group_data:

                new_user_group.group_data = group_data

            Session().add(new_user_group)

            self._create_default_perms(new_user_group)

            self.grant_user_permission(user_group=new_user_group,

                                       user=owner, perm='usergroup.admin')

            return new_user_group

        except Exception:

            log.error(traceback.format_exc())

            raise

    def update(self, user_group, form_data):

        try:

            user_group = UserGroup.guess_instance(user_group)

            for k, v in form_data.items():

                if k == 'users_group_members':

                    members_list = []

                    if v:

                        v = [v] if isinstance(v, basestring) else v

                        for u_id in set(v):

                            member = UserGroupMember(user_group.users_group_id, u_id)

                            members_list.append(member)

                            Session().add(member)

                    user_group.members = members_list

                setattr(user_group, k, v)

            # Flush to make db assign users_group_member_id to newly

            # created UserGroupMembers.

            Session().flush()