"""

        Mark this cache key as active and currently cached.

        Return True if the existing cache registration still was valid.

        Return False to indicate that it had been invalidated and caches should be refreshed.

        """

        key = (repo_name + '_' + kind) if kind else repo_name

        cache_key = cls._get_cache_key(key)

        if valid_cache_keys and cache_key in valid_cache_keys:

            return True

        try:

            inv_obj = cls.query().filter(cls.cache_key == cache_key).scalar()

            if not inv_obj:

                inv_obj = CacheInvalidation(cache_key, repo_name)

            was_valid = inv_obj.cache_active

            inv_obj.cache_active = True

            Session().add(inv_obj)

            Session().commit()

            return was_valid

        except Exception:

            log.error(traceback.format_exc())

            Session().rollback()

            return False

    @classmethod

    def get_valid_cache_keys(cls):

        """

        Return opaque object with information of which caches still are valid

        and can be used without checking for invalidation.

        """

        return set(inv_obj.cache_key for inv_obj in cls.query().filter(cls.cache_active).all())

class ChangesetComment(Base, BaseModel):

    __tablename__ = 'changeset_comments'

    __table_args__ = (

        Index('cc_revision_idx', 'revision'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8', 'sqlite_autoincrement': True},

    )

    comment_id = Column('comment_id', Integer(), nullable=False, primary_key=True)

    repo_id = Column('repo_id', Integer(), ForeignKey('repositories.repo_id'), nullable=False)

    revision = Column('revision', String(40), nullable=True)

    pull_request_id = Column("pull_request_id", Integer(), ForeignKey('pull_requests.pull_request_id'), nullable=True)

    line_no = Column('line_no', Unicode(10), nullable=True)

    hl_lines = Column('hl_lines', Unicode(512), nullable=True)

    f_path = Column('f_path', Unicode(1000), nullable=True)

    user_id = Column('user_id', Integer(), ForeignKey('users.user_id'), nullable=False)

    text = Column('text', UnicodeText(25000), nullable=False)

    created_on = Column('created_on', DateTime(timezone=False), nullable=False, default=datetime.datetime.now)

    modified_at = Column('modified_at', DateTime(timezone=False), nullable=False, default=datetime.datetime.now)

    author = relationship('User', lazy='joined')

    repo = relationship('Repository')

    status_change = relationship('ChangesetStatus', cascade="all, delete, delete-orphan")

    pull_request = relationship('PullRequest')

    @classmethod

    def get_users(cls, revision=None, pull_request_id=None):

        """

        Returns user associated with this ChangesetComment. ie those

        who actually commented

        :param cls:

        :param revision:

        """

        q = Session().query(User)\

                .join(ChangesetComment.author)

        if revision:

            q = q.filter(cls.revision == revision)

        elif pull_request_id:

            q = q.filter(cls.pull_request_id == pull_request_id)

        return q.all()

class ChangesetStatus(Base, BaseModel):

    __tablename__ = 'changeset_statuses'

    __table_args__ = (

        Index('cs_revision_idx', 'revision'),

        Index('cs_version_idx', 'version'),

        UniqueConstraint('repo_id', 'revision', 'version'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8', 'sqlite_autoincrement': True}

    )

    STATUS_NOT_REVIEWED = DEFAULT = 'not_reviewed'

    STATUS_APPROVED = 'approved'

    STATUS_REJECTED = 'rejected'

    STATUS_UNDER_REVIEW = 'under_review'

    STATUSES = [

        (STATUS_NOT_REVIEWED, _("Not Reviewed")),  # (no icon) and default

        (STATUS_APPROVED, _("Approved")),

        (STATUS_REJECTED, _("Rejected")),

        (STATUS_UNDER_REVIEW, _("Under Review")),

    ]

    changeset_status_id = Column('changeset_status_id', Integer(), nullable=False, primary_key=True)

    repo_id = Column('repo_id', Integer(), ForeignKey('repositories.repo_id'), nullable=False)

    user_id = Column("user_id", Integer(), ForeignKey('users.user_id'), nullable=False, unique=None)

    revision = Column('revision', String(40), nullable=False)

    status = Column('status', String(128), nullable=False, default=DEFAULT)

    changeset_comment_id = Column('changeset_comment_id', Integer(), ForeignKey('changeset_comments.comment_id'))

    modified_at = Column('modified_at', DateTime(), nullable=False, default=datetime.datetime.now)

    version = Column('version', Integer(), nullable=False, default=0)

    pull_request_id = Column("pull_request_id", Integer(), ForeignKey('pull_requests.pull_request_id'), nullable=True)

    author = relationship('User', lazy='joined')

    repo = relationship('Repository')

    comment = relationship('ChangesetComment', lazy='joined')

    pull_request = relationship('PullRequest')

    def __unicode__(self):

        return u"<%s('%s:%s')>" % (

            self.__class__.__name__,

            self.status, self.author

        )

    @classmethod

    def get_status_lbl(cls, value):

        return dict(cls.STATUSES).get(value)

    @property

    def status_lbl(self):

        return ChangesetStatus.get_status_lbl(self.status)

class PullRequest(Base, BaseModel):

    __tablename__ = 'pull_requests'

    __table_args__ = (

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8', 'sqlite_autoincrement': True},

    )

    # values for .status

    STATUS_NEW = u'new'

    STATUS_CLOSED = u'closed'

    pull_request_id = Column('pull_request_id', Integer(), nullable=False, primary_key=True)

    title = Column('title', Unicode(256), nullable=True)

    description = Column('description', UnicodeText(10240), nullable=True)

    status = Column('status', Unicode(256), nullable=False, default=STATUS_NEW) # only for closedness, not approve/reject/etc

    created_on = Column('created_on', DateTime(timezone=False), nullable=False, default=datetime.datetime.now)

    updated_on = Column('updated_on', DateTime(timezone=False), nullable=False, default=datetime.datetime.now)

    user_id = Column("user_id", Integer(), ForeignKey('users.user_id'), nullable=False, unique=None)

    _revisions = Column('revisions', UnicodeText(20500))  # 500 revisions max

    org_repo_id = Column('org_repo_id', Integer(), ForeignKey('repositories.repo_id'), nullable=False)

    org_ref = Column('org_ref', Unicode(256), nullable=False)

    other_repo_id = Column('other_repo_id', Integer(), ForeignKey('repositories.repo_id'), nullable=False)

    other_ref = Column('other_ref', Unicode(256), nullable=False)

    @hybrid_property

    def revisions(self):

        return self._revisions.split(':')

    @revisions.setter

    def revisions(self, val):

        self._revisions = ':'.join(val)

    @property

    def org_ref_parts(self):

        return self.org_ref.split(':')

    @property

    def other_ref_parts(self):

        return self.other_ref.split(':')

    author = relationship('User', lazy='joined')

    reviewers = relationship('PullRequestReviewers',

                             cascade="all, delete, delete-orphan")

    org_repo = relationship('Repository', primaryjoin='PullRequest.org_repo_id==Repository.repo_id')

    other_repo = relationship('Repository', primaryjoin='PullRequest.other_repo_id==Repository.repo_id')

    statuses = relationship('ChangesetStatus')

    comments = relationship('ChangesetComment',

                             cascade="all, delete, delete-orphan")

    def is_closed(self):

        return self.status == self.STATUS_CLOSED

    @property

    def last_review_status(self):

        return str(self.statuses[-1].status) if self.statuses else ''

    def __json__(self):

        return dict(

            revisions=self.revisions

        )

    def url(self, **kwargs):

        canonical = kwargs.pop('canonical', None)

        import kallithea.lib.helpers as h

        b = self.org_ref_parts[1]

        if b != self.other_ref_parts[1]:

        kwargs['extra'] = urlreadable(s)

        if canonical:

            return h.canonical_url('pullrequest_show', repo_name=self.other_repo.repo_name,

                                   pull_request_id=self.pull_request_id, **kwargs)

        return h.url('pullrequest_show', repo_name=self.other_repo.repo_name,

                     pull_request_id=self.pull_request_id, **kwargs)

class PullRequestReviewers(Base, BaseModel):

    __tablename__ = 'pull_request_reviewers'

    __table_args__ = (

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8', 'sqlite_autoincrement': True},

    )

    def __init__(self, user=None, pull_request=None):

        self.user = user

        self.pull_request = pull_request

    pull_requests_reviewers_id = Column('pull_requests_reviewers_id', Integer(), nullable=False, primary_key=True)

    pull_request_id = Column("pull_request_id", Integer(), ForeignKey('pull_requests.pull_request_id'), nullable=False)

    user_id = Column("user_id", Integer(), ForeignKey('users.user_id'), nullable=True)

    user = relationship('User')

    pull_request = relationship('PullRequest')

class Notification(Base, BaseModel):

    __tablename__ = 'notifications'

    __table_args__ = (

        Index('notification_type_idx', 'type'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8', 'sqlite_autoincrement': True},

    )

    TYPE_CHANGESET_COMMENT = u'cs_comment'

    TYPE_MESSAGE = u'message'

    TYPE_MENTION = u'mention'

    TYPE_REGISTRATION = u'registration'

    TYPE_PULL_REQUEST = u'pull_request'

    TYPE_PULL_REQUEST_COMMENT = u'pull_request_comment'

    notification_id = Column('notification_id', Integer(), nullable=False, primary_key=True)

    subject = Column('subject', Unicode(512), nullable=True)

    body = Column('body', UnicodeText(50000), nullable=True)

    created_by = Column("created_by", Integer(), ForeignKey('users.user_id'), nullable=True)

    created_on = Column('created_on', DateTime(timezone=False), nullable=False, default=datetime.datetime.now)

    type_ = Column('type', Unicode(256))

    created_by_user = relationship('User')

    notifications_to_users = relationship('UserNotification', lazy='joined',

                                          cascade="all, delete, delete-orphan")

    @property

    def recipients(self):

        return [x.user for x in UserNotification.query()\

                .filter(UserNotification.notification == self)\

                .order_by(UserNotification.user_id.asc()).all()]

    @classmethod

    def create(cls, created_by, subject, body, recipients, type_=None):

        if type_ is None:

            type_ = Notification.TYPE_MESSAGE

        notification = cls()

        notification.created_by_user = created_by

        notification.subject = subject

        notification.body = body

        notification.type_ = type_

        notification.created_on = datetime.datetime.now()

        for u in recipients:

            assoc = UserNotification()

            assoc.notification = notification

            u.notifications.append(assoc)

        Session().add(notification)

        return notification

    @property

    def description(self):

        from kallithea.model.notification import NotificationModel

        return NotificationModel().make_description(self)

class UserNotification(Base, BaseModel):

    __tablename__ = 'user_to_notification'

    __table_args__ = (

        UniqueConstraint('user_id', 'notification_id'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8', 'sqlite_autoincrement': True}

    )

    user_id = Column('user_id', Integer(), ForeignKey('users.user_id'), primary_key=True)

    notification_id = Column("notification_id", Integer(), ForeignKey('notifications.notification_id'), primary_key=True)

    read = Column('read', Boolean, default=False)

    sent_on = Column('sent_on', DateTime(timezone=False), nullable=True, unique=None)

    user = relationship('User', lazy="joined")

    notification = relationship('Notification', lazy="joined",

                                order_by=lambda: Notification.created_on.desc(),)

    def mark_as_read(self):

        self.read = True

        Session().add(self)

class Gist(Base, BaseModel):

    __tablename__ = 'gists'

    __table_args__ = (

        Index('g_gist_access_id_idx', 'gist_access_id'),

        Index('g_created_on_idx', 'created_on'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8', 'sqlite_autoincrement': True}

    )

    GIST_PUBLIC = u'public'

    GIST_PRIVATE = u'private'

    DEFAULT_FILENAME = u'gistfile1.txt'

    gist_id = Column('gist_id', Integer(), primary_key=True)

    gist_access_id = Column('gist_access_id', Unicode(250))

    gist_description = Column('gist_description', UnicodeText(1024))

    gist_owner = Column('user_id', Integer(), ForeignKey('users.user_id'), nullable=True)

    gist_expires = Column('gist_expires', Float(53), nullable=False)

    gist_type = Column('gist_type', Unicode(128), nullable=False)

    created_on = Column('created_on', DateTime(timezone=False), nullable=False, default=datetime.datetime.now)

    modified_at = Column('modified_at', DateTime(timezone=False), nullable=False, default=datetime.datetime.now)

    owner = relationship('User')

    def __repr__(self):

        return '<Gist:[%s]%s>' % (self.gist_type, self.gist_access_id)

    @classmethod

    def get_or_404(cls, id_):

        res = cls.query().filter(cls.gist_access_id == id_).scalar()

        if not res:

            raise HTTPNotFound

        return res

    @classmethod

    def get_by_access_id(cls, gist_access_id):

        return cls.query().filter(cls.gist_access_id == gist_access_id).scalar()

    def gist_url(self):

        import kallithea

        alias_url = kallithea.CONFIG.get('gist_alias_url')

        if alias_url:

            return alias_url.replace('{gistid}', self.gist_access_id)

        import kallithea.lib.helpers as h

        return h.canonical_url('gist', gist_id=self.gist_access_id)

    @classmethod

    def base_path(cls):

        """

        Returns base path where all gists are stored

        :param cls:

        """

        from kallithea.model.gist import GIST_STORE_LOC

        q = Session().query(Ui)\

            .filter(Ui.ui_key == URL_SEP)

        q = q.options(FromCache("sql_cache_short", "repository_repo_path"))

        return os.path.join(q.one().ui_value, GIST_STORE_LOC)

    def get_api_data(self):

        """

        Common function for generating gist related data for API

        """

        gist = self

        data = dict(

            gist_id=gist.gist_id,

            type=gist.gist_type,

            access_id=gist.gist_access_id,

            description=gist.gist_description,

            url=gist.gist_url(),

            expires=gist.gist_expires,

            created_on=gist.created_on,

        )

        return data

    def __json__(self):

        data = dict(

        )

        data.update(self.get_api_data())

        return data

    ## SCM functions

    @property

    def scm_instance(self):

        from kallithea.lib.vcs import get_repo

        base_path = self.base_path()

        return get_repo(os.path.join(*map(safe_str,

                                          [base_path, self.gist_access_id])))