ver = StrictVersion('0.0.0')

    req_ver = StrictVersion('1.7.4')

    log.debug('Git executable: "%s" version %s detected: %s',

              settings.GIT_EXECUTABLE_PATH, ver, stdout)

    if stderr:

        log.warning('Error detecting git version: %r', stderr)

    elif ver < req_ver:

        log.warning('Kallithea detected git version %s, which is too old '

                    'for the system to function properly. '

                    'Please upgrade to version %s or later.' % (ver, req_ver))

    return ver

@decorator.decorator

def jsonify(func, *args, **kwargs):

    """Action decorator that formats output for JSON

    Given a function that will return content, this decorator will turn

    the result into JSON, with a content-type of 'application/json' and

    output it.

    """

    from pylons.decorators.util import get_pylons

    from kallithea.lib.compat import json

    pylons = get_pylons(args)

    pylons.response.headers['Content-Type'] = 'application/json; charset=utf-8'

    data = func(*args, **kwargs)

    if isinstance(data, (list, tuple)):

        msg = "JSON responses with Array envelopes are susceptible to " \

              "cross-site data leak attacks, see " \

              "http://wiki.pylonshq.com/display/pylonsfaq/Warnings"

        warnings.warn(msg, Warning, 2)

        log.warning(msg)

    log.debug("Returning JSON wrapped action output")

    return json.dumps(data, encoding='utf-8')

def conditional_cache(region, prefix, condition, func):

    """

    Conditional caching function use like::

        def _c(arg):

            #heavy computation function

            return data

        # denpending from condition the compute is wrapped in cache or not

        return compute(arg)

    :param region: name of cache region

    :param prefix: cache region prefix

    :param condition: condition for cache to be triggered, and return data cached

    :param func: wrapped heavy function to compute

    """

    wrapped = func

    if condition:

        log.debug('conditional_cache: True, wrapping call of '

                  'func: %s into %s region cache' % (region, func))

        wrapped = _cache_decorate((prefix,), None, None, region)(func)

    return wrapped

        if not revisions:

            return {}

        statuses = ChangesetStatus.query() \

            .filter(ChangesetStatus.repo == self) \

            .filter(ChangesetStatus.version == 0) \

            .filter(ChangesetStatus.revision.in_(revisions))

        grouped = {}

        for stat in statuses.all():

            pr_id = pr_nice_id = pr_repo = None

            if stat.pull_request:

                pr_id = stat.pull_request.pull_request_id

                pr_nice_id = PullRequest.make_nice_id(pr_id)

                pr_repo = stat.pull_request.other_repo.repo_name

            grouped[stat.revision] = [str(stat.status), stat.status_lbl,

                                      pr_id, pr_repo, pr_nice_id,

                                      stat.author]

        return grouped

    def _repo_size(self):

        from kallithea.lib import helpers as h

        log.debug('calculating repository size...')

        return h.format_byte_size(self.scm_instance.size)

    #==========================================================================

    # SCM CACHE INSTANCE

    #==========================================================================

    def set_invalidate(self):

        """

        Mark caches of this repo as invalid.

        """

        CacheInvalidation.set_invalidate(self.repo_name)

    def scm_instance_no_cache(self):

        return self.__get_instance()

    @property

    def scm_instance(self):

        import kallithea

        full_cache = str2bool(kallithea.CONFIG.get('vcs_full_cache'))

        if full_cache:

            return self.scm_instance_cached()

        return self.__get_instance()

    def scm_instance_cached(self, valid_cache_keys=None):

        @cache_region('long_term')

            return self.__get_instance()

        rn = self.repo_name

        valid = CacheInvalidation.test_and_set_valid(rn, None, valid_cache_keys=valid_cache_keys)

        if not valid:

            log.debug('Cache for %s invalidated, getting new object', rn)

            region_invalidate(_c, None, rn)

        else:

        return _c(rn)

    def __get_instance(self):

        repo_full_path = safe_str(self.repo_full_path)

        alias = get_scm(repo_full_path)[0]

        log.debug('Creating instance of %s repository from %s',

                  alias, self.repo_full_path)

        backend = get_backend(alias)

        if alias == 'hg':

            repo = backend(repo_full_path, create=False,

                           baseui=self._ui)

        else:

            repo = backend(repo_full_path, create=False)

        return repo

    def __json__(self):

        return dict(landing_rev = self.landing_rev)

class RepoGroup(Base, BaseModel):

    __tablename__ = 'groups'

    __table_args__ = (

        UniqueConstraint('group_name', 'group_parent_id'),

        CheckConstraint('group_id != group_parent_id'),

        _table_args_default_dict,

    )

    __mapper_args__ = {'order_by': 'group_name'}

    SEP = ' » '

    group_id = Column(Integer(), unique=True, primary_key=True)

    group_name = Column(Unicode(255), nullable=False, unique=True)

    group_parent_id = Column(Integer(), ForeignKey('groups.group_id'), nullable=True)

    group_description = Column(Unicode(10000), nullable=False)

    enable_locking = Column(Boolean(), nullable=False, default=False)

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

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

    repo_group_to_perm = relationship('UserRepoGroupToPerm', cascade='all', order_by='UserRepoGroupToPerm.group_to_perm_id')

    users_group_to_perm = relationship('UserGroupRepoGroupToPerm', cascade='all')

    parent_group = relationship('RepoGroup', remote_side=group_id)

    user = relationship('User')

    def __init__(self, group_name='', parent_group=None):

        self.group_name = group_name

        self.parent_group = parent_group

        """

        Delete all cache keys from database.

        Should only be run when all instances are down and all entries thus stale.

        """

        cls.query().delete()

        Session().commit()

    @classmethod

    def _get_cache_key(cls, key):

        """

        Wrapper for generating a unique cache key for this instance and "key".

        key must / will start with a repo_name which will be stored in .cache_args .

        """

        import kallithea

        prefix = kallithea.CONFIG.get('instance_id', '')

        return "%s%s" % (prefix, key)

    @classmethod

    def set_invalidate(cls, repo_name):

        """

        Mark all caches of a repo as invalid in the database.

        """

        inv_objs = Session().query(cls).filter(cls.cache_args == repo_name).all()

        log.debug('for repo %s got %s invalidation objects',

                  safe_str(repo_name), inv_objs)

        for inv_obj in inv_objs:

            log.debug('marking %s key for invalidation based on repo_name=%s',

                      inv_obj, safe_str(repo_name))

            Session().delete(inv_obj)

        Session().commit()

    @classmethod

    def test_and_set_valid(cls, repo_name, kind, valid_cache_keys=None):

        """

        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

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

        if inv_obj is None:

        elif inv_obj.cache_active:

            return True

        inv_obj.cache_active = True

        Session().add(inv_obj)

        try:

            Session().commit()

        except sqlalchemy.exc.IntegrityError:

            log.error('commit of CacheInvalidation failed - retrying')

            Session().rollback()

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

            if inv_obj is None:

                log.error('failed to create CacheInvalidation entry')

                # TODO: fail badly?

            # else: TOCTOU - another thread added the key at the same time; no further action required

        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'),

        Index('cc_pull_request_id_idx', 'pull_request_id'),

        _table_args_default_dict,

    )

    comment_id = Column(Integer(), unique=True, primary_key=True)

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

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

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

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

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

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

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

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

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

    author = relationship('User')

    repo = relationship('Repository')

    # status_change is frequently used directly in templates - make it a lazy

    # join to avoid fetching each related ChangesetStatus on demand.