:return False: if this directory is present

    """

    if os.path.isdir(os.path.join(base_path, repo_name)):

        return False

    return True

def check_repo(repo_name, base_path, verify=True):

    repo_path = os.path.join(base_path, repo_name)

    try:

        if not check_repo_fast(repo_name, base_path):

            return False

        r = hg.repository(ui.ui(), repo_path)

        if verify:

            hg.verify(r)

        #here we hnow that repo exists it was verified

        log.info('%s repo is already created', repo_name)

        return False

    except RepoError:

        #it means that there is no valid repo there...

        log.info('%s repo is free for creation', repo_name)

        return True

def ask_ok(prompt, retries=4, complaint='Yes or no, please!'):

    while True:

        ok = raw_input(prompt)

        if ok in ('y', 'ye', 'yes'):

            return True

        if ok in ('n', 'no', 'nop', 'nope'):

            return False

        retries = retries - 1

        if retries < 0:

            raise IOError

        print complaint

#propagated from mercurial documentation

ui_sections = ['alias', 'auth',

                'decode/encode', 'defaults',

                'diff', 'email',

                'extensions', 'format',

                'merge-patterns', 'merge-tools',

                'hooks', 'http_proxy',

                'smtp', 'patch',

                'paths', 'profiling',

                'server', 'trusted',

                'ui', 'web', ]

def make_ui(read_from='file', path=None, checkpaths=True):

    """A function that will read python rc files or database

    and make an mercurial ui object from read options

    :param path: path to mercurial config file

    :param checkpaths: check the path

    :param read_from: read from 'file' or 'db'

    """

    baseui = ui.ui()

    #clean the baseui object

    baseui._ocfg = config.config()

    baseui._ucfg = config.config()

    baseui._tcfg = config.config()

    if read_from == 'file':

        if not os.path.isfile(path):

            log.warning('Unable to read config file %s' % path)

            return False

        log.debug('reading hgrc from %s', path)

        cfg = config.config()

        cfg.read(path)

        for section in ui_sections:

            for k, v in cfg.items(section):

                log.debug('settings ui from file[%s]%s:%s', section, k, v)

                baseui.setconfig(section, k, v)

    elif read_from == 'db':

        sa = meta.Session()

        ret = sa.query(RhodeCodeUi)\

            .options(FromCache("sql_cache_short",

                               "get_hg_ui_settings")).all()

        hg_ui = ret

        for ui_ in hg_ui:

            if ui_.ui_active:

                log.debug('settings ui from db[%s]%s:%s', ui_.ui_section,

                          ui_.ui_key, ui_.ui_value)

                baseui.setconfig(ui_.ui_section, ui_.ui_key, ui_.ui_value)

        meta.Session.remove()

    return baseui

def set_rhodecode_config(config):

    """Updates pylons config with new settings from database

    :param config:

    """

    hgsettings = RhodeCodeSettings.get_app_settings()

    for k, v in hgsettings.items():

        config[k] = v

def invalidate_cache(cache_key, *args):

    """Puts cache invalidation task into db for

    further global cache invalidation

    """

    from rhodecode.model.scm import ScmModel

    if cache_key.startswith('get_repo_cached_'):

        name = cache_key.split('get_repo_cached_')[-1]

        ScmModel().mark_for_invalidation(name)

class EmptyChangeset(BaseChangeset):

    """

    An dummy empty changeset. It's possible to pass hash when creating

    an EmptyChangeset

    """

    def __init__(self, cs='0' * 40, repo=None):

        self._empty_cs = cs

        self.revision = -1

        self.message = ''

        self.author = ''

        self.date = ''

        self.repository = repo

    @LazyProperty

    def raw_id(self):

        """Returns raw string identifying this changeset, useful for web

        representation.

        """

        return self._empty_cs

    @LazyProperty

    def short_id(self):

        return self.raw_id[:12]

    def get_file_changeset(self, path):

        return self

    def get_file_content(self, path):

        return u''

    def get_file_size(self, path):

        return 0

def map_groups(groups):

    """Checks for groups existence, and creates groups structures.

    It returns last group in structure

    :param groups: list of groups structure

    """

    sa = meta.Session()

    parent = None

    group = None

    for lvl, group_name in enumerate(groups[:-1]):

        group = sa.query(Group).filter(Group.group_name == group_name).scalar()

        if group is None:

            group = Group(group_name, parent)

            sa.add(group)

            sa.commit()

        parent = group

    return group

def repo2db_mapper(initial_repo_list, remove_obsolete=False):

    """maps all repos given in initial_repo_list, non existing repositories

    are created, if remove_obsolete is True it also check for db entries

    that are not in initial_repo_list and removes them.

    :param initial_repo_list: list of repositories found by scanning methods

    :param remove_obsolete: check for obsolete entries in database

    """

    sa = meta.Session()

    rm = RepoModel()

    user = sa.query(User).filter(User.admin == True).first()

    added = []

    for name, repo in initial_repo_list.items():

        if not rm.get_by_repo_name(name, cache=False):

            log.info('repository %s not found creating default', name)

            added.append(name)

            form_data = {

                         'repo_name': name,

                         'repo_name_full': name,

                         'repo_type': repo.alias,

                         'description': repo.description \

                            if repo.description != 'unknown' else \

                                        '%s repository' % name,

                         'private': False,

                         'group_id': getattr(group, 'group_id', None)

                         }

            rm.create(form_data, user, just_db=True)

    removed = []

    if remove_obsolete:

        #remove from database those repositories that are not in the filesystem

        for repo in sa.query(Repository).all():

            if repo.repo_name not in initial_repo_list.keys():

                removed.append(repo.repo_name)

                sa.delete(repo)

                sa.commit()

    return added, removed

#set cache regions for beaker so celery can utilise it

def add_cache(settings):

    cache_settings = {'regions': None}

    for key in settings.keys():

        for prefix in ['beaker.cache.', 'cache.']:

            if key.startswith(prefix):

                name = key.split(prefix)[1].strip()

                cache_settings[name] = settings[key].strip()

    if cache_settings['regions']:

        for region in cache_settings['regions'].split(','):

            region = region.strip()

            region_settings = {}

            for key, value in cache_settings.items():

                if key.startswith(region):

                    region_settings[key.split('.')[1]] = value

            region_settings['expire'] = int(region_settings.get('expire',

                                                                60))

            region_settings.setdefault('lock_dir',

                                       cache_settings.get('lock_dir'))

            region_settings.setdefault('data_dir',

                                       cache_settings.get('data_dir'))

            if 'type' not in region_settings:

                region_settings['type'] = cache_settings.get('type',

                                                             'memory')

            beaker.cache.cache_regions[region] = region_settings

def get_current_revision():

    """Returns tuple of (number, id) from repository containing this package

    or None if repository could not be found.

    """

    try:

        from vcs import get_repo

        from vcs.utils.helpers import get_scm

        from vcs.exceptions import RepositoryError, VCSError

        repopath = os.path.join(os.path.dirname(__file__), '..', '..')

        scm = get_scm(repopath)[0]

        repo = get_repo(path=repopath, alias=scm)

        tip = repo.get_changeset()

        return (tip.revision, tip.short_id)

    except (ImportError, RepositoryError, VCSError), err:

        logging.debug("Cannot retrieve rhodecode's revision. Original error "

                      "was: %s" % err)

        return None

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

# TEST FUNCTIONS AND CREATORS

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

def create_test_index(repo_location, config, full_index):

    """

    Makes default test index

    :param config: test config

    :param full_index:

    """

    from rhodecode.lib.indexers.daemon import WhooshIndexingDaemon

    from rhodecode.lib.pidlock import DaemonLock, LockHeld

    repo_location = repo_location

    index_location = os.path.join(config['app_conf']['index_dir'], 'index')

    if not os.path.exists(index_location):

        os.makedirs(index_location)

    try:

        l = DaemonLock(file=jn(dn(index_location), 'make_index.lock'))

        WhooshIndexingDaemon(index_location=index_location,

                             repo_location=repo_location)\

            .run(full_index=full_index)

        l.release()

    except LockHeld:

        pass

def create_test_env(repos_test_path, config):

    """Makes a fresh database and

    install test repository into tmp dir

    """

    from rhodecode.lib.db_manage import DbManage

    from rhodecode.tests import HG_REPO, GIT_REPO, NEW_HG_REPO, NEW_GIT_REPO, \

        HG_FORK, GIT_FORK, TESTS_TMP_PATH

    import tarfile

    import shutil

    from os.path import dirname as dn, join as jn, abspath

    log = logging.getLogger('TestEnvCreator')

    # create logger

    log.setLevel(logging.DEBUG)

    log.propagate = True

    # create console handler and set level to debug

    ch = logging.StreamHandler()

    ch.setLevel(logging.DEBUG)

    # create formatter

    formatter = logging.Formatter("%(asctime)s - %(name)s -"

                                  " %(levelname)s - %(message)s")

    # add formatter to ch

    ch.setFormatter(formatter)

    # add ch to logger

    log.addHandler(ch)

    #PART ONE create db

    dbconf = config['sqlalchemy.db1.url']

    log.debug('making test db %s', dbconf)

    # create test dir if it doesn't exist

    if not os.path.isdir(repos_test_path):

        log.debug('Creating testdir %s' % repos_test_path)

        os.makedirs(repos_test_path)

    dbmanage = DbManage(log_sql=True, dbconf=dbconf, root=config['here'],

                        tests=True)

    dbmanage.create_tables(override=True)

    dbmanage.create_settings(dbmanage.config_prompt(repos_test_path))

    dbmanage.create_default_user()

    dbmanage.admin_prompt()

    dbmanage.create_permissions()

    dbmanage.populate_default_permissions()

    #PART TWO make test repo

    log.debug('making test vcs repositories')

    #remove old one from previos tests

    for r in [HG_REPO, GIT_REPO, NEW_HG_REPO, NEW_GIT_REPO, HG_FORK, GIT_FORK]:

        if os.path.isdir(jn(TESTS_TMP_PATH, r)):

            log.debug('removing %s', r)

            shutil.rmtree(jn(TESTS_TMP_PATH, r))

    idx_path = config['app_conf']['index_dir']

    data_path = config['app_conf']['cache_dir']

    #clean index and data

    if idx_path and os.path.exists(idx_path):

        log.debug('remove %s' % idx_path)

        shutil.rmtree(idx_path)

    if data_path and os.path.exists(data_path):

        log.debug('remove %s' % data_path)

        shutil.rmtree(data_path)

    #CREATE DEFAULT HG REPOSITORY

    cur_dir = dn(dn(abspath(__file__)))

    tar = tarfile.open(jn(cur_dir, 'tests', "vcs_test_hg.tar.gz"))

    tar.extractall(jn(TESTS_TMP_PATH, HG_REPO))

    tar.close()

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

# PASTER COMMANDS

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

class BasePasterCommand(Command):

    """

    Abstract Base Class for paster commands.

    The celery commands are somewhat aggressive about loading

    celery.conf, and since our module sets the `CELERY_LOADER`

    environment variable to our loader, we have to bootstrap a bit and

    make sure we've had a chance to load the pylons config off of the

    command line, otherwise everything fails.