:return True: if given path is a valid repository

    """

    # TODO: paranoid security checks?

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

    try:

        scm_ = get_scm(full_path)

        if scm:

            return scm_[0] == scm

        return True

    except VCSError:

        return False

def is_valid_repo_group(repo_group_name, base_path, skip_path_check=False):

    """

    Returns True if given path is a repository group False otherwise

    :param repo_name:

    :param base_path:

    """

    full_path = os.path.join(base_path, repo_group_name)

    # check if it's not a repo

    if is_valid_repo(repo_group_name, base_path):

        return False

    try:

        # we need to check bare git repos at higher level

        # since we might match branches/hooks/info/objects or possible

        # other things inside bare git repo

        get_scm(os.path.dirname(full_path))

        return False

    except VCSError:

        pass

    # check if it's a valid path

    if skip_path_check or os.path.isdir(full_path):

        return True

    return False

def make_ui(repo_path=None):

    """

    Create an Mercurial 'ui' object based on database Ui settings, possibly

    augmenting with content from a hgrc file.

    """

    baseui = mercurial.ui.ui()

    # clean the baseui object

    baseui._ocfg = mercurial.config.config()

    baseui._ucfg = mercurial.config.config()

    baseui._tcfg = mercurial.config.config()

    sa = meta.Session()

    for ui_ in sa.query(Ui).order_by(Ui.ui_section, Ui.ui_key):

        if ui_.ui_active:

            log.debug('config from db: [%s] %s=%r', ui_.ui_section,

                      ui_.ui_key, ui_.ui_value)

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

                             b'' if ui_.ui_value is None else safe_bytes(ui_.ui_value))

    # force set push_ssl requirement to False, Kallithea handles that

    baseui.setconfig(b'web', b'push_ssl', False)

    baseui.setconfig(b'web', b'allow_push', b'*')

    # prevent interactive questions for ssh password / passphrase

    ssh = baseui.config(b'ui', b'ssh', default=b'ssh')

    baseui.setconfig(b'ui', b'ssh', b'%s -oBatchMode=yes -oIdentitiesOnly=yes' % ssh)

    # push / pull hooks

    baseui.setconfig(b'hooks', b'changegroup.kallithea_log_push_action', b'python:kallithea.lib.hooks.log_push_action')

    baseui.setconfig(b'hooks', b'outgoing.kallithea_log_pull_action', b'python:kallithea.lib.hooks.log_pull_action')

    if repo_path is not None:

        # Note: MercurialRepository / mercurial.localrepo.instance will do this too, so it will always be possible to override db settings or what is hardcoded above

        baseui.readconfig(repo_path)

    assert baseui.plain()  # set by hgcompat.monkey_do (invoked from import of vcs.backends.hg) to minimize potential impact of loading config files

    return baseui

def set_app_settings(config):

    """

    Updates app config with new settings from database

    :param config:

    """

    hgsettings = Setting.get_app_settings()

    for k, v in hgsettings.items():

        config[k] = v

    config['base_path'] = Ui.get_repos_location()

def set_vcs_config(config):

    """

    Patch VCS config with some Kallithea specific stuff

    :param config: kallithea.CONFIG

    """

    settings.BACKENDS = {

        'hg': 'kallithea.lib.vcs.backends.hg.MercurialRepository',

        'git': 'kallithea.lib.vcs.backends.git.GitRepository',

    }

    settings.GIT_EXECUTABLE_PATH = config.get('git_path', 'git')

    settings.GIT_REV_FILTER = config.get('git_rev_filter', '--all').strip()

    settings.DEFAULT_ENCODINGS = aslist(config.get('default_encoding',

                                                        'utf-8'), sep=',')

def set_indexer_config(config):

    """

    Update Whoosh index mapping

    :param config: kallithea.CONFIG

    """

    log.debug('adding extra into INDEX_EXTENSIONS')

    kallithea.config.conf.INDEX_EXTENSIONS.extend(re.split(r'\s+', config.get('index.extensions', '')))

    log.debug('adding extra into INDEX_FILENAMES')

    kallithea.config.conf.INDEX_FILENAMES.extend(re.split(r'\s+', config.get('index.filenames', '')))

def map_groups(path):

    """

    Given a full path to a repository, create all nested groups that this

    repo is inside. This function creates parent-child relationships between

    groups and creates default perms for all new groups.

    :param paths: full path to repository

    """

    from kallithea.model.repo_group import RepoGroupModel

    sa = meta.Session()

    groups = path.split(db.URL_SEP)

    parent = None

    group = None

    # last element is repo in nested groups structure

    groups = groups[:-1]

    rgm = RepoGroupModel()

    owner = User.get_first_admin()

    for lvl, group_name in enumerate(groups):

        group_name = '/'.join(groups[:lvl] + [group_name])

        group = RepoGroup.get_by_group_name(group_name)

        desc = '%s group' % group_name

        # skip folders that are now removed repos

        if REMOVED_REPO_PAT.match(group_name):

            break

        if group is None:

            log.debug('creating group level: %s group_name: %s',

                      lvl, group_name)

            group = RepoGroup(group_name, parent)

            group.group_description = desc

            group.owner = owner

            sa.add(group)

            rgm._create_default_perms(group)

            sa.flush()

        parent = group

    return group

def repo2db_mapper(initial_repo_dict, remove_obsolete=False,

                   install_git_hooks=False, user=None, overwrite_git_hooks=False):

    """

    maps all repos given in initial_repo_dict, non existing repositories

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

    that are not in initial_repo_dict and removes them.

    :param initial_repo_dict: mapping with repositories found by scanning methods

    :param remove_obsolete: check for obsolete entries in database

    :param install_git_hooks: if this is True, also check and install git hook

        for a repo if missing

    :param overwrite_git_hooks: if this is True, overwrite any existing git hooks

        that may be encountered (even if user-deployed)

    """

    from kallithea.model.repo import RepoModel

    from kallithea.model.scm import ScmModel

    sa = meta.Session()

    repo_model = RepoModel()

    if user is None:

        user = User.get_first_admin()

    added = []

    # creation defaults

    defs = Setting.get_default_repo_settings(strip_prefix=True)

    enable_statistics = defs.get('repo_enable_statistics')

    enable_downloads = defs.get('repo_enable_downloads')

    private = defs.get('repo_private')

        group = map_groups(name)

        db_repo = repo_model.get_by_repo_name(name)

        # found repo that is on filesystem not in Kallithea database

        if not db_repo:

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

            added.append(name)

            desc = (repo.description

                    if repo.description != 'unknown'

                    else '%s repository' % name)

            new_repo = repo_model._create_repo(

                repo_name=name,

                repo_type=repo.alias,

                description=desc,

                repo_group=getattr(group, 'group_id', None),

                owner=user,

                enable_downloads=enable_downloads,

                enable_statistics=enable_statistics,

                private=private,

                state=Repository.STATE_CREATED

            )

            sa.commit()

            # we added that repo just now, and make sure it has githook

            # installed, and updated server info

            if new_repo.repo_type == 'git':

                git_repo = new_repo.scm_instance

                ScmModel().install_git_hooks(git_repo)

                # update repository server-info

                log.debug('Running update server info')

                git_repo._update_server_info()

            new_repo.update_changeset_cache()

        elif install_git_hooks:

            if db_repo.repo_type == 'git':

                ScmModel().install_git_hooks(db_repo.scm_instance, force=overwrite_git_hooks)

    removed = []

    # 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_dict:

            if remove_obsolete:

                log.debug("Removing non-existing repository found in db `%s`",

                          repo.repo_name)

                try:

                    RepoModel().delete(repo, forks='detach', fs_remove=False)

                    sa.commit()

                except Exception:

                    #don't hold further removals on error

                    log.error(traceback.format_exc())

                    sa.rollback()

            removed.append(repo.repo_name)

    return added, removed

def load_rcextensions(root_path):

    path = os.path.join(root_path, 'rcextensions', '__init__.py')

    if os.path.isfile(path):

        rcext = create_module('rc', path)

        EXT = kallithea.EXTENSIONS = rcext

        log.debug('Found rcextensions now loading %s...', rcext)

        # Additional mappings that are not present in the pygments lexers

        kallithea.config.conf.LANGUAGES_EXTENSIONS_MAP.update(getattr(EXT, 'EXTRA_MAPPINGS', {}))

        # OVERRIDE OUR EXTENSIONS FROM RC-EXTENSIONS (if present)

        if getattr(EXT, 'INDEX_EXTENSIONS', []):

            log.debug('settings custom INDEX_EXTENSIONS')

            kallithea.config.conf.INDEX_EXTENSIONS = getattr(EXT, 'INDEX_EXTENSIONS', [])

        # ADDITIONAL MAPPINGS

        log.debug('adding extra into INDEX_EXTENSIONS')

        kallithea.config.conf.INDEX_EXTENSIONS.extend(getattr(EXT, 'EXTRA_INDEX_EXTENSIONS', []))

        # auto check if the module is not missing any data, set to default if is

        # this will help autoupdate new feature of rcext module

        #from kallithea.config import rcextensions

        #for k in dir(rcextensions):

        #    if not k.startswith('_') and not hasattr(EXT, k):

        #        setattr(EXT, k, getattr(rcextensions, k))

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

# MISC

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

git_req_ver = StrictVersion('1.7.4')

def check_git_version():

    """

    Checks what version of git is installed on the system, and raise a system exit

    if it's too old for Kallithea to work properly.

    """

    if 'git' not in kallithea.BACKENDS:

        return None

    if not settings.GIT_EXECUTABLE_PATH:

        log.warning('No git executable configured - check "git_path" in the ini file.')

        return None

    try:

        stdout, stderr = GitRepository._run_git_command(['--version'])

    except RepositoryError as e:

        # message will already have been logged as error

        log.warning('No working git executable found - check "git_path" in the ini file.')

        return None

    if stderr:

        log.warning('Error/stderr from "%s --version":\n%s', settings.GIT_EXECUTABLE_PATH, safe_str(stderr))

    if not stdout:

        log.warning('No working git executable found - check "git_path" in the ini file.')

        return None

    output = safe_str(stdout).strip()

    m = re.search(r"\d+.\d+.\d+", output)

    if m:

        ver = StrictVersion(m.group(0))

        log.debug('Git executable: "%s", version %s (parsed from: "%s")',

                  settings.GIT_EXECUTABLE_PATH, ver, output)

        if ver < git_req_ver:

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

                      'for the system to function properly. '

                      'Please upgrade to version %s or later. '

                      'If you strictly need Mercurial repositories, you can '

                      'clear the "git_path" setting in the ini file.',

                      settings.GIT_EXECUTABLE_PATH, ver, git_req_ver)

            log.error("Terminating ...")

            sys.exit(1)

    else:

        ver = StrictVersion('0.0.0')

        log.warning('Error finding version number in "%s --version" stdout:\n%s',

                    settings.GIT_EXECUTABLE_PATH, output)

    return ver