h.flash(_('Error occurred during commit'), category='error')

            return redirect(url('changeset_home',

                                repo_name=c.repo_name, revision='tip'))

        return render('files/files_edit.html')

    @HasRepoPermissionAnyDecorator('repository.write', 'repository.admin')

    def add(self, repo_name, revision, f_path):

        r_post = request.POST

        c.cs = self.__get_cs_or_redirect(revision, repo_name,

                                         redirect_after=False)

        if c.cs is None:

            c.cs = EmptyChangeset(alias=c.rhodecode_repo.alias)

        c.f_path = f_path

        if r_post:

            unix_mode = 0

            content = convert_line_endings(r_post.get('content'), unix_mode)

            message = r_post.get('message') or (_('Added %s via RhodeCode')

                                                % (f_path))

            location = r_post.get('location')

            filename = r_post.get('filename')

            file_obj = r_post.get('upload_file', None)

            if file_obj is not None and hasattr(file_obj, 'filename'):

                filename = file_obj.filename

                content = file_obj.file

            node_path = os.path.join(location, filename)

            author = self.rhodecode_user.full_contact

            if not content:

                h.flash(_('No content'), category='warning')

                return redirect(url('changeset_home', repo_name=c.repo_name,

                                    revision='tip'))

            if not filename:

                h.flash(_('No filename'), category='warning')

                return redirect(url('changeset_home', repo_name=c.repo_name,

                                    revision='tip'))

            try:

                self.scm_model.create_node(repo=c.rhodecode_repo,

                                           repo_name=repo_name, cs=c.cs,

                                           user=self.rhodecode_user,

                                           author=author, message=message,

                                           content=content, f_path=node_path)

                h.flash(_('Successfully committed to %s' % node_path),

                        category='success')

            except NodeAlreadyExistsError, e:

                h.flash(_(e), category='error')

            except Exception:

                log.error(traceback.format_exc())

                h.flash(_('Error occurred during commit'), category='error')

            return redirect(url('changeset_home',

                                repo_name=c.repo_name, revision='tip'))

        return render('files/files_add.html')

    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',

                                   'repository.admin')

    def archivefile(self, repo_name, fname):

        fileformat = None

        revision = None

        ext = None

        subrepos = request.GET.get('subrepos') == 'true'

        for a_type, ext_data in settings.ARCHIVE_SPECS.items():

            archive_spec = fname.split(ext_data[1])

            if len(archive_spec) == 2 and archive_spec[1] == '':

                fileformat = a_type or ext_data[1]

                revision = archive_spec[0]

                ext = ext_data[1]

        try:

            dbrepo = RepoModel().get_by_repo_name(repo_name)

            if dbrepo.enable_downloads is False:

                return _('downloads disabled')

            if c.rhodecode_repo.alias == 'hg':

                # patch and reset hooks section of UI config to not run any

                # hooks on fetching archives with subrepos

                for k, v in c.rhodecode_repo._repo.ui.configitems('hooks'):

                    c.rhodecode_repo._repo.ui.setconfig('hooks', k, None)

            cs = c.rhodecode_repo.get_changeset(revision)

            content_type = settings.ARCHIVE_SPECS[fileformat][0]

        except ChangesetDoesNotExistError:

            return _('Unknown revision %s') % revision

        except EmptyRepositoryError:

            return _('Empty repository')

        except (ImproperArchiveTypeError, KeyError):

            return _('Unknown archive type')

        cs.fill_archive(stream=archive, kind=fileformat, subrepos=subrepos)

        response.content_type = content_type

        response.content_disposition = 'attachment; filename=%s-%s%s' \

            % (repo_name, revision[:12], ext)

        response.content_length = str(os.path.getsize(archive.name))

        def get_chunked_archive(tmpfile):

            while True:

                data = tmpfile.read(16 * 1024)

                if not data:

                    tmpfile.close()

                    break

                yield data

    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',

                                   'repository.admin')

    def diff(self, repo_name, f_path):

        ignore_whitespace = request.GET.get('ignorews') == '1'

        line_context = request.GET.get('context', 3)

        diff1 = request.GET.get('diff1', '')

        diff2 = request.GET.get('diff2', '')

        c.action = request.GET.get('diff')

        c.no_changes = diff1 == diff2

        c.f_path = f_path

        c.big_diff = False

        c.anchor_url = anchor_url

        c.ignorews_url = _ignorews_url

        c.context_url = _context_url

        c.changes = OrderedDict()

        c.changes[diff2] = []

        try:

            if diff1 not in ['', None, 'None', '0' * 12, '0' * 40]:

                c.changeset_1 = c.rhodecode_repo.get_changeset(diff1)

                node1 = c.changeset_1.get_node(f_path)

            else:

                c.changeset_1 = EmptyChangeset(repo=c.rhodecode_repo)

                node1 = FileNode('.', '', changeset=c.changeset_1)

            if diff2 not in ['', None, 'None', '0' * 12, '0' * 40]:

                c.changeset_2 = c.rhodecode_repo.get_changeset(diff2)

                node2 = c.changeset_2.get_node(f_path)

            else:

                c.changeset_2 = EmptyChangeset(repo=c.rhodecode_repo)

                node2 = FileNode('.', '', changeset=c.changeset_2)

        except RepositoryError:

            return redirect(url('files_home', repo_name=c.repo_name,

                                f_path=f_path))

        if c.action == 'download':

            _diff = diffs.get_gitdiff(node1, node2,

                                      ignore_whitespace=ignore_whitespace,

                                      context=line_context)

            diff = diffs.DiffProcessor(_diff, format='gitdiff')

            diff_name = '%s_vs_%s.diff' % (diff1, diff2)

            response.content_type = 'text/plain'

            response.content_disposition = (

                'attachment; filename=%s' % diff_name

            )

            return diff.raw_diff()

        elif c.action == 'raw':

            _diff = diffs.get_gitdiff(node1, node2,

                                      ignore_whitespace=ignore_whitespace,

                                      context=line_context)

            diff = diffs.DiffProcessor(_diff, format='gitdiff')

            response.content_type = 'text/plain'

            return diff.raw_diff()

        else:

            fid = h.FID(diff2, node2.path)

            line_context_lcl = get_line_ctx(fid, request.GET)

            ign_whitespace_lcl = get_ignore_ws(fid, request.GET)

            lim = request.GET.get('fulldiff') or self.cut_off_limit

            _, cs1, cs2, diff, st = diffs.wrapped_diff(filenode_old=node1,

                                         filenode_new=node2,

                                         cut_off_limit=lim,

                                         ignore_whitespace=ign_whitespace_lcl,

                                         line_context=line_context_lcl,

                                         enable_comments=False)

            c.changes = [('', node2, diff, cs1, cs2, st,)]

        return render('files/file_diff.html')

    def _get_node_history(self, cs, f_path):

        changesets = cs.get_file_history(f_path)

        hist_l = []

        changesets_group = ([], _("Changesets"))

        branches_group = ([], _("Branches"))

        tags_group = ([], _("Tags"))

        _hg = cs.repository.alias == 'hg'

        for chs in changesets:

            _branch = '(%s)' % chs.branch if _hg else ''

            n_desc = 'r%s:%s %s' % (chs.revision, chs.short_id, _branch)

            changesets_group[0].append((chs.raw_id, n_desc,))

        hist_l.append(changesets_group)

        for name, chs in c.rhodecode_repo.branches.items():

            branches_group[0].append((chs, name),)

        hist_l.append(branches_group)

        for name, chs in c.rhodecode_repo.tags.items():

            tags_group[0].append((chs, name),)

        hist_l.append(tags_group)

# -*- coding: utf-8 -*-

"""

    rhodecode.lib.auth

    ~~~~~~~~~~~~~~~~~~

    authentication and permission libraries

    :created_on: Apr 4, 2010

    :author: marcink

    :copyright: (C) 2010-2012 Marcin Kuzminski <marcin@python-works.com>

    :license: GPLv3, see COPYING for more details.

"""

# This program is free software: you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation, either version 3 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import random

import logging

import traceback

import hashlib

from tempfile import _RandomNameSequence

from decorator import decorator

from pylons import config, url, request

from pylons.controllers.util import abort, redirect

from pylons.i18n.translation import _

from rhodecode import __platform__, PLATFORM_WIN, PLATFORM_OTHERS

from rhodecode.model.meta import Session

if __platform__ in PLATFORM_WIN:

    from hashlib import sha256

if __platform__ in PLATFORM_OTHERS:

    import bcrypt

from rhodecode.lib.utils2 import str2bool, safe_unicode

from rhodecode.lib.exceptions import LdapPasswordError, LdapUsernameError

from rhodecode.lib.utils import get_repo_slug, get_repos_group_slug

from rhodecode.lib.auth_ldap import AuthLdap

from rhodecode.model import meta

from rhodecode.model.user import UserModel

from rhodecode.model.db import Permission, RhodeCodeSetting, User

log = logging.getLogger(__name__)

class PasswordGenerator(object):

    """

    This is a simple class for generating password from different sets of

    characters

    usage::

        passwd_gen = PasswordGenerator()

        #print 8-letter password containing only big and small letters

            of alphabet

    """

    ALPHABETS_NUM = r'''1234567890'''

    ALPHABETS_SMALL = r'''qwertyuiopasdfghjklzxcvbnm'''

    ALPHABETS_BIG = r'''QWERTYUIOPASDFGHJKLZXCVBNM'''

    ALPHABETS_SPECIAL = r'''`-=[]\;',./~!@#$%^&*()_+{}|:"<>?'''

    ALPHABETS_FULL = ALPHABETS_BIG + ALPHABETS_SMALL \

        + ALPHABETS_NUM + ALPHABETS_SPECIAL

    ALPHABETS_ALPHANUM = ALPHABETS_BIG + ALPHABETS_SMALL + ALPHABETS_NUM

    ALPHABETS_BIG_SMALL = ALPHABETS_BIG + ALPHABETS_SMALL

    ALPHABETS_ALPHANUM_BIG = ALPHABETS_BIG + ALPHABETS_NUM

    ALPHABETS_ALPHANUM_SMALL = ALPHABETS_SMALL + ALPHABETS_NUM

    def __init__(self, passwd=''):

        self.passwd = passwd

    def gen_password(self, length, type_=None):

        if type_ is None:

            type_ = self.ALPHABETS_FULL

        self.passwd = ''.join([random.choice(type_) for _ in xrange(length)])

        return self.passwd

class RhodeCodeCrypto(object):

    @classmethod

    def hash_string(cls, str_):

        """

        Cryptographic function used for password hashing based on pybcrypt

        or pycrypto in windows

        :param password: password to hash

        """

        if __platform__ in PLATFORM_WIN:

            return sha256(str_).hexdigest()

        elif __platform__ in PLATFORM_OTHERS:

            return bcrypt.hashpw(str_, bcrypt.gensalt(10))

        else:

            raise Exception('Unknown or unsupported platform %s' \

                            % __platform__)

    @classmethod

    def hash_check(cls, password, hashed):

        """

        Checks matching password with it's hashed value, runs different

        implementation based on platform it runs on

        :param password: password

        :param hashed: password in hashed form

        """

        if __platform__ in PLATFORM_WIN:

            return sha256(password).hexdigest() == hashed

        elif __platform__ in PLATFORM_OTHERS:

            return bcrypt.hashpw(password, hashed) == hashed

        else:

            raise Exception('Unknown or unsupported platform %s' \

                            % __platform__)

def get_crypt_password(password):

    return RhodeCodeCrypto.hash_string(password)

def check_password(password, hashed):

    return RhodeCodeCrypto.hash_check(password, hashed)

def generate_api_key(str_, salt=None):

    """

    Generates API KEY from given string

    :param str_:

    :param salt:

    """

    if salt is None:

        salt = _RandomNameSequence().next()

    return hashlib.sha1(str_ + salt).hexdigest()

def authfunc(environ, username, password):

    """

    Dummy authentication wrapper function used in Mercurial and Git for

    access control.

    :param environ: needed only for using in Basic auth

    """

    return authenticate(username, password)

def authenticate(username, password):

    """

    Authentication function used for access control,

    firstly checks for db authentication then if ldap is enabled for ldap

    authentication, also creates ldap user if not in database

    elif line.endswith('\r'):

        return 1

    else:

        return default

def generate_api_key(username, salt=None):

    """

    Generates unique API key for given username, if salt is not given

    it'll be generated from some random string

    :param username: username as string

    :param salt: salt to hash generate KEY

    :rtype: str

    :returns: sha1 hash from username+salt

    """

    from tempfile import _RandomNameSequence

    import hashlib

    if salt is None:

        salt = _RandomNameSequence().next()

    return hashlib.sha1(username + salt).hexdigest()

def safe_unicode(str_, from_encoding=None):

    """

    safe unicode function. Does few trick to turn str_ into unicode

    In case of UnicodeDecode error we try to return it with encoding detected

    by chardet library if it fails fallback to unicode with errors replaced

    :param str_: string to decode

    :rtype: unicode

    :returns: unicode object

    """

    if isinstance(str_, unicode):

        return str_

    if not from_encoding:

        import rhodecode

        DEFAULT_ENCODING = rhodecode.CONFIG.get('default_encoding','utf8')

        from_encoding = DEFAULT_ENCODING

    try:

        return unicode(str_)

    except UnicodeDecodeError:

        pass

    try:

        return unicode(str_, from_encoding)

    except UnicodeDecodeError:

        pass

    try:

        import chardet

        encoding = chardet.detect(str_)['encoding']

        if encoding is None:

            raise Exception()

        return str_.decode(encoding)

    except (ImportError, UnicodeDecodeError, Exception):

        return unicode(str_, from_encoding, 'replace')

def safe_str(unicode_, to_encoding=None):

    """

    safe str function. Does few trick to turn unicode_ into string

    In case of UnicodeEncodeError we try to return it with encoding detected

    by chardet library if it fails fallback to string with errors replaced

    :param unicode_: unicode to encode

    :rtype: str

    :returns: str object

    """

    # if it's not basestr cast to str

    if not isinstance(unicode_, basestring):

        return str(unicode_)

    if isinstance(unicode_, str):

        return unicode_

    if not to_encoding:

        import rhodecode

        DEFAULT_ENCODING = rhodecode.CONFIG.get('default_encoding','utf8')

        to_encoding = DEFAULT_ENCODING

    try:

        return unicode_.encode(to_encoding)

    except UnicodeEncodeError:

        pass

    try:

        import chardet

        encoding = chardet.detect(unicode_)['encoding']

        if encoding is None:

            raise UnicodeEncodeError()

        return unicode_.encode(encoding)

    except (ImportError, UnicodeEncodeError):

        return unicode_.encode(to_encoding, 'replace')

    return safe_str

def engine_from_config(configuration, prefix='sqlalchemy.', **kwargs):

    """

    Custom engine_from_config functions that makes sure we use NullPool for

    file based sqlite databases. This prevents errors on sqlite. This only

    applies to sqlalchemy versions < 0.7.0

    """

    import sqlalchemy

    from sqlalchemy import engine_from_config as efc

    import logging

    if int(sqlalchemy.__version__.split('.')[1]) < 7:

        # This solution should work for sqlalchemy < 0.7.0, and should use

        # proxy=TimerProxy() for execution time profiling

        from sqlalchemy.pool import NullPool

        url = configuration[prefix + 'url']

        if url.startswith('sqlite'):

            kwargs.update({'poolclass': NullPool})

        return efc(configuration, prefix, **kwargs)

    else:

        import time

        from sqlalchemy import event

        from sqlalchemy.engine import Engine

        log = logging.getLogger('sqlalchemy.engine')

        BLACK, RED, GREEN, YELLOW, BLUE, MAGENTA, CYAN, WHITE = xrange(30, 38)

        engine = efc(configuration, prefix, **kwargs)

        def color_sql(sql):

            COLOR_SEQ = "\033[1;%dm"

            COLOR_SQL = YELLOW

            normal = '\x1b[0m'

            return ''.join([COLOR_SEQ % COLOR_SQL, sql, normal])

        if configuration['debug']:

            #attach events only for debug configuration

            def before_cursor_execute(conn, cursor, statement,

                                    parameters, context, executemany):

                context._query_start_time = time.time()

                log.info(color_sql(">>>>> STARTING QUERY >>>>>"))

            def after_cursor_execute(conn, cursor, statement,

                                    parameters, context, executemany):

                total = time.time() - context._query_start_time

                log.info(color_sql("<<<<< TOTAL TIME: %f <<<<<" % total))

            event.listen(engine, "before_cursor_execute",

                         before_cursor_execute)

            event.listen(engine, "after_cursor_execute",

                         after_cursor_execute)

    return engine

def age(curdate):

    """

    turns a datetime into an age string.

    :param curdate: datetime object

    :rtype: unicode

    :returns: unicode words describing age

    """

    from datetime import datetime

    from webhelpers.date import time_ago_in_words

    _ = lambda s: s

    if not curdate:

        return ''

    agescales = [(_(u"year"), 3600 * 24 * 365),

                 (_(u"month"), 3600 * 24 * 30),

                 (_(u"day"), 3600 * 24),

                 (_(u"hour"), 3600),

                 (_(u"minute"), 60),

                 (_(u"second"), 1), ]

    age = datetime.now() - curdate

    age_seconds = (age.days * agescales[2][1]) + age.seconds

    pos = 1

    def _get_file_nodes(self):

        return chain(*(t[2] for t in self.walk()))

    @LazyProperty

    def parents(self):

        """

        Returns list of parents changesets.

        """

        return [self.repository.get_changeset(parent)

            for parent in self._commit.parents]

    def next(self, branch=None):

        if branch and self.branch != branch:

            raise VCSError('Branch option used on changeset not belonging '

                           'to that branch')

        def _next(changeset, branch):

            try:

                next_ = changeset.revision + 1

                next_rev = changeset.repository.revisions[next_]

            except IndexError:

                raise ChangesetDoesNotExistError

            cs = changeset.repository.get_changeset(next_rev)

            if branch and branch != cs.branch:

                return _next(cs, branch)

            return cs

        return _next(self, branch)

    def prev(self, branch=None):

        if branch and self.branch != branch:

            raise VCSError('Branch option used on changeset not belonging '

                           'to that branch')

        def _prev(changeset, branch):

            try:

                prev_ = changeset.revision - 1

                if prev_ < 0:

                    raise IndexError

                prev_rev = changeset.repository.revisions[prev_]

            except IndexError:

                raise ChangesetDoesNotExistError

            cs = changeset.repository.get_changeset(prev_rev)

            if branch and branch != cs.branch:

                return _prev(cs, branch)

            return cs

        return _prev(self, branch)

    def get_file_mode(self, path):

        """

        Returns stat mode of the file at the given ``path``.

        """

        # ensure path is traversed

        self._get_id_for_path(path)

        return self._stat_modes[path]

    def get_file_content(self, path):

        """

        Returns content of the file at given ``path``.

        """

        id = self._get_id_for_path(path)

        blob = self.repository._repo[id]

        return blob.as_pretty_string()

    def get_file_size(self, path):

        """

        Returns size of the file at given ``path``.

        """

        id = self._get_id_for_path(path)

        blob = self.repository._repo[id]

        return blob.raw_length()

    def get_file_changeset(self, path):

        """

        Returns last commit of the file at the given ``path``.

        """

        node = self.get_node(path)

        return node.history[0]

    def get_file_history(self, path):

        """

        Returns history of file as reversed list of ``Changeset`` objects for

        which file at given ``path`` has been modified.

        TODO: This function now uses os underlying 'git' and 'grep' commands

        which is generally not good. Should be replaced with algorithm

        iterating commits.

        """

                  self.id, path

               )

        so, se = self.repository.run_git_command(cmd)

        return [self.repository.get_changeset(id) for id in ids]

    def get_file_annotate(self, path):

        """

        Returns a list of three element tuples with lineno,changeset and line

        TODO: This function now uses os underlying 'git' command which is

        generally not good. Should be replaced with algorithm iterating

        commits.

        """

        cmd = 'blame -l --root -r %s -- "%s"' % (self.id, path)

        # -l     ==> outputs long shas (and we need all 40 characters)

        # --root ==> doesn't put '^' character for bounderies

        # -r sha ==> blames for the given revision

        so, se = self.repository.run_git_command(cmd)

        annotate = []

        for i, blame_line in enumerate(so.split('\n')[:-1]):

            ln_no = i + 1

            id, line = re.split(r' \(.+?\) ', blame_line, 1)

            annotate.append((ln_no, self.repository.get_changeset(id), line))

        return annotate

    def fill_archive(self, stream=None, kind='tgz', prefix=None,

                     subrepos=False):

        """

        Fills up given stream.

        :param stream: file like object.

        :param kind: one of following: ``zip``, ``tgz`` or ``tbz2``.

            Default: ``tgz``.

        :param prefix: name of root directory in archive.

            Default is repository name and changeset's raw_id joined with dash

            (``repo-tip.<KIND>``).

        :param subrepos: include subrepos in this archive.

        :raise ImproperArchiveTypeError: If given kind is wrong.

        :raise VcsError: If given stream is None

        """

        allowed_kinds = settings.ARCHIVE_SPECS.keys()

        if kind not in allowed_kinds:

            raise ImproperArchiveTypeError('Archive kind not supported use one'

                'of %s', allowed_kinds)

        if prefix is None:

            prefix = '%s-%s' % (self.repository.name, self.short_id)

        elif prefix.startswith('/'):

            raise VCSError("Prefix cannot start with leading slash")

        elif prefix.strip() == '':

            raise VCSError("Prefix cannot be empty")

        if kind == 'zip':

            frmt = 'zip'

        else:

            frmt = 'tar'

        cmd = 'git archive --format=%s --prefix=%s/ %s' % (frmt, prefix,

            self.raw_id)

        if kind == 'tgz':

            cmd += ' | gzip -9'

        elif kind == 'tbz2':

            cmd += ' | bzip2 -9'

        if stream is None:

            raise VCSError('You need to pass in a valid stream for filling'

                           ' with archival data')

        popen = Popen(cmd, stdout=PIPE, stderr=PIPE, shell=True,

            cwd=self.repository.path)

        buffer_size = 1024 * 8

        chunk = popen.stdout.read(buffer_size)

        while chunk:

            stream.write(chunk)

            chunk = popen.stdout.read(buffer_size)

        # Make sure all descriptors would be read

        popen.communicate()

    def get_nodes(self, path):

        if self._get_kind(path) != NodeKind.DIR:

            raise ChangesetError("Directory does not exist for revision %r at "

                " %r" % (self.revision, path))

        path = self._fix_path(path)

        id = self._get_id_for_path(path)

        tree = self.repository._repo[id]

        dirnodes = []

        filenodes = []

        als = self.repository.alias

        for name, stat, id in tree.iteritems():

            if objects.S_ISGITLINK(stat):

                dirnodes.append(SubModuleNode(name, url=None, changeset=id,

                                              alias=als))

                continue

            obj = self.repository._repo.get_object(id)

            if path != '':

                obj_path = '/'.join((path, name))

            else:

"""

This module provides some useful tools for ``vcs`` like annotate/diff html

output. It also includes some internal helpers.

"""

import sys

import time

import datetime

def makedate():

    lt = time.localtime()

    if lt[8] == 1 and time.daylight:

        tz = time.altzone

    else:

        tz = time.timezone

    return time.mktime(lt), tz

def date_fromtimestamp(unixts, tzoffset=0):

    """

    Makes a local datetime object out of unix timestamp

    :param unixts:

    :param tzoffset:

    """

    return datetime.datetime.fromtimestamp(float(unixts))

def safe_unicode(str_, from_encoding=None):

    """

    safe unicode function. Does few trick to turn str_ into unicode

    In case of UnicodeDecode error we try to return it with encoding detected

    by chardet library if it fails fallback to unicode with errors replaced

    :param str_: string to decode

    :rtype: unicode

    :returns: unicode object

    """

    if isinstance(str_, unicode):

        return str_

    if not from_encoding:

        import rhodecode

        DEFAULT_ENCODING = rhodecode.CONFIG.get('default_encoding', 'utf8')

        from_encoding = DEFAULT_ENCODING

    try:

        return unicode(str_)

    except UnicodeDecodeError:

        pass

    try:

        return unicode(str_, from_encoding)

    except UnicodeDecodeError:

        pass

    try:

        import chardet

        encoding = chardet.detect(str_)['encoding']

        if encoding is None:

            raise Exception()

        return str_.decode(encoding)

    except (ImportError, UnicodeDecodeError, Exception):

        return unicode(str_, from_encoding, 'replace')

def safe_str(unicode_, to_encoding=None):

    """

    safe str function. Does few trick to turn unicode_ into string

    In case of UnicodeEncodeError we try to return it with encoding detected

    by chardet library if it fails fallback to string with errors replaced

    :param unicode_: unicode to encode

    :rtype: str

    :returns: str object

    """

    if isinstance(unicode_, str):

        return unicode_

    if not to_encoding:

        import rhodecode

        DEFAULT_ENCODING = rhodecode.CONFIG.get('default_encoding', 'utf8')

        to_encoding = DEFAULT_ENCODING

    try:

        return unicode_.encode(to_encoding)

    except UnicodeEncodeError:

        pass