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

"""

    vcs.backends.git.repository

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

    Git repository implementation.

    :created_on: Apr 8, 2010

    :copyright: (c) 2010-2011 by Marcin Kuzminski, Lukasz Balcerzak.

"""

import errno

import logging

import os

import re

import time

import urllib.error

import urllib.parse

import urllib.request

from collections import OrderedDict

import mercurial.util  # import url as hg_url

from dulwich.client import SubprocessGitClient

from dulwich.config import ConfigFile

from dulwich.objects import Tag

from dulwich.repo import NotGitRepository, Repo

from dulwich.server import update_server_info

from kallithea.lib.vcs import subprocessio

from kallithea.lib.vcs.backends.base import BaseRepository, CollectionGenerator

from kallithea.lib.vcs.conf import settings

from kallithea.lib.vcs.exceptions import (BranchDoesNotExistError, ChangesetDoesNotExistError, EmptyRepositoryError, RepositoryError, TagAlreadyExistError,

                                          TagDoesNotExistError)

from kallithea.lib.vcs.utils import ascii_bytes, ascii_str, date_fromtimestamp, makedate, safe_bytes, safe_str

from kallithea.lib.vcs.utils.helpers import get_urllib_request_handlers

from kallithea.lib.vcs.utils.lazy import LazyProperty

from kallithea.lib.vcs.utils.paths import abspath, get_user_home

from . import changeset, inmemory, workdir

SHA_PATTERN = re.compile(r'^([0-9a-fA-F]{12}|[0-9a-fA-F]{40})$')

log = logging.getLogger(__name__)

class GitRepository(BaseRepository):

    """

    Git repository backend.

    """

    DEFAULT_BRANCH_NAME = 'master'

    scm = 'git'

    def __init__(self, repo_path, create=False, src_url=None,

                 update_after_clone=False, bare=False, baseui=None):

        baseui  # unused

        self.path = abspath(repo_path)

        self.repo = self._get_repo(create, src_url, update_after_clone, bare)

        self.bare = self.repo.bare

    @property

    def _config_files(self):

        return [

            self.bare and abspath(self.path, 'config')

                      or abspath(self.path, '.git', 'config'),

             abspath(get_user_home(), '.gitconfig'),

         ]

    @property

    def _repo(self):

        return self.repo

    @property

    def head(self):

        try:

            return self._repo.head()

        except KeyError:

            return None

    @property

    def _empty(self):

        """

        Checks if repository is empty ie. without any changesets

        """

        try:

            self.revisions[0]

        except (KeyError, IndexError):

            return True

        return False

    @LazyProperty

    def revisions(self):

        """

        Returns list of revisions' ids, in ascending order.  Being lazy

        attribute allows external tools to inject shas from cache.

        """

        return self._get_all_revisions()

    @classmethod

    def _run_git_command(cls, cmd, cwd=None):

        """

        Runs given ``cmd`` as git command and returns output bytes in a tuple

        (stdout, stderr) ... or raise RepositoryError.

        :param cmd: git command to be executed

        :param cwd: passed directly to subprocess

        """

        # need to clean fix GIT_DIR !

        gitenv = dict(os.environ)

        gitenv.pop('GIT_DIR', None)

        gitenv['GIT_CONFIG_NOGLOBAL'] = '1'

        assert isinstance(cmd, list), cmd

        cmd = [settings.GIT_EXECUTABLE_PATH, '-c', 'core.quotepath=false'] + cmd

        try:

            p = subprocessio.SubprocessIOChunker(cmd, cwd=cwd, env=gitenv, shell=False)

        except (EnvironmentError, OSError) as err:

            # output from the failing process is in str(EnvironmentError)

            msg = ("Couldn't run git command %s.\n"

                   "Subprocess failed with '%s': %s\n" %

                   (cmd, type(err).__name__, err)

            ).strip()

            log.error(msg)

            raise RepositoryError(msg)

        try:

            stdout = b''.join(p.output)

            stderr = b''.join(p.error)

        finally:

            p.close()

        # TODO: introduce option to make commands fail if they have any stderr output?

        if stderr:

            log.debug('stderr from %s:\n%s', cmd, stderr)

        else:

            log.debug('stderr from %s: None', cmd)

        return stdout, stderr

    def run_git_command(self, cmd):

        """

        Runs given ``cmd`` as git command with cwd set to current repo.

        Returns stdout as unicode str ... or raise RepositoryError.

        """

        cwd = None

        if os.path.isdir(self.path):

            cwd = self.path

        stdout, _stderr = self._run_git_command(cmd, cwd=cwd)

        return safe_str(stdout)

    @staticmethod

    def _check_url(url):

        r"""

        Raise URLError if url doesn't seem like a valid safe Git URL. We

        only allow http, https, git, and ssh URLs.

        For http and https URLs, make a connection and probe to see if it is valid.

        >>> GitRepository._check_url('git://example.com/my%20fine repo')

        >>> GitRepository._check_url('http://example.com:65537/repo')

        Traceback (most recent call last):

        ...

        urllib.error.URLError: <urlopen error Error parsing URL: 'http://example.com:65537/repo'>

        >>> GitRepository._check_url('foo')

        Traceback (most recent call last):

        ...

        urllib.error.URLError: <urlopen error Unsupported protocol in URL 'foo'>

        >>> GitRepository._check_url('file:///repo')

        Traceback (most recent call last):

        ...

        urllib.error.URLError: <urlopen error Unsupported protocol in URL 'file:///repo'>

        >>> GitRepository._check_url('git+http://example.com/repo')

        Traceback (most recent call last):

        ...

        urllib.error.URLError: <urlopen error Unsupported protocol in URL 'git+http://example.com/repo'>

        >>> GitRepository._check_url('git://example.com/%09')

        Traceback (most recent call last):

        ...

        urllib.error.URLError: <urlopen error Invalid escape character in path: '%'>

        >>> GitRepository._check_url('git://example.com/%x00')

        Traceback (most recent call last):

        ...

        urllib.error.URLError: <urlopen error Invalid escape character in path: '%'>

        >>> GitRepository._check_url(r'git://example.com/\u0009')

        Traceback (most recent call last):

        ...

        urllib.error.URLError: <urlopen error Invalid escape character in path: '\'>

        >>> GitRepository._check_url(r'git://example.com/\t')

        Traceback (most recent call last):

        ...

        urllib.error.URLError: <urlopen error Invalid escape character in path: '\'>

        >>> GitRepository._check_url('git://example.com/\t')

        Traceback (most recent call last):

        ...

        urllib.error.URLError: <urlopen error Invalid whitespace character in path: '\t'>

        """

        try:

            parsed_url = urllib.parse.urlparse(url)

            parsed_url.port  # trigger netloc parsing which might raise ValueError

        except ValueError:

            raise urllib.error.URLError("Error parsing URL: %r" % url)

        # check first if it's not an local url

        if os.path.isabs(url) and os.path.isdir(url):

            return

        if parsed_url.scheme == 'git':

            # Mitigate problems elsewhere with incorrect handling of encoded paths.

            # Don't trust urllib.parse.unquote but be prepared for more flexible implementations elsewhere.

            # Space is the only allowed whitespace character - directly or % encoded. No other % or \ is allowed.

            for c in parsed_url.path.replace('%20', ' '):

                if c in '%\\':

                    raise urllib.error.URLError("Invalid escape character in path: '%s'" % c)

                if c.isspace() and c != ' ':

                    raise urllib.error.URLError("Invalid whitespace character in path: %r" % c)

            return

        if parsed_url.scheme not in ['http', 'https']:

            raise urllib.error.URLError("Unsupported protocol in URL %r" % url)

        url_obj = mercurial.util.url(safe_bytes(url))

        test_uri, handlers = get_urllib_request_handlers(url_obj)

        if not test_uri.endswith(b'info/refs'):

            test_uri = test_uri.rstrip(b'/') + b'/info/refs'

        url_obj.passwd = b'*****'

        cleaned_uri = str(url_obj)

        o = urllib.request.build_opener(*handlers)

        o.addheaders = [('User-Agent', 'git/1.7.8.0')]  # fake some git

        req = urllib.request.Request(

            "%s?%s" % (

                safe_str(test_uri),

                urllib.parse.urlencode({"service": 'git-upload-pack'})

            ))

        try:

            resp = o.open(req)

            if resp.code != 200:

                raise Exception('Return Code is not 200')

        except Exception as e:

            # means it cannot be cloned

            raise urllib.error.URLError("[%s] org_exc: %s" % (cleaned_uri, e))

        # now detect if it's proper git repo

        gitdata = resp.read()

        if b'service=git-upload-pack' not in gitdata:

            raise urllib.error.URLError(

                "url [%s] does not look like an git" % cleaned_uri)

    def _get_repo(self, create, src_url=None, update_after_clone=False,

                  bare=False):

        if create and os.path.exists(self.path):

            raise RepositoryError("Location already exist")

        if src_url and not create:

            raise RepositoryError("Create should be set to True if src_url is "

                                  "given (clone operation creates repository)")

        try:

            if create and src_url:

                GitRepository._check_url(src_url)

                self.clone(src_url, update_after_clone, bare)

                return Repo(self.path)

            elif create:

                os.makedirs(self.path)

                if bare:

                    return Repo.init_bare(self.path)

                else:

                    return Repo.init(self.path)

            else:

                return Repo(self.path)

        except (NotGitRepository, OSError) as err:

            raise RepositoryError(err)

    def _get_all_revisions(self):

        # we must check if this repo is not empty, since later command

        # fails if it is. And it's cheaper to ask than throw the subprocess

        # errors

        try:

            self._repo.head()

        except KeyError:

            return []

        rev_filter = settings.GIT_REV_FILTER

        cmd = ['rev-list', rev_filter, '--reverse', '--date-order']

        try:

            so = self.run_git_command(cmd)

        except RepositoryError:

            # Can be raised for empty repositories

            return []

        return so.splitlines()

    def _get_all_revisions2(self):

        # alternate implementation using dulwich

        includes = [ascii_str(sha) for key, (sha, type_) in self._parsed_refs.items()

                    if type_ != b'T']

        return [c.commit.id for c in self._repo.get_walker(include=includes)]

    def _get_revision(self, revision):

        """

        Given any revision identifier, returns a 40 char string with revision hash.

        """

        if self._empty:

            raise EmptyRepositoryError("There are no changesets yet")

        if revision in (None, '', 'tip', 'HEAD', 'head', -1):

            revision = -1

        if isinstance(revision, int):

            try:

                return self.revisions[revision]

            except IndexError:

                msg = "Revision %r does not exist for %s" % (revision, self.name)

                raise ChangesetDoesNotExistError(msg)

        if isinstance(revision, str):

            if revision.isdigit() and (len(revision) < 12 or len(revision) == revision.count('0')):

                try:

                    return self.revisions[int(revision)]

                except IndexError:

                    msg = "Revision %r does not exist for %s" % (revision, self)

                    raise ChangesetDoesNotExistError(msg)

            # get by branch/tag name

            _ref_revision = self._parsed_refs.get(safe_bytes(revision))

            if _ref_revision:  # and _ref_revision[1] in [b'H', b'RH', b'T']:

                return ascii_str(_ref_revision[0])

            if revision in self.revisions:

                return revision

            # maybe it's a tag ? we don't have them in self.revisions

            if revision in self.tags.values():

                return revision

            if SHA_PATTERN.match(revision):

                msg = "Revision %r does not exist for %s" % (revision, self.name)

                raise ChangesetDoesNotExistError(msg)

        raise ChangesetDoesNotExistError("Given revision %r not recognized" % revision)

    def get_ref_revision(self, ref_type, ref_name):

        """

        Returns ``GitChangeset`` object representing repository's

        changeset at the given ``revision``.

        """

        return self._get_revision(ref_name)

    def _get_archives(self, archive_name='tip'):

        for i in [('zip', '.zip'), ('gz', '.tar.gz'), ('bz2', '.tar.bz2')]:

            yield {"type": i[0], "extension": i[1], "node": archive_name}

    def _get_url(self, url):

        """

        Returns normalized url. If schema is not given, would fall to

        filesystem (``file:///``) schema.

        """

        if url != 'default' and '://' not in url:

            url = ':///'.join(('file', url))

        return url

    @LazyProperty

    def name(self):

        return os.path.basename(self.path)

    @LazyProperty

    def last_change(self):

        """

        Returns last change made on this repository as datetime object

        """

        return date_fromtimestamp(self._get_mtime(), makedate()[1])

    def _get_mtime(self):

        try:

            return time.mktime(self.get_changeset().date.timetuple())

        except RepositoryError:

            idx_loc = '' if self.bare else '.git'

            # fallback to filesystem

            in_path = os.path.join(self.path, idx_loc, "index")

            he_path = os.path.join(self.path, idx_loc, "HEAD")

            if os.path.exists(in_path):

                return os.stat(in_path).st_mtime

            else:

                return os.stat(he_path).st_mtime

    @LazyProperty

    def description(self):

        return safe_str(self._repo.get_description() or b'unknown')

    @property

    def branches(self):

        if not self.revisions:

            return {}

        _branches = [(safe_str(key), ascii_str(sha))

                     for key, (sha, type_) in self._parsed_refs.items() if type_ == b'H']

        return OrderedDict(sorted(_branches, key=(lambda ctx: ctx[0]), reverse=False))

    @LazyProperty

    def closed_branches(self):

        return {}

    @LazyProperty

    def tags(self):

        return self._get_tags()

    def _get_tags(self):

        if not self.revisions:

            return {}

        _tags = [(safe_str(key), ascii_str(sha))

                 for key, (sha, type_) in self._parsed_refs.items() if type_ == b'T']

        return OrderedDict(sorted(_tags, key=(lambda ctx: ctx[0]), reverse=True))

    def tag(self, name, user, revision=None, message=None, date=None,

            **kwargs):

        """

        Creates and returns a tag for the given ``revision``.

        :param name: name for new tag

        :param user: full username, i.e.: "Joe Doe <joe.doe@example.com>"

        :param revision: changeset id for which new tag would be created

        :param message: message of the tag's commit

        :param date: date of tag's commit

        :raises TagAlreadyExistError: if tag with same name already exists

        """

        if name in self.tags:

            raise TagAlreadyExistError("Tag %s already exists" % name)

        changeset = self.get_changeset(revision)

        message = message or "Added tag %s for commit %s" % (name,

            changeset.raw_id)

        self._repo.refs[b"refs/tags/%s" % safe_bytes(name)] = changeset._commit.id

        self._parsed_refs = self._get_parsed_refs()

        self.tags = self._get_tags()

        return changeset

    def remove_tag(self, name, user, message=None, date=None):

        """

        Removes tag with the given ``name``.

        :param name: name of the tag to be removed

        :param user: full username, i.e.: "Joe Doe <joe.doe@example.com>"

        :param message: message of the tag's removal commit

        :param date: date of tag's removal commit

        :raises TagDoesNotExistError: if tag with given name does not exists

        """

        if name not in self.tags:

            raise TagDoesNotExistError("Tag %s does not exist" % name)

        # self._repo.refs is a DiskRefsContainer, and .path gives the full absolute path of '.git'

        tagpath = os.path.join(safe_str(self._repo.refs.path), 'refs', 'tags', name)

        try:

            os.remove(tagpath)

            self._parsed_refs = self._get_parsed_refs()

            self.tags = self._get_tags()

        except OSError as e:

            raise RepositoryError(e.strerror)

    @LazyProperty

    def bookmarks(self):

        """

        Gets bookmarks for this repository

        """

        return {}

    @LazyProperty

    def _parsed_refs(self):

        return self._get_parsed_refs()

    def _get_parsed_refs(self):

        """Return refs as a dict, like:

        { b'v0.2.0': [b'599ba911aa24d2981225f3966eb659dfae9e9f30', b'T'] }

        """

        _repo = self._repo

        refs = _repo.get_refs()

        keys = [(b'refs/heads/', b'H'),

                (b'refs/remotes/origin/', b'RH'),

                (b'refs/tags/', b'T')]

        _refs = {}

        for ref, sha in refs.items():

            for k, type_ in keys:

                if ref.startswith(k):

                    _key = ref[len(k):]

                    if type_ == b'T':

                        obj = _repo.get_object(sha)

                        if isinstance(obj, Tag):

                            sha = _repo.get_object(sha).object[1]

                    _refs[_key] = [sha, type_]

                    break

        return _refs

    def _heads(self, reverse=False):

        refs = self._repo.get_refs()

        heads = {}

        for key, val in refs.items():

            for ref_key in [b'refs/heads/', b'refs/remotes/origin/']:

                if key.startswith(ref_key):

                    n = key[len(ref_key):]

                    if n not in [b'HEAD']:

                        heads[n] = val

        return heads if reverse else dict((y, x) for x, y in heads.items())

    def get_changeset(self, revision=None):

        """

        Returns ``GitChangeset`` object representing commit from git repository

        at the given revision or head (most recent commit) if None given.

        """

        if isinstance(revision, changeset.GitChangeset):

            return revision

        return changeset.GitChangeset(repository=self, revision=self._get_revision(revision))

    def get_changesets(self, start=None, end=None, start_date=None,

           end_date=None, branch_name=None, reverse=False, max_revisions=None):

        """

        Returns iterator of ``GitChangeset`` objects from start to end (both

        are inclusive), in ascending date order (unless ``reverse`` is set).

        :param start: changeset ID, as str; first returned changeset

        :param end: changeset ID, as str; last returned changeset

        :param start_date: if specified, changesets with commit date less than

          ``start_date`` would be filtered out from returned set

        :param end_date: if specified, changesets with commit date greater than

          ``end_date`` would be filtered out from returned set

        :param branch_name: if specified, changesets not reachable from given

          branch would be filtered out from returned set

        :param reverse: if ``True``, returned generator would be reversed

          (meaning that returned changesets would have descending date order)

        :raise BranchDoesNotExistError: If given ``branch_name`` does not

            exist.

        :raise ChangesetDoesNotExistError: If changeset for given ``start`` or

          ``end`` could not be found.

        """

        if branch_name and branch_name not in self.branches:

            raise BranchDoesNotExistError("Branch '%s' not found"

                                          % branch_name)

        # actually we should check now if it's not an empty repo to not spaw

        # subprocess commands

        if self._empty:

            raise EmptyRepositoryError("There are no changesets yet")

        # %H at format means (full) commit hash, initial hashes are retrieved

        # in ascending date order

        cmd = ['log', '--date-order', '--reverse', '--pretty=format:%H']

        if max_revisions:

            cmd += ['--max-count=%s' % max_revisions]

        if start_date:

            cmd += ['--since', start_date.strftime('%m/%d/%y %H:%M:%S')]

        if end_date:

            cmd += ['--until', end_date.strftime('%m/%d/%y %H:%M:%S')]

        if branch_name:

            cmd.append(branch_name)

        else:

            cmd.append(settings.GIT_REV_FILTER)

        revs = self.run_git_command(cmd).splitlines()

        start_pos = 0

        end_pos = len(revs)

        if start:

            _start = self._get_revision(start)

            try:

                start_pos = revs.index(_start)

            except ValueError:

                pass

        if end is not None:

            _end = self._get_revision(end)

            try:

                end_pos = revs.index(_end)

            except ValueError:

                pass

        if None not in [start, end] and start_pos > end_pos:

            raise RepositoryError('start cannot be after end')

        if end_pos is not None:

            end_pos += 1

        revs = revs[start_pos:end_pos]

        if reverse:

            revs.reverse()

        return CollectionGenerator(self, revs)

    def get_diff_changesets(self, org_rev, other_repo, other_rev):

        """

        Returns lists of changesets that can be merged from this repo @org_rev

        to other_repo @other_rev

        ... and the other way

        ... and the ancestors that would be used for merge

        :param org_rev: the revision we want our compare to be made

        :param other_repo: repo object, most likely the fork of org_repo. It has

            all changesets that we need to obtain

        :param other_rev: revision we want out compare to be made on other_repo

        """

        org_changesets = []

        ancestors = None

        if org_rev == other_rev:

            other_changesets = []

        elif self != other_repo:

            gitrepo = Repo(self.path)

            SubprocessGitClient(thin_packs=False).fetch(other_repo.path, gitrepo)

            gitrepo_remote = Repo(other_repo.path)

            SubprocessGitClient(thin_packs=False).fetch(self.path, gitrepo_remote)

            revs = [

                ascii_str(x.commit.id)

                for x in gitrepo_remote.get_walker(include=[ascii_bytes(other_rev)],

                                                   exclude=[ascii_bytes(org_rev)])

            ]

            other_changesets = [other_repo.get_changeset(rev) for rev in reversed(revs)]

            if other_changesets:

                ancestors = [other_changesets[0].parents[0].raw_id]

            else:

                # no changesets from other repo, ancestor is the other_rev

                ancestors = [other_rev]

            gitrepo.close()

            gitrepo_remote.close()

        else:

            so = self.run_git_command(

                ['log', '--reverse', '--pretty=format:%H',

                 '-s', '%s..%s' % (org_rev, other_rev)]

            )

            other_changesets = [self.get_changeset(cs)

                          for cs in re.findall(r'[0-9a-fA-F]{40}', so)]

            so = self.run_git_command(

                ['merge-base', org_rev, other_rev]

            )

            ancestors = [re.findall(r'[0-9a-fA-F]{40}', so)[0]]

        return other_changesets, org_changesets, ancestors

    def get_diff(self, rev1, rev2, path=None, ignore_whitespace=False,

                 context=3):

        """

        Returns (git like) *diff*, as plain bytes text. Shows changes

        introduced by ``rev2`` since ``rev1``.

        :param rev1: Entry point from which diff is shown. Can be

          ``self.EMPTY_CHANGESET`` - in this case, patch showing all

          the changes since empty state of the repository until ``rev2``

        :param rev2: Until which revision changes should be shown.

        :param ignore_whitespace: If set to ``True``, would not show whitespace

          changes. Defaults to ``False``.

        :param context: How many lines before/after changed lines should be

          shown. Defaults to ``3``. Due to limitations in Git, if

          value passed-in is greater than ``2**31-1``

          (``2147483647``), it will be set to ``2147483647``

          instead. If negative value is passed-in, it will be set to

          ``0`` instead.

        """

        # Git internally uses a signed long int for storing context

        # size (number of lines to show before and after the

        # differences). This can result in integer overflow, so we

        # ensure the requested context is smaller by one than the

        # number that would cause the overflow. It is highly unlikely

        # that a single file will contain that many lines, so this

        # kind of change should not cause any realistic consequences.

        overflowed_long_int = 2**31

        if context >= overflowed_long_int:

            context = overflowed_long_int - 1

        # Negative context values make no sense, and will result in

        # errors. Ensure this does not happen.

        if context < 0:

            context = 0

        flags = ['-U%s' % context, '--full-index', '--binary', '-p', '-M', '--abbrev=40']

        if ignore_whitespace:

            flags.append('-w')

        if hasattr(rev1, 'raw_id'):

            rev1 = getattr(rev1, 'raw_id')

        if hasattr(rev2, 'raw_id'):

            rev2 = getattr(rev2, 'raw_id')

        if rev1 == self.EMPTY_CHANGESET:

            rev2 = self.get_changeset(rev2).raw_id

            cmd = ['show'] + flags + [rev2]

        else:

            rev1 = self.get_changeset(rev1).raw_id

            rev2 = self.get_changeset(rev2).raw_id

            cmd = ['diff'] + flags + [rev1, rev2]

        if path:

            cmd += ['--', path]

        stdout, stderr = self._run_git_command(cmd, cwd=self.path)

        # If we used 'show' command, strip first few lines (until actual diff

        # starts)

        if rev1 == self.EMPTY_CHANGESET:

            parts = stdout.split(b'\ndiff ', 1)

            if len(parts) > 1:

                stdout = b'diff ' + parts[1]

        return stdout

    @LazyProperty

    def in_memory_changeset(self):

        """

        Returns ``GitInMemoryChangeset`` object for this repository.

        """

        return inmemory.GitInMemoryChangeset(self)

    def clone(self, url, update_after_clone=True, bare=False):

        """

        Tries to clone changes from external location.

        :param update_after_clone: If set to ``False``, git won't checkout

          working directory

        :param bare: If set to ``True``, repository would be cloned into

          *bare* git repository (no working directory at all).

        """

        url = self._get_url(url)

        cmd = ['clone', '-q']

        if bare:

            cmd.append('--bare')

        elif not update_after_clone:

            cmd.append('--no-checkout')

        cmd += ['--', url, self.path]

        # If error occurs run_git_command raises RepositoryError already

        self.run_git_command(cmd)

    def pull(self, url):

        """

        Tries to pull changes from external location.

        """

        url = self._get_url(url)

        cmd = ['pull', '--ff-only', url]

        # If error occurs run_git_command raises RepositoryError already

        self.run_git_command(cmd)

    def fetch(self, url):

        """

        Tries to pull changes from external location.

        """

        url = self._get_url(url)

        so = self.run_git_command(['ls-remote', '-h', url])

        cmd = ['fetch', url, '--']

        for line in so.splitlines():

            sha, ref = line.split('\t')

            cmd.append('+%s:%s' % (ref, ref))

        self.run_git_command(cmd)

    def _update_server_info(self):

        """

        runs gits update-server-info command in this repo instance

        """

        try:

            update_server_info(self._repo)

        except OSError as e:

            if e.errno not in [errno.ENOENT, errno.EROFS]:

                raise

            # Workaround for dulwich crashing on for example its own dulwich/tests/data/repos/simple_merge.git/info/refs.lock

            log.error('Ignoring %s running update-server-info: %s', type(e).__name__, e)

    @LazyProperty

    def workdir(self):

        """

        Returns ``Workdir`` instance for this repository.

        """

        return workdir.GitWorkdir(self)

    def get_config_value(self, section, name, config_file=None):

        """

        Returns configuration value for a given [``section``] and ``name``.

        :param section: Section we want to retrieve value from

        :param name: Name of configuration we want to retrieve

        :param config_file: A path to file which should be used to retrieve

          configuration from (might also be a list of file paths)

        """

        if config_file is None:

            config_file = []

        elif isinstance(config_file, str):

            config_file = [config_file]

        def gen_configs():

            for path in config_file + self._config_files:

                try:

                    yield ConfigFile.from_path(path)

                except (IOError, OSError, ValueError):

                    continue

        for config in gen_configs():

            try:

                value = config.get(section, name)

            except KeyError:

                continue

            return None if value is None else safe_str(value)

        return None

    def get_user_name(self, config_file=None):

        """

        Returns user's name from global configuration file.

        :param config_file: A path to file which should be used to retrieve

          configuration from (might also be a list of file paths)

        """

        return self.get_config_value('user', 'name', config_file)

    def get_user_email(self, config_file=None):

        """

        Returns user's email from global configuration file.

        :param config_file: A path to file which should be used to retrieve

          configuration from (might also be a list of file paths)

        """

        return self.get_config_value('user', 'email', config_file)