def __before__(self):

        super(CompareController, self).__before__()

    def _handle_ref(self, ref):

        """

        Parse the org...other string

        Possible formats are 

            `(branch|book|tag):<name>...(branch|book|tag):<othername>`

        :param ref: <orginal_reference>...<other_reference>

        :type ref: str

        """

        def org_parser(org):

            _repo = org_repo

            name, val = org.split(':')

            return _repo, (name, val)

        def other_parser(other):

            _other_repo = request.GET.get('repo')

            _repo = org_repo

            name, val = other.split(':')

            if _other_repo:

                _repo = _other_repo

            return _repo, (name, val)

        if '...' in ref:

            try:

                org, other = ref.split('...')

                org_repo, org_ref = org_parser(org)

                other_repo, other_ref = other_parser(other)

                return org_repo, org_ref, other_repo, other_ref

            except:

                log.error(traceback.format_exc())

        raise HTTPNotFound

        from mercurial import discovery

        other = org_repo._repo

        repo = other_repo._repo

        tmp = discovery.findcommonincoming(

                  repo=repo,  # other_repo we check for incoming

                  remote=other,  # org_repo source for incoming

                  force=False

        )

        return tmp

    def _get_changesets(self, org_repo, org_ref, other_repo, other_ref, tmp):

        changesets = []

        #case two independent repos

        if org_repo != other_repo:

            common, incoming, rheads = tmp

            if not incoming:

                revs = []

        else:

            revs = ['ancestors(%s) and not ancestors(%s)' % (org_ref[1],

                                                             other_ref[1])]

            from mercurial import scmutil

            out = scmutil.revrange(org_repo._repo, revs)

            for cs in reversed(out):

                changesets.append(org_repo.get_changeset(cs))

        return changesets

    def index(self, ref):

        org_repo, org_ref, other_repo, other_ref = self._handle_ref(ref)

        c.swap_url = h.url('compare_home', repo_name=other_repo,

                           ref='%s...%s' % (':'.join(other_ref),

                                            ':'.join(org_ref)),

                           repo=org_repo)

        c.org_repo = org_repo = Repository.get_by_repo_name(org_repo)

        c.other_repo = other_repo = Repository.get_by_repo_name(other_repo)

                                           org_ref,

                                           other_repo.scm_instance,

                                           other_ref)

        c.cs_ranges = self._get_changesets(org_repo.scm_instance,

                                           org_ref,

                                           other_repo.scm_instance,

                                           other_ref,

        c.org_ref = org_ref[1]

        c.other_ref = other_ref[1]

        # diff needs to have swapped org with other to generate proper diff

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

        _parsed = diff_processor.prepare()

        c.files = []

        c.changes = {}

        # sort Added first then Modified last Deleted files

        sorter = lambda info: {'A': 0, 'M': 1, 'D': 2}.get(info['operation'])

        for f in sorted(_parsed, key=sorter):

            fid = h.FID('', f['filename'])

            c.files.append([fid, f['operation'], f['filename'], f['stats']])

            diff = diff_processor.as_html(enable_comments=False, diff_lines=[f])

            c.changes[fid] = [f['operation'], f['filename'], diff]

        _html.append('''</table>''')

        if _html_empty:

            return None

        return ''.join(_html)

    def stat(self):

        """

        Returns tuple of added, and removed lines for this instance

        """

        return self.adds, self.removes

def differ(org_repo, org_ref, other_repo, other_ref, discovery_data=None):

    """

    General differ between branches, bookmarks or separate but releated 

    repositories

    :param org_repo:

    :type org_repo:

    :param org_ref:

    :type org_ref:

    :param other_repo:

    :type other_repo:

    :param other_ref:

    :type other_ref:

    """

    context = 3

    org_repo = org_repo.scm_instance._repo

    other_repo = other_repo.scm_instance._repo

    opts = diffopts(git=True, ignorews=ignore_whitespace, context=context)

    org_ref = org_ref[1]

    other_ref = other_ref[1]

    if org_repo != other_repo:

        common, incoming, rheads = discovery_data

        # create a bundle (uncompressed if other repo is not local)

            # disable repo hooks here since it's just bundle !

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

            # hooks on fetching archives with subrepos

            for k, _ in other_repo.ui.configitems('hooks'):

                other_repo.ui.setconfig('hooks', k, None)

            unbundle = other_repo.getbundle('incoming', common=common,

                                            heads=rheads)

            buf = io.BytesIO()

            while True:

                chunk = unbundle._stream.read(1024*4)

                if not chunk:

                    break

                buf.write(chunk)

            buf.seek(0)

            unbundle._stream = buf

    else:

        return ''.join(patch.diff(org_repo, node1=org_ref, node2=other_ref,

                                  opts=opts))

<%def name="page_nav()">

    ${self.menu('branches')}

</%def>

<%def name="main()">

<div class="box">

    <!-- box / title -->

    <div class="title">

        ${self.breadcrumbs()}

    </div>

    <!-- end box / title -->

    <div class="info_box" id="compare_branches" style="clear: both;padding: 10px 19px;vertical-align: right;text-align: right;"><a href="#" class="ui-btn small">${_('Compare branches')}</a></div>

    <div class="table">

        <%include file='branches_data.html'/>

    </div>

</div>

<script type="text/javascript">

YUE.on('compare_branches','click',function(e){

	YUE.preventDefault(e);

	var org = YUQ('input[name=compare_org]:checked')[0];

	var other = YUQ('input[name=compare_other]:checked')[0];

	var compare_url = "${h.url('compare_home',repo_name=c.repo_name,ref='__ORG__...__OTHER__')}";

	if(org && other){

		var u = compare_url.replace('__ORG__','branch:'+org.value)

    ${self.menu('changelog')}

</%def>

<%def name="main()">

<div class="box">

    <!-- box / title -->

    <div class="title">

        ${self.breadcrumbs()}

    </div>

    <div class="table">

        <div id="body" class="diffblock">

            <div class="code-header cv">

                <div>

                </div>

            </div>

        </div>

        <div id="changeset_compare_view_content">

            <div class="container">

            <table class="compare_view_commits noborder">

            %for cnt, cs in enumerate(c.cs_ranges):

                <tr>

                <td><div class="gravatar"><img alt="gravatar" src="${h.gravatar_url(h.email(cs.author),14)}"/></div></td>

                <td>${h.link_to('r%s:%s' % (cs.revision,h.short_id(cs.raw_id)),h.url('changeset_home',repo_name=c.repo_name,revision=cs.raw_id))}</td>

                <td><div class="author">${h.person(cs.author)}</div></td>

                <td><span class="tooltip" title="${h.age(cs.date)}">${cs.date}</span></td>