~azzar1/unity/add-show-desktop-key

# IVLE - Informatics Virtual Learning Environment

# Copyright (C) 2007-2009 The University of Melbourne

#

# 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 2 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, write to the Free Software

# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

# Author: Nick Chadwick, Will Grant

import os

import inspect

import genshi

from ivle.webapp.base.xhtml import GenshiLoaderMixin

class BaseOverlay(object):

    """Abstract base class for all overlays."""

    plugin_scripts = {}

    plugin_styles = {}

    plugin_scripts_init = []

    def __init__(self, req):

        self.req = req

    def render(self, req):

        raise NotImplementedError()

class XHTMLOverlay(GenshiLoaderMixin, BaseOverlay):

    """Abstract base class for XHTML overlays.

    An overlay which provides a base class for overlays which need to return 

    XHTML. It is expected that apps which use this overlay will be written using

    Genshi templates.

    """

    template = 'template.html'

    def render(self, req):

        """Renders an XML stream from the template for this overlay."""

        ctx = genshi.template.Context()

        # This is where the sub-class is actually called

        self.populate(req, ctx)

        # Renders out the template.

        template_path = os.path.join(os.path.dirname(

                        inspect.getmodule(self).__file__), self.template)

        tmpl = self._loader.load(template_path)

        return tmpl.generate(ctx)

    def populate(self, req, ctx):

        raise NotImplementedError()