def transform(odtfile, debug=False, parsable=False, outputdir=None):
    """ Given an ODT file this returns a tuple containing
        the cnxml, a dictionary of filename -> data, and a list of errors """
    # Store mapping of images extracted from the ODT file (and their bits)
    images = {}
    # Log of Errors and Warnings generated
    # For example, the text produced by XSLT should be:
    # {'level':'WARNING',
    #  'msg'  :'Headings without text between them are not allowed',
    #  'id'   :'import-auto-id2376'}
    # That way we can put a little * near all the cnxml where issues arose
    errors = []

    zip = zipfile.ZipFile(odtfile, 'r')
    content = zip.read('content.xml')
    xml = etree.fromstring(content)

    def appendLog(xslDoc):
        if hasattr(xslDoc, 'error_log'):
            for entry in xslDoc.error_log:
                # Entries are of the form:
                # {'level':'ERROR','id':'id1234','msg':'Descriptive message'}
                text = entry.message
                try:
                    dict = json.loads(text)
                    errors.append(dict)
                except ValueError:
                    errors.append({
                      u'level':u'CRITICAL',
                      u'id'   :u'(none)',
                      u'msg'  :unicode(text) })
                    
    def injectStyles(xml):
        # HACK - need to find the object location from the manifest ...
        strStyles = zip.read('styles.xml')
        
        parser = etree.XMLParser()
        parser.feed(strStyles)
        stylesXml = parser.close()
        
        for i, obj in enumerate(STYLES_XPATH(stylesXml)):
          xml.append(obj)

        return xml


    # All MathML is stored in separate files "Object #/content.xml"
    # This converter includes the MathML by looking up the file in the zip
    def mathIncluder(xml):
        for i, obj in enumerate(MATH_XPATH(xml)):
            strMathPath = MATH_HREF_XPATH(obj)[0] # Or obj.get('{%s}href' % XLINK_NS)
            if strMathPath[0] == '#':
                strMathPath = strMathPath[1:]
            # Remove leading './' Zip doesn't like it
            if strMathPath[0] == '.':
                strMathPath = strMathPath[2:]

            # HACK - need to find the object location from the manifest ...
            strMathPath = os.path.join(strMathPath, 'content.xml')
            strMath = zip.read(strMathPath)
            
            #parser = etree.XMLParser(encoding='utf-8')
            #parser.feed(strMath)
            #math = parser.close()
            math = etree.parse(StringIO(strMath)).getroot()
            
            # Replace the reference to the Math with the actual MathML
            obj.getparent().replace(obj, math)
        return xml

    def imagePuller(xml):
        for i, obj in enumerate(IMAGE_XPATH(xml)):
            strPath = IMAGE_HREF_XPATH(obj)[0]
            strName = IMAGE_NAME_XPATH(obj)[0]

            fileNeedEnding = ( strName.find('.') == -1 )
            if fileNeedEnding:
                strName = strName + strPath[strPath.index('.'):]

            if strPath[0] == '#':
                strPath = strPath[1:]
            # Remove leading './' Zip doesn't like it
            if strPath[0] == '.':
                strPath = strPath[2:]

            image = zip.read(strPath)
            images[strName] = image
            
            # Later on, an XSL pass will convert the draw:frame to a c:image and 
            # set the @src correctly

        return xml
        
    def drawPuller(xml):
        styles = DRAW_STYLES_XPATH(xml)
                       
        empty_odg_dirname = os.path.join(dirname, 'empty_odg_template')
        
        temp_dirname = tempfile.mkdtemp()
            
        for i, obj in enumerate(DRAW_XPATH(xml)):
            # Copy everything except content.xml from the empty ODG (OOo Draw) template into a new zipfile
            
            odg_filename = DRAW_FILENAME_PREFIX + str(i) + '.odg'
            png_filename = DRAW_FILENAME_PREFIX + str(i) + '.png'

            # add PNG filename as attribute to parent node. The good thing is: The child (obj) will get lost! :-)
            parent = obj.getparent()
            parent.attrib['ooo_drawing'] = png_filename
            
            odg_zip = zipfile.ZipFile(os.path.join(temp_dirname, odg_filename), 'w', zipfile.ZIP_DEFLATED)
            for root, dirs, files in os.walk(empty_odg_dirname):
                for name in files:
                    if name not in ('content.xml', 'styles.xml'):   # copy everything inside ZIP except content.xml or styles.xml
                        sourcename = os.path.join(root, name)
                        # http://stackoverflow.com/a/1193171/756056                        
                        arcname = os.path.join(root[len(empty_odg_dirname):], name)  # Path name inside the ZIP file, empty_odg_template is the root folder
                        odg_zip.write(sourcename, arcname)
            
            content = etree.parse(os.path.join(empty_odg_dirname, 'content.xml'))
                           
            # Inject content styles in empty OOo Draw content.xml
            content_style_xpath = etree.XPath('/office:document-content/office:automatic-styles', namespaces=NAMESPACES)
            content_styles = content_style_xpath(content)                                
            for style in styles:
                content_styles[0].append(deepcopy(style))
            
            # Inject drawing in empty OOo Draw content.xml
            content_page_xpath = etree.XPath('/office:document-content/office:body/office:drawing/draw:page', namespaces=NAMESPACES)
            content_page = content_page_xpath(content)
            content_page[0].append(obj)
            
            # write modified content.xml
            odg_zip.writestr('content.xml', etree.tostring(content, xml_declaration=True, encoding='UTF-8'))
            
            # copy styles.xml from odt to odg without modification
            styles_xml = zip.read('styles.xml')
            odg_zip.writestr('styles.xml', styles_xml)

            odg_zip.close()
            
            # TODO: Better error handling in the future.
            try:
                # convert every odg to png
                command = '/usr/bin/soffice -headless -nologo -nofirststartwizard "macro:///Standard.Module1.SaveAsPNG(%s,%s)"' % (os.path.join(temp_dirname, odg_filename),os.path.join(temp_dirname, png_filename))
                os.system(command)

                # save every image to memory            
                image = open(os.path.join(temp_dirname, png_filename), 'r').read()
                images[png_filename] = image
                
                if outputdir is not None:
                    shutil.copy (os.path.join(temp_dirname, odg_filename), os.path.join(outputdir, odg_filename))
                    shutil.copy (os.path.join(temp_dirname, png_filename), os.path.join(outputdir, png_filename))
            except:
                pass
                
        # delete temporary directory
        shutil.rmtree(temp_dirname)
        
        return xml

    # Reparse after XSL because the RED-escape pass injects arbitrary XML
    def redParser(xml):
        xsl = makeXsl('pass1_odt2red-escape.xsl')
        result = xsl(xml)
        appendLog(xsl)
        try:
            xml = etree.fromstring(etree.tostring(result))
        except etree.XMLSyntaxError, e:
            msg = str(e)
            xml = makeXsl('pass1_odt2red-failed.xsl')(xml, message="'%s'" % msg.replace("'", '"'))
            xml = xml.getroot()
        return xml

    def replaceSymbols(xml):
        xmlstr = etree.tostring(xml)
        xmlstr = symbols.replace(xmlstr)
        return etree.fromstring(xmlstr)

    PIPELINE = [
      drawPuller, # gets OOo Draw objects out of odt and generate odg (OOo Draw) files
      replaceSymbols,
      injectStyles, # include the styles.xml file because it contains list numbering info
      makeXsl('pass2_odt-normalize.xsl'), # This needs to be done 2x to fix headings       
      makeXsl('pass2_odt-normalize.xsl'), # In the worst case all headings are 9 
                            # and need to be 1. See (testbed) southwood__Lesson_2.doc
      makeXsl('pass2_odt-collapse-spans.xsl'), # Collapse adjacent spans (for RED)
      redParser, # makeXsl('pass1_odt2red-escape.xsl'),
      makeXsl('pass4_odt-headers.xsl'),
      imagePuller, # Need to run before math because both have a <draw:image> (see xpath)
      mathIncluder,
      makeXsl('pass7_odt2cnxml.xsl'),
      makeXsl('pass8_cnxml-cleanup.xsl'),
      makeXsl('pass8.5_cnxml-cleanup.xsl'),
      makeXsl('pass9_id-generation.xsl'),
      makeXsl('pass10_processing-instruction-logger.xsl'),
      ]

    # "xml" variable gets replaced during each iteration
    passNum = 0
    for xslDoc in PIPELINE:
        if debug: errors.append("DEBUG: Starting pass %d" % passNum)
        xml = xslDoc(xml)

        appendLog(xslDoc)
        if outputdir is not None: writeXMLFile(os.path.join(outputdir, 'pass%d.xml' % passNum), xml)
        passNum += 1

    # In most cases (EIP) Invalid XML is preferable over valid but Escaped XML
    if not parsable:
      xml = (makeXsl('pass11_red-unescape.xsl'))(xml)

    return (xml, images, errors)
Given an ODT file this returns a tuple containing
        the cnxml, a dictionary of filename -> data, and a list of errors