Changes to Annotum Wordpress theme to support ePub Export Plugin

anno-xml-download.php

/**
 * Get the ePub download link for a post
 *
 * @param int $id 
 * @return string
 */
function anno_epub_download_url($id = null) {
  # Requires ePub Export Plugin, returns "" if ePub Export Plugin didn't create ePub file
  $article_id = get_the_ID();
  $uploads = wp_upload_dir();
  $fname = $uploads[path] . "/" . $article_id . ".epub";
  // Use link if ePub exists
  if (file_exists($fname)) {
    $url = $uploads[url] . "/" . $article_id . ".epub";
  } else {
    $url = "";
  }
	return $url;
}

tools-bar.php

 // Set a default ePub Link
$epub_link = '';
if (function_exists('anno_epub_download_url')) {
	$epub_url = anno_epub_download_url(get_the_ID());
	if (!empty($epub_url)) {
		$epub_link = '<a href="'.esc_url($epub_url).'">'.__('ePub', 'anno').'</a>';
	}
}
?>
<div class="tools-bar supplement clearfix">
	<div class="cell print">
		<a href="#" onclick="window.print(); return false;"><?php _e('Print Article', 'anno'); ?></a>
	</div>
	<div class="cell citation">
		<a><?php _e('Citation', 'anno'); ?></a>
		<div class="citation-container">
			<textarea class="entry-summary" readonly><?php anno_the_citation(); ?></textarea>
		</div><!--/.citation-container -->
	</div>
	<div class="cell download">
		<?php echo implode(', ', array($pdf_link, $xml_link, $epub_link)); ?> 
	</div>
	<div class="cell share clearfix">
		<div class="social-nav">
			<ul class="nav">
				<li><?php anno_email_link(); ?></li>
				<li><?php anno_twitter_button(); ?></li>
				<li><?php anno_facebook_button(); ?></li>
			</ul>
		</div>
	</div>
</div><!-- .action-bar -->