pygments.php

<?php

/*
Plugin Name: Pygments Support
Plugin URI: http://lucumr.pocoo.org/
Description: Adds support for pygments to wordpress
Version: 1.0
Author: Armin Ronacher
Author URI: http://lucumr.pocoo.org/

Modified by Christophe Grand to support wordpress 2.8
*/

define('PYGMENTS_STYLE', 'pastie');
define('PYGMENTS_PATH', '/usr/bin/pygmentize');


/**
 * function that highlights code in a pygments
 * subprocess and returns the highlighted HTML.
 *
 * return NULL if something went wrong.
 */
function pygments_highlight_code($tag, $code, $lexer)
{
	if (!preg_match('/^[a-zA-Z_+]+$/', $lexer))
		return NULL;

	$pipes = NULL;
	$process = proc_open(PYGMENTS_PATH . ' -l' . $lexer . ' -fhtml -Onowrap,style=' .
	                     PYGMENTS_STYLE, array(
		array('pipe', 'r'),
		array('pipe', 'w'),
		array('pipe', 'w')
	), $pipes);
	
	fwrite($pipes[0], $code);
	fclose($pipes[0]);

	$highlighted = rtrim(stream_get_contents($pipes[1]));
	fclose($pipes[1]);

	$errors = stream_get_contents($pipes[2]);
	fclose($pipes[2]);
	if (trim($errors))
		return NULL;

	proc_close($process);
	return '<' . $tag . ' class="highlight">' . addcslashes($highlighted, '\\') . '</' . $tag . '>';
}

/**
 * this function is called to remove the cached stuff from the post
 * if the post was edited. This ensures that the cached output is not
 * visible in the editor and that you can edit the post after posting.
 */
function pygments_cleanup_code($text)
{
	// Step 1: remove the cached stuff
	$regex = '/&lt;!-- PYGMENTS_CACHE&gt;.*?&lt;PYGMENTS_CACHE --&gt;/sm';
	$text = preg_replace($regex, '', $text);

	// Step 2: remove the comments around the raw stuff
	// and recreate the <pre lang=""></pre> stuff.
	$regex = '/&lt;!-- PYGMENTS_RAW\\(([^,)]+),?\\s*([^)]*)\\)&gt;(.*?)&lt;PYGMENTS_RAW --&gt;/sm';
	return preg_replace_callback($regex, '_pygments_perform_cleanup', $text);	
}

function _pygments_perform_cleanup($match)
{
	$tag = $match[2] == "" ? "pre" : $match[2];
	return '<' . $tag . ' lang="' . $match[1] . '">' . $match[3] . '</' . $tag . '>';	
}

/**
 * the opposite of the pygments_cleanup_code. It's executed when
 * rendering the blog post and just removes the raw stuff because we
 * don't want a bloated page.
 */
function pygments_finish_code($text)
{
	// Step 1: uncomment the cache
	$regex = '/<!-- PYGMENTS_CACHE>(.*?)<PYGMENTS_CACHE -->/sm';
	$text = preg_replace($regex, '\\1', $text);

	// Step 2: remove all the raw stuff
	$regex = '/<!-- PYGMENTS_RAW\\(.*?<PYGMENTS_RAW -->/sm';
	return preg_replace($regex, '', $text);
}

/**
 * highlight the code inline. All the pre tags with a language tag
 * are processed by pygments then.
 */
function pygments_highlight_code_inline($text)
{
	// Find all the pre or code blocks with a lang attribute
	$regex = '/<(pre|code)\\s+lang=\\\\(["\'])([^\\\\]+)\\\\\\2>(.*?)<\\/\\1>/ism';
	return preg_replace_callback($regex, '_pygments_perform_replace', $text);
}

/**
 * helper function (callback) for pygments_highlight_code_inline
 */
function _pygments_perform_replace($match)
{
	$lang = strtolower($match[3]);
	$code = $match[4];
	$highlighted = pygments_highlight_code($match[1], stripslashes($code), $lang);
	if (!$highlighted)
		$highlighted = '<' . $match[1] . '>' . htmlspecialchars($code) . '</' . $match[1] . '>';
	return '<!-- PYGMENTS_CACHE>' . $highlighted . '<PYGMENTS_CACHE -->' .
	       '<!-- PYGMENTS_RAW(' . $lang . ', ' . $match[1] . ')>' . $code . '<PYGMENTS_RAW -->';
}

// register filters in wordpress
add_filter('the_editor_content', 'pygments_cleanup_code', 100);
add_filter('content_save_pre', 'pygments_highlight_code_inline', 1);
add_filter('the_content', 'pygments_finish_code', 1);