evidence on how *slow* and inefficient qTranslate is … please do something

I’m going to use this thread to post code optimizations that I do to qTranslate for anyone who is interested.

You can also make the qtrans_parseURL() function faster, in qtranslate_utils.php. This function is called quite a few times:

function qtrans_parseURL($url) {
    $r  = '!(?:(\w+)://)?(?:(\w+)\:(\w+)@)?([^/:]+)?';
    $r .= '(?:\:(\d*))?([^#?]+)?(?:\?([^#]+))?(?:#(.+$))?!i';

    preg_match ( $r, $url, $out );
    $result = @array(
        "scheme" => $out[1],
        "host" => $out[4].(($out[5]=='')?'':':'.$out[5]),
        "user" => $out[2],
        "pass" => $out[3],
        "path" => $out[6],
        "query" => $out[7],
        "fragment" => $out[8]
        );
    return $result;
}

Even though the above could be sped up by using the S PCRE modifier to analyze the regex for future calls, you can replace the entire function with the much faster:

function qtrans_parseURL($url) {
        $result = parse_url($url) + array(
                'scheme' => '',
                'host' => '',
                'user' => '',
                'pass' => '',
                'path' => '',
                'query' => '',
                'fragment' => ''
        );
        isset($result['port'])
                and $result['host'] .= ':'. $result['port'];
        return $result;
}

note the + array union operator which basically implements default array values since parse_url() populates those array fields only if a match was found in the url.

Actually, most of the above is not needed. In fact, the second if (is_array() ... is not even reached if $text is an array or object, which is Ok in most cases, see below. You could just as well remove it altogether.

The qtrans_postsFilter() function is hooked into ‘the_posts’ filter. This function is:

function qtrans_postsFilter($posts) {
	if(is_array($posts)) {
		foreach($posts as $post) {
			$post->post_content = qtrans_useCurrentLanguageIfNotFoundShowAvailable($post->post_content);
			$post = qtrans_useCurrentLanguageIfNotFoundUseDefaultLanguage($post);
		}
	}
	return $posts;
}

Note how it is passing each object $post in a loop to qtrans_useCurrentLanguageIfNotFoundUseDefaultLanguage($post) which in turn calls qtrans_use() on each of the object’s properties. Only the title and content (and maybe guid and pinged) properties require translation (none of the other 20+ do) and for those, qTranslate already hooks into ‘the_content’, ‘the_title’ etc filters. This function can be useful if you call get_posts() in your own code.

You could remove the ‘the_posts’ hook from qtranslate_hooks.php and if you need to call get_posts() in your own code and want the title and content translated, then you can either call qtrans_postsFilter(), which is very inefficient (and you may not want the default behaviour of not showing the default language for the content if the current language is unavailable), of just translate the title and content in a loop — you can have your own function for that.

To keep current functionality but with a faster, less-recursive function, replace in qtrans_use() the following:

global $q_config;
// return full string if language is not enabled
if(!qtrans_isEnabled($lang)) return $text;
if(is_array($text)) {
    // handle arrays recursively
    foreach($text as $key => $t) {
        $text[$key] = qtrans_use($lang,$text[$key],$show_available);
    }
    return $text;
}

if (is_object($text)||@get_class($text) == '__PHP_Incomplete_Class') {
    foreach(get_object_vars($text) as $key => $t) {
        $text->$key = qtrans_use($lang,$text->$key,$show_available);
    }
    return $text;
}

// prevent filtering weird data types and save some resources
if(!is_string($text) || $text == '') {
    return $text;
}

with the following

if (empty($text) || !qtrans_isEnabled($lang))
    return $text;

$re = '/<!--:[a-z]{2}-->/';
if (is_string($text) && !preg_match($re, $text))
    return $text;

if (is_array($text) || is_object($text)) {
    foreach ($text as &$t)
        if ($t && ((is_string($t) && preg_match($re, $t)) || is_array($t) || is_object($t)))
            $t = qtrans_use($lang, $t, $show_available);
    return $text;
}

global $q_config;