Make Minify_CSS_Compressor class static

[sedimentation-fault]

I fail to see how any method of the Minify_CSS_Compressor class in minify/lib/Minify/CSS/Compressor.php is dependent on the class instance (i.e. on $this). The only place where $this is used is in the callbacks to preg_match_callback:

$css = preg_replace_callback($pattern, array($this, '_selectorsCB'), $css);

but this can be changed to

$css = preg_replace_callback($pattern, array(get_called_class(), '_selectorsCB'), $css);

Just remember to initialize the one and only true property _inHack(_options is not used anyway) like this

		// Initialize!
		self::$_inHack = false;

in function _process(). Then you can declare all methods static and refer to $_inHack with self::$_inHack. There is nothing more to it - simple. 😉

WHY

You spare an instantiation of Minify_CSS_Compressor each time a script minifies a CSS. In high-traffic scenarios, this might make a measurable difference.