Magento merged CS/JSS improvements

Package.php

<?php
/**
 * Magento
 *
 * NOTICE OF LICENSE
 *
 * This source file is subject to the Open Software License (OSL 3.0)
 * that is bundled with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://opensource.org/licenses/osl-3.0.php
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@magentocommerce.com so we can send you a copy immediately.
 *
 * DISCLAIMER
 *
 * Do not edit or add to this file if you wish to upgrade Magento to newer
 * versions in the future. If you wish to customize Magento for your
 * needs please refer to http://www.magentocommerce.com for more information.
 *
 * @category    Mage
 * @package     Mage_Core
 * @copyright   Copyright (c) 2010 Magento Inc. (http://www.magentocommerce.com)
 * @license     http://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
 */


class Template_Core_Model_Design_Package extends Mage_Core_Model_Design_Package
{
    const CACHE_KEY = 'design_merged';
    const CACHE_TAG = 'design_merged';

    protected $_locked = FALSE;

    protected $_baseMergedUrl;

    /**
     * Merge specified css files and return URL to the merged file on success
     *
     * @param $files
     * @return string
     */
    public function getMergedCssUrl($files)
    {
        // Find the most recent modified time of all files to include in target filename hash so that
        // modifications invalidate browser's caching
        $filenamesHash = md5(implode(',', $files));
        $newestCacheKey = 'DESIGN_NEWEST_CSS_'.$filenamesHash;
        if( ! Mage::app()->useCache(self::CACHE_KEY) || ! ($newest = Mage::app()->loadCache($newestCacheKey))) {
            $newest = 0;
            foreach($files as $file) {
              $mtime = filemtime($file);
              if($mtime > $newest) $newest = $mtime;
            }
            Mage::app()->saveCache($newest, $newestCacheKey, array(self::CACHE_TAG));
        }
        $targetFilename = md5(implode('-',array(
          Mage::getBaseUrl('skin'), // In case skin url is updated
          $filenamesHash,           // In case file is added or removed
          $newest,                  // In case file is updated
          isset($_SERVER['HTTPS']), // Vary for http/https in skin image urls
        )));
        $targetDir = $this->_initMergerDir('css');
        if (!$targetDir) {
            return '';
        }
        $targetPath = $targetDir . DS . $targetFilename;

        // Check for minified version (minified by external app)
        if(file_exists($targetPath.'-min.css')) {
            return $this->_getBaseMergedUrl() . 'css/' . $targetFilename.'-min.css';
        }
        // Check for non-minified version
        else if(file_exists($targetPath.'.css')) {
            return $this->_getBaseMergedUrl() . 'css/' . $targetFilename.'.css';
        }

        // Files need to be merged
        if (Mage::helper('core')->mergeFiles($files, $targetPath.'.css', false, array($this, 'beforeMergeCss'), 'css')) {
            return $this->_getBaseMergedUrl() . 'css/' . $targetFilename.'.css';
        }
        return '';
     }

    /**
     * Merge specified javascript files and return URL to the merged file on success
     *
     * @param $files
     * @return string
     */
    public function getMergedJsUrl($files)
    {
        // Find the most recent modified time of all files to include in target filename hash so that
        // modifications invalidate browser's caching
        $filenamesHash = md5(implode(',', $files));
        $newestCacheKey = 'DESIGN_NEWEST_JS_'.$filenamesHash;
        if( ! Mage::app()->useCache(self::CACHE_KEY) || ! ($newest = Mage::app()->loadCache($newestCacheKey))) {
            $newest = 0;
            foreach($files as $file) {
              $mtime = filemtime($file);
              if($mtime > $newest) $newest = $mtime;
            }
            Mage::app()->saveCache($newest, $newestCacheKey, array(self::CACHE_TAG));
        }
        $targetFilename = md5(implode('-',array(
          Mage::getBaseUrl('skin'), // In case skin url is updated
          $filenamesHash,           // In case file is added or removed
          $newest,                  // In case file is updated
        )));
        $targetDir = $this->_initMergerDir('js');
        if (!$targetDir) {
            return '';
        }
        $targetPath = $targetDir . DS . $targetFilename;

        // Check for minified version (minified by external app)
        if(file_exists($targetPath.'-min.js')) {
            return $this->_getBaseMergedUrl() . 'js/' . $targetFilename.'-min.js';
        }
        // Check for non-minified version
        else if(file_exists($targetPath.'.js')) {
            return $this->_getBaseMergedUrl() . 'js/' . $targetFilename.'.js';
        }

        // Files need to be merged
        if (Mage::helper('core')->mergeFiles($files, $targetPath.'.js', false, null, 'js')) {
            return $this->_getBaseMergedUrl() . 'js/' . $targetFilename.'.js';
        }
        return '';
    }

    /**
     * Equivalent to Mage::getBaseUrl('merged') without overriding Mage_Core_Model_Store
     *
     * @return string
     */
    protected function _getBaseMergedUrl()
    {
        if( ! $this->_baseMergedUrl) {
            $this->_baseMergedUrl = Mage::app()->getStore()->getConfig(
                'web/'.(Mage::app()->getStore()->isCurrentlySecure() ? 'secure' : 'unsecure').'/base_merged_url'
            );
        }
        return $this->_baseMergedUrl;
    }

    /**
     * Overridden to do nothing since there is never any reason to clean these with the new hashing scheme
     *
     * @return bool
     */
    public function cleanMergedJsCss()
    {
      return TRUE;
    }

    /**
     * Make sure merger dir exists and writeable
     * Also can clean it up
     * MODIFIED to not remove the directory itself since it is watched by inotify
     *
     * @param string $dirRelativeName
     * @param bool $cleanup
     * @return bool|string
     */
    protected function _initMergerDir($dirRelativeName, $cleanup = false)
    {
        try {
            $dir = Mage::getBaseDir('media') . DS . $dirRelativeName;
            if ($cleanup && is_dir($dir)) {
                array_map('unlink', glob("$dir/*.*"));
            }
            if (!is_dir($dir)) {
                mkdir($dir);
            }
            return is_writeable($dir) ? $dir : false;
        } catch (Exception $e) {
            Mage::logException($e);
        }
        return false;
    }


    /**
     * Prepare url for css replacement
     * MODIFIED to use real skin url (for CDN compatibility)
     *
     * @param string $uri
     * @return string
     */
    protected function _prepareUrl($uri)
    {
        // check absolute or relative url
        if (!preg_match('/^[http|https]/i', $uri) && !preg_match('/^\//i', $uri)) {

            $fileDir = '';
            $pathParts = explode(DS, $uri);
            $fileDirParts = explode(DS, $this->_callbackFileDir);

            foreach ($pathParts as $key=>$part) {
                if ($part == '.' || $part == '..') {
                    unset($pathParts[$key]);
                }

                if ($part == '..' && count($fileDirParts)) {
                    $fileDirParts = array_slice($fileDirParts, 0, count($fileDirParts) - 1);
                }
            }

            if (count($fileDirParts)) {
                $fileDir = implode('/', $fileDirParts).'/';
            }

            $uri = $fileDir.implode('/', $pathParts);
            if (substr($uri,0,5) == 'skin/') {
              $uri = Mage::getBaseUrl('skin').substr($uri,5);
            } else {
              $uri = Mage::getBaseUrl('web').$uri;
            }

        }
        return $uri;
    }

    /**
     * Takes one or two parameters (set all or set one type)
     *
     * Overridden to allow a theme to be "locked", so that later code cannot override the theme (e.g. for mobile version)
     *
     * @return \Template_Core_Model_Design_Package
     */
    public function setTheme()
    {
        if($this->_locked) {
            return $this;
        }
        switch (func_num_args()) {
            case 1:
                foreach (array('layout', 'template', 'skin', 'locale') as $type) {
                    $this->_theme[$type] = func_get_arg(0);
                }
                break;

            case 2:
                $this->_theme[func_get_arg(0)] = func_get_arg(1);
                break;

            default:
                throw Mage::exception(Mage::helper('core')->__('Wrong number of arguments for %s', __METHOD__));
        }
        return $this;
    }

    /**
     * Overridden to allow a package to be "locked", so that later code cannot override the theme (e.g. for mobile version)
     *
     * @param  string $name
     * @return Mage_Core_Model_Design_Package
     */
    public function setPackageName($name = '')
    {
        if($this->_locked) {
            return $this;
        }
        return parent::setPackageName($name);
    }

    /**
     * Locks the theme and package to the existing theme and package
     */
    public function lockPackageTheme()
    {
        $this->_locked = TRUE;
    }

}