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/**
* Compress Javascript/CSS using the GoogleClosure
*
* You must set $jarFile and $tempDir before calling the minify functions.
* Also, depending on your shell's environment, you may need to specify
* the full path to java in $javaExecutable or use putenv() to setup the
* Java environment.
*
*
* @package Minify
*/
class Minify_GoogleClosure {

    /**
     * Filepath of the Google Closure jar file. This must be set before
     * calling minifyJs() or minifyCss().
     *
     * @var string
     */
    public static $jarFile = null;

    /**
     * Writable temp directory. This must be set before calling minifyJs()
     * or minifyCss().
     *
     * @var string
     */
    public static $tempDir = null;

    /**
     * Filepath of "java" executable (may be needed if not in shell's PATH)
     *
     * @var string
     */
    public static $javaExecutable = 'java';

    /**
     * Minify a Javascript string
     *
     * @param string $js
     *
     * @param array $options (verbose is ignored)
     *
     * @return string
     */
    public static function minifyJs($js, $options = array())
    {
        return self::_minify('js', $js, $options);
    }

    /**
     * Minify a CSS string
     *
     * @param string $css
     *
     * @param array $options (verbose is ignored)
     *
     * @return string
     */
    public static function minifyCss($css, $options = array())
    {
        return self::_minify('css', $css, $options);
    }

    private static function _minify($type, $content, $options)
    {
        self::_prepare();
        if (! ($tmpFile = tempnam(self::$tempDir, 'googlec_'))) {
            throw new Exception('Minify_GoogleClosure : could not create temp file.');
        }
        file_put_contents($tmpFile, $content);
        exec(self::_getCmd($options, $type, $tmpFile), $output);
        unlink($tmpFile);
        return implode("\n", $output);
    }

    private static function _getCmd($userOptions, $type, $tmpFile)
    {
        $cmd = self::$javaExecutable . ' -jar ' . escapeshellarg(self::$jarFile);
        return $cmd . ' --js ' . escapeshellarg($tmpFile);
    }