<?php
/**
 * Class Minify_ClosureCompiler
 * @package Minify
 */

/**
 * Compress Javascript using the Closure Compiler
 *
 * 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 $javaExecutable or use putenv() to setup the
 * Java environment.
 *
 * <code>
 * Minify_ClosureCompiler::$jarFile = '/path/to/closure-compiler-20120123.jar';
 * Minify_ClosureCompiler::$tempDir = '/tmp';
 * $code = Minify_ClosureCompiler::minify(
 * $code,
 * array('compilation_level' => 'SIMPLE_OPTIMIZATIONS')
 * );
 *
 * --compilation_level WHITESPACE_ONLY, SIMPLE_OPTIMIZATIONS, ADVANCED_OPTIMIZATIONS
 *
 * </code>
 *
 * @todo unit tests, $options docs
 * @todo more options support (or should just passthru them all?)
 *
 * @package Minify
 * @author Stephen Clay <steve@mrclay.org>
 * @author Elan Ruusamäe <glen@delfi.ee>
 */
class Minify_ClosureCompiler {

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

 /**
 * Writable temp directory. This must be set before calling minifyJs().
 *
 * @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 $options (verbose is ignored)
 *
 * @see https://code.google.com/p/closure-compiler/source/browse/trunk/README
 *
 * @return string
 */
 public static function minify($js, $options = array())
 {
 self::_prepare();
 if (! ($tmpFile = tempnam(self::$tempDir, 'cc_'))) {
 throw new Exception('Minify_ClosureCompiler : could not create temp file.');
 }
 file_put_contents($tmpFile, $js);
 exec(self::_getCmd($options, $tmpFile), $output, $result_code);
 unlink($tmpFile);
 if ($result_code != 0) {
 throw new Exception('Minify_ClosureCompiler : Closure Compiler execution failed.');
 }
 return implode("\n", $output);
 }

 private static function _getCmd($userOptions, $tmpFile)
 {
 $o = array_merge(
 array(
 'charset' => 'utf-8',
 'compilation_level' => 'SIMPLE_OPTIMIZATIONS',
 ),
 $userOptions
 );
 $cmd = self::$javaExecutable . ' -jar ' . escapeshellarg(self::$jarFile)
 . (preg_match('/^[\\da-zA-Z0-9\\-]+$/', $o['charset'])
 ? " --charset {$o['charset']}"
 : '');

 foreach (array('compilation_level') as $opt) {
 if ($o[$opt]) {
 $cmd .= " --{$opt} ". escapeshellarg($o[$opt]);
 }
 }
 return $cmd . ' ' . escapeshellarg($tmpFile);
 }

 private static function _prepare()
 {
 if (! is_file(self::$jarFile)) {
 throw new Exception('Minify_ClosureCompiler : $jarFile('.self::$jarFile.') is not a valid file.');
 }
 if (! is_readable(self::$jarFile)) {
 throw new Exception('Minify_ClosureCompiler : $jarFile('.self::$jarFile.') is not readable.');
 }
 if (! is_dir(self::$tempDir)) {
 throw new Exception('Minify_ClosureCompiler : $tempDir('.self::$tempDir.') is not a valid direcotry.');
 }
 if (! is_writable(self::$tempDir)) {
 throw new Exception('Minify_ClosureCompiler : $tempDir('.self::$tempDir.') is not writable.');
 }
 }
}

/* vim:ts=4:sw=4:et */