JsMinifier.php

<?php

namespace Drupal\advagg_js_minify\Asset;

use Drupal\Component\Utility\Unicode;
use Drupal\advagg\Asset\SingleAssetOptimizerBase;
use Drupal\Core\Config\ConfigFactoryInterface;
use Drupal\Core\StringTranslation\StringTranslationTrait;
use Psr\Log\LoggerInterface;

/**
 * Optimizes a JavaScript asset.
 */
class JsMinifier extends SingleAssetOptimizerBase {
    use StringTranslationTrait;
    
    /**
     * Construct the optimizer instance.
     *
     * @param \Psr\Log\LoggerInterface $logger
     *   The logger service.
     * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
     *   A config factory for retrieving required config objects.
     */
    public function __construct(LoggerInterface $logger, ConfigFactoryInterface $config_factory) {
        parent::__construct($logger);
        $this->config = $config_factory->get('advagg_js_minify.settings');
    }
    
    /**
     * {@inheritdoc}
     */
    public function optimize($contents, array $asset, array $data) {
        // Do nothing if js file minification is disabled.
        if (!($minifier = $this->config
            ->get('minifier'))) {
            return $contents;
        }
        // Do not re-minify if the file is already minified.
        if ($this->isMinified($contents)) {
            return $contents;
        }
        $this->clean($contents, $asset);
        $contents_original = $contents;
        $function = $this->getFunction($minifier);
        if (!is_callable($function)) {
            return $contents;
        }
        $arguments = [
            &$contents,
            $asset['data'],
        ];
        call_user_func_array($function, $arguments);
        $contents = trim($contents);
        // Ensure that $data ends with ; or }.
        if (strpbrk(substr(trim($contents), -1), ';})') === FALSE) {
            $contents .= ';';
        }
        if (!$this->isMinificationSuccess($contents, $contents_original)) {
            return $contents_original;
        }
        return $contents;
    }
    
    /**
     * Get the function to use.
     *
     * @param int $minifier
     *   Configuration value.
     *
     * @return callable
     *   the callable to minify the contents.
     */
    protected function getFunction($minifier) {
        $functions = [
            1 => [
                $this,
                'minifyJsminplus',
            ],
            2 => [
                $this,
                'minifyJspacker',
            ],
            3 => [
                $this,
                'minifyJsmin',
            ],
            4 => [
                $this,
                'minifyJshrink',
            ],
            5 => [
                $this,
                'minifyJsqueeze',
            ],
        ];
        return $functions[$minifier];
    }
    
    /**
     * Processes the contents of a javascript asset for cleanup.
     *
     * @param string $contents
     *   The contents of the javascript asset.
     * @param array $asset
     *   The core asset definition array.
     *
     * @return string
     *   Contents of the javascript asset.
     */
    public function clean($contents, array $asset) {
        if ($encoding = Unicode::encodingFromBOM($contents)) {
            $contents = mb_substr(Unicode::convertToUtf8($contents, $encoding), 1);
        }
        elseif (isset($asset['attributes']['charset'])) {
            $contents = Unicode::convertToUtf8($contents, $asset['attributes']['charset']);
        }
        // Remove JS source and source mapping urls or these may cause 404 errors.
        $contents = preg_replace('/\\/\\/(#|@)\\s(sourceURL|sourceMappingURL)=\\s*(\\S*?)\\s*$/m', '', $contents);
        return $contents;
    }
    
    /**
     * Minify a JS string using jsmin.
     *
     * @param string $contents
     *   JavaScript string.
     * @param string $path
     *   The original file path.
     */
    public function minifyJsmin(&$contents, $path) {
        // Do not use jsmin() if the function can not be called.
        if (!function_exists('jsmin')) {
            $this->logger
                ->notice($this->t('The jsmin function does not exist. Using JSqueeze.'), []);
            $contents = $this->minifyJsqueeze($contents);
            return;
        }
        // Jsmin doesn't handle multi-byte characters before version 2, fall back to
        // different minifier if jsmin version < 2 and $contents contains multi-
        // byte characters.
        if (version_compare(phpversion('jsmin'), '2.0.0', '<') && $this->stringContainsMultibyteCharacters($contents)) {
            $this->logger
                ->notice('The currently installed jsmin version does not handle multibyte characters, you may consider to upgrade the jsmin extension. Using JSqueeze fallback.', []);
            $contents = $this->minifyJsqueeze($contents);
            return;
        }
        // Jsmin may have errors (incorrectly determining EOLs) with mixed tabs
        // and spaces. An example: jQuery.Cycle 3.0.3 - http://jquery.malsup.com/
        $contents = str_replace("\t", " ", $contents);
        $minified = jsmin($contents);
        // Check for JSMin errors.
        $error = jsmin_last_error_msg();
        if ($error != 'No error') {
            $this->logger
                ->warning('JSMin had an error processing, using JSqueeze fallback. Error details: ' . $error, []);
            $contents = $this->minifyJsqueeze($contents);
            return;
        }
        // Under some unknown/rare circumstances, JSMin can add up to 5
        // extraneous/wrong chars at the end of the string. Check and remove if
        // necessary. The chars unfortunately vary in number and specific chars.
        // Hence this is a poor quality check but often works.
        if (ctype_cntrl(substr(trim($minified), -1)) || strpbrk(substr(trim($minified), -1), ';})') === FALSE) {
            $this->logger
                ->notice($this->t('JSMin had a possible error minifying: @file, correcting.', [
                '@file' => $path,
            ]));
            if (strrpos(substr($minified, -10), ';')) {
                $contents = substr($minified, 0, strrpos($minified, ';'));
            }
        }
        else {
            $contents = $minified;
        }
        $semicolons = substr_count($contents, ';', strlen($contents) - 5);
        if ($semicolons > 2) {
            $start = substr($contents, 0, -5);
            $contents = $start . preg_replace("/([;)}]*)([\\w]*)([;)}]*)/", "\$1\$3", substr($contents, -5));
            $this->logger
                ->notice($this->t('JSMin had an error minifying file: @file, attempting to correct.', [
                '@file' => $path,
            ]));
        }
    }
    
    /**
     * Minify a JS string using jsmin+.
     *
     * @param string $contents
     *   Javascript string.
     */
    public function minifyJsminplus(&$contents) {
        $contents_before = $contents;
        // Only include jsminplus.inc if the JSMinPlus class doesn't exist.
        if (!class_exists('\\JSMinPlus')) {
            include drupal_get_path('module', 'advagg_js_minify') . '/jsminplus.inc';
            $nesting_level = ini_get('xdebug.max_nesting_level');
            if (!empty($nesting_level) && $nesting_level < 200) {
                ini_set('xdebug.max_nesting_level', 200);
            }
        }
        ob_start();
        try {
            // JSMin+ the contents of the aggregated file.
            $contents = \JSMinPlus::minify($contents);
            // Capture any output from JSMinPlus.
            $error = trim(ob_get_contents());
            if (!empty($error)) {
                throw new \Exception($error);
            }
        } catch (\Exception $e) {
            // Log exception thrown by JSMin+ and roll back to uncompressed content.
            $this->logger
                ->warning($e->getMessage(), []);
            $contents = $contents_before;
        }
        ob_end_clean();
    }
    
    /**
     * Minify a JS string using packer.
     *
     * @param string $contents
     *   Javascript string.
     */
    public function minifyJspacker(&$contents) {
        // Use Packer on the contents of the aggregated file.
        if (!class_exists('\\JavaScriptPacker')) {
            include drupal_get_path('module', 'advagg_js_minify') . '/jspacker.inc';
        }
        // Add semicolons to the end of lines if missing.
        $contents = str_replace("}\n", "};\n", $contents);
        $contents = str_replace("\nfunction", ";\nfunction", $contents);
        $packer = new \JavaScriptPacker($contents, 62, TRUE, FALSE);
        $contents = $packer->pack();
    }
    
    /**
     * Minify a JS string using jshrink.
     *
     * @param string $contents
     *   Javascript string.
     */
    public function minifyJshrink(&$contents) {
        $contents_before = $contents;
        // Only include jshrink.inc if the JShrink\Minifier class doesn't exist.
        if (!class_exists('\\JShrink\\Minifier')) {
            include drupal_get_path('module', 'advagg_js_minify') . '/jshrink.inc';
            $nesting_level = ini_get('xdebug.max_nesting_level');
            if (!empty($nesting_level) && $nesting_level < 200) {
                ini_set('xdebug.max_nesting_level', 200);
            }
        }
        ob_start();
        try {
            // JShrink the contents of the aggregated file.
            // @codingStandardsIgnoreLine
            $contents = \JShrink\Minifier::minify($contents, [
                'flaggedComments' => FALSE,
            ]);
            // Capture any output from JShrink.
            $error = trim(ob_get_contents());
            if (!empty($error)) {
                throw new \Exception($error);
            }
        } catch (\Exception $e) {
            // Log the JShrink exception and rollback to uncompressed content.
            $this->logger
                ->warning($e->getMessage(), []);
            $contents = $contents_before;
        }
        ob_end_clean();
    }
    
    /**
     * Minify a JS string using jsqueeze.
     *
     * @param string $contents
     *   Javascript string.
     */
    public function minifyJsqueeze(&$contents) {
        $contents_before = $contents;
        // Only include jshrink.inc if the Patchwork\JSqueeze class doesn't exist.
        if (!class_exists('\\Patchwork\\JSqueeze')) {
            include drupal_get_path('module', 'advagg_js_minify') . '/jsqueeze.inc';
            $nesting_level = ini_get('xdebug.max_nesting_level');
            if (!empty($nesting_level) && $nesting_level < 200) {
                ini_set('xdebug.max_nesting_level', 200);
            }
        }
        ob_start();
        try {
            // Minify the contents of the aggregated file.
            // @codingStandardsIgnoreLine
            $jz = new \Patchwork\JSqueeze();
            $contents = $jz->squeeze($contents, TRUE, $this->config
                ->get('add_license'), FALSE);
            // Capture any output from JSqueeze.
            $error = trim(ob_get_contents());
            if (!empty($error)) {
                throw new \Exception($error);
            }
        } catch (\Exception $e) {
            // Log the JSqueeze exception and rollback to uncompressed content.
            $this->logger
                ->warning('JSqueeze error, skipping file. ' . $e->getMessage(), []);
            $contents = $contents_before;
        }
        ob_end_clean();
    }

}