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- <?php
- namespace Drupal\Core\Asset;
- use Drupal\Component\Utility\Unicode;
- /**
- * Optimizes a CSS asset.
- */
- class CssOptimizer implements AssetOptimizerInterface {
- /**
- * The base path used by rewriteFileURI().
- *
- * @var string
- */
- public $rewriteFileURIBasePath;
- /**
- * {@inheritdoc}
- */
- public function optimize(array $css_asset) {
- if ($css_asset['type'] != 'file') {
- throw new \Exception('Only file CSS assets can be optimized.');
- }
- if (!$css_asset['preprocess']) {
- throw new \Exception('Only file CSS assets with preprocessing enabled can be optimized.');
- }
- return $this->processFile($css_asset);
- }
- /**
- * Processes the contents of a CSS asset for cleanup.
- *
- * @param string $contents
- * The contents of the CSS asset.
- *
- * @return string
- * Contents of the CSS asset.
- */
- public function clean($contents) {
- // Remove multiple charset declarations for standards compliance (and fixing
- // Safari problems).
- $contents = preg_replace('/^@charset\s+[\'"](\S*?)\b[\'"];/i', '', $contents);
- return $contents;
- }
- /**
- * Build aggregate CSS file.
- */
- protected function processFile($css_asset) {
- $contents = $this->loadFile($css_asset['data'], TRUE);
- $contents = $this->clean($contents);
- // Get the parent directory of this file, relative to the Drupal root.
- $css_base_path = substr($css_asset['data'], 0, strrpos($css_asset['data'], '/'));
- // Store base path.
- $this->rewriteFileURIBasePath = $css_base_path . '/';
- // Anchor all paths in the CSS with its base URL, ignoring external and absolute paths.
- return preg_replace_callback('/url\(\s*[\'"]?(?![a-z]+:|\/+)([^\'")]+)[\'"]?\s*\)/i', [$this, 'rewriteFileURI'], $contents);
- }
- /**
- * Loads the stylesheet and resolves all @import commands.
- *
- * Loads a stylesheet and replaces @import commands with the contents of the
- * imported file. Use this instead of file_get_contents when processing
- * stylesheets.
- *
- * The returned contents are compressed removing white space and comments only
- * when CSS aggregation is enabled. This optimization will not apply for
- * color.module enabled themes with CSS aggregation turned off.
- *
- * Note: the only reason this method is public is so color.module can call it;
- * it is not on the AssetOptimizerInterface, so future refactorings can make
- * it protected.
- *
- * @param $file
- * Name of the stylesheet to be processed.
- * @param $optimize
- * Defines if CSS contents should be compressed or not.
- * @param $reset_basepath
- * Used internally to facilitate recursive resolution of @import commands.
- *
- * @return
- * Contents of the stylesheet, including any resolved @import commands.
- */
- public function loadFile($file, $optimize = NULL, $reset_basepath = TRUE) {
- // These statics are not cache variables, so we don't use drupal_static().
- static $_optimize, $basepath;
- if ($reset_basepath) {
- $basepath = '';
- }
- // Store the value of $optimize for preg_replace_callback with nested
- // @import loops.
- if (isset($optimize)) {
- $_optimize = $optimize;
- }
- // Stylesheets are relative one to each other. Start by adding a base path
- // prefix provided by the parent stylesheet (if necessary).
- if ($basepath && !file_uri_scheme($file)) {
- $file = $basepath . '/' . $file;
- }
- // Store the parent base path to restore it later.
- $parent_base_path = $basepath;
- // Set the current base path to process possible child imports.
- $basepath = dirname($file);
- // Load the CSS stylesheet. We suppress errors because themes may specify
- // stylesheets in their .info.yml file that don't exist in the theme's path,
- // but are merely there to disable certain module CSS files.
- $content = '';
- if ($contents = @file_get_contents($file)) {
- // If a BOM is found, convert the file to UTF-8, then use substr() to
- // remove the BOM from the result.
- if ($encoding = (Unicode::encodingFromBOM($contents))) {
- $contents = Unicode::substr(Unicode::convertToUtf8($contents, $encoding), 1);
- }
- // If no BOM, check for fallback encoding. Per CSS spec the regex is very strict.
- elseif (preg_match('/^@charset "([^"]+)";/', $contents, $matches)) {
- if ($matches[1] !== 'utf-8' && $matches[1] !== 'UTF-8') {
- $contents = substr($contents, strlen($matches[0]));
- $contents = Unicode::convertToUtf8($contents, $matches[1]);
- }
- }
- // Return the processed stylesheet.
- $content = $this->processCss($contents, $_optimize);
- }
- // Restore the parent base path as the file and its children are processed.
- $basepath = $parent_base_path;
- return $content;
- }
- /**
- * Loads stylesheets recursively and returns contents with corrected paths.
- *
- * This function is used for recursive loading of stylesheets and
- * returns the stylesheet content with all url() paths corrected.
- *
- * @param array $matches
- * An array of matches by a preg_replace_callback() call that scans for
- * @import-ed CSS files, except for external CSS files.
- *
- * @return
- * The contents of the CSS file at $matches[1], with corrected paths.
- *
- * @see \Drupal\Core\Asset\AssetOptimizerInterface::loadFile()
- */
- protected function loadNestedFile($matches) {
- $filename = $matches[1];
- // Load the imported stylesheet and replace @import commands in there as
- // well.
- $file = $this->loadFile($filename, NULL, FALSE);
- // Determine the file's directory.
- $directory = dirname($filename);
- // If the file is in the current directory, make sure '.' doesn't appear in
- // the url() path.
- $directory = $directory == '.' ? '' : $directory . '/';
- // Alter all internal url() paths. Leave external paths alone. We don't need
- // to normalize absolute paths here because that will be done later.
- return preg_replace('/url\(\s*([\'"]?)(?![a-z]+:|\/+)([^\'")]+)([\'"]?)\s*\)/i', 'url(\1' . $directory . '\2\3)', $file);
- }
- /**
- * Processes the contents of a stylesheet for aggregation.
- *
- * @param $contents
- * The contents of the stylesheet.
- * @param $optimize
- * (optional) Boolean whether CSS contents should be minified. Defaults to
- * FALSE.
- *
- * @return
- * Contents of the stylesheet including the imported stylesheets.
- */
- protected function processCss($contents, $optimize = FALSE) {
- // Remove unwanted CSS code that cause issues.
- $contents = $this->clean($contents);
- if ($optimize) {
- // Perform some safe CSS optimizations.
- // Regexp to match comment blocks.
- $comment = '/\*[^*]*\*+(?:[^/*][^*]*\*+)*/';
- // Regexp to match double quoted strings.
- $double_quot = '"[^"\\\\]*(?:\\\\.[^"\\\\]*)*"';
- // Regexp to match single quoted strings.
- $single_quot = "'[^'\\\\]*(?:\\\\.[^'\\\\]*)*'";
- // Strip all comment blocks, but keep double/single quoted strings.
- $contents = preg_replace(
- "<($double_quot|$single_quot)|$comment>Ss",
- "$1",
- $contents
- );
- // Remove certain whitespace.
- // There are different conditions for removing leading and trailing
- // whitespace.
- // @see http://php.net/manual/regexp.reference.subpatterns.php
- $contents = preg_replace('<
- # Do not strip any space from within single or double quotes
- (' . $double_quot . '|' . $single_quot . ')
- # Strip leading and trailing whitespace.
- | \s*([@{};,])\s*
- # Strip only leading whitespace from:
- # - Closing parenthesis: Retain "@media (bar) and foo".
- | \s+([\)])
- # Strip only trailing whitespace from:
- # - Opening parenthesis: Retain "@media (bar) and foo".
- # - Colon: Retain :pseudo-selectors.
- | ([\(:])\s+
- >xSs',
- // Only one of the four capturing groups will match, so its reference
- // will contain the wanted value and the references for the
- // two non-matching groups will be replaced with empty strings.
- '$1$2$3$4',
- $contents
- );
- // End the file with a new line.
- $contents = trim($contents);
- $contents .= "\n";
- }
- // Replaces @import commands with the actual stylesheet content.
- // This happens recursively but omits external files.
- $contents = preg_replace_callback('/@import\s*(?:url\(\s*)?[\'"]?(?![a-z]+:)(?!\/\/)([^\'"\()]+)[\'"]?\s*\)?\s*;/', [$this, 'loadNestedFile'], $contents);
- return $contents;
- }
- /**
- * Prefixes all paths within a CSS file for processFile().
- *
- * Note: the only reason this method is public is so color.module can call it;
- * it is not on the AssetOptimizerInterface, so future refactorings can make
- * it protected.
- *
- * @param array $matches
- * An array of matches by a preg_replace_callback() call that scans for
- * url() references in CSS files, except for external or absolute ones.
- *
- * @return string
- * The file path.
- */
- public function rewriteFileURI($matches) {
- // Prefix with base and remove '../' segments where possible.
- $path = $this->rewriteFileURIBasePath . $matches[1];
- $last = '';
- while ($path != $last) {
- $last = $path;
- $path = preg_replace('`(^|/)(?!\.\./)([^/]+)/\.\./`', '$1', $path);
- }
- return 'url(' . file_url_transform_relative(file_create_url($path)) . ')';
- }
- }
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