diff core/lib/Drupal/Core/Asset/CssOptimizer.php @ 0:4c8ae668cc8c

Initial import (non-working)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/core/lib/Drupal/Core/Asset/CssOptimizer.php	Wed Nov 29 16:09:58 2017 +0000
@@ -0,0 +1,263 @@
+<?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)) . ')';
+  }
+
+}