Issue #2220547 by nginex: Drupal 8 version

CHANGELOG.txt

+Conditional Styles 8.x-1.x, 2016-01-30
+------------------------------------------
+- #2220547 by nginex: Added Drupal 8 support
+
 Conditional Styles 7.x-2.2, 2013-07-12
 ------------------------------------------
 - #580440 by quicksketch: Add support for Downlevel-revealed Conditional Comments

README.txt

@@ -67,9 +67,12 @@ horribly-difficult-to-remember function calls to your theme's template.php file:
 Blech. Who wants to do that?
 
 This module allows you to add "conditional-stylesheets" in a much simpler
-manner, by adding lines to your theme's.info file. The syntax for that is:
+manner, by adding lines to your theme's.info.yml file. The syntax for that is:
 
-  stylesheets-conditional[EXPRESSION][MEDIA][] = stylesheet.css
+  conditional-stylesheets:
+    EXPRESSION:
+      MEDIA:
+        css/style.css
 
   where
     EXPRESSION can be any of the "downlevel-hidden" expressions specified in:
@@ -77,17 +80,24 @@ manner, by adding lines to your theme's.info file. The syntax for that is:
     MEDIA can be any of the normal CSS media keywords.
 
 For example, to add a stylesheet that only targets IE 6 and below, use:
-  stylesheets-conditional[lt IE 7][all][] = ie6-and-below.css
+  conditional-stylesheets:
+    lt IE 7:
+      all:
+        css/ie6-and-below.css
 
 To add a print stylesheet for IE9 only, use:
-  stylesheets-conditional[IE 9][print][] = ie9.css
+  conditional-stylesheets:
+    IE 9:
+      print:
+        css/ie9.css
 
 And to add a print stylesheet for all version of IE, use:
-  stylesheets-conditional[IE][print][] = ie.css
-
+  conditional-stylesheets:
+    IE:
+      print:
+        css/ie9.css
 
 *** IMPORTANT ***
 
-Drupal 7 stores a cache of the data in .info files. If you modify any lines in
-your theme's .info file, you MUST refresh Drupal 7's cache by simply visiting
-the Appearance page at admin/appearance.
+Drupal 8 stores a cache of the data in .info.yml files. If you modify any lines in
+your theme's .info.yml file, you MUST rebuild Drupal 8's cache.

conditional_styles.info.yml

 name: Conditional Stylesheets
 type: module
 description: 'Allows themes to add conditional stylesheets.'
-package: Other
-version: VERSION
 core: 8.x
+package: Other

conditional_styles.module

@@ -5,31 +5,33 @@
  * Adds conditional CSS from the .info file.
  */
 
+use \Drupal\Component\Utility\Unicode;
+
 /**
- * Implements hook_page_build().
+ * Implements hook_css_alter().
  */
-function conditional_styles_page_build(&$page) {
+function conditional_styles_css_alter(&$css, \Drupal\Core\Asset\AttachedAssetsInterface $assets) {
   $theme_handler = \Drupal::service('theme_handler');
-  $themes        = $theme_handler->listInfo(); 
-  foreach ($themes as $theme) {
-    $theme_path = drupal_get_path($theme->type, $theme->name);
-    if (isset($theme->info['stylesheets-conditional']) && $theme->status) {
-      foreach ($theme->info['stylesheets-conditional'] as $condition => $medias) {
-        foreach ($medias as $media => $stylesheets) {
-	        foreach ($stylesheets as $stylesheet) {
-	        	$full_path = $theme_path . '/' . $stylesheet;
-	          $page['#attached']['css'][$full_path] = array(
-          		'group' => CSS_THEME,
-          		'weight' => 999,
-          		'media' => $media,
-          		'every_page' => TRUE,
-              'browsers' => array(
-                'IE'  => $condition,
-                '!IE' => strpos($condition, '!IE') === FALSE ? FALSE : TRUE,
-              ),
-	          );
-	        }
-        }
+  $current_theme = $theme_handler->getDefault();
+  $path = drupal_get_path('theme', $current_theme);
+  $info = $theme_handler->getTheme($current_theme)->info;
+  if (!empty($info['conditional-stylesheets'])) {
+    foreach ($info['conditional-stylesheets'] as $version => $media) {
+      foreach ($media as $key => $file_path) {
+        $full_path = "{$path}/{$file_path}";
+        $css[$full_path] = [
+          'group' => CSS_THEME,
+          'weight' => 999,
+          'type' => 'file',
+          'preprocess' => TRUE,
+          'data' => $full_path,
+          'media' => $key,
+          'every_page' => TRUE,
+          'browsers' => [
+            'IE'  => $version,
+            '!IE' => (Unicode::strpos($version, '!IE') !== FALSE),
+          ],
+        ];
       }
     }
   }