Fix CSS cache handling and CSS output

This fixes several problems:
- the CSS cache was only updated when either the CSS files for all media
  types or one of the global files was modified
- when only the screen CSS was changed, the screen CSS was regenerated
  but then the cache was printed which either caused duplicated screen
  CSS output when gzip output was disabled or invalid output with gzip
  enabled as first the plain text screen CSS and then the
  gzip-compressed cache file was printed

Now first all CSS files are collected, then the cache is checked once
and only after this the CSS content is collected.

lib/exe/css.php

@@ -64,21 +64,27 @@ function css_out(){
     // start output buffering
     ob_start();
 
+    // Array of needed files and their web locations, the latter ones
+    // are needed to fix relative paths in the stylesheets
+    $files = array();
+
+    $cache_files = getConfigFiles('main');
+    $cache_files[] = $tplinc.'style.ini';
+    $cache_files[] = __FILE__;
+
     foreach($mediatypes as $mediatype) {
-        // Array of needed files and their web locations, the latter ones
-        // are needed to fix relative paths in the stylesheets
-        $files   = array();
+        $files[$mediatype] = array();
         // load core styles
-        $files[DOKU_INC.'lib/styles/'.$mediatype.'.css'] = DOKU_BASE.'lib/styles/';
+        $files[$mediatype][DOKU_INC.'lib/styles/'.$mediatype.'.css'] = DOKU_BASE.'lib/styles/';
         // load jQuery-UI theme
         if ($mediatype == 'screen') {
-            $files[DOKU_INC.'lib/scripts/jquery/jquery-ui-theme/smoothness.css'] = DOKU_BASE.'lib/scripts/jquery/jquery-ui-theme/';
+            $files[$mediatype][DOKU_INC.'lib/scripts/jquery/jquery-ui-theme/smoothness.css'] = DOKU_BASE.'lib/scripts/jquery/jquery-ui-theme/';
         }
         // load plugin styles
-        $files = array_merge($files, css_pluginstyles($mediatype));
+        $files[$mediatype] = array_merge($files[$mediatype], css_pluginstyles($mediatype));
         // load template styles
         if (isset($tplstyles[$mediatype])) {
-            $files = array_merge($files, $tplstyles[$mediatype]);
+            $files[$mediatype] = array_merge($files[$mediatype], $tplstyles[$mediatype]);
         }
         // if old 'default' userstyle setting exists, make it 'screen' userstyle for backwards compatibility
         if (isset($config_cascade['userstyle']['default'])) {
@@ -86,7 +92,7 @@ function css_out(){
         }
         // load user styles
         if(isset($config_cascade['userstyle'][$mediatype])){
-            $files[$config_cascade['userstyle'][$mediatype]] = DOKU_BASE;
+            $files[$mediatype][$config_cascade['userstyle'][$mediatype]] = DOKU_BASE;
         }
         // load rtl styles
         // note: this adds the rtl styles only to the 'screen' media type
@@ -94,20 +100,20 @@ function css_out(){
         //     please use "[dir=rtl]" in any css file in all, screen or print mode instead
         if ($mediatype=='screen') {
             if($lang['direction'] == 'rtl'){
-                if (isset($tplstyles['rtl'])) $files = array_merge($files, $tplstyles['rtl']);
+                if (isset($tplstyles['rtl'])) $files[$mediatype] = array_merge($files[$mediatype], $tplstyles['rtl']);
             }
         }
 
-        $cache_files = array_merge(array_keys($files), getConfigFiles('main'));
-        $cache_files[] = $tplinc.'style.ini';
-        $cache_files[] = __FILE__;
+        $cache_files = array_merge($cache_files, array_keys($files[$mediatype]));
+    }
 
-        // check cache age & handle conditional request
-        // This may exit if a cache can be used
-        http_cached($cache->cache,
-                    $cache->useCache(array('files' => $cache_files)));
+    // check cache age & handle conditional request
+    // This may exit if a cache can be used
+    http_cached($cache->cache,
+                $cache->useCache(array('files' => $cache_files)));
 
-        // build the stylesheet
+    // build the stylesheet
+    foreach ($mediatypes as $mediatype) {
 
         // print the default classes for interwiki links and file downloads
         if ($mediatype == 'screen') {
@@ -117,7 +123,7 @@ function css_out(){
 
         // load files
         $css_content = '';
-        foreach($files as $file => $location){
+        foreach($files[$mediatype] as $file => $location){
             $css_content .= css_loadfile($file, $location);
         }
         switch ($mediatype) {