CSSMin: factor out image encoding into encodeImageAsDataURI method

The code for encoding suitable images as base64 data URIs was previously part
of the remap method of CSSMin, which greps CSS files for /* @embed */
annotations. This patch moves it into its own method, encodeImageAsDataURI.

Change-Id: I6f57116c6a6c18ff9d4e28760dd484ea2c8fc493

diff --git a/includes/libs/CSSMin.php b/includes/libs/CSSMin.php
index 17e1258..4f142fc 100644 (file)
--- a/includes/libs/CSSMin.php
+++ b/includes/libs/CSSMin.php
@@ -81,6 +81,34 @@ class CSSMin {
                return $files;
        }
 
+       /**
+        * Encode an image file as a base64 data URI.
+        * If the image file has a suitable MIME type and size, encode it as a
+        * base64 data URI. Return false if the image type is unfamiliar or exceeds
+        * the size limit.
+        *
+        * @param string $file Image file to encode.
+        * @param string|null $type File's MIME type or null. If null, CSSMin will
+        *     try to autodetect the type.
+        * @param int|bool $sizeLimit If the size of the target file is greater than
+        *     this value, decline to encode the image file and return false
+        *     instead. If $sizeLimit is false, no limit is enforced.
+        * @return string|bool: Image contents encoded as a data URI or false.
+        */
+       public static function encodeImageAsDataURI( $file, $type = null, $sizeLimit = self::EMBED_SIZE_LIMIT ) {
+               if ( $sizeLimit !== false && filesize( $file ) >= $sizeLimit ) {
+                       return false;
+               }
+               if ( $type === null ) {
+                       $type = self::getMimeType( $file );
+               }
+               if ( !$type ) {
+                       return false;
+               }
+               $data = base64_encode( file_get_contents( $file ) );
+               return 'data:' . $type . ';base64,' . $data;
+       }
+
        /**
         * @param $file string
         * @return bool|string
@@ -174,23 +202,14 @@ class CSSMin {
                                // using Z for the timezone, meaning GMT
                                $url .= '?' . gmdate( 'Y-m-d\TH:i:s\Z', round( filemtime( $file ), -2 ) );
                                // Embedding requires a bit of extra processing, so let's skip that if we can
-                               if ( $embedData && $embed ) {
-                                       $type = self::getMimeType( $file );
-                                       // Detect when URLs were preceeded with embed tags, and also verify file size is
-                                       // below the limit
-                                       if (
-                                               $type
-                                               && $match['embed'][1] > 0
-                                               && filesize( $file ) < self::EMBED_SIZE_LIMIT
-                                       ) {
-                                               // Strip off any trailing = symbols (makes browsers freak out)
-                                               $data = base64_encode( file_get_contents( $file ) );
+                               if ( $embedData && $embed && $match['embed'][1] > 0 ) {
+                                       $data = self::encodeImageAsDataURI( $file );
+                                       if ( $data !== false ) {
                                                // Build 2 CSS properties; one which uses a base64 encoded data URI in place
                                                // of the @embed comment to try and retain line-number integrity, and the
                                                // other with a remapped an versioned URL and an Internet Explorer hack
                                                // making it ignored in all browsers that support data URIs
-                                               $replacement = "{$pre}url(data:{$type};base64,{$data}){$post};";
-                                               $replacement .= "{$pre}url({$url}){$post}!ie;";
+                                               $replacement = "{$pre}url({$data}){$post};{$pre}url({$url}){$post}!ie;";
                                        }
                                }
                                if ( $replacement === false ) {