From a4631b92e7d57141954a2373ba33edae1512cb08 Mon Sep 17 00:00:00 2001
From: Roan Kattouw <roan.kattouw@gmail.com>
Date: Wed, 13 Sep 2017 11:56:46 -0700
Subject: [PATCH] Improve encoding of embedded SVGs

Unencode spaces, slashes, colons and equals signs.

Bug: T175318
Change-Id: Idebdfca8f93d5e090deba5bf5a256d7054e2d6c8
---
 includes/libs/CSSMin.php                   | 10 +++++++++-
 maintenance/benchmarks/cssmin/circle.svg   |  2 +-
 tests/phpunit/data/cssmin/circle.svg       |  2 +-
 tests/phpunit/includes/libs/CSSMinTest.php |  8 ++++----
 4 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/includes/libs/CSSMin.php b/includes/libs/CSSMin.php
index cd80066558..ee88d0d2b5 100644
--- a/includes/libs/CSSMin.php
+++ b/includes/libs/CSSMin.php
@@ -142,7 +142,15 @@ class CSSMin {
 		if ( preg_match( '/^[\r\n\t\x20-\x7e]+$/', $contents ) ) {
 			// Do not base64-encode non-binary files (sane SVGs).
 			// (This often produces longer URLs, but they compress better, yielding a net smaller size.)
-			$uri = 'data:' . $type . ',' . rawurlencode( $contents );
+			$encoded = rawurlencode( $contents );
+			// Unencode some things that don't need to be encoded, to make the encoding smaller
+			$encoded = strtr( $encoded, [
+				'%20' => ' ', // Unencode spaces
+				'%2F' => '/', // Unencode slashes
+				'%3A' => ':', // Unencode colons
+				'%3D' => '=', // Unencode equals signs
+			] );
+			$uri = 'data:' . $type . ',' . $encoded;
 			if ( !$ie8Compat || strlen( $uri ) < self::DATA_URI_SIZE_LIMIT ) {
 				return $uri;
 			}
diff --git a/maintenance/benchmarks/cssmin/circle.svg b/maintenance/benchmarks/cssmin/circle.svg
index 6b7d1afd87..4f7af21799 100644
--- a/maintenance/benchmarks/cssmin/circle.svg
+++ b/maintenance/benchmarks/cssmin/circle.svg
@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <svg xmlns="http://www.w3.org/2000/svg" width="8" height="8">
-<circle cx="4" cy="4" r="2"/>
+	<circle cx="4" cy="4" r="2"/>
 </svg>
diff --git a/tests/phpunit/data/cssmin/circle.svg b/tests/phpunit/data/cssmin/circle.svg
index 6b7d1afd87..4f7af21799 100644
--- a/tests/phpunit/data/cssmin/circle.svg
+++ b/tests/phpunit/data/cssmin/circle.svg
@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <svg xmlns="http://www.w3.org/2000/svg" width="8" height="8">
-<circle cx="4" cy="4" r="2"/>
+	<circle cx="4" cy="4" r="2"/>
 </svg>
diff --git a/tests/phpunit/includes/libs/CSSMinTest.php b/tests/phpunit/includes/libs/CSSMinTest.php
index 7d9a420c73..b06df97666 100644
--- a/tests/phpunit/includes/libs/CSSMinTest.php
+++ b/tests/phpunit/includes/libs/CSSMinTest.php
@@ -271,9 +271,9 @@ class CSSMinTest extends MediaWikiTestCase {
 		// data: URIs for red.gif, green.gif, circle.svg
 		$red   = 'data:image/gif;base64,R0lGODlhAQABAIAAAP8AADAAACwAAAAAAQABAAACAkQBADs=';
 		$green = 'data:image/gif;base64,R0lGODlhAQABAIAAAACAADAAACwAAAAAAQABAAACAkQBADs=';
-		$svg = 'data:image/svg+xml,%3C%3Fxml%20version%3D%221.0%22%20encoding%3D%22UTF-8%22%3F%3E%0A'
-			. '%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%228%22%20height%3D'
-			. '%228%22%3E%0A%3Ccircle%20cx%3D%224%22%20cy%3D%224%22%20r%3D%222%22%2F%3E%0A%3C%2Fsvg%3E%0A';
+		$svg = 'data:image/svg+xml,%3C%3Fxml version=%221.0%22 encoding=%22UTF-8%22%3F%3E%0A'
+			. '%3Csvg xmlns=%22http://www.w3.org/2000/svg%22 width=%228%22 height='
+			. '%228%22%3E%0A%09%3Ccircle cx=%224%22 cy=%224%22 r=%222%22/%3E%0A%3C/svg%3E%0A';
 
 		// @codingStandardsIgnoreStart Generic.Files.LineLength
 		return [
@@ -361,7 +361,7 @@ class CSSMinTest extends MediaWikiTestCase {
 			[
 				'SVG files are embedded without base64 encoding and unnecessary IE 6 and 7 fallback',
 				'foo { /* @embed */ background: url(circle.svg); }',
-				"foo { background: url($svg); }",
+				"foo { background: url(\"$svg\"); }",
 			],
 			[
 				'Two regular files in one rule',
-- 
2.20.1