From 6333fa6191ca5a2f5823ad4185a6e699e8674cfc Mon Sep 17 00:00:00 2001
From: Ori Livneh <ori@wikimedia.org>
Date: Fri, 3 Apr 2015 16:17:13 -0700
Subject: [PATCH] Html::srcSet: allow density to be specified either with or
 without trailing 'x'

$wgLogoHD is meant to contain high-density alternatives for $wgLogo, but its
keys include the trailing 'x' (e.g., '1.5x'), making it unusable with
Html::srcSet(). Fix that by normalizing all density values to have a
single trailing 'x'.

Change-Id: I62cc3a9e4aeff3a7cb102de2965b8b40fd106c37
---
 includes/Html.php                   | 26 ++++++++++++++++++++------
 tests/phpunit/includes/HtmlTest.php | 24 ++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/includes/Html.php b/includes/Html.php
index effc488091..d312e0a6e9 100644
--- a/includes/Html.php
+++ b/includes/Html.php
@@ -1025,9 +1025,24 @@ class Html {
 	}
 
 	/**
-	 * Generate a srcset attribute value from an array mapping pixel densities
-	 * to URLs. Note that srcset supports width and height values as well, which
-	 * are not used here.
+	 * Generate a srcset attribute value.
+	 *
+	 * Generates a srcset attribute value from an array mapping pixel densities
+	 * to URLs. A trailing 'x' in pixel density values is optional.
+	 *
+	 * @note srcset width and height values are not supported.
+	 *
+	 * @see http://www.whatwg.org/html/embedded-content-1.html#attr-img-srcset
+	 *
+	 * @par Example:
+	 * @code
+	 *     Html::srcSet( array(
+	 *         '1x'   => 'standard.jpeg',
+	 *         '1.5x' => 'large.jpeg',
+	 *         '3x'   => 'extra-large.jpeg',
+	 *     ) );
+	 *     // gives 'standard.jpeg 1x, large.jpeg 1.5x, extra-large.jpeg 2x'
+	 * @endcode
 	 *
 	 * @param string[] $urls
 	 * @return string
@@ -1035,9 +1050,8 @@ class Html {
 	static function srcSet( $urls ) {
 		$candidates = array();
 		foreach ( $urls as $density => $url ) {
-			// Image candidate syntax per current whatwg live spec, 2012-09-23:
-			// http://www.whatwg.org/html/embedded-content-1.html#attr-img-srcset
-			$candidates[] = "{$url} {$density}x";
+			// Cast density to float to strip 'x'.
+			$candidates[] = $url . ' ' . (float)$density . 'x';
 		}
 		return implode( ", ", $candidates );
 	}
diff --git a/tests/phpunit/includes/HtmlTest.php b/tests/phpunit/includes/HtmlTest.php
index 0b58536619..c5797c4f60 100644
--- a/tests/phpunit/includes/HtmlTest.php
+++ b/tests/phpunit/includes/HtmlTest.php
@@ -764,6 +764,30 @@ class HtmlTest extends MediaWikiTestCase {
 			'Label wrapper'
 		);
 	}
+
+	public static function provideSrcSetImages() {
+		return array(
+			array( array(), '', 'when there are no images, return empty string' ),
+			array(
+				array( '1x' => '1x.png', '1.5x' => '1_5x.png', '2x' => '2x.png' ),
+				'1x.png 1x, 1_5x.png 1.5x, 2x.png 2x',
+				'pixel depth keys may include a trailing "x"'
+			),
+			array(
+				array( '1'  => '1x.png', '1.5' => '1_5x.png', '2'  => '2x.png' ),
+				'1x.png 1x, 1_5x.png 1.5x, 2x.png 2x',
+				'pixel depth keys may omit a trailing "x"'
+			),
+		);
+	}
+
+	/**
+	 * @dataProvider provideSrcSetImages
+	 * @covers Html::srcSet
+	 */
+	public function testSrcSet( $images, $expected, $message ) {
+		$this->assertEquals( Html::srcSet( $images ), $expected, $message );
+	}
 }
 
 class HtmlTestValue {
-- 
2.20.1