Add provider to for actual image loading

Change-Id: I9ca9bce37c97648afa07db9f004138a791c74e65
Mingle: https://wikimedia.mingle.thoughtworks.com/projects/multimedia/cards/123

MultimediaViewer.php

@@ -150,6 +150,7 @@ call_user_func( function() {
 			'mmv.provider.ImageInfo.js',
 			'mmv.provider.FileRepoInfo.js',
 			'mmv.provider.ThumbnailInfo.js',
+			'mmv.provider.Image.js',
 		),
 
 		'dependencies' => array(

MultimediaViewerHooks.php

@@ -128,6 +128,7 @@ class MultimediaViewerHooks {
 				'tests/qunit/provider/mmv.provider.ImageInfo.test.js',
 				'tests/qunit/provider/mmv.provider.FileRepoInfo.test.js',
 				'tests/qunit/provider/mmv.provider.ThumbnailInfo.test.js',
+				'tests/qunit/provider/mmv.provider.Image.test.js',
 				'tests/qunit/mmv.lightboxinterface.test.js',
 				'tests/qunit/mmv.ui.description.test.js',
 				'tests/qunit/mmv.ui.fileUsage.test.js',

resources/mmv/provider/mmv.provider.Image.js

@@ -0,0 +1,49 @@
+/*
+ * This file is part of the MediaWiki extension MultimediaViewer.
+ *
+ * MultimediaViewer is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * MultimediaViewer is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with MultimediaViewer.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+( function ( mw, $ ) {
+
+	/**
+	 * @class mw.mmv.provider.Image
+	 * Loads an image.
+	 */
+	function Image() {
+	}
+
+	/**
+	 * @method
+	 * Loads an image and returns it.
+	 * @param {string} url
+	 * @return {jQuery.Promise<HTMLImageElement>} a promise which resolves to the image object
+	 */
+	Image.prototype.get = function( url ) {
+		var img = new window.Image(),
+			deferred = $.Deferred();
+
+		img.src = url;
+		img.onload = function() {
+			deferred.resolve( img );
+		};
+		img.onerror = function() {
+			deferred.reject( 'could not load image from ' + url );
+		};
+
+		return deferred.promise();
+	};
+
+	mw.mmv.provider.Image = Image;
+}( mediaWiki, jQuery ) );

tests/qunit/provider/mmv.provider.Image.test.js

@@ -0,0 +1,49 @@
+/*
+ * This file is part of the MediaWiki extension MultimediaViewer.
+ *
+ * MultimediaViewer is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * MultimediaViewer is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with MultimediaViewer.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+( function ( mw ) {
+	QUnit.module( 'mmv.provider.Image', QUnit.newMwEnvironment() );
+
+	QUnit.test( 'Image constructor sanity check', 1, function ( assert ) {
+		var imageProvider = new mw.mmv.provider.Image();
+
+		assert.ok( imageProvider );
+	} );
+
+	QUnit.asyncTest( 'Image load success test', 1, function ( assert ) {
+		var imageProvider = new mw.mmv.provider.Image();
+
+		imageProvider.get(
+			'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQAQMAAAAlPW0'
+			+ 'iAAAABlBMVEUAAAD///+l2Z/dAAAAM0lEQVR4nGP4/5/h/1+G/58ZDrAz3D/McH'
+			+ '8yw83NDDeNGe4Ug9C9zwz3gVLMDA/A6P9/AFGGFyjOXZtQAAAAAElFTkSuQmCC'
+		).then( function( image ) {
+				assert.ok( image instanceof HTMLImageElement,
+					'success handler was called with the image element');
+				QUnit.start();
+		} );
+	} );
+
+	QUnit.asyncTest( 'Image load fail test', 1, function ( assert ) {
+		var imageProvider = new mw.mmv.provider.Image();
+
+		imageProvider.get( 'doesntexist.png' ).fail( function() {
+				assert.ok( true, 'fail handler was called' );
+				QUnit.start();
+			} );
+	} );
+}( mediaWiki ) );