Merge "Add a PromisePrioritizer and use it for notifications fetching"

Resources.php

@@ -196,6 +196,7 @@ $wgResourceModules += array(
 	'ext.echo.api' => $echoResourceTemplate + array(
 		'scripts' => array(
 			'api/mw.echo.api.js',
+			'api/mw.echo.api.PromisePrioritizer.js',
 			'api/mw.echo.api.EchoApi.js',
 			'api/mw.echo.api.APIHandler.js',
 			'api/mw.echo.api.LocalAPIHandler.js',

modules/api/mw.echo.api.EchoApi.js

@@ -15,6 +15,7 @@
 
 		this.fetchingPromise = null;
 		this.limit = config.limit || 25;
+		this.fetchingPrioritizer = new mw.echo.api.PromisePrioritizer();
 	};
 
 	OO.initClass( mw.echo.api.EchoApi );
@@ -147,13 +148,13 @@
 			return $.Deferred().reject().promise();
 		}
 
-		return handler.fetchNotifications(
+		return this.fetchingPrioritizer.prioritize( handler.fetchNotifications(
 			type,
 			// For the remote source, we are fetching 'local' notifications
 			'local',
 			!!isForced,
 			this.convertFiltersToAPIParams( filters )
-		)
+		) )
 			.then( function ( result ) {
 				return OO.getProp( result.query, 'notifications' );
 			} );
@@ -177,12 +178,12 @@
 				[ sources ] :
 				'local';
 
-		return this.network.getApiHandler( 'local' ).fetchNotifications(
+		return this.fetchingPrioritizer.prioritize( this.network.getApiHandler( 'local' ).fetchNotifications(
 			type,
 			sources,
 			isForced,
 			this.convertFiltersToAPIParams( filters )
-		)
+		) )
 			.then( function ( result ) {
 				return OO.getProp( result.query, 'notifications' );
 			} );

modules/api/mw.echo.api.PromisePrioritizer.js

@@ -0,0 +1,88 @@
+( function ( mw, $ ) {
+	/**
+	 * Promise prioritizer for API actions. The prioritizer takes
+	 * a promise at a time, always prioritizing the latest promise and
+	 * aborting and ignoring the others.
+	 *
+	 * This allows us to send multiple promises in quick successions but
+	 * trust that we get back only the latest successful request.
+	 *
+	 * @class
+	 *
+	 * @constructor
+	 */
+	mw.echo.api.PromisePrioritizer = function MwEchoApiPromisePrioritizer() {
+		this.deferred = $.Deferred();
+		this.promise = null;
+	};
+
+	/* Initialization */
+
+	OO.initClass( mw.echo.api.PromisePrioritizer );
+
+	/**
+	 * Prioritize a promise
+	 *
+	 * @param {jQuery.Promise|Promise} promise Promise
+	 * @return {jQuery.Promise} The main deferred object that resolves
+	 *  or rejects when the latest promise is resolved or rejected.
+	 */
+	mw.echo.api.PromisePrioritizer.prototype.prioritize = function ( promise ) {
+		var previousPromise = this.promise;
+
+		promise
+			.then(
+				this.setSuccess.bind( this, promise ),
+				this.setFailure.bind( this, promise )
+			);
+		this.promise = promise;
+
+		if ( previousPromise && previousPromise.abort ) {
+			previousPromise.abort();
+		}
+
+		return this.deferred.promise();
+	};
+
+	/**
+	 * Set success for the promise. Resolve the main deferred object only
+	 * if we are dealing with the currently prioritized promise.
+	 *
+	 * @param {jQuery.Promise} promise The promise that resolved successfully.
+	 *  The main deferred object is resolved with the result of the
+	 *  latest prioritized promise.
+	 */
+	mw.echo.api.PromisePrioritizer.prototype.setSuccess = function ( promise ) {
+		var prioritizer = this;
+
+		if ( this.promise === promise ) {
+			this.promise.done( function () {
+				prioritizer.deferred.resolve.apply( prioritizer.deferred, arguments );
+
+				prioritizer.promise = null;
+				prioritizer.deferred = $.Deferred();
+			} );
+		}
+	};
+
+	/**
+	 * Set failure for the promise. Reject the main deferred object only
+	 * if we are dealing with the currently prioritized promise.
+	 *
+	 * @param {jQuery.Promise} promise The promise that failed.
+	 *  The main deferred object is rejected with the result of the
+	 *  latest prioritized promise
+	 */
+	mw.echo.api.PromisePrioritizer.prototype.setFailure = function ( promise ) {
+		var prioritizer = this;
+
+		if ( this.promise === promise ) {
+			this.promise.fail( function () {
+				prioritizer.deferred.reject.apply( prioritizer.deferred, arguments );
+
+				prioritizer.promise = null;
+				prioritizer.deferred = $.Deferred();
+			} );
+		}
+	};
+} )( mediaWiki, jQuery );

modules/ui/mw.echo.ui.NotificationsInboxWidget.js

@@ -205,7 +205,6 @@
 	 */
 	mw.echo.ui.NotificationsInboxWidget.prototype.pushPending = function () {
 		this.noticeMessageWidget.toggle( false );
-		this.readStateSelectWidget.setDisabled( true );
 		this.topPaginationWidget.setDisabled( true );
 		this.bottomPaginationWidget.setDisabled( true );
 
@@ -218,7 +217,6 @@
 	 */
 	mw.echo.ui.NotificationsInboxWidget.prototype.popPending = function () {
 		this.resetMessageLabel();
-		this.readStateSelectWidget.setDisabled( false );
 		this.topPaginationWidget.setDisabled( false );
 		this.bottomPaginationWidget.setDisabled( false );