From 0afecbaf07e6b540f3c09ffa83ddd9030ba3ec07 Mon Sep 17 00:00:00 2001
From: Ori Livneh <ori@wikimedia.org>
Date: Mon, 7 Oct 2013 23:08:54 -0700
Subject: [PATCH] Add mediawiki.inspect module

This patch adds a mediawiki.inspect ResourceLoader module. The module contains
tools for inspecting page composition and performance. It is currently
restricted to a set of static methods for querying the ResourceLoader module
registry, the most useful of which is #inspectLoadedModules, which prints a
list of loaded ResourceLoader modules and their size in kilobytes, ordered from
largest to smallest. This method has a lazy-loading alias: mw.loader.inspect.

Change-Id: I5a007fdf11196664f425cd7800eec7fc3fdb629f
---
 maintenance/jsduck/categories.json       |   1 +
 maintenance/jsduck/config.json           |   1 +
 resources/Resources.php                  |   4 +
 resources/mediawiki/mediawiki.inspect.js | 102 +++++++++++++++++++++++
 resources/mediawiki/mediawiki.js         |  11 +++
 5 files changed, 119 insertions(+)
 create mode 100644 resources/mediawiki/mediawiki.inspect.js

diff --git a/maintenance/jsduck/categories.json b/maintenance/jsduck/categories.json
index 962b0820c8..e98e9c0fbe 100644
--- a/maintenance/jsduck/categories.json
+++ b/maintenance/jsduck/categories.json
@@ -20,6 +20,7 @@
 				"name": "General",
 				"classes": [
 					"mw.Title",
+					"mw.inspect",
 					"mw.notification",
 					"mw.user",
 					"mw.util",
diff --git a/maintenance/jsduck/config.json b/maintenance/jsduck/config.json
index 5cce68d962..12458eeb00 100644
--- a/maintenance/jsduck/config.json
+++ b/maintenance/jsduck/config.json
@@ -13,6 +13,7 @@
 		"../../resources/mediawiki/mediawiki.log.js",
 		"../../resources/mediawiki/mediawiki.util.js",
 		"../../resources/mediawiki/mediawiki.Title.js",
+		"../../resources/mediawiki/mediawiki.inspect.js",
 		"../../resources/mediawiki/mediawiki.notify.js",
 		"../../resources/mediawiki/mediawiki.notification.js",
 		"../../resources/mediawiki/mediawiki.user.js",
diff --git a/resources/Resources.php b/resources/Resources.php
index 880726b214..050e933f1b 100644
--- a/resources/Resources.php
+++ b/resources/Resources.php
@@ -646,6 +646,10 @@ return array(
 		// must be loaded on the bottom
 		'position' => 'bottom',
 	),
+	'mediawiki.inspect' => array(
+		'scripts' => 'resources/mediawiki/mediawiki.inspect.js',
+		'dependencies' => 'jquery.byteLength',
+	),
 	'mediawiki.feedback' => array(
 		'scripts' => 'resources/mediawiki/mediawiki.feedback.js',
 		'styles' => 'resources/mediawiki/mediawiki.feedback.css',
diff --git a/resources/mediawiki/mediawiki.inspect.js b/resources/mediawiki/mediawiki.inspect.js
new file mode 100644
index 0000000000..c4766ffb4d
--- /dev/null
+++ b/resources/mediawiki/mediawiki.inspect.js
@@ -0,0 +1,102 @@
+/*!
+ * Tools for inspecting page composition and performance.
+ *
+ * @author Ori Livneh
+ * @since 1.22
+ */
+( function ( mw, $ ) {
+
+	/**
+	 * @class mw.inspect
+	 * @singleton
+	 */
+	var inspect = {
+
+		/**
+		 * Calculate the byte size of a ResourceLoader module.
+		 *
+		 * @param {string} moduleName The name of the module
+		 * @return {number|null} Module size in bytes or null
+		 */
+		getModuleSize: function ( moduleName ) {
+			var module = mw.loader.moduleRegistry[ moduleName ],
+				payload = 0;
+
+			if ( mw.loader.getState( moduleName ) !== 'ready' ) {
+				return null;
+			}
+
+			if ( !module.style && !module.script ) {
+				return null;
+			}
+
+			// Tally CSS
+			if ( module.style && $.isArray( module.style.css ) ) {
+				$.each( module.style.css, function ( i, stylesheet ) {
+					payload += $.byteLength( stylesheet );
+				} );
+			}
+
+			// Tally JavaScript
+			if ( $.isFunction( module.script ) ) {
+				payload += $.byteLength( module.script.toString() );
+			}
+
+			return payload;
+		},
+
+		/**
+		 * Get a list of all loaded ResourceLoader modules.
+		 *
+		 * @return {Array} List of module names
+		 */
+		getLoadedModules: function () {
+			return $.grep( mw.loader.getModuleNames(), function ( module ) {
+				return mw.loader.getState( module ) === 'ready';
+			} );
+		},
+
+		/**
+		 * Print a breakdown of all loaded modules and their size in kilobytes
+		 * to the debug console. Modules are ordered from largest to smallest.
+		 */
+		inspectModules: function () {
+			var console = window.console;
+
+			$( function () {
+				// Map each module to a descriptor object.
+				var modules = $.map( inspect.getLoadedModules(), function ( module ) {
+					return {
+						name: module,
+						size: inspect.getModuleSize( module )
+					};
+				} );
+
+				// Sort module descriptors by size, largest first.
+				modules.sort( function ( a, b ) {
+					return b.size - a.size;
+				} );
+
+				// Convert size to human-readable string.
+				$.each( modules, function ( i, module ) {
+					module.size = module.size > 1024 ?
+						( module.size / 1024 ).toFixed( 2 ) + ' KB' :
+						( module.size !== null ? module.size + ' B' : null );
+				} );
+
+				if ( console ) {
+					if ( console.table ) {
+						console.table( modules );
+					} else {
+						$.each( modules, function ( i, module ) {
+							console.log( [ module.name, module.size ].join( '\t' ) );
+						} );
+					}
+				}
+			} );
+		}
+	};
+
+	mw.inspect = inspect;
+
+}( mediaWiki, jQuery ) );
diff --git a/resources/mediawiki/mediawiki.js b/resources/mediawiki/mediawiki.js
index 39093e3e6a..4138ac8d97 100644
--- a/resources/mediawiki/mediawiki.js
+++ b/resources/mediawiki/mediawiki.js
@@ -1699,7 +1699,18 @@ var mw = ( function ( $, undefined ) {
 				 */
 				go: function () {
 					mw.loader.load( 'mediawiki.user' );
+				},
+
+				/**
+				 * @inheritdoc mw.inspect#inspectModules
+				 * @method
+				 */
+				inspect: function () {
+					mw.loader.using( 'mediawiki.inspect', function () {
+						mw.inspect.inspectModules();
+					} );
 				}
+
 			};
 		}() ),
 
-- 
2.20.1