resources/src/startup/mediawiki.loader.js
/*!
* Defines mw.loader, the infrastructure for loading ResourceLoader
* modules.
*
* This file is appended directly to the code in startup/mediawiki.js
*/
/* global $VARS, $CODE, mw */
( function () {
'use strict';
var store,
hasOwn = Object.hasOwnProperty;
/**
* Client for ResourceLoader server end point.
*
* This client is in charge of maintaining the module registry and state
* machine, initiating network (batch) requests for loading modules, as
* well as dependency resolution and execution of source code.
*
* @see <https://www.mediawiki.org/wiki/ResourceLoader/Features>
* @namespace mw.loader
* @memberof mw
* @singleton
* @hideconstructor
* @static
*/
/**
* FNV132 hash function
*
* This function implements the 32-bit version of FNV-1.
* It is equivalent to hash( 'fnv132', ... ) in PHP, except
* its output is base 36 rather than hex.
* See <https://en.wikipedia.org/wiki/Fowler–Noll–Vo_hash_function>
*
* @private
* @param {string} str String to hash
* @return {string} hash as a five-character base 36 string
*/
function fnv132( str ) {
var hash = 0x811C9DC5;
/* eslint-disable no-bitwise */
for ( var i = 0; i < str.length; i++ ) {
hash += ( hash << 1 ) + ( hash << 4 ) + ( hash << 7 ) + ( hash << 8 ) + ( hash << 24 );
hash ^= str.charCodeAt( i );
}
hash = ( hash >>> 0 ).toString( 36 ).slice( 0, 5 );
/* eslint-enable no-bitwise */
while ( hash.length < 5 ) {
hash = '0' + hash;
}
return hash;
}
/**
* Fired via mw.track on various resource loading errors.
*
* eslint-disable jsdoc/valid-types
* @event ~'resourceloader.exception'
* @ignore
* @param {Error|Mixed} e The error that was thrown. Almost always an Error
* object, but in theory module code could manually throw something else, and that
* might also end up here.
* @param {string} [module] Name of the module which caused the error. Omitted if the
* error is not module-related or the module cannot be easily identified due to
* batched handling.
* @param {string} source Source of the error. Possible values:
*
* - load-callback: exception thrown by user callback
* - module-execute: exception thrown by module code
* - resolve: failed to sort dependencies for a module in mw.loader.load
* - store-eval: could not evaluate module code cached in localStorage
* - store-localstorage-json: JSON conversion error in mw.loader.store
* - store-localstorage-update: localStorage conversion error in mw.loader.store.
*/
/**
* Mapping of registered modules.
*
* See #implement and #execute for exact details on support for script, style and messages.
*
* @example // Format:
* {
* 'moduleName': {
* // From mw.loader.register()
* 'version': '#####' (five-character hash)
* 'dependencies': ['required.foo', 'bar.also', ...]
* 'group': string, integer, (or) null
* 'source': 'local', (or) 'anotherwiki'
* 'skip': 'return !!window.Example;', (or) null, (or) boolean result of skip
* 'module': export Object
*
* // Set by execute() or mw.loader.state()
* // See mw.loader.getState() for documentation of the state machine
* 'state': 'registered', 'loading', 'loaded', 'executing', 'ready', 'error', or 'missing'
*
* // Optionally added at run-time by mw.loader.impl()
* 'script': closure, array of urls, or string
* 'style': { ... } (see #execute)
* 'messages': { 'key': 'value', ... }
* }
* }
*
* @property {Object}
* @private
*/
var registry = Object.create( null ),
// Mapping of sources, keyed by source-id, values are strings.
//
// Format:
//
// {
// 'sourceId': 'http://example.org/w/load.php'
// }
//
sources = Object.create( null ),
// For queueModuleScript()
handlingPendingRequests = false,
pendingRequests = [],
// List of modules to be loaded
queue = [],
/**
* List of callback jobs waiting for modules to be ready.
*
* Jobs are created by #enqueue() and run by #doPropagation().
* Typically when a job is created for a module, the job's dependencies contain
* both the required module and all its recursive dependencies.
*
* @example // Format:
* {
* 'dependencies': [ module names ],
* 'ready': Function callback
* 'error': Function callback
* }
*
* @property {Object[]} jobs
* @private
*/
jobs = [],
// For #setAndPropagate() and #doPropagation()
willPropagate = false,
errorModules = [],
/**
* @private
* @property {Array} baseModules
*/
baseModules = $VARS.baseModules,
/**
* For #addEmbeddedCSS() and #addLink()
*
* @private
* @property {HTMLElement|null} marker
*/
marker = document.querySelector( 'meta[name="ResourceLoaderDynamicStyles"]' ),
// For #addEmbeddedCSS()
lastCssBuffer;
/**
* Append an HTML element to `document.head` or before a specified node.
*
* @private
* @param {HTMLElement} el
* @param {Node|null} [nextNode]
*/
function addToHead( el, nextNode ) {
if ( nextNode && nextNode.parentNode ) {
nextNode.parentNode.insertBefore( el, nextNode );
} else {
document.head.appendChild( el );
}
}
/**
* Create a new style element and add it to the DOM.
* Stable for use in gadgets.
*
* @method mw.loader.addStyleTag
* @param {string} text CSS text
* @param {Node|null} [nextNode] The element where the style tag
* should be inserted before
* @return {HTMLStyleElement} Reference to the created style element
*/
function newStyleTag( text, nextNode ) {
var el = document.createElement( 'style' );
el.appendChild( document.createTextNode( text ) );
addToHead( el, nextNode );
return el;
}
/**
* @private
* @param {Object} cssBuffer
*/
function flushCssBuffer( cssBuffer ) {
// Make sure the next call to addEmbeddedCSS() starts a new buffer.
// This must be done before we run the callbacks, as those may end up
// queueing new chunks which would be lost otherwise (T105973).
//
// There can be more than one buffer in-flight (given "@import", and
// generally due to race conditions). Only tell addEmbeddedCSS() to
// start a new buffer if we're currently flushing the last one that it
// started. If we're flushing an older buffer, keep the last one open.
if ( cssBuffer === lastCssBuffer ) {
lastCssBuffer = null;
}
newStyleTag( cssBuffer.cssText, marker );
for ( var i = 0; i < cssBuffer.callbacks.length; i++ ) {
cssBuffer.callbacks[ i ]();
}
}
/**
* Add a bit of CSS text to the current browser page.
*
* The creation and insertion of the `<style>` element is debounced for two reasons:
*
* - Performing the insertion before the next paint round via requestAnimationFrame
* avoids forced or wasted style recomputations, which are expensive in browsers.
* - Reduce how often new stylesheets are inserted by letting additional calls to this
* function accumulate into a buffer for at least one JavaScript tick. Modules are
* received from the server in batches, which means there is likely going to be many
* calls to this function in a row within the same tick / the same call stack.
* See also T47810.
*
* @private
* @param {string} cssText CSS text to be added in a `<style>` tag.
* @param {Function} callback Called after the insertion has occurred.
*/
function addEmbeddedCSS( cssText, callback ) {
// Start a new buffer if one of the following is true:
// - We've never started a buffer before, this will be our first.
// - The last buffer we created was flushed meanwhile, so start a new one.
// - The next CSS chunk syntactically needs to be at the start of a stylesheet (T37562).
if ( !lastCssBuffer || cssText.startsWith( '@import' ) ) {
lastCssBuffer = {
cssText: '',
callbacks: []
};
requestAnimationFrame( flushCssBuffer.bind( null, lastCssBuffer ) );
}
// Linebreak for somewhat distinguishable sections
lastCssBuffer.cssText += '\n' + cssText;
lastCssBuffer.callbacks.push( callback );
}
/**
* See also `ResourceLoader.php#makeVersionQuery` on the server.
*
* @private
* @param {string[]} modules List of module names
* @return {string} Hash of concatenated version hashes.
*/
function getCombinedVersion( modules ) {
var hashes = modules.reduce( function ( result, module ) {
return result + registry[ module ].version;
}, '' );
return fnv132( hashes );
}
/**
* Determine whether all dependencies are in state 'ready', which means we may
* execute the module or job now.
*
* @private
* @param {string[]} modules Names of modules to be checked
* @return {boolean} True if all modules are in state 'ready', false otherwise
*/
function allReady( modules ) {
for ( var i = 0; i < modules.length; i++ ) {
if ( mw.loader.getState( modules[ i ] ) !== 'ready' ) {
return false;
}
}
return true;
}
/**
* Determine whether all direct and base dependencies are in state 'ready'
*
* @private
* @param {string} module Name of the module to be checked
* @return {boolean} True if all direct/base dependencies are in state 'ready'; false otherwise
*/
function allWithImplicitReady( module ) {
return allReady( registry[ module ].dependencies ) &&
( baseModules.indexOf( module ) !== -1 || allReady( baseModules ) );
}
/**
* Determine whether all dependencies are in state 'ready', which means we may
* execute the module or job now.
*
* @private
* @param {string[]} modules Names of modules to be checked
* @return {boolean|string} False if no modules are in state 'error' or 'missing';
* failed module otherwise
*/
function anyFailed( modules ) {
for ( var i = 0; i < modules.length; i++ ) {
var state = mw.loader.getState( modules[ i ] );
if ( state === 'error' || state === 'missing' ) {
return modules[ i ];
}
}
return false;
}
/**
* Handle propagation of module state changes and reactions to them.
*
* - When a module reaches a failure state, this should be propagated to
* modules that depend on the failed module.
* - When a module reaches a final state, pending job callbacks for the
* module from mw.loader.using() should be called.
* - When a module reaches the 'ready' state from #execute(), consider
* executing dependent modules now having their dependencies satisfied.
* - When a module reaches the 'loaded' state from mw.loader.impl,
* consider executing it, if it has no unsatisfied dependencies.
*
* @private
*/
function doPropagation() {
var didPropagate = true;
var module;
// Keep going until the last iteration performed no actions.
while ( didPropagate ) {
didPropagate = false;
// Stage 1: Propagate failures
while ( errorModules.length ) {
var errorModule = errorModules.shift(),
baseModuleError = baseModules.indexOf( errorModule ) !== -1;
for ( module in registry ) {
if ( registry[ module ].state !== 'error' && registry[ module ].state !== 'missing' ) {
if ( baseModuleError && baseModules.indexOf( module ) === -1 ) {
// Propate error from base module to all regular (non-base) modules
registry[ module ].state = 'error';
didPropagate = true;
} else if ( registry[ module ].dependencies.indexOf( errorModule ) !== -1 ) {
// Propagate error from dependency to depending module
registry[ module ].state = 'error';
// .. and propagate it further
errorModules.push( module );
didPropagate = true;
}
}
}
}
// Stage 2: Execute 'loaded' modules with no unsatisfied dependencies
for ( module in registry ) {
if ( registry[ module ].state === 'loaded' && allWithImplicitReady( module ) ) {
// Recursively execute all dependent modules that were already loaded
// (waiting for execution) and no longer have unsatisfied dependencies.
// Base modules may have dependencies amongst eachother to ensure correct
// execution order. Regular modules wait for all base modules.
execute( module );
didPropagate = true;
}
}
// Stage 3: Invoke job callbacks that are no longer blocked
for ( var i = 0; i < jobs.length; i++ ) {
var job = jobs[ i ];
var failed = anyFailed( job.dependencies );
if ( failed !== false || allReady( job.dependencies ) ) {
jobs.splice( i, 1 );
i -= 1;
try {
if ( failed !== false && job.error ) {
job.error( new Error( 'Failed dependency: ' + failed ), job.dependencies );
} else if ( failed === false && job.ready ) {
job.ready();
}
} catch ( e ) {
// A user-defined callback raised an exception.
// Swallow it to protect our state machine!
mw.trackError( {
exception: e,
source: 'load-callback'
} );
}
didPropagate = true;
}
}
}
willPropagate = false;
}
/**
* Update a module's state in the registry and make sure any necessary
* propagation will occur, by adding a (debounced) call to doPropagation().
* See #doPropagation for more about propagation.
* See #registry for more about how states are used.
*
* @private
* @param {string} module
* @param {string} state
*/
function setAndPropagate( module, state ) {
registry[ module ].state = state;
if ( state === 'ready' ) {
// Queue to later be synced to the local module store.
store.add( module );
} else if ( state === 'error' || state === 'missing' ) {
errorModules.push( module );
} else if ( state !== 'loaded' ) {
// We only have something to do in doPropagation for the
// 'loaded', 'ready', 'error', and 'missing' states.
// Avoid scheduling and propagation cost for frequent and short-lived
// transition states, such as 'loading' and 'executing'.
return;
}
if ( willPropagate ) {
// Already scheduled, or, we're already in a doPropagation stack.
return;
}
willPropagate = true;
// Yield for two reasons:
// * Allow successive calls to mw.loader.impl() from the same
// load.php response, or from the same asyncEval() to be in the
// propagation batch.
// * Allow the browser to breathe between the reception of
// module source code and the execution of it.
//
// Use a high priority because the user may be waiting for interactions
// to start being possible. But, first provide a moment (up to 'timeout')
// for native input event handling (e.g. scrolling/typing/clicking).
mw.requestIdleCallback( doPropagation, { timeout: 1 } );
}
/**
* Resolve dependencies and detect circular references.
*
* @private
* @param {string} module Name of the top-level module whose dependencies shall be
* resolved and sorted.
* @param {Array} resolved Returns a topological sort of the given module and its
* dependencies, such that later modules depend on earlier modules. The array
* contains the module names. If the array contains already some module names,
* this function appends its result to the pre-existing array.
* @param {Set} [unresolved] Used to detect loops in the dependency graph.
* @throws {Error} If an unknown module or a circular dependency is encountered
*/
function sortDependencies( module, resolved, unresolved ) {
if ( !( module in registry ) ) {
throw new Error( 'Unknown module: ' + module );
}
if ( typeof registry[ module ].skip === 'string' ) {
// eslint-disable-next-line no-new-func
var skip = ( new Function( registry[ module ].skip )() );
registry[ module ].skip = !!skip;
if ( skip ) {
registry[ module ].dependencies = [];
setAndPropagate( module, 'ready' );
return;
}
}
// Create unresolved if not passed in
if ( !unresolved ) {
unresolved = new Set();
}
// Track down dependencies
var deps = registry[ module ].dependencies;
unresolved.add( module );
for ( var i = 0; i < deps.length; i++ ) {
if ( resolved.indexOf( deps[ i ] ) === -1 ) {
if ( unresolved.has( deps[ i ] ) ) {
throw new Error(
'Circular reference detected: ' + module + ' -> ' + deps[ i ]
);
}
sortDependencies( deps[ i ], resolved, unresolved );
}
}
resolved.push( module );
}
/**
* Get names of module that a module depends on, in their proper dependency order.
*
* @private
* @param {string[]} modules Array of string module names
* @return {Array} List of dependencies, including 'module'.
* @throws {Error} If an unregistered module or a dependency loop is encountered
*/
function resolve( modules ) {
// Always load base modules
var resolved = baseModules.slice();
for ( var i = 0; i < modules.length; i++ ) {
sortDependencies( modules[ i ], resolved );
}
return resolved;
}
/**
* Like #resolve(), except it will silently ignore modules that
* are missing or have missing dependencies.
*
* @private
* @param {string[]} modules Array of string module names
* @return {Array} List of dependencies.
*/
function resolveStubbornly( modules ) {
// Always load base modules
var resolved = baseModules.slice();
for ( var i = 0; i < modules.length; i++ ) {
var saved = resolved.slice();
try {
sortDependencies( modules[ i ], resolved );
} catch ( err ) {
resolved = saved;
// This module is not currently known, or has invalid dependencies.
//
// Most likely due to a cached reference after the module was
// removed, otherwise made redundant, or omitted from the registry
// by the ResourceLoader "target" system.
//
// These errors can be common, e.g. queuing an unavailable module
// unconditionally from the server-side is OK and should fail gracefully.
mw.log.warn( 'Skipped unavailable module ' + modules[ i ] );
// Do not track this error as an exception when the module:
// - Is valid, but gracefully filtered out by target system.
// - Was recently valid, but is still referenced in stale cache.
//
// Basically the only reason to track this as exception is when the error
// was circular or invalid dependencies. What the above scenarios have in
// common is that they don't register the module client-side.
if ( modules[ i ] in registry ) {
mw.trackError( {
exception: err,
source: 'resolve'
} );
}
}
}
return resolved;
}
/**
* Resolve a relative file path.
*
* For example, resolveRelativePath( '../foo.js', 'resources/src/bar/bar.js' )
* returns 'resources/src/foo.js'.
*
* @private
* @param {string} relativePath Relative file path, starting with ./ or ../
* @param {string} basePath Path of the file (not directory) relativePath is relative to
* @return {string|null} Resolved path, or null if relativePath does not start with ./ or ../
*/
function resolveRelativePath( relativePath, basePath ) {
// eslint-disable-next-line security/detect-unsafe-regex
var relParts = relativePath.match( /^((?:\.\.?\/)+)(.*)$/ );
if ( !relParts ) {
return null;
}
var baseDirParts = basePath.split( '/' );
// basePath looks like 'foo/bar/baz.js', so baseDirParts looks like [ 'foo', 'bar, 'baz.js' ]
// Remove the file component at the end, so that we are left with only the directory path
baseDirParts.pop();
var prefixes = relParts[ 1 ].split( '/' );
// relParts[ 1 ] looks like '../../', so prefixes looks like [ '..', '..', '' ]
// Remove the empty element at the end
prefixes.pop();
// For every ../ in the path prefix, remove one directory level from baseDirParts
var prefix;
while ( ( prefix = prefixes.pop() ) !== undefined ) {
if ( prefix === '..' ) {
baseDirParts.pop();
}
}
// If there's anything left of the base path, prepend it to the file path
return ( baseDirParts.length ? baseDirParts.join( '/' ) + '/' : '' ) + relParts[ 2 ];
}
/**
* Make a require() function scoped to a package file
*
* @private
* @param {Object} moduleObj Module object from the registry
* @param {string} basePath Path of the file this is scoped to. Used for relative paths.
* @return {Function}
*/
function makeRequireFunction( moduleObj, basePath ) {
return function require( moduleName ) {
var fileName = resolveRelativePath( moduleName, basePath );
if ( fileName === null ) {
// Not a relative path, so it's either a module name or,
// (if in test mode) a private file imported from another module.
return mw.loader.require( moduleName );
}
if ( hasOwn.call( moduleObj.packageExports, fileName ) ) {
// File has already been executed, return the cached result
return moduleObj.packageExports[ fileName ];
}
var scriptFiles = moduleObj.script.files;
if ( !hasOwn.call( scriptFiles, fileName ) ) {
throw new Error( 'Cannot require undefined file ' + fileName );
}
var result,
fileContent = scriptFiles[ fileName ];
if ( typeof fileContent === 'function' ) {
var moduleParam = { exports: {} };
fileContent( makeRequireFunction( moduleObj, fileName ), moduleParam, moduleParam.exports );
result = moduleParam.exports;
} else {
// fileContent is raw data (such as a JSON object), just pass it through
result = fileContent;
}
moduleObj.packageExports[ fileName ] = result;
return result;
};
}
/**
* Load and execute a script.
*
* @private
* @param {string} src URL to script, will be used as the src attribute in the script tag
* @param {Function} [callback] Callback to run after request resolution
* @param {string[]} [modules] List of modules being requested, for state to be marked as error
* in case the script fails to load
* @return {HTMLElement}
*/
function addScript( src, callback, modules ) {
// Use a <script> element rather than XHR. Using XHR changes the request
// headers (potentially missing a cache hit), and reduces caching in general
// since browsers cache XHR much less (if at all). And XHR means we retrieve
// text, so we'd need to eval, which then messes up line numbers.
// The drawback is that <script> does not offer progress events, feedback is
// only given after downloading, parsing, and execution have completed.
var script = document.createElement( 'script' );
script.src = src;
function onComplete() {
if ( script.parentNode ) {
script.parentNode.removeChild( script );
}
if ( callback ) {
callback();
callback = null;
}
}
script.onload = onComplete;
script.onerror = function () {
onComplete();
if ( modules ) {
for ( var i = 0; i < modules.length; i++ ) {
setAndPropagate( modules[ i ], 'error' );
}
}
};
document.head.appendChild( script );
return script;
}
/**
* Queue the loading and execution of a script for a particular module.
*
* This does for legacy debug mode what runScript() does for production.
*
* @private
* @param {string} src URL of the script
* @param {string} moduleName Name of currently executing module
* @param {Function} callback Callback to run after addScript() resolution
*/
function queueModuleScript( src, moduleName, callback ) {
pendingRequests.push( function () {
// Keep in sync with execute()/runScript().
if ( moduleName !== 'jquery' ) {
window.require = mw.loader.require;
window.module = registry[ moduleName ].module;
}
addScript( src, function () {
// 'module.exports' should not persist after the file is executed to
// avoid leakage to unrelated code. 'require' should be kept, however,
// as asynchronous access to 'require' is allowed and expected. (T144879)
delete window.module;
callback();
// Start the next one (if any)
if ( pendingRequests[ 0 ] ) {
pendingRequests.shift()();
} else {
handlingPendingRequests = false;
}
} );
} );
if ( !handlingPendingRequests && pendingRequests[ 0 ] ) {
handlingPendingRequests = true;
pendingRequests.shift()();
}
}
/**
* Utility function for execute()
*
* @ignore
* @param {string} url URL
* @param {string} [media] Media attribute
* @param {Node|null} [nextNode]
* @return {HTMLElement}
*/
function addLink( url, media, nextNode ) {
var el = document.createElement( 'link' );
el.rel = 'stylesheet';
if ( media ) {
el.media = media;
}
// If you end up here from an IE exception "SCRIPT: Invalid property value.",
// see #addEmbeddedCSS, T33676, T43331, and T49277 for details.
el.href = url;
addToHead( el, nextNode );
return el;
}
/**
* Evaluate in the global scope.
*
* This is used by MediaWiki user scripts, where it is (for example)
* important that `var` makes a global variable.
*
* @private
* @param {string} code JavaScript code
*/
function globalEval( code ) {
var script = document.createElement( 'script' );
script.text = code;
document.head.appendChild( script );
script.parentNode.removeChild( script );
}
/**
* Evaluate JS code using indirect eval().
*
* This is used by mw.loader.store. It is important that we protect the
* integrity of mw.loader's private variables (from accidental clashes
* or re-assignment), which means we can't use regular `eval()`.
*
* Optimization: This exists separately from globalEval(), because that
* involves slow DOM overhead.
*
* @private
* @param {string} code JavaScript code
*/
function indirectEval( code ) {
// See http://perfectionkills.com/global-eval-what-are-the-options/
// for an explanation of this syntax.
// eslint-disable-next-line no-eval
( 1, eval )( code );
}
/**
* Add one or more modules to the module load queue.
*
* See also #work().
*
* @private
* @param {string[]} dependencies Array of module names in the registry
* @param {Function} [ready] Callback to execute when all dependencies are ready
* @param {Function} [error] Callback to execute when any dependency fails
*/
function enqueue( dependencies, ready, error ) {
if ( allReady( dependencies ) ) {
// Run ready immediately
if ( ready ) {
ready();
}
return;
}
var failed = anyFailed( dependencies );
if ( failed !== false ) {
if ( error ) {
// Execute error immediately if any dependencies have errors
error(
new Error( 'Dependency ' + failed + ' failed to load' ),
dependencies
);
}
return;
}
// Not all dependencies are ready, add to the load queue...
// Add ready and error callbacks if they were given
if ( ready || error ) {
jobs.push( {
// Narrow down the list to modules that are worth waiting for
dependencies: dependencies.filter( function ( module ) {
var state = registry[ module ].state;
return state === 'registered' || state === 'loaded' || state === 'loading' || state === 'executing';
} ),
ready: ready,
error: error
} );
}
dependencies.forEach( function ( module ) {
// Only queue modules that are still in the initial 'registered' state
// (e.g. not ones already loading or loaded etc.).
if ( registry[ module ].state === 'registered' && queue.indexOf( module ) === -1 ) {
queue.push( module );
}
} );
mw.loader.work();
}
/**
* Executes a loaded module, making it ready to use
*
* @private
* @param {string} module Module name to execute
*/
function execute( module ) {
if ( registry[ module ].state !== 'loaded' ) {
throw new Error( 'Module in state "' + registry[ module ].state + '" may not execute: ' + module );
}
registry[ module ].state = 'executing';
$CODE.profileExecuteStart();
var runScript = function () {
$CODE.profileScriptStart();
var script = registry[ module ].script;
var markModuleReady = function () {
$CODE.profileScriptEnd();
setAndPropagate( module, 'ready' );
};
var nestedAddScript = function ( arr, offset ) {
// Recursively call queueModuleScript() in its own callback
// for each element of arr.
if ( offset >= arr.length ) {
// We're at the end of the array
markModuleReady();
return;
}
queueModuleScript( arr[ offset ], module, function () {
nestedAddScript( arr, offset + 1 );
} );
};
try {
if ( Array.isArray( script ) ) {
nestedAddScript( script, 0 );
} else if ( typeof script === 'function' ) {
// Keep in sync with queueModuleScript() for debug mode
if ( module === 'jquery' ) {
// This is a special case for when 'jquery' itself is being loaded.
// - The standard jquery.js distribution does not set `window.jQuery`
// in CommonJS-compatible environments (Node.js, AMD, RequireJS, etc.).
// - MediaWiki's 'jquery' module also bundles jquery.migrate.js, which
// in a CommonJS-compatible environment, will use require('jquery'),
// but that can't work when we're still inside that module.
script();
} else {
// Pass jQuery twice so that the signature of the closure which wraps
// the script can bind both '$' and 'jQuery'.
script( window.$, window.$, mw.loader.require, registry[ module ].module );
}
markModuleReady();
} else if ( typeof script === 'object' && script !== null ) {
var mainScript = script.files[ script.main ];
if ( typeof mainScript !== 'function' ) {
throw new Error( 'Main file in module ' + module + ' must be a function' );
}
// jQuery parameters are not passed for multi-file modules
mainScript(
makeRequireFunction( registry[ module ], script.main ),
registry[ module ].module,
registry[ module ].module.exports
);
markModuleReady();
} else if ( typeof script === 'string' ) {
// Site and user modules are legacy scripts that run in the global scope.
// This is transported as a string instead of a function to avoid needing
// to use string manipulation to undo the function wrapper.
globalEval( script );
markModuleReady();
} else {
// Module without script
markModuleReady();
}
} catch ( e ) {
// Use mw.trackError instead of mw.log because these errors are common in production mode
// (e.g. undefined variable), and mw.log is only enabled in debug mode.
setAndPropagate( module, 'error' );
$CODE.profileScriptEnd();
mw.trackError( {
exception: e,
module: module,
source: 'module-execute'
} );
}
};
// Emit deprecation warnings
if ( registry[ module ].deprecationWarning ) {
mw.log.warn( registry[ module ].deprecationWarning );
}
// Add localizations to message system
if ( registry[ module ].messages ) {
mw.messages.set( registry[ module ].messages );
}
// Initialise templates
if ( registry[ module ].templates ) {
mw.templates.set( module, registry[ module ].templates );
}
// Adding of stylesheets is asynchronous via addEmbeddedCSS().
// The below function uses a counting semaphore to make sure we don't call
// runScript() until after this module's stylesheets have been inserted
// into the DOM.
var cssPending = 0;
var cssHandle = function () {
// Increase semaphore, when creating a callback for addEmbeddedCSS.
cssPending++;
return function () {
// Decrease semaphore, when said callback is invoked.
cssPending--;
if ( cssPending === 0 ) {
// Paranoia:
// This callback is exposed to addEmbeddedCSS, which is outside the execute()
// function and is not concerned with state-machine integrity. In turn,
// addEmbeddedCSS() actually exposes stuff further via requestAnimationFrame.
// If increment and decrement callbacks happen in the wrong order, or start
// again afterwards, then this branch could be reached multiple times.
// To protect the integrity of the state-machine, prevent that from happening
// by making runScript() cannot be called more than once. We store a private
// reference when we first reach this branch, then deference the original, and
// call our reference to it.
var runScriptCopy = runScript;
runScript = undefined;
runScriptCopy();
}
};
};
// Process styles (see also mw.loader.impl)
// * { "css": [css, ..] }
// * { "url": { <media>: [url, ..] } }
var style = registry[ module ].style;
if ( style ) {
// Array of CSS strings under key 'css'
// { "css": [css, ..] }
if ( 'css' in style ) {
for ( var i = 0; i < style.css.length; i++ ) {
addEmbeddedCSS( style.css[ i ], cssHandle() );
}
}
// Plain object with array of urls under a media-type key
// { "url": { <media>: [url, ..] } }
if ( 'url' in style ) {
for ( var media in style.url ) {
var urls = style.url[ media ];
for ( var j = 0; j < urls.length; j++ ) {
addLink( urls[ j ], media, marker );
}
}
}
}
// End profiling of execute()-self before we call runScript(),
// which we want to measure separately without overlap.
$CODE.profileExecuteEnd();
if ( module === 'user' ) {
// Implicit dependency on the site module. Not a real dependency because it should
// run after 'site' regardless of whether it succeeds or fails.
// Note: This is a simplified version of mw.loader.using(), inlined here because
// mw.loader.using() is part of mediawiki.base (depends on jQuery; T192623).
var siteDeps;
var siteDepErr;
try {
siteDeps = resolve( [ 'site' ] );
} catch ( e ) {
siteDepErr = e;
runScript();
}
if ( !siteDepErr ) {
enqueue( siteDeps, runScript, runScript );
}
} else if ( cssPending === 0 ) {
// Regular module without styles
runScript();
}
// else: runScript will get called via cssHandle()
}
function sortQuery( o ) {
var sorted = {};
var list = [];
for ( var key in o ) {
list.push( key );
}
list.sort();
for ( var i = 0; i < list.length; i++ ) {
sorted[ list[ i ] ] = o[ list[ i ] ];
}
return sorted;
}
/**
* Converts a module map of the form `{ foo: [ 'bar', 'baz' ], bar: [ 'baz, 'quux' ] }`
* to a query string of the form `foo.bar,baz|bar.baz,quux`.
*
* See `ResourceLoader::makePackedModulesString()` in PHP, of which this is a port.
* On the server, unpacking is done by `ResourceLoader::expandModuleNames()`.
*
* Note: This is only half of the logic, the other half has to be in #batchRequest(),
* because its implementation needs to keep track of potential string size in order
* to decide when to split the requests due to url size.
*
* @typedef {Object} ModuleString
* @property {string} str Module query string
* @property {Array} list List of module names in matching order
*
* @private
* @param {Object} moduleMap Module map
* @return {ModuleString}
*/
function buildModulesString( moduleMap ) {
var str = [];
var list = [];
var p;
function restore( suffix ) {
return p + suffix;
}
for ( var prefix in moduleMap ) {
p = prefix === '' ? '' : prefix + '.';
str.push( p + moduleMap[ prefix ].join( ',' ) );
list.push.apply( list, moduleMap[ prefix ].map( restore ) );
}
return {
str: str.join( '|' ),
list: list
};
}
/**
* @private
* @param {Object} params Map of parameter names to values
* @return {string}
*/
function makeQueryString( params ) {
// Optimisation: This is a fairly hot code path with batchRequest() loops.
// Avoid overhead from Object.keys and Array.forEach.
// String concatenation is faster than array pushing and joining, see
// https://phabricator.wikimedia.org/P19931
var str = '';
for ( var key in params ) {
// Parameters are separated by &, added before all parameters other than
// the first
str += ( str ? '&' : '' ) + encodeURIComponent( key ) + '=' +
encodeURIComponent( params[ key ] );
}
return str;
}
/**
* Create network requests for a batch of modules.
*
* This is an internal method for #work(). This must not be called directly
* unless the modules are already registered, and no request is in progress,
* and the module state has already been set to `loading`.
*
* @private
* @param {string[]} batch
*/
function batchRequest( batch ) {
if ( !batch.length ) {
return;
}
var sourceLoadScript, currReqBase, moduleMap;
/**
* Start the currently drafted request to the server.
*
* @ignore
*/
function doRequest() {
// Optimisation: Inherit (Object.create), not copy ($.extend)
var query = Object.create( currReqBase ),
packed = buildModulesString( moduleMap );
query.modules = packed.str;
// The packing logic can change the effective order, even if the input was
// sorted. As such, the call to getCombinedVersion() must use this
// effective order to ensure that the combined version will match the hash
// expected by the server based on combining versions from the module
// query string in-order. (T188076)
query.version = getCombinedVersion( packed.list );
query = sortQuery( query );
addScript( sourceLoadScript + '?' + makeQueryString( query ), null, packed.list );
}
// Always order modules alphabetically to help reduce cache
// misses for otherwise identical content.
batch.sort();
// Query parameters common to all requests
var reqBase = $VARS.reqBase;
// Split module list by source and by group.
var splits = Object.create( null );
for ( var b = 0; b < batch.length; b++ ) {
var bSource = registry[ batch[ b ] ].source;
var bGroup = registry[ batch[ b ] ].group;
if ( !splits[ bSource ] ) {
splits[ bSource ] = Object.create( null );
}
if ( !splits[ bSource ][ bGroup ] ) {
splits[ bSource ][ bGroup ] = [];
}
splits[ bSource ][ bGroup ].push( batch[ b ] );
}
for ( var source in splits ) {
sourceLoadScript = sources[ source ];
for ( var group in splits[ source ] ) {
// Cache access to currently selected list of
// modules for this group from this source.
var modules = splits[ source ][ group ];
// Query parameters common to requests for this module group
// Optimisation: Inherit (Object.create), not copy ($.extend)
currReqBase = Object.create( reqBase );
// User modules require a user name in the query string.
if ( group === $VARS.groupUser && mw.config.get( 'wgUserName' ) !== null ) {
currReqBase.user = mw.config.get( 'wgUserName' );
}
// In addition to currReqBase, doRequest() will also add 'modules' and 'version'.
// > '&modules='.length === 9
// > '&version=12345'.length === 14
// > 9 + 14 = 23
var currReqBaseLength = makeQueryString( currReqBase ).length + 23;
// We may need to split up the request to honor the query string length limit,
// so build it piece by piece. `length` does not include the characters from
// the request base, see below
var length = 0;
moduleMap = Object.create( null ); // { prefix: [ suffixes ] }
for ( var i = 0; i < modules.length; i++ ) {
// Determine how many bytes this module would add to the query string
var lastDotIndex = modules[ i ].lastIndexOf( '.' ),
prefix = modules[ i ].slice( 0, Math.max( 0, lastDotIndex ) ),
suffix = modules[ i ].slice( lastDotIndex + 1 ),
bytesAdded = moduleMap[ prefix ] ?
suffix.length + 3 : // '%2C'.length == 3
modules[ i ].length + 3; // '%7C'.length == 3
// If the url would become too long, create a new one, but don't create empty requests.
// The value of `length` only reflects the request-specific bytes relating to the
// accumulated entries in moduleMap so far. It does not include the base length,
// which we account for separately with `currReqBaseLength` so that length is 0
// when moduleMap is empty.
if ( length && length + currReqBaseLength + bytesAdded > mw.loader.maxQueryLength ) {
// Dispatch what we've got...
doRequest();
// .. and start preparing a new request.
length = 0;
moduleMap = Object.create( null );
}
if ( !moduleMap[ prefix ] ) {
moduleMap[ prefix ] = [];
}
length += bytesAdded;
moduleMap[ prefix ].push( suffix );
}
// Optimization: Skip `length` check.
// moduleMap will contain at least one module here. The loop above leaves the last module
// undispatched (and maybe some before it), so for moduleMap to be empty here, there must
// have been no modules to iterate in the current group to start with, but we only create
// a group in `splits` when the first module in the group is seen, so there are always
// modules in the group when this code is reached.
doRequest();
}
}
}
/**
* @private
* @param {string[]} implementations Array containing pieces of JavaScript code in the
* form of calls to mw.loader#impl().
* @param {Function} cb Callback in case of failure
* @param {Error} cb.err
* @param {number} [offset] Integer offset into implementations to start at
*/
function asyncEval( implementations, cb, offset ) {
if ( !implementations.length ) {
return;
}
offset = offset || 0;
mw.requestIdleCallback( function ( deadline ) {
asyncEvalTask( deadline, implementations, cb, offset );
} );
}
/**
* Idle callback for asyncEval
*
* @private
* @param {IdleDeadline} deadline
* @param {string[]} implementations
* @param {Function} cb
* @param {Error} cb.err
* @param {number} offset
*/
function asyncEvalTask( deadline, implementations, cb, offset ) {
for ( var i = offset; i < implementations.length; i++ ) {
if ( deadline.timeRemaining() <= 0 ) {
asyncEval( implementations, cb, i );
return;
}
try {
indirectEval( implementations[ i ] );
} catch ( err ) {
cb( err );
}
}
}
/**
* Make a versioned key for a specific module.
*
* @private
* @param {string} module Module name
* @return {string|null} Module key in format '`[name]@[version]`',
* or null if the module does not exist
*/
function getModuleKey( module ) {
return module in registry ? ( module + '@' + registry[ module ].version ) : null;
}
/**
* @private
* @param {string} key Module name or '`[name]@[version]`'
* @return {Object}
*/
function splitModuleKey( key ) {
// Module names may contain '@' but version strings may not, so the last '@' is the delimiter
var index = key.lastIndexOf( '@' );
// If the key doesn't contain '@' or starts with it, the whole thing is the module name
if ( index === -1 || index === 0 ) {
return {
name: key,
version: ''
};
}
return {
name: key.slice( 0, index ),
version: key.slice( index + 1 )
};
}
/**
* @private
* @param {string} module
* @param {string} [version]
* @param {string[]} [dependencies]
* @param {string} [group]
* @param {string} [source]
* @param {string} [skip]
*/
function registerOne( module, version, dependencies, group, source, skip ) {
if ( module in registry ) {
throw new Error( 'module already registered: ' + module );
}
registry[ module ] = {
// Exposed to execute() for mw.loader.impl() closures.
// Import happens via require().
module: {
exports: {}
},
// module.export objects for each package file inside this module
packageExports: {},
version: version || '',
dependencies: dependencies || [],
group: typeof group === 'undefined' ? null : group,
source: typeof source === 'string' ? source : 'local',
state: 'registered',
skip: typeof skip === 'string' ? skip : null
};
}
/* Public Members */
mw.loader = {
/**
* The module registry is exposed as an aid for debugging and inspecting page
* state; it is not a public interface for modifying the registry.
*
* @see #registry
* @property {Object}
* @private
*/
moduleRegistry: registry,
/**
* Exposed for testing and debugging only.
*
* @see #batchRequest
* @property {number}
* @private
*/
maxQueryLength: $VARS.maxQueryLength,
addStyleTag: newStyleTag,
// Exposed for internal use only. Documented as @private.
addScriptTag: addScript,
// Exposed for internal use only. Documented as @private.
addLinkTag: addLink,
// Exposed for internal use only. Documented as @private.
enqueue: enqueue,
// Exposed for internal use only. Documented as @private.
resolve: resolve,
/**
* Start loading of all queued module dependencies.
*
* @private
*/
work: function () {
store.init();
var q = queue.length,
storedImplementations = [],
storedNames = [],
requestNames = [],
batch = new Set();
// Iterate the list of requested modules, and do one of three things:
// - 1) Nothing (if already loaded or being loaded).
// - 2) Eval the cached implementation from the module store.
// - 3) Request from network.
while ( q-- ) {
var module = queue[ q ];
// Only consider modules which are the initial 'registered' state,
// and ignore duplicates
if ( mw.loader.getState( module ) === 'registered' &&
!batch.has( module )
) {
// Progress the state machine
registry[ module ].state = 'loading';
batch.add( module );
var implementation = store.get( module );
if ( implementation ) {
// Module store enabled and contains this module/version
storedImplementations.push( implementation );
storedNames.push( module );
} else {
// Module store disabled or doesn't have this module/version
requestNames.push( module );
}
}
}
// Now that the queue has been processed into a batch, clear the queue.
// This MUST happen before we initiate any eval or network request. Otherwise,
// it is possible for a cached script to instantly trigger the same work queue
// again; all before we've cleared it causing each request to include modules
// which are already loaded.
queue = [];
asyncEval( storedImplementations, function ( err ) {
// Not good, the cached mw.loader.impl calls failed! This should
// never happen, barring ResourceLoader bugs, browser bugs and PEBKACs.
// Depending on how corrupt the string is, it is likely that some
// modules' impl() succeeded while the ones after the error will
// never run and leave their modules in the 'loading' state forever.
store.stats.failed++;
// Since this is an error not caused by an individual module but by
// something that infected the implement call itself, don't take any
// risks and clear everything in this cache.
store.clear();
mw.trackError( {
exception: err,
source: 'store-eval'
} );
// For any failed ones, fallback to requesting from network
var failed = storedNames.filter( function ( name ) {
return registry[ name ].state === 'loading';
} );
batchRequest( failed );
} );
batchRequest( requestNames );
},
/**
* Register a source.
*
* The #work() method will use this information to split up requests by source.
*
* @example
* mw.loader.addSource( { mediawikiwiki: 'https://www.mediawiki.org/w/load.php' } );
*
* @private
* @param {Object} ids An object mapping ids to load.php end point urls
* @throws {Error} If source id is already registered
*/
addSource: function ( ids ) {
for ( var id in ids ) {
if ( id in sources ) {
throw new Error( 'source already registered: ' + id );
}
sources[ id ] = ids[ id ];
}
},
/**
* Register a module, letting the system know about it and its properties.
*
* The startup module calls this method.
*
* When using multiple module registration by passing an array, dependencies that
* are specified as references to modules within the array will be resolved before
* the modules are registered.
*
* @param {string|Array} modules Module name or array of arrays, each containing
* a list of arguments compatible with this method
* @param {string} [version] Module version hash (falls backs to empty string)
* @param {string[]} [dependencies] Array of module names on which this module depends.
* @param {string} [group=null] Group which the module is in
* @param {string} [source='local'] Name of the source
* @param {string} [skip=null] Script body of the skip function
* @private
*/
register: function ( modules ) {
if ( typeof modules !== 'object' ) {
registerOne.apply( null, arguments );
return;
}
// Need to resolve indexed dependencies:
// ResourceLoader uses an optimisation to save space which replaces module
// names in dependency lists with the index of that module within the
// array of module registration data if it exists. The benefit is a significant
// reduction in the data size of the startup module. This loop changes
// those dependency lists back to arrays of strings.
function resolveIndex( dep ) {
return typeof dep === 'number' ? modules[ dep ][ 0 ] : dep;
}
for ( var i = 0; i < modules.length; i++ ) {
var deps = modules[ i ][ 2 ];
if ( deps ) {
for ( var j = 0; j < deps.length; j++ ) {
deps[ j ] = resolveIndex( deps[ j ] );
}
}
// Optimisation: Up to 55% faster.
// Typically register() is called exactly once on a page, and with a batch.
// See <https://gist.github.com/Krinkle/f06fdb3de62824c6c16f02a0e6ce0e66>
// Benchmarks taught us that the code for adding an object to `registry`
// should be in a function that has only one signature and does no arguments
// manipulation.
// JS semantics make it hard to optimise recursion to a different
// signature of itself, hence we moved this out.
registerOne.apply( null, modules[ i ] );
}
},
/**
* Implement a module given the components of the module.
*
* See #impl for a full description of the parameters.
*
* Prior to MW 1.41, this was used internally, but now it is only kept
* for backwards compatibility.
*
* Does not support mw.loader.store caching.
*
* @param {string} module
* @param {Function|Array|string|Object} [script]
* @param {Object} [style]
* @param {Object} [messages] List of key/value pairs to be added to mw#messages.
* @param {Object} [templates] List of key/value pairs to be added to mw#templates.
* @param {string|null} [deprecationWarning] Deprecation warning if any
* @private
*/
implement: function ( module, script, style, messages, templates, deprecationWarning ) {
var split = splitModuleKey( module ),
name = split.name,
version = split.version;
// Automatically register module
if ( !( name in registry ) ) {
mw.loader.register( name );
}
// Check for duplicate implementation
if ( registry[ name ].script !== undefined ) {
throw new Error( 'module already implemented: ' + name );
}
registry[ name ].version = version;
registry[ name ].declarator = null; // not supported
registry[ name ].script = script;
registry[ name ].style = style;
registry[ name ].messages = messages;
registry[ name ].templates = templates;
registry[ name ].deprecationWarning = deprecationWarning;
// The module may already have been marked as erroneous
if ( registry[ name ].state !== 'error' && registry[ name ].state !== 'missing' ) {
setAndPropagate( name, 'loaded' );
}
},
/**
* Implement a module given a function which returns the components of the module
*
* @param {Function} declarator
*
* The declarator should return an array with the following keys:
*
* - 0. {string} module Name of module and current module version. Formatted
* as '`[name]@[version]`". This version should match the requested version
* (from #batchRequest and #registry). This avoids race conditions (T117587).
*
* - 1. {Function|Array|string|Object} [script] Module code. This can be a function,
* a list of URLs to load via `<script src>`, a string for `globalEval()`, or an
* object like {"files": {"foo.js":function, "bar.js": function, ...}, "main": "foo.js"}.
* If an object is provided, the main file will be executed immediately, and the other
* files will only be executed if loaded via require(). If a function or string is
* provided, it will be executed/evaluated immediately. If an array is provided, all
* URLs in the array will be loaded immediately, and executed as soon as they arrive.
*
* - 2. {Object} [style] Should follow one of the following patterns:
*
* { "css": [css, ..] }
* { "url": { (media): [url, ..] } }
*
* The reason css strings are not concatenated anymore is T33676. We now check
* whether it's safe to extend the stylesheet.
*
* - 3. {Object} [messages] List of key/value pairs to be added to mw#messages.
* - 4. {Object} [templates] List of key/value pairs to be added to mw#templates.
* - 5. {String|null} [deprecationWarning] Deprecation warning if any
*
* The declarator must not use any scope variables, since it will be serialized with
* Function.prototype.toString() and later restored and executed in the global scope.
*
* The elements are all optional except the name.
* @private
*/
impl: function ( declarator ) {
var data = declarator(),
module = data[ 0 ],
script = data[ 1 ] || null,
style = data[ 2 ] || null,
messages = data[ 3 ] || null,
templates = data[ 4 ] || null,
deprecationWarning = data[ 5 ] || null,
split = splitModuleKey( module ),
name = split.name,
version = split.version;
// Automatically register module
if ( !( name in registry ) ) {
mw.loader.register( name );
}
// Check for duplicate implementation
if ( registry[ name ].script !== undefined ) {
throw new Error( 'module already implemented: ' + name );
}
// Without this reset, if there is a version mismatch between the
// requested and received module version, then mw.loader.store would
// cache the response under the requested key. Thus poisoning the cache
// indefinitely with a stale value. (T117587)
registry[ name ].version = version;
// Attach components
registry[ name ].declarator = declarator;
registry[ name ].script = script;
registry[ name ].style = style;
registry[ name ].messages = messages;
registry[ name ].templates = templates;
registry[ name ].deprecationWarning = deprecationWarning;
// The module may already have been marked as erroneous
if ( registry[ name ].state !== 'error' && registry[ name ].state !== 'missing' ) {
setAndPropagate( name, 'loaded' );
}
},
/**
* Load an external script or one or more modules.
*
* This method takes a list of unrelated modules. Use cases:
*
* - A web page will be composed of many different widgets. These widgets independently
* queue their ResourceLoader modules (`OutputPage::addModules()`). If any of them
* have problems, or are no longer known (e.g. cached HTML), the other modules
* should still be loaded.
* - This method is used for preloading, which must not throw. Later code that
* calls #using() will handle the error.
*
* @param {string|Array} modules Either the name of a module, array of modules,
* or a URL of an external script or style
* @param {string} [type='text/javascript'] MIME type to use if calling with a URL of an
* external script or style; acceptable values are "text/css" and
* "text/javascript"; if no type is provided, text/javascript is assumed.
* @throws {Error} If type is invalid
*/
load: function ( modules, type ) {
// eslint-disable-next-line security/detect-unsafe-regex
if ( typeof modules === 'string' && /^(https?:)?\/?\//.test( modules ) ) {
// Called with a url like so:
// - "https://example.org/x.js"
// - "http://example.org/x.js"
// - "//example.org/x.js"
// - "/x.js"
if ( type === 'text/css' ) {
addLink( modules );
} else if ( type === 'text/javascript' || type === undefined ) {
addScript( modules );
} else {
// Unknown type
throw new Error( 'Invalid type ' + type );
}
} else {
// One or more modules
modules = typeof modules === 'string' ? [ modules ] : modules;
// Resolve modules into a flat list for internal queuing.
// This also filters out unknown modules and modules with
// unknown dependencies, allowing the rest to continue. (T36853)
// Omit ready and error parameters, we don't have callbacks
enqueue( resolveStubbornly( modules ) );
}
},
/**
* Change the state of one or more modules.
*
* @param {Object} states Object of module name/state pairs
* @private
*/
state: function ( states ) {
for ( var module in states ) {
if ( !( module in registry ) ) {
mw.loader.register( module );
}
setAndPropagate( module, states[ module ] );
}
},
/**
* Get the state of a module.
*
* Possible states for the public API:
*
* - `registered`: The module is available for loading but not yet requested.
* - `loading`, `loaded`, or `executing`: The module is currently being loaded.
* - `ready`: The module was succesfully and fully loaded.
* - `error`: The module or one its dependencies has failed to load, e.g. due to
* uncaught error from the module's script files.
* - `missing`: The module was requested but is not defined according to the server.
*
* Internal mw.loader state machine:
*
* - `registered`:
* The module is known to the system but not yet required.
* Meta data is stored by mw.loader#register.
* Calls to that method are generated server-side by StartupModule.
* - `loading`:
* The module was required through mw.loader (either directly or as dependency of
* another module). The client will fetch module contents from mw.loader.store
* or from the server. The contents should later be received by mw.loader#implement.
* - `loaded`:
* The module has been received by mw.loader#implement.
* Once the module has no more dependencies in-flight, the module will be executed,
* controlled via #setAndPropagate and #doPropagation.
* - `executing`:
* The module is being executed (apply messages and stylesheets, execute scripts)
* by mw.loader#execute.
* - `ready`:
* The module has been successfully executed.
* - `error`:
* The module (or one of its dependencies) produced an uncaught error during execution.
* - `missing`:
* The module was registered client-side and requested, but the server denied knowledge
* of the module's existence.
*
* @param {string} module Name of module
* @return {string|null} The state, or null if the module (or its state) is not
* in the registry.
*/
getState: function ( module ) {
return module in registry ? registry[ module ].state : null;
},
/**
* Get the exported value of a module.
*
* This static method is publicly exposed for debugging purposes
* only and must not be used in production code. In production code,
* please use the dynamically provided `require()` function instead.
*
* In case of lazy-loaded modules via mw.loader#using(), the returned
* Promise provides the function, see #using() for examples.
*
* @private
* @since 1.27
* @param {string} moduleName Module name
* @return {any} Exported value
*/
require: function ( moduleName ) {
var path;
if ( window.QUnit ) {
// Comply with Node specification
// https://nodejs.org/docs/v20.1.0/api/modules.html#all-together
//
// > Interpret X as a combination of NAME and SUBPATH, where the NAME
// > may have a "@scope/" prefix and the subpath begins with a slash (`/`).
//
// Regex inspired by Node [1], but simplified to suite our purposes
// and split in two in order to keep the Regex Star Height under 2,
// as per ESLint security/detect-unsafe-regex.
//
// These patterns match "@scope/module/dir/file.js" and "module/dir/file.js"
// respectively. They must not match "module.name" or "@scope/module.name".
//
// [1] https://github.com/nodejs/node/blob/v20.1.0/lib/internal/modules/cjs/loader.js#L554-L560
var paths = moduleName.startsWith( '@' ) ?
/^(@[^/]+\/[^/]+)\/(.*)$/.exec( moduleName ) :
// eslint-disable-next-line no-mixed-spaces-and-tabs
/^([^/]+)\/(.*)$/.exec( moduleName );
if ( paths ) {
moduleName = paths[ 1 ];
path = paths[ 2 ];
}
}
// Only ready modules can be required
if ( mw.loader.getState( moduleName ) !== 'ready' ) {
// Module may've forgotten to declare a dependency
throw new Error( 'Module "' + moduleName + '" is not loaded' );
}
return path ?
makeRequireFunction( registry[ moduleName ], '' )( './' + path ) :
registry[ moduleName ].module.exports;
}
};
var hasPendingFlush = false,
hasPendingWrites = false;
/**
* Actually update the store
*
* @see #requestUpdate
* @private
*/
function flushWrites() {
// Process queued module names, serialise their contents to the in-memory store.
while ( store.queue.length ) {
store.set( store.queue.shift() );
}
// Optimization: Don't reserialize the entire store and rewrite localStorage,
// if no module was added or changed.
if ( hasPendingWrites ) {
// Remove anything from the in-memory store that came from previous page
// loads that no longer corresponds with current module names and versions.
store.prune();
try {
// Replacing the content of the module store might fail if the new
// contents would exceed the browser's localStorage size limit. To
// avoid clogging the browser with stale data, always remove the old
// value before attempting to store a new one.
localStorage.removeItem( store.key );
localStorage.setItem( store.key, JSON.stringify( {
items: store.items,
vary: store.vary,
// Store with 1e7 ms accuracy (1e4 seconds, or ~ 2.7 hours),
// which is enough for the purpose of expiring after ~ 30 days.
asOf: Math.ceil( Date.now() / 1e7 )
} ) );
} catch ( e ) {
mw.trackError( {
exception: e,
source: 'store-localstorage-update'
} );
}
}
// Let the next call to requestUpdate() create a new timer.
hasPendingFlush = hasPendingWrites = false;
}
// We use a local variable `store` so that its easier to access, but also need to set
// this in mw.loader so its exported - combine the two
/**
* On browsers that implement the localStorage API, the module store serves as a
* smart complement to the browser cache. Unlike the browser cache, the module store
* can slice a concatenated response from ResourceLoader into its constituent
* modules and cache each of them separately, using each module's versioning scheme
* to determine when the cache should be invalidated.
*
* @private
* @singleton
* @class mw.loader.store
* @ignore
*/
mw.loader.store = store = {
// Whether the store is in use on this page.
enabled: null,
// The contents of the store, mapping '[name]@[version]' keys
// to module implementations.
items: {},
// Names of modules to be stored during the next update.
// See add() and update().
queue: [],
// Cache hit stats
stats: { hits: 0, misses: 0, expired: 0, failed: 0 },
/**
* The localStorage key for the entire module store. The key references
* $wgDBname to prevent clashes between wikis which share a common host.
*
* @property {string}
*/
key: $VARS.storeKey,
/**
* A string containing various factors by which the module cache should vary.
*
* Defined by ResourceLoader\StartupModule::getStoreVary() in PHP.
*
* @property {string}
*/
vary: $VARS.storeVary,
/**
* Initialize the store.
*
* Retrieves store from localStorage and (if successfully retrieved) decoding
* the stored JSON value to a plain object.
*/
init: function () {
// Init only once per page
if ( this.enabled === null ) {
this.enabled = false;
if ( $VARS.storeEnabled ) {
this.load();
} else {
// Clear any previous store to free up space. (T66721)
this.clear();
}
}
},
/**
* Internal helper for init(). Separated for ease of testing.
*/
load: function () {
// These are the scenarios to think about:
//
// 1. localStorage is disallowed by the browser.
// This means `localStorage.getItem` throws.
// The store stays disabled.
//
// 2. localStorage did not contain our store key.
// This usually means the browser has a cold cache for this site,
// and thus localStorage.getItem returns null.
// The store will be enabled, and `items` starts fresh.
//
// 3. localStorage contains parseable data, but it's not usable.
// This means the data is too old, or is not valid for mw.loader.store.vary
// (e.g. user switched skin or language).
// The store will be enabled, and `items` starts fresh.
//
// 4. localStorage contains invalid JSON data.
// This means the data was corrupted, and `JSON.parse` throws.
// The store will be enabled, and `items` starts fresh.
//
// 5. localStorage contains valid and usable JSON.
// This means we have a warm cache from a previous visit.
// The store will be enabled, and `items` starts with the stored data.
try {
var raw = localStorage.getItem( this.key );
// If we make it here, localStorage is enabled and available.
// The rest of the function may fail, but that only affects what we load from
// the cache. We'll still enable the store to allow storing new modules.
this.enabled = true;
// If getItem returns null, JSON.parse() will cast to string and re-parse, still null.
var data = JSON.parse( raw );
if ( data &&
data.vary === this.vary &&
data.items &&
// Only use if it's been less than 30 days since the data was written
// 30 days = 2,592,000 s = 2,592,000,000 ms = ± 259e7 ms
Date.now() < ( data.asOf * 1e7 ) + 259e7
) {
// The data is not corrupt, matches our vary context, and has not expired.
this.items = data.items;
}
} catch ( e ) {
// Ignore error from localStorage or JSON.parse.
// Don't print any warning (T195647).
}
},
/**
* Retrieve a module from the store and update cache hit stats.
*
* @param {string} module Module name
* @return {string|boolean} Module implementation or false if unavailable
*/
get: function ( module ) {
if ( this.enabled ) {
var key = getModuleKey( module );
if ( key in this.items ) {
this.stats.hits++;
return this.items[ key ];
}
this.stats.misses++;
}
return false;
},
/**
* Queue the name of a module that the next update should consider storing.
*
* @since 1.32
* @param {string} module Module name
*/
add: function ( module ) {
if ( this.enabled ) {
this.queue.push( module );
this.requestUpdate();
}
},
/**
* Add the contents of the named module to the in-memory store.
*
* This method does not guarantee that the module will be stored.
* Inspection of the module's meta data and size will ultimately decide that.
*
* This method is considered internal to mw.loader.store and must only
* be called if the store is enabled.
*
* @private
* @param {string} module Module name
*/
set: function ( module ) {
var descriptor = registry[ module ],
key = getModuleKey( module );
if (
// Already stored a copy of this exact version
key in this.items ||
// Module failed to load
!descriptor ||
descriptor.state !== 'ready' ||
// Unversioned, private, or site-/user-specific
!descriptor.version ||
descriptor.group === $VARS.groupPrivate ||
descriptor.group === $VARS.groupUser ||
// Legacy descriptor, registered with mw.loader.implement
!descriptor.declarator
) {
// Decline to store
return;
}
var script = String( descriptor.declarator );
// Modules whose serialised form exceeds 100 kB won't be stored (T66721).
if ( script.length > 1e5 ) {
return;
}
var srcParts = [
'mw.loader.impl(',
script,
');\n'
];
if ( $VARS.sourceMapLinks ) {
srcParts.push( '// Saved in localStorage at ', ( new Date() ).toISOString(), '\n' );
var sourceLoadScript = sources[ descriptor.source ];
var query = Object.create( $VARS.reqBase );
query.modules = module;
query.version = getCombinedVersion( [ module ] );
query = sortQuery( query );
srcParts.push(
'//# sourceURL=',
// Use absolute URL so that Firefox console stack trace links will work
( new URL( sourceLoadScript, location ) ).href,
'?',
makeQueryString( query ),
'\n'
);
query.sourcemap = '1';
query = sortQuery( query );
srcParts.push(
'//# sourceMappingURL=',
sourceLoadScript,
'?',
makeQueryString( query )
);
}
this.items[ key ] = srcParts.join( '' );
hasPendingWrites = true;
},
/**
* Iterate through the module store, removing any item that does not correspond
* (in name and version) to an item in the module registry.
*/
prune: function () {
for ( var key in this.items ) {
// key is in the form [name]@[version], slice to get just the name
// to provide to getModuleKey, which will return a key in the same
// form but with the latest version
if ( getModuleKey( splitModuleKey( key ).name ) !== key ) {
this.stats.expired++;
delete this.items[ key ];
}
}
},
/**
* Clear the entire module store right now.
*/
clear: function () {
this.items = {};
try {
localStorage.removeItem( this.key );
} catch ( e ) {}
},
/**
* Request a sync of the in-memory store back to persisted localStorage.
*
* This function debounces updates. The debouncing logic should account
* for the following factors:
*
* - Writing to localStorage is an expensive operation that must not happen
* during the critical path of initialising and executing module code.
* Instead, it should happen at a later time after modules have been given
* time and priority to do their thing first.
*
* - This method is called from mw.loader.store.add(), which will be called
* hundreds of times on a typical page, including within the same call-stack
* and eventloop-tick. This is because responses from load.php happen in
* batches. As such, we want to allow all modules from the same load.php
* response to be written to disk with a single flush, not many.
*
* - Repeatedly deleting and creating timers is non-trivial.
*
* - localStorage is shared by all pages from the same origin, if multiple
* pages are loaded with different module sets, the possibility exists that
* modules saved by one page will be clobbered by another. The impact of
* this is minor, it merely causes a less efficient cache use, and the
* problem would be corrected by subsequent page views.
*
* This method is considered internal to mw.loader.store and must only
* be called if the store is enabled.
*
* @private
* @method
*/
requestUpdate: function () {
// On the first call to requestUpdate(), create a timer that
// waits at least two seconds, then calls onTimeout.
// The main purpose is to allow the current batch of load.php
// responses to complete before we do anything. This batch can
// trigger many hundreds of calls to requestUpdate().
if ( !hasPendingFlush ) {
hasPendingFlush = setTimeout(
// Defer the actual write via requestIdleCallback
function () {
mw.requestIdleCallback( flushWrites );
},
2000
);
}
}
};
}() );