includes/resourceloader/ResourceLoaderModule.php

   1 <?php
   2 /**
   3  * Abstraction for ResourceLoader modules.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @author Trevor Parscal
  22  * @author Roan Kattouw
  23  */
  24
  25 use MediaWiki\MediaWikiServices;
  26 use Psr\Log\LoggerAwareInterface;
  27 use Psr\Log\LoggerInterface;
  28 use Psr\Log\NullLogger;
  29 use Wikimedia\ScopedCallback;
  30
  31 /**
  32  * Abstraction for ResourceLoader modules, with name registration and maxage functionality.
  33  */
  34 abstract class ResourceLoaderModule implements LoggerAwareInterface {
  35         # Type of resource
  36         const TYPE_SCRIPTS = 'scripts';
  37         const TYPE_STYLES = 'styles';
  38         const TYPE_COMBINED = 'combined';
  39
  40         # Desired load type
  41         // Module only has styles (loaded via <style> or <link rel=stylesheet>)
  42         const LOAD_STYLES = 'styles';
  43         // Module may have other resources (loaded via mw.loader from a script)
  44         const LOAD_GENERAL = 'general';
  45
  46         # sitewide core module like a skin file or jQuery component
  47         const ORIGIN_CORE_SITEWIDE = 1;
  48
  49         # per-user module generated by the software
  50         const ORIGIN_CORE_INDIVIDUAL = 2;
  51
  52         # sitewide module generated from user-editable files, like MediaWiki:Common.js, or
  53         # modules accessible to multiple users, such as those generated by the Gadgets extension.
  54         const ORIGIN_USER_SITEWIDE = 3;
  55
  56         # per-user module generated from user-editable files, like User:Me/vector.js
  57         const ORIGIN_USER_INDIVIDUAL = 4;
  58
  59         # an access constant; make sure this is kept as the largest number in this group
  60         const ORIGIN_ALL = 10;
  61
  62         # script and style modules form a hierarchy of trustworthiness, with core modules like
  63         # skins and jQuery as most trustworthy, and user scripts as least trustworthy.  We can
  64         # limit the types of scripts and styles we allow to load on, say, sensitive special
  65         # pages like Special:UserLogin and Special:Preferences
  66         protected $origin = self::ORIGIN_CORE_SITEWIDE;
  67
  68         /* Protected Members */
  69
  70         protected $name = null;
  71         protected $targets = [ 'desktop' ];
  72
  73         // In-object cache for file dependencies
  74         protected $fileDeps = [];
  75         // In-object cache for message blob (keyed by language)
  76         protected $msgBlobs = [];
  77         // In-object cache for version hash
  78         protected $versionHash = [];
  79         // In-object cache for module content
  80         protected $contents = [];
  81
  82         /**
  83          * @var Config
  84          */
  85         protected $config;
  86
  87         /**
  88          * @var array|bool
  89          */
  90         protected $deprecated = false;
  91
  92         /**
  93          * @var LoggerInterface
  94          */
  95         protected $logger;
  96
  97         /* Methods */
  98
  99         /**
 100          * Get this module's name. This is set when the module is registered
 101          * with ResourceLoader::register()
 102          *
 103          * @return string|null Name (string) or null if no name was set
 104          */
 105         public function getName() {
 106                 return $this->name;
 107         }
 108
 109         /**
 110          * Set this module's name. This is called by ResourceLoader::register()
 111          * when registering the module. Other code should not call this.
 112          *
 113          * @param string $name Name
 114          */
 115         public function setName( $name ) {
 116                 $this->name = $name;
 117         }
 118
 119         /**
 120          * Get this module's origin. This is set when the module is registered
 121          * with ResourceLoader::register()
 122          *
 123          * @return int ResourceLoaderModule class constant, the subclass default
 124          *     if not set manually
 125          */
 126         public function getOrigin() {
 127                 return $this->origin;
 128         }
 129
 130         /**
 131          * @param ResourceLoaderContext $context
 132          * @return bool
 133          */
 134         public function getFlip( $context ) {
 135                 global $wgContLang;
 136
 137                 return $wgContLang->getDir() !== $context->getDirection();
 138         }
 139
 140         /**
 141          * Get JS representing deprecation information for the current module if available
 142          *
 143          * @return string JavaScript code
 144          */
 145         protected function getDeprecationInformation() {
 146                 $deprecationInfo = $this->deprecated;
 147                 if ( $deprecationInfo ) {
 148                         $name = $this->getName();
 149                         $warning = 'This page is using the deprecated ResourceLoader module "' . $name . '".';
 150                         if ( is_string( $deprecationInfo ) ) {
 151                                 $warning .= "\n" . $deprecationInfo;
 152                         }
 153                         return Xml::encodeJsCall(
 154                                 'mw.log.warn',
 155                                 [ $warning ]
 156                         );
 157                 } else {
 158                         return '';
 159                 }
 160         }
 161
 162         /**
 163          * Get all JS for this module for a given language and skin.
 164          * Includes all relevant JS except loader scripts.
 165          *
 166          * @param ResourceLoaderContext $context
 167          * @return string JavaScript code
 168          */
 169         public function getScript( ResourceLoaderContext $context ) {
 170                 // Stub, override expected
 171                 return '';
 172         }
 173
 174         /**
 175          * Takes named templates by the module and returns an array mapping.
 176          *
 177          * @return array of templates mapping template alias to content
 178          */
 179         public function getTemplates() {
 180                 // Stub, override expected.
 181                 return [];
 182         }
 183
 184         /**
 185          * @return Config
 186          * @since 1.24
 187          */
 188         public function getConfig() {
 189                 if ( $this->config === null ) {
 190                         // Ugh, fall back to default
 191                         $this->config = MediaWikiServices::getInstance()->getMainConfig();
 192                 }
 193
 194                 return $this->config;
 195         }
 196
 197         /**
 198          * @param Config $config
 199          * @since 1.24
 200          */
 201         public function setConfig( Config $config ) {
 202                 $this->config = $config;
 203         }
 204
 205         /**
 206          * @since 1.27
 207          * @param LoggerInterface $logger
 208          * @return null
 209          */
 210         public function setLogger( LoggerInterface $logger ) {
 211                 $this->logger = $logger;
 212         }
 213
 214         /**
 215          * @since 1.27
 216          * @return LoggerInterface
 217          */
 218         protected function getLogger() {
 219                 if ( !$this->logger ) {
 220                         $this->logger = new NullLogger();
 221                 }
 222                 return $this->logger;
 223         }
 224
 225         /**
 226          * Get the URL or URLs to load for this module's JS in debug mode.
 227          * The default behavior is to return a load.php?only=scripts URL for
 228          * the module, but file-based modules will want to override this to
 229          * load the files directly.
 230          *
 231          * This function is called only when 1) we're in debug mode, 2) there
 232          * is no only= parameter and 3) supportsURLLoading() returns true.
 233          * #2 is important to prevent an infinite loop, therefore this function
 234          * MUST return either an only= URL or a non-load.php URL.
 235          *
 236          * @param ResourceLoaderContext $context
 237          * @return array Array of URLs
 238          */
 239         public function getScriptURLsForDebug( ResourceLoaderContext $context ) {
 240                 $resourceLoader = $context->getResourceLoader();
 241                 $derivative = new DerivativeResourceLoaderContext( $context );
 242                 $derivative->setModules( [ $this->getName() ] );
 243                 $derivative->setOnly( 'scripts' );
 244                 $derivative->setDebug( true );
 245
 246                 $url = $resourceLoader->createLoaderURL(
 247                         $this->getSource(),
 248                         $derivative
 249                 );
 250
 251                 return [ $url ];
 252         }
 253
 254         /**
 255          * Whether this module supports URL loading. If this function returns false,
 256          * getScript() will be used even in cases (debug mode, no only param) where
 257          * getScriptURLsForDebug() would normally be used instead.
 258          * @return bool
 259          */
 260         public function supportsURLLoading() {
 261                 return true;
 262         }
 263
 264         /**
 265          * Get all CSS for this module for a given skin.
 266          *
 267          * @param ResourceLoaderContext $context
 268          * @return array List of CSS strings or array of CSS strings keyed by media type.
 269          *  like [ 'screen' => '.foo { width: 0 }' ];
 270          *  or [ 'screen' => [ '.foo { width: 0 }' ] ];
 271          */
 272         public function getStyles( ResourceLoaderContext $context ) {
 273                 // Stub, override expected
 274                 return [];
 275         }
 276
 277         /**
 278          * Get the URL or URLs to load for this module's CSS in debug mode.
 279          * The default behavior is to return a load.php?only=styles URL for
 280          * the module, but file-based modules will want to override this to
 281          * load the files directly. See also getScriptURLsForDebug()
 282          *
 283          * @param ResourceLoaderContext $context
 284          * @return array [ mediaType => [ URL1, URL2, ... ], ... ]
 285          */
 286         public function getStyleURLsForDebug( ResourceLoaderContext $context ) {
 287                 $resourceLoader = $context->getResourceLoader();
 288                 $derivative = new DerivativeResourceLoaderContext( $context );
 289                 $derivative->setModules( [ $this->getName() ] );
 290                 $derivative->setOnly( 'styles' );
 291                 $derivative->setDebug( true );
 292
 293                 $url = $resourceLoader->createLoaderURL(
 294                         $this->getSource(),
 295                         $derivative
 296                 );
 297
 298                 return [ 'all' => [ $url ] ];
 299         }
 300
 301         /**
 302          * Get the messages needed for this module.
 303          *
 304          * To get a JSON blob with messages, use MessageBlobStore::get()
 305          *
 306          * @return array List of message keys. Keys may occur more than once
 307          */
 308         public function getMessages() {
 309                 // Stub, override expected
 310                 return [];
 311         }
 312
 313         /**
 314          * Get the group this module is in.
 315          *
 316          * @return string Group name
 317          */
 318         public function getGroup() {
 319                 // Stub, override expected
 320                 return null;
 321         }
 322
 323         /**
 324          * Get the origin of this module. Should only be overridden for foreign modules.
 325          *
 326          * @return string Origin name, 'local' for local modules
 327          */
 328         public function getSource() {
 329                 // Stub, override expected
 330                 return 'local';
 331         }
 332
 333         /**
 334          * From where in the page HTML should this module be loaded?
 335          *
 336          * @deprecated since 1.29 Obsolete. All modules load async from `<head>`.
 337          * @return string
 338          */
 339         public function getPosition() {
 340                 return 'top';
 341         }
 342
 343         /**
 344          * Whether this module's JS expects to work without the client-side ResourceLoader module.
 345          * Returning true from this function will prevent mw.loader.state() call from being
 346          * appended to the bottom of the script.
 347          *
 348          * @return bool
 349          */
 350         public function isRaw() {
 351                 return false;
 352         }
 353
 354         /**
 355          * Get a list of modules this module depends on.
 356          *
 357          * Dependency information is taken into account when loading a module
 358          * on the client side.
 359          *
 360          * Note: It is expected that $context will be made non-optional in the near
 361          * future.
 362          *
 363          * @param ResourceLoaderContext $context
 364          * @return array List of module names as strings
 365          */
 366         public function getDependencies( ResourceLoaderContext $context = null ) {
 367                 // Stub, override expected
 368                 return [];
 369         }
 370
 371         /**
 372          * Get target(s) for the module, eg ['desktop'] or ['desktop', 'mobile']
 373          *
 374          * @return array Array of strings
 375          */
 376         public function getTargets() {
 377                 return $this->targets;
 378         }
 379
 380         /**
 381          * Get the module's load type.
 382          *
 383          * @since 1.28
 384          * @return string ResourceLoaderModule LOAD_* constant
 385          */
 386         public function getType() {
 387                 return self::LOAD_GENERAL;
 388         }
 389
 390         /**
 391          * Get the skip function.
 392          *
 393          * Modules that provide fallback functionality can provide a "skip function". This
 394          * function, if provided, will be passed along to the module registry on the client.
 395          * When this module is loaded (either directly or as a dependency of another module),
 396          * then this function is executed first. If the function returns true, the module will
 397          * instantly be considered "ready" without requesting the associated module resources.
 398          *
 399          * The value returned here must be valid javascript for execution in a private function.
 400          * It must not contain the "function () {" and "}" wrapper though.
 401          *
 402          * @return string|null A JavaScript function body returning a boolean value, or null
 403          */
 404         public function getSkipFunction() {
 405                 return null;
 406         }
 407
 408         /**
 409          * Get the files this module depends on indirectly for a given skin.
 410          *
 411          * These are only image files referenced by the module's stylesheet.
 412          *
 413          * @param ResourceLoaderContext $context
 414          * @return array List of files
 415          */
 416         protected function getFileDependencies( ResourceLoaderContext $context ) {
 417                 $vary = $context->getSkin() . '|' . $context->getLanguage();
 418
 419                 // Try in-object cache first
 420                 if ( !isset( $this->fileDeps[$vary] ) ) {
 421                         $dbr = wfGetDB( DB_REPLICA );
 422                         $deps = $dbr->selectField( 'module_deps',
 423                                 'md_deps',
 424                                 [
 425                                         'md_module' => $this->getName(),
 426                                         'md_skin' => $vary,
 427                                 ],
 428                                 __METHOD__
 429                         );
 430
 431                         if ( !is_null( $deps ) ) {
 432                                 $this->fileDeps[$vary] = self::expandRelativePaths(
 433                                         (array)FormatJson::decode( $deps, true )
 434                                 );
 435                         } else {
 436                                 $this->fileDeps[$vary] = [];
 437                         }
 438                 }
 439                 return $this->fileDeps[$vary];
 440         }
 441
 442         /**
 443          * Set in-object cache for file dependencies.
 444          *
 445          * This is used to retrieve data in batches. See ResourceLoader::preloadModuleInfo().
 446          * To save the data, use saveFileDependencies().
 447          *
 448          * @param ResourceLoaderContext $context
 449          * @param string[] $files Array of file names
 450          */
 451         public function setFileDependencies( ResourceLoaderContext $context, $files ) {
 452                 $vary = $context->getSkin() . '|' . $context->getLanguage();
 453                 $this->fileDeps[$vary] = $files;
 454         }
 455
 456         /**
 457          * Set the files this module depends on indirectly for a given skin.
 458          *
 459          * @since 1.27
 460          * @param ResourceLoaderContext $context
 461          * @param array $localFileRefs List of files
 462          */
 463         protected function saveFileDependencies( ResourceLoaderContext $context, $localFileRefs ) {
 464
 465                 try {
 466                         // Related bugs and performance considerations:
 467                         // 1. Don't needlessly change the database value with the same list in a
 468                         //    different order or with duplicates.
 469                         // 2. Use relative paths to avoid ghost entries when $IP changes. (T111481)
 470                         // 3. Don't needlessly replace the database with the same value
 471                         //    just because $IP changed (e.g. when upgrading a wiki).
 472                         // 4. Don't create an endless replace loop on every request for this
 473                         //    module when '../' is used anywhere. Even though both are expanded
 474                         //    (one expanded by getFileDependencies from the DB, the other is
 475                         //    still raw as originally read by RL), the latter has not
 476                         //    been normalized yet.
 477
 478                         // Normalise
 479                         $localFileRefs = array_values( array_unique( $localFileRefs ) );
 480                         sort( $localFileRefs );
 481                         $localPaths = self::getRelativePaths( $localFileRefs );
 482
 483                         $storedPaths = self::getRelativePaths( $this->getFileDependencies( $context ) );
 484                         // If the list has been modified since last time we cached it, update the cache
 485                         if ( $localPaths !== $storedPaths ) {
 486                                 $vary = $context->getSkin() . '|' . $context->getLanguage();
 487                                 $cache = ObjectCache::getLocalClusterInstance();
 488                                 $key = $cache->makeKey( __METHOD__, $this->getName(), $vary );
 489                                 $scopeLock = $cache->getScopedLock( $key, 0 );
 490                                 if ( !$scopeLock ) {
 491                                         return; // T124649; avoid write slams
 492                                 }
 493
 494                                 $deps = FormatJson::encode( $localPaths );
 495                                 $dbw = wfGetDB( DB_MASTER );
 496                                 $dbw->upsert( 'module_deps',
 497                                         [
 498                                                 'md_module' => $this->getName(),
 499                                                 'md_skin' => $vary,
 500                                                 'md_deps' => $deps,
 501                                         ],
 502                                         [ 'md_module', 'md_skin' ],
 503                                         [
 504                                                 'md_deps' => $deps,
 505                                         ]
 506                                 );
 507
 508                                 if ( $dbw->trxLevel() ) {
 509                                         $dbw->onTransactionResolution(
 510                                                 function () use ( &$scopeLock ) {
 511                                                         ScopedCallback::consume( $scopeLock ); // release after commit
 512                                                 },
 513                                                 __METHOD__
 514                                         );
 515                                 }
 516                         }
 517                 } catch ( Exception $e ) {
 518                         wfDebugLog( 'resourceloader', __METHOD__ . ": failed to update DB: $e" );
 519                 }
 520         }
 521
 522         /**
 523          * Make file paths relative to MediaWiki directory.
 524          *
 525          * This is used to make file paths safe for storing in a database without the paths
 526          * becoming stale or incorrect when MediaWiki is moved or upgraded (T111481).
 527          *
 528          * @since 1.27
 529          * @param array $filePaths
 530          * @return array
 531          */
 532         public static function getRelativePaths( array $filePaths ) {
 533                 global $IP;
 534                 return array_map( function ( $path ) use ( $IP ) {
 535                         return RelPath\getRelativePath( $path, $IP );
 536                 }, $filePaths );
 537         }
 538
 539         /**
 540          * Expand directories relative to $IP.
 541          *
 542          * @since 1.27
 543          * @param array $filePaths
 544          * @return array
 545          */
 546         public static function expandRelativePaths( array $filePaths ) {
 547                 global $IP;
 548                 return array_map( function ( $path ) use ( $IP ) {
 549                         return RelPath\joinPath( $IP, $path );
 550                 }, $filePaths );
 551         }
 552
 553         /**
 554          * Get the hash of the message blob.
 555          *
 556          * @since 1.27
 557          * @param ResourceLoaderContext $context
 558          * @return string|null JSON blob or null if module has no messages
 559          */
 560         protected function getMessageBlob( ResourceLoaderContext $context ) {
 561                 if ( !$this->getMessages() ) {
 562                         // Don't bother consulting MessageBlobStore
 563                         return null;
 564                 }
 565                 // Message blobs may only vary language, not by context keys
 566                 $lang = $context->getLanguage();
 567                 if ( !isset( $this->msgBlobs[$lang] ) ) {
 568                         $this->getLogger()->warning( 'Message blob for {module} should have been preloaded', [
 569                                 'module' => $this->getName(),
 570                         ] );
 571                         $store = $context->getResourceLoader()->getMessageBlobStore();
 572                         $this->msgBlobs[$lang] = $store->getBlob( $this, $lang );
 573                 }
 574                 return $this->msgBlobs[$lang];
 575         }
 576
 577         /**
 578          * Set in-object cache for message blobs.
 579          *
 580          * Used to allow fetching of message blobs in batches. See ResourceLoader::preloadModuleInfo().
 581          *
 582          * @since 1.27
 583          * @param string|null $blob JSON blob or null
 584          * @param string $lang Language code
 585          */
 586         public function setMessageBlob( $blob, $lang ) {
 587                 $this->msgBlobs[$lang] = $blob;
 588         }
 589
 590         /**
 591          * Get module-specific LESS variables, if any.
 592          *
 593          * @since 1.27
 594          * @param ResourceLoaderContext $context
 595          * @return array Module-specific LESS variables.
 596          */
 597         protected function getLessVars( ResourceLoaderContext $context ) {
 598                 return [];
 599         }
 600
 601         /**
 602          * Get an array of this module's resources. Ready for serving to the web.
 603          *
 604          * @since 1.26
 605          * @param ResourceLoaderContext $context
 606          * @return array
 607          */
 608         public function getModuleContent( ResourceLoaderContext $context ) {
 609                 $contextHash = $context->getHash();
 610                 // Cache this expensive operation. This calls builds the scripts, styles, and messages
 611                 // content which typically involves filesystem and/or database access.
 612                 if ( !array_key_exists( $contextHash, $this->contents ) ) {
 613                         $this->contents[$contextHash] = $this->buildContent( $context );
 614                 }
 615                 return $this->contents[$contextHash];
 616         }
 617
 618         /**
 619          * Bundle all resources attached to this module into an array.
 620          *
 621          * @since 1.26
 622          * @param ResourceLoaderContext $context
 623          * @return array
 624          */
 625         final protected function buildContent( ResourceLoaderContext $context ) {
 626                 $rl = $context->getResourceLoader();
 627                 $stats = MediaWikiServices::getInstance()->getStatsdDataFactory();
 628                 $statStart = microtime( true );
 629
 630                 // Only include properties that are relevant to this context (e.g. only=scripts)
 631                 // and that are non-empty (e.g. don't include "templates" for modules without
 632                 // templates). This helps prevent invalidating cache for all modules when new
 633                 // optional properties are introduced.
 634                 $content = [];
 635
 636                 // Scripts
 637                 if ( $context->shouldIncludeScripts() ) {
 638                         // If we are in debug mode, we'll want to return an array of URLs if possible
 639                         // However, we can't do this if the module doesn't support it
 640                         // We also can't do this if there is an only= parameter, because we have to give
 641                         // the module a way to return a load.php URL without causing an infinite loop
 642                         if ( $context->getDebug() && !$context->getOnly() && $this->supportsURLLoading() ) {
 643                                 $scripts = $this->getScriptURLsForDebug( $context );
 644                         } else {
 645                                 $scripts = $this->getScript( $context );
 646                                 // Make the script safe to concatenate by making sure there is at least one
 647                                 // trailing new line at the end of the content. Previously, this looked for
 648                                 // a semi-colon instead, but that breaks concatenation if the semicolon
 649                                 // is inside a comment like "// foo();". Instead, simply use a
 650                                 // line break as separator which matches JavaScript native logic for implicitly
 651                                 // ending statements even if a semi-colon is missing.
 652                                 // Bugs: T29054, T162719.
 653                                 if ( is_string( $scripts )
 654                                         && strlen( $scripts )
 655                                         && substr( $scripts, -1 ) !== "\n"
 656                                 ) {
 657                                         $scripts .= "\n";
 658                                 }
 659                         }
 660                         $content['scripts'] = $scripts;
 661                 }
 662
 663                 // Styles
 664                 if ( $context->shouldIncludeStyles() ) {
 665                         $styles = [];
 666                         // Don't create empty stylesheets like [ '' => '' ] for modules
 667                         // that don't *have* any stylesheets (T40024).
 668                         $stylePairs = $this->getStyles( $context );
 669                         if ( count( $stylePairs ) ) {
 670                                 // If we are in debug mode without &only= set, we'll want to return an array of URLs
 671                                 // See comment near shouldIncludeScripts() for more details
 672                                 if ( $context->getDebug() && !$context->getOnly() && $this->supportsURLLoading() ) {
 673                                         $styles = [
 674                                                 'url' => $this->getStyleURLsForDebug( $context )
 675                                         ];
 676                                 } else {
 677                                         // Minify CSS before embedding in mw.loader.implement call
 678                                         // (unless in debug mode)
 679                                         if ( !$context->getDebug() ) {
 680                                                 foreach ( $stylePairs as $media => $style ) {
 681                                                         // Can be either a string or an array of strings.
 682                                                         if ( is_array( $style ) ) {
 683                                                                 $stylePairs[$media] = [];
 684                                                                 foreach ( $style as $cssText ) {
 685                                                                         if ( is_string( $cssText ) ) {
 686                                                                                 $stylePairs[$media][] =
 687                                                                                         ResourceLoader::filter( 'minify-css', $cssText );
 688                                                                         }
 689                                                                 }
 690                                                         } elseif ( is_string( $style ) ) {
 691                                                                 $stylePairs[$media] = ResourceLoader::filter( 'minify-css', $style );
 692                                                         }
 693                                                 }
 694                                         }
 695                                         // Wrap styles into @media groups as needed and flatten into a numerical array
 696                                         $styles = [
 697                                                 'css' => $rl->makeCombinedStyles( $stylePairs )
 698                                         ];
 699                                 }
 700                         }
 701                         $content['styles'] = $styles;
 702                 }
 703
 704                 // Messages
 705                 $blob = $this->getMessageBlob( $context );
 706                 if ( $blob ) {
 707                         $content['messagesBlob'] = $blob;
 708                 }
 709
 710                 $templates = $this->getTemplates();
 711                 if ( $templates ) {
 712                         $content['templates'] = $templates;
 713                 }
 714
 715                 $statTiming = microtime( true ) - $statStart;
 716                 $statName = strtr( $this->getName(), '.', '_' );
 717                 $stats->timing( "resourceloader_build.all", 1000 * $statTiming );
 718                 $stats->timing( "resourceloader_build.$statName", 1000 * $statTiming );
 719
 720                 return $content;
 721         }
 722
 723         /**
 724          * Get a string identifying the current version of this module in a given context.
 725          *
 726          * Whenever anything happens that changes the module's response (e.g. scripts, styles, and
 727          * messages) this value must change. This value is used to store module responses in cache.
 728          * (Both client-side and server-side.)
 729          *
 730          * It is not recommended to override this directly. Use getDefinitionSummary() instead.
 731          * If overridden, one must call the parent getVersionHash(), append data and re-hash.
 732          *
 733          * This method should be quick because it is frequently run by ResourceLoaderStartUpModule to
 734          * propagate changes to the client and effectively invalidate cache.
 735          *
 736          * For backward-compatibility, the following optional data providers are automatically included:
 737          *
 738          * - getModifiedTime()
 739          * - getModifiedHash()
 740          *
 741          * @since 1.26
 742          * @param ResourceLoaderContext $context
 743          * @return string Hash (should use ResourceLoader::makeHash)
 744          */
 745         public function getVersionHash( ResourceLoaderContext $context ) {
 746                 // The startup module produces a manifest with versions representing the entire module.
 747                 // Typically, the request for the startup module itself has only=scripts. That must apply
 748                 // only to the startup module content, and not to the module version computed here.
 749                 $context = new DerivativeResourceLoaderContext( $context );
 750                 $context->setModules( [] );
 751                 // Version hash must cover all resources, regardless of startup request itself.
 752                 $context->setOnly( null );
 753                 // Compute version hash based on content, not debug urls.
 754                 $context->setDebug( false );
 755
 756                 // Cache this somewhat expensive operation. Especially because some classes
 757                 // (e.g. startup module) iterate more than once over all modules to get versions.
 758                 $contextHash = $context->getHash();
 759                 if ( !array_key_exists( $contextHash, $this->versionHash ) ) {
 760
 761                         if ( $this->enableModuleContentVersion() ) {
 762                                 // Detect changes directly
 763                                 $str = json_encode( $this->getModuleContent( $context ) );
 764                         } else {
 765                                 // Infer changes based on definition and other metrics
 766                                 $summary = $this->getDefinitionSummary( $context );
 767                                 if ( !isset( $summary['_cacheEpoch'] ) ) {
 768                                         throw new LogicException( 'getDefinitionSummary must call parent method' );
 769                                 }
 770                                 $str = json_encode( $summary );
 771
 772                                 $mtime = $this->getModifiedTime( $context );
 773                                 if ( $mtime !== null ) {
 774                                         // Support: MediaWiki 1.25 and earlier
 775                                         $str .= strval( $mtime );
 776                                 }
 777
 778                                 $mhash = $this->getModifiedHash( $context );
 779                                 if ( $mhash !== null ) {
 780                                         // Support: MediaWiki 1.25 and earlier
 781                                         $str .= strval( $mhash );
 782                                 }
 783                         }
 784
 785                         $this->versionHash[$contextHash] = ResourceLoader::makeHash( $str );
 786                 }
 787                 return $this->versionHash[$contextHash];
 788         }
 789
 790         /**
 791          * Whether to generate version hash based on module content.
 792          *
 793          * If a module requires database or file system access to build the module
 794          * content, consider disabling this in favour of manually tracking relevant
 795          * aspects in getDefinitionSummary(). See getVersionHash() for how this is used.
 796          *
 797          * @return bool
 798          */
 799         public function enableModuleContentVersion() {
 800                 return false;
 801         }
 802
 803         /**
 804          * Get the definition summary for this module.
 805          *
 806          * This is the method subclasses are recommended to use to track values in their
 807          * version hash. Call this in getVersionHash() and pass it to e.g. json_encode.
 808          *
 809          * Subclasses must call the parent getDefinitionSummary() and build on that.
 810          * It is recommended that each subclass appends its own new array. This prevents
 811          * clashes or accidental overwrites of existing keys and gives each subclass
 812          * its own scope for simple array keys.
 813          *
 814          * @code
 815          *     $summary = parent::getDefinitionSummary( $context );
 816          *     $summary[] = [
 817          *         'foo' => 123,
 818          *         'bar' => 'quux',
 819          *     ];
 820          *     return $summary;
 821          * @endcode
 822          *
 823          * Return an array containing values from all significant properties of this
 824          * module's definition.
 825          *
 826          * Be careful not to normalise too much. Especially preserve the order of things
 827          * that carry significance in getScript and getStyles (T39812).
 828          *
 829          * Avoid including things that are insiginificant (e.g. order of message keys is
 830          * insignificant and should be sorted to avoid unnecessary cache invalidation).
 831          *
 832          * This data structure must exclusively contain arrays and scalars as values (avoid
 833          * object instances) to allow simple serialisation using json_encode.
 834          *
 835          * If modules have a hash or timestamp from another source, that may be incuded as-is.
 836          *
 837          * A number of utility methods are available to help you gather data. These are not
 838          * called by default and must be included by the subclass' getDefinitionSummary().
 839          *
 840          * - getMessageBlob()
 841          *
 842          * @since 1.23
 843          * @param ResourceLoaderContext $context
 844          * @return array|null
 845          */
 846         public function getDefinitionSummary( ResourceLoaderContext $context ) {
 847                 return [
 848                         '_class' => static::class,
 849                         '_cacheEpoch' => $this->getConfig()->get( 'CacheEpoch' ),
 850                 ];
 851         }
 852
 853         /**
 854          * Get this module's last modification timestamp for a given context.
 855          *
 856          * @deprecated since 1.26 Use getDefinitionSummary() instead
 857          * @param ResourceLoaderContext $context Context object
 858          * @return int|null UNIX timestamp
 859          */
 860         public function getModifiedTime( ResourceLoaderContext $context ) {
 861                 return null;
 862         }
 863
 864         /**
 865          * Helper method for providing a version hash to getVersionHash().
 866          *
 867          * @deprecated since 1.26 Use getDefinitionSummary() instead
 868          * @param ResourceLoaderContext $context
 869          * @return string|null Hash
 870          */
 871         public function getModifiedHash( ResourceLoaderContext $context ) {
 872                 return null;
 873         }
 874
 875         /**
 876          * Back-compat dummy for old subclass implementations of getModifiedTime().
 877          *
 878          * This method used to use ObjectCache to track when a hash was first seen. That principle
 879          * stems from a time that ResourceLoader could only identify module versions by timestamp.
 880          * That is no longer the case. Use getDefinitionSummary() directly.
 881          *
 882          * @deprecated since 1.26 Superseded by getVersionHash()
 883          * @param ResourceLoaderContext $context
 884          * @return int UNIX timestamp
 885          */
 886         public function getHashMtime( ResourceLoaderContext $context ) {
 887                 if ( !is_string( $this->getModifiedHash( $context ) ) ) {
 888                         return 1;
 889                 }
 890                 // Dummy that is > 1
 891                 return 2;
 892         }
 893
 894         /**
 895          * Back-compat dummy for old subclass implementations of getModifiedTime().
 896          *
 897          * @since 1.23
 898          * @deprecated since 1.26 Superseded by getVersionHash()
 899          * @param ResourceLoaderContext $context
 900          * @return int UNIX timestamp
 901          */
 902         public function getDefinitionMtime( ResourceLoaderContext $context ) {
 903                 if ( $this->getDefinitionSummary( $context ) === null ) {
 904                         return 1;
 905                 }
 906                 // Dummy that is > 1
 907                 return 2;
 908         }
 909
 910         /**
 911          * Check whether this module is known to be empty. If a child class
 912          * has an easy and cheap way to determine that this module is
 913          * definitely going to be empty, it should override this method to
 914          * return true in that case. Callers may optimize the request for this
 915          * module away if this function returns true.
 916          * @param ResourceLoaderContext $context
 917          * @return bool
 918          */
 919         public function isKnownEmpty( ResourceLoaderContext $context ) {
 920                 return false;
 921         }
 922
 923         /** @var JSParser Lazy-initialized; use self::javaScriptParser() */
 924         private static $jsParser;
 925         private static $parseCacheVersion = 1;
 926
 927         /**
 928          * Validate a given script file; if valid returns the original source.
 929          * If invalid, returns replacement JS source that throws an exception.
 930          *
 931          * @param string $fileName
 932          * @param string $contents
 933          * @return string JS with the original, or a replacement error
 934          */
 935         protected function validateScriptFile( $fileName, $contents ) {
 936                 if ( !$this->getConfig()->get( 'ResourceLoaderValidateJS' ) ) {
 937                         return $contents;
 938                 }
 939                 $cache = ObjectCache::getMainWANInstance();
 940                 return $cache->getWithSetCallback(
 941                         $cache->makeGlobalKey(
 942                                 'resourceloader',
 943                                 'jsparse',
 944                                 self::$parseCacheVersion,
 945                                 md5( $contents ),
 946                                 $fileName
 947                         ),
 948                         $cache::TTL_WEEK,
 949                         function () use ( $contents, $fileName ) {
 950                                 $parser = self::javaScriptParser();
 951                                 try {
 952                                         $parser->parse( $contents, $fileName, 1 );
 953                                         $result = $contents;
 954                                 } catch ( Exception $e ) {
 955                                         // We'll save this to cache to avoid having to re-validate broken JS
 956                                         $err = $e->getMessage();
 957                                         $result = "mw.log.error(" .
 958                                                 Xml::encodeJsVar( "JavaScript parse error: $err" ) . ");";
 959                                 }
 960                                 return $result;
 961                         }
 962                 );
 963         }
 964
 965         /**
 966          * @return JSParser
 967          */
 968         protected static function javaScriptParser() {
 969                 if ( !self::$jsParser ) {
 970                         self::$jsParser = new JSParser();
 971                 }
 972                 return self::$jsParser;
 973         }
 974
 975         /**
 976          * Safe version of filemtime(), which doesn't throw a PHP warning if the file doesn't exist.
 977          * Defaults to 1.
 978          *
 979          * @param string $filePath File path
 980          * @return int UNIX timestamp
 981          */
 982         protected static function safeFilemtime( $filePath ) {
 983                 MediaWiki\suppressWarnings();
 984                 $mtime = filemtime( $filePath ) ?: 1;
 985                 MediaWiki\restoreWarnings();
 986                 return $mtime;
 987         }
 988
 989         /**
 990          * Compute a non-cryptographic string hash of a file's contents.
 991          * If the file does not exist or cannot be read, returns an empty string.
 992          *
 993          * @since 1.26 Uses MD4 instead of SHA1.
 994          * @param string $filePath File path
 995          * @return string Hash
 996          */
 997         protected static function safeFileHash( $filePath ) {
 998                 return FileContentsHasher::getFileContentsHash( $filePath );
 999         }
1000 }