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 Psr\Log\LoggerAwareInterface;
  26 use Psr\Log\LoggerInterface;
  27 use Psr\Log\NullLogger;
  28
  29 /**
  30  * Abstraction for ResourceLoader modules, with name registration and maxage functionality.
  31  */
  32 abstract class ResourceLoaderModule implements LoggerAwareInterface {
  33         # Type of resource
  34         const TYPE_SCRIPTS = 'scripts';
  35         const TYPE_STYLES = 'styles';
  36         const TYPE_COMBINED = 'combined';
  37
  38         # sitewide core module like a skin file or jQuery component
  39         const ORIGIN_CORE_SITEWIDE = 1;
  40
  41         # per-user module generated by the software
  42         const ORIGIN_CORE_INDIVIDUAL = 2;
  43
  44         # sitewide module generated from user-editable files, like MediaWiki:Common.js, or
  45         # modules accessible to multiple users, such as those generated by the Gadgets extension.
  46         const ORIGIN_USER_SITEWIDE = 3;
  47
  48         # per-user module generated from user-editable files, like User:Me/vector.js
  49         const ORIGIN_USER_INDIVIDUAL = 4;
  50
  51         # an access constant; make sure this is kept as the largest number in this group
  52         const ORIGIN_ALL = 10;
  53
  54         # script and style modules form a hierarchy of trustworthiness, with core modules like
  55         # skins and jQuery as most trustworthy, and user scripts as least trustworthy.  We can
  56         # limit the types of scripts and styles we allow to load on, say, sensitive special
  57         # pages like Special:UserLogin and Special:Preferences
  58         protected $origin = self::ORIGIN_CORE_SITEWIDE;
  59
  60         /* Protected Members */
  61
  62         protected $name = null;
  63         protected $targets = array( 'desktop' );
  64
  65         // In-object cache for file dependencies
  66         protected $fileDeps = array();
  67         // In-object cache for message blob (keyed by language)
  68         protected $msgBlobs = array();
  69         // In-object cache for version hash
  70         protected $versionHash = array();
  71         // In-object cache for module content
  72         protected $contents = array();
  73
  74         /**
  75          * @var Config
  76          */
  77         protected $config;
  78
  79         /**
  80          * @var LoggerInterface
  81          */
  82         protected $logger;
  83
  84         /* Methods */
  85
  86         /**
  87          * Get this module's name. This is set when the module is registered
  88          * with ResourceLoader::register()
  89          *
  90          * @return string|null Name (string) or null if no name was set
  91          */
  92         public function getName() {
  93                 return $this->name;
  94         }
  95
  96         /**
  97          * Set this module's name. This is called by ResourceLoader::register()
  98          * when registering the module. Other code should not call this.
  99          *
 100          * @param string $name Name
 101          */
 102         public function setName( $name ) {
 103                 $this->name = $name;
 104         }
 105
 106         /**
 107          * Get this module's origin. This is set when the module is registered
 108          * with ResourceLoader::register()
 109          *
 110          * @return int ResourceLoaderModule class constant, the subclass default
 111          *     if not set manually
 112          */
 113         public function getOrigin() {
 114                 return $this->origin;
 115         }
 116
 117         /**
 118          * Set this module's origin. This is called by ResourceLoader::register()
 119          * when registering the module. Other code should not call this.
 120          *
 121          * @param int $origin Origin
 122          */
 123         public function setOrigin( $origin ) {
 124                 $this->origin = $origin;
 125         }
 126
 127         /**
 128          * @param ResourceLoaderContext $context
 129          * @return bool
 130          */
 131         public function getFlip( $context ) {
 132                 global $wgContLang;
 133
 134                 return $wgContLang->getDir() !== $context->getDirection();
 135         }
 136
 137         /**
 138          * Get all JS for this module for a given language and skin.
 139          * Includes all relevant JS except loader scripts.
 140          *
 141          * @param ResourceLoaderContext $context
 142          * @return string JavaScript code
 143          */
 144         public function getScript( ResourceLoaderContext $context ) {
 145                 // Stub, override expected
 146                 return '';
 147         }
 148
 149         /**
 150          * Takes named templates by the module and returns an array mapping.
 151          *
 152          * @return array of templates mapping template alias to content
 153          */
 154         public function getTemplates() {
 155                 // Stub, override expected.
 156                 return array();
 157         }
 158
 159         /**
 160          * @return Config
 161          * @since 1.24
 162          */
 163         public function getConfig() {
 164                 if ( $this->config === null ) {
 165                         // Ugh, fall back to default
 166                         $this->config = ConfigFactory::getDefaultInstance()->makeConfig( 'main' );
 167                 }
 168
 169                 return $this->config;
 170         }
 171
 172         /**
 173          * @param Config $config
 174          * @since 1.24
 175          */
 176         public function setConfig( Config $config ) {
 177                 $this->config = $config;
 178         }
 179
 180         /**
 181          * @since 1.27
 182          * @param LoggerInterface $logger
 183          * @return null
 184          */
 185         public function setLogger( LoggerInterface $logger ) {
 186                 $this->logger = $logger;
 187         }
 188
 189         /**
 190          * @since 1.27
 191          * @return LoggerInterface
 192          */
 193         protected function getLogger() {
 194                 if ( !$this->logger ) {
 195                         $this->logger = new NullLogger();
 196                 }
 197                 return $this->logger;
 198         }
 199
 200         /**
 201          * Get the URL or URLs to load for this module's JS in debug mode.
 202          * The default behavior is to return a load.php?only=scripts URL for
 203          * the module, but file-based modules will want to override this to
 204          * load the files directly.
 205          *
 206          * This function is called only when 1) we're in debug mode, 2) there
 207          * is no only= parameter and 3) supportsURLLoading() returns true.
 208          * #2 is important to prevent an infinite loop, therefore this function
 209          * MUST return either an only= URL or a non-load.php URL.
 210          *
 211          * @param ResourceLoaderContext $context
 212          * @return array Array of URLs
 213          */
 214         public function getScriptURLsForDebug( ResourceLoaderContext $context ) {
 215                 $resourceLoader = $context->getResourceLoader();
 216                 $derivative = new DerivativeResourceLoaderContext( $context );
 217                 $derivative->setModules( array( $this->getName() ) );
 218                 $derivative->setOnly( 'scripts' );
 219                 $derivative->setDebug( true );
 220
 221                 $url = $resourceLoader->createLoaderURL(
 222                         $this->getSource(),
 223                         $derivative
 224                 );
 225
 226                 return array( $url );
 227         }
 228
 229         /**
 230          * Whether this module supports URL loading. If this function returns false,
 231          * getScript() will be used even in cases (debug mode, no only param) where
 232          * getScriptURLsForDebug() would normally be used instead.
 233          * @return bool
 234          */
 235         public function supportsURLLoading() {
 236                 return true;
 237         }
 238
 239         /**
 240          * Get all CSS for this module for a given skin.
 241          *
 242          * @param ResourceLoaderContext $context
 243          * @return array List of CSS strings or array of CSS strings keyed by media type.
 244          *  like array( 'screen' => '.foo { width: 0 }' );
 245          *  or array( 'screen' => array( '.foo { width: 0 }' ) );
 246          */
 247         public function getStyles( ResourceLoaderContext $context ) {
 248                 // Stub, override expected
 249                 return array();
 250         }
 251
 252         /**
 253          * Get the URL or URLs to load for this module's CSS in debug mode.
 254          * The default behavior is to return a load.php?only=styles URL for
 255          * the module, but file-based modules will want to override this to
 256          * load the files directly. See also getScriptURLsForDebug()
 257          *
 258          * @param ResourceLoaderContext $context
 259          * @return array Array( mediaType => array( URL1, URL2, ... ), ... )
 260          */
 261         public function getStyleURLsForDebug( ResourceLoaderContext $context ) {
 262                 $resourceLoader = $context->getResourceLoader();
 263                 $derivative = new DerivativeResourceLoaderContext( $context );
 264                 $derivative->setModules( array( $this->getName() ) );
 265                 $derivative->setOnly( 'styles' );
 266                 $derivative->setDebug( true );
 267
 268                 $url = $resourceLoader->createLoaderURL(
 269                         $this->getSource(),
 270                         $derivative
 271                 );
 272
 273                 return array( 'all' => array( $url ) );
 274         }
 275
 276         /**
 277          * Get the messages needed for this module.
 278          *
 279          * To get a JSON blob with messages, use MessageBlobStore::get()
 280          *
 281          * @return array List of message keys. Keys may occur more than once
 282          */
 283         public function getMessages() {
 284                 // Stub, override expected
 285                 return array();
 286         }
 287
 288         /**
 289          * Get the group this module is in.
 290          *
 291          * @return string Group name
 292          */
 293         public function getGroup() {
 294                 // Stub, override expected
 295                 return null;
 296         }
 297
 298         /**
 299          * Get the origin of this module. Should only be overridden for foreign modules.
 300          *
 301          * @return string Origin name, 'local' for local modules
 302          */
 303         public function getSource() {
 304                 // Stub, override expected
 305                 return 'local';
 306         }
 307
 308         /**
 309          * Where on the HTML page should this module's JS be loaded?
 310          *  - 'top': in the "<head>"
 311          *  - 'bottom': at the bottom of the "<body>"
 312          *
 313          * @return string
 314          */
 315         public function getPosition() {
 316                 return 'bottom';
 317         }
 318
 319         /**
 320          * Whether this module's JS expects to work without the client-side ResourceLoader module.
 321          * Returning true from this function will prevent mw.loader.state() call from being
 322          * appended to the bottom of the script.
 323          *
 324          * @return bool
 325          */
 326         public function isRaw() {
 327                 return false;
 328         }
 329
 330         /**
 331          * Get a list of modules this module depends on.
 332          *
 333          * Dependency information is taken into account when loading a module
 334          * on the client side.
 335          *
 336          * Note: It is expected that $context will be made non-optional in the near
 337          * future.
 338          *
 339          * @param ResourceLoaderContext $context
 340          * @return array List of module names as strings
 341          */
 342         public function getDependencies( ResourceLoaderContext $context = null ) {
 343                 // Stub, override expected
 344                 return array();
 345         }
 346
 347         /**
 348          * Get target(s) for the module, eg ['desktop'] or ['desktop', 'mobile']
 349          *
 350          * @return array Array of strings
 351          */
 352         public function getTargets() {
 353                 return $this->targets;
 354         }
 355
 356         /**
 357          * Get the skip function.
 358          *
 359          * Modules that provide fallback functionality can provide a "skip function". This
 360          * function, if provided, will be passed along to the module registry on the client.
 361          * When this module is loaded (either directly or as a dependency of another module),
 362          * then this function is executed first. If the function returns true, the module will
 363          * instantly be considered "ready" without requesting the associated module resources.
 364          *
 365          * The value returned here must be valid javascript for execution in a private function.
 366          * It must not contain the "function () {" and "}" wrapper though.
 367          *
 368          * @return string|null A JavaScript function body returning a boolean value, or null
 369          */
 370         public function getSkipFunction() {
 371                 return null;
 372         }
 373
 374         /**
 375          * Get the files this module depends on indirectly for a given skin.
 376          *
 377          * These are only image files referenced by the module's stylesheet.
 378          *
 379          * @param ResourceLoaderContext $context
 380          * @return array List of files
 381          */
 382         protected function getFileDependencies( ResourceLoaderContext $context ) {
 383                 $vary = $context->getSkin() . '|' . $context->getLanguage();
 384
 385                 // Try in-object cache first
 386                 if ( !isset( $this->fileDeps[$vary] ) ) {
 387                         $dbr = wfGetDB( DB_SLAVE );
 388                         $deps = $dbr->selectField( 'module_deps',
 389                                 'md_deps',
 390                                 array(
 391                                         'md_module' => $this->getName(),
 392                                         'md_skin' => $vary,
 393                                 ),
 394                                 __METHOD__
 395                         );
 396
 397                         if ( !is_null( $deps ) ) {
 398                                 $this->fileDeps[$vary] = self::expandRelativePaths(
 399                                         (array)FormatJson::decode( $deps, true )
 400                                 );
 401                         } else {
 402                                 $this->fileDeps[$vary] = array();
 403                         }
 404                 }
 405                 return $this->fileDeps[$vary];
 406         }
 407
 408         /**
 409          * Set in-object cache for file dependencies.
 410          *
 411          * This is used to retrieve data in batches. See ResourceLoader::preloadModuleInfo().
 412          * To save the data, use saveFileDependencies().
 413          *
 414          * @param ResourceLoaderContext $context
 415          * @param string[] $files Array of file names
 416          */
 417         public function setFileDependencies( ResourceLoaderContext $context, $files ) {
 418                 $vary = $context->getSkin() . '|' . $context->getLanguage();
 419                 $this->fileDeps[$vary] = $files;
 420         }
 421
 422         /**
 423          * Set the files this module depends on indirectly for a given skin.
 424          *
 425          * @since 1.27
 426          * @param ResourceLoaderContext $context
 427          * @param array $localFileRefs List of files
 428          */
 429         protected function saveFileDependencies( ResourceLoaderContext $context, $localFileRefs ) {
 430                 // Normalise array
 431                 $localFileRefs = array_values( array_unique( $localFileRefs ) );
 432                 sort( $localFileRefs );
 433
 434                 try {
 435                         // If the list has been modified since last time we cached it, update the cache
 436                         if ( $localFileRefs !== $this->getFileDependencies( $context ) ) {
 437                                 $vary = $context->getSkin() . '|' . $context->getLanguage();
 438                                 $dbw = wfGetDB( DB_MASTER );
 439                                 $dbw->replace( 'module_deps',
 440                                         array( array( 'md_module', 'md_skin' ) ), array(
 441                                                 'md_module' => $this->getName(),
 442                                                 'md_skin' => $vary,
 443                                                 // Use relative paths to avoid ghost entries when $IP changes (T111481)
 444                                                 'md_deps' => FormatJson::encode( self::getRelativePaths( $localFileRefs ) ),
 445                                         )
 446                                 );
 447                         }
 448                 } catch ( Exception $e ) {
 449                         wfDebugLog( 'resourceloader', __METHOD__ . ": failed to update DB: $e" );
 450                 }
 451         }
 452
 453         /**
 454          * Make file paths relative to MediaWiki directory.
 455          *
 456          * This is used to make file paths safe for storing in a database without the paths
 457          * becoming stale or incorrect when MediaWiki is moved or upgraded (T111481).
 458          *
 459          * @since 1.27
 460          * @param array $filePaths
 461          * @return array
 462          */
 463         public static function getRelativePaths( Array $filePaths ) {
 464                 global $IP;
 465                 return array_map( function ( $path ) use ( $IP ) {
 466                         return RelPath\getRelativePath( $path, $IP );
 467                 }, $filePaths );
 468         }
 469
 470         /**
 471          * Expand directories relative to $IP.
 472          *
 473          * @since 1.27
 474          * @param array $filePaths
 475          * @return array
 476          */
 477         public static function expandRelativePaths( Array $filePaths ) {
 478                 global $IP;
 479                 return array_map( function ( $path ) use ( $IP ) {
 480                         return RelPath\joinPath( $IP, $path );
 481                 }, $filePaths );
 482         }
 483
 484         /**
 485          * Get the hash of the message blob.
 486          *
 487          * @since 1.27
 488          * @param ResourceLoaderContext $context
 489          * @return string|null JSON blob or null if module has no messages
 490          */
 491         protected function getMessageBlob( ResourceLoaderContext $context ) {
 492                 if ( !$this->getMessages() ) {
 493                         // Don't bother consulting MessageBlobStore
 494                         return null;
 495                 }
 496                 // Message blobs may only vary language, not by context keys
 497                 $lang = $context->getLanguage();
 498                 if ( !isset( $this->msgBlobs[$lang] ) ) {
 499                         $this->getLogger()->warning( 'Message blob for {module} should have been preloaded', array(
 500                                 'module' => $this->getName(),
 501                         ) );
 502                         $store = $context->getResourceLoader()->getMessageBlobStore();
 503                         $this->msgBlobs[$lang] = $store->getBlob( $this, $lang );
 504                 }
 505                 return $this->msgBlobs[$lang];
 506         }
 507
 508         /**
 509          * Set in-object cache for message blobs.
 510          *
 511          * Used to allow fetching of message blobs in batches. See ResourceLoader::preloadModuleInfo().
 512          *
 513          * @since 1.27
 514          * @param string|null $blob JSON blob or null
 515          * @param string $lang Language code
 516          */
 517         public function setMessageBlob( $blob, $lang ) {
 518                 $this->msgBlobs[$lang] = $blob;
 519         }
 520
 521         /**
 522          * Get module-specific LESS variables, if any.
 523          *
 524          * @since 1.27
 525          * @param ResourceLoaderContext $context
 526          * @return array Module-specific LESS variables.
 527          */
 528         protected function getLessVars( ResourceLoaderContext $context ) {
 529                 return array();
 530         }
 531
 532         /**
 533          * Get an array of this module's resources. Ready for serving to the web.
 534          *
 535          * @since 1.26
 536          * @param ResourceLoaderContext $context
 537          * @return array
 538          */
 539         public function getModuleContent( ResourceLoaderContext $context ) {
 540                 $contextHash = $context->getHash();
 541                 // Cache this expensive operation. This calls builds the scripts, styles, and messages
 542                 // content which typically involves filesystem and/or database access.
 543                 if ( !array_key_exists( $contextHash, $this->contents ) ) {
 544                         $this->contents[$contextHash] = $this->buildContent( $context );
 545                 }
 546                 return $this->contents[$contextHash];
 547         }
 548
 549         /**
 550          * Bundle all resources attached to this module into an array.
 551          *
 552          * @since 1.26
 553          * @param ResourceLoaderContext $context
 554          * @return array
 555          */
 556         final protected function buildContent( ResourceLoaderContext $context ) {
 557                 $rl = $context->getResourceLoader();
 558                 $stats = RequestContext::getMain()->getStats();
 559                 $statStart = microtime( true );
 560
 561                 // Only include properties that are relevant to this context (e.g. only=scripts)
 562                 // and that are non-empty (e.g. don't include "templates" for modules without
 563                 // templates). This helps prevent invalidating cache for all modules when new
 564                 // optional properties are introduced.
 565                 $content = array();
 566
 567                 // Scripts
 568                 if ( $context->shouldIncludeScripts() ) {
 569                         // If we are in debug mode, we'll want to return an array of URLs if possible
 570                         // However, we can't do this if the module doesn't support it
 571                         // We also can't do this if there is an only= parameter, because we have to give
 572                         // the module a way to return a load.php URL without causing an infinite loop
 573                         if ( $context->getDebug() && !$context->getOnly() && $this->supportsURLLoading() ) {
 574                                 $scripts = $this->getScriptURLsForDebug( $context );
 575                         } else {
 576                                 $scripts = $this->getScript( $context );
 577                                 // rtrim() because there are usually a few line breaks
 578                                 // after the last ';'. A new line at EOF, a new line
 579                                 // added by ResourceLoaderFileModule::readScriptFiles, etc.
 580                                 if ( is_string( $scripts )
 581                                         && strlen( $scripts )
 582                                         && substr( rtrim( $scripts ), -1 ) !== ';'
 583                                 ) {
 584                                         // Append semicolon to prevent weird bugs caused by files not
 585                                         // terminating their statements right (bug 27054)
 586                                         $scripts .= ";\n";
 587                                 }
 588                         }
 589                         $content['scripts'] = $scripts;
 590                 }
 591
 592                 // Styles
 593                 if ( $context->shouldIncludeStyles() ) {
 594                         $styles = array();
 595                         // Don't create empty stylesheets like array( '' => '' ) for modules
 596                         // that don't *have* any stylesheets (bug 38024).
 597                         $stylePairs = $this->getStyles( $context );
 598                         if ( count( $stylePairs ) ) {
 599                                 // If we are in debug mode without &only= set, we'll want to return an array of URLs
 600                                 // See comment near shouldIncludeScripts() for more details
 601                                 if ( $context->getDebug() && !$context->getOnly() && $this->supportsURLLoading() ) {
 602                                         $styles = array(
 603                                                 'url' => $this->getStyleURLsForDebug( $context )
 604                                         );
 605                                 } else {
 606                                         // Minify CSS before embedding in mw.loader.implement call
 607                                         // (unless in debug mode)
 608                                         if ( !$context->getDebug() ) {
 609                                                 foreach ( $stylePairs as $media => $style ) {
 610                                                         // Can be either a string or an array of strings.
 611                                                         if ( is_array( $style ) ) {
 612                                                                 $stylePairs[$media] = array();
 613                                                                 foreach ( $style as $cssText ) {
 614                                                                         if ( is_string( $cssText ) ) {
 615                                                                                 $stylePairs[$media][] =
 616                                                                                         ResourceLoader::filter( 'minify-css', $cssText );
 617                                                                         }
 618                                                                 }
 619                                                         } elseif ( is_string( $style ) ) {
 620                                                                 $stylePairs[$media] = ResourceLoader::filter( 'minify-css', $style );
 621                                                         }
 622                                                 }
 623                                         }
 624                                         // Wrap styles into @media groups as needed and flatten into a numerical array
 625                                         $styles = array(
 626                                                 'css' => $rl->makeCombinedStyles( $stylePairs )
 627                                         );
 628                                 }
 629                         }
 630                         $content['styles'] = $styles;
 631                 }
 632
 633                 // Messages
 634                 $blob = $this->getMessageBlob( $context );
 635                 if ( $blob ) {
 636                         $content['messagesBlob'] = $blob;
 637                 }
 638
 639                 $templates = $this->getTemplates();
 640                 if ( $templates ) {
 641                         $content['templates'] = $templates;
 642                 }
 643
 644                 $statTiming = microtime( true ) - $statStart;
 645                 $statName = strtr( $this->getName(), '.', '_' );
 646                 $stats->timing( "resourceloader_build.all", 1000 * $statTiming );
 647                 $stats->timing( "resourceloader_build.$statName", 1000 * $statTiming );
 648
 649                 return $content;
 650         }
 651
 652         /**
 653          * Get a string identifying the current version of this module in a given context.
 654          *
 655          * Whenever anything happens that changes the module's response (e.g. scripts, styles, and
 656          * messages) this value must change. This value is used to store module responses in cache.
 657          * (Both client-side and server-side.)
 658          *
 659          * It is not recommended to override this directly. Use getDefinitionSummary() instead.
 660          * If overridden, one must call the parent getVersionHash(), append data and re-hash.
 661          *
 662          * This method should be quick because it is frequently run by ResourceLoaderStartUpModule to
 663          * propagate changes to the client and effectively invalidate cache.
 664          *
 665          * For backward-compatibility, the following optional data providers are automatically included:
 666          *
 667          * - getModifiedTime()
 668          * - getModifiedHash()
 669          *
 670          * @since 1.26
 671          * @param ResourceLoaderContext $context
 672          * @return string Hash (should use ResourceLoader::makeHash)
 673          */
 674         public function getVersionHash( ResourceLoaderContext $context ) {
 675                 // The startup module produces a manifest with versions representing the entire module.
 676                 // Typically, the request for the startup module itself has only=scripts. That must apply
 677                 // only to the startup module content, and not to the module version computed here.
 678                 $context = new DerivativeResourceLoaderContext( $context );
 679                 $context->setModules( array() );
 680                 // Version hash must cover all resources, regardless of startup request itself.
 681                 $context->setOnly( null );
 682                 // Compute version hash based on content, not debug urls.
 683                 $context->setDebug( false );
 684
 685                 // Cache this somewhat expensive operation. Especially because some classes
 686                 // (e.g. startup module) iterate more than once over all modules to get versions.
 687                 $contextHash = $context->getHash();
 688                 if ( !array_key_exists( $contextHash, $this->versionHash ) ) {
 689
 690                         if ( $this->enableModuleContentVersion() ) {
 691                                 // Detect changes directly
 692                                 $str = json_encode( $this->getModuleContent( $context ) );
 693                         } else {
 694                                 // Infer changes based on definition and other metrics
 695                                 $summary = $this->getDefinitionSummary( $context );
 696                                 if ( !isset( $summary['_cacheEpoch'] ) ) {
 697                                         throw new LogicException( 'getDefinitionSummary must call parent method' );
 698                                 }
 699                                 $str = json_encode( $summary );
 700
 701                                 $mtime = $this->getModifiedTime( $context );
 702                                 if ( $mtime !== null ) {
 703                                         // Support: MediaWiki 1.25 and earlier
 704                                         $str .= strval( $mtime );
 705                                 }
 706
 707                                 $mhash = $this->getModifiedHash( $context );
 708                                 if ( $mhash !== null ) {
 709                                         // Support: MediaWiki 1.25 and earlier
 710                                         $str .= strval( $mhash );
 711                                 }
 712                         }
 713
 714                         $this->versionHash[$contextHash] = ResourceLoader::makeHash( $str );
 715                 }
 716                 return $this->versionHash[$contextHash];
 717         }
 718
 719         /**
 720          * Whether to generate version hash based on module content.
 721          *
 722          * If a module requires database or file system access to build the module
 723          * content, consider disabling this in favour of manually tracking relevant
 724          * aspects in getDefinitionSummary(). See getVersionHash() for how this is used.
 725          *
 726          * @return bool
 727          */
 728         public function enableModuleContentVersion() {
 729                 return false;
 730         }
 731
 732         /**
 733          * Get the definition summary for this module.
 734          *
 735          * This is the method subclasses are recommended to use to track values in their
 736          * version hash. Call this in getVersionHash() and pass it to e.g. json_encode.
 737          *
 738          * Subclasses must call the parent getDefinitionSummary() and build on that.
 739          * It is recommended that each subclass appends its own new array. This prevents
 740          * clashes or accidental overwrites of existing keys and gives each subclass
 741          * its own scope for simple array keys.
 742          *
 743          * @code
 744          *     $summary = parent::getDefinitionSummary( $context );
 745          *     $summary[] = array(
 746          *         'foo' => 123,
 747          *         'bar' => 'quux',
 748          *     );
 749          *     return $summary;
 750          * @endcode
 751          *
 752          * Return an array containing values from all significant properties of this
 753          * module's definition.
 754          *
 755          * Be careful not to normalise too much. Especially preserve the order of things
 756          * that carry significance in getScript and getStyles (T39812).
 757          *
 758          * Avoid including things that are insiginificant (e.g. order of message keys is
 759          * insignificant and should be sorted to avoid unnecessary cache invalidation).
 760          *
 761          * This data structure must exclusively contain arrays and scalars as values (avoid
 762          * object instances) to allow simple serialisation using json_encode.
 763          *
 764          * If modules have a hash or timestamp from another source, that may be incuded as-is.
 765          *
 766          * A number of utility methods are available to help you gather data. These are not
 767          * called by default and must be included by the subclass' getDefinitionSummary().
 768          *
 769          * - getMessageBlob()
 770          *
 771          * @since 1.23
 772          * @param ResourceLoaderContext $context
 773          * @return array|null
 774          */
 775         public function getDefinitionSummary( ResourceLoaderContext $context ) {
 776                 return array(
 777                         '_class' => get_class( $this ),
 778                         '_cacheEpoch' => $this->getConfig()->get( 'CacheEpoch' ),
 779                 );
 780         }
 781
 782         /**
 783          * Get this module's last modification timestamp for a given context.
 784          *
 785          * @deprecated since 1.26 Use getDefinitionSummary() instead
 786          * @param ResourceLoaderContext $context Context object
 787          * @return int|null UNIX timestamp
 788          */
 789         public function getModifiedTime( ResourceLoaderContext $context ) {
 790                 return null;
 791         }
 792
 793         /**
 794          * Helper method for providing a version hash to getVersionHash().
 795          *
 796          * @deprecated since 1.26 Use getDefinitionSummary() instead
 797          * @param ResourceLoaderContext $context
 798          * @return string|null Hash
 799          */
 800         public function getModifiedHash( ResourceLoaderContext $context ) {
 801                 return null;
 802         }
 803
 804         /**
 805          * Back-compat dummy for old subclass implementations of getModifiedTime().
 806          *
 807          * This method used to use ObjectCache to track when a hash was first seen. That principle
 808          * stems from a time that ResourceLoader could only identify module versions by timestamp.
 809          * That is no longer the case. Use getDefinitionSummary() directly.
 810          *
 811          * @deprecated since 1.26 Superseded by getVersionHash()
 812          * @param ResourceLoaderContext $context
 813          * @return int UNIX timestamp
 814          */
 815         public function getHashMtime( ResourceLoaderContext $context ) {
 816                 if ( !is_string( $this->getModifiedHash( $context ) ) ) {
 817                         return 1;
 818                 }
 819                 // Dummy that is > 1
 820                 return 2;
 821         }
 822
 823         /**
 824          * Back-compat dummy for old subclass implementations of getModifiedTime().
 825          *
 826          * @since 1.23
 827          * @deprecated since 1.26 Superseded by getVersionHash()
 828          * @param ResourceLoaderContext $context
 829          * @return int UNIX timestamp
 830          */
 831         public function getDefinitionMtime( ResourceLoaderContext $context ) {
 832                 if ( $this->getDefinitionSummary( $context ) === null ) {
 833                         return 1;
 834                 }
 835                 // Dummy that is > 1
 836                 return 2;
 837         }
 838
 839         /**
 840          * Check whether this module is known to be empty. If a child class
 841          * has an easy and cheap way to determine that this module is
 842          * definitely going to be empty, it should override this method to
 843          * return true in that case. Callers may optimize the request for this
 844          * module away if this function returns true.
 845          * @param ResourceLoaderContext $context
 846          * @return bool
 847          */
 848         public function isKnownEmpty( ResourceLoaderContext $context ) {
 849                 return false;
 850         }
 851
 852         /** @var JSParser Lazy-initialized; use self::javaScriptParser() */
 853         private static $jsParser;
 854         private static $parseCacheVersion = 1;
 855
 856         /**
 857          * Validate a given script file; if valid returns the original source.
 858          * If invalid, returns replacement JS source that throws an exception.
 859          *
 860          * @param string $fileName
 861          * @param string $contents
 862          * @return string JS with the original, or a replacement error
 863          */
 864         protected function validateScriptFile( $fileName, $contents ) {
 865                 if ( $this->getConfig()->get( 'ResourceLoaderValidateJS' ) ) {
 866                         // Try for cache hit
 867                         $cache = ObjectCache::getMainWANInstance();
 868                         $key = $cache->makeKey(
 869                                 'resourceloader',
 870                                 'jsparse',
 871                                 self::$parseCacheVersion,
 872                                 md5( $contents )
 873                         );
 874                         $cacheEntry = $cache->get( $key );
 875                         if ( is_string( $cacheEntry ) ) {
 876                                 return $cacheEntry;
 877                         }
 878
 879                         $parser = self::javaScriptParser();
 880                         try {
 881                                 $parser->parse( $contents, $fileName, 1 );
 882                                 $result = $contents;
 883                         } catch ( Exception $e ) {
 884                                 // We'll save this to cache to avoid having to validate broken JS over and over...
 885                                 $err = $e->getMessage();
 886                                 $result = "mw.log.error(" .
 887                                         Xml::encodeJsVar( "JavaScript parse error: $err" ) . ");";
 888                         }
 889
 890                         $cache->set( $key, $result );
 891                         return $result;
 892                 } else {
 893                         return $contents;
 894                 }
 895         }
 896
 897         /**
 898          * @return JSParser
 899          */
 900         protected static function javaScriptParser() {
 901                 if ( !self::$jsParser ) {
 902                         self::$jsParser = new JSParser();
 903                 }
 904                 return self::$jsParser;
 905         }
 906
 907         /**
 908          * Safe version of filemtime(), which doesn't throw a PHP warning if the file doesn't exist.
 909          * Defaults to 1.
 910          *
 911          * @param string $filePath File path
 912          * @return int UNIX timestamp
 913          */
 914         protected static function safeFilemtime( $filePath ) {
 915                 MediaWiki\suppressWarnings();
 916                 $mtime = filemtime( $filePath ) ?: 1;
 917                 MediaWiki\restoreWarnings();
 918                 return $mtime;
 919         }
 920
 921         /**
 922          * Compute a non-cryptographic string hash of a file's contents.
 923          * If the file does not exist or cannot be read, returns an empty string.
 924          *
 925          * @since 1.26 Uses MD4 instead of SHA1.
 926          * @param string $filePath File path
 927          * @return string Hash
 928          */
 929         protected static function safeFileHash( $filePath ) {
 930                 return FileContentsHasher::getFileContentsHash( $filePath );
 931         }
 932 }