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