includes/resourceloader/ResourceLoaderModule.php

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