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          * Currently these are only image files referenced by the module's CSS.
 378          *
 379          * @param string $skin Skin name
 380          * @return array List of files
 381          */
 382         public function getFileDependencies( $skin ) {
 383                 // Try in-object cache first
 384                 if ( isset( $this->fileDeps[$skin] ) ) {
 385                         return $this->fileDeps[$skin];
 386                 }
 387
 388                 $dbr = wfGetDB( DB_SLAVE );
 389                 $deps = $dbr->selectField( 'module_deps',
 390                         'md_deps',
 391                         array(
 392                                 'md_module' => $this->getName(),
 393                                 'md_skin' => $skin,
 394                         ),
 395                         __METHOD__
 396                 );
 397
 398                 if ( !is_null( $deps ) ) {
 399                         $this->fileDeps[$skin] = (array)FormatJson::decode( $deps, true );
 400                 } else {
 401                         $this->fileDeps[$skin] = array();
 402                 }
 403
 404                 return $this->fileDeps[$skin];
 405         }
 406
 407         /**
 408          * Set preloaded file dependency information. Used so we can load this
 409          * information for all modules at once.
 410          * @param string $skin Skin name
 411          * @param array $deps Array of file names
 412          */
 413         public function setFileDependencies( $skin, $deps ) {
 414                 $this->fileDeps[$skin] = $deps;
 415         }
 416
 417         /**
 418          * Get the last modification timestamp of the messages in this module for a given language.
 419          * @param string $lang Language code
 420          * @return int UNIX timestamp
 421          */
 422         public function getMsgBlobMtime( $lang ) {
 423                 if ( !isset( $this->msgBlobMtime[$lang] ) ) {
 424                         if ( !count( $this->getMessages() ) ) {
 425                                 return 1;
 426                         }
 427
 428                         $dbr = wfGetDB( DB_SLAVE );
 429                         $msgBlobMtime = $dbr->selectField( 'msg_resource',
 430                                 'mr_timestamp',
 431                                 array(
 432                                         'mr_resource' => $this->getName(),
 433                                         'mr_lang' => $lang
 434                                 ),
 435                                 __METHOD__
 436                         );
 437                         // If no blob was found, but the module does have messages, that means we need
 438                         // to regenerate it. Return NOW
 439                         if ( $msgBlobMtime === false ) {
 440                                 $msgBlobMtime = wfTimestampNow();
 441                         }
 442                         $this->msgBlobMtime[$lang] = wfTimestamp( TS_UNIX, $msgBlobMtime );
 443                 }
 444                 return $this->msgBlobMtime[$lang];
 445         }
 446
 447         /**
 448          * Set a preloaded message blob last modification timestamp. Used so we
 449          * can load this information for all modules at once.
 450          * @param string $lang Language code
 451          * @param int $mtime UNIX timestamp
 452          */
 453         public function setMsgBlobMtime( $lang, $mtime ) {
 454                 $this->msgBlobMtime[$lang] = $mtime;
 455         }
 456
 457         /**
 458          * Get an array of this module's resources. Ready for serving to the web.
 459          *
 460          * @since 1.26
 461          * @param ResourceLoaderContext $context
 462          * @return array
 463          */
 464         public function getModuleContent( ResourceLoaderContext $context ) {
 465                 $contextHash = $context->getHash();
 466                 // Cache this expensive operation. This calls builds the scripts, styles, and messages
 467                 // content which typically involves filesystem and/or database access.
 468                 if ( !array_key_exists( $contextHash, $this->contents ) ) {
 469                         $this->contents[$contextHash] = $this->buildContent( $context );
 470                 }
 471                 return $this->contents[$contextHash];
 472         }
 473
 474         /**
 475          * Bundle all resources attached to this module into an array.
 476          *
 477          * @since 1.26
 478          * @param ResourceLoaderContext $context
 479          * @return array
 480          */
 481         final protected function buildContent( ResourceLoaderContext $context ) {
 482                 $rl = $context->getResourceLoader();
 483                 $stats = RequestContext::getMain()->getStats();
 484                 $statStart = microtime( true );
 485
 486                 // Only include properties that are relevant to this context (e.g. only=scripts)
 487                 // and that are non-empty (e.g. don't include "templates" for modules without
 488                 // templates). This helps prevent invalidating cache for all modules when new
 489                 // optional properties are introduced.
 490                 $content = array();
 491
 492                 // Scripts
 493                 if ( $context->shouldIncludeScripts() ) {
 494                         // If we are in debug mode, we'll want to return an array of URLs if possible
 495                         // However, we can't do this if the module doesn't support it
 496                         // We also can't do this if there is an only= parameter, because we have to give
 497                         // the module a way to return a load.php URL without causing an infinite loop
 498                         if ( $context->getDebug() && !$context->getOnly() && $this->supportsURLLoading() ) {
 499                                 $scripts = $this->getScriptURLsForDebug( $context );
 500                         } else {
 501                                 $scripts = $this->getScript( $context );
 502                                 // rtrim() because there are usually a few line breaks
 503                                 // after the last ';'. A new line at EOF, a new line
 504                                 // added by ResourceLoaderFileModule::readScriptFiles, etc.
 505                                 if ( is_string( $scripts )
 506                                         && strlen( $scripts )
 507                                         && substr( rtrim( $scripts ), -1 ) !== ';'
 508                                 ) {
 509                                         // Append semicolon to prevent weird bugs caused by files not
 510                                         // terminating their statements right (bug 27054)
 511                                         $scripts .= ";\n";
 512                                 }
 513                         }
 514                         $content['scripts'] = $scripts;
 515                 }
 516
 517                 // Styles
 518                 if ( $context->shouldIncludeStyles() ) {
 519                         $styles = array();
 520                         // Don't create empty stylesheets like array( '' => '' ) for modules
 521                         // that don't *have* any stylesheets (bug 38024).
 522                         $stylePairs = $this->getStyles( $context );
 523                         if ( count( $stylePairs ) ) {
 524                                 // If we are in debug mode without &only= set, we'll want to return an array of URLs
 525                                 // See comment near shouldIncludeScripts() for more details
 526                                 if ( $context->getDebug() && !$context->getOnly() && $this->supportsURLLoading() ) {
 527                                         $styles = array(
 528                                                 'url' => $this->getStyleURLsForDebug( $context )
 529                                         );
 530                                 } else {
 531                                         // Minify CSS before embedding in mw.loader.implement call
 532                                         // (unless in debug mode)
 533                                         if ( !$context->getDebug() ) {
 534                                                 foreach ( $stylePairs as $media => $style ) {
 535                                                         // Can be either a string or an array of strings.
 536                                                         if ( is_array( $style ) ) {
 537                                                                 $stylePairs[$media] = array();
 538                                                                 foreach ( $style as $cssText ) {
 539                                                                         if ( is_string( $cssText ) ) {
 540                                                                                 $stylePairs[$media][] =
 541                                                                                         $rl->filter( 'minify-css', $cssText );
 542                                                                         }
 543                                                                 }
 544                                                         } elseif ( is_string( $style ) ) {
 545                                                                 $stylePairs[$media] = $rl->filter( 'minify-css', $style );
 546                                                         }
 547                                                 }
 548                                         }
 549                                         // Wrap styles into @media groups as needed and flatten into a numerical array
 550                                         $styles = array(
 551                                                 'css' => $rl->makeCombinedStyles( $stylePairs )
 552                                         );
 553                                 }
 554                         }
 555                         $content['styles'] = $styles;
 556                 }
 557
 558                 // Messages
 559                 $blobs = $rl->getMessageBlobStore()->get(
 560                         $rl,
 561                         array( $this->getName() => $this ),
 562                         $context->getLanguage()
 563                 );
 564                 if ( isset( $blobs[$this->getName()] ) ) {
 565                         $content['messagesBlob'] = $blobs[$this->getName()];
 566                 }
 567
 568                 $templates = $this->getTemplates();
 569                 if ( $templates ) {
 570                         $content['templates'] = $templates;
 571                 }
 572
 573                 $statTiming = microtime( true ) - $statStart;
 574                 $statName = strtr( $this->getName(), '.', '_' );
 575                 $stats->timing( "resourceloader_build.all", 1000 * $statTiming );
 576                 $stats->timing( "resourceloader_build.$statName", 1000 * $statTiming );
 577
 578                 return $content;
 579         }
 580
 581         /**
 582          * Get a string identifying the current version of this module in a given context.
 583          *
 584          * Whenever anything happens that changes the module's response (e.g. scripts, styles, and
 585          * messages) this value must change. This value is used to store module responses in cache.
 586          * (Both client-side and server-side.)
 587          *
 588          * It is not recommended to override this directly. Use getDefinitionSummary() instead.
 589          * If overridden, one must call the parent getVersionHash(), append data and re-hash.
 590          *
 591          * This method should be quick because it is frequently run by ResourceLoaderStartUpModule to
 592          * propagate changes to the client and effectively invalidate cache.
 593          *
 594          * For backward-compatibility, the following optional data providers are automatically included:
 595          *
 596          * - getModifiedTime()
 597          * - getModifiedHash()
 598          *
 599          * @since 1.26
 600          * @param ResourceLoaderContext $context
 601          * @return string Hash (should use ResourceLoader::makeHash)
 602          */
 603         public function getVersionHash( ResourceLoaderContext $context ) {
 604                 // The startup module produces a manifest with versions representing the entire module.
 605                 // Typically, the request for the startup module itself has only=scripts. That must apply
 606                 // only to the startup module content, and not to the module version computed here.
 607                 $context = new DerivativeResourceLoaderContext( $context );
 608                 $context->setModules( array() );
 609                 // Version hash must cover all resources, regardless of startup request itself.
 610                 $context->setOnly( null );
 611                 // Compute version hash based on content, not debug urls.
 612                 $context->setDebug( false );
 613
 614                 // Cache this somewhat expensive operation. Especially because some classes
 615                 // (e.g. startup module) iterate more than once over all modules to get versions.
 616                 $contextHash = $context->getHash();
 617                 if ( !array_key_exists( $contextHash, $this->versionHash ) ) {
 618
 619                         if ( $this->enableModuleContentVersion() ) {
 620                                 // Detect changes directly
 621                                 $str = json_encode( $this->getModuleContent( $context ) );
 622                         } else {
 623                                 // Infer changes based on definition and other metrics
 624                                 $summary = $this->getDefinitionSummary( $context );
 625                                 if ( !isset( $summary['_cacheEpoch'] ) ) {
 626                                         throw new LogicException( 'getDefinitionSummary must call parent method' );
 627                                 }
 628                                 $str = json_encode( $summary );
 629
 630                                 $mtime = $this->getModifiedTime( $context );
 631                                 if ( $mtime !== null ) {
 632                                         // Support: MediaWiki 1.25 and earlier
 633                                         $str .= strval( $mtime );
 634                                 }
 635
 636                                 $mhash = $this->getModifiedHash( $context );
 637                                 if ( $mhash !== null ) {
 638                                         // Support: MediaWiki 1.25 and earlier
 639                                         $str .= strval( $mhash );
 640                                 }
 641                         }
 642
 643                         $this->versionHash[$contextHash] = ResourceLoader::makeHash( $str );
 644                 }
 645                 return $this->versionHash[$contextHash];
 646         }
 647
 648         /**
 649          * Whether to generate version hash based on module content.
 650          *
 651          * If a module requires database or file system access to build the module
 652          * content, consider disabling this in favour of manually tracking relevant
 653          * aspects in getDefinitionSummary(). See getVersionHash() for how this is used.
 654          *
 655          * @return bool
 656          */
 657         public function enableModuleContentVersion() {
 658                 return false;
 659         }
 660
 661         /**
 662          * Get the definition summary for this module.
 663          *
 664          * This is the method subclasses are recommended to use to track values in their
 665          * version hash. Call this in getVersionHash() and pass it to e.g. json_encode.
 666          *
 667          * Subclasses must call the parent getDefinitionSummary() and build on that.
 668          * It is recommended that each subclass appends its own new array. This prevents
 669          * clashes or accidental overwrites of existing keys and gives each subclass
 670          * its own scope for simple array keys.
 671          *
 672          * @code
 673          *     $summary = parent::getDefinitionSummary( $context );
 674          *     $summary[] = array(
 675          *         'foo' => 123,
 676          *         'bar' => 'quux',
 677          *     );
 678          *     return $summary;
 679          * @endcode
 680          *
 681          * Return an array containing values from all significant properties of this
 682          * module's definition.
 683          *
 684          * Be careful not to normalise too much. Especially preserve the order of things
 685          * that carry significance in getScript and getStyles (T39812).
 686          *
 687          * Avoid including things that are insiginificant (e.g. order of message keys is
 688          * insignificant and should be sorted to avoid unnecessary cache invalidation).
 689          *
 690          * This data structure must exclusively contain arrays and scalars as values (avoid
 691          * object instances) to allow simple serialisation using json_encode.
 692          *
 693          * If modules have a hash or timestamp from another source, that may be incuded as-is.
 694          *
 695          * A number of utility methods are available to help you gather data. These are not
 696          * called by default and must be included by the subclass' getDefinitionSummary().
 697          *
 698          * - getMsgBlobMtime()
 699          *
 700          * @since 1.23
 701          * @param ResourceLoaderContext $context
 702          * @return array|null
 703          */
 704         public function getDefinitionSummary( ResourceLoaderContext $context ) {
 705                 return array(
 706                         '_class' => get_class( $this ),
 707                         '_cacheEpoch' => $this->getConfig()->get( 'CacheEpoch' ),
 708                 );
 709         }
 710
 711         /**
 712          * Get this module's last modification timestamp for a given context.
 713          *
 714          * @deprecated since 1.26 Use getDefinitionSummary() instead
 715          * @param ResourceLoaderContext $context Context object
 716          * @return int|null UNIX timestamp
 717          */
 718         public function getModifiedTime( ResourceLoaderContext $context ) {
 719                 return null;
 720         }
 721
 722         /**
 723          * Helper method for providing a version hash to getVersionHash().
 724          *
 725          * @deprecated since 1.26 Use getDefinitionSummary() instead
 726          * @param ResourceLoaderContext $context
 727          * @return string|null Hash
 728          */
 729         public function getModifiedHash( ResourceLoaderContext $context ) {
 730                 return null;
 731         }
 732
 733         /**
 734          * Back-compat dummy for old subclass implementations of getModifiedTime().
 735          *
 736          * This method used to use ObjectCache to track when a hash was first seen. That principle
 737          * stems from a time that ResourceLoader could only identify module versions by timestamp.
 738          * That is no longer the case. Use getDefinitionSummary() directly.
 739          *
 740          * @deprecated since 1.26 Superseded by getVersionHash()
 741          * @param ResourceLoaderContext $context
 742          * @return int UNIX timestamp
 743          */
 744         public function getHashMtime( ResourceLoaderContext $context ) {
 745                 if ( !is_string( $this->getModifiedHash( $context ) ) ) {
 746                         return 1;
 747                 }
 748                 // Dummy that is > 1
 749                 return 2;
 750         }
 751
 752         /**
 753          * Back-compat dummy for old subclass implementations of getModifiedTime().
 754          *
 755          * @since 1.23
 756          * @deprecated since 1.26 Superseded by getVersionHash()
 757          * @param ResourceLoaderContext $context
 758          * @return int UNIX timestamp
 759          */
 760         public function getDefinitionMtime( ResourceLoaderContext $context ) {
 761                 if ( $this->getDefinitionSummary( $context ) === null ) {
 762                         return 1;
 763                 }
 764                 // Dummy that is > 1
 765                 return 2;
 766         }
 767
 768         /**
 769          * Check whether this module is known to be empty. If a child class
 770          * has an easy and cheap way to determine that this module is
 771          * definitely going to be empty, it should override this method to
 772          * return true in that case. Callers may optimize the request for this
 773          * module away if this function returns true.
 774          * @param ResourceLoaderContext $context
 775          * @return bool
 776          */
 777         public function isKnownEmpty( ResourceLoaderContext $context ) {
 778                 return false;
 779         }
 780
 781         /** @var JSParser Lazy-initialized; use self::javaScriptParser() */
 782         private static $jsParser;
 783         private static $parseCacheVersion = 1;
 784
 785         /**
 786          * Validate a given script file; if valid returns the original source.
 787          * If invalid, returns replacement JS source that throws an exception.
 788          *
 789          * @param string $fileName
 790          * @param string $contents
 791          * @return string JS with the original, or a replacement error
 792          */
 793         protected function validateScriptFile( $fileName, $contents ) {
 794                 if ( $this->getConfig()->get( 'ResourceLoaderValidateJS' ) ) {
 795                         // Try for cache hit
 796                         // Use CACHE_ANYTHING since parsing JS is much slower than a DB query
 797                         $key = wfMemcKey(
 798                                 'resourceloader',
 799                                 'jsparse',
 800                                 self::$parseCacheVersion,
 801                                 md5( $contents )
 802                         );
 803                         $cache = wfGetCache( CACHE_ANYTHING );
 804                         $cacheEntry = $cache->get( $key );
 805                         if ( is_string( $cacheEntry ) ) {
 806                                 return $cacheEntry;
 807                         }
 808
 809                         $parser = self::javaScriptParser();
 810                         try {
 811                                 $parser->parse( $contents, $fileName, 1 );
 812                                 $result = $contents;
 813                         } catch ( Exception $e ) {
 814                                 // We'll save this to cache to avoid having to validate broken JS over and over...
 815                                 $err = $e->getMessage();
 816                                 $result = "mw.log.error(" .
 817                                         Xml::encodeJsVar( "JavaScript parse error: $err" ) . ");";
 818                         }
 819
 820                         $cache->set( $key, $result );
 821                         return $result;
 822                 } else {
 823                         return $contents;
 824                 }
 825         }
 826
 827         /**
 828          * @return JSParser
 829          */
 830         protected static function javaScriptParser() {
 831                 if ( !self::$jsParser ) {
 832                         self::$jsParser = new JSParser();
 833                 }
 834                 return self::$jsParser;
 835         }
 836
 837         /**
 838          * Safe version of filemtime(), which doesn't throw a PHP warning if the file doesn't exist.
 839          * Defaults to 1.
 840          *
 841          * @param string $filePath File path
 842          * @return int UNIX timestamp
 843          */
 844         protected static function safeFilemtime( $filePath ) {
 845                 MediaWiki\suppressWarnings();
 846                 $mtime = filemtime( $filePath ) ?: 1;
 847                 MediaWiki\restoreWarnings();
 848                 return $mtime;
 849         }
 850
 851         /**
 852          * Safe version of sha1_file(), which doesn't throw a PHP warning if the file doesn't exist.
 853          * Defaults to empty string.
 854          *
 855          * @param string $filePath File path
 856          * @return string Hash
 857          */
 858         protected static function safeFileHash( $filePath ) {
 859                 MediaWiki\suppressWarnings();
 860                 $hash = sha1_file( $filePath ) ?: '';
 861                 MediaWiki\restoreWarnings();
 862                 return $hash;
 863         }
 864 }