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