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   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_MESSAGES = 'messages';
  33      const TYPE_COMBINED = 'combined';
  34  
  35      # sitewide core module like a skin file or jQuery component
  36      const ORIGIN_CORE_SITEWIDE = 1;
  37  
  38      # per-user module generated by the software
  39      const ORIGIN_CORE_INDIVIDUAL = 2;
  40  
  41      # sitewide module generated from user-editable files, like MediaWiki:Common.js, or
  42      # modules accessible to multiple users, such as those generated by the Gadgets extension.
  43      const ORIGIN_USER_SITEWIDE = 3;
  44  
  45      # per-user module generated from user-editable files, like User:Me/vector.js
  46      const ORIGIN_USER_INDIVIDUAL = 4;
  47  
  48      # an access constant; make sure this is kept as the largest number in this group
  49      const ORIGIN_ALL = 10;
  50  
  51      # script and style modules form a hierarchy of trustworthiness, with core modules like
  52      # skins and jQuery as most trustworthy, and user scripts as least trustworthy.  We can
  53      # limit the types of scripts and styles we allow to load on, say, sensitive special
  54      # pages like Special:UserLogin and Special:Preferences
  55      protected $origin = self::ORIGIN_CORE_SITEWIDE;
  56  
  57      /* Protected Members */
  58  
  59      protected $name = null;
  60      protected $targets = array( 'desktop' );
  61  
  62      // In-object cache for file dependencies
  63      protected $fileDeps = array();
  64      // In-object cache for message blob mtime
  65      protected $msgBlobMtime = array();
  66  
  67      /**
  68       * @var Config
  69       */
  70      protected $config;
  71  
  72      /* Methods */
  73  
  74      /**
  75       * Get this module's name. This is set when the module is registered
  76       * with ResourceLoader::register()
  77       *
  78       * @return string|null Name (string) or null if no name was set
  79       */
  80  	public function getName() {
  81          return $this->name;
  82      }
  83  
  84      /**
  85       * Set this module's name. This is called by ResourceLoader::register()
  86       * when registering the module. Other code should not call this.
  87       *
  88       * @param string $name Name
  89       */
  90  	public function setName( $name ) {
  91          $this->name = $name;
  92      }
  93  
  94      /**
  95       * Get this module's origin. This is set when the module is registered
  96       * with ResourceLoader::register()
  97       *
  98       * @return int ResourceLoaderModule class constant, the subclass default
  99       *     if not set manually
 100       */
 101  	public function getOrigin() {
 102          return $this->origin;
 103      }
 104  
 105      /**
 106       * Set this module's origin. This is called by ResourceLoader::register()
 107       * when registering the module. Other code should not call this.
 108       *
 109       * @param int $origin Origin
 110       */
 111  	public function setOrigin( $origin ) {
 112          $this->origin = $origin;
 113      }
 114  
 115      /**
 116       * @param ResourceLoaderContext $context
 117       * @return bool
 118       */
 119  	public function getFlip( $context ) {
 120          global $wgContLang;
 121  
 122          return $wgContLang->getDir() !== $context->getDirection();
 123      }
 124  
 125      /**
 126       * Get all JS for this module for a given language and skin.
 127       * Includes all relevant JS except loader scripts.
 128       *
 129       * @param ResourceLoaderContext $context
 130       * @return string JavaScript code
 131       */
 132  	public function getScript( ResourceLoaderContext $context ) {
 133          // Stub, override expected
 134          return '';
 135      }
 136  
 137      /**
 138       * @return Config
 139       * @since 1.24
 140       */
 141  	public function getConfig() {
 142          if ( $this->config === null ) {
 143              // Ugh, fall back to default
 144              $this->config = ConfigFactory::getDefaultInstance()->makeConfig( 'main' );
 145          }
 146  
 147          return $this->config;
 148      }
 149  
 150      /**
 151       * @param Config $config
 152       * @since 1.24
 153       */
 154  	public function setConfig( Config $config ) {
 155          $this->config = $config;
 156      }
 157  
 158      /**
 159       * Get the URL or URLs to load for this module's JS in debug mode.
 160       * The default behavior is to return a load.php?only=scripts URL for
 161       * the module, but file-based modules will want to override this to
 162       * load the files directly.
 163       *
 164       * This function is called only when 1) we're in debug mode, 2) there
 165       * is no only= parameter and 3) supportsURLLoading() returns true.
 166       * #2 is important to prevent an infinite loop, therefore this function
 167       * MUST return either an only= URL or a non-load.php URL.
 168       *
 169       * @param ResourceLoaderContext $context
 170       * @return array Array of URLs
 171       */
 172  	public function getScriptURLsForDebug( ResourceLoaderContext $context ) {
 173          $resourceLoader = $context->getResourceLoader();
 174          $derivative = new DerivativeResourceLoaderContext( $context );
 175          $derivative->setModules( array( $this->getName() ) );
 176          $derivative->setOnly( 'scripts' );
 177          $derivative->setDebug( true );
 178  
 179          $url = $resourceLoader->createLoaderURL(
 180              $this->getSource(),
 181              $derivative
 182          );
 183  
 184          return array( $url );
 185      }
 186  
 187      /**
 188       * Whether this module supports URL loading. If this function returns false,
 189       * getScript() will be used even in cases (debug mode, no only param) where
 190       * getScriptURLsForDebug() would normally be used instead.
 191       * @return bool
 192       */
 193  	public function supportsURLLoading() {
 194          return true;
 195      }
 196  
 197      /**
 198       * Get all CSS for this module for a given skin.
 199       *
 200       * @param ResourceLoaderContext $context
 201       * @return array List of CSS strings or array of CSS strings keyed by media type.
 202       *  like array( 'screen' => '.foo { width: 0 }' );
 203       *  or array( 'screen' => array( '.foo { width: 0 }' ) );
 204       */
 205  	public function getStyles( ResourceLoaderContext $context ) {
 206          // Stub, override expected
 207          return array();
 208      }
 209  
 210      /**
 211       * Get the URL or URLs to load for this module's CSS in debug mode.
 212       * The default behavior is to return a load.php?only=styles URL for
 213       * the module, but file-based modules will want to override this to
 214       * load the files directly. See also getScriptURLsForDebug()
 215       *
 216       * @param ResourceLoaderContext $context
 217       * @return array Array( mediaType => array( URL1, URL2, ... ), ... )
 218       */
 219  	public function getStyleURLsForDebug( ResourceLoaderContext $context ) {
 220          $resourceLoader = $context->getResourceLoader();
 221          $derivative = new DerivativeResourceLoaderContext( $context );
 222          $derivative->setModules( array( $this->getName() ) );
 223          $derivative->setOnly( 'styles' );
 224          $derivative->setDebug( true );
 225  
 226          $url = $resourceLoader->createLoaderURL(
 227              $this->getSource(),
 228              $derivative
 229          );
 230  
 231          return array( 'all' => array( $url ) );
 232      }
 233  
 234      /**
 235       * Get the messages needed for this module.
 236       *
 237       * To get a JSON blob with messages, use MessageBlobStore::get()
 238       *
 239       * @return array List of message keys. Keys may occur more than once
 240       */
 241  	public function getMessages() {
 242          // Stub, override expected
 243          return array();
 244      }
 245  
 246      /**
 247       * Get the group this module is in.
 248       *
 249       * @return string Group name
 250       */
 251  	public function getGroup() {
 252          // Stub, override expected
 253          return null;
 254      }
 255  
 256      /**
 257       * Get the origin of this module. Should only be overridden for foreign modules.
 258       *
 259       * @return string Origin name, 'local' for local modules
 260       */
 261  	public function getSource() {
 262          // Stub, override expected
 263          return 'local';
 264      }
 265  
 266      /**
 267       * Where on the HTML page should this module's JS be loaded?
 268       *  - 'top': in the "<head>"
 269       *  - 'bottom': at the bottom of the "<body>"
 270       *
 271       * @return string
 272       */
 273  	public function getPosition() {
 274          return 'bottom';
 275      }
 276  
 277      /**
 278       * Whether this module's JS expects to work without the client-side ResourceLoader module.
 279       * Returning true from this function will prevent mw.loader.state() call from being
 280       * appended to the bottom of the script.
 281       *
 282       * @return bool
 283       */
 284  	public function isRaw() {
 285          return false;
 286      }
 287  
 288      /**
 289       * Get the loader JS for this module, if set.
 290       *
 291       * @return mixed JavaScript loader code as a string or boolean false if no custom loader set
 292       */
 293  	public function getLoaderScript() {
 294          // Stub, override expected
 295          return false;
 296      }
 297  
 298      /**
 299       * Get a list of modules this module depends on.
 300       *
 301       * Dependency information is taken into account when loading a module
 302       * on the client side.
 303       *
 304       * To add dependencies dynamically on the client side, use a custom
 305       * loader script, see getLoaderScript()
 306       * @return array List of module names as strings
 307       */
 308  	public function getDependencies() {
 309          // Stub, override expected
 310          return array();
 311      }
 312  
 313      /**
 314       * Get target(s) for the module, eg ['desktop'] or ['desktop', 'mobile']
 315       *
 316       * @return array Array of strings
 317       */
 318  	public function getTargets() {
 319          return $this->targets;
 320      }
 321  
 322      /**
 323       * Get the skip function.
 324       *
 325       * Modules that provide fallback functionality can provide a "skip function". This
 326       * function, if provided, will be passed along to the module registry on the client.
 327       * When this module is loaded (either directly or as a dependency of another module),
 328       * then this function is executed first. If the function returns true, the module will
 329       * instantly be considered "ready" without requesting the associated module resources.
 330       *
 331       * The value returned here must be valid javascript for execution in a private function.
 332       * It must not contain the "function () {" and "}" wrapper though.
 333       *
 334       * @return string|null A JavaScript function body returning a boolean value, or null
 335       */
 336  	public function getSkipFunction() {
 337          return null;
 338      }
 339  
 340      /**
 341       * Get the files this module depends on indirectly for a given skin.
 342       * Currently these are only image files referenced by the module's CSS.
 343       *
 344       * @param string $skin Skin name
 345       * @return array List of files
 346       */
 347  	public function getFileDependencies( $skin ) {
 348          // Try in-object cache first
 349          if ( isset( $this->fileDeps[$skin] ) ) {
 350              return $this->fileDeps[$skin];
 351          }
 352  
 353          $dbr = wfGetDB( DB_SLAVE );
 354          $deps = $dbr->selectField( 'module_deps', 'md_deps', array(
 355                  'md_module' => $this->getName(),
 356                  'md_skin' => $skin,
 357              ), __METHOD__
 358          );
 359          if ( !is_null( $deps ) ) {
 360              $this->fileDeps[$skin] = (array)FormatJson::decode( $deps, true );
 361          } else {
 362              $this->fileDeps[$skin] = array();
 363          }
 364          return $this->fileDeps[$skin];
 365      }
 366  
 367      /**
 368       * Set preloaded file dependency information. Used so we can load this
 369       * information for all modules at once.
 370       * @param string $skin Skin name
 371       * @param array $deps Array of file names
 372       */
 373  	public function setFileDependencies( $skin, $deps ) {
 374          $this->fileDeps[$skin] = $deps;
 375      }
 376  
 377      /**
 378       * Get the last modification timestamp of the message blob for this
 379       * module in a given language.
 380       * @param string $lang Language code
 381       * @return int UNIX timestamp, or 0 if the module doesn't have messages
 382       */
 383  	public function getMsgBlobMtime( $lang ) {
 384          if ( !isset( $this->msgBlobMtime[$lang] ) ) {
 385              if ( !count( $this->getMessages() ) ) {
 386                  return 0;
 387              }
 388  
 389              $dbr = wfGetDB( DB_SLAVE );
 390              $msgBlobMtime = $dbr->selectField( 'msg_resource', 'mr_timestamp', array(
 391                      'mr_resource' => $this->getName(),
 392                      'mr_lang' => $lang
 393                  ), __METHOD__
 394              );
 395              // If no blob was found, but the module does have messages, that means we need
 396              // to regenerate it. Return NOW
 397              if ( $msgBlobMtime === false ) {
 398                  $msgBlobMtime = wfTimestampNow();
 399              }
 400              $this->msgBlobMtime[$lang] = wfTimestamp( TS_UNIX, $msgBlobMtime );
 401          }
 402          return $this->msgBlobMtime[$lang];
 403      }
 404  
 405      /**
 406       * Set a preloaded message blob last modification timestamp. Used so we
 407       * can load this information for all modules at once.
 408       * @param string $lang Language code
 409       * @param int $mtime UNIX timestamp or 0 if there is no such blob
 410       */
 411  	public function setMsgBlobMtime( $lang, $mtime ) {
 412          $this->msgBlobMtime[$lang] = $mtime;
 413      }
 414  
 415      /* Abstract Methods */
 416  
 417      /**
 418       * Get this module's last modification timestamp for a given
 419       * combination of language, skin and debug mode flag. This is typically
 420       * the highest of each of the relevant components' modification
 421       * timestamps. Whenever anything happens that changes the module's
 422       * contents for these parameters, the mtime should increase.
 423       *
 424       * NOTE: The mtime of the module's messages is NOT automatically included.
 425       * If you want this to happen, you'll need to call getMsgBlobMtime()
 426       * yourself and take its result into consideration.
 427       *
 428       * NOTE: The mtime of the module's hash is NOT automatically included.
 429       * If your module provides a getModifiedHash() method, you'll need to call getHashMtime()
 430       * yourself and take its result into consideration.
 431       *
 432       * @param ResourceLoaderContext $context Context object
 433       * @return int UNIX timestamp
 434       */
 435  	public function getModifiedTime( ResourceLoaderContext $context ) {
 436          // 0 would mean now
 437          return 1;
 438      }
 439  
 440      /**
 441       * Helper method for calculating when the module's hash (if it has one) changed.
 442       *
 443       * @param ResourceLoaderContext $context
 444       * @return int UNIX timestamp or 0 if no hash was provided
 445       *  by getModifiedHash()
 446       */
 447  	public function getHashMtime( ResourceLoaderContext $context ) {
 448          $hash = $this->getModifiedHash( $context );
 449          if ( !is_string( $hash ) ) {
 450              return 0;
 451          }
 452  
 453          $cache = wfGetCache( CACHE_ANYTHING );
 454          $key = wfMemcKey( 'resourceloader', 'modulemodifiedhash', $this->getName(), $hash );
 455  
 456          $data = $cache->get( $key );
 457          if ( is_array( $data ) && $data['hash'] === $hash ) {
 458              // Hash is still the same, re-use the timestamp of when we first saw this hash.
 459              return $data['timestamp'];
 460          }
 461  
 462          $timestamp = wfTimestamp();
 463          $cache->set( $key, array(
 464              'hash' => $hash,
 465              'timestamp' => $timestamp,
 466          ) );
 467  
 468          return $timestamp;
 469      }
 470  
 471      /**
 472       * Get the hash for whatever this module may contain.
 473       *
 474       * This is the method subclasses should implement if they want to make
 475       * use of getHashMTime() inside getModifiedTime().
 476       *
 477       * @param ResourceLoaderContext $context
 478       * @return string|null Hash
 479       */
 480  	public function getModifiedHash( ResourceLoaderContext $context ) {
 481          return null;
 482      }
 483  
 484      /**
 485       * Helper method for calculating when this module's definition summary was last changed.
 486       *
 487       * @since 1.23
 488       *
 489       * @param ResourceLoaderContext $context
 490       * @return int UNIX timestamp or 0 if no definition summary was provided
 491       *  by getDefinitionSummary()
 492       */
 493  	public function getDefinitionMtime( ResourceLoaderContext $context ) {
 494          wfProfileIn( __METHOD__ );
 495          $summary = $this->getDefinitionSummary( $context );
 496          if ( $summary === null ) {
 497              wfProfileOut( __METHOD__ );
 498              return 0;
 499          }
 500  
 501          $hash = md5( json_encode( $summary ) );
 502  
 503          $cache = wfGetCache( CACHE_ANYTHING );
 504  
 505          // Embed the hash itself in the cache key. This allows for a few nifty things:
 506          // - During deployment, servers with old and new versions of the code communicating
 507          //   with the same memcached will not override the same key repeatedly increasing
 508          //   the timestamp.
 509          // - In case of the definition changing and then changing back in a short period of time
 510          //   (e.g. in case of a revert or a corrupt server) the old timestamp and client-side cache
 511          //   url will be re-used.
 512          // - If different context-combinations (e.g. same skin, same language or some combination
 513          //   thereof) result in the same definition, they will use the same hash and timestamp.
 514          $key = wfMemcKey( 'resourceloader', 'moduledefinition', $this->getName(), $hash );
 515  
 516          $data = $cache->get( $key );
 517          if ( is_int( $data ) && $data > 0 ) {
 518              // We've seen this hash before, re-use the timestamp of when we first saw it.
 519              wfProfileOut( __METHOD__ );
 520              return $data;
 521          }
 522  
 523          wfDebugLog( 'resourceloader', __METHOD__ . ": New definition hash for module "
 524              . "{$this->getName()} in context {$context->getHash()}: $hash." );
 525  
 526          $timestamp = time();
 527          $cache->set( $key, $timestamp );
 528  
 529          wfProfileOut( __METHOD__ );
 530          return $timestamp;
 531      }
 532  
 533      /**
 534       * Get the definition summary for this module.
 535       *
 536       * This is the method subclasses should implement if they want to make
 537       * use of getDefinitionMTime() inside getModifiedTime().
 538       *
 539       * Return an array containing values from all significant properties of this
 540       * module's definition. Be sure to include things that are explicitly ordered,
 541       * in their actaul order (bug 37812).
 542       *
 543       * Avoid including things that are insiginificant (e.g. order of message
 544       * keys is insignificant and should be sorted to avoid unnecessary cache
 545       * invalidation).
 546       *
 547       * Avoid including things already considered by other methods inside your
 548       * getModifiedTime(), such as file mtime timestamps.
 549       *
 550       * Serialisation is done using json_encode, which means object state is not
 551       * taken into account when building the hash. This data structure must only
 552       * contain arrays and scalars as values (avoid object instances) which means
 553       * it requires abstraction.
 554       *
 555       * @since 1.23
 556       *
 557       * @param ResourceLoaderContext $context
 558       * @return array|null
 559       */
 560  	public function getDefinitionSummary( ResourceLoaderContext $context ) {
 561          return array(
 562              'class' => get_class( $this ),
 563          );
 564      }
 565  
 566      /**
 567       * Check whether this module is known to be empty. If a child class
 568       * has an easy and cheap way to determine that this module is
 569       * definitely going to be empty, it should override this method to
 570       * return true in that case. Callers may optimize the request for this
 571       * module away if this function returns true.
 572       * @param ResourceLoaderContext $context
 573       * @return bool
 574       */
 575  	public function isKnownEmpty( ResourceLoaderContext $context ) {
 576          return false;
 577      }
 578  
 579      /** @var JSParser Lazy-initialized; use self::javaScriptParser() */
 580      private static $jsParser;
 581      private static $parseCacheVersion = 1;
 582  
 583      /**
 584       * Validate a given script file; if valid returns the original source.
 585       * If invalid, returns replacement JS source that throws an exception.
 586       *
 587       * @param string $fileName
 588       * @param string $contents
 589       * @return string JS with the original, or a replacement error
 590       */
 591  	protected function validateScriptFile( $fileName, $contents ) {
 592          if ( $this->getConfig()->get( 'ResourceLoaderValidateJS' ) ) {
 593              // Try for cache hit
 594              // Use CACHE_ANYTHING since filtering is very slow compared to DB queries
 595              $key = wfMemcKey( 'resourceloader', 'jsparse', self::$parseCacheVersion, md5( $contents ) );
 596              $cache = wfGetCache( CACHE_ANYTHING );
 597              $cacheEntry = $cache->get( $key );
 598              if ( is_string( $cacheEntry ) ) {
 599                  return $cacheEntry;
 600              }
 601  
 602              $parser = self::javaScriptParser();
 603              try {
 604                  $parser->parse( $contents, $fileName, 1 );
 605                  $result = $contents;
 606              } catch ( Exception $e ) {
 607                  // We'll save this to cache to avoid having to validate broken JS over and over...
 608                  $err = $e->getMessage();
 609                  $result = "throw new Error(" . Xml::encodeJsVar( "JavaScript parse error: $err" ) . ");";
 610              }
 611  
 612              $cache->set( $key, $result );
 613              return $result;
 614          } else {
 615              return $contents;
 616          }
 617      }
 618  
 619      /**
 620       * @return JSParser
 621       */
 622  	protected static function javaScriptParser() {
 623          if ( !self::$jsParser ) {
 624              self::$jsParser = new JSParser();
 625          }
 626          return self::$jsParser;
 627      }
 628  
 629      /**
 630       * Safe version of filemtime(), which doesn't throw a PHP warning if the file doesn't exist
 631       * but returns 1 instead.
 632       * @param string $filename File name
 633       * @return int UNIX timestamp, or 1 if the file doesn't exist
 634       */
 635  	protected static function safeFilemtime( $filename ) {
 636          if ( file_exists( $filename ) ) {
 637              return filemtime( $filename );
 638          } else {
 639              // We only ever map this function on an array if we're gonna call max() after,
 640              // so return our standard minimum timestamps here. This is 1, not 0, because
 641              // wfTimestamp(0) == NOW
 642              return 1;
 643          }
 644      }
 645  }