includes/resourceloader/ResourceLoader.php

   1 <?php
   2 /**
   3  * Base class for resource loading system.
   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 Roan Kattouw
  22  * @author Trevor Parscal
  23  */
  24
  25 use Psr\Log\LoggerAwareInterface;
  26 use Psr\Log\LoggerInterface;
  27 use Psr\Log\NullLogger;
  28 use WrappedString\WrappedString;
  29
  30 /**
  31  * Dynamic JavaScript and CSS resource loading system.
  32  *
  33  * Most of the documentation is on the MediaWiki documentation wiki starting at:
  34  *    https://www.mediawiki.org/wiki/ResourceLoader
  35  */
  36 class ResourceLoader implements LoggerAwareInterface {
  37         /** @var int */
  38         protected static $filterCacheVersion = 7;
  39
  40         /** @var bool */
  41         protected static $debugMode = null;
  42
  43         /** @var array */
  44         private static $lessVars = null;
  45
  46         /**
  47          * Module name/ResourceLoaderModule object pairs
  48          * @var array
  49          */
  50         protected $modules = array();
  51
  52         /**
  53          * Associative array mapping module name to info associative array
  54          * @var array
  55          */
  56         protected $moduleInfos = array();
  57
  58         /** @var Config $config */
  59         private $config;
  60
  61         /**
  62          * Associative array mapping framework ids to a list of names of test suite modules
  63          * like array( 'qunit' => array( 'mediawiki.tests.qunit.suites', 'ext.foo.tests', .. ), .. )
  64          * @var array
  65          */
  66         protected $testModuleNames = array();
  67
  68         /**
  69          * E.g. array( 'source-id' => 'http://.../load.php' )
  70          * @var array
  71          */
  72         protected $sources = array();
  73
  74         /**
  75          * Errors accumulated during current respond() call.
  76          * @var array
  77          */
  78         protected $errors = array();
  79
  80         /**
  81          * @var MessageBlobStore
  82          */
  83         protected $blobStore;
  84
  85         /**
  86          * @var LoggerInterface
  87          */
  88         private $logger;
  89
  90         /**
  91          * Load information stored in the database about modules.
  92          *
  93          * This method grabs modules dependencies from the database and updates modules
  94          * objects.
  95          *
  96          * This is not inside the module code because it is much faster to
  97          * request all of the information at once than it is to have each module
  98          * requests its own information. This sacrifice of modularity yields a substantial
  99          * performance improvement.
 100          *
 101          * @param array $modules List of module names to preload information for
 102          * @param ResourceLoaderContext $context Context to load the information within
 103          */
 104         public function preloadModuleInfo( array $modules, ResourceLoaderContext $context ) {
 105                 if ( !count( $modules ) ) {
 106                         // Or else Database*::select() will explode, plus it's cheaper!
 107                         return;
 108                 }
 109                 $dbr = wfGetDB( DB_SLAVE );
 110                 $skin = $context->getSkin();
 111                 $lang = $context->getLanguage();
 112
 113                 // Batched version of ResourceLoaderModule::getFileDependencies
 114                 $vary = "$skin|$lang";
 115                 $res = $dbr->select( 'module_deps', array( 'md_module', 'md_deps' ), array(
 116                                 'md_module' => $modules,
 117                                 'md_skin' => $vary,
 118                         ), __METHOD__
 119                 );
 120                 // Prime in-object cache values for each module
 121                 $modulesWithDeps = array();
 122                 foreach ( $res as $row ) {
 123                         $module = $this->getModule( $row->md_module );
 124                         if ( $module ) {
 125                                 $module->setFileDependencies( $context, FormatJson::decode( $row->md_deps, true ) );
 126                                 $modulesWithDeps[] = $row->md_module;
 127                         }
 128                 }
 129                 // Register the absence of a dependency row too
 130                 foreach ( array_diff( $modules, $modulesWithDeps ) as $name ) {
 131                         $module = $this->getModule( $name );
 132                         if ( $module ) {
 133                                 $this->getModule( $name )->setFileDependencies( $context, array() );
 134                         }
 135                 }
 136
 137                 // Get message blob mtimes. Only do this for modules with messages
 138                 $modulesWithMessages = array();
 139                 foreach ( $modules as $name ) {
 140                         $module = $this->getModule( $name );
 141                         if ( $module && count( $module->getMessages() ) ) {
 142                                 $modulesWithMessages[] = $name;
 143                         }
 144                 }
 145                 $modulesWithoutMessages = array_flip( $modules ); // Will be trimmed down by the loop below
 146                 if ( count( $modulesWithMessages ) ) {
 147                         $res = $dbr->select( 'msg_resource', array( 'mr_resource', 'mr_timestamp' ), array(
 148                                         'mr_resource' => $modulesWithMessages,
 149                                         'mr_lang' => $lang
 150                                 ), __METHOD__
 151                         );
 152                         foreach ( $res as $row ) {
 153                                 $module = $this->getModule( $row->mr_resource );
 154                                 if ( $module ) {
 155                                         $module->setMsgBlobMtime( $lang, wfTimestamp( TS_UNIX, $row->mr_timestamp ) );
 156                                         unset( $modulesWithoutMessages[$row->mr_resource] );
 157                                 }
 158                         }
 159                 }
 160                 foreach ( array_keys( $modulesWithoutMessages ) as $name ) {
 161                         $module = $this->getModule( $name );
 162                         if ( $module ) {
 163                                 $module->setMsgBlobMtime( $lang, 1 );
 164                         }
 165                 }
 166         }
 167
 168         /**
 169          * Run JavaScript or CSS data through a filter, caching the filtered result for future calls.
 170          *
 171          * Available filters are:
 172          *
 173          *    - minify-js \see JavaScriptMinifier::minify
 174          *    - minify-css \see CSSMin::minify
 175          *
 176          * If $data is empty, only contains whitespace or the filter was unknown,
 177          * $data is returned unmodified.
 178          *
 179          * @param string $filter Name of filter to run
 180          * @param string $data Text to filter, such as JavaScript or CSS text
 181          * @param array $options For back-compat, can also be the boolean value for "cacheReport". Keys:
 182          *  - (bool) cache: Whether to allow caching this data. Default: true.
 183          *  - (bool) cacheReport: Whether to include the "cache key" report comment. Default: false.
 184          * @return string Filtered data, or a comment containing an error message
 185          */
 186         public function filter( $filter, $data, $options = array() ) {
 187                 // Back-compat
 188                 if ( is_bool( $options ) ) {
 189                         $options = array( 'cacheReport' => $options );
 190                 }
 191                 // Defaults
 192                 $options += array( 'cache' => true, 'cacheReport' => false );
 193                 $stats = RequestContext::getMain()->getStats();
 194
 195                 // Don't filter empty content
 196                 if ( trim( $data ) === '' ) {
 197                         return $data;
 198                 }
 199
 200                 if ( !in_array( $filter, array( 'minify-js', 'minify-css' ) ) ) {
 201                         $this->logger->warning( 'Invalid filter {filter}', array(
 202                                 'filter' => $filter
 203                         ) );
 204                         return $data;
 205                 }
 206
 207                 if ( !$options['cache'] ) {
 208                         $result = self::applyFilter( $filter, $data, $this->config );
 209                 } else {
 210                         $key = wfGlobalCacheKey(
 211                                 'resourceloader',
 212                                 'filter',
 213                                 $filter,
 214                                 self::$filterCacheVersion, md5( $data )
 215                         );
 216                         $cache = wfGetCache( wfIsHHVM() ? CACHE_ACCEL : CACHE_ANYTHING );
 217                         $cacheEntry = $cache->get( $key );
 218                         if ( is_string( $cacheEntry ) ) {
 219                                 $stats->increment( "resourceloader_cache.$filter.hit" );
 220                                 return $cacheEntry;
 221                         }
 222                         $result = '';
 223                         try {
 224                                 $statStart = microtime( true );
 225                                 $result = self::applyFilter( $filter, $data, $this->config );
 226                                 $statTiming = microtime( true ) - $statStart;
 227                                 $stats->increment( "resourceloader_cache.$filter.miss" );
 228                                 $stats->timing( "resourceloader_cache.$filter.timing", 1000 * $statTiming );
 229                                 if ( $options['cacheReport'] ) {
 230                                         $result .= "\n/* cache key: $key */";
 231                                 }
 232                                 // Set a TTL since HHVM's APC doesn't have any limitation or eviction logic.
 233                                 $cache->set( $key, $result, 24 * 3600 );
 234                         } catch ( Exception $e ) {
 235                                 MWExceptionHandler::logException( $e );
 236                                 $this->logger->warning( 'Minification failed: {exception}', array(
 237                                         'exception' => $e
 238                                 ) );
 239                                 $this->errors[] = self::formatExceptionNoComment( $e );
 240                         }
 241                 }
 242
 243                 return $result;
 244         }
 245
 246         private static function applyFilter( $filter, $data, Config $config ) {
 247                 switch ( $filter ) {
 248                         case 'minify-js':
 249                                 return JavaScriptMinifier::minify( $data,
 250                                         $config->get( 'ResourceLoaderMinifierStatementsOnOwnLine' ),
 251                                         $config->get( 'ResourceLoaderMinifierMaxLineLength' )
 252                                 );
 253                         case 'minify-css':
 254                                 return CSSMin::minify( $data );
 255                 }
 256
 257                 return $data;
 258         }
 259
 260         /* Methods */
 261
 262         /**
 263          * Register core modules and runs registration hooks.
 264          * @param Config|null $config
 265          */
 266         public function __construct( Config $config = null, LoggerInterface $logger = null ) {
 267                 global $IP;
 268
 269                 if ( !$logger ) {
 270                         $logger = new NullLogger();
 271                 }
 272                 $this->setLogger( $logger );
 273
 274                 if ( !$config ) {
 275                         $this->logger->debug( __METHOD__ . ' was called without providing a Config instance' );
 276                         $config = ConfigFactory::getDefaultInstance()->makeConfig( 'main' );
 277                 }
 278                 $this->config = $config;
 279
 280                 // Add 'local' source first
 281                 $this->addSource( 'local', wfScript( 'load' ) );
 282
 283                 // Add other sources
 284                 $this->addSource( $config->get( 'ResourceLoaderSources' ) );
 285
 286                 // Register core modules
 287                 $this->register( include "$IP/resources/Resources.php" );
 288                 $this->register( include "$IP/resources/ResourcesOOUI.php" );
 289                 // Register extension modules
 290                 $this->register( $config->get( 'ResourceModules' ) );
 291                 Hooks::run( 'ResourceLoaderRegisterModules', array( &$this ) );
 292
 293                 if ( $config->get( 'EnableJavaScriptTest' ) === true ) {
 294                         $this->registerTestModules();
 295                 }
 296
 297                 $this->setMessageBlobStore( new MessageBlobStore() );
 298         }
 299
 300         /**
 301          * @return Config
 302          */
 303         public function getConfig() {
 304                 return $this->config;
 305         }
 306
 307         public function setLogger( LoggerInterface $logger ) {
 308                 $this->logger = $logger;
 309         }
 310
 311         /**
 312          * @since 1.26
 313          * @return MessageBlobStore
 314          */
 315         public function getMessageBlobStore() {
 316                 return $this->blobStore;
 317         }
 318
 319         /**
 320          * @since 1.25
 321          * @param MessageBlobStore $blobStore
 322          */
 323         public function setMessageBlobStore( MessageBlobStore $blobStore ) {
 324                 $this->blobStore = $blobStore;
 325         }
 326
 327         /**
 328          * Register a module with the ResourceLoader system.
 329          *
 330          * @param mixed $name Name of module as a string or List of name/object pairs as an array
 331          * @param array $info Module info array. For backwards compatibility with 1.17alpha,
 332          *   this may also be a ResourceLoaderModule object. Optional when using
 333          *   multiple-registration calling style.
 334          * @throws MWException If a duplicate module registration is attempted
 335          * @throws MWException If a module name contains illegal characters (pipes or commas)
 336          * @throws MWException If something other than a ResourceLoaderModule is being registered
 337          * @return bool False if there were any errors, in which case one or more modules were
 338          *   not registered
 339          */
 340         public function register( $name, $info = null ) {
 341
 342                 // Allow multiple modules to be registered in one call
 343                 $registrations = is_array( $name ) ? $name : array( $name => $info );
 344                 foreach ( $registrations as $name => $info ) {
 345                         // Disallow duplicate registrations
 346                         if ( isset( $this->moduleInfos[$name] ) ) {
 347                                 // A module has already been registered by this name
 348                                 throw new MWException(
 349                                         'ResourceLoader duplicate registration error. ' .
 350                                         'Another module has already been registered as ' . $name
 351                                 );
 352                         }
 353
 354                         // Check $name for validity
 355                         if ( !self::isValidModuleName( $name ) ) {
 356                                 throw new MWException( "ResourceLoader module name '$name' is invalid, "
 357                                         . "see ResourceLoader::isValidModuleName()" );
 358                         }
 359
 360                         // Attach module
 361                         if ( $info instanceof ResourceLoaderModule ) {
 362                                 $this->moduleInfos[$name] = array( 'object' => $info );
 363                                 $info->setName( $name );
 364                                 $this->modules[$name] = $info;
 365                         } elseif ( is_array( $info ) ) {
 366                                 // New calling convention
 367                                 $this->moduleInfos[$name] = $info;
 368                         } else {
 369                                 throw new MWException(
 370                                         'ResourceLoader module info type error for module \'' . $name .
 371                                         '\': expected ResourceLoaderModule or array (got: ' . gettype( $info ) . ')'
 372                                 );
 373                         }
 374
 375                         // Last-minute changes
 376
 377                         // Apply custom skin-defined styles to existing modules.
 378                         if ( $this->isFileModule( $name ) ) {
 379                                 foreach ( $this->config->get( 'ResourceModuleSkinStyles' ) as $skinName => $skinStyles ) {
 380                                         // If this module already defines skinStyles for this skin, ignore $wgResourceModuleSkinStyles.
 381                                         if ( isset( $this->moduleInfos[$name]['skinStyles'][$skinName] ) ) {
 382                                                 continue;
 383                                         }
 384
 385                                         // If $name is preceded with a '+', the defined style files will be added to 'default'
 386                                         // skinStyles, otherwise 'default' will be ignored as it normally would be.
 387                                         if ( isset( $skinStyles[$name] ) ) {
 388                                                 $paths = (array)$skinStyles[$name];
 389                                                 $styleFiles = array();
 390                                         } elseif ( isset( $skinStyles['+' . $name] ) ) {
 391                                                 $paths = (array)$skinStyles['+' . $name];
 392                                                 $styleFiles = isset( $this->moduleInfos[$name]['skinStyles']['default'] ) ?
 393                                                         (array)$this->moduleInfos[$name]['skinStyles']['default'] :
 394                                                         array();
 395                                         } else {
 396                                                 continue;
 397                                         }
 398
 399                                         // Add new file paths, remapping them to refer to our directories and not use settings
 400                                         // from the module we're modifying, which come from the base definition.
 401                                         list( $localBasePath, $remoteBasePath ) =
 402                                                 ResourceLoaderFileModule::extractBasePaths( $skinStyles );
 403
 404                                         foreach ( $paths as $path ) {
 405                                                 $styleFiles[] = new ResourceLoaderFilePath( $path, $localBasePath, $remoteBasePath );
 406                                         }
 407
 408                                         $this->moduleInfos[$name]['skinStyles'][$skinName] = $styleFiles;
 409                                 }
 410                         }
 411                 }
 412
 413         }
 414
 415         /**
 416          */
 417         public function registerTestModules() {
 418                 global $IP;
 419
 420                 if ( $this->config->get( 'EnableJavaScriptTest' ) !== true ) {
 421                         throw new MWException( 'Attempt to register JavaScript test modules '
 422                                 . 'but <code>$wgEnableJavaScriptTest</code> is false. '
 423                                 . 'Edit your <code>LocalSettings.php</code> to enable it.' );
 424                 }
 425
 426                 // Get core test suites
 427                 $testModules = array();
 428                 $testModules['qunit'] = array();
 429                 // Get other test suites (e.g. from extensions)
 430                 Hooks::run( 'ResourceLoaderTestModules', array( &$testModules, &$this ) );
 431
 432                 // Add the testrunner (which configures QUnit) to the dependencies.
 433                 // Since it must be ready before any of the test suites are executed.
 434                 foreach ( $testModules['qunit'] as &$module ) {
 435                         // Make sure all test modules are top-loading so that when QUnit starts
 436                         // on document-ready, it will run once and finish. If some tests arrive
 437                         // later (possibly after QUnit has already finished) they will be ignored.
 438                         $module['position'] = 'top';
 439                         $module['dependencies'][] = 'test.mediawiki.qunit.testrunner';
 440                 }
 441
 442                 $testModules['qunit'] =
 443                         ( include "$IP/tests/qunit/QUnitTestResources.php" ) + $testModules['qunit'];
 444
 445                 foreach ( $testModules as $id => $names ) {
 446                         // Register test modules
 447                         $this->register( $testModules[$id] );
 448
 449                         // Keep track of their names so that they can be loaded together
 450                         $this->testModuleNames[$id] = array_keys( $testModules[$id] );
 451                 }
 452
 453         }
 454
 455         /**
 456          * Add a foreign source of modules.
 457          *
 458          * @param array|string $id Source ID (string), or array( id1 => loadUrl, id2 => loadUrl, ... )
 459          * @param string|array $loadUrl load.php url (string), or array with loadUrl key for
 460          *  backwards-compatibility.
 461          * @throws MWException
 462          */
 463         public function addSource( $id, $loadUrl = null ) {
 464                 // Allow multiple sources to be registered in one call
 465                 if ( is_array( $id ) ) {
 466                         foreach ( $id as $key => $value ) {
 467                                 $this->addSource( $key, $value );
 468                         }
 469                         return;
 470                 }
 471
 472                 // Disallow duplicates
 473                 if ( isset( $this->sources[$id] ) ) {
 474                         throw new MWException(
 475                                 'ResourceLoader duplicate source addition error. ' .
 476                                 'Another source has already been registered as ' . $id
 477                         );
 478                 }
 479
 480                 // Pre 1.24 backwards-compatibility
 481                 if ( is_array( $loadUrl ) ) {
 482                         if ( !isset( $loadUrl['loadScript'] ) ) {
 483                                 throw new MWException(
 484                                         __METHOD__ . ' was passed an array with no "loadScript" key.'
 485                                 );
 486                         }
 487
 488                         $loadUrl = $loadUrl['loadScript'];
 489                 }
 490
 491                 $this->sources[$id] = $loadUrl;
 492         }
 493
 494         /**
 495          * Get a list of module names.
 496          *
 497          * @return array List of module names
 498          */
 499         public function getModuleNames() {
 500                 return array_keys( $this->moduleInfos );
 501         }
 502
 503         /**
 504          * Get a list of test module names for one (or all) frameworks.
 505          *
 506          * If the given framework id is unknkown, or if the in-object variable is not an array,
 507          * then it will return an empty array.
 508          *
 509          * @param string $framework Get only the test module names for one
 510          *   particular framework (optional)
 511          * @return array
 512          */
 513         public function getTestModuleNames( $framework = 'all' ) {
 514                 /** @todo api siteinfo prop testmodulenames modulenames */
 515                 if ( $framework == 'all' ) {
 516                         return $this->testModuleNames;
 517                 } elseif ( isset( $this->testModuleNames[$framework] )
 518                         && is_array( $this->testModuleNames[$framework] )
 519                 ) {
 520                         return $this->testModuleNames[$framework];
 521                 } else {
 522                         return array();
 523                 }
 524         }
 525
 526         /**
 527          * Check whether a ResourceLoader module is registered
 528          *
 529          * @since 1.25
 530          * @param string $name
 531          * @return bool
 532          */
 533         public function isModuleRegistered( $name ) {
 534                 return isset( $this->moduleInfos[$name] );
 535         }
 536
 537         /**
 538          * Get the ResourceLoaderModule object for a given module name.
 539          *
 540          * If an array of module parameters exists but a ResourceLoaderModule object has not
 541          * yet been instantiated, this method will instantiate and cache that object such that
 542          * subsequent calls simply return the same object.
 543          *
 544          * @param string $name Module name
 545          * @return ResourceLoaderModule|null If module has been registered, return a
 546          *  ResourceLoaderModule instance. Otherwise, return null.
 547          */
 548         public function getModule( $name ) {
 549                 if ( !isset( $this->modules[$name] ) ) {
 550                         if ( !isset( $this->moduleInfos[$name] ) ) {
 551                                 // No such module
 552                                 return null;
 553                         }
 554                         // Construct the requested object
 555                         $info = $this->moduleInfos[$name];
 556                         /** @var ResourceLoaderModule $object */
 557                         if ( isset( $info['object'] ) ) {
 558                                 // Object given in info array
 559                                 $object = $info['object'];
 560                         } else {
 561                                 if ( !isset( $info['class'] ) ) {
 562                                         $class = 'ResourceLoaderFileModule';
 563                                 } else {
 564                                         $class = $info['class'];
 565                                 }
 566                                 /** @var ResourceLoaderModule $object */
 567                                 $object = new $class( $info );
 568                                 $object->setConfig( $this->getConfig() );
 569                         }
 570                         $object->setName( $name );
 571                         $this->modules[$name] = $object;
 572                 }
 573
 574                 return $this->modules[$name];
 575         }
 576
 577         /**
 578          * Return whether the definition of a module corresponds to a simple ResourceLoaderFileModule.
 579          *
 580          * @param string $name Module name
 581          * @return bool
 582          */
 583         protected function isFileModule( $name ) {
 584                 if ( !isset( $this->moduleInfos[$name] ) ) {
 585                         return false;
 586                 }
 587                 $info = $this->moduleInfos[$name];
 588                 if ( isset( $info['object'] ) || isset( $info['class'] ) ) {
 589                         return false;
 590                 }
 591                 return true;
 592         }
 593
 594         /**
 595          * Get the list of sources.
 596          *
 597          * @return array Like array( id => load.php url, .. )
 598          */
 599         public function getSources() {
 600                 return $this->sources;
 601         }
 602
 603         /**
 604          * Get the URL to the load.php endpoint for the given
 605          * ResourceLoader source
 606          *
 607          * @since 1.24
 608          * @param string $source
 609          * @throws MWException On an invalid $source name
 610          * @return string
 611          */
 612         public function getLoadScript( $source ) {
 613                 if ( !isset( $this->sources[$source] ) ) {
 614                         throw new MWException( "The $source source was never registered in ResourceLoader." );
 615                 }
 616                 return $this->sources[$source];
 617         }
 618
 619         /**
 620          * @since 1.26
 621          * @param string $value
 622          * @return string Hash
 623          */
 624         public static function makeHash( $value ) {
 625                 // Use base64 to output more entropy in a more compact string (default hex is only base16).
 626                 // The first 8 chars of a base64 encoded digest represent the same binary as
 627                 // the first 12 chars of a hex encoded digest.
 628                 return substr( base64_encode( sha1( $value, true ) ), 0, 8 );
 629         }
 630
 631         /**
 632          * Helper method to get and combine versions of multiple modules.
 633          *
 634          * @since 1.26
 635          * @param ResourceLoaderContext $context
 636          * @param array $modules List of ResourceLoaderModule objects
 637          * @return string Hash
 638          */
 639         public function getCombinedVersion( ResourceLoaderContext $context, Array $modules ) {
 640                 if ( !$modules ) {
 641                         return '';
 642                 }
 643                 // Support: PHP 5.3 ("$this" for anonymous functions was added in PHP 5.4.0)
 644                 // http://php.net/functions.anonymous
 645                 $rl = $this;
 646                 $hashes = array_map( function ( $module ) use ( $rl, $context ) {
 647                         return $rl->getModule( $module )->getVersionHash( $context );
 648                 }, $modules );
 649                 return self::makeHash( implode( $hashes ) );
 650         }
 651
 652         /**
 653          * Output a response to a load request, including the content-type header.
 654          *
 655          * @param ResourceLoaderContext $context Context in which a response should be formed
 656          */
 657         public function respond( ResourceLoaderContext $context ) {
 658                 // Buffer output to catch warnings. Normally we'd use ob_clean() on the
 659                 // top-level output buffer to clear warnings, but that breaks when ob_gzhandler
 660                 // is used: ob_clean() will clear the GZIP header in that case and it won't come
 661                 // back for subsequent output, resulting in invalid GZIP. So we have to wrap
 662                 // the whole thing in our own output buffer to be sure the active buffer
 663                 // doesn't use ob_gzhandler.
 664                 // See http://bugs.php.net/bug.php?id=36514
 665                 ob_start();
 666
 667                 // Find out which modules are missing and instantiate the others
 668                 $modules = array();
 669                 $missing = array();
 670                 foreach ( $context->getModules() as $name ) {
 671                         $module = $this->getModule( $name );
 672                         if ( $module ) {
 673                                 // Do not allow private modules to be loaded from the web.
 674                                 // This is a security issue, see bug 34907.
 675                                 if ( $module->getGroup() === 'private' ) {
 676                                         $this->logger->debug( "Request for private module '$name' denied" );
 677                                         $this->errors[] = "Cannot show private module \"$name\"";
 678                                         continue;
 679                                 }
 680                                 $modules[$name] = $module;
 681                         } else {
 682                                 $missing[] = $name;
 683                         }
 684                 }
 685
 686                 try {
 687                         // Preload for getCombinedVersion()
 688                         $this->preloadModuleInfo( array_keys( $modules ), $context );
 689                 } catch ( Exception $e ) {
 690                         MWExceptionHandler::logException( $e );
 691                         $this->logger->warning( 'Preloading module info failed: {exception}', array(
 692                                 'exception' => $e
 693                         ) );
 694                         $this->errors[] = self::formatExceptionNoComment( $e );
 695                 }
 696
 697                 // Combine versions to propagate cache invalidation
 698                 $versionHash = '';
 699                 try {
 700                         $versionHash = $this->getCombinedVersion( $context, array_keys( $modules ) );
 701                 } catch ( Exception $e ) {
 702                         MWExceptionHandler::logException( $e );
 703                         $this->logger->warning( 'Calculating version hash failed: {exception}', array(
 704                                 'exception' => $e
 705                         ) );
 706                         $this->errors[] = self::formatExceptionNoComment( $e );
 707                 }
 708
 709                 // See RFC 2616 § 3.11 Entity Tags
 710                 // http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.11
 711                 $etag = 'W/"' . $versionHash . '"';
 712
 713                 // Try the client-side cache first
 714                 if ( $this->tryRespondNotModified( $context, $etag ) ) {
 715                         return; // output handled (buffers cleared)
 716                 }
 717
 718                 // Use file cache if enabled and available...
 719                 if ( $this->config->get( 'UseFileCache' ) ) {
 720                         $fileCache = ResourceFileCache::newFromContext( $context );
 721                         if ( $this->tryRespondFromFileCache( $fileCache, $context, $etag ) ) {
 722                                 return; // output handled
 723                         }
 724                 }
 725
 726                 // Generate a response
 727                 $response = $this->makeModuleResponse( $context, $modules, $missing );
 728
 729                 // Capture any PHP warnings from the output buffer and append them to the
 730                 // error list if we're in debug mode.
 731                 if ( $context->getDebug() && strlen( $warnings = ob_get_contents() ) ) {
 732                         $this->errors[] = $warnings;
 733                 }
 734
 735                 // Save response to file cache unless there are errors
 736                 if ( isset( $fileCache ) && !$this->errors && !count( $missing ) ) {
 737                         // Cache single modules and images...and other requests if there are enough hits
 738                         if ( ResourceFileCache::useFileCache( $context ) ) {
 739                                 if ( $fileCache->isCacheWorthy() ) {
 740                                         $fileCache->saveText( $response );
 741                                 } else {
 742                                         $fileCache->incrMissesRecent( $context->getRequest() );
 743                                 }
 744                         }
 745                 }
 746
 747                 $this->sendResponseHeaders( $context, $etag, (bool)$this->errors );
 748
 749                 // Remove the output buffer and output the response
 750                 ob_end_clean();
 751
 752                 if ( $context->getImageObj() && $this->errors ) {
 753                         // We can't show both the error messages and the response when it's an image.
 754                         $response = implode( "\n\n", $this->errors );
 755                 } elseif ( $this->errors ) {
 756                         $errorText = implode( "\n\n", $this->errors );
 757                         $errorResponse = self::makeComment( $errorText );
 758                         if ( $context->shouldIncludeScripts() ) {
 759                                 $errorResponse .= 'if (window.console && console.error) {'
 760                                         . Xml::encodeJsCall( 'console.error', array( $errorText ) )
 761                                         . "}\n";
 762                         }
 763
 764                         // Prepend error info to the response
 765                         $response = $errorResponse . $response;
 766                 }
 767
 768                 $this->errors = array();
 769                 echo $response;
 770
 771         }
 772
 773         /**
 774          * Send main response headers to the client.
 775          *
 776          * Deals with Content-Type, CORS (for stylesheets), and caching.
 777          *
 778          * @param ResourceLoaderContext $context
 779          * @param string $etag ETag header value
 780          * @param bool $errors Whether there are errors in the response
 781          * @return void
 782          */
 783         protected function sendResponseHeaders( ResourceLoaderContext $context, $etag, $errors ) {
 784                 $rlMaxage = $this->config->get( 'ResourceLoaderMaxage' );
 785                 // If a version wasn't specified we need a shorter expiry time for updates
 786                 // to propagate to clients quickly
 787                 // If there were errors, we also need a shorter expiry time so we can recover quickly
 788                 if ( is_null( $context->getVersion() ) || $errors ) {
 789                         $maxage = $rlMaxage['unversioned']['client'];
 790                         $smaxage = $rlMaxage['unversioned']['server'];
 791                 // If a version was specified we can use a longer expiry time since changing
 792                 // version numbers causes cache misses
 793                 } else {
 794                         $maxage = $rlMaxage['versioned']['client'];
 795                         $smaxage = $rlMaxage['versioned']['server'];
 796                 }
 797                 if ( $context->getImageObj() ) {
 798                         // Output different headers if we're outputting textual errors.
 799                         if ( $errors ) {
 800                                 header( 'Content-Type: text/plain; charset=utf-8' );
 801                         } else {
 802                                 $context->getImageObj()->sendResponseHeaders( $context );
 803                         }
 804                 } elseif ( $context->getOnly() === 'styles' ) {
 805                         header( 'Content-Type: text/css; charset=utf-8' );
 806                         header( 'Access-Control-Allow-Origin: *' );
 807                 } else {
 808                         header( 'Content-Type: text/javascript; charset=utf-8' );
 809                 }
 810                 // See RFC 2616 § 14.19 ETag
 811                 // http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.19
 812                 header( 'ETag: ' . $etag );
 813                 if ( $context->getDebug() ) {
 814                         // Do not cache debug responses
 815                         header( 'Cache-Control: private, no-cache, must-revalidate' );
 816                         header( 'Pragma: no-cache' );
 817                 } else {
 818                         header( "Cache-Control: public, max-age=$maxage, s-maxage=$smaxage" );
 819                         $exp = min( $maxage, $smaxage );
 820                         header( 'Expires: ' . wfTimestamp( TS_RFC2822, $exp + time() ) );
 821                 }
 822
 823                 // Send the current time expressed as fractional seconds since epoch,
 824                 // with microsecond precision. This helps distinguish hits from misses
 825                 // in edge caches.
 826                 header( 'MediaWiki-Timestamp: ' . microtime( true ) );
 827         }
 828
 829         /**
 830          * Respond with HTTP 304 Not Modified if appropiate.
 831          *
 832          * If there's an If-None-Match header, respond with a 304 appropriately
 833          * and clear out the output buffer. If the client cache is too old then do nothing.
 834          *
 835          * @param ResourceLoaderContext $context
 836          * @param string $etag ETag header value
 837          * @return bool True if HTTP 304 was sent and output handled
 838          */
 839         protected function tryRespondNotModified( ResourceLoaderContext $context, $etag ) {
 840                 // See RFC 2616 § 14.26 If-None-Match
 841                 // http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.26
 842                 $clientKeys = $context->getRequest()->getHeader( 'If-None-Match', WebRequest::GETHEADER_LIST );
 843                 // Never send 304s in debug mode
 844                 if ( $clientKeys !== false && !$context->getDebug() && in_array( $etag, $clientKeys ) ) {
 845                         // There's another bug in ob_gzhandler (see also the comment at
 846                         // the top of this function) that causes it to gzip even empty
 847                         // responses, meaning it's impossible to produce a truly empty
 848                         // response (because the gzip header is always there). This is
 849                         // a problem because 304 responses have to be completely empty
 850                         // per the HTTP spec, and Firefox behaves buggily when they're not.
 851                         // See also http://bugs.php.net/bug.php?id=51579
 852                         // To work around this, we tear down all output buffering before
 853                         // sending the 304.
 854                         wfResetOutputBuffers( /* $resetGzipEncoding = */ true );
 855
 856                         HttpStatus::header( 304 );
 857
 858                         $this->sendResponseHeaders( $context, $etag, false );
 859                         return true;
 860                 }
 861                 return false;
 862         }
 863
 864         /**
 865          * Send out code for a response from file cache if possible.
 866          *
 867          * @param ResourceFileCache $fileCache Cache object for this request URL
 868          * @param ResourceLoaderContext $context Context in which to generate a response
 869          * @param string $etag ETag header value
 870          * @return bool If this found a cache file and handled the response
 871          */
 872         protected function tryRespondFromFileCache(
 873                 ResourceFileCache $fileCache,
 874                 ResourceLoaderContext $context,
 875                 $etag
 876         ) {
 877                 $rlMaxage = $this->config->get( 'ResourceLoaderMaxage' );
 878                 // Buffer output to catch warnings.
 879                 ob_start();
 880                 // Get the maximum age the cache can be
 881                 $maxage = is_null( $context->getVersion() )
 882                         ? $rlMaxage['unversioned']['server']
 883                         : $rlMaxage['versioned']['server'];
 884                 // Minimum timestamp the cache file must have
 885                 $good = $fileCache->isCacheGood( wfTimestamp( TS_MW, time() - $maxage ) );
 886                 if ( !$good ) {
 887                         try { // RL always hits the DB on file cache miss...
 888                                 wfGetDB( DB_SLAVE );
 889                         } catch ( DBConnectionError $e ) { // ...check if we need to fallback to cache
 890                                 $good = $fileCache->isCacheGood(); // cache existence check
 891                         }
 892                 }
 893                 if ( $good ) {
 894                         $ts = $fileCache->cacheTimestamp();
 895                         // Send content type and cache headers
 896                         $this->sendResponseHeaders( $context, $etag, false );
 897                         $response = $fileCache->fetchText();
 898                         // Capture any PHP warnings from the output buffer and append them to the
 899                         // response in a comment if we're in debug mode.
 900                         if ( $context->getDebug() && strlen( $warnings = ob_get_contents() ) ) {
 901                                 $response = self::makeComment( $warnings ) . $response;
 902                         }
 903                         // Remove the output buffer and output the response
 904                         ob_end_clean();
 905                         echo $response . "\n/* Cached {$ts} */";
 906                         return true; // cache hit
 907                 }
 908                 // Clear buffer
 909                 ob_end_clean();
 910
 911                 return false; // cache miss
 912         }
 913
 914         /**
 915          * Generate a CSS or JS comment block.
 916          *
 917          * Only use this for public data, not error message details.
 918          *
 919          * @param string $text
 920          * @return string
 921          */
 922         public static function makeComment( $text ) {
 923                 $encText = str_replace( '*/', '* /', $text );
 924                 return "/*\n$encText\n*/\n";
 925         }
 926
 927         /**
 928          * Handle exception display.
 929          *
 930          * @param Exception $e Exception to be shown to the user
 931          * @return string Sanitized text in a CSS/JS comment that can be returned to the user
 932          */
 933         public static function formatException( $e ) {
 934                 return self::makeComment( self::formatExceptionNoComment( $e ) );
 935         }
 936
 937         /**
 938          * Handle exception display.
 939          *
 940          * @since 1.25
 941          * @param Exception $e Exception to be shown to the user
 942          * @return string Sanitized text that can be returned to the user
 943          */
 944         protected static function formatExceptionNoComment( $e ) {
 945                 global $wgShowExceptionDetails;
 946
 947                 if ( !$wgShowExceptionDetails ) {
 948                         return MWExceptionHandler::getPublicLogMessage( $e );
 949                 }
 950
 951                 return MWExceptionHandler::getLogMessage( $e );
 952         }
 953
 954         /**
 955          * Generate code for a response.
 956          *
 957          * @param ResourceLoaderContext $context Context in which to generate a response
 958          * @param ResourceLoaderModule[] $modules List of module objects keyed by module name
 959          * @param string[] $missing List of requested module names that are unregistered (optional)
 960          * @return string Response data
 961          */
 962         public function makeModuleResponse( ResourceLoaderContext $context,
 963                 array $modules, array $missing = array()
 964         ) {
 965                 $out = '';
 966                 $states = array();
 967
 968                 if ( !count( $modules ) && !count( $missing ) ) {
 969                         return <<<MESSAGE
 970 /* This file is the Web entry point for MediaWiki's ResourceLoader:
 971    <https://www.mediawiki.org/wiki/ResourceLoader>. In this request,
 972    no modules were requested. Max made me put this here. */
 973 MESSAGE;
 974                 }
 975
 976                 $image = $context->getImageObj();
 977                 if ( $image ) {
 978                         $data = $image->getImageData( $context );
 979                         if ( $data === false ) {
 980                                 $data = '';
 981                                 $this->errors[] = 'Image generation failed';
 982                         }
 983                         return $data;
 984                 }
 985
 986                 // Pre-fetch blobs
 987                 if ( $context->shouldIncludeMessages() ) {
 988                         try {
 989                                 $this->blobStore->get( $this, $modules, $context->getLanguage() );
 990                         } catch ( Exception $e ) {
 991                                 MWExceptionHandler::logException( $e );
 992                                 $this->logger->warning( 'Prefetching MessageBlobStore failed: {exception}', array(
 993                                         'exception' => $e
 994                                 ) );
 995                                 $this->errors[] = self::formatExceptionNoComment( $e );
 996                         }
 997                 }
 998
 999                 foreach ( $missing as $name ) {
1000                         $states[$name] = 'missing';
1001                 }
1002
1003                 // Generate output
1004                 $isRaw = false;
1005                 foreach ( $modules as $name => $module ) {
1006                         try {
1007                                 $content = $module->getModuleContent( $context );
1008
1009                                 // Append output
1010                                 switch ( $context->getOnly() ) {
1011                                         case 'scripts':
1012                                                 $scripts = $content['scripts'];
1013                                                 if ( is_string( $scripts ) ) {
1014                                                         // Load scripts raw...
1015                                                         $out .= $scripts;
1016                                                 } elseif ( is_array( $scripts ) ) {
1017                                                         // ...except when $scripts is an array of URLs
1018                                                         $out .= self::makeLoaderImplementScript( $name, $scripts, array(), array(), array() );
1019                                                 }
1020                                                 break;
1021                                         case 'styles':
1022                                                 $styles = $content['styles'];
1023                                                 // We no longer seperate into media, they are all combined now with
1024                                                 // custom media type groups into @media .. {} sections as part of the css string.
1025                                                 // Module returns either an empty array or a numerical array with css strings.
1026                                                 $out .= isset( $styles['css'] ) ? implode( '', $styles['css'] ) : '';
1027                                                 break;
1028                                         default:
1029                                                 $out .= self::makeLoaderImplementScript(
1030                                                         $name,
1031                                                         isset( $content['scripts'] ) ? $content['scripts'] : '',
1032                                                         isset( $content['styles'] ) ? $content['styles'] : array(),
1033                                                         isset( $content['messagesBlob'] ) ? new XmlJsCode( $content['messagesBlob'] ) : array(),
1034                                                         isset( $content['templates'] ) ? $content['templates'] : array()
1035                                                 );
1036                                                 break;
1037                                 }
1038                         } catch ( Exception $e ) {
1039                                 MWExceptionHandler::logException( $e );
1040                                 $this->logger->warning( 'Generating module package failed: {exception}', array(
1041                                         'exception' => $e
1042                                 ) );
1043                                 $this->errors[] = self::formatExceptionNoComment( $e );
1044
1045                                 // Respond to client with error-state instead of module implementation
1046                                 $states[$name] = 'error';
1047                                 unset( $modules[$name] );
1048                         }
1049                         $isRaw |= $module->isRaw();
1050                 }
1051
1052                 // Update module states
1053                 if ( $context->shouldIncludeScripts() && !$context->getRaw() && !$isRaw ) {
1054                         if ( count( $modules ) && $context->getOnly() === 'scripts' ) {
1055                                 // Set the state of modules loaded as only scripts to ready as
1056                                 // they don't have an mw.loader.implement wrapper that sets the state
1057                                 foreach ( $modules as $name => $module ) {
1058                                         $states[$name] = 'ready';
1059                                 }
1060                         }
1061
1062                         // Set the state of modules we didn't respond to with mw.loader.implement
1063                         if ( count( $states ) ) {
1064                                 $out .= self::makeLoaderStateScript( $states );
1065                         }
1066                 } else {
1067                         if ( count( $states ) ) {
1068                                 $this->errors[] = 'Problematic modules: ' .
1069                                         FormatJson::encode( $states, ResourceLoader::inDebugMode() );
1070                         }
1071                 }
1072
1073                 $enableFilterCache = true;
1074                 if ( count( $modules ) === 1 && reset( $modules ) instanceof ResourceLoaderUserTokensModule ) {
1075                         // If we're building the embedded user.tokens, don't cache (T84960)
1076                         $enableFilterCache = false;
1077                 }
1078
1079                 if ( !$context->getDebug() ) {
1080                         if ( $context->getOnly() === 'styles' ) {
1081                                 $out = $this->filter( 'minify-css', $out );
1082                         } else {
1083                                 $out = $this->filter( 'minify-js', $out, array(
1084                                         'cache' => $enableFilterCache
1085                                 ) );
1086                         }
1087                 }
1088
1089                 return $out;
1090         }
1091
1092         /* Static Methods */
1093
1094         /**
1095          * Return JS code that calls mw.loader.implement with given module properties.
1096          *
1097          * @param string $name Module name
1098          * @param mixed $scripts List of URLs to JavaScript files or String of JavaScript code
1099          * @param mixed $styles Array of CSS strings keyed by media type, or an array of lists of URLs
1100          *   to CSS files keyed by media type
1101          * @param mixed $messages List of messages associated with this module. May either be an
1102          *   associative array mapping message key to value, or a JSON-encoded message blob containing
1103          *   the same data, wrapped in an XmlJsCode object.
1104          * @param array $templates Keys are name of templates and values are the source of
1105          *   the template.
1106          * @throws MWException
1107          * @return string
1108          */
1109         public static function makeLoaderImplementScript(
1110                 $name, $scripts, $styles, $messages, $templates
1111         ) {
1112                 if ( is_string( $scripts ) ) {
1113                         // Site and user module are a legacy scripts that run in the global scope (no closure).
1114                         // Transportation as string instructs mw.loader.implement to use globalEval.
1115                         if ( $name === 'site' || $name === 'user' ) {
1116                                 // Minify manually because the general makeModuleResponse() minification won't be
1117                                 // effective here due to the script being a string instead of a function. (T107377)
1118                                 if ( !ResourceLoader::inDebugMode() ) {
1119                                         $scripts = self::applyFilter( 'minify-js', $scripts,
1120                                                 ConfigFactory::getDefaultInstance()->makeConfig( 'main' ) );
1121                                 }
1122                         } else {
1123                                 $scripts = new XmlJsCode( "function ( $, jQuery ) {\n{$scripts}\n}" );
1124                         }
1125                 } elseif ( !is_array( $scripts ) ) {
1126                         throw new MWException( 'Invalid scripts error. Array of URLs or string of code expected.' );
1127                 }
1128                 // mw.loader.implement requires 'styles', 'messages' and 'templates' to be objects (not
1129                 // arrays). json_encode considers empty arrays to be numerical and outputs "[]" instead
1130                 // of "{}". Force them to objects.
1131                 $module = array(
1132                         $name,
1133                         $scripts,
1134                         (object)$styles,
1135                         (object)$messages,
1136                         (object)$templates,
1137                 );
1138                 self::trimArray( $module );
1139
1140                 return Xml::encodeJsCall( 'mw.loader.implement', $module, ResourceLoader::inDebugMode() );
1141         }
1142
1143         /**
1144          * Returns JS code which, when called, will register a given list of messages.
1145          *
1146          * @param mixed $messages Either an associative array mapping message key to value, or a
1147          *   JSON-encoded message blob containing the same data, wrapped in an XmlJsCode object.
1148          * @return string
1149          */
1150         public static function makeMessageSetScript( $messages ) {
1151                 return Xml::encodeJsCall(
1152                         'mw.messages.set',
1153                         array( (object)$messages ),
1154                         ResourceLoader::inDebugMode()
1155                 );
1156         }
1157
1158         /**
1159          * Combines an associative array mapping media type to CSS into a
1160          * single stylesheet with "@media" blocks.
1161          *
1162          * @param array $stylePairs Array keyed by media type containing (arrays of) CSS strings
1163          * @return array
1164          */
1165         public static function makeCombinedStyles( array $stylePairs ) {
1166                 $out = array();
1167                 foreach ( $stylePairs as $media => $styles ) {
1168                         // ResourceLoaderFileModule::getStyle can return the styles
1169                         // as a string or an array of strings. This is to allow separation in
1170                         // the front-end.
1171                         $styles = (array)$styles;
1172                         foreach ( $styles as $style ) {
1173                                 $style = trim( $style );
1174                                 // Don't output an empty "@media print { }" block (bug 40498)
1175                                 if ( $style !== '' ) {
1176                                         // Transform the media type based on request params and config
1177                                         // The way that this relies on $wgRequest to propagate request params is slightly evil
1178                                         $media = OutputPage::transformCssMedia( $media );
1179
1180                                         if ( $media === '' || $media == 'all' ) {
1181                                                 $out[] = $style;
1182                                         } elseif ( is_string( $media ) ) {
1183                                                 $out[] = "@media $media {\n" . str_replace( "\n", "\n\t", "\t" . $style ) . "}";
1184                                         }
1185                                         // else: skip
1186                                 }
1187                         }
1188                 }
1189                 return $out;
1190         }
1191
1192         /**
1193          * Returns a JS call to mw.loader.state, which sets the state of a
1194          * module or modules to a given value. Has two calling conventions:
1195          *
1196          *    - ResourceLoader::makeLoaderStateScript( $name, $state ):
1197          *         Set the state of a single module called $name to $state
1198          *
1199          *    - ResourceLoader::makeLoaderStateScript( array( $name => $state, ... ) ):
1200          *         Set the state of modules with the given names to the given states
1201          *
1202          * @param string $name
1203          * @param string $state
1204          * @return string
1205          */
1206         public static function makeLoaderStateScript( $name, $state = null ) {
1207                 if ( is_array( $name ) ) {
1208                         return Xml::encodeJsCall(
1209                                 'mw.loader.state',
1210                                 array( $name ),
1211                                 ResourceLoader::inDebugMode()
1212                         );
1213                 } else {
1214                         return Xml::encodeJsCall(
1215                                 'mw.loader.state',
1216                                 array( $name, $state ),
1217                                 ResourceLoader::inDebugMode()
1218                         );
1219                 }
1220         }
1221
1222         /**
1223          * Returns JS code which calls the script given by $script. The script will
1224          * be called with local variables name, version, dependencies and group,
1225          * which will have values corresponding to $name, $version, $dependencies
1226          * and $group as supplied.
1227          *
1228          * @param string $name Module name
1229          * @param string $version Module version hash
1230          * @param array $dependencies List of module names on which this module depends
1231          * @param string $group Group which the module is in.
1232          * @param string $source Source of the module, or 'local' if not foreign.
1233          * @param string $script JavaScript code
1234          * @return string
1235          */
1236         public static function makeCustomLoaderScript( $name, $version, $dependencies,
1237                 $group, $source, $script
1238         ) {
1239                 $script = str_replace( "\n", "\n\t", trim( $script ) );
1240                 return Xml::encodeJsCall(
1241                         "( function ( name, version, dependencies, group, source ) {\n\t$script\n} )",
1242                         array( $name, $version, $dependencies, $group, $source ),
1243                         ResourceLoader::inDebugMode()
1244                 );
1245         }
1246
1247         private static function isEmptyObject( stdClass $obj ) {
1248                 foreach ( $obj as $key => $value ) {
1249                         return false;
1250                 }
1251                 return true;
1252         }
1253
1254         /**
1255          * Remove empty values from the end of an array.
1256          *
1257          * Values considered empty:
1258          *
1259          * - null
1260          * - array()
1261          * - new XmlJsCode( '{}' )
1262          * - new stdClass() // (object) array()
1263          *
1264          * @param Array $array
1265          */
1266         private static function trimArray( Array &$array ) {
1267                 $i = count( $array );
1268                 while ( $i-- ) {
1269                         if ( $array[$i] === null
1270                                 || $array[$i] === array()
1271                                 || ( $array[$i] instanceof XmlJsCode && $array[$i]->value === '{}' )
1272                                 || ( $array[$i] instanceof stdClass && self::isEmptyObject( $array[$i] ) )
1273                         ) {
1274                                 unset( $array[$i] );
1275                         } else {
1276                                 break;
1277                         }
1278                 }
1279         }
1280
1281         /**
1282          * Returns JS code which calls mw.loader.register with the given
1283          * parameters. Has three calling conventions:
1284          *
1285          *   - ResourceLoader::makeLoaderRegisterScript( $name, $version,
1286          *        $dependencies, $group, $source, $skip
1287          *     ):
1288          *        Register a single module.
1289          *
1290          *   - ResourceLoader::makeLoaderRegisterScript( array( $name1, $name2 ) ):
1291          *        Register modules with the given names.
1292          *
1293          *   - ResourceLoader::makeLoaderRegisterScript( array(
1294          *        array( $name1, $version1, $dependencies1, $group1, $source1, $skip1 ),
1295          *        array( $name2, $version2, $dependencies1, $group2, $source2, $skip2 ),
1296          *        ...
1297          *     ) ):
1298          *        Registers modules with the given names and parameters.
1299          *
1300          * @param string $name Module name
1301          * @param string $version Module version hash
1302          * @param array $dependencies List of module names on which this module depends
1303          * @param string $group Group which the module is in
1304          * @param string $source Source of the module, or 'local' if not foreign
1305          * @param string $skip Script body of the skip function
1306          * @return string
1307          */
1308         public static function makeLoaderRegisterScript( $name, $version = null,
1309                 $dependencies = null, $group = null, $source = null, $skip = null
1310         ) {
1311                 if ( is_array( $name ) ) {
1312                         // Build module name index
1313                         $index = array();
1314                         foreach ( $name as $i => &$module ) {
1315                                 $index[$module[0]] = $i;
1316                         }
1317
1318                         // Transform dependency names into indexes when possible, they will be resolved by
1319                         // mw.loader.register on the other end
1320                         foreach ( $name as &$module ) {
1321                                 if ( isset( $module[2] ) ) {
1322                                         foreach ( $module[2] as &$dependency ) {
1323                                                 if ( isset( $index[$dependency] ) ) {
1324                                                         $dependency = $index[$dependency];
1325                                                 }
1326                                         }
1327                                 }
1328                         }
1329
1330                         array_walk( $name, array( 'self', 'trimArray' ) );
1331
1332                         return Xml::encodeJsCall(
1333                                 'mw.loader.register',
1334                                 array( $name ),
1335                                 ResourceLoader::inDebugMode()
1336                         );
1337                 } else {
1338                         $registration = array( $name, $version, $dependencies, $group, $source, $skip );
1339                         self::trimArray( $registration );
1340                         return Xml::encodeJsCall(
1341                                 'mw.loader.register',
1342                                 $registration,
1343                                 ResourceLoader::inDebugMode()
1344                         );
1345                 }
1346         }
1347
1348         /**
1349          * Returns JS code which calls mw.loader.addSource() with the given
1350          * parameters. Has two calling conventions:
1351          *
1352          *   - ResourceLoader::makeLoaderSourcesScript( $id, $properties ):
1353          *       Register a single source
1354          *
1355          *   - ResourceLoader::makeLoaderSourcesScript( array( $id1 => $loadUrl, $id2 => $loadUrl, ... ) );
1356          *       Register sources with the given IDs and properties.
1357          *
1358          * @param string $id Source ID
1359          * @param array $properties Source properties (see addSource())
1360          * @return string
1361          */
1362         public static function makeLoaderSourcesScript( $id, $properties = null ) {
1363                 if ( is_array( $id ) ) {
1364                         return Xml::encodeJsCall(
1365                                 'mw.loader.addSource',
1366                                 array( $id ),
1367                                 ResourceLoader::inDebugMode()
1368                         );
1369                 } else {
1370                         return Xml::encodeJsCall(
1371                                 'mw.loader.addSource',
1372                                 array( $id, $properties ),
1373                                 ResourceLoader::inDebugMode()
1374                         );
1375                 }
1376         }
1377
1378         /**
1379          * Returns JS code which runs given JS code if the client-side framework is
1380          * present.
1381          *
1382          * @deprecated since 1.25; use makeInlineScript instead
1383          * @param string $script JavaScript code
1384          * @return string
1385          */
1386         public static function makeLoaderConditionalScript( $script ) {
1387                 return "window.RLQ = window.RLQ || []; window.RLQ.push( function () {\n" .
1388                         trim( $script ) . "\n} );";
1389         }
1390
1391         /**
1392          * Construct an inline script tag with given JS code.
1393          *
1394          * The code will be wrapped in a closure, and it will be executed by ResourceLoader
1395          * only if the client has adequate support for MediaWiki JavaScript code.
1396          *
1397          * @param string $script JavaScript code
1398          * @return WrappedString HTML
1399          */
1400         public static function makeInlineScript( $script ) {
1401                 $js = self::makeLoaderConditionalScript( $script );
1402                 return new WrappedString(
1403                         Html::inlineScript( $js ),
1404                         "<script>window.RLQ = window.RLQ || []; window.RLQ.push( function () {\n",
1405                         "\n} );</script>"
1406                 );
1407         }
1408
1409         /**
1410          * Returns JS code which will set the MediaWiki configuration array to
1411          * the given value.
1412          *
1413          * @param array $configuration List of configuration values keyed by variable name
1414          * @return string
1415          */
1416         public static function makeConfigSetScript( array $configuration ) {
1417                 if ( ResourceLoader::inDebugMode() ) {
1418                         return Xml::encodeJsCall( 'mw.config.set', array( $configuration ), true );
1419                 }
1420
1421                 $config = RequestContext::getMain()->getConfig();
1422                 $js = Xml::encodeJsCall( 'mw.config.set', array( $configuration ), false );
1423                 return self::applyFilter( 'minify-js', $js, $config );
1424         }
1425
1426         /**
1427          * Convert an array of module names to a packed query string.
1428          *
1429          * For example, array( 'foo.bar', 'foo.baz', 'bar.baz', 'bar.quux' )
1430          * becomes 'foo.bar,baz|bar.baz,quux'
1431          * @param array $modules List of module names (strings)
1432          * @return string Packed query string
1433          */
1434         public static function makePackedModulesString( $modules ) {
1435                 $groups = array(); // array( prefix => array( suffixes ) )
1436                 foreach ( $modules as $module ) {
1437                         $pos = strrpos( $module, '.' );
1438                         $prefix = $pos === false ? '' : substr( $module, 0, $pos );
1439                         $suffix = $pos === false ? $module : substr( $module, $pos + 1 );
1440                         $groups[$prefix][] = $suffix;
1441                 }
1442
1443                 $arr = array();
1444                 foreach ( $groups as $prefix => $suffixes ) {
1445                         $p = $prefix === '' ? '' : $prefix . '.';
1446                         $arr[] = $p . implode( ',', $suffixes );
1447                 }
1448                 $str = implode( '|', $arr );
1449                 return $str;
1450         }
1451
1452         /**
1453          * Determine whether debug mode was requested
1454          * Order of priority is 1) request param, 2) cookie, 3) $wg setting
1455          * @return bool
1456          */
1457         public static function inDebugMode() {
1458                 if ( self::$debugMode === null ) {
1459                         global $wgRequest, $wgResourceLoaderDebug;
1460                         self::$debugMode = $wgRequest->getFuzzyBool( 'debug',
1461                                 $wgRequest->getCookie( 'resourceLoaderDebug', '', $wgResourceLoaderDebug )
1462                         );
1463                 }
1464                 return self::$debugMode;
1465         }
1466
1467         /**
1468          * Reset static members used for caching.
1469          *
1470          * Global state and $wgRequest are evil, but we're using it right
1471          * now and sometimes we need to be able to force ResourceLoader to
1472          * re-evaluate the context because it has changed (e.g. in the test suite).
1473          */
1474         public static function clearCache() {
1475                 self::$debugMode = null;
1476         }
1477
1478         /**
1479          * Build a load.php URL
1480          *
1481          * @since 1.24
1482          * @param string $source Name of the ResourceLoader source
1483          * @param ResourceLoaderContext $context
1484          * @param array $extraQuery
1485          * @return string URL to load.php. May be protocol-relative if $wgLoadScript is, too.
1486          */
1487         public function createLoaderURL( $source, ResourceLoaderContext $context,
1488                 $extraQuery = array()
1489         ) {
1490                 $query = self::createLoaderQuery( $context, $extraQuery );
1491                 $script = $this->getLoadScript( $source );
1492
1493                 return wfAppendQuery( $script, $query );
1494         }
1495
1496         /**
1497          * Build a load.php URL
1498          * @deprecated since 1.24 Use createLoaderURL() instead
1499          * @param array $modules Array of module names (strings)
1500          * @param string $lang Language code
1501          * @param string $skin Skin name
1502          * @param string|null $user User name. If null, the &user= parameter is omitted
1503          * @param string|null $version Versioning timestamp
1504          * @param bool $debug Whether the request should be in debug mode
1505          * @param string|null $only &only= parameter
1506          * @param bool $printable Printable mode
1507          * @param bool $handheld Handheld mode
1508          * @param array $extraQuery Extra query parameters to add
1509          * @return string URL to load.php. May be protocol-relative if $wgLoadScript is, too.
1510          */
1511         public static function makeLoaderURL( $modules, $lang, $skin, $user = null,
1512                 $version = null, $debug = false, $only = null, $printable = false,
1513                 $handheld = false, $extraQuery = array()
1514         ) {
1515                 global $wgLoadScript;
1516
1517                 $query = self::makeLoaderQuery( $modules, $lang, $skin, $user, $version, $debug,
1518                         $only, $printable, $handheld, $extraQuery
1519                 );
1520
1521                 return wfAppendQuery( $wgLoadScript, $query );
1522         }
1523
1524         /**
1525          * Helper for createLoaderURL()
1526          *
1527          * @since 1.24
1528          * @see makeLoaderQuery
1529          * @param ResourceLoaderContext $context
1530          * @param array $extraQuery
1531          * @return array
1532          */
1533         public static function createLoaderQuery( ResourceLoaderContext $context, $extraQuery = array() ) {
1534                 return self::makeLoaderQuery(
1535                         $context->getModules(),
1536                         $context->getLanguage(),
1537                         $context->getSkin(),
1538                         $context->getUser(),
1539                         $context->getVersion(),
1540                         $context->getDebug(),
1541                         $context->getOnly(),
1542                         $context->getRequest()->getBool( 'printable' ),
1543                         $context->getRequest()->getBool( 'handheld' ),
1544                         $extraQuery
1545                 );
1546         }
1547
1548         /**
1549          * Build a query array (array representation of query string) for load.php. Helper
1550          * function for makeLoaderURL().
1551          *
1552          * @param array $modules
1553          * @param string $lang
1554          * @param string $skin
1555          * @param string $user
1556          * @param string $version
1557          * @param bool $debug
1558          * @param string $only
1559          * @param bool $printable
1560          * @param bool $handheld
1561          * @param array $extraQuery
1562          *
1563          * @return array
1564          */
1565         public static function makeLoaderQuery( $modules, $lang, $skin, $user = null,
1566                 $version = null, $debug = false, $only = null, $printable = false,
1567                 $handheld = false, $extraQuery = array()
1568         ) {
1569                 $query = array(
1570                         'modules' => self::makePackedModulesString( $modules ),
1571                         'lang' => $lang,
1572                         'skin' => $skin,
1573                         'debug' => $debug ? 'true' : 'false',
1574                 );
1575                 if ( $user !== null ) {
1576                         $query['user'] = $user;
1577                 }
1578                 if ( $version !== null ) {
1579                         $query['version'] = $version;
1580                 }
1581                 if ( $only !== null ) {
1582                         $query['only'] = $only;
1583                 }
1584                 if ( $printable ) {
1585                         $query['printable'] = 1;
1586                 }
1587                 if ( $handheld ) {
1588                         $query['handheld'] = 1;
1589                 }
1590                 $query += $extraQuery;
1591
1592                 // Make queries uniform in order
1593                 ksort( $query );
1594                 return $query;
1595         }
1596
1597         /**
1598          * Check a module name for validity.
1599          *
1600          * Module names may not contain pipes (|), commas (,) or exclamation marks (!) and can be
1601          * at most 255 bytes.
1602          *
1603          * @param string $moduleName Module name to check
1604          * @return bool Whether $moduleName is a valid module name
1605          */
1606         public static function isValidModuleName( $moduleName ) {
1607                 return !preg_match( '/[|,!]/', $moduleName ) && strlen( $moduleName ) <= 255;
1608         }
1609
1610         /**
1611          * Returns LESS compiler set up for use with MediaWiki
1612          *
1613          * @since 1.22
1614          * @since 1.26 added $extraVars parameter
1615          * @param Config $config
1616          * @param array $extraVars Associative array of extra (i.e., other than the
1617          *   globally-configured ones) that should be used for compilation.
1618          * @throws MWException
1619          * @return Less_Parser
1620          */
1621         public static function getLessCompiler( Config $config, $extraVars = array() ) {
1622                 // When called from the installer, it is possible that a required PHP extension
1623                 // is missing (at least for now; see bug 47564). If this is the case, throw an
1624                 // exception (caught by the installer) to prevent a fatal error later on.
1625                 if ( !class_exists( 'Less_Parser' ) ) {
1626                         throw new MWException( 'MediaWiki requires the less.php parser' );
1627                 }
1628
1629                 $parser = new Less_Parser;
1630                 $parser->ModifyVars( array_merge( self::getLessVars( $config ), $extraVars ) );
1631                 $parser->SetImportDirs( array_fill_keys( $config->get( 'ResourceLoaderLESSImportPaths' ), '' ) );
1632                 $parser->SetOption( 'relativeUrls', false );
1633                 $parser->SetCacheDir( $config->get( 'CacheDirectory' ) ?: wfTempDir() );
1634
1635                 return $parser;
1636         }
1637
1638         /**
1639          * Get global LESS variables.
1640          *
1641          * @param Config $config
1642          * @since 1.22
1643          * @return array Map of variable names to string CSS values.
1644          */
1645         public static function getLessVars( Config $config ) {
1646                 if ( !self::$lessVars ) {
1647                         $lessVars = $config->get( 'ResourceLoaderLESSVars' );
1648                         Hooks::run( 'ResourceLoaderGetLessVars', array( &$lessVars ) );
1649                         self::$lessVars = $lessVars;
1650                 }
1651                 return self::$lessVars;
1652         }
1653 }