includes/registration/ExtensionRegistry.php

   1 <?php
   2
   3 /**
   4  * ExtensionRegistry class
   5  *
   6  * The Registry loads JSON files, and uses a Processor
   7  * to extract information from them. It also registers
   8  * classes with the autoloader.
   9  *
  10  * @since 1.25
  11  */
  12 class ExtensionRegistry {
  13
  14         /**
  15          * "requires" key that applies to MediaWiki core/$wgVersion
  16          */
  17         const MEDIAWIKI_CORE = 'MediaWiki';
  18
  19         /**
  20          * Version of the highest supported manifest version
  21          */
  22         const MANIFEST_VERSION = 1;
  23
  24         /**
  25          * Version of the oldest supported manifest version
  26          */
  27         const OLDEST_MANIFEST_VERSION = 1;
  28
  29         /**
  30          * Bump whenever the registration cache needs resetting
  31          */
  32         const CACHE_VERSION = 1;
  33
  34         /**
  35          * Special key that defines the merge strategy
  36          *
  37          * @since 1.26
  38          */
  39         const MERGE_STRATEGY = '_merge_strategy';
  40
  41         /**
  42          * @var BagOStuff
  43          */
  44         protected $cache;
  45
  46         /**
  47          * Array of loaded things, keyed by name, values are credits information
  48          *
  49          * @var array
  50          */
  51         private $loaded = array();
  52
  53         /**
  54          * List of paths that should be loaded
  55          *
  56          * @var array
  57          */
  58         protected $queued = array();
  59
  60         /**
  61          * Items in the JSON file that aren't being
  62          * set as globals
  63          *
  64          * @var array
  65          */
  66         protected $attributes = array();
  67
  68         /**
  69          * @var ExtensionRegistry
  70          */
  71         private static $instance;
  72
  73         /**
  74          * @return ExtensionRegistry
  75          */
  76         public static function getInstance() {
  77                 if ( self::$instance === null ) {
  78                         self::$instance = new self();
  79                 }
  80
  81                 return self::$instance;
  82         }
  83
  84         public function __construct() {
  85                 // We use a try/catch instead of the $fallback parameter because
  86                 // we don't want to fail here if $wgObjectCaches is not configured
  87                 // properly for APC setup
  88                 try {
  89                         $this->cache = ObjectCache::newAccelerator();
  90                 } catch ( MWException $e ) {
  91                         $this->cache = new EmptyBagOStuff();
  92                 }
  93         }
  94
  95         /**
  96          * @param string $path Absolute path to the JSON file
  97          */
  98         public function queue( $path ) {
  99                 global $wgExtensionInfoMTime;
 100
 101                 $mtime = $wgExtensionInfoMTime;
 102                 if ( $mtime === false ) {
 103                         if ( file_exists( $path ) ) {
 104                                 $mtime = filemtime( $path );
 105                         } else {
 106                                 throw new Exception( "$path does not exist!" );
 107                         }
 108                         if ( !$mtime ) {
 109                                 $err = error_get_last();
 110                                 throw new Exception( "Couldn't stat $path: {$err['message']}" );
 111                         }
 112                 }
 113                 $this->queued[$path] = $mtime;
 114         }
 115
 116         public function loadFromQueue() {
 117                 if ( !$this->queued ) {
 118                         return;
 119                 }
 120
 121                 // See if this queue is in APC
 122                 $key = wfMemcKey( 'registration', md5( json_encode( $this->queued ) ), self::CACHE_VERSION );
 123                 $data = $this->cache->get( $key );
 124                 if ( $data ) {
 125                         $this->exportExtractedData( $data );
 126                 } else {
 127                         $data = $this->readFromQueue( $this->queued );
 128                         $this->exportExtractedData( $data );
 129                         // Do this late since we don't want to extract it since we already
 130                         // did that, but it should be cached
 131                         $data['globals']['wgAutoloadClasses'] += $data['autoload'];
 132                         unset( $data['autoload'] );
 133                         $this->cache->set( $key, $data, 60 * 60 * 24 );
 134                 }
 135                 $this->queued = array();
 136         }
 137
 138         /**
 139          * Get the current load queue. Not intended to be used
 140          * outside of the installer.
 141          *
 142          * @return array
 143          */
 144         public function getQueue() {
 145                 return $this->queued;
 146         }
 147
 148         /**
 149          * Clear the current load queue. Not intended to be used
 150          * outside of the installer.
 151          */
 152         public function clearQueue() {
 153                 $this->queued = array();
 154         }
 155
 156         /**
 157          * Process a queue of extensions and return their extracted data
 158          *
 159          * @param array $queue keys are filenames, values are ignored
 160          * @return array extracted info
 161          * @throws Exception
 162          */
 163         public function readFromQueue( array $queue ) {
 164                 global $wgVersion;
 165                 $autoloadClasses = array();
 166                 $processor = new ExtensionProcessor();
 167                 $incompatible = array();
 168                 $coreVersionParser = new CoreVersionChecker( $wgVersion );
 169                 foreach ( $queue as $path => $mtime ) {
 170                         $json = file_get_contents( $path );
 171                         if ( $json === false ) {
 172                                 throw new Exception( "Unable to read $path, does it exist?" );
 173                         }
 174                         $info = json_decode( $json, /* $assoc = */ true );
 175                         if ( !is_array( $info ) ) {
 176                                 throw new Exception( "$path is not a valid JSON file." );
 177                         }
 178                         if ( !isset( $info['manifest_version'] ) ) {
 179                                 // For backwards-compatability, assume a version of 1
 180                                 $info['manifest_version'] = 1;
 181                         }
 182                         $version = $info['manifest_version'];
 183                         if ( $version < self::OLDEST_MANIFEST_VERSION || $version > self::MANIFEST_VERSION ) {
 184                                 throw new Exception( "$path: unsupported manifest_version: {$version}" );
 185                         }
 186                         $autoload = $this->processAutoLoader( dirname( $path ), $info );
 187                         // Set up the autoloader now so custom processors will work
 188                         $GLOBALS['wgAutoloadClasses'] += $autoload;
 189                         $autoloadClasses += $autoload;
 190                         // Check any constraints against MediaWiki core
 191                         $requires = $processor->getRequirements( $info );
 192                         if ( isset( $requires[self::MEDIAWIKI_CORE] )
 193                                 && !$coreVersionParser->check( $requires[self::MEDIAWIKI_CORE] )
 194                         ) {
 195                                 // Doesn't match, mark it as incompatible.
 196                                 $incompatible[] = "{$info['name']} is not compatible with the current "
 197                                         . "MediaWiki core (version {$wgVersion}), it requires: ". $requires[self::MEDIAWIKI_CORE]
 198                                         . '.';
 199                                 continue;
 200                         }
 201                         // Compatible, read and extract info
 202                         $processor->extractInfo( $path, $info, $version );
 203                 }
 204                 if ( $incompatible ) {
 205                         if ( count( $incompatible ) === 1 ) {
 206                                 throw new Exception( $incompatible[0] );
 207                         } else {
 208                                 throw new Exception( implode( "\n", $incompatible ) );
 209                         }
 210                 }
 211                 $data = $processor->getExtractedInfo();
 212                 // Need to set this so we can += to it later
 213                 $data['globals']['wgAutoloadClasses'] = array();
 214                 foreach ( $data['credits'] as $credit ) {
 215                         $data['globals']['wgExtensionCredits'][$credit['type']][] = $credit;
 216                 }
 217                 $data['globals']['wgExtensionCredits'][self::MERGE_STRATEGY] = 'array_merge_recursive';
 218                 $data['autoload'] = $autoloadClasses;
 219                 return $data;
 220         }
 221
 222         protected function exportExtractedData( array $info ) {
 223                 foreach ( $info['globals'] as $key => $val ) {
 224                         // If a merge strategy is set, read it and remove it from the value
 225                         // so it doesn't accidentally end up getting set.
 226                         // Need to check $val is an array for PHP 5.3 which will return
 227                         // true on isset( 'string'['foo'] ).
 228                         if ( isset( $val[self::MERGE_STRATEGY] ) && is_array( $val ) ) {
 229                                 $mergeStrategy = $val[self::MERGE_STRATEGY];
 230                                 unset( $val[self::MERGE_STRATEGY] );
 231                         } else {
 232                                 $mergeStrategy = 'array_merge';
 233                         }
 234
 235                         // Optimistic: If the global is not set, or is an empty array, replace it entirely.
 236                         // Will be O(1) performance.
 237                         if ( !isset( $GLOBALS[$key] ) || ( is_array( $GLOBALS[$key] ) && !$GLOBALS[$key] ) ) {
 238                                 $GLOBALS[$key] = $val;
 239                                 continue;
 240                         }
 241
 242                         if ( !is_array( $GLOBALS[$key] ) || !is_array( $val ) ) {
 243                                 // config setting that has already been overridden, don't set it
 244                                 continue;
 245                         }
 246
 247                         switch ( $mergeStrategy ) {
 248                                 case 'array_merge_recursive':
 249                                         $GLOBALS[$key] = array_merge_recursive( $GLOBALS[$key], $val );
 250                                         break;
 251                                 case 'array_plus_2d':
 252                                         // First merge items that are in both arrays
 253                                         foreach ( $GLOBALS[$key] as $name => &$groupVal ) {
 254                                                 if ( isset( $val[$name] ) ) {
 255                                                         $groupVal += $val[$name];
 256                                                 }
 257                                         }
 258                                         // Now add items that didn't exist yet
 259                                         $GLOBALS[$key] += $val;
 260                                         break;
 261                                 case 'array_plus':
 262                                         $GLOBALS[$key] = $val + $GLOBALS[$key];
 263                                         break;
 264                                 case 'array_merge':
 265                                         $GLOBALS[$key] = array_merge( $val, $GLOBALS[$key] );
 266                                         break;
 267                                 default:
 268                                         throw new UnexpectedValueException( "Unknown merge strategy '$mergeStrategy'" );
 269                         }
 270                 }
 271
 272                 foreach ( $info['defines'] as $name => $val ) {
 273                         define( $name, $val );
 274                 }
 275                 foreach ( $info['callbacks'] as $cb ) {
 276                         call_user_func( $cb );
 277                 }
 278
 279                 $this->loaded += $info['credits'];
 280
 281                 if ( $info['attributes'] ) {
 282                         if ( !$this->attributes ) {
 283                                 $this->attributes = $info['attributes'];
 284                         } else {
 285                                 $this->attributes = array_merge_recursive( $this->attributes, $info['attributes'] );
 286                         }
 287                 }
 288         }
 289
 290         /**
 291          * Loads and processes the given JSON file without delay
 292          *
 293          * If some extensions are already queued, this will load
 294          * those as well.
 295          *
 296          * @param string $path Absolute path to the JSON file
 297          */
 298         public function load( $path ) {
 299                 $this->loadFromQueue(); // First clear the queue
 300                 $this->queue( $path );
 301                 $this->loadFromQueue();
 302         }
 303
 304         /**
 305          * Whether a thing has been loaded
 306          * @param string $name
 307          * @return bool
 308          */
 309         public function isLoaded( $name ) {
 310                 return isset( $this->loaded[$name] );
 311         }
 312
 313         /**
 314          * @param string $name
 315          * @return array
 316          */
 317         public function getAttribute( $name ) {
 318                 if ( isset( $this->attributes[$name] ) ) {
 319                         return $this->attributes[$name];
 320                 } else {
 321                         return array();
 322                 }
 323         }
 324
 325         /**
 326          * Get information about all things
 327          *
 328          * @return array
 329          */
 330         public function getAllThings() {
 331                 return $this->loaded;
 332         }
 333
 334         /**
 335          * Mark a thing as loaded
 336          *
 337          * @param string $name
 338          * @param array $credits
 339          */
 340         protected function markLoaded( $name, array $credits ) {
 341                 $this->loaded[$name] = $credits;
 342         }
 343
 344         /**
 345          * Register classes with the autoloader
 346          *
 347          * @param string $dir
 348          * @param array $info
 349          * @return array
 350          */
 351         protected function processAutoLoader( $dir, array $info ) {
 352                 if ( isset( $info['AutoloadClasses'] ) ) {
 353                         // Make paths absolute, relative to the JSON file
 354                         return array_map( function( $file ) use ( $dir ) {
 355                                 return "$dir/$file";
 356                         }, $info['AutoloadClasses'] );
 357                 } else {
 358                         return array();
 359                 }
 360         }
 361 }