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 = 3;
  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::getLocalServerInstance();
  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                 global $wgVersion;
 118                 if ( !$this->queued ) {
 119                         return;
 120                 }
 121
 122                 // A few more things to vary the cache on
 123                 $versions = array(
 124                         'registration' => self::CACHE_VERSION,
 125                         'mediawiki' => $wgVersion
 126                 );
 127
 128                 // See if this queue is in APC
 129                 $key = wfMemcKey(
 130                         'registration',
 131                         md5( json_encode( $this->queued + $versions ) )
 132                 );
 133                 $data = $this->cache->get( $key );
 134                 if ( $data ) {
 135                         $this->exportExtractedData( $data );
 136                 } else {
 137                         $data = $this->readFromQueue( $this->queued );
 138                         $this->exportExtractedData( $data );
 139                         // Do this late since we don't want to extract it since we already
 140                         // did that, but it should be cached
 141                         $data['globals']['wgAutoloadClasses'] += $data['autoload'];
 142                         unset( $data['autoload'] );
 143                         $this->cache->set( $key, $data, 60 * 60 * 24 );
 144                 }
 145                 $this->queued = array();
 146         }
 147
 148         /**
 149          * Get the current load queue. Not intended to be used
 150          * outside of the installer.
 151          *
 152          * @return array
 153          */
 154         public function getQueue() {
 155                 return $this->queued;
 156         }
 157
 158         /**
 159          * Clear the current load queue. Not intended to be used
 160          * outside of the installer.
 161          */
 162         public function clearQueue() {
 163                 $this->queued = array();
 164         }
 165
 166         /**
 167          * Process a queue of extensions and return their extracted data
 168          *
 169          * @param array $queue keys are filenames, values are ignored
 170          * @return array extracted info
 171          * @throws Exception
 172          */
 173         public function readFromQueue( array $queue ) {
 174                 global $wgVersion;
 175                 $autoloadClasses = array();
 176                 $autoloaderPaths = array();
 177                 $processor = new ExtensionProcessor();
 178                 $incompatible = array();
 179                 $coreVersionParser = new CoreVersionChecker( $wgVersion );
 180                 foreach ( $queue as $path => $mtime ) {
 181                         $json = file_get_contents( $path );
 182                         if ( $json === false ) {
 183                                 throw new Exception( "Unable to read $path, does it exist?" );
 184                         }
 185                         $info = json_decode( $json, /* $assoc = */ true );
 186                         if ( !is_array( $info ) ) {
 187                                 throw new Exception( "$path is not a valid JSON file." );
 188                         }
 189                         if ( !isset( $info['manifest_version'] ) ) {
 190                                 // For backwards-compatability, assume a version of 1
 191                                 $info['manifest_version'] = 1;
 192                         }
 193                         $version = $info['manifest_version'];
 194                         if ( $version < self::OLDEST_MANIFEST_VERSION || $version > self::MANIFEST_VERSION ) {
 195                                 throw new Exception( "$path: unsupported manifest_version: {$version}" );
 196                         }
 197                         $autoload = $this->processAutoLoader( dirname( $path ), $info );
 198                         // Set up the autoloader now so custom processors will work
 199                         $GLOBALS['wgAutoloadClasses'] += $autoload;
 200                         $autoloadClasses += $autoload;
 201                         // Check any constraints against MediaWiki core
 202                         $requires = $processor->getRequirements( $info );
 203                         if ( isset( $requires[self::MEDIAWIKI_CORE] )
 204                                 && !$coreVersionParser->check( $requires[self::MEDIAWIKI_CORE] )
 205                         ) {
 206                                 // Doesn't match, mark it as incompatible.
 207                                 $incompatible[] = "{$info['name']} is not compatible with the current "
 208                                         . "MediaWiki core (version {$wgVersion}), it requires: " . $requires[self::MEDIAWIKI_CORE]
 209                                         . '.';
 210                                 continue;
 211                         }
 212                         // Get extra paths for later inclusion
 213                         $autoloaderPaths = array_merge( $autoloaderPaths,
 214                                 $processor->getExtraAutoloaderPaths( dirname( $path ), $info ) );
 215                         // Compatible, read and extract info
 216                         $processor->extractInfo( $path, $info, $version );
 217                 }
 218                 if ( $incompatible ) {
 219                         if ( count( $incompatible ) === 1 ) {
 220                                 throw new Exception( $incompatible[0] );
 221                         } else {
 222                                 throw new Exception( implode( "\n", $incompatible ) );
 223                         }
 224                 }
 225                 $data = $processor->getExtractedInfo();
 226                 // Need to set this so we can += to it later
 227                 $data['globals']['wgAutoloadClasses'] = array();
 228                 $data['autoload'] = $autoloadClasses;
 229                 $data['autoloaderPaths'] = $autoloaderPaths;
 230                 return $data;
 231         }
 232
 233         protected function exportExtractedData( array $info ) {
 234                 foreach ( $info['globals'] as $key => $val ) {
 235                         // If a merge strategy is set, read it and remove it from the value
 236                         // so it doesn't accidentally end up getting set.
 237                         // Need to check $val is an array for PHP 5.3 which will return
 238                         // true on isset( 'string'['foo'] ).
 239                         if ( isset( $val[self::MERGE_STRATEGY] ) && is_array( $val ) ) {
 240                                 $mergeStrategy = $val[self::MERGE_STRATEGY];
 241                                 unset( $val[self::MERGE_STRATEGY] );
 242                         } else {
 243                                 $mergeStrategy = 'array_merge';
 244                         }
 245
 246                         // Optimistic: If the global is not set, or is an empty array, replace it entirely.
 247                         // Will be O(1) performance.
 248                         if ( !isset( $GLOBALS[$key] ) || ( is_array( $GLOBALS[$key] ) && !$GLOBALS[$key] ) ) {
 249                                 $GLOBALS[$key] = $val;
 250                                 continue;
 251                         }
 252
 253                         if ( !is_array( $GLOBALS[$key] ) || !is_array( $val ) ) {
 254                                 // config setting that has already been overridden, don't set it
 255                                 continue;
 256                         }
 257
 258                         switch ( $mergeStrategy ) {
 259                                 case 'array_merge_recursive':
 260                                         $GLOBALS[$key] = array_merge_recursive( $GLOBALS[$key], $val );
 261                                         break;
 262                                 case 'array_plus_2d':
 263                                         $GLOBALS[$key] = wfArrayPlus2d( $GLOBALS[$key], $val );
 264                                         break;
 265                                 case 'array_plus':
 266                                         $GLOBALS[$key] += $val;
 267                                         break;
 268                                 case 'array_merge':
 269                                         $GLOBALS[$key] = array_merge( $val, $GLOBALS[$key] );
 270                                         break;
 271                                 default:
 272                                         throw new UnexpectedValueException( "Unknown merge strategy '$mergeStrategy'" );
 273                         }
 274                 }
 275
 276                 foreach ( $info['defines'] as $name => $val ) {
 277                         define( $name, $val );
 278                 }
 279                 foreach ( $info['callbacks'] as $cb ) {
 280                         call_user_func( $cb );
 281                 }
 282
 283                 foreach ( $info['autoloaderPaths'] as $path ) {
 284                         require_once $path;
 285                 }
 286
 287                 $this->loaded += $info['credits'];
 288                 if ( $info['attributes'] ) {
 289                         if ( !$this->attributes ) {
 290                                 $this->attributes = $info['attributes'];
 291                         } else {
 292                                 $this->attributes = array_merge_recursive( $this->attributes, $info['attributes'] );
 293                         }
 294                 }
 295         }
 296
 297         /**
 298          * Loads and processes the given JSON file without delay
 299          *
 300          * If some extensions are already queued, this will load
 301          * those as well.
 302          *
 303          * @param string $path Absolute path to the JSON file
 304          */
 305         public function load( $path ) {
 306                 $this->loadFromQueue(); // First clear the queue
 307                 $this->queue( $path );
 308                 $this->loadFromQueue();
 309         }
 310
 311         /**
 312          * Whether a thing has been loaded
 313          * @param string $name
 314          * @return bool
 315          */
 316         public function isLoaded( $name ) {
 317                 return isset( $this->loaded[$name] );
 318         }
 319
 320         /**
 321          * @param string $name
 322          * @return array
 323          */
 324         public function getAttribute( $name ) {
 325                 if ( isset( $this->attributes[$name] ) ) {
 326                         return $this->attributes[$name];
 327                 } else {
 328                         return array();
 329                 }
 330         }
 331
 332         /**
 333          * Get information about all things
 334          *
 335          * @return array
 336          */
 337         public function getAllThings() {
 338                 return $this->loaded;
 339         }
 340
 341         /**
 342          * Mark a thing as loaded
 343          *
 344          * @param string $name
 345          * @param array $credits
 346          */
 347         protected function markLoaded( $name, array $credits ) {
 348                 $this->loaded[$name] = $credits;
 349         }
 350
 351         /**
 352          * Register classes with the autoloader
 353          *
 354          * @param string $dir
 355          * @param array $info
 356          * @return array
 357          */
 358         protected function processAutoLoader( $dir, array $info ) {
 359                 if ( isset( $info['AutoloadClasses'] ) ) {
 360                         // Make paths absolute, relative to the JSON file
 361                         return array_map( function( $file ) use ( $dir ) {
 362                                 return "$dir/$file";
 363                         }, $info['AutoloadClasses'] );
 364                 } else {
 365                         return array();
 366                 }
 367         }
 368 }