includes/Revision.php

   1 <?php
   2
   3 /**
   4  * @todo document
   5  */
   6 class Revision {
   7         const DELETED_TEXT = 1;
   8         const DELETED_COMMENT = 2;
   9         const DELETED_USER = 4;
  10         const DELETED_RESTRICTED = 8;
  11         // Convenience field
  12         const SUPPRESSED_USER = 12;
  13         // Audience options for Revision::getText()
  14         const FOR_PUBLIC = 1;
  15         const FOR_THIS_USER = 2;
  16         const RAW = 3;
  17
  18         /**
  19          * Load a page revision from a given revision ID number.
  20          * Returns null if no such revision can be found.
  21          *
  22          * @param $id Integer
  23          * @return Revision or null
  24          */
  25         public static function newFromId( $id ) {
  26                 return Revision::newFromConds(
  27                         array( 'page_id=rev_page',
  28                                    'rev_id' => intval( $id ) ) );
  29         }
  30
  31         /**
  32          * Load either the current, or a specified, revision
  33          * that's attached to a given title. If not attached
  34          * to that title, will return null.
  35          *
  36          * @param $title Title
  37          * @param $id Integer
  38          * @return Revision or null
  39          */
  40         public static function newFromTitle( $title, $id = 0 ) {
  41                 $conds = array(
  42                         'page_namespace' => $title->getNamespace(),
  43                         'page_title' => $title->getDBkey()
  44                 );
  45                 if ( $id ) {
  46                         // Use the specified ID
  47                         $conds['rev_id'] = $id;
  48                 } elseif ( wfGetLB()->getServerCount() > 1 ) {
  49                         // Get the latest revision ID from the master
  50                         $dbw = wfGetDB( DB_MASTER );
  51                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
  52                         if ( $latest === false ) {
  53                                 // Page does not exist
  54                                 return null;
  55                         }
  56                         $conds['rev_id'] = $latest;
  57                 } else {
  58                         // Use a join to get the latest revision
  59                         $conds[] = 'rev_id=page_latest';
  60                 }
  61                 $conds[] = 'page_id=rev_page';
  62                 return Revision::newFromConds( $conds );
  63         }
  64
  65         /**
  66          * Make a fake revision object from an archive table row. This is queried
  67          * for permissions or even inserted (as in Special:Undelete)
  68          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
  69          *
  70          * @param $row
  71          * @param $overrides array
  72          *
  73          * @return Revision
  74          */
  75         public static function newFromArchiveRow( $row, $overrides = array() ) {
  76                 $attribs = $overrides + array(
  77                         'page'       => isset( $row->page_id ) ? $row->page_id : null,
  78                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
  79                         'comment'    => $row->ar_comment,
  80                         'user'       => $row->ar_user,
  81                         'user_text'  => $row->ar_user_text,
  82                         'timestamp'  => $row->ar_timestamp,
  83                         'minor_edit' => $row->ar_minor_edit,
  84                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
  85                         'deleted'    => $row->ar_deleted,
  86                         'len'        => $row->ar_len);
  87                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
  88                         // Pre-1.5 ar_text row
  89                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
  90                         if ( $attribs['text'] === false ) {
  91                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
  92                         }
  93                 }
  94                 return new self( $attribs );
  95         }
  96
  97         /**
  98          * Load a page revision from a given revision ID number.
  99          * Returns null if no such revision can be found.
 100          *
 101          * @param $db DatabaseBase
 102          * @param $id Integer
 103          * @return Revision or null
 104          */
 105         public static function loadFromId( $db, $id ) {
 106                 return Revision::loadFromConds( $db,
 107                         array( 'page_id=rev_page',
 108                                    'rev_id' => intval( $id ) ) );
 109         }
 110
 111         /**
 112          * Load either the current, or a specified, revision
 113          * that's attached to a given page. If not attached
 114          * to that page, will return null.
 115          *
 116          * @param $db DatabaseBase
 117          * @param $pageid Integer
 118          * @param $id Integer
 119          * @return Revision or null
 120          */
 121         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 122                 $conds = array( 'page_id=rev_page','rev_page' => intval( $pageid ), 'page_id'=>intval( $pageid ) );
 123                 if( $id ) {
 124                         $conds['rev_id'] = intval( $id );
 125                 } else {
 126                         $conds[] = 'rev_id=page_latest';
 127                 }
 128                 return Revision::loadFromConds( $db, $conds );
 129         }
 130
 131         /**
 132          * Load either the current, or a specified, revision
 133          * that's attached to a given page. If not attached
 134          * to that page, will return null.
 135          *
 136          * @param $db DatabaseBase
 137          * @param $title Title
 138          * @param $id Integer
 139          * @return Revision or null
 140          */
 141         public static function loadFromTitle( $db, $title, $id = 0 ) {
 142                 if( $id ) {
 143                         $matchId = intval( $id );
 144                 } else {
 145                         $matchId = 'page_latest';
 146                 }
 147                 return Revision::loadFromConds(
 148                         $db,
 149                         array( "rev_id=$matchId",
 150                                    'page_id=rev_page',
 151                                    'page_namespace' => $title->getNamespace(),
 152                                    'page_title'     => $title->getDBkey() ) );
 153         }
 154
 155         /**
 156          * Load the revision for the given title with the given timestamp.
 157          * WARNING: Timestamps may in some circumstances not be unique,
 158          * so this isn't the best key to use.
 159          *
 160          * @param $db DatabaseBase
 161          * @param $title Title
 162          * @param $timestamp String
 163          * @return Revision or null
 164          */
 165         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 166                 return Revision::loadFromConds(
 167                         $db,
 168                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 169                                    'page_id=rev_page',
 170                                    'page_namespace' => $title->getNamespace(),
 171                                    'page_title'     => $title->getDBkey() ) );
 172         }
 173
 174         /**
 175          * Given a set of conditions, fetch a revision.
 176          *
 177          * @param $conditions Array
 178          * @return Revision or null
 179          */
 180         public static function newFromConds( $conditions ) {
 181                 $db = wfGetDB( DB_SLAVE );
 182                 $row = Revision::loadFromConds( $db, $conditions );
 183                 if( is_null( $row ) && wfGetLB()->getServerCount() > 1 ) {
 184                         $dbw = wfGetDB( DB_MASTER );
 185                         $row = Revision::loadFromConds( $dbw, $conditions );
 186                 }
 187                 return $row;
 188         }
 189
 190         /**
 191          * Given a set of conditions, fetch a revision from
 192          * the given database connection.
 193          *
 194          * @param $db DatabaseBase
 195          * @param $conditions Array
 196          * @return Revision or null
 197          */
 198         private static function loadFromConds( $db, $conditions ) {
 199                 $res = Revision::fetchFromConds( $db, $conditions );
 200                 if( $res ) {
 201                         $row = $res->fetchObject();
 202                         $res->free();
 203                         if( $row ) {
 204                                 $ret = new Revision( $row );
 205                                 return $ret;
 206                         }
 207                 }
 208                 $ret = null;
 209                 return $ret;
 210         }
 211
 212         /**
 213          * Return a wrapper for a series of database rows to
 214          * fetch all of a given page's revisions in turn.
 215          * Each row can be fed to the constructor to get objects.
 216          *
 217          * @param $title Title
 218          * @return ResultWrapper
 219          */
 220         public static function fetchRevision( $title ) {
 221                 return Revision::fetchFromConds(
 222                         wfGetDB( DB_SLAVE ),
 223                         array( 'rev_id=page_latest',
 224                                    'page_namespace' => $title->getNamespace(),
 225                                    'page_title'     => $title->getDBkey(),
 226                                    'page_id=rev_page' ) );
 227         }
 228
 229         /**
 230          * Given a set of conditions, return a ResultWrapper
 231          * which will return matching database rows with the
 232          * fields necessary to build Revision objects.
 233          *
 234          * @param $db DatabaseBase
 235          * @param $conditions Array
 236          * @return ResultWrapper
 237          */
 238         private static function fetchFromConds( $db, $conditions ) {
 239                 $fields = self::selectFields();
 240                 $fields[] = 'page_namespace';
 241                 $fields[] = 'page_title';
 242                 $fields[] = 'page_latest';
 243                 return $db->select(
 244                         array( 'page', 'revision' ),
 245                         $fields,
 246                         $conditions,
 247                         __METHOD__,
 248                         array( 'LIMIT' => 1 ) );
 249         }
 250
 251         /**
 252          * Return the list of revision fields that should be selected to create
 253          * a new revision.
 254          */
 255         public static function selectFields() {
 256                 return array(
 257                         'rev_id',
 258                         'rev_page',
 259                         'rev_text_id',
 260                         'rev_timestamp',
 261                         'rev_comment',
 262                         'rev_user_text,'.
 263                         'rev_user',
 264                         'rev_minor_edit',
 265                         'rev_deleted',
 266                         'rev_len',
 267                         'rev_parent_id'
 268                 );
 269         }
 270
 271         /**
 272          * Return the list of text fields that should be selected to read the
 273          * revision text
 274          */
 275         static function selectTextFields() {
 276                 return array(
 277                         'old_text',
 278                         'old_flags'
 279                 );
 280         }
 281
 282         /**
 283          * Return the list of page fields that should be selected from page table
 284          */
 285         static function selectPageFields() {
 286                 return array(
 287                         'page_namespace',
 288                         'page_title',
 289                         'page_latest'
 290                 );
 291         }
 292
 293         /**
 294          * Constructor
 295          *
 296          * @param $row Mixed: either a database row or an array
 297          * @access private
 298          */
 299         function __construct( $row ) {
 300                 if( is_object( $row ) ) {
 301                         $this->mId        = intval( $row->rev_id );
 302                         $this->mPage      = intval( $row->rev_page );
 303                         $this->mTextId    = intval( $row->rev_text_id );
 304                         $this->mComment   =         $row->rev_comment;
 305                         $this->mUserText  =         $row->rev_user_text;
 306                         $this->mUser      = intval( $row->rev_user );
 307                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 308                         $this->mTimestamp =         $row->rev_timestamp;
 309                         $this->mDeleted   = intval( $row->rev_deleted );
 310
 311                         if( !isset( $row->rev_parent_id ) )
 312                                 $this->mParentId = is_null($row->rev_parent_id) ? null : 0;
 313                         else
 314                                 $this->mParentId  = intval( $row->rev_parent_id );
 315
 316                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) )
 317                                 $this->mSize = null;
 318                         else
 319                                 $this->mSize = intval( $row->rev_len );
 320
 321                         if( isset( $row->page_latest ) ) {
 322                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 323                                 $this->mTitle = Title::newFromRow( $row );
 324                         } else {
 325                                 $this->mCurrent = false;
 326                                 $this->mTitle = null;
 327                         }
 328
 329                         // Lazy extraction...
 330                         $this->mText      = null;
 331                         if( isset( $row->old_text ) ) {
 332                                 $this->mTextRow = $row;
 333                         } else {
 334                                 // 'text' table row entry will be lazy-loaded
 335                                 $this->mTextRow = null;
 336                         }
 337                 } elseif( is_array( $row ) ) {
 338                         // Build a new revision to be saved...
 339                         global $wgUser;
 340
 341                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 342                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 343                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 344                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 345                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 346                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 347                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 348                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 349                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 350                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 351
 352                         // Enforce spacing trimming on supplied text
 353                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 354                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 355                         $this->mTextRow   = null;
 356
 357                         $this->mTitle     = null; # Load on demand if needed
 358                         $this->mCurrent   = false;
 359                         # If we still have no len_size, see it we have the text to figure it out
 360                         if ( !$this->mSize )
 361                                 $this->mSize      = is_null( $this->mText ) ? null : strlen( $this->mText );
 362                 } else {
 363                         throw new MWException( 'Revision constructor passed invalid row format.' );
 364                 }
 365                 $this->mUnpatrolled = null;
 366         }
 367
 368         /**
 369          * Get revision ID
 370          *
 371          * @return Integer
 372          */
 373         public function getId() {
 374                 return $this->mId;
 375         }
 376
 377         /**
 378          * Get text row ID
 379          *
 380          * @return Integer
 381          */
 382         public function getTextId() {
 383                 return $this->mTextId;
 384         }
 385
 386         /**
 387          * Get parent revision ID (the original previous page revision)
 388          *
 389          * @return Integer
 390          */
 391         public function getParentId() {
 392                 return $this->mParentId;
 393         }
 394
 395         /**
 396          * Returns the length of the text in this revision, or null if unknown.
 397          *
 398          * @return Integer
 399          */
 400         public function getSize() {
 401                 return $this->mSize;
 402         }
 403
 404         /**
 405          * Returns the title of the page associated with this entry.
 406          *
 407          * @return Title
 408          */
 409         public function getTitle() {
 410                 if( isset( $this->mTitle ) ) {
 411                         return $this->mTitle;
 412                 }
 413                 $dbr = wfGetDB( DB_SLAVE );
 414                 $row = $dbr->selectRow(
 415                         array( 'page', 'revision' ),
 416                         array( 'page_namespace', 'page_title' ),
 417                         array( 'page_id=rev_page',
 418                                    'rev_id' => $this->mId ),
 419                         'Revision::getTitle' );
 420                 if( $row ) {
 421                         $this->mTitle = Title::makeTitle( $row->page_namespace,
 422                                                                                           $row->page_title );
 423                 }
 424                 return $this->mTitle;
 425         }
 426
 427         /**
 428          * Set the title of the revision
 429          *
 430          * @param $title Title
 431          */
 432         public function setTitle( $title ) {
 433                 $this->mTitle = $title;
 434         }
 435
 436         /**
 437          * Get the page ID
 438          *
 439          * @return Integer
 440          */
 441         public function getPage() {
 442                 return $this->mPage;
 443         }
 444
 445         /**
 446          * Fetch revision's user id if it's available to the specified audience.
 447          * If the specified audience does not have access to it, zero will be
 448          * returned.
 449          *
 450          * @param $audience Integer: one of:
 451          *      Revision::FOR_PUBLIC       to be displayed to all users
 452          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 453          *      Revision::RAW              get the ID regardless of permissions
 454          *
 455          *
 456          * @return Integer
 457          */
 458         public function getUser( $audience = self::FOR_PUBLIC ) {
 459                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 460                         return 0;
 461                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 462                         return 0;
 463                 } else {
 464                         return $this->mUser;
 465                 }
 466         }
 467
 468         /**
 469          * Fetch revision's user id without regard for the current user's permissions
 470          *
 471          * @return String
 472          */
 473         public function getRawUser() {
 474                 return $this->mUser;
 475         }
 476
 477         /**
 478          * Fetch revision's username if it's available to the specified audience.
 479          * If the specified audience does not have access to the username, an
 480          * empty string will be returned.
 481          *
 482          * @param $audience Integer: one of:
 483          *      Revision::FOR_PUBLIC       to be displayed to all users
 484          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 485          *      Revision::RAW              get the text regardless of permissions
 486          *
 487          * @return string
 488          */
 489         public function getUserText( $audience = self::FOR_PUBLIC ) {
 490                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 491                         return '';
 492                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 493                         return '';
 494                 } else {
 495                         return $this->mUserText;
 496                 }
 497         }
 498
 499         /**
 500          * Fetch revision's username without regard for view restrictions
 501          *
 502          * @return String
 503          */
 504         public function getRawUserText() {
 505                 return $this->mUserText;
 506         }
 507
 508         /**
 509          * Fetch revision comment if it's available to the specified audience.
 510          * If the specified audience does not have access to the comment, an
 511          * empty string will be returned.
 512          *
 513          * @param $audience Integer: one of:
 514          *      Revision::FOR_PUBLIC       to be displayed to all users
 515          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 516          *      Revision::RAW              get the text regardless of permissions
 517          *
 518          * @return String
 519          */
 520         function getComment( $audience = self::FOR_PUBLIC ) {
 521                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 522                         return '';
 523                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT ) ) {
 524                         return '';
 525                 } else {
 526                         return $this->mComment;
 527                 }
 528         }
 529
 530         /**
 531          * Fetch revision comment without regard for the current user's permissions
 532          *
 533          * @return String
 534          */
 535         public function getRawComment() {
 536                 return $this->mComment;
 537         }
 538
 539         /**
 540          * @return Boolean
 541          */
 542         public function isMinor() {
 543                 return (bool)$this->mMinorEdit;
 544         }
 545
 546         /**
 547          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 548          */
 549         public function isUnpatrolled() {
 550                 if( $this->mUnpatrolled !== null ) {
 551                         return $this->mUnpatrolled;
 552                 }
 553                 $dbr = wfGetDB( DB_SLAVE );
 554                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 555                         'rc_id',
 556                         array( // Add redundant user,timestamp condition so we can use the existing index
 557                                 'rc_user_text'  => $this->getRawUserText(),
 558                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 559                                 'rc_this_oldid' => $this->getId(),
 560                                 'rc_patrolled'  => 0
 561                         ),
 562                         __METHOD__
 563                 );
 564                 return (int)$this->mUnpatrolled;
 565         }
 566
 567         /**
 568          * int $field one of DELETED_* bitfield constants
 569          *
 570          * @return Boolean
 571          */
 572         public function isDeleted( $field ) {
 573                 return ( $this->mDeleted & $field ) == $field;
 574         }
 575
 576         /**
 577          * Get the deletion bitfield of the revision
 578          */
 579         public function getVisibility() {
 580                 return (int)$this->mDeleted;
 581         }
 582
 583         /**
 584          * Fetch revision text if it's available to the specified audience.
 585          * If the specified audience does not have the ability to view this
 586          * revision, an empty string will be returned.
 587          *
 588          * @param $audience Integer: one of:
 589          *      Revision::FOR_PUBLIC       to be displayed to all users
 590          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 591          *      Revision::RAW              get the text regardless of permissions
 592          *
 593          * @return String
 594          */
 595         public function getText( $audience = self::FOR_PUBLIC ) {
 596                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 597                         return '';
 598                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT ) ) {
 599                         return '';
 600                 } else {
 601                         return $this->getRawText();
 602                 }
 603         }
 604
 605         /**
 606          * Alias for getText(Revision::FOR_THIS_USER)
 607          *
 608          * @deprecated since 1.17
 609          * @return String
 610          */
 611         public function revText() {
 612                 wfDeprecated( __METHOD__ );
 613                 return $this->getText( self::FOR_THIS_USER );
 614         }
 615
 616         /**
 617          * Fetch revision text without regard for view restrictions
 618          *
 619          * @return String
 620          */
 621         public function getRawText() {
 622                 if( is_null( $this->mText ) ) {
 623                         // Revision text is immutable. Load on demand:
 624                         $this->mText = $this->loadText();
 625                 }
 626                 return $this->mText;
 627         }
 628
 629         /**
 630          * @return String
 631          */
 632         public function getTimestamp() {
 633                 return wfTimestamp( TS_MW, $this->mTimestamp );
 634         }
 635
 636         /**
 637          * @return Boolean
 638          */
 639         public function isCurrent() {
 640                 return $this->mCurrent;
 641         }
 642
 643         /**
 644          * Get previous revision for this title
 645          *
 646          * @return Revision or null
 647          */
 648         public function getPrevious() {
 649                 if( $this->getTitle() ) {
 650                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 651                         if( $prev ) {
 652                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 653                         }
 654                 }
 655                 return null;
 656         }
 657
 658         /**
 659          * Get next revision for this title
 660          *
 661          * @return Revision or null
 662          */
 663         public function getNext() {
 664                 if( $this->getTitle() ) {
 665                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 666                         if ( $next ) {
 667                                 return Revision::newFromTitle( $this->getTitle(), $next );
 668                         }
 669                 }
 670                 return null;
 671         }
 672
 673         /**
 674          * Get previous revision Id for this page_id
 675          * This is used to populate rev_parent_id on save
 676          *
 677          * @param $db DatabaseBase
 678          * @return Integer
 679          */
 680         private function getPreviousRevisionId( $db ) {
 681                 if( is_null( $this->mPage ) ) {
 682                         return 0;
 683                 }
 684                 # Use page_latest if ID is not given
 685                 if( !$this->mId ) {
 686                         $prevId = $db->selectField( 'page', 'page_latest',
 687                                 array( 'page_id' => $this->mPage ),
 688                                 __METHOD__ );
 689                 } else {
 690                         $prevId = $db->selectField( 'revision', 'rev_id',
 691                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 692                                 __METHOD__,
 693                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 694                 }
 695                 return intval( $prevId );
 696         }
 697
 698         /**
 699           * Get revision text associated with an old or archive row
 700           * $row is usually an object from wfFetchRow(), both the flags and the text
 701           * field must be included
 702           *
 703           * @param $row Object: the text data
 704           * @param $prefix String: table prefix (default 'old_')
 705           * @return String: text the text requested or false on failure
 706           */
 707         public static function getRevisionText( $row, $prefix = 'old_' ) {
 708                 wfProfileIn( __METHOD__ );
 709
 710                 # Get data
 711                 $textField = $prefix . 'text';
 712                 $flagsField = $prefix . 'flags';
 713
 714                 if( isset( $row->$flagsField ) ) {
 715                         $flags = explode( ',', $row->$flagsField );
 716                 } else {
 717                         $flags = array();
 718                 }
 719
 720                 if( isset( $row->$textField ) ) {
 721                         $text = $row->$textField;
 722                 } else {
 723                         wfProfileOut( __METHOD__ );
 724                         return false;
 725                 }
 726
 727                 # Use external methods for external objects, text in table is URL-only then
 728                 if ( in_array( 'external', $flags ) ) {
 729                         $url = $text;
 730                         @list(/* $proto */, $path ) = explode( '://', $url, 2 );
 731                         if( $path == '' ) {
 732                                 wfProfileOut( __METHOD__ );
 733                                 return false;
 734                         }
 735                         $text = ExternalStore::fetchFromURL( $url );
 736                 }
 737
 738                 // If the text was fetched without an error, convert it
 739                 if ( $text !== false ) {
 740                         if( in_array( 'gzip', $flags ) ) {
 741                                 # Deal with optional compression of archived pages.
 742                                 # This can be done periodically via maintenance/compressOld.php, and
 743                                 # as pages are saved if $wgCompressRevisions is set.
 744                                 $text = gzinflate( $text );
 745                         }
 746
 747                         if( in_array( 'object', $flags ) ) {
 748                                 # Generic compressed storage
 749                                 $obj = unserialize( $text );
 750                                 if ( !is_object( $obj ) ) {
 751                                         // Invalid object
 752                                         wfProfileOut( __METHOD__ );
 753                                         return false;
 754                                 }
 755                                 $text = $obj->getText();
 756                         }
 757
 758                         global $wgLegacyEncoding;
 759                         if( $text !== false && $wgLegacyEncoding
 760                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
 761                         {
 762                                 # Old revisions kept around in a legacy encoding?
 763                                 # Upconvert on demand.
 764                                 # ("utf8" checked for compatibility with some broken
 765                                 #  conversion scripts 2008-12-30)
 766                                 global $wgContLang;
 767                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
 768                         }
 769                 }
 770                 wfProfileOut( __METHOD__ );
 771                 return $text;
 772         }
 773
 774         /**
 775          * If $wgCompressRevisions is enabled, we will compress data.
 776          * The input string is modified in place.
 777          * Return value is the flags field: contains 'gzip' if the
 778          * data is compressed, and 'utf-8' if we're saving in UTF-8
 779          * mode.
 780          *
 781          * @param $text Mixed: reference to a text
 782          * @return String
 783          */
 784         public static function compressRevisionText( &$text ) {
 785                 global $wgCompressRevisions;
 786                 $flags = array();
 787
 788                 # Revisions not marked this way will be converted
 789                 # on load if $wgLegacyCharset is set in the future.
 790                 $flags[] = 'utf-8';
 791
 792                 if( $wgCompressRevisions ) {
 793                         if( function_exists( 'gzdeflate' ) ) {
 794                                 $text = gzdeflate( $text );
 795                                 $flags[] = 'gzip';
 796                         } else {
 797                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 798                         }
 799                 }
 800                 return implode( ',', $flags );
 801         }
 802
 803         /**
 804          * Insert a new revision into the database, returning the new revision ID
 805          * number on success and dies horribly on failure.
 806          *
 807          * @param $dbw DatabaseBase: (master connection)
 808          * @return Integer
 809          */
 810         public function insertOn( $dbw ) {
 811                 global $wgDefaultExternalStore;
 812
 813                 wfProfileIn( __METHOD__ );
 814
 815                 $data = $this->mText;
 816                 $flags = Revision::compressRevisionText( $data );
 817
 818                 # Write to external storage if required
 819                 if( $wgDefaultExternalStore ) {
 820                         // Store and get the URL
 821                         $data = ExternalStore::insertToDefault( $data );
 822                         if( !$data ) {
 823                                 throw new MWException( "Unable to store text to external storage" );
 824                         }
 825                         if( $flags ) {
 826                                 $flags .= ',';
 827                         }
 828                         $flags .= 'external';
 829                 }
 830
 831                 # Record the text (or external storage URL) to the text table
 832                 if( !isset( $this->mTextId ) ) {
 833                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
 834                         $dbw->insert( 'text',
 835                                 array(
 836                                         'old_id'    => $old_id,
 837                                         'old_text'  => $data,
 838                                         'old_flags' => $flags,
 839                                 ), __METHOD__
 840                         );
 841                         $this->mTextId = $dbw->insertId();
 842                 }
 843
 844                 if ( $this->mComment === null ) $this->mComment = "";
 845
 846                 # Record the edit in revisions
 847                 $rev_id = isset( $this->mId )
 848                         ? $this->mId
 849                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
 850                 $dbw->insert( 'revision',
 851                         array(
 852                                 'rev_id'         => $rev_id,
 853                                 'rev_page'       => $this->mPage,
 854                                 'rev_text_id'    => $this->mTextId,
 855                                 'rev_comment'    => $this->mComment,
 856                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 857                                 'rev_user'       => $this->mUser,
 858                                 'rev_user_text'  => $this->mUserText,
 859                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 860                                 'rev_deleted'    => $this->mDeleted,
 861                                 'rev_len'        => $this->mSize,
 862                                 'rev_parent_id'  => is_null($this->mParentId) ?
 863                                         $this->getPreviousRevisionId( $dbw ) : $this->mParentId
 864                         ), __METHOD__
 865                 );
 866
 867                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
 868
 869                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 870
 871                 wfProfileOut( __METHOD__ );
 872                 return $this->mId;
 873         }
 874
 875         /**
 876          * Lazy-load the revision's text.
 877          * Currently hardcoded to the 'text' table storage engine.
 878          *
 879          * @return String
 880          */
 881         protected function loadText() {
 882                 wfProfileIn( __METHOD__ );
 883
 884                 // Caching may be beneficial for massive use of external storage
 885                 global $wgRevisionCacheExpiry, $wgMemc;
 886                 $textId = $this->getTextId();
 887                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
 888                 if( $wgRevisionCacheExpiry ) {
 889                         $text = $wgMemc->get( $key );
 890                         if( is_string( $text ) ) {
 891                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
 892                                 wfProfileOut( __METHOD__ );
 893                                 return $text;
 894                         }
 895                 }
 896
 897                 // If we kept data for lazy extraction, use it now...
 898                 if ( isset( $this->mTextRow ) ) {
 899                         $row = $this->mTextRow;
 900                         $this->mTextRow = null;
 901                 } else {
 902                         $row = null;
 903                 }
 904
 905                 if( !$row ) {
 906                         // Text data is immutable; check slaves first.
 907                         $dbr = wfGetDB( DB_SLAVE );
 908                         $row = $dbr->selectRow( 'text',
 909                                 array( 'old_text', 'old_flags' ),
 910                                 array( 'old_id' => $this->getTextId() ),
 911                                 __METHOD__ );
 912                 }
 913
 914                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
 915                         // Possible slave lag!
 916                         $dbw = wfGetDB( DB_MASTER );
 917                         $row = $dbw->selectRow( 'text',
 918                                 array( 'old_text', 'old_flags' ),
 919                                 array( 'old_id' => $this->getTextId() ),
 920                                 __METHOD__ );
 921                 }
 922
 923                 $text = self::getRevisionText( $row );
 924
 925                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
 926                 if( $wgRevisionCacheExpiry && $text !== false ) {
 927                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 928                 }
 929
 930                 wfProfileOut( __METHOD__ );
 931
 932                 return $text;
 933         }
 934
 935         /**
 936          * Create a new null-revision for insertion into a page's
 937          * history. This will not re-save the text, but simply refer
 938          * to the text from the previous version.
 939          *
 940          * Such revisions can for instance identify page rename
 941          * operations and other such meta-modifications.
 942          *
 943          * @param $dbw DatabaseBase
 944          * @param $pageId Integer: ID number of the page to read from
 945          * @param $summary String: revision's summary
 946          * @param $minor Boolean: whether the revision should be considered as minor
 947          * @return Revision|null on error
 948          */
 949         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
 950                 wfProfileIn( __METHOD__ );
 951
 952                 $current = $dbw->selectRow(
 953                         array( 'page', 'revision' ),
 954                         array( 'page_latest', 'rev_text_id', 'rev_len' ),
 955                         array(
 956                                 'page_id' => $pageId,
 957                                 'page_latest=rev_id',
 958                                 ),
 959                         __METHOD__ );
 960
 961                 if( $current ) {
 962                         $revision = new Revision( array(
 963                                 'page'       => $pageId,
 964                                 'comment'    => $summary,
 965                                 'minor_edit' => $minor,
 966                                 'text_id'    => $current->rev_text_id,
 967                                 'parent_id'  => $current->page_latest,
 968                                 'len'        => $current->rev_len
 969                                 ) );
 970                 } else {
 971                         $revision = null;
 972                 }
 973
 974                 wfProfileOut( __METHOD__ );
 975                 return $revision;
 976         }
 977
 978         /**
 979          * Determine if the current user is allowed to view a particular
 980          * field of this revision, if it's marked as deleted.
 981          *
 982          * @param $field Integer:one of self::DELETED_TEXT,
 983          *                              self::DELETED_COMMENT,
 984          *                              self::DELETED_USER
 985          * @return Boolean
 986          */
 987         public function userCan( $field ) {
 988                 return self::userCanBitfield( $this->mDeleted, $field );
 989         }
 990
 991         /**
 992          * Determine if the current user is allowed to view a particular
 993          * field of this revision, if it's marked as deleted. This is used
 994          * by various classes to avoid duplication.
 995          *
 996          * @param $bitfield Integer: current field
 997          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
 998          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
 999          *                               self::DELETED_USER = File::DELETED_USER
1000          * @return Boolean
1001          */
1002         public static function userCanBitfield( $bitfield, $field ) {
1003                 if( $bitfield & $field ) { // aspect is deleted
1004                         global $wgUser;
1005                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1006                                 $permission = 'suppressrevision';
1007                         } elseif ( $field & self::DELETED_TEXT ) {
1008                                 $permission = 'deletedtext';
1009                         } else {
1010                                 $permission = 'deletedhistory';
1011                         }
1012                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1013                         return $wgUser->isAllowed( $permission );
1014                 } else {
1015                         return true;
1016                 }
1017         }
1018
1019         /**
1020          * Get rev_timestamp from rev_id, without loading the rest of the row
1021          *
1022          * @param $title Title
1023          * @param $id Integer
1024          * @return String
1025          */
1026         static function getTimestampFromId( $title, $id ) {
1027                 $dbr = wfGetDB( DB_SLAVE );
1028                 // Casting fix for DB2
1029                 if ( $id == '' ) {
1030                         $id = 0;
1031                 }
1032                 $conds = array( 'rev_id' => $id );
1033                 $conds['rev_page'] = $title->getArticleId();
1034                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1035                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1036                         # Not in slave, try master
1037                         $dbw = wfGetDB( DB_MASTER );
1038                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1039                 }
1040                 return wfTimestamp( TS_MW, $timestamp );
1041         }
1042
1043         /**
1044          * Get count of revisions per page...not very efficient
1045          *
1046          * @param $db DatabaseBase
1047          * @param $id Integer: page id
1048          * @return Integer
1049          */
1050         static function countByPageId( $db, $id ) {
1051                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1052                         array( 'rev_page' => $id ), __METHOD__ );
1053                 if( $row ) {
1054                         return $row->revCount;
1055                 }
1056                 return 0;
1057         }
1058
1059         /**
1060          * Get count of revisions per page...not very efficient
1061          *
1062          * @param $db DatabaseBase
1063          * @param $title Title
1064          * @return Integer
1065          */
1066         static function countByTitle( $db, $title ) {
1067                 $id = $title->getArticleId();
1068                 if( $id ) {
1069                         return Revision::countByPageId( $db, $id );
1070                 }
1071                 return 0;
1072         }
1073 }
1074
1075 /**
1076  * Aliases for backwards compatibility with 1.6
1077  */
1078 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
1079 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
1080 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
1081 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );