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 (optional)
  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                                 return null; // page does not exist
  54                         }
  55                         $conds['rev_id'] = $latest;
  56                 } else {
  57                         // Use a join to get the latest revision
  58                         $conds[] = 'rev_id=page_latest';
  59                 }
  60                 $conds[] = 'page_id=rev_page';
  61                 return Revision::newFromConds( $conds );
  62         }
  63
  64         /**
  65          * Load either the current, or a specified, revision
  66          * that's attached to a given page ID.
  67          * Returns null if no such revision can be found.
  68          *
  69          * @param $revId Integer
  70          * @param $pageId Integer (optional)
  71          * @return Revision or null
  72          */
  73         public static function newFromPageId( $pageId, $revId = 0 ) {
  74                 $conds = array( 'page_id' => $pageId );
  75                 if ( $revId ) {
  76                         $conds['rev_id'] = $revId;
  77                 } elseif ( wfGetLB()->getServerCount() > 1 ) {
  78                         // Get the latest revision ID from the master
  79                         $dbw = wfGetDB( DB_MASTER );
  80                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
  81                         if ( $latest === false ) {
  82                                 return null; // page does not exist
  83                         }
  84                         $conds['rev_id'] = $latest;
  85                 } else {
  86                         $conds[] = 'rev_id = page_latest';
  87                 }
  88                 $conds[] = 'page_id=rev_page';
  89                 return Revision::newFromConds( $conds );
  90         }
  91
  92         /**
  93          * Make a fake revision object from an archive table row. This is queried
  94          * for permissions or even inserted (as in Special:Undelete)
  95          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
  96          *
  97          * @param $row
  98          * @param $overrides array
  99          *
 100          * @return Revision
 101          */
 102         public static function newFromArchiveRow( $row, $overrides = array() ) {
 103                 $attribs = $overrides + array(
 104                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 105                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 106                         'comment'    => $row->ar_comment,
 107                         'user'       => $row->ar_user,
 108                         'user_text'  => $row->ar_user_text,
 109                         'timestamp'  => $row->ar_timestamp,
 110                         'minor_edit' => $row->ar_minor_edit,
 111                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 112                         'deleted'    => $row->ar_deleted,
 113                         'len'        => $row->ar_len);
 114                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 115                         // Pre-1.5 ar_text row
 116                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 117                         if ( $attribs['text'] === false ) {
 118                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 119                         }
 120                 }
 121                 return new self( $attribs );
 122         }
 123
 124         /**
 125          * Load a page revision from a given revision ID number.
 126          * Returns null if no such revision can be found.
 127          *
 128          * @param $db DatabaseBase
 129          * @param $id Integer
 130          * @return Revision or null
 131          */
 132         public static function loadFromId( $db, $id ) {
 133                 return Revision::loadFromConds( $db,
 134                         array( 'page_id=rev_page',
 135                                    'rev_id' => intval( $id ) ) );
 136         }
 137
 138         /**
 139          * Load either the current, or a specified, revision
 140          * that's attached to a given page. If not attached
 141          * to that page, will return null.
 142          *
 143          * @param $db DatabaseBase
 144          * @param $pageid Integer
 145          * @param $id Integer
 146          * @return Revision or null
 147          */
 148         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 149                 $conds = array( 'page_id=rev_page','rev_page' => intval( $pageid ), 'page_id'=>intval( $pageid ) );
 150                 if( $id ) {
 151                         $conds['rev_id'] = intval( $id );
 152                 } else {
 153                         $conds[] = 'rev_id=page_latest';
 154                 }
 155                 return Revision::loadFromConds( $db, $conds );
 156         }
 157
 158         /**
 159          * Load either the current, or a specified, revision
 160          * that's attached to a given page. If not attached
 161          * to that page, will return null.
 162          *
 163          * @param $db DatabaseBase
 164          * @param $title Title
 165          * @param $id Integer
 166          * @return Revision or null
 167          */
 168         public static function loadFromTitle( $db, $title, $id = 0 ) {
 169                 if( $id ) {
 170                         $matchId = intval( $id );
 171                 } else {
 172                         $matchId = 'page_latest';
 173                 }
 174                 return Revision::loadFromConds(
 175                         $db,
 176                         array( "rev_id=$matchId",
 177                                    'page_id=rev_page',
 178                                    'page_namespace' => $title->getNamespace(),
 179                                    'page_title'     => $title->getDBkey() ) );
 180         }
 181
 182         /**
 183          * Load the revision for the given title with the given timestamp.
 184          * WARNING: Timestamps may in some circumstances not be unique,
 185          * so this isn't the best key to use.
 186          *
 187          * @param $db DatabaseBase
 188          * @param $title Title
 189          * @param $timestamp String
 190          * @return Revision or null
 191          */
 192         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 193                 return Revision::loadFromConds(
 194                         $db,
 195                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 196                                    'page_id=rev_page',
 197                                    'page_namespace' => $title->getNamespace(),
 198                                    'page_title'     => $title->getDBkey() ) );
 199         }
 200
 201         /**
 202          * Given a set of conditions, fetch a revision.
 203          *
 204          * @param $conditions Array
 205          * @return Revision or null
 206          */
 207         public static function newFromConds( $conditions ) {
 208                 $db = wfGetDB( DB_SLAVE );
 209                 $row = Revision::loadFromConds( $db, $conditions );
 210                 if( is_null( $row ) && wfGetLB()->getServerCount() > 1 ) {
 211                         $dbw = wfGetDB( DB_MASTER );
 212                         $row = Revision::loadFromConds( $dbw, $conditions );
 213                 }
 214                 return $row;
 215         }
 216
 217         /**
 218          * Given a set of conditions, fetch a revision from
 219          * the given database connection.
 220          *
 221          * @param $db DatabaseBase
 222          * @param $conditions Array
 223          * @return Revision or null
 224          */
 225         private static function loadFromConds( $db, $conditions ) {
 226                 $res = Revision::fetchFromConds( $db, $conditions );
 227                 if( $res ) {
 228                         $row = $res->fetchObject();
 229                         $res->free();
 230                         if( $row ) {
 231                                 $ret = new Revision( $row );
 232                                 return $ret;
 233                         }
 234                 }
 235                 $ret = null;
 236                 return $ret;
 237         }
 238
 239         /**
 240          * Return a wrapper for a series of database rows to
 241          * fetch all of a given page's revisions in turn.
 242          * Each row can be fed to the constructor to get objects.
 243          *
 244          * @param $title Title
 245          * @return ResultWrapper
 246          */
 247         public static function fetchRevision( $title ) {
 248                 return Revision::fetchFromConds(
 249                         wfGetDB( DB_SLAVE ),
 250                         array( 'rev_id=page_latest',
 251                                    'page_namespace' => $title->getNamespace(),
 252                                    'page_title'     => $title->getDBkey(),
 253                                    'page_id=rev_page' ) );
 254         }
 255
 256         /**
 257          * Given a set of conditions, return a ResultWrapper
 258          * which will return matching database rows with the
 259          * fields necessary to build Revision objects.
 260          *
 261          * @param $db DatabaseBase
 262          * @param $conditions Array
 263          * @return ResultWrapper
 264          */
 265         private static function fetchFromConds( $db, $conditions ) {
 266                 $fields = self::selectFields();
 267                 $fields[] = 'page_namespace';
 268                 $fields[] = 'page_title';
 269                 $fields[] = 'page_latest';
 270                 return $db->select(
 271                         array( 'page', 'revision' ),
 272                         $fields,
 273                         $conditions,
 274                         __METHOD__,
 275                         array( 'LIMIT' => 1 ) );
 276         }
 277
 278         /**
 279          * Return the list of revision fields that should be selected to create
 280          * a new revision.
 281          */
 282         public static function selectFields() {
 283                 return array(
 284                         'rev_id',
 285                         'rev_page',
 286                         'rev_text_id',
 287                         'rev_timestamp',
 288                         'rev_comment',
 289                         'rev_user_text,'.
 290                         'rev_user',
 291                         'rev_minor_edit',
 292                         'rev_deleted',
 293                         'rev_len',
 294                         'rev_parent_id'
 295                 );
 296         }
 297
 298         /**
 299          * Return the list of text fields that should be selected to read the
 300          * revision text
 301          */
 302         static function selectTextFields() {
 303                 return array(
 304                         'old_text',
 305                         'old_flags'
 306                 );
 307         }
 308
 309         /**
 310          * Return the list of page fields that should be selected from page table
 311          */
 312         static function selectPageFields() {
 313                 return array(
 314                         'page_namespace',
 315                         'page_title',
 316                         'page_latest'
 317                 );
 318         }
 319
 320         /**
 321          * Constructor
 322          *
 323          * @param $row Mixed: either a database row or an array
 324          * @access private
 325          */
 326         function __construct( $row ) {
 327                 if( is_object( $row ) ) {
 328                         $this->mId        = intval( $row->rev_id );
 329                         $this->mPage      = intval( $row->rev_page );
 330                         $this->mTextId    = intval( $row->rev_text_id );
 331                         $this->mComment   =         $row->rev_comment;
 332                         $this->mUserText  =         $row->rev_user_text;
 333                         $this->mUser      = intval( $row->rev_user );
 334                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 335                         $this->mTimestamp =         $row->rev_timestamp;
 336                         $this->mDeleted   = intval( $row->rev_deleted );
 337
 338                         if( !isset( $row->rev_parent_id ) ) {
 339                                 $this->mParentId = is_null($row->rev_parent_id) ? null : 0;
 340                         } else {
 341                                 $this->mParentId  = intval( $row->rev_parent_id );
 342                         }
 343
 344                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) ) {
 345                                 $this->mSize = null;
 346                         } else {
 347                                 $this->mSize = intval( $row->rev_len );
 348                         }
 349
 350                         if( isset( $row->page_latest ) ) {
 351                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 352                                 $this->mTitle = Title::newFromRow( $row );
 353                         } else {
 354                                 $this->mCurrent = false;
 355                                 $this->mTitle = null;
 356                         }
 357
 358                         // Lazy extraction...
 359                         $this->mText      = null;
 360                         if( isset( $row->old_text ) ) {
 361                                 $this->mTextRow = $row;
 362                         } else {
 363                                 // 'text' table row entry will be lazy-loaded
 364                                 $this->mTextRow = null;
 365                         }
 366                 } elseif( is_array( $row ) ) {
 367                         // Build a new revision to be saved...
 368                         global $wgUser;
 369
 370                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 371                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 372                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 373                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 374                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 375                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 376                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 377                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 378                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 379                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 380
 381                         // Enforce spacing trimming on supplied text
 382                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 383                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 384                         $this->mTextRow   = null;
 385
 386                         $this->mTitle     = null; # Load on demand if needed
 387                         $this->mCurrent   = false;
 388                         # If we still have no len_size, see it we have the text to figure it out
 389                         if ( !$this->mSize )
 390                                 $this->mSize      = is_null( $this->mText ) ? null : strlen( $this->mText );
 391                 } else {
 392                         throw new MWException( 'Revision constructor passed invalid row format.' );
 393                 }
 394                 $this->mUnpatrolled = null;
 395         }
 396
 397         /**
 398          * Get revision ID
 399          *
 400          * @return Integer
 401          */
 402         public function getId() {
 403                 return $this->mId;
 404         }
 405
 406         /**
 407          * Get text row ID
 408          *
 409          * @return Integer
 410          */
 411         public function getTextId() {
 412                 return $this->mTextId;
 413         }
 414
 415         /**
 416          * Get parent revision ID (the original previous page revision)
 417          *
 418          * @return Integer
 419          */
 420         public function getParentId() {
 421                 return $this->mParentId;
 422         }
 423
 424         /**
 425          * Returns the length of the text in this revision, or null if unknown.
 426          *
 427          * @return Integer
 428          */
 429         public function getSize() {
 430                 return $this->mSize;
 431         }
 432
 433         /**
 434          * Returns the title of the page associated with this entry.
 435          *
 436          * @return Title
 437          */
 438         public function getTitle() {
 439                 if( isset( $this->mTitle ) ) {
 440                         return $this->mTitle;
 441                 }
 442                 $dbr = wfGetDB( DB_SLAVE );
 443                 $row = $dbr->selectRow(
 444                         array( 'page', 'revision' ),
 445                         array( 'page_namespace', 'page_title' ),
 446                         array( 'page_id=rev_page',
 447                                    'rev_id' => $this->mId ),
 448                         'Revision::getTitle' );
 449                 if( $row ) {
 450                         $this->mTitle = Title::makeTitle( $row->page_namespace, $row->page_title );
 451                 }
 452                 return $this->mTitle;
 453         }
 454
 455         /**
 456          * Set the title of the revision
 457          *
 458          * @param $title Title
 459          */
 460         public function setTitle( $title ) {
 461                 $this->mTitle = $title;
 462         }
 463
 464         /**
 465          * Get the page ID
 466          *
 467          * @return Integer
 468          */
 469         public function getPage() {
 470                 return $this->mPage;
 471         }
 472
 473         /**
 474          * Fetch revision's user id if it's available to the specified audience.
 475          * If the specified audience does not have access to it, zero will be
 476          * returned.
 477          *
 478          * @param $audience Integer: one of:
 479          *      Revision::FOR_PUBLIC       to be displayed to all users
 480          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 481          *      Revision::RAW              get the ID regardless of permissions
 482          *
 483          *
 484          * @return Integer
 485          */
 486         public function getUser( $audience = self::FOR_PUBLIC ) {
 487                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 488                         return 0;
 489                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 490                         return 0;
 491                 } else {
 492                         return $this->mUser;
 493                 }
 494         }
 495
 496         /**
 497          * Fetch revision's user id without regard for the current user's permissions
 498          *
 499          * @return String
 500          */
 501         public function getRawUser() {
 502                 return $this->mUser;
 503         }
 504
 505         /**
 506          * Fetch revision's username if it's available to the specified audience.
 507          * If the specified audience does not have access to the username, an
 508          * empty string will be returned.
 509          *
 510          * @param $audience Integer: one of:
 511          *      Revision::FOR_PUBLIC       to be displayed to all users
 512          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 513          *      Revision::RAW              get the text regardless of permissions
 514          *
 515          * @return string
 516          */
 517         public function getUserText( $audience = self::FOR_PUBLIC ) {
 518                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 519                         return '';
 520                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 521                         return '';
 522                 } else {
 523                         return $this->mUserText;
 524                 }
 525         }
 526
 527         /**
 528          * Fetch revision's username without regard for view restrictions
 529          *
 530          * @return String
 531          */
 532         public function getRawUserText() {
 533                 return $this->mUserText;
 534         }
 535
 536         /**
 537          * Fetch revision comment if it's available to the specified audience.
 538          * If the specified audience does not have access to the comment, an
 539          * empty string will be returned.
 540          *
 541          * @param $audience Integer: one of:
 542          *      Revision::FOR_PUBLIC       to be displayed to all users
 543          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 544          *      Revision::RAW              get the text regardless of permissions
 545          *
 546          * @return String
 547          */
 548         function getComment( $audience = self::FOR_PUBLIC ) {
 549                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 550                         return '';
 551                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT ) ) {
 552                         return '';
 553                 } else {
 554                         return $this->mComment;
 555                 }
 556         }
 557
 558         /**
 559          * Fetch revision comment without regard for the current user's permissions
 560          *
 561          * @return String
 562          */
 563         public function getRawComment() {
 564                 return $this->mComment;
 565         }
 566
 567         /**
 568          * @return Boolean
 569          */
 570         public function isMinor() {
 571                 return (bool)$this->mMinorEdit;
 572         }
 573
 574         /**
 575          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 576          */
 577         public function isUnpatrolled() {
 578                 if( $this->mUnpatrolled !== null ) {
 579                         return $this->mUnpatrolled;
 580                 }
 581                 $dbr = wfGetDB( DB_SLAVE );
 582                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 583                         'rc_id',
 584                         array( // Add redundant user,timestamp condition so we can use the existing index
 585                                 'rc_user_text'  => $this->getRawUserText(),
 586                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 587                                 'rc_this_oldid' => $this->getId(),
 588                                 'rc_patrolled'  => 0
 589                         ),
 590                         __METHOD__
 591                 );
 592                 return (int)$this->mUnpatrolled;
 593         }
 594
 595         /**
 596          * @param $field int one of DELETED_* bitfield constants
 597          *
 598          * @return Boolean
 599          */
 600         public function isDeleted( $field ) {
 601                 return ( $this->mDeleted & $field ) == $field;
 602         }
 603
 604         /**
 605          * Get the deletion bitfield of the revision
 606          *
 607          * @return int
 608          */
 609         public function getVisibility() {
 610                 return (int)$this->mDeleted;
 611         }
 612
 613         /**
 614          * Fetch revision text if it's available to the specified audience.
 615          * If the specified audience does not have the ability to view this
 616          * revision, an empty string will be returned.
 617          *
 618          * @param $audience Integer: one of:
 619          *      Revision::FOR_PUBLIC       to be displayed to all users
 620          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 621          *      Revision::RAW              get the text regardless of permissions
 622          *
 623          * @return String
 624          */
 625         public function getText( $audience = self::FOR_PUBLIC ) {
 626                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 627                         return '';
 628                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT ) ) {
 629                         return '';
 630                 } else {
 631                         return $this->getRawText();
 632                 }
 633         }
 634
 635         /**
 636          * Alias for getText(Revision::FOR_THIS_USER)
 637          *
 638          * @deprecated since 1.17
 639          * @return String
 640          */
 641         public function revText() {
 642                 wfDeprecated( __METHOD__ );
 643                 return $this->getText( self::FOR_THIS_USER );
 644         }
 645
 646         /**
 647          * Fetch revision text without regard for view restrictions
 648          *
 649          * @return String
 650          */
 651         public function getRawText() {
 652                 if( is_null( $this->mText ) ) {
 653                         // Revision text is immutable. Load on demand:
 654                         $this->mText = $this->loadText();
 655                 }
 656                 return $this->mText;
 657         }
 658
 659         /**
 660          * @return String
 661          */
 662         public function getTimestamp() {
 663                 return wfTimestamp( TS_MW, $this->mTimestamp );
 664         }
 665
 666         /**
 667          * @return Boolean
 668          */
 669         public function isCurrent() {
 670                 return $this->mCurrent;
 671         }
 672
 673         /**
 674          * Get previous revision for this title
 675          *
 676          * @return Revision or null
 677          */
 678         public function getPrevious() {
 679                 if( $this->getTitle() ) {
 680                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 681                         if( $prev ) {
 682                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 683                         }
 684                 }
 685                 return null;
 686         }
 687
 688         /**
 689          * Get next revision for this title
 690          *
 691          * @return Revision or null
 692          */
 693         public function getNext() {
 694                 if( $this->getTitle() ) {
 695                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 696                         if ( $next ) {
 697                                 return Revision::newFromTitle( $this->getTitle(), $next );
 698                         }
 699                 }
 700                 return null;
 701         }
 702
 703         /**
 704          * Get previous revision Id for this page_id
 705          * This is used to populate rev_parent_id on save
 706          *
 707          * @param $db DatabaseBase
 708          * @return Integer
 709          */
 710         private function getPreviousRevisionId( $db ) {
 711                 if( is_null( $this->mPage ) ) {
 712                         return 0;
 713                 }
 714                 # Use page_latest if ID is not given
 715                 if( !$this->mId ) {
 716                         $prevId = $db->selectField( 'page', 'page_latest',
 717                                 array( 'page_id' => $this->mPage ),
 718                                 __METHOD__ );
 719                 } else {
 720                         $prevId = $db->selectField( 'revision', 'rev_id',
 721                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 722                                 __METHOD__,
 723                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 724                 }
 725                 return intval( $prevId );
 726         }
 727
 728         /**
 729           * Get revision text associated with an old or archive row
 730           * $row is usually an object from wfFetchRow(), both the flags and the text
 731           * field must be included
 732           *
 733           * @param $row Object: the text data
 734           * @param $prefix String: table prefix (default 'old_')
 735           * @return String: text the text requested or false on failure
 736           */
 737         public static function getRevisionText( $row, $prefix = 'old_' ) {
 738                 wfProfileIn( __METHOD__ );
 739
 740                 # Get data
 741                 $textField = $prefix . 'text';
 742                 $flagsField = $prefix . 'flags';
 743
 744                 if( isset( $row->$flagsField ) ) {
 745                         $flags = explode( ',', $row->$flagsField );
 746                 } else {
 747                         $flags = array();
 748                 }
 749
 750                 if( isset( $row->$textField ) ) {
 751                         $text = $row->$textField;
 752                 } else {
 753                         wfProfileOut( __METHOD__ );
 754                         return false;
 755                 }
 756
 757                 # Use external methods for external objects, text in table is URL-only then
 758                 if ( in_array( 'external', $flags ) ) {
 759                         $url = $text;
 760                         $parts = explode( '://', $url, 2 );
 761                         if( count( $parts ) == 1 || $parts[1] == '' ) {
 762                                 wfProfileOut( __METHOD__ );
 763                                 return false;
 764                         }
 765                         $text = ExternalStore::fetchFromURL( $url );
 766                 }
 767
 768                 // If the text was fetched without an error, convert it
 769                 if ( $text !== false ) {
 770                         if( in_array( 'gzip', $flags ) ) {
 771                                 # Deal with optional compression of archived pages.
 772                                 # This can be done periodically via maintenance/compressOld.php, and
 773                                 # as pages are saved if $wgCompressRevisions is set.
 774                                 $text = gzinflate( $text );
 775                         }
 776
 777                         if( in_array( 'object', $flags ) ) {
 778                                 # Generic compressed storage
 779                                 $obj = unserialize( $text );
 780                                 if ( !is_object( $obj ) ) {
 781                                         // Invalid object
 782                                         wfProfileOut( __METHOD__ );
 783                                         return false;
 784                                 }
 785                                 $text = $obj->getText();
 786                         }
 787
 788                         global $wgLegacyEncoding;
 789                         if( $text !== false && $wgLegacyEncoding
 790                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
 791                         {
 792                                 # Old revisions kept around in a legacy encoding?
 793                                 # Upconvert on demand.
 794                                 # ("utf8" checked for compatibility with some broken
 795                                 #  conversion scripts 2008-12-30)
 796                                 global $wgContLang;
 797                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
 798                         }
 799                 }
 800                 wfProfileOut( __METHOD__ );
 801                 return $text;
 802         }
 803
 804         /**
 805          * If $wgCompressRevisions is enabled, we will compress data.
 806          * The input string is modified in place.
 807          * Return value is the flags field: contains 'gzip' if the
 808          * data is compressed, and 'utf-8' if we're saving in UTF-8
 809          * mode.
 810          *
 811          * @param $text Mixed: reference to a text
 812          * @return String
 813          */
 814         public static function compressRevisionText( &$text ) {
 815                 global $wgCompressRevisions;
 816                 $flags = array();
 817
 818                 # Revisions not marked this way will be converted
 819                 # on load if $wgLegacyCharset is set in the future.
 820                 $flags[] = 'utf-8';
 821
 822                 if( $wgCompressRevisions ) {
 823                         if( function_exists( 'gzdeflate' ) ) {
 824                                 $text = gzdeflate( $text );
 825                                 $flags[] = 'gzip';
 826                         } else {
 827                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 828                         }
 829                 }
 830                 return implode( ',', $flags );
 831         }
 832
 833         /**
 834          * Insert a new revision into the database, returning the new revision ID
 835          * number on success and dies horribly on failure.
 836          *
 837          * @param $dbw DatabaseBase: (master connection)
 838          * @return Integer
 839          */
 840         public function insertOn( $dbw ) {
 841                 global $wgDefaultExternalStore;
 842
 843                 wfProfileIn( __METHOD__ );
 844
 845                 $data = $this->mText;
 846                 $flags = Revision::compressRevisionText( $data );
 847
 848                 # Write to external storage if required
 849                 if( $wgDefaultExternalStore ) {
 850                         // Store and get the URL
 851                         $data = ExternalStore::insertToDefault( $data );
 852                         if( !$data ) {
 853                                 throw new MWException( "Unable to store text to external storage" );
 854                         }
 855                         if( $flags ) {
 856                                 $flags .= ',';
 857                         }
 858                         $flags .= 'external';
 859                 }
 860
 861                 # Record the text (or external storage URL) to the text table
 862                 if( !isset( $this->mTextId ) ) {
 863                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
 864                         $dbw->insert( 'text',
 865                                 array(
 866                                         'old_id'    => $old_id,
 867                                         'old_text'  => $data,
 868                                         'old_flags' => $flags,
 869                                 ), __METHOD__
 870                         );
 871                         $this->mTextId = $dbw->insertId();
 872                 }
 873
 874                 if ( $this->mComment === null ) $this->mComment = "";
 875
 876                 # Record the edit in revisions
 877                 $rev_id = isset( $this->mId )
 878                         ? $this->mId
 879                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
 880                 $dbw->insert( 'revision',
 881                         array(
 882                                 'rev_id'         => $rev_id,
 883                                 'rev_page'       => $this->mPage,
 884                                 'rev_text_id'    => $this->mTextId,
 885                                 'rev_comment'    => $this->mComment,
 886                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 887                                 'rev_user'       => $this->mUser,
 888                                 'rev_user_text'  => $this->mUserText,
 889                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 890                                 'rev_deleted'    => $this->mDeleted,
 891                                 'rev_len'        => $this->mSize,
 892                                 'rev_parent_id'  => is_null($this->mParentId) ?
 893                                         $this->getPreviousRevisionId( $dbw ) : $this->mParentId
 894                         ), __METHOD__
 895                 );
 896
 897                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
 898
 899                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 900
 901                 wfProfileOut( __METHOD__ );
 902                 return $this->mId;
 903         }
 904
 905         /**
 906          * Lazy-load the revision's text.
 907          * Currently hardcoded to the 'text' table storage engine.
 908          *
 909          * @return String
 910          */
 911         protected function loadText() {
 912                 wfProfileIn( __METHOD__ );
 913
 914                 // Caching may be beneficial for massive use of external storage
 915                 global $wgRevisionCacheExpiry, $wgMemc;
 916                 $textId = $this->getTextId();
 917                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
 918                 if( $wgRevisionCacheExpiry ) {
 919                         $text = $wgMemc->get( $key );
 920                         if( is_string( $text ) ) {
 921                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
 922                                 wfProfileOut( __METHOD__ );
 923                                 return $text;
 924                         }
 925                 }
 926
 927                 // If we kept data for lazy extraction, use it now...
 928                 if ( isset( $this->mTextRow ) ) {
 929                         $row = $this->mTextRow;
 930                         $this->mTextRow = null;
 931                 } else {
 932                         $row = null;
 933                 }
 934
 935                 if( !$row ) {
 936                         // Text data is immutable; check slaves first.
 937                         $dbr = wfGetDB( DB_SLAVE );
 938                         $row = $dbr->selectRow( 'text',
 939                                 array( 'old_text', 'old_flags' ),
 940                                 array( 'old_id' => $this->getTextId() ),
 941                                 __METHOD__ );
 942                 }
 943
 944                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
 945                         // Possible slave lag!
 946                         $dbw = wfGetDB( DB_MASTER );
 947                         $row = $dbw->selectRow( 'text',
 948                                 array( 'old_text', 'old_flags' ),
 949                                 array( 'old_id' => $this->getTextId() ),
 950                                 __METHOD__ );
 951                 }
 952
 953                 $text = self::getRevisionText( $row );
 954
 955                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
 956                 if( $wgRevisionCacheExpiry && $text !== false ) {
 957                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 958                 }
 959
 960                 wfProfileOut( __METHOD__ );
 961
 962                 return $text;
 963         }
 964
 965         /**
 966          * Create a new null-revision for insertion into a page's
 967          * history. This will not re-save the text, but simply refer
 968          * to the text from the previous version.
 969          *
 970          * Such revisions can for instance identify page rename
 971          * operations and other such meta-modifications.
 972          *
 973          * @param $dbw DatabaseBase
 974          * @param $pageId Integer: ID number of the page to read from
 975          * @param $summary String: revision's summary
 976          * @param $minor Boolean: whether the revision should be considered as minor
 977          * @return Revision|null on error
 978          */
 979         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
 980                 wfProfileIn( __METHOD__ );
 981
 982                 $current = $dbw->selectRow(
 983                         array( 'page', 'revision' ),
 984                         array( 'page_latest', 'rev_text_id', 'rev_len' ),
 985                         array(
 986                                 'page_id' => $pageId,
 987                                 'page_latest=rev_id',
 988                                 ),
 989                         __METHOD__ );
 990
 991                 if( $current ) {
 992                         $revision = new Revision( array(
 993                                 'page'       => $pageId,
 994                                 'comment'    => $summary,
 995                                 'minor_edit' => $minor,
 996                                 'text_id'    => $current->rev_text_id,
 997                                 'parent_id'  => $current->page_latest,
 998                                 'len'        => $current->rev_len
 999                                 ) );
1000                 } else {
1001                         $revision = null;
1002                 }
1003
1004                 wfProfileOut( __METHOD__ );
1005                 return $revision;
1006         }
1007
1008         /**
1009          * Determine if the current user is allowed to view a particular
1010          * field of this revision, if it's marked as deleted.
1011          *
1012          * @param $field Integer:one of self::DELETED_TEXT,
1013          *                              self::DELETED_COMMENT,
1014          *                              self::DELETED_USER
1015          * @return Boolean
1016          */
1017         public function userCan( $field ) {
1018                 return self::userCanBitfield( $this->mDeleted, $field );
1019         }
1020
1021         /**
1022          * Determine if the current user is allowed to view a particular
1023          * field of this revision, if it's marked as deleted. This is used
1024          * by various classes to avoid duplication.
1025          *
1026          * @param $bitfield Integer: current field
1027          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1028          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1029          *                               self::DELETED_USER = File::DELETED_USER
1030          * @return Boolean
1031          */
1032         public static function userCanBitfield( $bitfield, $field ) {
1033                 if( $bitfield & $field ) { // aspect is deleted
1034                         global $wgUser;
1035                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1036                                 $permission = 'suppressrevision';
1037                         } elseif ( $field & self::DELETED_TEXT ) {
1038                                 $permission = 'deletedtext';
1039                         } else {
1040                                 $permission = 'deletedhistory';
1041                         }
1042                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1043                         return $wgUser->isAllowed( $permission );
1044                 } else {
1045                         return true;
1046                 }
1047         }
1048
1049         /**
1050          * Get rev_timestamp from rev_id, without loading the rest of the row
1051          *
1052          * @param $title Title
1053          * @param $id Integer
1054          * @return String
1055          */
1056         static function getTimestampFromId( $title, $id ) {
1057                 $dbr = wfGetDB( DB_SLAVE );
1058                 // Casting fix for DB2
1059                 if ( $id == '' ) {
1060                         $id = 0;
1061                 }
1062                 $conds = array( 'rev_id' => $id );
1063                 $conds['rev_page'] = $title->getArticleId();
1064                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1065                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1066                         # Not in slave, try master
1067                         $dbw = wfGetDB( DB_MASTER );
1068                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1069                 }
1070                 return wfTimestamp( TS_MW, $timestamp );
1071         }
1072
1073         /**
1074          * Get count of revisions per page...not very efficient
1075          *
1076          * @param $db DatabaseBase
1077          * @param $id Integer: page id
1078          * @return Integer
1079          */
1080         static function countByPageId( $db, $id ) {
1081                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1082                         array( 'rev_page' => $id ), __METHOD__ );
1083                 if( $row ) {
1084                         return $row->revCount;
1085                 }
1086                 return 0;
1087         }
1088
1089         /**
1090          * Get count of revisions per page...not very efficient
1091          *
1092          * @param $db DatabaseBase
1093          * @param $title Title
1094          * @return Integer
1095          */
1096         static function countByTitle( $db, $title ) {
1097                 $id = $title->getArticleId();
1098                 if( $id ) {
1099                         return Revision::countByPageId( $db, $id );
1100                 }
1101                 return 0;
1102         }
1103 }