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                         'sha1'       => $row->ar_sha1
 115                 );
 116                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 117                         // Pre-1.5 ar_text row
 118                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 119                         if ( $attribs['text'] === false ) {
 120                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 121                         }
 122                 }
 123                 return new self( $attribs );
 124         }
 125
 126         /**
 127          * @since 1.19
 128          *
 129          * @param $row
 130          * @return Revision
 131          */
 132         public static function newFromRow( $row ) {
 133                 return new self( $row );
 134         }
 135
 136         /**
 137          * Load a page revision from a given revision ID number.
 138          * Returns null if no such revision can be found.
 139          *
 140          * @param $db DatabaseBase
 141          * @param $id Integer
 142          * @return Revision or null
 143          */
 144         public static function loadFromId( $db, $id ) {
 145                 return Revision::loadFromConds( $db,
 146                         array( 'page_id=rev_page',
 147                                    'rev_id' => intval( $id ) ) );
 148         }
 149
 150         /**
 151          * Load either the current, or a specified, revision
 152          * that's attached to a given page. If not attached
 153          * to that page, will return null.
 154          *
 155          * @param $db DatabaseBase
 156          * @param $pageid Integer
 157          * @param $id Integer
 158          * @return Revision or null
 159          */
 160         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 161                 $conds = array( 'page_id=rev_page','rev_page' => intval( $pageid ), 'page_id'=>intval( $pageid ) );
 162                 if( $id ) {
 163                         $conds['rev_id'] = intval( $id );
 164                 } else {
 165                         $conds[] = 'rev_id=page_latest';
 166                 }
 167                 return Revision::loadFromConds( $db, $conds );
 168         }
 169
 170         /**
 171          * Load either the current, or a specified, revision
 172          * that's attached to a given page. If not attached
 173          * to that page, will return null.
 174          *
 175          * @param $db DatabaseBase
 176          * @param $title Title
 177          * @param $id Integer
 178          * @return Revision or null
 179          */
 180         public static function loadFromTitle( $db, $title, $id = 0 ) {
 181                 if( $id ) {
 182                         $matchId = intval( $id );
 183                 } else {
 184                         $matchId = 'page_latest';
 185                 }
 186                 return Revision::loadFromConds(
 187                         $db,
 188                         array( "rev_id=$matchId",
 189                                    'page_id=rev_page',
 190                                    'page_namespace' => $title->getNamespace(),
 191                                    'page_title'     => $title->getDBkey() ) );
 192         }
 193
 194         /**
 195          * Load the revision for the given title with the given timestamp.
 196          * WARNING: Timestamps may in some circumstances not be unique,
 197          * so this isn't the best key to use.
 198          *
 199          * @param $db DatabaseBase
 200          * @param $title Title
 201          * @param $timestamp String
 202          * @return Revision or null
 203          */
 204         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 205                 return Revision::loadFromConds(
 206                         $db,
 207                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 208                                    'page_id=rev_page',
 209                                    'page_namespace' => $title->getNamespace(),
 210                                    'page_title'     => $title->getDBkey() ) );
 211         }
 212
 213         /**
 214          * Given a set of conditions, fetch a revision.
 215          *
 216          * @param $conditions Array
 217          * @return Revision or null
 218          */
 219         public static function newFromConds( $conditions ) {
 220                 $db = wfGetDB( DB_SLAVE );
 221                 $row = Revision::loadFromConds( $db, $conditions );
 222                 if( is_null( $row ) && wfGetLB()->getServerCount() > 1 ) {
 223                         $dbw = wfGetDB( DB_MASTER );
 224                         $row = Revision::loadFromConds( $dbw, $conditions );
 225                 }
 226                 return $row;
 227         }
 228
 229         /**
 230          * Given a set of conditions, fetch a revision from
 231          * the given database connection.
 232          *
 233          * @param $db DatabaseBase
 234          * @param $conditions Array
 235          * @return Revision or null
 236          */
 237         private static function loadFromConds( $db, $conditions ) {
 238                 $res = Revision::fetchFromConds( $db, $conditions );
 239                 if( $res ) {
 240                         $row = $res->fetchObject();
 241                         $res->free();
 242                         if( $row ) {
 243                                 $ret = new Revision( $row );
 244                                 return $ret;
 245                         }
 246                 }
 247                 $ret = null;
 248                 return $ret;
 249         }
 250
 251         /**
 252          * Return a wrapper for a series of database rows to
 253          * fetch all of a given page's revisions in turn.
 254          * Each row can be fed to the constructor to get objects.
 255          *
 256          * @param $title Title
 257          * @return ResultWrapper
 258          */
 259         public static function fetchRevision( $title ) {
 260                 return Revision::fetchFromConds(
 261                         wfGetDB( DB_SLAVE ),
 262                         array( 'rev_id=page_latest',
 263                                    'page_namespace' => $title->getNamespace(),
 264                                    'page_title'     => $title->getDBkey(),
 265                                    'page_id=rev_page' ) );
 266         }
 267
 268         /**
 269          * Given a set of conditions, return a ResultWrapper
 270          * which will return matching database rows with the
 271          * fields necessary to build Revision objects.
 272          *
 273          * @param $db DatabaseBase
 274          * @param $conditions Array
 275          * @return ResultWrapper
 276          */
 277         private static function fetchFromConds( $db, $conditions ) {
 278                 $fields = self::selectFields();
 279                 $fields[] = 'page_namespace';
 280                 $fields[] = 'page_title';
 281                 $fields[] = 'page_latest';
 282                 return $db->select(
 283                         array( 'page', 'revision' ),
 284                         $fields,
 285                         $conditions,
 286                         __METHOD__,
 287                         array( 'LIMIT' => 1 ) );
 288         }
 289
 290         /**
 291          * Return the list of revision fields that should be selected to create
 292          * a new revision.
 293          */
 294         public static function selectFields() {
 295                 return array(
 296                         'rev_id',
 297                         'rev_page',
 298                         'rev_text_id',
 299                         'rev_timestamp',
 300                         'rev_comment',
 301                         'rev_user_text,'.
 302                         'rev_user',
 303                         'rev_minor_edit',
 304                         'rev_deleted',
 305                         'rev_len',
 306                         'rev_parent_id',
 307                         'rev_sha1'
 308                 );
 309         }
 310
 311         /**
 312          * Return the list of text fields that should be selected to read the
 313          * revision text
 314          */
 315         static function selectTextFields() {
 316                 return array(
 317                         'old_text',
 318                         'old_flags'
 319                 );
 320         }
 321
 322         /**
 323          * Return the list of page fields that should be selected from page table
 324          */
 325         static function selectPageFields() {
 326                 return array(
 327                         'page_namespace',
 328                         'page_title',
 329                         'page_latest'
 330                 );
 331         }
 332
 333         /**
 334          * Constructor
 335          *
 336          * @param $row Mixed: either a database row or an array
 337          * @access private
 338          */
 339         function __construct( $row ) {
 340                 if( is_object( $row ) ) {
 341                         $this->mId        = intval( $row->rev_id );
 342                         $this->mPage      = intval( $row->rev_page );
 343                         $this->mTextId    = intval( $row->rev_text_id );
 344                         $this->mComment   =         $row->rev_comment;
 345                         $this->mUserText  =         $row->rev_user_text;
 346                         $this->mUser      = intval( $row->rev_user );
 347                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 348                         $this->mTimestamp =         $row->rev_timestamp;
 349                         $this->mDeleted   = intval( $row->rev_deleted );
 350
 351                         if( !isset( $row->rev_parent_id ) ) {
 352                                 $this->mParentId = is_null($row->rev_parent_id) ? null : 0;
 353                         } else {
 354                                 $this->mParentId  = intval( $row->rev_parent_id );
 355                         }
 356
 357                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) ) {
 358                                 $this->mSize = null;
 359                         } else {
 360                                 $this->mSize = intval( $row->rev_len );
 361                         }
 362
 363                         if ( !isset( $row->rev_sha1 ) ) {
 364                                 $this->mSha1 = null;
 365                         } else {
 366                                 $this->mSha1 = $row->rev_sha1;
 367                         }
 368
 369                         if( isset( $row->page_latest ) ) {
 370                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 371                                 $this->mTitle = Title::newFromRow( $row );
 372                         } else {
 373                                 $this->mCurrent = false;
 374                                 $this->mTitle = null;
 375                         }
 376
 377                         // Lazy extraction...
 378                         $this->mText      = null;
 379                         if( isset( $row->old_text ) ) {
 380                                 $this->mTextRow = $row;
 381                         } else {
 382                                 // 'text' table row entry will be lazy-loaded
 383                                 $this->mTextRow = null;
 384                         }
 385                 } elseif( is_array( $row ) ) {
 386                         // Build a new revision to be saved...
 387                         global $wgUser; // ugh
 388
 389                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 390                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 391                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 392                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 393                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 394                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 395                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 396                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 397                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 398                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 399                         $this->mSha1      = isset( $row['sha1']  )      ? strval( $row['sha1']  )      : null;
 400
 401                         // Enforce spacing trimming on supplied text
 402                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 403                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 404                         $this->mTextRow   = null;
 405
 406                         $this->mTitle     = null; # Load on demand if needed
 407                         $this->mCurrent   = false;
 408                         # If we still have no length, see it we have the text to figure it out
 409                         if ( !$this->mSize ) {
 410                                 $this->mSize = is_null( $this->mText ) ? null : strlen( $this->mText );
 411                         }
 412                         # Same for sha1
 413                         if ( $this->mSha1 === null ) {
 414                                 $this->mSha1 = is_null( $this->mText ) ? null : self::base36Sha1( $this->mText );
 415                         }
 416                 } else {
 417                         throw new MWException( 'Revision constructor passed invalid row format.' );
 418                 }
 419                 $this->mUnpatrolled = null;
 420         }
 421
 422         /**
 423          * Get revision ID
 424          *
 425          * @return Integer
 426          */
 427         public function getId() {
 428                 return $this->mId;
 429         }
 430
 431         /**
 432          * Get text row ID
 433          *
 434          * @return Integer
 435          */
 436         public function getTextId() {
 437                 return $this->mTextId;
 438         }
 439
 440         /**
 441          * Get parent revision ID (the original previous page revision)
 442          *
 443          * @return Integer
 444          */
 445         public function getParentId() {
 446                 return $this->mParentId;
 447         }
 448
 449         /**
 450          * Returns the length of the text in this revision, or null if unknown.
 451          *
 452          * @return Integer
 453          */
 454         public function getSize() {
 455                 return $this->mSize;
 456         }
 457
 458         /**
 459          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 460          *
 461          * @return String
 462          */
 463         public function getSha1() {
 464                 return $this->mSha1;
 465         }
 466
 467         /**
 468          * Returns the title of the page associated with this entry.
 469          *
 470          * @return Title
 471          */
 472         public function getTitle() {
 473                 if( isset( $this->mTitle ) ) {
 474                         return $this->mTitle;
 475                 }
 476                 $dbr = wfGetDB( DB_SLAVE );
 477                 $row = $dbr->selectRow(
 478                         array( 'page', 'revision' ),
 479                         array( 'page_namespace', 'page_title' ),
 480                         array( 'page_id=rev_page',
 481                                    'rev_id' => $this->mId ),
 482                         'Revision::getTitle' );
 483                 if( $row ) {
 484                         $this->mTitle = Title::makeTitle( $row->page_namespace, $row->page_title );
 485                 }
 486                 return $this->mTitle;
 487         }
 488
 489         /**
 490          * Set the title of the revision
 491          *
 492          * @param $title Title
 493          */
 494         public function setTitle( $title ) {
 495                 $this->mTitle = $title;
 496         }
 497
 498         /**
 499          * Get the page ID
 500          *
 501          * @return Integer
 502          */
 503         public function getPage() {
 504                 return $this->mPage;
 505         }
 506
 507         /**
 508          * Fetch revision's user id if it's available to the specified audience.
 509          * If the specified audience does not have access to it, zero will be
 510          * returned.
 511          *
 512          * @param $audience Integer: one of:
 513          *      Revision::FOR_PUBLIC       to be displayed to all users
 514          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 515          *      Revision::RAW              get the ID regardless of permissions
 516          *
 517          *
 518          * @return Integer
 519          */
 520         public function getUser( $audience = self::FOR_PUBLIC ) {
 521                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 522                         return 0;
 523                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 524                         return 0;
 525                 } else {
 526                         return $this->mUser;
 527                 }
 528         }
 529
 530         /**
 531          * Fetch revision's user id without regard for the current user's permissions
 532          *
 533          * @return String
 534          */
 535         public function getRawUser() {
 536                 return $this->mUser;
 537         }
 538
 539         /**
 540          * Fetch revision's username if it's available to the specified audience.
 541          * If the specified audience does not have access to the username, an
 542          * empty string will be returned.
 543          *
 544          * @param $audience Integer: one of:
 545          *      Revision::FOR_PUBLIC       to be displayed to all users
 546          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 547          *      Revision::RAW              get the text regardless of permissions
 548          *
 549          * @return string
 550          */
 551         public function getUserText( $audience = self::FOR_PUBLIC ) {
 552                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 553                         return '';
 554                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 555                         return '';
 556                 } else {
 557                         return $this->mUserText;
 558                 }
 559         }
 560
 561         /**
 562          * Fetch revision's username without regard for view restrictions
 563          *
 564          * @return String
 565          */
 566         public function getRawUserText() {
 567                 return $this->mUserText;
 568         }
 569
 570         /**
 571          * Fetch revision comment if it's available to the specified audience.
 572          * If the specified audience does not have access to the comment, an
 573          * empty string will be returned.
 574          *
 575          * @param $audience Integer: one of:
 576          *      Revision::FOR_PUBLIC       to be displayed to all users
 577          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 578          *      Revision::RAW              get the text regardless of permissions
 579          *
 580          * @return String
 581          */
 582         function getComment( $audience = self::FOR_PUBLIC ) {
 583                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 584                         return '';
 585                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT ) ) {
 586                         return '';
 587                 } else {
 588                         return $this->mComment;
 589                 }
 590         }
 591
 592         /**
 593          * Fetch revision comment without regard for the current user's permissions
 594          *
 595          * @return String
 596          */
 597         public function getRawComment() {
 598                 return $this->mComment;
 599         }
 600
 601         /**
 602          * @return Boolean
 603          */
 604         public function isMinor() {
 605                 return (bool)$this->mMinorEdit;
 606         }
 607
 608         /**
 609          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 610          */
 611         public function isUnpatrolled() {
 612                 if( $this->mUnpatrolled !== null ) {
 613                         return $this->mUnpatrolled;
 614                 }
 615                 $dbr = wfGetDB( DB_SLAVE );
 616                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 617                         'rc_id',
 618                         array( // Add redundant user,timestamp condition so we can use the existing index
 619                                 'rc_user_text'  => $this->getRawUserText(),
 620                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 621                                 'rc_this_oldid' => $this->getId(),
 622                                 'rc_patrolled'  => 0
 623                         ),
 624                         __METHOD__
 625                 );
 626                 return (int)$this->mUnpatrolled;
 627         }
 628
 629         /**
 630          * @param $field int one of DELETED_* bitfield constants
 631          *
 632          * @return Boolean
 633          */
 634         public function isDeleted( $field ) {
 635                 return ( $this->mDeleted & $field ) == $field;
 636         }
 637
 638         /**
 639          * Get the deletion bitfield of the revision
 640          *
 641          * @return int
 642          */
 643         public function getVisibility() {
 644                 return (int)$this->mDeleted;
 645         }
 646
 647         /**
 648          * Fetch revision text if it's available to the specified audience.
 649          * If the specified audience does not have the ability to view this
 650          * revision, an empty string will be returned.
 651          *
 652          * @param $audience Integer: one of:
 653          *      Revision::FOR_PUBLIC       to be displayed to all users
 654          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 655          *      Revision::RAW              get the text regardless of permissions
 656          *
 657          * @return String
 658          */
 659         public function getText( $audience = self::FOR_PUBLIC ) {
 660                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 661                         return '';
 662                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT ) ) {
 663                         return '';
 664                 } else {
 665                         return $this->getRawText();
 666                 }
 667         }
 668
 669         /**
 670          * Alias for getText(Revision::FOR_THIS_USER)
 671          *
 672          * @deprecated since 1.17
 673          * @return String
 674          */
 675         public function revText() {
 676                 wfDeprecated( __METHOD__ );
 677                 return $this->getText( self::FOR_THIS_USER );
 678         }
 679
 680         /**
 681          * Fetch revision text without regard for view restrictions
 682          *
 683          * @return String
 684          */
 685         public function getRawText() {
 686                 if( is_null( $this->mText ) ) {
 687                         // Revision text is immutable. Load on demand:
 688                         $this->mText = $this->loadText();
 689                 }
 690                 return $this->mText;
 691         }
 692
 693         /**
 694          * @return String
 695          */
 696         public function getTimestamp() {
 697                 return wfTimestamp( TS_MW, $this->mTimestamp );
 698         }
 699
 700         /**
 701          * @return Boolean
 702          */
 703         public function isCurrent() {
 704                 return $this->mCurrent;
 705         }
 706
 707         /**
 708          * Get previous revision for this title
 709          *
 710          * @return Revision or null
 711          */
 712         public function getPrevious() {
 713                 if( $this->getTitle() ) {
 714                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 715                         if( $prev ) {
 716                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 717                         }
 718                 }
 719                 return null;
 720         }
 721
 722         /**
 723          * Get next revision for this title
 724          *
 725          * @return Revision or null
 726          */
 727         public function getNext() {
 728                 if( $this->getTitle() ) {
 729                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 730                         if ( $next ) {
 731                                 return Revision::newFromTitle( $this->getTitle(), $next );
 732                         }
 733                 }
 734                 return null;
 735         }
 736
 737         /**
 738          * Get previous revision Id for this page_id
 739          * This is used to populate rev_parent_id on save
 740          *
 741          * @param $db DatabaseBase
 742          * @return Integer
 743          */
 744         private function getPreviousRevisionId( $db ) {
 745                 if( is_null( $this->mPage ) ) {
 746                         return 0;
 747                 }
 748                 # Use page_latest if ID is not given
 749                 if( !$this->mId ) {
 750                         $prevId = $db->selectField( 'page', 'page_latest',
 751                                 array( 'page_id' => $this->mPage ),
 752                                 __METHOD__ );
 753                 } else {
 754                         $prevId = $db->selectField( 'revision', 'rev_id',
 755                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 756                                 __METHOD__,
 757                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 758                 }
 759                 return intval( $prevId );
 760         }
 761
 762         /**
 763           * Get revision text associated with an old or archive row
 764           * $row is usually an object from wfFetchRow(), both the flags and the text
 765           * field must be included
 766           *
 767           * @param $row Object: the text data
 768           * @param $prefix String: table prefix (default 'old_')
 769           * @return String: text the text requested or false on failure
 770           */
 771         public static function getRevisionText( $row, $prefix = 'old_' ) {
 772                 wfProfileIn( __METHOD__ );
 773
 774                 # Get data
 775                 $textField = $prefix . 'text';
 776                 $flagsField = $prefix . 'flags';
 777
 778                 if( isset( $row->$flagsField ) ) {
 779                         $flags = explode( ',', $row->$flagsField );
 780                 } else {
 781                         $flags = array();
 782                 }
 783
 784                 if( isset( $row->$textField ) ) {
 785                         $text = $row->$textField;
 786                 } else {
 787                         wfProfileOut( __METHOD__ );
 788                         return false;
 789                 }
 790
 791                 # Use external methods for external objects, text in table is URL-only then
 792                 if ( in_array( 'external', $flags ) ) {
 793                         $url = $text;
 794                         $parts = explode( '://', $url, 2 );
 795                         if( count( $parts ) == 1 || $parts[1] == '' ) {
 796                                 wfProfileOut( __METHOD__ );
 797                                 return false;
 798                         }
 799                         $text = ExternalStore::fetchFromURL( $url );
 800                 }
 801
 802                 // If the text was fetched without an error, convert it
 803                 if ( $text !== false ) {
 804                         if( in_array( 'gzip', $flags ) ) {
 805                                 # Deal with optional compression of archived pages.
 806                                 # This can be done periodically via maintenance/compressOld.php, and
 807                                 # as pages are saved if $wgCompressRevisions is set.
 808                                 $text = gzinflate( $text );
 809                         }
 810
 811                         if( in_array( 'object', $flags ) ) {
 812                                 # Generic compressed storage
 813                                 $obj = unserialize( $text );
 814                                 if ( !is_object( $obj ) ) {
 815                                         // Invalid object
 816                                         wfProfileOut( __METHOD__ );
 817                                         return false;
 818                                 }
 819                                 $text = $obj->getText();
 820                         }
 821
 822                         global $wgLegacyEncoding;
 823                         if( $text !== false && $wgLegacyEncoding
 824                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
 825                         {
 826                                 # Old revisions kept around in a legacy encoding?
 827                                 # Upconvert on demand.
 828                                 # ("utf8" checked for compatibility with some broken
 829                                 #  conversion scripts 2008-12-30)
 830                                 global $wgContLang;
 831                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
 832                         }
 833                 }
 834                 wfProfileOut( __METHOD__ );
 835                 return $text;
 836         }
 837
 838         /**
 839          * If $wgCompressRevisions is enabled, we will compress data.
 840          * The input string is modified in place.
 841          * Return value is the flags field: contains 'gzip' if the
 842          * data is compressed, and 'utf-8' if we're saving in UTF-8
 843          * mode.
 844          *
 845          * @param $text Mixed: reference to a text
 846          * @return String
 847          */
 848         public static function compressRevisionText( &$text ) {
 849                 global $wgCompressRevisions;
 850                 $flags = array();
 851
 852                 # Revisions not marked this way will be converted
 853                 # on load if $wgLegacyCharset is set in the future.
 854                 $flags[] = 'utf-8';
 855
 856                 if( $wgCompressRevisions ) {
 857                         if( function_exists( 'gzdeflate' ) ) {
 858                                 $text = gzdeflate( $text );
 859                                 $flags[] = 'gzip';
 860                         } else {
 861                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 862                         }
 863                 }
 864                 return implode( ',', $flags );
 865         }
 866
 867         /**
 868          * Insert a new revision into the database, returning the new revision ID
 869          * number on success and dies horribly on failure.
 870          *
 871          * @param $dbw DatabaseBase: (master connection)
 872          * @return Integer
 873          */
 874         public function insertOn( $dbw ) {
 875                 global $wgDefaultExternalStore;
 876
 877                 wfProfileIn( __METHOD__ );
 878
 879                 $data = $this->mText;
 880                 $flags = Revision::compressRevisionText( $data );
 881
 882                 # Write to external storage if required
 883                 if( $wgDefaultExternalStore ) {
 884                         // Store and get the URL
 885                         $data = ExternalStore::insertToDefault( $data );
 886                         if( !$data ) {
 887                                 throw new MWException( "Unable to store text to external storage" );
 888                         }
 889                         if( $flags ) {
 890                                 $flags .= ',';
 891                         }
 892                         $flags .= 'external';
 893                 }
 894
 895                 # Record the text (or external storage URL) to the text table
 896                 if( !isset( $this->mTextId ) ) {
 897                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
 898                         $dbw->insert( 'text',
 899                                 array(
 900                                         'old_id'    => $old_id,
 901                                         'old_text'  => $data,
 902                                         'old_flags' => $flags,
 903                                 ), __METHOD__
 904                         );
 905                         $this->mTextId = $dbw->insertId();
 906                 }
 907
 908                 if ( $this->mComment === null ) $this->mComment = "";
 909
 910                 # Record the edit in revisions
 911                 $rev_id = isset( $this->mId )
 912                         ? $this->mId
 913                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
 914                 $dbw->insert( 'revision',
 915                         array(
 916                                 'rev_id'         => $rev_id,
 917                                 'rev_page'       => $this->mPage,
 918                                 'rev_text_id'    => $this->mTextId,
 919                                 'rev_comment'    => $this->mComment,
 920                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 921                                 'rev_user'       => $this->mUser,
 922                                 'rev_user_text'  => $this->mUserText,
 923                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 924                                 'rev_deleted'    => $this->mDeleted,
 925                                 'rev_len'        => $this->mSize,
 926                                 'rev_parent_id'  => is_null( $this->mParentId )
 927                                         ? $this->getPreviousRevisionId( $dbw )
 928                                         : $this->mParentId,
 929                                 'rev_sha1'       => is_null( $this->mSha1 )
 930                                         ? Revision::base36Sha1( $this->mText )
 931                                         : $this->mSha1
 932                         ), __METHOD__
 933                 );
 934
 935                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
 936
 937                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 938
 939                 wfProfileOut( __METHOD__ );
 940                 return $this->mId;
 941         }
 942
 943         /**
 944          * Get the base 36 SHA-1 value for a string of text
 945          * @param $text String
 946          * @return String
 947          */
 948         public static function base36Sha1( $text ) {
 949                 return wfBaseConvert( sha1( $text ), 16, 36, 31 );
 950         }
 951
 952         /**
 953          * Lazy-load the revision's text.
 954          * Currently hardcoded to the 'text' table storage engine.
 955          *
 956          * @return String
 957          */
 958         protected function loadText() {
 959                 wfProfileIn( __METHOD__ );
 960
 961                 // Caching may be beneficial for massive use of external storage
 962                 global $wgRevisionCacheExpiry, $wgMemc;
 963                 $textId = $this->getTextId();
 964                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
 965                 if( $wgRevisionCacheExpiry ) {
 966                         $text = $wgMemc->get( $key );
 967                         if( is_string( $text ) ) {
 968                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
 969                                 wfProfileOut( __METHOD__ );
 970                                 return $text;
 971                         }
 972                 }
 973
 974                 // If we kept data for lazy extraction, use it now...
 975                 if ( isset( $this->mTextRow ) ) {
 976                         $row = $this->mTextRow;
 977                         $this->mTextRow = null;
 978                 } else {
 979                         $row = null;
 980                 }
 981
 982                 if( !$row ) {
 983                         // Text data is immutable; check slaves first.
 984                         $dbr = wfGetDB( DB_SLAVE );
 985                         $row = $dbr->selectRow( 'text',
 986                                 array( 'old_text', 'old_flags' ),
 987                                 array( 'old_id' => $this->getTextId() ),
 988                                 __METHOD__ );
 989                 }
 990
 991                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
 992                         // Possible slave lag!
 993                         $dbw = wfGetDB( DB_MASTER );
 994                         $row = $dbw->selectRow( 'text',
 995                                 array( 'old_text', 'old_flags' ),
 996                                 array( 'old_id' => $this->getTextId() ),
 997                                 __METHOD__ );
 998                 }
 999
1000                 $text = self::getRevisionText( $row );
1001
1002                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1003                 if( $wgRevisionCacheExpiry && $text !== false ) {
1004                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
1005                 }
1006
1007                 wfProfileOut( __METHOD__ );
1008
1009                 return $text;
1010         }
1011
1012         /**
1013          * Create a new null-revision for insertion into a page's
1014          * history. This will not re-save the text, but simply refer
1015          * to the text from the previous version.
1016          *
1017          * Such revisions can for instance identify page rename
1018          * operations and other such meta-modifications.
1019          *
1020          * @param $dbw DatabaseBase
1021          * @param $pageId Integer: ID number of the page to read from
1022          * @param $summary String: revision's summary
1023          * @param $minor Boolean: whether the revision should be considered as minor
1024          * @return Revision|null on error
1025          */
1026         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
1027                 wfProfileIn( __METHOD__ );
1028
1029                 $current = $dbw->selectRow(
1030                         array( 'page', 'revision' ),
1031                         array( 'page_latest', 'rev_text_id', 'rev_len' ),
1032                         array(
1033                                 'page_id' => $pageId,
1034                                 'page_latest=rev_id',
1035                                 ),
1036                         __METHOD__ );
1037
1038                 if( $current ) {
1039                         $revision = new Revision( array(
1040                                 'page'       => $pageId,
1041                                 'comment'    => $summary,
1042                                 'minor_edit' => $minor,
1043                                 'text_id'    => $current->rev_text_id,
1044                                 'parent_id'  => $current->page_latest,
1045                                 'len'        => $current->rev_len
1046                                 ) );
1047                 } else {
1048                         $revision = null;
1049                 }
1050
1051                 wfProfileOut( __METHOD__ );
1052                 return $revision;
1053         }
1054
1055         /**
1056          * Determine if the current user is allowed to view a particular
1057          * field of this revision, if it's marked as deleted.
1058          *
1059          * @param $field Integer:one of self::DELETED_TEXT,
1060          *                              self::DELETED_COMMENT,
1061          *                              self::DELETED_USER
1062          * @return Boolean
1063          */
1064         public function userCan( $field ) {
1065                 return self::userCanBitfield( $this->mDeleted, $field );
1066         }
1067
1068         /**
1069          * Determine if the current user is allowed to view a particular
1070          * field of this revision, if it's marked as deleted. This is used
1071          * by various classes to avoid duplication.
1072          *
1073          * @param $bitfield Integer: current field
1074          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1075          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1076          *                               self::DELETED_USER = File::DELETED_USER
1077          * @return Boolean
1078          */
1079         public static function userCanBitfield( $bitfield, $field ) {
1080                 if( $bitfield & $field ) { // aspect is deleted
1081                         global $wgUser;
1082                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1083                                 $permission = 'suppressrevision';
1084                         } elseif ( $field & self::DELETED_TEXT ) {
1085                                 $permission = 'deletedtext';
1086                         } else {
1087                                 $permission = 'deletedhistory';
1088                         }
1089                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1090                         return $wgUser->isAllowed( $permission );
1091                 } else {
1092                         return true;
1093                 }
1094         }
1095
1096         /**
1097          * Get rev_timestamp from rev_id, without loading the rest of the row
1098          *
1099          * @param $title Title
1100          * @param $id Integer
1101          * @return String
1102          */
1103         static function getTimestampFromId( $title, $id ) {
1104                 $dbr = wfGetDB( DB_SLAVE );
1105                 // Casting fix for DB2
1106                 if ( $id == '' ) {
1107                         $id = 0;
1108                 }
1109                 $conds = array( 'rev_id' => $id );
1110                 $conds['rev_page'] = $title->getArticleId();
1111                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1112                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1113                         # Not in slave, try master
1114                         $dbw = wfGetDB( DB_MASTER );
1115                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1116                 }
1117                 return wfTimestamp( TS_MW, $timestamp );
1118         }
1119
1120         /**
1121          * Get count of revisions per page...not very efficient
1122          *
1123          * @param $db DatabaseBase
1124          * @param $id Integer: page id
1125          * @return Integer
1126          */
1127         static function countByPageId( $db, $id ) {
1128                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1129                         array( 'rev_page' => $id ), __METHOD__ );
1130                 if( $row ) {
1131                         return $row->revCount;
1132                 }
1133                 return 0;
1134         }
1135
1136         /**
1137          * Get count of revisions per page...not very efficient
1138          *
1139          * @param $db DatabaseBase
1140          * @param $title Title
1141          * @return Integer
1142          */
1143         static function countByTitle( $db, $title ) {
1144                 $id = $title->getArticleId();
1145                 if( $id ) {
1146                         return Revision::countByPageId( $db, $id );
1147                 }
1148                 return 0;
1149         }
1150 }