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