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