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( array( 'rev_id' => intval( $id ) ) );
  27         }
  28
  29         /**
  30          * Load either the current, or a specified, revision
  31          * that's attached to a given title. If not attached
  32          * to that title, will return null.
  33          *
  34          * @param $title Title
  35          * @param $id Integer (optional)
  36          * @return Revision or null
  37          */
  38         public static function newFromTitle( $title, $id = 0 ) {
  39                 $conds = array(
  40                         'page_namespace' => $title->getNamespace(),
  41                         'page_title'     => $title->getDBkey()
  42                 );
  43                 if ( $id ) {
  44                         // Use the specified ID
  45                         $conds['rev_id'] = $id;
  46                 } elseif ( wfGetLB()->getServerCount() > 1 ) {
  47                         // Get the latest revision ID from the master
  48                         $dbw = wfGetDB( DB_MASTER );
  49                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
  50                         if ( $latest === false ) {
  51                                 return null; // page does not exist
  52                         }
  53                         $conds['rev_id'] = $latest;
  54                 } else {
  55                         // Use a join to get the latest revision
  56                         $conds[] = 'rev_id=page_latest';
  57                 }
  58                 return Revision::newFromConds( $conds );
  59         }
  60
  61         /**
  62          * Load either the current, or a specified, revision
  63          * that's attached to a given page ID.
  64          * Returns null if no such revision can be found.
  65          *
  66          * @param $revId Integer
  67          * @param $pageId Integer (optional)
  68          * @return Revision or null
  69          */
  70         public static function newFromPageId( $pageId, $revId = 0 ) {
  71                 $conds = array( 'page_id' => $pageId );
  72                 if ( $revId ) {
  73                         $conds['rev_id'] = $revId;
  74                 } elseif ( wfGetLB()->getServerCount() > 1 ) {
  75                         // Get the latest revision ID from the master
  76                         $dbw = wfGetDB( DB_MASTER );
  77                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
  78                         if ( $latest === false ) {
  79                                 return null; // page does not exist
  80                         }
  81                         $conds['rev_id'] = $latest;
  82                 } else {
  83                         $conds[] = 'rev_id = page_latest';
  84                 }
  85                 return Revision::newFromConds( $conds );
  86         }
  87
  88         /**
  89          * Make a fake revision object from an archive table row. This is queried
  90          * for permissions or even inserted (as in Special:Undelete)
  91          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
  92          *
  93          * @param $row
  94          * @param $overrides array
  95          *
  96          * @return Revision
  97          */
  98         public static function newFromArchiveRow( $row, $overrides = array() ) {
  99                 $attribs = $overrides + array(
 100                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 101                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 102                         'comment'    => $row->ar_comment,
 103                         'user'       => $row->ar_user,
 104                         'user_text'  => $row->ar_user_text,
 105                         'timestamp'  => $row->ar_timestamp,
 106                         'minor_edit' => $row->ar_minor_edit,
 107                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 108                         'deleted'    => $row->ar_deleted,
 109                         'len'        => $row->ar_len
 110                 );
 111                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 112                         // Pre-1.5 ar_text row
 113                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 114                         if ( $attribs['text'] === false ) {
 115                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 116                         }
 117                 }
 118                 return new self( $attribs );
 119         }
 120
 121         /**
 122          * @since 1.19
 123          *
 124          * @param $row
 125          * @return Revision
 126          */
 127         public static function newFromRow( $row ) {
 128                 return new self( $row );
 129         }
 130
 131         /**
 132          * Load a page revision from a given revision ID number.
 133          * Returns null if no such revision can be found.
 134          *
 135          * @param $db DatabaseBase
 136          * @param $id Integer
 137          * @return Revision or null
 138          */
 139         public static function loadFromId( $db, $id ) {
 140                 return Revision::loadFromConds( $db, array( 'rev_id' => intval( $id ) ) );
 141         }
 142
 143         /**
 144          * Load either the current, or a specified, revision
 145          * that's attached to a given page. If not attached
 146          * to that page, will return null.
 147          *
 148          * @param $db DatabaseBase
 149          * @param $pageid Integer
 150          * @param $id Integer
 151          * @return Revision or null
 152          */
 153         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 154                 $conds = array( 'rev_page' => intval( $pageid ), 'page_id'  => intval( $pageid ) );
 155                 if( $id ) {
 156                         $conds['rev_id'] = intval( $id );
 157                 } else {
 158                         $conds[] = 'rev_id=page_latest';
 159                 }
 160                 return Revision::loadFromConds( $db, $conds );
 161         }
 162
 163         /**
 164          * Load either the current, or a specified, revision
 165          * that's attached to a given page. If not attached
 166          * to that page, will return null.
 167          *
 168          * @param $db DatabaseBase
 169          * @param $title Title
 170          * @param $id Integer
 171          * @return Revision or null
 172          */
 173         public static function loadFromTitle( $db, $title, $id = 0 ) {
 174                 if( $id ) {
 175                         $matchId = intval( $id );
 176                 } else {
 177                         $matchId = 'page_latest';
 178                 }
 179                 return Revision::loadFromConds( $db,
 180                         array( "rev_id=$matchId",
 181                                    'page_namespace' => $title->getNamespace(),
 182                                    'page_title'     => $title->getDBkey() )
 183                 );
 184         }
 185
 186         /**
 187          * Load the revision for the given title with the given timestamp.
 188          * WARNING: Timestamps may in some circumstances not be unique,
 189          * so this isn't the best key to use.
 190          *
 191          * @param $db DatabaseBase
 192          * @param $title Title
 193          * @param $timestamp String
 194          * @return Revision or null
 195          */
 196         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 197                 return Revision::loadFromConds( $db,
 198                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 199                                    'page_namespace' => $title->getNamespace(),
 200                                    'page_title'     => $title->getDBkey() )
 201                 );
 202         }
 203
 204         /**
 205          * Given a set of conditions, fetch a revision.
 206          *
 207          * @param $conditions Array
 208          * @return Revision or null
 209          */
 210         public static function newFromConds( $conditions ) {
 211                 $db = wfGetDB( DB_SLAVE );
 212                 $rev = Revision::loadFromConds( $db, $conditions );
 213                 if( is_null( $rev ) && wfGetLB()->getServerCount() > 1 ) {
 214                         $dbw = wfGetDB( DB_MASTER );
 215                         $rev = Revision::loadFromConds( $dbw, $conditions );
 216                 }
 217                 return $rev;
 218         }
 219
 220         /**
 221          * Given a set of conditions, fetch a revision from
 222          * the given database connection.
 223          *
 224          * @param $db DatabaseBase
 225          * @param $conditions Array
 226          * @return Revision or null
 227          */
 228         private static function loadFromConds( $db, $conditions ) {
 229                 $res = Revision::fetchFromConds( $db, $conditions );
 230                 if( $res ) {
 231                         $row = $res->fetchObject();
 232                         if( $row ) {
 233                                 $ret = new Revision( $row );
 234                                 return $ret;
 235                         }
 236                 }
 237                 $ret = null;
 238                 return $ret;
 239         }
 240
 241         /**
 242          * Return a wrapper for a series of database rows to
 243          * fetch all of a given page's revisions in turn.
 244          * Each row can be fed to the constructor to get objects.
 245          *
 246          * @param $title Title
 247          * @return ResultWrapper
 248          */
 249         public static function fetchRevision( $title ) {
 250                 return Revision::fetchFromConds(
 251                         wfGetDB( DB_SLAVE ),
 252                         array( 'rev_id=page_latest',
 253                                    'page_namespace' => $title->getNamespace(),
 254                                    'page_title'     => $title->getDBkey() )
 255                 );
 256         }
 257
 258         /**
 259          * Given a set of conditions, return a ResultWrapper
 260          * which will return matching database rows with the
 261          * fields necessary to build Revision objects.
 262          *
 263          * @param $db DatabaseBase
 264          * @param $conditions Array
 265          * @return ResultWrapper
 266          */
 267         private static function fetchFromConds( $db, $conditions ) {
 268                 $fields = array_merge(
 269                         self::selectFields(),
 270                         self::selectPageFields(),
 271                         self::selectUserFields()
 272                 );
 273                 return $db->select(
 274                         array( 'revision', 'page', 'user' ),
 275                         $fields,
 276                         $conditions,
 277                         __METHOD__,
 278                         array( 'LIMIT' => 1 ),
 279                         array( 'page' => array( 'INNER JOIN', 'page_id = rev_page' ),
 280                                 'user' => array( 'LEFT JOIN', 'user_id = rev_user' ) )
 281                 );
 282         }
 283
 284         /**
 285          * Return the list of revision fields that should be selected to create
 286          * a new revision.
 287          */
 288         public static function selectFields() {
 289                 return array(
 290                         'rev_id',
 291                         'rev_page',
 292                         'rev_text_id',
 293                         'rev_timestamp',
 294                         'rev_comment',
 295                         'rev_user_text',
 296                         'rev_user',
 297                         'rev_minor_edit',
 298                         'rev_deleted',
 299                         'rev_len',
 300                         'rev_parent_id'
 301                 );
 302         }
 303
 304         /**
 305          * Return the list of text fields that should be selected to read the
 306          * revision text
 307          */
 308         static function selectTextFields() {
 309                 return array(
 310                         'old_text',
 311                         'old_flags'
 312                 );
 313         }
 314
 315         /**
 316          * Return the list of page fields that should be selected from page table
 317          */
 318         static function selectPageFields() {
 319                 return array(
 320                         'page_namespace',
 321                         'page_title',
 322                         'page_latest'
 323                 );
 324         }
 325
 326         /**
 327          * Return the list of user fields that should be selected from user table
 328          */
 329         static function selectUserFields() {
 330                 return array( 'COALESCE(user_name,rev_user_text) AS rev_user_name' );
 331         }
 332
 333         /**
 334          * Constructor
 335          *
 336          * @param $row Mixed: either a database row or an array
 337          * @access private
 338          */
 339         function __construct( $row ) {
 340                 if( is_object( $row ) ) {
 341                         $this->mId        = intval( $row->rev_id );
 342                         $this->mPage      = intval( $row->rev_page );
 343                         $this->mTextId    = intval( $row->rev_text_id );
 344                         $this->mComment   =         $row->rev_comment;
 345                         $this->mUser      = intval( $row->rev_user );
 346                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 347                         $this->mTimestamp =         $row->rev_timestamp;
 348                         $this->mDeleted   = intval( $row->rev_deleted );
 349
 350                         if( !isset( $row->rev_parent_id ) ) {
 351                                 $this->mParentId = is_null($row->rev_parent_id) ? null : 0;
 352                         } else {
 353                                 $this->mParentId  = intval( $row->rev_parent_id );
 354                         }
 355
 356                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) ) {
 357                                 $this->mSize = null;
 358                         } else {
 359                                 $this->mSize = intval( $row->rev_len );
 360                         }
 361
 362                         if( isset( $row->page_latest ) ) {
 363                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 364                                 $this->mTitle = Title::newFromRow( $row );
 365                         } else {
 366                                 $this->mCurrent = false;
 367                                 $this->mTitle = null;
 368                         }
 369
 370                         // Lazy extraction...
 371                         $this->mText      = null;
 372                         if( isset( $row->old_text ) ) {
 373                                 $this->mTextRow = $row;
 374                         } else {
 375                                 // 'text' table row entry will be lazy-loaded
 376                                 $this->mTextRow = null;
 377                         }
 378
 379                         if ( isset( $row->rev_user_name ) ) {
 380                                 $this->mUserText = $row->rev_user_name; // current user name
 381                         } else { // fallback to rev_user_text
 382                                 $this->mUserText = $row->rev_user_text; // de-normalized
 383                         }
 384                 } elseif( is_array( $row ) ) {
 385                         // Build a new revision to be saved...
 386                         global $wgUser;
 387
 388                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 389                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 390                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 391                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 392                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 393                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 394                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 395                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 396                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 397                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 398
 399                         // Enforce spacing trimming on supplied text
 400                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 401                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 402                         $this->mTextRow   = null;
 403
 404                         $this->mTitle     = null; # Load on demand if needed
 405                         $this->mCurrent   = false;
 406                         # If we still have no len_size, see it we have the text to figure it out
 407                         if ( !$this->mSize ) {
 408                                 $this->mSize      = is_null( $this->mText ) ? null : strlen( $this->mText );
 409                         }
 410                 } else {
 411                         throw new MWException( 'Revision constructor passed invalid row format.' );
 412                 }
 413                 $this->mUnpatrolled = null;
 414         }
 415
 416         /**
 417          * Get revision ID
 418          *
 419          * @return Integer
 420          */
 421         public function getId() {
 422                 return $this->mId;
 423         }
 424
 425         /**
 426          * Get text row ID
 427          *
 428          * @return Integer
 429          */
 430         public function getTextId() {
 431                 return $this->mTextId;
 432         }
 433
 434         /**
 435          * Get parent revision ID (the original previous page revision)
 436          *
 437          * @return Integer
 438          */
 439         public function getParentId() {
 440                 return $this->mParentId;
 441         }
 442
 443         /**
 444          * Returns the length of the text in this revision, or null if unknown.
 445          *
 446          * @return Integer
 447          */
 448         public function getSize() {
 449                 return $this->mSize;
 450         }
 451
 452         /**
 453          * Returns the title of the page associated with this entry.
 454          *
 455          * @return Title
 456          */
 457         public function getTitle() {
 458                 if( isset( $this->mTitle ) ) {
 459                         return $this->mTitle;
 460                 }
 461                 $dbr = wfGetDB( DB_SLAVE );
 462                 $row = $dbr->selectRow(
 463                         array( 'page', 'revision' ),
 464                         array( 'page_namespace', 'page_title' ),
 465                         array( 'page_id=rev_page',
 466                                    'rev_id' => $this->mId ),
 467                         'Revision::getTitle' );
 468                 if( $row ) {
 469                         $this->mTitle = Title::makeTitle( $row->page_namespace, $row->page_title );
 470                 }
 471                 return $this->mTitle;
 472         }
 473
 474         /**
 475          * Set the title of the revision
 476          *
 477          * @param $title Title
 478          */
 479         public function setTitle( $title ) {
 480                 $this->mTitle = $title;
 481         }
 482
 483         /**
 484          * Get the page ID
 485          *
 486          * @return Integer
 487          */
 488         public function getPage() {
 489                 return $this->mPage;
 490         }
 491
 492         /**
 493          * Fetch revision's user id if it's available to the specified audience.
 494          * If the specified audience does not have access to it, zero will be
 495          * returned.
 496          *
 497          * @param $audience Integer: one of:
 498          *      Revision::FOR_PUBLIC       to be displayed to all users
 499          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 500          *      Revision::RAW              get the ID regardless of permissions
 501          * @param $user User object to check for, only if FOR_THIS_USER is passed
 502          *              to the $audience parameter
 503          * @return Integer
 504          */
 505         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 506                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 507                         return 0;
 508                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 509                         return 0;
 510                 } else {
 511                         return $this->mUser;
 512                 }
 513         }
 514
 515         /**
 516          * Fetch revision's user id without regard for the current user's permissions
 517          *
 518          * @return String
 519          */
 520         public function getRawUser() {
 521                 return $this->mUser;
 522         }
 523
 524         /**
 525          * Fetch revision's username if it's available to the specified audience.
 526          * If the specified audience does not have access to the username, an
 527          * empty string will be returned.
 528          *
 529          * @param $audience Integer: one of:
 530          *      Revision::FOR_PUBLIC       to be displayed to all users
 531          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 532          *      Revision::RAW              get the text regardless of permissions
 533          * @param $user User object to check for, only if FOR_THIS_USER is passed
 534          *              to the $audience parameter
 535          * @return string
 536          */
 537         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 538                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 539                         return '';
 540                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 541                         return '';
 542                 } else {
 543                         return $this->mUserText;
 544                 }
 545         }
 546
 547         /**
 548          * Fetch revision's username without regard for view restrictions
 549          *
 550          * @return String
 551          */
 552         public function getRawUserText() {
 553                 return $this->mUserText;
 554         }
 555
 556         /**
 557          * Fetch revision comment if it's available to the specified audience.
 558          * If the specified audience does not have access to the comment, an
 559          * empty string will be returned.
 560          *
 561          * @param $audience Integer: one of:
 562          *      Revision::FOR_PUBLIC       to be displayed to all users
 563          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 564          *      Revision::RAW              get the text regardless of permissions
 565          * @param $user User object to check for, only if FOR_THIS_USER is passed
 566          *              to the $audience parameter
 567          * @return String
 568          */
 569         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 570                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 571                         return '';
 572                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 573                         return '';
 574                 } else {
 575                         return $this->mComment;
 576                 }
 577         }
 578
 579         /**
 580          * Fetch revision comment without regard for the current user's permissions
 581          *
 582          * @return String
 583          */
 584         public function getRawComment() {
 585                 return $this->mComment;
 586         }
 587
 588         /**
 589          * @return Boolean
 590          */
 591         public function isMinor() {
 592                 return (bool)$this->mMinorEdit;
 593         }
 594
 595         /**
 596          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 597          */
 598         public function isUnpatrolled() {
 599                 if( $this->mUnpatrolled !== null ) {
 600                         return $this->mUnpatrolled;
 601                 }
 602                 $dbr = wfGetDB( DB_SLAVE );
 603                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 604                         'rc_id',
 605                         array( // Add redundant user,timestamp condition so we can use the existing index
 606                                 'rc_user_text'  => $this->getRawUserText(),
 607                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 608                                 'rc_this_oldid' => $this->getId(),
 609                                 'rc_patrolled'  => 0
 610                         ),
 611                         __METHOD__
 612                 );
 613                 return (int)$this->mUnpatrolled;
 614         }
 615
 616         /**
 617          * @param $field int one of DELETED_* bitfield constants
 618          *
 619          * @return Boolean
 620          */
 621         public function isDeleted( $field ) {
 622                 return ( $this->mDeleted & $field ) == $field;
 623         }
 624
 625         /**
 626          * Get the deletion bitfield of the revision
 627          *
 628          * @return int
 629          */
 630         public function getVisibility() {
 631                 return (int)$this->mDeleted;
 632         }
 633
 634         /**
 635          * Fetch revision text if it's available to the specified audience.
 636          * If the specified audience does not have the ability to view this
 637          * revision, an empty string will be returned.
 638          *
 639          * @param $audience Integer: one of:
 640          *      Revision::FOR_PUBLIC       to be displayed to all users
 641          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 642          *      Revision::RAW              get the text regardless of permissions
 643          * @param $user User object to check for, only if FOR_THIS_USER is passed
 644          *              to the $audience parameter
 645          * @return String
 646          */
 647         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
 648                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 649                         return '';
 650                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
 651                         return '';
 652                 } else {
 653                         return $this->getRawText();
 654                 }
 655         }
 656
 657         /**
 658          * Alias for getText(Revision::FOR_THIS_USER)
 659          *
 660          * @deprecated since 1.17
 661          * @return String
 662          */
 663         public function revText() {
 664                 wfDeprecated( __METHOD__ );
 665                 return $this->getText( self::FOR_THIS_USER );
 666         }
 667
 668         /**
 669          * Fetch revision text without regard for view restrictions
 670          *
 671          * @return String
 672          */
 673         public function getRawText() {
 674                 if( is_null( $this->mText ) ) {
 675                         // Revision text is immutable. Load on demand:
 676                         $this->mText = $this->loadText();
 677                 }
 678                 return $this->mText;
 679         }
 680
 681         /**
 682          * @return String
 683          */
 684         public function getTimestamp() {
 685                 return wfTimestamp( TS_MW, $this->mTimestamp );
 686         }
 687
 688         /**
 689          * @return Boolean
 690          */
 691         public function isCurrent() {
 692                 return $this->mCurrent;
 693         }
 694
 695         /**
 696          * Get previous revision for this title
 697          *
 698          * @return Revision or null
 699          */
 700         public function getPrevious() {
 701                 if( $this->getTitle() ) {
 702                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 703                         if( $prev ) {
 704                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 705                         }
 706                 }
 707                 return null;
 708         }
 709
 710         /**
 711          * Get next revision for this title
 712          *
 713          * @return Revision or null
 714          */
 715         public function getNext() {
 716                 if( $this->getTitle() ) {
 717                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 718                         if ( $next ) {
 719                                 return Revision::newFromTitle( $this->getTitle(), $next );
 720                         }
 721                 }
 722                 return null;
 723         }
 724
 725         /**
 726          * Get previous revision Id for this page_id
 727          * This is used to populate rev_parent_id on save
 728          *
 729          * @param $db DatabaseBase
 730          * @return Integer
 731          */
 732         private function getPreviousRevisionId( $db ) {
 733                 if( is_null( $this->mPage ) ) {
 734                         return 0;
 735                 }
 736                 # Use page_latest if ID is not given
 737                 if( !$this->mId ) {
 738                         $prevId = $db->selectField( 'page', 'page_latest',
 739                                 array( 'page_id' => $this->mPage ),
 740                                 __METHOD__ );
 741                 } else {
 742                         $prevId = $db->selectField( 'revision', 'rev_id',
 743                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 744                                 __METHOD__,
 745                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 746                 }
 747                 return intval( $prevId );
 748         }
 749
 750         /**
 751           * Get revision text associated with an old or archive row
 752           * $row is usually an object from wfFetchRow(), both the flags and the text
 753           * field must be included
 754           *
 755           * @param $row Object: the text data
 756           * @param $prefix String: table prefix (default 'old_')
 757           * @return String: text the text requested or false on failure
 758           */
 759         public static function getRevisionText( $row, $prefix = 'old_' ) {
 760                 wfProfileIn( __METHOD__ );
 761
 762                 # Get data
 763                 $textField = $prefix . 'text';
 764                 $flagsField = $prefix . 'flags';
 765
 766                 if( isset( $row->$flagsField ) ) {
 767                         $flags = explode( ',', $row->$flagsField );
 768                 } else {
 769                         $flags = array();
 770                 }
 771
 772                 if( isset( $row->$textField ) ) {
 773                         $text = $row->$textField;
 774                 } else {
 775                         wfProfileOut( __METHOD__ );
 776                         return false;
 777                 }
 778
 779                 # Use external methods for external objects, text in table is URL-only then
 780                 if ( in_array( 'external', $flags ) ) {
 781                         $url = $text;
 782                         $parts = explode( '://', $url, 2 );
 783                         if( count( $parts ) == 1 || $parts[1] == '' ) {
 784                                 wfProfileOut( __METHOD__ );
 785                                 return false;
 786                         }
 787                         $text = ExternalStore::fetchFromURL( $url );
 788                 }
 789
 790                 // If the text was fetched without an error, convert it
 791                 if ( $text !== false ) {
 792                         if( in_array( 'gzip', $flags ) ) {
 793                                 # Deal with optional compression of archived pages.
 794                                 # This can be done periodically via maintenance/compressOld.php, and
 795                                 # as pages are saved if $wgCompressRevisions is set.
 796                                 $text = gzinflate( $text );
 797                         }
 798
 799                         if( in_array( 'object', $flags ) ) {
 800                                 # Generic compressed storage
 801                                 $obj = unserialize( $text );
 802                                 if ( !is_object( $obj ) ) {
 803                                         // Invalid object
 804                                         wfProfileOut( __METHOD__ );
 805                                         return false;
 806                                 }
 807                                 $text = $obj->getText();
 808                         }
 809
 810                         global $wgLegacyEncoding;
 811                         if( $text !== false && $wgLegacyEncoding
 812                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
 813                         {
 814                                 # Old revisions kept around in a legacy encoding?
 815                                 # Upconvert on demand.
 816                                 # ("utf8" checked for compatibility with some broken
 817                                 #  conversion scripts 2008-12-30)
 818                                 global $wgContLang;
 819                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
 820                         }
 821                 }
 822                 wfProfileOut( __METHOD__ );
 823                 return $text;
 824         }
 825
 826         /**
 827          * If $wgCompressRevisions is enabled, we will compress data.
 828          * The input string is modified in place.
 829          * Return value is the flags field: contains 'gzip' if the
 830          * data is compressed, and 'utf-8' if we're saving in UTF-8
 831          * mode.
 832          *
 833          * @param $text Mixed: reference to a text
 834          * @return String
 835          */
 836         public static function compressRevisionText( &$text ) {
 837                 global $wgCompressRevisions;
 838                 $flags = array();
 839
 840                 # Revisions not marked this way will be converted
 841                 # on load if $wgLegacyCharset is set in the future.
 842                 $flags[] = 'utf-8';
 843
 844                 if( $wgCompressRevisions ) {
 845                         if( function_exists( 'gzdeflate' ) ) {
 846                                 $text = gzdeflate( $text );
 847                                 $flags[] = 'gzip';
 848                         } else {
 849                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 850                         }
 851                 }
 852                 return implode( ',', $flags );
 853         }
 854
 855         /**
 856          * Insert a new revision into the database, returning the new revision ID
 857          * number on success and dies horribly on failure.
 858          *
 859          * @param $dbw DatabaseBase: (master connection)
 860          * @return Integer
 861          */
 862         public function insertOn( $dbw ) {
 863                 global $wgDefaultExternalStore;
 864
 865                 wfProfileIn( __METHOD__ );
 866
 867                 $data = $this->mText;
 868                 $flags = Revision::compressRevisionText( $data );
 869
 870                 # Write to external storage if required
 871                 if( $wgDefaultExternalStore ) {
 872                         // Store and get the URL
 873                         $data = ExternalStore::insertToDefault( $data );
 874                         if( !$data ) {
 875                                 throw new MWException( "Unable to store text to external storage" );
 876                         }
 877                         if( $flags ) {
 878                                 $flags .= ',';
 879                         }
 880                         $flags .= 'external';
 881                 }
 882
 883                 # Record the text (or external storage URL) to the text table
 884                 if( !isset( $this->mTextId ) ) {
 885                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
 886                         $dbw->insert( 'text',
 887                                 array(
 888                                         'old_id'    => $old_id,
 889                                         'old_text'  => $data,
 890                                         'old_flags' => $flags,
 891                                 ), __METHOD__
 892                         );
 893                         $this->mTextId = $dbw->insertId();
 894                 }
 895
 896                 if ( $this->mComment === null ) $this->mComment = "";
 897
 898                 # Record the edit in revisions
 899                 $rev_id = isset( $this->mId )
 900                         ? $this->mId
 901                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
 902                 $dbw->insert( 'revision',
 903                         array(
 904                                 'rev_id'         => $rev_id,
 905                                 'rev_page'       => $this->mPage,
 906                                 'rev_text_id'    => $this->mTextId,
 907                                 'rev_comment'    => $this->mComment,
 908                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 909                                 'rev_user'       => $this->mUser,
 910                                 'rev_user_text'  => $this->mUserText,
 911                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 912                                 'rev_deleted'    => $this->mDeleted,
 913                                 'rev_len'        => $this->mSize,
 914                                 'rev_parent_id'  => is_null($this->mParentId) ?
 915                                         $this->getPreviousRevisionId( $dbw ) : $this->mParentId
 916                         ), __METHOD__
 917                 );
 918
 919                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
 920
 921                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 922
 923                 wfProfileOut( __METHOD__ );
 924                 return $this->mId;
 925         }
 926
 927         /**
 928          * Lazy-load the revision's text.
 929          * Currently hardcoded to the 'text' table storage engine.
 930          *
 931          * @return String
 932          */
 933         protected function loadText() {
 934                 wfProfileIn( __METHOD__ );
 935
 936                 // Caching may be beneficial for massive use of external storage
 937                 global $wgRevisionCacheExpiry, $wgMemc;
 938                 $textId = $this->getTextId();
 939                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
 940                 if( $wgRevisionCacheExpiry ) {
 941                         $text = $wgMemc->get( $key );
 942                         if( is_string( $text ) ) {
 943                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
 944                                 wfProfileOut( __METHOD__ );
 945                                 return $text;
 946                         }
 947                 }
 948
 949                 // If we kept data for lazy extraction, use it now...
 950                 if ( isset( $this->mTextRow ) ) {
 951                         $row = $this->mTextRow;
 952                         $this->mTextRow = null;
 953                 } else {
 954                         $row = null;
 955                 }
 956
 957                 if( !$row ) {
 958                         // Text data is immutable; check slaves first.
 959                         $dbr = wfGetDB( DB_SLAVE );
 960                         $row = $dbr->selectRow( 'text',
 961                                 array( 'old_text', 'old_flags' ),
 962                                 array( 'old_id' => $this->getTextId() ),
 963                                 __METHOD__ );
 964                 }
 965
 966                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
 967                         // Possible slave lag!
 968                         $dbw = wfGetDB( DB_MASTER );
 969                         $row = $dbw->selectRow( 'text',
 970                                 array( 'old_text', 'old_flags' ),
 971                                 array( 'old_id' => $this->getTextId() ),
 972                                 __METHOD__ );
 973                 }
 974
 975                 $text = self::getRevisionText( $row );
 976
 977                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
 978                 if( $wgRevisionCacheExpiry && $text !== false ) {
 979                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 980                 }
 981
 982                 wfProfileOut( __METHOD__ );
 983
 984                 return $text;
 985         }
 986
 987         /**
 988          * Create a new null-revision for insertion into a page's
 989          * history. This will not re-save the text, but simply refer
 990          * to the text from the previous version.
 991          *
 992          * Such revisions can for instance identify page rename
 993          * operations and other such meta-modifications.
 994          *
 995          * @param $dbw DatabaseBase
 996          * @param $pageId Integer: ID number of the page to read from
 997          * @param $summary String: revision's summary
 998          * @param $minor Boolean: whether the revision should be considered as minor
 999          * @return Revision|null on error
1000          */
1001         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
1002                 wfProfileIn( __METHOD__ );
1003
1004                 $current = $dbw->selectRow(
1005                         array( 'page', 'revision' ),
1006                         array( 'page_latest', 'rev_text_id', 'rev_len' ),
1007                         array(
1008                                 'page_id' => $pageId,
1009                                 'page_latest=rev_id',
1010                                 ),
1011                         __METHOD__ );
1012
1013                 if( $current ) {
1014                         $revision = new Revision( array(
1015                                 'page'       => $pageId,
1016                                 'comment'    => $summary,
1017                                 'minor_edit' => $minor,
1018                                 'text_id'    => $current->rev_text_id,
1019                                 'parent_id'  => $current->page_latest,
1020                                 'len'        => $current->rev_len
1021                                 ) );
1022                 } else {
1023                         $revision = null;
1024                 }
1025
1026                 wfProfileOut( __METHOD__ );
1027                 return $revision;
1028         }
1029
1030         /**
1031          * Determine if the current user is allowed to view a particular
1032          * field of this revision, if it's marked as deleted.
1033          *
1034          * @param $field Integer:one of self::DELETED_TEXT,
1035          *                              self::DELETED_COMMENT,
1036          *                              self::DELETED_USER
1037          * @param $user User object to check, or null to use $wgUser
1038          * @return Boolean
1039          */
1040         public function userCan( $field, User $user = null ) {
1041                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1042         }
1043
1044         /**
1045          * Determine if the current user is allowed to view a particular
1046          * field of this revision, if it's marked as deleted. This is used
1047          * by various classes to avoid duplication.
1048          *
1049          * @param $bitfield Integer: current field
1050          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1051          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1052          *                               self::DELETED_USER = File::DELETED_USER
1053          * @param $user User object to check, or null to use $wgUser
1054          * @return Boolean
1055          */
1056         public static function userCanBitfield( $bitfield, $field, User $user = null ) {
1057                 if( $bitfield & $field ) { // aspect is deleted
1058                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1059                                 $permission = 'suppressrevision';
1060                         } elseif ( $field & self::DELETED_TEXT ) {
1061                                 $permission = 'deletedtext';
1062                         } else {
1063                                 $permission = 'deletedhistory';
1064                         }
1065                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1066                         if ( $user === null ) {
1067                                 global $wgUser;
1068                                 $user = $wgUser;
1069                         }
1070                         return $user->isAllowed( $permission );
1071                 } else {
1072                         return true;
1073                 }
1074         }
1075
1076         /**
1077          * Get rev_timestamp from rev_id, without loading the rest of the row
1078          *
1079          * @param $title Title
1080          * @param $id Integer
1081          * @return String
1082          */
1083         static function getTimestampFromId( $title, $id ) {
1084                 $dbr = wfGetDB( DB_SLAVE );
1085                 // Casting fix for DB2
1086                 if ( $id == '' ) {
1087                         $id = 0;
1088                 }
1089                 $conds = array( 'rev_id' => $id );
1090                 $conds['rev_page'] = $title->getArticleId();
1091                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1092                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1093                         # Not in slave, try master
1094                         $dbw = wfGetDB( DB_MASTER );
1095                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1096                 }
1097                 return wfTimestamp( TS_MW, $timestamp );
1098         }
1099
1100         /**
1101          * Get count of revisions per page...not very efficient
1102          *
1103          * @param $db DatabaseBase
1104          * @param $id Integer: page id
1105          * @return Integer
1106          */
1107         static function countByPageId( $db, $id ) {
1108                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1109                         array( 'rev_page' => $id ), __METHOD__ );
1110                 if( $row ) {
1111                         return $row->revCount;
1112                 }
1113                 return 0;
1114         }
1115
1116         /**
1117          * Get count of revisions per page...not very efficient
1118          *
1119          * @param $db DatabaseBase
1120          * @param $title Title
1121          * @return Integer
1122          */
1123         static function countByTitle( $db, $title ) {
1124                 $id = $title->getArticleId();
1125                 if( $id ) {
1126                         return Revision::countByPageId( $db, $id );
1127                 }
1128                 return 0;
1129         }
1130 }