includes/Pager.php

   1 <?php
   2 /**
   3  * @defgroup Pager Pager
   4  *
   5  * @file
   6  * @ingroup Pager
   7  */
   8
   9 /**
  10  * Basic pager interface.
  11  * @ingroup Pager
  12  */
  13 interface Pager {
  14         function getNavigationBar();
  15         function getBody();
  16 }
  17
  18 /**
  19  * IndexPager is an efficient pager which uses a (roughly unique) index in the
  20  * data set to implement paging, rather than a "LIMIT offset,limit" clause.
  21  * In MySQL, such a limit/offset clause requires counting through the
  22  * specified number of offset rows to find the desired data, which can be
  23  * expensive for large offsets.
  24  *
  25  * ReverseChronologicalPager is a child class of the abstract IndexPager, and
  26  * contains  some formatting and display code which is specific to the use of
  27  * timestamps as  indexes. Here is a synopsis of its operation:
  28  *
  29  *    * The query is specified by the offset, limit and direction (dir)
  30  *      parameters, in addition to any subclass-specific parameters.
  31  *    * The offset is the non-inclusive start of the DB query. A row with an
  32  *      index value equal to the offset will never be shown.
  33  *    * The query may either be done backwards, where the rows are returned by
  34  *      the database in the opposite order to which they are displayed to the
  35  *      user, or forwards. This is specified by the "dir" parameter, dir=prev
  36  *      means backwards, anything else means forwards. The offset value
  37  *      specifies the start of the database result set, which may be either
  38  *      the start or end of the displayed data set. This allows "previous"
  39  *      links to be implemented without knowledge of the index value at the
  40  *      start of the previous page.
  41  *    * An additional row beyond the user-specified limit is always requested.
  42  *      This allows us to tell whether we should display a "next" link in the
  43  *      case of forwards mode, or a "previous" link in the case of backwards
  44  *      mode. Determining whether to display the other link (the one for the
  45  *      page before the start of the database result set) can be done
  46  *      heuristically by examining the offset.
  47  *
  48  *    * An empty offset indicates that the offset condition should be omitted
  49  *      from the query. This naturally produces either the first page or the
  50  *      last page depending on the dir parameter.
  51  *
  52  *  Subclassing the pager to implement concrete functionality should be fairly
  53  *  simple, please see the examples in PageHistory.php and
  54  *  SpecialIpblocklist.php. You just need to override formatRow(),
  55  *  getQueryInfo() and getIndexField(). Don't forget to call the parent
  56  *  constructor if you override it.
  57  *
  58  * @ingroup Pager
  59  */
  60 abstract class IndexPager implements Pager {
  61         public $mRequest;
  62         public $mLimitsShown = array( 20, 50, 100, 250, 500 );
  63         public $mDefaultLimit = 50;
  64         public $mOffset, $mLimit;
  65         public $mQueryDone = false;
  66         public $mDb;
  67         public $mPastTheEndRow;
  68
  69         /**
  70          * The index to actually be used for ordering.  This is a single string e-
  71          * ven if multiple orderings are supported.
  72          */
  73         protected $mIndexField;
  74         /** For pages that support multiple types of ordering, which one to use. */
  75         protected $mOrderType;
  76         /**
  77          * $mDefaultDirection gives the direction to use when sorting results:
  78          * false for ascending, true for descending.  If $mIsBackwards is set, we
  79          * start from the opposite end, but we still sort the page itself according
  80          * to $mDefaultDirection.  E.g., if $mDefaultDirection is false but we're
  81          * going backwards, we'll display the last page of results, but the last
  82          * result will be at the bottom, not the top.
  83          *
  84          * Like $mIndexField, $mDefaultDirection will be a single value even if the
  85          * class supports multiple default directions for different order types.
  86          */
  87         public $mDefaultDirection;
  88         public $mIsBackwards;
  89
  90         /**
  91          * Result object for the query. Warning: seek before use.
  92          */
  93         public $mResult;
  94
  95         public function __construct() {
  96                 global $wgRequest, $wgUser;
  97                 $this->mRequest = $wgRequest;
  98
  99                 # NB: the offset is quoted, not validated. It is treated as an
 100                 # arbitrary string to support the widest variety of index types. Be
 101                 # careful outputting it into HTML!
 102                 $this->mOffset = $this->mRequest->getText( 'offset' );
 103
 104                 # Use consistent behavior for the limit options
 105                 $this->mDefaultLimit = intval( $wgUser->getOption( 'rclimit' ) );
 106                 list( $this->mLimit, /* $offset */ ) = $this->mRequest->getLimitOffset();
 107
 108                 $this->mIsBackwards = ( $this->mRequest->getVal( 'dir' ) == 'prev' );
 109                 $this->mDb = wfGetDB( DB_SLAVE );
 110
 111                 $index = $this->getIndexField();
 112                 $order = $this->mRequest->getVal( 'order' );
 113                 if( is_array( $index ) && isset( $index[$order] ) ) {
 114                         $this->mOrderType = $order;
 115                         $this->mIndexField = $index[$order];
 116                 } elseif( is_array( $index ) ) {
 117                         # First element is the default
 118                         reset( $index );
 119                         list( $this->mOrderType, $this->mIndexField ) = each( $index );
 120                 } else {
 121                         # $index is not an array
 122                         $this->mOrderType = null;
 123                         $this->mIndexField = $index;
 124                 }
 125
 126                 if( !isset( $this->mDefaultDirection ) ) {
 127                         $dir = $this->getDefaultDirections();
 128                         $this->mDefaultDirection = is_array( $dir )
 129                                 ? $dir[$this->mOrderType]
 130                                 : $dir;
 131                 }
 132         }
 133
 134         /**
 135          * Do the query, using information from the object context. This function
 136          * has been kept minimal to make it overridable if necessary, to allow for
 137          * result sets formed from multiple DB queries.
 138          */
 139         function doQuery() {
 140                 # Use the child class name for profiling
 141                 $fname = __METHOD__ . ' (' . get_class( $this ) . ')';
 142                 wfProfileIn( $fname );
 143
 144                 $descending = ( $this->mIsBackwards == $this->mDefaultDirection );
 145                 # Plus an extra row so that we can tell the "next" link should be shown
 146                 $queryLimit = $this->mLimit + 1;
 147
 148                 $this->mResult = $this->reallyDoQuery( $this->mOffset, $queryLimit, $descending );
 149                 $this->extractResultInfo( $this->mOffset, $queryLimit, $this->mResult );
 150                 $this->mQueryDone = true;
 151
 152                 $this->preprocessResults( $this->mResult );
 153                 $this->mResult->rewind(); // Paranoia
 154
 155                 wfProfileOut( $fname );
 156         }
 157
 158         /**
 159          * Return the result wrapper.
 160          */
 161         function getResult() {
 162                 return $this->mResult;
 163         }
 164
 165         /**
 166          * Set the offset from an other source than $wgRequest
 167          */
 168         function setOffset( $offset ) {
 169                 $this->mOffset = $offset;
 170         }
 171         /**
 172          * Set the limit from an other source than $wgRequest
 173          */
 174         function setLimit( $limit ) {
 175                 $this->mLimit = $limit;
 176         }
 177
 178         /**
 179          * Extract some useful data from the result object for use by
 180          * the navigation bar, put it into $this
 181          */
 182         function extractResultInfo( $offset, $limit, ResultWrapper $res ) {
 183                 $numRows = $res->numRows();
 184                 if ( $numRows ) {
 185                         $row = $res->fetchRow();
 186                         $firstIndex = $row[$this->mIndexField];
 187
 188                         # Discard the extra result row if there is one
 189                         if ( $numRows > $this->mLimit && $numRows > 1 ) {
 190                                 $res->seek( $numRows - 1 );
 191                                 $this->mPastTheEndRow = $res->fetchObject();
 192                                 $indexField = $this->mIndexField;
 193                                 $this->mPastTheEndIndex = $this->mPastTheEndRow->$indexField;
 194                                 $res->seek( $numRows - 2 );
 195                                 $row = $res->fetchRow();
 196                                 $lastIndex = $row[$this->mIndexField];
 197                         } else {
 198                                 $this->mPastTheEndRow = null;
 199                                 # Setting indexes to an empty string means that they will be
 200                                 # omitted if they would otherwise appear in URLs. It just so
 201                                 # happens that this  is the right thing to do in the standard
 202                                 # UI, in all the relevant cases.
 203                                 $this->mPastTheEndIndex = '';
 204                                 $res->seek( $numRows - 1 );
 205                                 $row = $res->fetchRow();
 206                                 $lastIndex = $row[$this->mIndexField];
 207                         }
 208                 } else {
 209                         $firstIndex = '';
 210                         $lastIndex = '';
 211                         $this->mPastTheEndRow = null;
 212                         $this->mPastTheEndIndex = '';
 213                 }
 214
 215                 if ( $this->mIsBackwards ) {
 216                         $this->mIsFirst = ( $numRows < $limit );
 217                         $this->mIsLast = ( $offset == '' );
 218                         $this->mLastShown = $firstIndex;
 219                         $this->mFirstShown = $lastIndex;
 220                 } else {
 221                         $this->mIsFirst = ( $offset == '' );
 222                         $this->mIsLast = ( $numRows < $limit );
 223                         $this->mLastShown = $lastIndex;
 224                         $this->mFirstShown = $firstIndex;
 225                 }
 226         }
 227
 228         /**
 229          * Do a query with specified parameters, rather than using the object
 230          * context
 231          *
 232          * @param string $offset Index offset, inclusive
 233          * @param integer $limit Exact query limit
 234          * @param boolean $descending Query direction, false for ascending, true for descending
 235          * @return ResultWrapper
 236          */
 237         function reallyDoQuery( $offset, $limit, $descending ) {
 238                 $fname = __METHOD__ . ' (' . get_class( $this ) . ')';
 239                 $info = $this->getQueryInfo();
 240                 $tables = $info['tables'];
 241                 $fields = $info['fields'];
 242                 $conds = isset( $info['conds'] ) ? $info['conds'] : array();
 243                 $options = isset( $info['options'] ) ? $info['options'] : array();
 244                 $join_conds = isset( $info['join_conds'] ) ? $info['join_conds'] : array();
 245                 if ( $descending ) {
 246                         $options['ORDER BY'] = $this->mIndexField;
 247                         $operator = '>';
 248                 } else {
 249                         $options['ORDER BY'] = $this->mIndexField . ' DESC';
 250                         $operator = '<';
 251                 }
 252                 if ( $offset != '' ) {
 253                         $conds[] = $this->mIndexField . $operator . $this->mDb->addQuotes( $offset );
 254                 }
 255                 $options['LIMIT'] = intval( $limit );
 256                 $res = $this->mDb->select( $tables, $fields, $conds, $fname, $options, $join_conds );
 257                 return new ResultWrapper( $this->mDb, $res );
 258         }
 259
 260         /**
 261          * Pre-process results; useful for performing batch existence checks, etc.
 262          *
 263          * @param ResultWrapper $result Result wrapper
 264          */
 265         protected function preprocessResults( $result ) {}
 266
 267         /**
 268          * Get the formatted result list. Calls getStartBody(), formatRow() and
 269          * getEndBody(), concatenates the results and returns them.
 270          */
 271         function getBody() {
 272                 if ( !$this->mQueryDone ) {
 273                         $this->doQuery();
 274                 }
 275                 # Don't use any extra rows returned by the query
 276                 $numRows = min( $this->mResult->numRows(), $this->mLimit );
 277
 278                 $s = $this->getStartBody();
 279                 if ( $numRows ) {
 280                         if ( $this->mIsBackwards ) {
 281                                 for ( $i = $numRows - 1; $i >= 0; $i-- ) {
 282                                         $this->mResult->seek( $i );
 283                                         $row = $this->mResult->fetchObject();
 284                                         $s .= $this->formatRow( $row );
 285                                 }
 286                         } else {
 287                                 $this->mResult->seek( 0 );
 288                                 for ( $i = 0; $i < $numRows; $i++ ) {
 289                                         $row = $this->mResult->fetchObject();
 290                                         $s .= $this->formatRow( $row );
 291                                 }
 292                         }
 293                 } else {
 294                         $s .= $this->getEmptyBody();
 295                 }
 296                 $s .= $this->getEndBody();
 297                 return $s;
 298         }
 299
 300         /**
 301          * Make a self-link
 302          */
 303         function makeLink($text, $query = null, $type=null) {
 304                 if ( $query === null ) {
 305                         return $text;
 306                 }
 307
 308                 $attrs = array();
 309                 if( in_array( $type, array( 'first', 'prev', 'next', 'last' ) ) ) {
 310                         # HTML5 rel attributes
 311                         $attrs['rel'] = $type;
 312                 }
 313
 314                 if( $type ) {
 315                         $attrs['class'] = "mw-{$type}link";
 316                 }
 317                 return $this->getSkin()->link( $this->getTitle(), $text,
 318                         $attrs, $query + $this->getDefaultQuery(), array('noclasses','known') );
 319         }
 320
 321         /**
 322          * Hook into getBody(), allows text to be inserted at the start. This
 323          * will be called even if there are no rows in the result set.
 324          */
 325         function getStartBody() {
 326                 return '';
 327         }
 328
 329         /**
 330          * Hook into getBody() for the end of the list
 331          */
 332         function getEndBody() {
 333                 return '';
 334         }
 335
 336         /**
 337          * Hook into getBody(), for the bit between the start and the
 338          * end when there are no rows
 339          */
 340         function getEmptyBody() {
 341                 return '';
 342         }
 343
 344         /**
 345          * Title used for self-links. Override this if you want to be able to
 346          * use a title other than $wgTitle
 347          */
 348         function getTitle() {
 349                 return $GLOBALS['wgTitle'];
 350         }
 351
 352         /**
 353          * Get the current skin. This can be overridden if necessary.
 354          */
 355         function getSkin() {
 356                 if ( !isset( $this->mSkin ) ) {
 357                         global $wgUser;
 358                         $this->mSkin = $wgUser->getSkin();
 359                 }
 360                 return $this->mSkin;
 361         }
 362
 363         /**
 364          * Get an array of query parameters that should be put into self-links.
 365          * By default, all parameters passed in the URL are used, except for a
 366          * short blacklist.
 367          */
 368         function getDefaultQuery() {
 369                 if ( !isset( $this->mDefaultQuery ) ) {
 370                         $this->mDefaultQuery = $_GET;
 371                         unset( $this->mDefaultQuery['title'] );
 372                         unset( $this->mDefaultQuery['dir'] );
 373                         unset( $this->mDefaultQuery['offset'] );
 374                         unset( $this->mDefaultQuery['limit'] );
 375                         unset( $this->mDefaultQuery['order'] );
 376                         unset( $this->mDefaultQuery['month'] );
 377                         unset( $this->mDefaultQuery['year'] );
 378                 }
 379                 return $this->mDefaultQuery;
 380         }
 381
 382         /**
 383          * Get the number of rows in the result set
 384          */
 385         function getNumRows() {
 386                 if ( !$this->mQueryDone ) {
 387                         $this->doQuery();
 388                 }
 389                 return $this->mResult->numRows();
 390         }
 391
 392         /**
 393          * Get a URL query array for the prev, next, first and last links.
 394          */
 395         function getPagingQueries() {
 396                 if ( !$this->mQueryDone ) {
 397                         $this->doQuery();
 398                 }
 399
 400                 # Don't announce the limit everywhere if it's the default
 401                 $urlLimit = $this->mLimit == $this->mDefaultLimit ? '' : $this->mLimit;
 402
 403                 if ( $this->mIsFirst ) {
 404                         $prev = false;
 405                         $first = false;
 406                 } else {
 407                         $prev = array( 'dir' => 'prev', 'offset' => $this->mFirstShown, 'limit' => $urlLimit );
 408                         $first = array( 'limit' => $urlLimit );
 409                 }
 410                 if ( $this->mIsLast ) {
 411                         $next = false;
 412                         $last = false;
 413                 } else {
 414                         $next = array( 'offset' => $this->mLastShown, 'limit' => $urlLimit );
 415                         $last = array( 'dir' => 'prev', 'limit' => $urlLimit );
 416                 }
 417                 return array( 'prev' => $prev, 'next' => $next, 'first' => $first, 'last' => $last );
 418         }
 419
 420         /**
 421          * Get paging links. If a link is disabled, the item from $disabledTexts
 422          * will be used. If there is no such item, the unlinked text from
 423          * $linkTexts will be used. Both $linkTexts and $disabledTexts are arrays
 424          * of HTML.
 425          */
 426         function getPagingLinks( $linkTexts, $disabledTexts = array() ) {
 427                 $queries = $this->getPagingQueries();
 428                 $links = array();
 429                 foreach ( $queries as $type => $query ) {
 430                         if ( $query !== false ) {
 431                                 $links[$type] = $this->makeLink( $linkTexts[$type], $queries[$type], $type );
 432                         } elseif ( isset( $disabledTexts[$type] ) ) {
 433                                 $links[$type] = $disabledTexts[$type];
 434                         } else {
 435                                 $links[$type] = $linkTexts[$type];
 436                         }
 437                 }
 438                 return $links;
 439         }
 440
 441         function getLimitLinks() {
 442                 global $wgLang;
 443                 $links = array();
 444                 if ( $this->mIsBackwards ) {
 445                         $offset = $this->mPastTheEndIndex;
 446                 } else {
 447                         $offset = $this->mOffset;
 448                 }
 449                 foreach ( $this->mLimitsShown as $limit ) {
 450                         $links[] = $this->makeLink( $wgLang->formatNum( $limit ),
 451                                 array( 'offset' => $offset, 'limit' => $limit ), 'num' );
 452                 }
 453                 return $links;
 454         }
 455
 456         /**
 457          * Abstract formatting function. This should return an HTML string
 458          * representing the result row $row. Rows will be concatenated and
 459          * returned by getBody()
 460          */
 461         abstract function formatRow( $row );
 462
 463         /**
 464          * This function should be overridden to provide all parameters
 465          * needed for the main paged query. It returns an associative
 466          * array with the following elements:
 467          *    tables => Table(s) for passing to Database::select()
 468          *    fields => Field(s) for passing to Database::select(), may be *
 469          *    conds => WHERE conditions
 470          *    options => option array
 471          *    join_conds => JOIN conditions
 472          */
 473         abstract function getQueryInfo();
 474
 475         /**
 476          * This function should be overridden to return the name of the index fi-
 477          * eld.  If the pager supports multiple orders, it may return an array of
 478          * 'querykey' => 'indexfield' pairs, so that a request with &count=querykey
 479          * will use indexfield to sort.  In this case, the first returned key is
 480          * the default.
 481          *
 482          * Needless to say, it's really not a good idea to use a non-unique index
 483          * for this!  That won't page right.
 484          */
 485         abstract function getIndexField();
 486
 487         /**
 488          * Return the default sorting direction: false for ascending, true for de-
 489          * scending.  You can also have an associative array of ordertype => dir,
 490          * if multiple order types are supported.  In this case getIndexField()
 491          * must return an array, and the keys of that must exactly match the keys
 492          * of this.
 493          *
 494          * For backward compatibility, this method's return value will be ignored
 495          * if $this->mDefaultDirection is already set when the constructor is
 496          * called, for instance if it's statically initialized.  In that case the
 497          * value of that variable (which must be a boolean) will be used.
 498          *
 499          * Note that despite its name, this does not return the value of the
 500          * $this->mDefaultDirection member variable.  That's the default for this
 501          * particular instantiation, which is a single value.  This is the set of
 502          * all defaults for the class.
 503          */
 504         protected function getDefaultDirections() { return false; }
 505 }
 506
 507
 508 /**
 509  * IndexPager with an alphabetic list and a formatted navigation bar
 510  * @ingroup Pager
 511  */
 512 abstract class AlphabeticPager extends IndexPager {
 513         /**
 514          * Shamelessly stolen bits from ReverseChronologicalPager,
 515          * didn't want to do class magic as may be still revamped
 516          */
 517         function getNavigationBar() {
 518                 global $wgLang;
 519
 520                 if( isset( $this->mNavigationBar ) ) {
 521                         return $this->mNavigationBar;
 522                 }
 523
 524                 $opts = array( 'parsemag', 'escapenoentities' );
 525                 $linkTexts = array(
 526                         'prev' => wfMsgExt( 'prevn', $opts, $wgLang->formatNum( $this->mLimit ) ),
 527                         'next' => wfMsgExt( 'nextn', $opts, $wgLang->formatNum($this->mLimit ) ),
 528                         'first' => wfMsgExt( 'page_first', $opts ),
 529                         'last' => wfMsgExt( 'page_last', $opts )
 530                 );
 531
 532                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 533                 $limitLinks = $this->getLimitLinks();
 534                 $limits = $wgLang->pipeList( $limitLinks );
 535
 536                 $this->mNavigationBar =
 537                         "(" . $wgLang->pipeList( array( $pagingLinks['first'], $pagingLinks['last'] ) ) . ") " .
 538                         wfMsgHtml( 'viewprevnext', $pagingLinks['prev'],
 539                         $pagingLinks['next'], $limits );
 540
 541                 if( !is_array( $this->getIndexField() ) ) {
 542                         # Early return to avoid undue nesting
 543                         return $this->mNavigationBar;
 544                 }
 545
 546                 $extra = '';
 547                 $first = true;
 548                 $msgs = $this->getOrderTypeMessages();
 549                 foreach( array_keys( $msgs ) as $order ) {
 550                         if( $first ) {
 551                                 $first = false;
 552                         } else {
 553                                 $extra .= wfMsgExt( 'pipe-separator' , 'escapenoentities' );
 554                         }
 555
 556                         if( $order == $this->mOrderType ) {
 557                                 $extra .= wfMsgHTML( $msgs[$order] );
 558                         } else {
 559                                 $extra .= $this->makeLink(
 560                                         wfMsgHTML( $msgs[$order] ),
 561                                         array( 'order' => $order )
 562                                 );
 563                         }
 564                 }
 565
 566                 if( $extra !== '' ) {
 567                         $this->mNavigationBar .= " ($extra)";
 568                 }
 569
 570                 return $this->mNavigationBar;
 571         }
 572
 573         /**
 574          * If this supports multiple order type messages, give the message key for
 575          * enabling each one in getNavigationBar.  The return type is an associa-
 576          * tive array whose keys must exactly match the keys of the array returned
 577          * by getIndexField(), and whose values are message keys.
 578          * @return array
 579          */
 580         protected function getOrderTypeMessages() {
 581                 return null;
 582         }
 583 }
 584
 585 /**
 586  * IndexPager with a formatted navigation bar
 587  * @ingroup Pager
 588  */
 589 abstract class ReverseChronologicalPager extends IndexPager {
 590         public $mDefaultDirection = true;
 591         public $mYear;
 592         public $mMonth;
 593
 594         function __construct() {
 595                 parent::__construct();
 596         }
 597
 598         function getNavigationBar() {
 599                 global $wgLang;
 600
 601                 if ( isset( $this->mNavigationBar ) ) {
 602                         return $this->mNavigationBar;
 603                 }
 604                 $nicenumber = $wgLang->formatNum( $this->mLimit );
 605                 $linkTexts = array(
 606                         'prev' => wfMsgExt( 'pager-newer-n', array( 'parsemag' ), $nicenumber ),
 607                         'next' => wfMsgExt( 'pager-older-n', array( 'parsemag' ), $nicenumber ),
 608                         'first' => wfMsgHtml( 'histlast' ),
 609                         'last' => wfMsgHtml( 'histfirst' )
 610                 );
 611
 612                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 613                 $limitLinks = $this->getLimitLinks();
 614                 $limits = $wgLang->pipeList( $limitLinks );
 615
 616                 $this->mNavigationBar = "({$pagingLinks['first']}" . wfMsgExt( 'pipe-separator' , 'escapenoentities' ) . "{$pagingLinks['last']}) " .
 617                         wfMsgHtml("viewprevnext", $pagingLinks['prev'], $pagingLinks['next'], $limits);
 618                 return $this->mNavigationBar;
 619         }
 620
 621         function getDateCond( $year, $month ) {
 622                 $year = intval($year);
 623                 $month = intval($month);
 624                 // Basic validity checks
 625                 $this->mYear = $year > 0 ? $year : false;
 626                 $this->mMonth = ($month > 0 && $month < 13) ? $month : false;
 627                 // Given an optional year and month, we need to generate a timestamp
 628                 // to use as "WHERE rev_timestamp <= result"
 629                 // Examples: year = 2006 equals < 20070101 (+000000)
 630                 // year=2005, month=1    equals < 20050201
 631                 // year=2005, month=12   equals < 20060101
 632                 if ( !$this->mYear && !$this->mMonth ) {
 633                         return;
 634                 }
 635                 if ( $this->mYear ) {
 636                         $year = $this->mYear;
 637                 } else {
 638                         // If no year given, assume the current one
 639                         $year = gmdate( 'Y' );
 640                         // If this month hasn't happened yet this year, go back to last year's month
 641                         if( $this->mMonth > gmdate( 'n' ) ) {
 642                                 $year--;
 643                         }
 644                 }
 645                 if ( $this->mMonth ) {
 646                         $month = $this->mMonth + 1;
 647                         // For December, we want January 1 of the next year
 648                         if ($month > 12) {
 649                                 $month = 1;
 650                                 $year++;
 651                         }
 652                 } else {
 653                         // No month implies we want up to the end of the year in question
 654                         $month = 1;
 655                         $year++;
 656                 }
 657                 // Y2K38 bug
 658                 if ( $year > 2032 ) {
 659                         $year = 2032;
 660                 }
 661                 $ymd = (int)sprintf( "%04d%02d01", $year, $month );
 662                 if ( $ymd > 20320101 ) {
 663                         $ymd = 20320101;
 664                 }
 665                 $this->mOffset = $this->mDb->timestamp( "${ymd}000000" );
 666         }
 667 }
 668
 669 /**
 670  * Table-based display with a user-selectable sort order
 671  * @ingroup Pager
 672  */
 673 abstract class TablePager extends IndexPager {
 674         var $mSort;
 675         var $mCurrentRow;
 676
 677         function __construct() {
 678                 global $wgRequest;
 679                 $this->mSort = $wgRequest->getText( 'sort' );
 680                 if ( !array_key_exists( $this->mSort, $this->getFieldNames() ) ) {
 681                         $this->mSort = $this->getDefaultSort();
 682                 }
 683                 if ( $wgRequest->getBool( 'asc' ) ) {
 684                         $this->mDefaultDirection = false;
 685                 } elseif ( $wgRequest->getBool( 'desc' ) ) {
 686                         $this->mDefaultDirection = true;
 687                 } /* Else leave it at whatever the class default is */
 688
 689                 parent::__construct();
 690         }
 691
 692         function getStartBody() {
 693                 global $wgStylePath;
 694                 $tableClass = htmlspecialchars( $this->getTableClass() );
 695                 $sortClass = htmlspecialchars( $this->getSortHeaderClass() );
 696
 697                 $s = "<table border='1' class=\"$tableClass\"><thead><tr>\n";
 698                 $fields = $this->getFieldNames();
 699
 700                 # Make table header
 701                 foreach ( $fields as $field => $name ) {
 702                         if ( strval( $name ) == '' ) {
 703                                 $s .= "<th>&nbsp;</th>\n";
 704                         } elseif ( $this->isFieldSortable( $field ) ) {
 705                                 $query = array( 'sort' => $field, 'limit' => $this->mLimit );
 706                                 if ( $field == $this->mSort ) {
 707                                         # This is the sorted column
 708                                         # Prepare a link that goes in the other sort order
 709                                         if ( $this->mDefaultDirection ) {
 710                                                 # Descending
 711                                                 $image = 'Arr_u.png';
 712                                                 $query['asc'] = '1';
 713                                                 $query['desc'] = '';
 714                                                 $alt = htmlspecialchars( wfMsg( 'descending_abbrev' ) );
 715                                         } else {
 716                                                 # Ascending
 717                                                 $image = 'Arr_d.png';
 718                                                 $query['asc'] = '';
 719                                                 $query['desc'] = '1';
 720                                                 $alt = htmlspecialchars( wfMsg( 'ascending_abbrev' ) );
 721                                         }
 722                                         $image = htmlspecialchars( "$wgStylePath/common/images/$image" );
 723                                         $link = $this->makeLink(
 724                                                 "<img width=\"12\" height=\"12\" alt=\"$alt\" src=\"$image\" />" .
 725                                                 htmlspecialchars( $name ), $query );
 726                                         $s .= "<th class=\"$sortClass\">$link</th>\n";
 727                                 } else {
 728                                         $s .= '<th>' . $this->makeLink( htmlspecialchars( $name ), $query ) . "</th>\n";
 729                                 }
 730                         } else {
 731                                 $s .= '<th>' . htmlspecialchars( $name ) . "</th>\n";
 732                         }
 733                 }
 734                 $s .= "</tr></thead><tbody>\n";
 735                 return $s;
 736         }
 737
 738         function getEndBody() {
 739                 return "</tbody></table>\n";
 740         }
 741
 742         function getEmptyBody() {
 743                 $colspan = count( $this->getFieldNames() );
 744                 $msgEmpty = wfMsgHtml( 'table_pager_empty' );
 745                 return "<tr><td colspan=\"$colspan\">$msgEmpty</td></tr>\n";
 746         }
 747
 748         function formatRow( $row ) {
 749                 $rowClass = htmlspecialchars( $this->getRowClass( $row ) );
 750                 $s = "<tr class=\"$rowClass\">\n";
 751                 $fieldNames = $this->getFieldNames();
 752                 $this->mCurrentRow = $row;  # In case formatValue needs to know
 753                 foreach ( $fieldNames as $field => $name ) {
 754                         $value = isset( $row->$field ) ? $row->$field : null;
 755                         $formatted = strval( $this->formatValue( $field, $value ) );
 756                         if ( $formatted == '' ) {
 757                                 $formatted = '&nbsp;';
 758                         }
 759                         $class = 'TablePager_col_' . htmlspecialchars( $field );
 760                         $s .= "<td class=\"$class\">$formatted</td>\n";
 761                 }
 762                 $s .= "</tr>\n";
 763                 return $s;
 764         }
 765
 766         /**
 767          * Get a class name to be applied to the given row.
 768          * @param object $row The database result row
 769          */
 770         function getRowClass($row) {
 771                 return '';
 772         }
 773
 774         function getIndexField() {
 775                 return $this->mSort;
 776         }
 777
 778         function getTableClass() {
 779                 return 'TablePager';
 780         }
 781
 782         function getNavClass() {
 783                 return 'TablePager_nav';
 784         }
 785
 786         function getSortHeaderClass() {
 787                 return 'TablePager_sort';
 788         }
 789
 790         /**
 791          * A navigation bar with images
 792          */
 793         function getNavigationBar() {
 794                 global $wgStylePath, $wgContLang;
 795                 $path = "$wgStylePath/common/images";
 796                 $labels = array(
 797                         'first' => 'table_pager_first',
 798                         'prev' => 'table_pager_prev',
 799                         'next' => 'table_pager_next',
 800                         'last' => 'table_pager_last',
 801                 );
 802                 $images = array(
 803                         'first' => $wgContLang->isRTL() ? 'arrow_last_25.png' : 'arrow_first_25.png',
 804                         'prev' =>  $wgContLang->isRTL() ? 'arrow_right_25.png' : 'arrow_left_25.png',
 805                         'next' =>  $wgContLang->isRTL() ? 'arrow_left_25.png' : 'arrow_right_25.png',
 806                         'last' =>  $wgContLang->isRTL() ? 'arrow_first_25.png' : 'arrow_last_25.png',
 807                 );
 808                 $disabledImages = array(
 809                         'first' => $wgContLang->isRTL() ? 'arrow_disabled_last_25.png' : 'arrow_disabled_first_25.png',
 810                         'prev' =>  $wgContLang->isRTL() ? 'arrow_disabled_right_25.png' : 'arrow_disabled_left_25.png',
 811                         'next' =>  $wgContLang->isRTL() ? 'arrow_disabled_left_25.png' : 'arrow_disabled_right_25.png',
 812                         'last' =>  $wgContLang->isRTL() ? 'arrow_disabled_first_25.png' : 'arrow_disabled_last_25.png',
 813                 );
 814
 815                 $linkTexts = array();
 816                 $disabledTexts = array();
 817                 foreach ( $labels as $type => $label ) {
 818                         $msgLabel = wfMsgHtml( $label );
 819                         $linkTexts[$type] = "<img src=\"$path/{$images[$type]}\" alt=\"$msgLabel\"/><br/>$msgLabel";
 820                         $disabledTexts[$type] = "<img src=\"$path/{$disabledImages[$type]}\" alt=\"$msgLabel\"/><br/>$msgLabel";
 821                 }
 822                 $links = $this->getPagingLinks( $linkTexts, $disabledTexts );
 823
 824                 $navClass = htmlspecialchars( $this->getNavClass() );
 825                 $s = "<table class=\"$navClass\" align=\"center\" cellpadding=\"3\"><tr>\n";
 826                 $cellAttrs = 'valign="top" align="center" width="' . 100 / count( $links ) . '%"';
 827                 foreach ( $labels as $type => $label ) {
 828                         $s .= "<td $cellAttrs>{$links[$type]}</td>\n";
 829                 }
 830                 $s .= "</tr></table>\n";
 831                 return $s;
 832         }
 833
 834         /**
 835          * Get a <select> element which has options for each of the allowed limits
 836          */
 837         function getLimitSelect() {
 838                 global $wgLang;
 839                 $s = "<select name=\"limit\">";
 840                 foreach ( $this->mLimitsShown as $limit ) {
 841                         $selected = $limit == $this->mLimit ? 'selected="selected"' : '';
 842                         $formattedLimit = $wgLang->formatNum( $limit );
 843                         $s .= "<option value=\"$limit\" $selected>$formattedLimit</option>\n";
 844                 }
 845                 $s .= "</select>";
 846                 return $s;
 847         }
 848
 849         /**
 850          * Get <input type="hidden"> elements for use in a method="get" form.
 851          * Resubmits all defined elements of the $_GET array, except for a
 852          * blacklist, passed in the $blacklist parameter.
 853          */
 854         function getHiddenFields( $blacklist = array() ) {
 855                 $blacklist = (array)$blacklist;
 856                 $query = $_GET;
 857                 foreach ( $blacklist as $name ) {
 858                         unset( $query[$name] );
 859                 }
 860                 $s = '';
 861                 foreach ( $query as $name => $value ) {
 862                         $encName = htmlspecialchars( $name );
 863                         $encValue = htmlspecialchars( $value );
 864                         $s .= "<input type=\"hidden\" name=\"$encName\" value=\"$encValue\"/>\n";
 865                 }
 866                 return $s;
 867         }
 868
 869         /**
 870          * Get a form containing a limit selection dropdown
 871          */
 872         function getLimitForm() {
 873                 # Make the select with some explanatory text
 874                 $url = $this->getTitle()->escapeLocalURL();
 875                 $msgSubmit = wfMsgHtml( 'table_pager_limit_submit' );
 876                 return
 877                         "<form method=\"get\" action=\"$url\">" .
 878                         wfMsgHtml( 'table_pager_limit', $this->getLimitSelect() ) .
 879                         "\n<input type=\"submit\" value=\"$msgSubmit\"/>\n" .
 880                         $this->getHiddenFields( array('limit','title') ) .
 881                         "</form>\n";
 882         }
 883
 884         /**
 885          * Return true if the named field should be sortable by the UI, false
 886          * otherwise
 887          *
 888          * @param string $field
 889          */
 890         abstract function isFieldSortable( $field );
 891
 892         /**
 893          * Format a table cell. The return value should be HTML, but use an empty
 894          * string not &nbsp; for empty cells. Do not include the <td> and </td>.
 895          *
 896          * The current result row is available as $this->mCurrentRow, in case you
 897          * need more context.
 898          *
 899          * @param string $name The database field name
 900          * @param string $value The value retrieved from the database
 901          */
 902         abstract function formatValue( $name, $value );
 903
 904         /**
 905          * The database field name used as a default sort order
 906          */
 907         abstract function getDefaultSort();
 908
 909         /**
 910          * An array mapping database field names to a textual description of the
 911          * field name, for use in the table header. The description should be plain
 912          * text, it will be HTML-escaped later.
 913          */
 914         abstract function getFieldNames();
 915 }