includes/Pager.php

   1 <?php
   2
   3 /**
   4  * Basic pager interface.
   5  * @addtogroup Pager
   6  */
   7 interface Pager {
   8         function getNavigationBar();
   9         function getBody();
  10 }
  11
  12 /**
  13  * IndexPager is an efficient pager which uses a (roughly unique) index in the
  14  * data set to implement paging, rather than a "LIMIT offset,limit" clause.
  15  * In MySQL, such a limit/offset clause requires counting through the
  16  * specified number of offset rows to find the desired data, which can be
  17  * expensive for large offsets.
  18  *
  19  * ReverseChronologicalPager is a child class of the abstract IndexPager, and
  20  * contains  some formatting and display code which is specific to the use of
  21  * timestamps as  indexes. Here is a synopsis of its operation:
  22  *
  23  *    * The query is specified by the offset, limit and direction (dir)
  24  *      parameters, in addition to any subclass-specific parameters.
  25  *    * The offset is the non-inclusive start of the DB query. A row with an
  26  *      index value equal to the offset will never be shown.
  27  *    * The query may either be done backwards, where the rows are returned by
  28  *      the database in the opposite order to which they are displayed to the
  29  *      user, or forwards. This is specified by the "dir" parameter, dir=prev
  30  *      means backwards, anything else means forwards. The offset value
  31  *      specifies the start of the database result set, which may be either
  32  *      the start or end of the displayed data set. This allows "previous"
  33  *      links to be implemented without knowledge of the index value at the
  34  *      start of the previous page.
  35  *    * An additional row beyond the user-specified limit is always requested.
  36  *      This allows us to tell whether we should display a "next" link in the
  37  *      case of forwards mode, or a "previous" link in the case of backwards
  38  *      mode. Determining whether to display the other link (the one for the
  39  *      page before the start of the database result set) can be done
  40  *      heuristically by examining the offset.
  41  *
  42  *    * An empty offset indicates that the offset condition should be omitted
  43  *      from the query. This naturally produces either the first page or the
  44  *      last page depending on the dir parameter.
  45  *
  46  *  Subclassing the pager to implement concrete functionality should be fairly
  47  *  simple, please see the examples in PageHistory.php and
  48  *  SpecialIpblocklist.php. You just need to override formatRow(),
  49  *  getQueryInfo() and getIndexField(). Don't forget to call the parent
  50  *  constructor if you override it.
  51  *
  52  * @addtogroup Pager
  53  */
  54 abstract class IndexPager implements Pager {
  55         public $mRequest;
  56         public $mLimitsShown = array( 20, 50, 100, 250, 500 );
  57         public $mDefaultLimit = 50;
  58         public $mOffset, $mLimit;
  59         public $mQueryDone = false;
  60         public $mDb;
  61         public $mPastTheEndRow;
  62
  63         protected $mIndexField;
  64
  65         /**
  66          * Default query direction. false for ascending, true for descending
  67          */
  68         public $mDefaultDirection = false;
  69
  70         /**
  71          * Result object for the query. Warning: seek before use.
  72          */
  73         public $mResult;
  74
  75         function __construct() {
  76                 global $wgRequest, $wgUser;
  77                 $this->mRequest = $wgRequest;
  78
  79                 # NB: the offset is quoted, not validated. It is treated as an
  80                 # arbitrary string to support the widest variety of index types. Be
  81                 # careful outputting it into HTML!
  82                 $this->mOffset = $this->mRequest->getText( 'offset' );
  83
  84                 # Use consistent behavior for the limit options
  85                 $this->mDefaultLimit = intval( $wgUser->getOption( 'rclimit' ) );
  86                 list( $this->mLimit, /* $offset */ ) = $this->mRequest->getLimitOffset();
  87
  88                 $this->mIsBackwards = ( $this->mRequest->getVal( 'dir' ) == 'prev' );
  89                 $this->mIndexField = $this->getIndexField();
  90                 $this->mDb = wfGetDB( DB_SLAVE );
  91         }
  92
  93         /**
  94          * Do the query, using information from the object context. This function
  95          * has been kept minimal to make it overridable if necessary, to allow for
  96          * result sets formed from multiple DB queries.
  97          */
  98         function doQuery() {
  99                 # Use the child class name for profiling
 100                 $fname = __METHOD__ . ' (' . get_class( $this ) . ')';
 101                 wfProfileIn( $fname );
 102
 103                 $descending = ( $this->mIsBackwards == $this->mDefaultDirection );
 104                 # Plus an extra row so that we can tell the "next" link should be shown
 105                 $queryLimit = $this->mLimit + 1;
 106
 107                 $this->mResult = $this->reallyDoQuery( $this->mOffset, $queryLimit, $descending );
 108                 $this->extractResultInfo( $this->mOffset, $queryLimit, $this->mResult );
 109                 $this->mQueryDone = true;
 110
 111                 $this->preprocessResults( $this->mResult );
 112                 $this->mResult->rewind(); // Paranoia
 113
 114                 wfProfileOut( $fname );
 115         }
 116
 117         /**
 118          * Extract some useful data from the result object for use by
 119          * the navigation bar, put it into $this
 120          */
 121         function extractResultInfo( $offset, $limit, ResultWrapper $res ) {
 122                 $numRows = $res->numRows();
 123                 if ( $numRows ) {
 124                         $row = $res->fetchRow();
 125                         $firstIndex = $row[$this->mIndexField];
 126
 127                         # Discard the extra result row if there is one
 128                         if ( $numRows > $this->mLimit && $numRows > 1 ) {
 129                                 $res->seek( $numRows - 1 );
 130                                 $this->mPastTheEndRow = $res->fetchObject();
 131                                 $indexField = $this->mIndexField;
 132                                 $this->mPastTheEndIndex = $this->mPastTheEndRow->$indexField;
 133                                 $res->seek( $numRows - 2 );
 134                                 $row = $res->fetchRow();
 135                                 $lastIndex = $row[$this->mIndexField];
 136                         } else {
 137                                 $this->mPastTheEndRow = null;
 138                                 # Setting indexes to an empty string means that they will be
 139                                 # omitted if they would otherwise appear in URLs. It just so
 140                                 # happens that this  is the right thing to do in the standard
 141                                 # UI, in all the relevant cases.
 142                                 $this->mPastTheEndIndex = '';
 143                                 $res->seek( $numRows - 1 );
 144                                 $row = $res->fetchRow();
 145                                 $lastIndex = $row[$this->mIndexField];
 146                         }
 147                 } else {
 148                         $firstIndex = '';
 149                         $lastIndex = '';
 150                         $this->mPastTheEndRow = null;
 151                         $this->mPastTheEndIndex = '';
 152                 }
 153
 154                 if ( $this->mIsBackwards ) {
 155                         $this->mIsFirst = ( $numRows < $limit );
 156                         $this->mIsLast = ( $offset == '' );
 157                         $this->mLastShown = $firstIndex;
 158                         $this->mFirstShown = $lastIndex;
 159                 } else {
 160                         $this->mIsFirst = ( $offset == '' );
 161                         $this->mIsLast = ( $numRows < $limit );
 162                         $this->mLastShown = $lastIndex;
 163                         $this->mFirstShown = $firstIndex;
 164                 }
 165         }
 166
 167         /**
 168          * Do a query with specified parameters, rather than using the object
 169          * context
 170          *
 171          * @param string $offset Index offset, inclusive
 172          * @param integer $limit Exact query limit
 173          * @param boolean $descending Query direction, false for ascending, true for descending
 174          * @return ResultWrapper
 175          */
 176         function reallyDoQuery( $offset, $limit, $descending ) {
 177                 $fname = __METHOD__ . ' (' . get_class( $this ) . ')';
 178                 $info = $this->getQueryInfo();
 179                 $tables = $info['tables'];
 180                 $fields = $info['fields'];
 181                 $conds = isset( $info['conds'] ) ? $info['conds'] : array();
 182                 $options = isset( $info['options'] ) ? $info['options'] : array();
 183                 if ( $descending ) {
 184                         $options['ORDER BY'] = $this->mIndexField;
 185                         $operator = '>';
 186                 } else {
 187                         $options['ORDER BY'] = $this->mIndexField . ' DESC';
 188                         $operator = '<';
 189                 }
 190                 if ( $offset != '' ) {
 191                         $conds[] = $this->mIndexField . $operator . $this->mDb->addQuotes( $offset );
 192                 }
 193                 $options['LIMIT'] = intval( $limit );
 194                 $res = $this->mDb->select( $tables, $fields, $conds, $fname, $options );
 195                 return new ResultWrapper( $this->mDb, $res );
 196         }
 197
 198         /**
 199          * Pre-process results; useful for performing batch existence checks, etc.
 200          *
 201          * @param ResultWrapper $result Result wrapper
 202          */
 203         protected function preprocessResults( $result ) {}
 204
 205         /**
 206          * Get the formatted result list. Calls getStartBody(), formatRow() and
 207          * getEndBody(), concatenates the results and returns them.
 208          */
 209         function getBody() {
 210                 if ( !$this->mQueryDone ) {
 211                         $this->doQuery();
 212                 }
 213                 # Don't use any extra rows returned by the query
 214                 $numRows = min( $this->mResult->numRows(), $this->mLimit );
 215
 216                 $s = $this->getStartBody();
 217                 if ( $numRows ) {
 218                         if ( $this->mIsBackwards ) {
 219                                 for ( $i = $numRows - 1; $i >= 0; $i-- ) {
 220                                         $this->mResult->seek( $i );
 221                                         $row = $this->mResult->fetchObject();
 222                                         $s .= $this->formatRow( $row );
 223                                 }
 224                         } else {
 225                                 $this->mResult->seek( 0 );
 226                                 for ( $i = 0; $i < $numRows; $i++ ) {
 227                                         $row = $this->mResult->fetchObject();
 228                                         $s .= $this->formatRow( $row );
 229                                 }
 230                         }
 231                 } else {
 232                         $s .= $this->getEmptyBody();
 233                 }
 234                 $s .= $this->getEndBody();
 235                 return $s;
 236         }
 237
 238         /**
 239          * Make a self-link
 240          */
 241         function makeLink($text, $query = null) {
 242                 if ( $query === null ) {
 243                         return $text;
 244                 }
 245                 return $this->getSkin()->makeKnownLinkObj( $this->getTitle(), $text,
 246                                 wfArrayToCGI( $query, $this->getDefaultQuery() ) );
 247         }
 248
 249         /**
 250          * Hook into getBody(), allows text to be inserted at the start. This
 251          * will be called even if there are no rows in the result set.
 252          */
 253         function getStartBody() {
 254                 return '';
 255         }
 256
 257         /**
 258          * Hook into getBody() for the end of the list
 259          */
 260         function getEndBody() {
 261                 return '';
 262         }
 263
 264         /**
 265          * Hook into getBody(), for the bit between the start and the
 266          * end when there are no rows
 267          */
 268         function getEmptyBody() {
 269                 return '';
 270         }
 271
 272         /**
 273          * Title used for self-links. Override this if you want to be able to
 274          * use a title other than $wgTitle
 275          */
 276         function getTitle() {
 277                 return $GLOBALS['wgTitle'];
 278         }
 279
 280         /**
 281          * Get the current skin. This can be overridden if necessary.
 282          */
 283         function getSkin() {
 284                 if ( !isset( $this->mSkin ) ) {
 285                         global $wgUser;
 286                         $this->mSkin = $wgUser->getSkin();
 287                 }
 288                 return $this->mSkin;
 289         }
 290
 291         /**
 292          * Get an array of query parameters that should be put into self-links.
 293          * By default, all parameters passed in the URL are used, except for a
 294          * short blacklist.
 295          */
 296         function getDefaultQuery() {
 297                 if ( !isset( $this->mDefaultQuery ) ) {
 298                         $this->mDefaultQuery = $_GET;
 299                         unset( $this->mDefaultQuery['title'] );
 300                         unset( $this->mDefaultQuery['dir'] );
 301                         unset( $this->mDefaultQuery['offset'] );
 302                         unset( $this->mDefaultQuery['limit'] );
 303                 }
 304                 return $this->mDefaultQuery;
 305         }
 306
 307         /**
 308          * Get the number of rows in the result set
 309          */
 310         function getNumRows() {
 311                 if ( !$this->mQueryDone ) {
 312                         $this->doQuery();
 313                 }
 314                 return $this->mResult->numRows();
 315         }
 316
 317         /**
 318          * Get a query array for the prev, next, first and last links.
 319          */
 320         function getPagingQueries() {
 321                 if ( !$this->mQueryDone ) {
 322                         $this->doQuery();
 323                 }
 324
 325                 # Don't announce the limit everywhere if it's the default
 326                 $urlLimit = $this->mLimit == $this->mDefaultLimit ? '' : $this->mLimit;
 327
 328                 if ( $this->mIsFirst ) {
 329                         $prev = false;
 330                         $first = false;
 331                 } else {
 332                         $prev = array( 'dir' => 'prev', 'offset' => $this->mFirstShown, 'limit' => $urlLimit );
 333                         $first = array( 'limit' => $urlLimit );
 334                 }
 335                 if ( $this->mIsLast ) {
 336                         $next = false;
 337                         $last = false;
 338                 } else {
 339                         $next = array( 'offset' => $this->mLastShown, 'limit' => $urlLimit );
 340                         $last = array( 'dir' => 'prev', 'limit' => $urlLimit );
 341                 }
 342                 return array( 'prev' => $prev, 'next' => $next, 'first' => $first, 'last' => $last );
 343         }
 344
 345         /**
 346          * Get paging links. If a link is disabled, the item from $disabledTexts
 347          * will be used. If there is no such item, the unlinked text from
 348          * $linkTexts will be used. Both $linkTexts and $disabledTexts are arrays
 349          * of HTML.
 350          */
 351         function getPagingLinks( $linkTexts, $disabledTexts = array() ) {
 352                 $queries = $this->getPagingQueries();
 353                 $links = array();
 354                 foreach ( $queries as $type => $query ) {
 355                         if ( $query !== false ) {
 356                                 $links[$type] = $this->makeLink( $linkTexts[$type], $queries[$type] );
 357                         } elseif ( isset( $disabledTexts[$type] ) ) {
 358                                 $links[$type] = $disabledTexts[$type];
 359                         } else {
 360                                 $links[$type] = $linkTexts[$type];
 361                         }
 362                 }
 363                 return $links;
 364         }
 365
 366         function getLimitLinks() {
 367                 global $wgLang;
 368                 $links = array();
 369                 if ( $this->mIsBackwards ) {
 370                         $offset = $this->mPastTheEndIndex;
 371                 } else {
 372                         $offset = $this->mOffset;
 373                 }
 374                 foreach ( $this->mLimitsShown as $limit ) {
 375                         $links[] = $this->makeLink( $wgLang->formatNum( $limit ),
 376                                 array( 'offset' => $offset, 'limit' => $limit ) );
 377                 }
 378                 return $links;
 379         }
 380
 381         /**
 382          * Abstract formatting function. This should return an HTML string
 383          * representing the result row $row. Rows will be concatenated and
 384          * returned by getBody()
 385          */
 386         abstract function formatRow( $row );
 387
 388         /**
 389          * This function should be overridden to provide all parameters
 390          * needed for the main paged query. It returns an associative
 391          * array with the following elements:
 392          *    tables => Table(s) for passing to Database::select()
 393          *    fields => Field(s) for passing to Database::select(), may be *
 394          *    conds => WHERE conditions
 395          *    options => option array
 396          */
 397         abstract function getQueryInfo();
 398
 399         /**
 400          * This function should be overridden to return the name of the
 401          * index field.
 402          */
 403         abstract function getIndexField();
 404 }
 405
 406
 407 /**
 408  * IndexPager with an alphabetic list and a formatted navigation bar
 409  * @addtogroup Pager
 410  */
 411 abstract class AlphabeticPager extends IndexPager {
 412         public $mDefaultDirection = false;
 413
 414         function __construct() {
 415                 parent::__construct();
 416         }
 417
 418         /**
 419          * Shamelessly stolen bits from ReverseChronologicalPager, d
 420          * didn't want to do class magic as may be still revamped
 421          */
 422         function getNavigationBar() {
 423                 global $wgLang;
 424
 425                 $linkTexts = array(
 426                         'prev' => wfMsgHtml( 'prevn', $wgLang->formatNum( $this->mLimit ) ),
 427                         'next' => wfMsgHtml( 'nextn', $wgLang->formatNum($this->mLimit ) ),
 428                         'first' => wfMsgHtml( 'page_first' ), /* Introduced the message */
 429                         'last' => wfMsgHtml( 'page_last' )  /* Introduced the message */
 430                 );
 431
 432                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 433                 $limitLinks = $this->getLimitLinks();
 434                 $limits = implode( ' | ', $limitLinks );
 435
 436                 $this->mNavigationBar = "({$pagingLinks['first']} | {$pagingLinks['last']}) " . wfMsgHtml("viewprevnext", $pagingLinks['prev'], $pagingLinks['next'], $limits);
 437                 return $this->mNavigationBar;
 438
 439         }
 440 }
 441
 442 /**
 443  * IndexPager with a formatted navigation bar
 444  * @addtogroup Pager
 445  */
 446 abstract class ReverseChronologicalPager extends IndexPager {
 447         public $mDefaultDirection = true;
 448
 449         function __construct() {
 450                 parent::__construct();
 451         }
 452
 453         function getNavigationBar() {
 454                 global $wgLang;
 455
 456                 if ( isset( $this->mNavigationBar ) ) {
 457                         return $this->mNavigationBar;
 458                 }
 459                 $nicenumber = $wgLang->formatNum( $this->mLimit );
 460                 $linkTexts = array(
 461                         'prev' => wfMsgExt( 'pager-newer-n', array( 'parsemag' ), $nicenumber ),
 462                         'next' => wfMsgExt( 'pager-older-n', array( 'parsemag' ), $nicenumber ),
 463                         'first' => wfMsgHtml( 'histlast' ),
 464                         'last' => wfMsgHtml( 'histfirst' )
 465                 );
 466
 467                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 468                 $limitLinks = $this->getLimitLinks();
 469                 $limits = implode( ' | ', $limitLinks );
 470
 471                 $this->mNavigationBar = "({$pagingLinks['first']} | {$pagingLinks['last']}) " .
 472                         wfMsgHtml("viewprevnext", $pagingLinks['prev'], $pagingLinks['next'], $limits);
 473                 return $this->mNavigationBar;
 474         }
 475 }
 476
 477 /**
 478  * Table-based display with a user-selectable sort order
 479  * @addtogroup Pager
 480  */
 481 abstract class TablePager extends IndexPager {
 482         var $mSort;
 483         var $mCurrentRow;
 484
 485         function __construct() {
 486                 global $wgRequest;
 487                 $this->mSort = $wgRequest->getText( 'sort' );
 488                 if ( !array_key_exists( $this->mSort, $this->getFieldNames() ) ) {
 489                         $this->mSort = $this->getDefaultSort();
 490                 }
 491                 if ( $wgRequest->getBool( 'asc' ) ) {
 492                         $this->mDefaultDirection = false;
 493                 } elseif ( $wgRequest->getBool( 'desc' ) ) {
 494                         $this->mDefaultDirection = true;
 495                 } /* Else leave it at whatever the class default is */
 496
 497                 parent::__construct();
 498         }
 499
 500         function getStartBody() {
 501                 global $wgStylePath;
 502                 $tableClass = htmlspecialchars( $this->getTableClass() );
 503                 $sortClass = htmlspecialchars( $this->getSortHeaderClass() );
 504
 505                 $s = "<table border='1' class=\"$tableClass\"><thead><tr>\n";
 506                 $fields = $this->getFieldNames();
 507
 508                 # Make table header
 509                 foreach ( $fields as $field => $name ) {
 510                         if ( strval( $name ) == '' ) {
 511                                 $s .= "<th>&nbsp;</th>\n";
 512                         } elseif ( $this->isFieldSortable( $field ) ) {
 513                                 $query = array( 'sort' => $field, 'limit' => $this->mLimit );
 514                                 if ( $field == $this->mSort ) {
 515                                         # This is the sorted column
 516                                         # Prepare a link that goes in the other sort order
 517                                         if ( $this->mDefaultDirection ) {
 518                                                 # Descending
 519                                                 $image = 'Arr_u.png';
 520                                                 $query['asc'] = '1';
 521                                                 $query['desc'] = '';
 522                                                 $alt = htmlspecialchars( wfMsg( 'descending_abbrev' ) );
 523                                         } else {
 524                                                 # Ascending
 525                                                 $image = 'Arr_d.png';
 526                                                 $query['asc'] = '';
 527                                                 $query['desc'] = '1';
 528                                                 $alt = htmlspecialchars( wfMsg( 'ascending_abbrev' ) );
 529                                         }
 530                                         $image = htmlspecialchars( "$wgStylePath/common/images/$image" );
 531                                         $link = $this->makeLink(
 532                                                 "<img width=\"12\" height=\"12\" alt=\"$alt\" src=\"$image\" />" .
 533                                                 htmlspecialchars( $name ), $query );
 534                                         $s .= "<th class=\"$sortClass\">$link</th>\n";
 535                                 } else {
 536                                         $s .= '<th>' . $this->makeLink( htmlspecialchars( $name ), $query ) . "</th>\n";
 537                                 }
 538                         } else {
 539                                 $s .= '<th>' . htmlspecialchars( $name ) . "</th>\n";
 540                         }
 541                 }
 542                 $s .= "</tr></thead><tbody>\n";
 543                 return $s;
 544         }
 545
 546         function getEndBody() {
 547                 return "</tbody></table>\n";
 548         }
 549
 550         function getEmptyBody() {
 551                 $colspan = count( $this->getFieldNames() );
 552                 $msgEmpty = wfMsgHtml( 'table_pager_empty' );
 553                 return "<tr><td colspan=\"$colspan\">$msgEmpty</td></tr>\n";
 554         }
 555
 556         function formatRow( $row ) {
 557                 $s = "<tr>\n";
 558                 $fieldNames = $this->getFieldNames();
 559                 $this->mCurrentRow = $row;  # In case formatValue needs to know
 560                 foreach ( $fieldNames as $field => $name ) {
 561                         $value = isset( $row->$field ) ? $row->$field : null;
 562                         $formatted = strval( $this->formatValue( $field, $value ) );
 563                         if ( $formatted == '' ) {
 564                                 $formatted = '&nbsp;';
 565                         }
 566                         $class = 'TablePager_col_' . htmlspecialchars( $field );
 567                         $s .= "<td class=\"$class\">$formatted</td>\n";
 568                 }
 569                 $s .= "</tr>\n";
 570                 return $s;
 571         }
 572
 573         function getIndexField() {
 574                 return $this->mSort;
 575         }
 576
 577         function getTableClass() {
 578                 return 'TablePager';
 579         }
 580
 581         function getNavClass() {
 582                 return 'TablePager_nav';
 583         }
 584
 585         function getSortHeaderClass() {
 586                 return 'TablePager_sort';
 587         }
 588
 589         /**
 590          * A navigation bar with images
 591          */
 592         function getNavigationBar() {
 593                 global $wgStylePath, $wgContLang;
 594                 $path = "$wgStylePath/common/images";
 595                 $labels = array(
 596                         'first' => 'table_pager_first',
 597                         'prev' => 'table_pager_prev',
 598                         'next' => 'table_pager_next',
 599                         'last' => 'table_pager_last',
 600                 );
 601                 $images = array(
 602                         'first' => $wgContLang->isRTL() ? 'arrow_last_25.png' : 'arrow_first_25.png',
 603                         'prev' =>  $wgContLang->isRTL() ? 'arrow_right_25.png' : 'arrow_left_25.png',
 604                         'next' =>  $wgContLang->isRTL() ? 'arrow_left_25.png' : 'arrow_right_25.png',
 605                         'last' =>  $wgContLang->isRTL() ? 'arrow_first_25.png' : 'arrow_last_25.png',
 606                 );
 607                 $disabledImages = array(
 608                         'first' => $wgContLang->isRTL() ? 'arrow_disabled_last_25.png' : 'arrow_disabled_first_25.png',
 609                         'prev' =>  $wgContLang->isRTL() ? 'arrow_disabled_right_25.png' : 'arrow_disabled_left_25.png',
 610                         'next' =>  $wgContLang->isRTL() ? 'arrow_disabled_left_25.png' : 'arrow_disabled_right_25.png',
 611                         'last' =>  $wgContLang->isRTL() ? 'arrow_disabled_first_25.png' : 'arrow_disabled_last_25.png',
 612                 );
 613
 614                 $linkTexts = array();
 615                 $disabledTexts = array();
 616                 foreach ( $labels as $type => $label ) {
 617                         $msgLabel = wfMsgHtml( $label );
 618                         $linkTexts[$type] = "<img src=\"$path/{$images[$type]}\" alt=\"$msgLabel\"/><br/>$msgLabel";
 619                         $disabledTexts[$type] = "<img src=\"$path/{$disabledImages[$type]}\" alt=\"$msgLabel\"/><br/>$msgLabel";
 620                 }
 621                 $links = $this->getPagingLinks( $linkTexts, $disabledTexts );
 622
 623                 $navClass = htmlspecialchars( $this->getNavClass() );
 624                 $s = "<table class=\"$navClass\" align=\"center\" cellpadding=\"3\"><tr>\n";
 625                 $cellAttrs = 'valign="top" align="center" width="' . 100 / count( $links ) . '%"';
 626                 foreach ( $labels as $type => $label ) {
 627                         $s .= "<td $cellAttrs>{$links[$type]}</td>\n";
 628                 }
 629                 $s .= "</tr></table>\n";
 630                 return $s;
 631         }
 632
 633         /**
 634          * Get a <select> element which has options for each of the allowed limits
 635          */
 636         function getLimitSelect() {
 637                 global $wgLang;
 638                 $s = "<select name=\"limit\">";
 639                 foreach ( $this->mLimitsShown as $limit ) {
 640                         $selected = $limit == $this->mLimit ? 'selected="selected"' : '';
 641                         $formattedLimit = $wgLang->formatNum( $limit );
 642                         $s .= "<option value=\"$limit\" $selected>$formattedLimit</option>\n";
 643                 }
 644                 $s .= "</select>";
 645                 return $s;
 646         }
 647
 648         /**
 649          * Get <input type="hidden"> elements for use in a method="get" form.
 650          * Resubmits all defined elements of the $_GET array, except for a
 651          * blacklist, passed in the $blacklist parameter.
 652          */
 653         function getHiddenFields( $blacklist = array() ) {
 654                 $blacklist = (array)$blacklist;
 655                 $query = $_GET;
 656                 foreach ( $blacklist as $name ) {
 657                         unset( $query[$name] );
 658                 }
 659                 $s = '';
 660                 foreach ( $query as $name => $value ) {
 661                         $encName = htmlspecialchars( $name );
 662                         $encValue = htmlspecialchars( $value );
 663                         $s .= "<input type=\"hidden\" name=\"$encName\" value=\"$encValue\"/>\n";
 664                 }
 665                 return $s;
 666         }
 667
 668         /**
 669          * Get a form containing a limit selection dropdown
 670          */
 671         function getLimitForm() {
 672                 # Make the select with some explanatory text
 673                 $url = $this->getTitle()->escapeLocalURL();
 674                 $msgSubmit = wfMsgHtml( 'table_pager_limit_submit' );
 675                 return
 676                         "<form method=\"get\" action=\"$url\">" .
 677                         wfMsgHtml( 'table_pager_limit', $this->getLimitSelect() ) .
 678                         "\n<input type=\"submit\" value=\"$msgSubmit\"/>\n" .
 679                         $this->getHiddenFields( 'limit' ) .
 680                         "</form>\n";
 681         }
 682
 683         /**
 684          * Return true if the named field should be sortable by the UI, false
 685          * otherwise
 686          *
 687          * @param string $field
 688          */
 689         abstract function isFieldSortable( $field );
 690
 691         /**
 692          * Format a table cell. The return value should be HTML, but use an empty
 693          * string not &nbsp; for empty cells. Do not include the <td> and </td>.
 694          *
 695          * The current result row is available as $this->mCurrentRow, in case you
 696          * need more context.
 697          *
 698          * @param string $name The database field name
 699          * @param string $value The value retrieved from the database
 700          */
 701         abstract function formatValue( $name, $value );
 702
 703         /**
 704          * The database field name used as a default sort order
 705          */
 706         abstract function getDefaultSort();
 707
 708         /**
 709          * An array mapping database field names to a textual description of the
 710          * field name, for use in the table header. The description should be plain
 711          * text, it will be HTML-escaped later.
 712          */
 713         abstract function getFieldNames();
 714 }