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