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