includes/Pager.php

   1 <?php
   2 /**
   3  * @defgroup Pager Pager
   4  *
   5  * @file
   6  * @ingroup Pager
   7  */
   8
   9 /**
  10  * Basic pager interface.
  11  * @ingroup Pager
  12  */
  13 interface Pager {
  14         function getNavigationBar();
  15         function getBody();
  16 }
  17
  18 /**
  19  * IndexPager is an efficient pager which uses a (roughly unique) index in the
  20  * data set to implement paging, rather than a "LIMIT offset,limit" clause.
  21  * In MySQL, such a limit/offset clause requires counting through the
  22  * specified number of offset rows to find the desired data, which can be
  23  * expensive for large offsets.
  24  *
  25  * ReverseChronologicalPager is a child class of the abstract IndexPager, and
  26  * contains  some formatting and display code which is specific to the use of
  27  * timestamps as  indexes. Here is a synopsis of its operation:
  28  *
  29  *    * The query is specified by the offset, limit and direction (dir)
  30  *      parameters, in addition to any subclass-specific parameters.
  31  *    * The offset is the non-inclusive start of the DB query. A row with an
  32  *      index value equal to the offset will never be shown.
  33  *    * The query may either be done backwards, where the rows are returned by
  34  *      the database in the opposite order to which they are displayed to the
  35  *      user, or forwards. This is specified by the "dir" parameter, dir=prev
  36  *      means backwards, anything else means forwards. The offset value
  37  *      specifies the start of the database result set, which may be either
  38  *      the start or end of the displayed data set. This allows "previous"
  39  *      links to be implemented without knowledge of the index value at the
  40  *      start of the previous page.
  41  *    * An additional row beyond the user-specified limit is always requested.
  42  *      This allows us to tell whether we should display a "next" link in the
  43  *      case of forwards mode, or a "previous" link in the case of backwards
  44  *      mode. Determining whether to display the other link (the one for the
  45  *      page before the start of the database result set) can be done
  46  *      heuristically by examining the offset.
  47  *
  48  *    * An empty offset indicates that the offset condition should be omitted
  49  *      from the query. This naturally produces either the first page or the
  50  *      last page depending on the dir parameter.
  51  *
  52  *  Subclassing the pager to implement concrete functionality should be fairly
  53  *  simple, please see the examples in PageHistory.php and
  54  *  SpecialIpblocklist.php. You just need to override formatRow(),
  55  *  getQueryInfo() and getIndexField(). Don't forget to call the parent
  56  *  constructor if you override it.
  57  *
  58  * @ingroup Pager
  59  */
  60 abstract class IndexPager implements Pager {
  61         public $mRequest;
  62         public $mLimitsShown = array( 20, 50, 100, 250, 500 );
  63         public $mDefaultLimit = 50;
  64         public $mOffset, $mLimit;
  65         public $mQueryDone = false;
  66         public $mDb;
  67         public $mPastTheEndRow;
  68
  69         /**
  70          * The index to actually be used for ordering.  This is a single string e-
  71          * ven if multiple orderings are supported.
  72          */
  73         protected $mIndexField;
  74         /** For pages that support multiple types of ordering, which one to use. */
  75         protected $mOrderType;
  76         /**
  77          * $mDefaultDirection gives the direction to use when sorting results:
  78          * false for ascending, true for descending.  If $mIsBackwards is set, we
  79          * start from the opposite end, but we still sort the page itself according
  80          * to $mDefaultDirection.  E.g., if $mDefaultDirection is false but we're
  81          * going backwards, we'll display the last page of results, but the last
  82          * result will be at the bottom, not the top.
  83          *
  84          * Like $mIndexField, $mDefaultDirection will be a single value even if the
  85          * class supports multiple default directions for different order types.
  86          */
  87         public $mDefaultDirection;
  88         public $mIsBackwards;
  89
  90         /**
  91          * Result object for the query. Warning: seek before use.
  92          */
  93         public $mResult;
  94
  95         public function __construct() {
  96                 global $wgRequest, $wgUser;
  97                 $this->mRequest = $wgRequest;
  98
  99                 # NB: the offset is quoted, not validated. It is treated as an
 100                 # arbitrary string to support the widest variety of index types. Be
 101                 # careful outputting it into HTML!
 102                 $this->mOffset = $this->mRequest->getText( 'offset' );
 103
 104                 # Use consistent behavior for the limit options
 105                 $this->mDefaultLimit = intval( $wgUser->getOption( 'rclimit' ) );
 106                 list( $this->mLimit, /* $offset */ ) = $this->mRequest->getLimitOffset();
 107
 108                 $this->mIsBackwards = ( $this->mRequest->getVal( 'dir' ) == 'prev' );
 109                 $this->mDb = wfGetDB( DB_SLAVE );
 110
 111                 $index = $this->getIndexField();
 112                 $order = $this->mRequest->getVal( 'order' );
 113                 if( is_array( $index ) && isset( $index[$order] ) ) {
 114                         $this->mOrderType = $order;
 115                         $this->mIndexField = $index[$order];
 116                 } elseif( is_array( $index ) ) {
 117                         # First element is the default
 118                         reset( $index );
 119                         list( $this->mOrderType, $this->mIndexField ) = each( $index );
 120                 } else {
 121                         # $index is not an array
 122                         $this->mOrderType = null;
 123                         $this->mIndexField = $index;
 124                 }
 125
 126                 if( !isset( $this->mDefaultDirection ) ) {
 127                         $dir = $this->getDefaultDirections();
 128                         $this->mDefaultDirection = is_array( $dir )
 129                                 ? $dir[$this->mOrderType]
 130                                 : $dir;
 131                 }
 132         }
 133
 134         /**
 135          * Do the query, using information from the object context. This function
 136          * has been kept minimal to make it overridable if necessary, to allow for
 137          * result sets formed from multiple DB queries.
 138          */
 139         function doQuery() {
 140                 # Use the child class name for profiling
 141                 $fname = __METHOD__ . ' (' . get_class( $this ) . ')';
 142                 wfProfileIn( $fname );
 143
 144                 $descending = ( $this->mIsBackwards == $this->mDefaultDirection );
 145                 # Plus an extra row so that we can tell the "next" link should be shown
 146                 $queryLimit = $this->mLimit + 1;
 147
 148                 $this->mResult = $this->reallyDoQuery( $this->mOffset, $queryLimit, $descending );
 149                 $this->extractResultInfo( $this->mOffset, $queryLimit, $this->mResult );
 150                 $this->mQueryDone = true;
 151
 152                 $this->preprocessResults( $this->mResult );
 153                 $this->mResult->rewind(); // Paranoia
 154
 155                 wfProfileOut( $fname );
 156         }
 157
 158         /**
 159          * Return the result wrapper.
 160          */
 161         function getResult() {
 162                 return $this->mResult;
 163         }
 164
 165         /**
 166          * Set the offset from an other source than $wgRequest
 167          */
 168         function setOffset( $offset ) {
 169                 $this->mOffset = $offset;
 170         }
 171         /**
 172          * Set the limit from an other source than $wgRequest
 173          */
 174         function setLimit( $limit ) {
 175                 $this->mLimit = $limit;
 176         }
 177
 178         /**
 179          * Extract some useful data from the result object for use by
 180          * the navigation bar, put it into $this
 181          */
 182         function extractResultInfo( $offset, $limit, ResultWrapper $res ) {
 183                 $numRows = $res->numRows();
 184                 if ( $numRows ) {
 185                         $row = $res->fetchRow();
 186                         $firstIndex = $row[$this->mIndexField];
 187
 188                         # Discard the extra result row if there is one
 189                         if ( $numRows > $this->mLimit && $numRows > 1 ) {
 190                                 $res->seek( $numRows - 1 );
 191                                 $this->mPastTheEndRow = $res->fetchObject();
 192                                 $indexField = $this->mIndexField;
 193                                 $this->mPastTheEndIndex = $this->mPastTheEndRow->$indexField;
 194                                 $res->seek( $numRows - 2 );
 195                                 $row = $res->fetchRow();
 196                                 $lastIndex = $row[$this->mIndexField];
 197                         } else {
 198                                 $this->mPastTheEndRow = null;
 199                                 # Setting indexes to an empty string means that they will be
 200                                 # omitted if they would otherwise appear in URLs. It just so
 201                                 # happens that this  is the right thing to do in the standard
 202                                 # UI, in all the relevant cases.
 203                                 $this->mPastTheEndIndex = '';
 204                                 $res->seek( $numRows - 1 );
 205                                 $row = $res->fetchRow();
 206                                 $lastIndex = $row[$this->mIndexField];
 207                         }
 208                 } else {
 209                         $firstIndex = '';
 210                         $lastIndex = '';
 211                         $this->mPastTheEndRow = null;
 212                         $this->mPastTheEndIndex = '';
 213                 }
 214
 215                 if ( $this->mIsBackwards ) {
 216                         $this->mIsFirst = ( $numRows < $limit );
 217                         $this->mIsLast = ( $offset == '' );
 218                         $this->mLastShown = $firstIndex;
 219                         $this->mFirstShown = $lastIndex;
 220                 } else {
 221                         $this->mIsFirst = ( $offset == '' );
 222                         $this->mIsLast = ( $numRows < $limit );
 223                         $this->mLastShown = $lastIndex;
 224                         $this->mFirstShown = $firstIndex;
 225                 }
 226         }
 227
 228         /**
 229          * Do a query with specified parameters, rather than using the object
 230          * context
 231          *
 232          * @param string $offset Index offset, inclusive
 233          * @param integer $limit Exact query limit
 234          * @param boolean $descending Query direction, false for ascending, true for descending
 235          * @return ResultWrapper
 236          */
 237         function reallyDoQuery( $offset, $limit, $descending ) {
 238                 $fname = __METHOD__ . ' (' . get_class( $this ) . ')';
 239                 $info = $this->getQueryInfo();
 240                 $tables = $info['tables'];
 241                 $fields = $info['fields'];
 242                 $conds = isset( $info['conds'] ) ? $info['conds'] : array();
 243                 $options = isset( $info['options'] ) ? $info['options'] : array();
 244                 $join_conds = isset( $info['join_conds'] ) ? $info['join_conds'] : array();
 245                 if ( $descending ) {
 246                         $options['ORDER BY'] = $this->mIndexField;
 247                         $operator = '>';
 248                 } else {
 249                         $options['ORDER BY'] = $this->mIndexField . ' DESC';
 250                         $operator = '<';
 251                 }
 252                 if ( $offset != '' ) {
 253                         $conds[] = $this->mIndexField . $operator . $this->mDb->addQuotes( $offset );
 254                 }
 255                 $options['LIMIT'] = intval( $limit );
 256                 $res = $this->mDb->select( $tables, $fields, $conds, $fname, $options, $join_conds );
 257                 return new ResultWrapper( $this->mDb, $res );
 258         }
 259
 260         /**
 261          * Pre-process results; useful for performing batch existence checks, etc.
 262          *
 263          * @param ResultWrapper $result Result wrapper
 264          */
 265         protected function preprocessResults( $result ) {}
 266
 267         /**
 268          * Get the formatted result list. Calls getStartBody(), formatRow() and
 269          * getEndBody(), concatenates the results and returns them.
 270          */
 271         function getBody() {
 272                 if ( !$this->mQueryDone ) {
 273                         $this->doQuery();
 274                 }
 275                 # Don't use any extra rows returned by the query
 276                 $numRows = min( $this->mResult->numRows(), $this->mLimit );
 277
 278                 $s = $this->getStartBody();
 279                 if ( $numRows ) {
 280                         if ( $this->mIsBackwards ) {
 281                                 for ( $i = $numRows - 1; $i >= 0; $i-- ) {
 282                                         $this->mResult->seek( $i );
 283                                         $row = $this->mResult->fetchObject();
 284                                         $s .= $this->formatRow( $row );
 285                                 }
 286                         } else {
 287                                 $this->mResult->seek( 0 );
 288                                 for ( $i = 0; $i < $numRows; $i++ ) {
 289                                         $row = $this->mResult->fetchObject();
 290                                         $s .= $this->formatRow( $row );
 291                                 }
 292                         }
 293                 } else {
 294                         $s .= $this->getEmptyBody();
 295                 }
 296                 $s .= $this->getEndBody();
 297                 return $s;
 298         }
 299
 300         /**
 301          * Make a self-link
 302          */
 303         function makeLink($text, $query = null, $type=null) {
 304                 if ( $query === null ) {
 305                         return $text;
 306                 }
 307
 308                 $attrs = array();
 309                 if( in_array( $type, array( 'first', 'prev', 'next', 'last' ) ) ) {
 310                         # HTML5 rel attributes
 311                         $attrs['rel'] = $type;
 312                 }
 313
 314                 if( $type ) {
 315                         $attrs['class'] = "mw-{$type}link";
 316                 }
 317                 return $this->getSkin()->link( $this->getTitle(), $text,
 318                         $attrs, $query + $this->getDefaultQuery(), array('noclasses','known') );
 319         }
 320
 321         /**
 322          * Hook into getBody(), allows text to be inserted at the start. This
 323          * will be called even if there are no rows in the result set.
 324          */
 325         function getStartBody() {
 326                 return '';
 327         }
 328
 329         /**
 330          * Hook into getBody() for the end of the list
 331          */
 332         function getEndBody() {
 333                 return '';
 334         }
 335
 336         /**
 337          * Hook into getBody(), for the bit between the start and the
 338          * end when there are no rows
 339          */
 340         function getEmptyBody() {
 341                 return '';
 342         }
 343
 344         /**
 345          * Title used for self-links. Override this if you want to be able to
 346          * use a title other than $wgTitle
 347          */
 348         function getTitle() {
 349                 return $GLOBALS['wgTitle'];
 350         }
 351
 352         /**
 353          * Get the current skin. This can be overridden if necessary.
 354          */
 355         function getSkin() {
 356                 if ( !isset( $this->mSkin ) ) {
 357                         global $wgUser;
 358                         $this->mSkin = $wgUser->getSkin();
 359                 }
 360                 return $this->mSkin;
 361         }
 362
 363         /**
 364          * Get an array of query parameters that should be put into self-links.
 365          * By default, all parameters passed in the URL are used, except for a
 366          * short blacklist.
 367          */
 368         function getDefaultQuery() {
 369                 if ( !isset( $this->mDefaultQuery ) ) {
 370                         $this->mDefaultQuery = $_GET;
 371                         unset( $this->mDefaultQuery['title'] );
 372                         unset( $this->mDefaultQuery['dir'] );
 373                         unset( $this->mDefaultQuery['offset'] );
 374                         unset( $this->mDefaultQuery['limit'] );
 375                         unset( $this->mDefaultQuery['order'] );
 376                         unset( $this->mDefaultQuery['month'] );
 377                         unset( $this->mDefaultQuery['year'] );
 378                 }
 379                 return $this->mDefaultQuery;
 380         }
 381
 382         /**
 383          * Get the number of rows in the result set
 384          */
 385         function getNumRows() {
 386                 if ( !$this->mQueryDone ) {
 387                         $this->doQuery();
 388                 }
 389                 return $this->mResult->numRows();
 390         }
 391
 392         /**
 393          * Get a URL query array for the prev, next, first and last links.
 394          */
 395         function getPagingQueries() {
 396                 if ( !$this->mQueryDone ) {
 397                         $this->doQuery();
 398                 }
 399
 400                 # Don't announce the limit everywhere if it's the default
 401                 $urlLimit = $this->mLimit == $this->mDefaultLimit ? '' : $this->mLimit;
 402
 403                 if ( $this->mIsFirst ) {
 404                         $prev = false;
 405                         $first = false;
 406                 } else {
 407                         $prev = array( 'dir' => 'prev', 'offset' => $this->mFirstShown, 'limit' => $urlLimit );
 408                         $first = array( 'limit' => $urlLimit );
 409                 }
 410                 if ( $this->mIsLast ) {
 411                         $next = false;
 412                         $last = false;
 413                 } else {
 414                         $next = array( 'offset' => $this->mLastShown, 'limit' => $urlLimit );
 415                         $last = array( 'dir' => 'prev', 'limit' => $urlLimit );
 416                 }
 417                 return array( 'prev' => $prev, 'next' => $next, 'first' => $first, 'last' => $last );
 418         }
 419
 420         function isNavigationBarShown() {
 421                 if ( !$this->mQueryDone ) {
 422                         $this->doQuery();
 423                 }
 424                 // Hide navigation by default if there is nothing to page
 425                 return !($this->mIsFirst && $this->mIsLast);
 426         }
 427
 428         /**
 429          * Get paging links. If a link is disabled, the item from $disabledTexts
 430          * will be used. If there is no such item, the unlinked text from
 431          * $linkTexts will be used. Both $linkTexts and $disabledTexts are arrays
 432          * of HTML.
 433          */
 434         function getPagingLinks( $linkTexts, $disabledTexts = array() ) {
 435                 $queries = $this->getPagingQueries();
 436                 $links = array();
 437                 foreach ( $queries as $type => $query ) {
 438                         if ( $query !== false ) {
 439                                 $links[$type] = $this->makeLink( $linkTexts[$type], $queries[$type], $type );
 440                         } elseif ( isset( $disabledTexts[$type] ) ) {
 441                                 $links[$type] = $disabledTexts[$type];
 442                         } else {
 443                                 $links[$type] = $linkTexts[$type];
 444                         }
 445                 }
 446                 return $links;
 447         }
 448
 449         function getLimitLinks() {
 450                 global $wgLang;
 451                 $links = array();
 452                 if ( $this->mIsBackwards ) {
 453                         $offset = $this->mPastTheEndIndex;
 454                 } else {
 455                         $offset = $this->mOffset;
 456                 }
 457                 foreach ( $this->mLimitsShown as $limit ) {
 458                         $links[] = $this->makeLink( $wgLang->formatNum( $limit ),
 459                                 array( 'offset' => $offset, 'limit' => $limit ), 'num' );
 460                 }
 461                 return $links;
 462         }
 463
 464         /**
 465          * Abstract formatting function. This should return an HTML string
 466          * representing the result row $row. Rows will be concatenated and
 467          * returned by getBody()
 468          */
 469         abstract function formatRow( $row );
 470
 471         /**
 472          * This function should be overridden to provide all parameters
 473          * needed for the main paged query. It returns an associative
 474          * array with the following elements:
 475          *    tables => Table(s) for passing to Database::select()
 476          *    fields => Field(s) for passing to Database::select(), may be *
 477          *    conds => WHERE conditions
 478          *    options => option array
 479          *    join_conds => JOIN conditions
 480          */
 481         abstract function getQueryInfo();
 482
 483         /**
 484          * This function should be overridden to return the name of the index fi-
 485          * eld.  If the pager supports multiple orders, it may return an array of
 486          * 'querykey' => 'indexfield' pairs, so that a request with &count=querykey
 487          * will use indexfield to sort.  In this case, the first returned key is
 488          * the default.
 489          *
 490          * Needless to say, it's really not a good idea to use a non-unique index
 491          * for this!  That won't page right.
 492          */
 493         abstract function getIndexField();
 494
 495         /**
 496          * Return the default sorting direction: false for ascending, true for de-
 497          * scending.  You can also have an associative array of ordertype => dir,
 498          * if multiple order types are supported.  In this case getIndexField()
 499          * must return an array, and the keys of that must exactly match the keys
 500          * of this.
 501          *
 502          * For backward compatibility, this method's return value will be ignored
 503          * if $this->mDefaultDirection is already set when the constructor is
 504          * called, for instance if it's statically initialized.  In that case the
 505          * value of that variable (which must be a boolean) will be used.
 506          *
 507          * Note that despite its name, this does not return the value of the
 508          * $this->mDefaultDirection member variable.  That's the default for this
 509          * particular instantiation, which is a single value.  This is the set of
 510          * all defaults for the class.
 511          */
 512         protected function getDefaultDirections() { return false; }
 513 }
 514
 515
 516 /**
 517  * IndexPager with an alphabetic list and a formatted navigation bar
 518  * @ingroup Pager
 519  */
 520 abstract class AlphabeticPager extends IndexPager {
 521         /**
 522          * Shamelessly stolen bits from ReverseChronologicalPager,
 523          * didn't want to do class magic as may be still revamped
 524          */
 525         function getNavigationBar() {
 526                 global $wgLang;
 527
 528                 if ( !$this->isNavigationBarShown() ) return '';
 529
 530                 if( isset( $this->mNavigationBar ) ) {
 531                         return $this->mNavigationBar;
 532                 }
 533
 534                 $opts = array( 'parsemag', 'escapenoentities' );
 535                 $linkTexts = array(
 536                         'prev' => wfMsgExt( 'prevn', $opts, $wgLang->formatNum( $this->mLimit ) ),
 537                         'next' => wfMsgExt( 'nextn', $opts, $wgLang->formatNum($this->mLimit ) ),
 538                         'first' => wfMsgExt( 'page_first', $opts ),
 539                         'last' => wfMsgExt( 'page_last', $opts )
 540                 );
 541
 542                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 543                 $limitLinks = $this->getLimitLinks();
 544                 $limits = $wgLang->pipeList( $limitLinks );
 545
 546                 $this->mNavigationBar =
 547                         "(" . $wgLang->pipeList( array( $pagingLinks['first'], $pagingLinks['last'] ) ) . ") " .
 548                         wfMsgHtml( 'viewprevnext', $pagingLinks['prev'],
 549                         $pagingLinks['next'], $limits );
 550
 551                 if( !is_array( $this->getIndexField() ) ) {
 552                         # Early return to avoid undue nesting
 553                         return $this->mNavigationBar;
 554                 }
 555
 556                 $extra = '';
 557                 $first = true;
 558                 $msgs = $this->getOrderTypeMessages();
 559                 foreach( array_keys( $msgs ) as $order ) {
 560                         if( $first ) {
 561                                 $first = false;
 562                         } else {
 563                                 $extra .= wfMsgExt( 'pipe-separator' , 'escapenoentities' );
 564                         }
 565
 566                         if( $order == $this->mOrderType ) {
 567                                 $extra .= wfMsgHTML( $msgs[$order] );
 568                         } else {
 569                                 $extra .= $this->makeLink(
 570                                         wfMsgHTML( $msgs[$order] ),
 571                                         array( 'order' => $order )
 572                                 );
 573                         }
 574                 }
 575
 576                 if( $extra !== '' ) {
 577                         $this->mNavigationBar .= " ($extra)";
 578                 }
 579
 580                 return $this->mNavigationBar;
 581         }
 582
 583         /**
 584          * If this supports multiple order type messages, give the message key for
 585          * enabling each one in getNavigationBar.  The return type is an associa-
 586          * tive array whose keys must exactly match the keys of the array returned
 587          * by getIndexField(), and whose values are message keys.
 588          * @return array
 589          */
 590         protected function getOrderTypeMessages() {
 591                 return null;
 592         }
 593 }
 594
 595 /**
 596  * IndexPager with a formatted navigation bar
 597  * @ingroup Pager
 598  */
 599 abstract class ReverseChronologicalPager extends IndexPager {
 600         public $mDefaultDirection = true;
 601         public $mYear;
 602         public $mMonth;
 603
 604         function __construct() {
 605                 parent::__construct();
 606         }
 607
 608         function getNavigationBar() {
 609                 global $wgLang;
 610
 611                 if ( !$this->isNavigationBarShown() ) return '';
 612
 613                 if ( isset( $this->mNavigationBar ) ) {
 614                         return $this->mNavigationBar;
 615                 }
 616                 $nicenumber = $wgLang->formatNum( $this->mLimit );
 617                 $linkTexts = array(
 618                         'prev' => wfMsgExt( 'pager-newer-n', array( 'parsemag', 'escape' ), $nicenumber ),
 619                         'next' => wfMsgExt( 'pager-older-n', array( 'parsemag', 'escape' ), $nicenumber ),
 620                         'first' => wfMsgHtml( 'histlast' ),
 621                         'last' => wfMsgHtml( 'histfirst' )
 622                 );
 623
 624                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 625                 $limitLinks = $this->getLimitLinks();
 626                 $limits = $wgLang->pipeList( $limitLinks );
 627
 628                 $this->mNavigationBar = "({$pagingLinks['first']}" . wfMsgExt( 'pipe-separator' , 'escapenoentities' ) . "{$pagingLinks['last']}) " .
 629                         wfMsgHtml("viewprevnext", $pagingLinks['prev'], $pagingLinks['next'], $limits);
 630                 return $this->mNavigationBar;
 631         }
 632
 633         function getDateCond( $year, $month ) {
 634                 $year = intval($year);
 635                 $month = intval($month);
 636                 // Basic validity checks
 637                 $this->mYear = $year > 0 ? $year : false;
 638                 $this->mMonth = ($month > 0 && $month < 13) ? $month : false;
 639                 // Given an optional year and month, we need to generate a timestamp
 640                 // to use as "WHERE rev_timestamp <= result"
 641                 // Examples: year = 2006 equals < 20070101 (+000000)
 642                 // year=2005, month=1    equals < 20050201
 643                 // year=2005, month=12   equals < 20060101
 644                 if ( !$this->mYear && !$this->mMonth ) {
 645                         return;
 646                 }
 647                 if ( $this->mYear ) {
 648                         $year = $this->mYear;
 649                 } else {
 650                         // If no year given, assume the current one
 651                         $year = gmdate( 'Y' );
 652                         // If this month hasn't happened yet this year, go back to last year's month
 653                         if( $this->mMonth > gmdate( 'n' ) ) {
 654                                 $year--;
 655                         }
 656                 }
 657                 if ( $this->mMonth ) {
 658                         $month = $this->mMonth + 1;
 659                         // For December, we want January 1 of the next year
 660                         if ($month > 12) {
 661                                 $month = 1;
 662                                 $year++;
 663                         }
 664                 } else {
 665                         // No month implies we want up to the end of the year in question
 666                         $month = 1;
 667                         $year++;
 668                 }
 669                 // Y2K38 bug
 670                 if ( $year > 2032 ) {
 671                         $year = 2032;
 672                 }
 673                 $ymd = (int)sprintf( "%04d%02d01", $year, $month );
 674                 if ( $ymd > 20320101 ) {
 675                         $ymd = 20320101;
 676                 }
 677                 $this->mOffset = $this->mDb->timestamp( "${ymd}000000" );
 678         }
 679 }
 680
 681 /**
 682  * Table-based display with a user-selectable sort order
 683  * @ingroup Pager
 684  */
 685 abstract class TablePager extends IndexPager {
 686         var $mSort;
 687         var $mCurrentRow;
 688
 689         function __construct() {
 690                 global $wgRequest;
 691                 $this->mSort = $wgRequest->getText( 'sort' );
 692                 if ( !array_key_exists( $this->mSort, $this->getFieldNames() ) ) {
 693                         $this->mSort = $this->getDefaultSort();
 694                 }
 695                 if ( $wgRequest->getBool( 'asc' ) ) {
 696                         $this->mDefaultDirection = false;
 697                 } elseif ( $wgRequest->getBool( 'desc' ) ) {
 698                         $this->mDefaultDirection = true;
 699                 } /* Else leave it at whatever the class default is */
 700
 701                 parent::__construct();
 702         }
 703
 704         function getStartBody() {
 705                 global $wgStylePath;
 706                 $tableClass = htmlspecialchars( $this->getTableClass() );
 707                 $sortClass = htmlspecialchars( $this->getSortHeaderClass() );
 708
 709                 $s = "<table border='1' class=\"$tableClass\"><thead><tr>\n";
 710                 $fields = $this->getFieldNames();
 711
 712                 # Make table header
 713                 foreach ( $fields as $field => $name ) {
 714                         if ( strval( $name ) == '' ) {
 715                                 $s .= "<th>&nbsp;</th>\n";
 716                         } elseif ( $this->isFieldSortable( $field ) ) {
 717                                 $query = array( 'sort' => $field, 'limit' => $this->mLimit );
 718                                 if ( $field == $this->mSort ) {
 719                                         # This is the sorted column
 720                                         # Prepare a link that goes in the other sort order
 721                                         if ( $this->mDefaultDirection ) {
 722                                                 # Descending
 723                                                 $image = 'Arr_u.png';
 724                                                 $query['asc'] = '1';
 725                                                 $query['desc'] = '';
 726                                                 $alt = htmlspecialchars( wfMsg( 'descending_abbrev' ) );
 727                                         } else {
 728                                                 # Ascending
 729                                                 $image = 'Arr_d.png';
 730                                                 $query['asc'] = '';
 731                                                 $query['desc'] = '1';
 732                                                 $alt = htmlspecialchars( wfMsg( 'ascending_abbrev' ) );
 733                                         }
 734                                         $image = htmlspecialchars( "$wgStylePath/common/images/$image" );
 735                                         $link = $this->makeLink(
 736                                                 "<img width=\"12\" height=\"12\" alt=\"$alt\" src=\"$image\" />" .
 737                                                 htmlspecialchars( $name ), $query );
 738                                         $s .= "<th class=\"$sortClass\">$link</th>\n";
 739                                 } else {
 740                                         $s .= '<th>' . $this->makeLink( htmlspecialchars( $name ), $query ) . "</th>\n";
 741                                 }
 742                         } else {
 743                                 $s .= '<th>' . htmlspecialchars( $name ) . "</th>\n";
 744                         }
 745                 }
 746                 $s .= "</tr></thead><tbody>\n";
 747                 return $s;
 748         }
 749
 750         function getEndBody() {
 751                 return "</tbody></table>\n";
 752         }
 753
 754         function getEmptyBody() {
 755                 $colspan = count( $this->getFieldNames() );
 756                 $msgEmpty = wfMsgHtml( 'table_pager_empty' );
 757                 return "<tr><td colspan=\"$colspan\">$msgEmpty</td></tr>\n";
 758         }
 759
 760         function formatRow( $row ) {
 761                 $this->mCurrentRow = $row;      # In case formatValue etc need to know
 762                 $s = Xml::openElement( 'tr', $this->getRowAttrs($row) );
 763                 $fieldNames = $this->getFieldNames();
 764                 foreach ( $fieldNames as $field => $name ) {
 765                         $value = isset( $row->$field ) ? $row->$field : null;
 766                         $formatted = strval( $this->formatValue( $field, $value ) );
 767                         if ( $formatted == '' ) {
 768                                 $formatted = '&nbsp;';
 769                         }
 770                         $s .= Xml::tags( 'td', $this->getCellAttrs( $field, $value ), $formatted );
 771                 }
 772                 $s .= "</tr>\n";
 773                 return $s;
 774         }
 775
 776         /**
 777          * Get a class name to be applied to the given row.
 778          * @param object $row The database result row
 779          */
 780         function getRowClass( $row ) {
 781                 return '';
 782         }
 783
 784         /**
 785          * Get attributes to be applied to the given row.
 786          * @param object $row The database result row
 787          * @return associative array
 788          */
 789         function getRowAttrs( $row ) {
 790                 return array( 'class' => $this->getRowClass( $row ) );
 791         }
 792
 793         /**
 794          * Get any extra attributes to be applied to the given cell. Don't
 795          * take this as an excuse to hardcode styles; use classes and
 796          * CSS instead.  Row context is available in $this->mCurrentRow
 797          * @param $field The column
 798          * @param $value The cell contents
 799          * @return associative array
 800          */
 801         function getCellAttrs( $field, $value ) {
 802                 return array( 'class' => 'TablePager_col_' . $field );
 803         }
 804
 805         function getIndexField() {
 806                 return $this->mSort;
 807         }
 808
 809         function getTableClass() {
 810                 return 'TablePager';
 811         }
 812
 813         function getNavClass() {
 814                 return 'TablePager_nav';
 815         }
 816
 817         function getSortHeaderClass() {
 818                 return 'TablePager_sort';
 819         }
 820
 821         /**
 822          * A navigation bar with images
 823          */
 824         function getNavigationBar() {
 825                 global $wgStylePath, $wgContLang;
 826
 827                 if ( !$this->isNavigationBarShown() ) return '';
 828
 829                 $path = "$wgStylePath/common/images";
 830                 $labels = array(
 831                         'first' => 'table_pager_first',
 832                         'prev' => 'table_pager_prev',
 833                         'next' => 'table_pager_next',
 834                         'last' => 'table_pager_last',
 835                 );
 836                 $images = array(
 837                         'first' => $wgContLang->isRTL() ? 'arrow_last_25.png' : 'arrow_first_25.png',
 838                         'prev' =>  $wgContLang->isRTL() ? 'arrow_right_25.png' : 'arrow_left_25.png',
 839                         'next' =>  $wgContLang->isRTL() ? 'arrow_left_25.png' : 'arrow_right_25.png',
 840                         'last' =>  $wgContLang->isRTL() ? 'arrow_first_25.png' : 'arrow_last_25.png',
 841                 );
 842                 $disabledImages = array(
 843                         'first' => $wgContLang->isRTL() ? 'arrow_disabled_last_25.png' : 'arrow_disabled_first_25.png',
 844                         'prev' =>  $wgContLang->isRTL() ? 'arrow_disabled_right_25.png' : 'arrow_disabled_left_25.png',
 845                         'next' =>  $wgContLang->isRTL() ? 'arrow_disabled_left_25.png' : 'arrow_disabled_right_25.png',
 846                         'last' =>  $wgContLang->isRTL() ? 'arrow_disabled_first_25.png' : 'arrow_disabled_last_25.png',
 847                 );
 848
 849                 $linkTexts = array();
 850                 $disabledTexts = array();
 851                 foreach ( $labels as $type => $label ) {
 852                         $msgLabel = wfMsgHtml( $label );
 853                         $linkTexts[$type] = "<img src=\"$path/{$images[$type]}\" alt=\"$msgLabel\"/><br/>$msgLabel";
 854                         $disabledTexts[$type] = "<img src=\"$path/{$disabledImages[$type]}\" alt=\"$msgLabel\"/><br/>$msgLabel";
 855                 }
 856                 $links = $this->getPagingLinks( $linkTexts, $disabledTexts );
 857
 858                 $navClass = htmlspecialchars( $this->getNavClass() );
 859                 $s = "<table class=\"$navClass\" align=\"center\" cellpadding=\"3\"><tr>\n";
 860                 $cellAttrs = 'valign="top" align="center" width="' . 100 / count( $links ) . '%"';
 861                 foreach ( $labels as $type => $label ) {
 862                         $s .= "<td $cellAttrs>{$links[$type]}</td>\n";
 863                 }
 864                 $s .= "</tr></table>\n";
 865                 return $s;
 866         }
 867
 868         /**
 869          * Get a <select> element which has options for each of the allowed limits
 870          */
 871         function getLimitSelect() {
 872                 global $wgLang;
 873                 $s = "<select name=\"limit\">";
 874                 foreach ( $this->mLimitsShown as $limit ) {
 875                         $selected = $limit == $this->mLimit ? 'selected="selected"' : '';
 876                         $formattedLimit = $wgLang->formatNum( $limit );
 877                         $s .= "<option value=\"$limit\" $selected>$formattedLimit</option>\n";
 878                 }
 879                 $s .= "</select>";
 880                 return $s;
 881         }
 882
 883         /**
 884          * Get <input type="hidden"> elements for use in a method="get" form.
 885          * Resubmits all defined elements of the $_GET array, except for a
 886          * blacklist, passed in the $blacklist parameter.
 887          */
 888         function getHiddenFields( $blacklist = array() ) {
 889                 $blacklist = (array)$blacklist;
 890                 $query = $_GET;
 891                 foreach ( $blacklist as $name ) {
 892                         unset( $query[$name] );
 893                 }
 894                 $s = '';
 895                 foreach ( $query as $name => $value ) {
 896                         $encName = htmlspecialchars( $name );
 897                         $encValue = htmlspecialchars( $value );
 898                         $s .= "<input type=\"hidden\" name=\"$encName\" value=\"$encValue\"/>\n";
 899                 }
 900                 return $s;
 901         }
 902
 903         /**
 904          * Get a form containing a limit selection dropdown
 905          */
 906         function getLimitForm() {
 907                 # Make the select with some explanatory text
 908                 $url = $this->getTitle()->escapeLocalURL();
 909                 $msgSubmit = wfMsgHtml( 'table_pager_limit_submit' );
 910                 return
 911                         "<form method=\"get\" action=\"$url\">" .
 912                         wfMsgHtml( 'table_pager_limit', $this->getLimitSelect() ) .
 913                         "\n<input type=\"submit\" value=\"$msgSubmit\"/>\n" .
 914                         $this->getHiddenFields( array('limit','title') ) .
 915                         "</form>\n";
 916         }
 917
 918         /**
 919          * Return true if the named field should be sortable by the UI, false
 920          * otherwise
 921          *
 922          * @param string $field
 923          */
 924         abstract function isFieldSortable( $field );
 925
 926         /**
 927          * Format a table cell. The return value should be HTML, but use an empty
 928          * string not &nbsp; for empty cells. Do not include the <td> and </td>.
 929          *
 930          * The current result row is available as $this->mCurrentRow, in case you
 931          * need more context.
 932          *
 933          * @param string $name The database field name
 934          * @param string $value The value retrieved from the database
 935          */
 936         abstract function formatValue( $name, $value );
 937
 938         /**
 939          * The database field name used as a default sort order
 940          */
 941         abstract function getDefaultSort();
 942
 943         /**
 944          * An array mapping database field names to a textual description of the
 945          * field name, for use in the table header. The description should be plain
 946          * text, it will be HTML-escaped later.
 947          */
 948         abstract function getFieldNames();
 949 }