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 HistoryPage.php and
  54  *  SpecialBlockList.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 column,
  71          * for one ordering, even if multiple orderings are supported.
  72          */
  73         protected $mIndexField;
  74         /**
  75          * An array of secondary columns to order by. These fields are not part of the offset.
  76          * This is a column list for one ordering, even if multiple orderings are supported.
  77          */
  78         protected $mExtraSortFields;
  79         /** For pages that support multiple types of ordering, which one to use.
  80          */
  81         protected $mOrderType;
  82         /**
  83          * $mDefaultDirection gives the direction to use when sorting results:
  84          * false for ascending, true for descending.  If $mIsBackwards is set, we
  85          * start from the opposite end, but we still sort the page itself according
  86          * to $mDefaultDirection.  E.g., if $mDefaultDirection is false but we're
  87          * going backwards, we'll display the last page of results, but the last
  88          * result will be at the bottom, not the top.
  89          *
  90          * Like $mIndexField, $mDefaultDirection will be a single value even if the
  91          * class supports multiple default directions for different order types.
  92          */
  93         public $mDefaultDirection;
  94         public $mIsBackwards;
  95
  96         /** True if the current result set is the first one */
  97         public $mIsFirst;
  98
  99         /**
 100          * Result object for the query. Warning: seek before use.
 101          *
 102          * @var ResultWrapper
 103          */
 104         public $mResult;
 105
 106         public function __construct() {
 107                 global $wgRequest, $wgUser;
 108                 $this->mRequest = $wgRequest;
 109
 110                 # NB: the offset is quoted, not validated. It is treated as an
 111                 # arbitrary string to support the widest variety of index types. Be
 112                 # careful outputting it into HTML!
 113                 $this->mOffset = $this->mRequest->getText( 'offset' );
 114
 115                 # Use consistent behavior for the limit options
 116                 $this->mDefaultLimit = intval( $wgUser->getOption( 'rclimit' ) );
 117                 list( $this->mLimit, /* $offset */ ) = $this->mRequest->getLimitOffset();
 118
 119                 $this->mIsBackwards = ( $this->mRequest->getVal( 'dir' ) == 'prev' );
 120                 $this->mDb = wfGetDB( DB_SLAVE );
 121
 122                 $index = $this->getIndexField();
 123                 $extraSort = $this->getExtraSortFields();
 124                 $order = $this->mRequest->getVal( 'order' );
 125                 if( is_array( $index ) && isset( $index[$order] ) ) {
 126                         $this->mOrderType = $order;
 127                         $this->mIndexField = $index[$order];
 128                         $this->mExtraSortFields = (array)$extraSort[$order];
 129                 } elseif( is_array( $index ) ) {
 130                         # First element is the default
 131                         reset( $index );
 132                         list( $this->mOrderType, $this->mIndexField ) = each( $index );
 133                         $this->mExtraSortFields = (array)$extraSort[$this->mOrderType];
 134                 } else {
 135                         # $index is not an array
 136                         $this->mOrderType = null;
 137                         $this->mIndexField = $index;
 138                         $this->mExtraSortFields = (array)$extraSort;
 139                 }
 140
 141                 if( !isset( $this->mDefaultDirection ) ) {
 142                         $dir = $this->getDefaultDirections();
 143                         $this->mDefaultDirection = is_array( $dir )
 144                                 ? $dir[$this->mOrderType]
 145                                 : $dir;
 146                 }
 147         }
 148
 149         /**
 150          * Do the query, using information from the object context. This function
 151          * has been kept minimal to make it overridable if necessary, to allow for
 152          * result sets formed from multiple DB queries.
 153          */
 154         public function doQuery() {
 155                 # Use the child class name for profiling
 156                 $fname = __METHOD__ . ' (' . get_class( $this ) . ')';
 157                 wfProfileIn( $fname );
 158
 159                 $descending = ( $this->mIsBackwards == $this->mDefaultDirection );
 160                 # Plus an extra row so that we can tell the "next" link should be shown
 161                 $queryLimit = $this->mLimit + 1;
 162
 163                 $this->mResult = $this->reallyDoQuery(
 164                         $this->mOffset,
 165                         $queryLimit,
 166                         $descending
 167                 );
 168                 $this->extractResultInfo( $this->mOffset, $queryLimit, $this->mResult );
 169                 $this->mQueryDone = true;
 170
 171                 $this->preprocessResults( $this->mResult );
 172                 $this->mResult->rewind(); // Paranoia
 173
 174                 wfProfileOut( $fname );
 175         }
 176
 177         /**
 178          * @return ResultWrapper The result wrapper.
 179          */
 180         function getResult() {
 181                 return $this->mResult;
 182         }
 183
 184         /**
 185          * Set the offset from an other source than $wgRequest
 186          */
 187         function setOffset( $offset ) {
 188                 $this->mOffset = $offset;
 189         }
 190         /**
 191          * Set the limit from an other source than $wgRequest
 192          */
 193         function setLimit( $limit ) {
 194                 $this->mLimit = $limit;
 195         }
 196
 197         /**
 198          * Extract some useful data from the result object for use by
 199          * the navigation bar, put it into $this
 200          *
 201          * @param $offset String: index offset, inclusive
 202          * @param $limit Integer: exact query limit
 203          * @param $res ResultWrapper
 204          */
 205         function extractResultInfo( $offset, $limit, ResultWrapper $res ) {
 206                 $numRows = $res->numRows();
 207                 if ( $numRows ) {
 208                         # Remove any table prefix from index field
 209                         $parts = explode( '.', $this->mIndexField );
 210                         $indexColumn = end( $parts );
 211
 212                         $row = $res->fetchRow();
 213                         $firstIndex = $row[$indexColumn];
 214
 215                         # Discard the extra result row if there is one
 216                         if ( $numRows > $this->mLimit && $numRows > 1 ) {
 217                                 $res->seek( $numRows - 1 );
 218                                 $this->mPastTheEndRow = $res->fetchObject();
 219                                 $indexField = $this->mIndexField;
 220                                 $this->mPastTheEndIndex = $this->mPastTheEndRow->$indexField;
 221                                 $res->seek( $numRows - 2 );
 222                                 $row = $res->fetchRow();
 223                                 $lastIndex = $row[$indexColumn];
 224                         } else {
 225                                 $this->mPastTheEndRow = null;
 226                                 # Setting indexes to an empty string means that they will be
 227                                 # omitted if they would otherwise appear in URLs. It just so
 228                                 # happens that this  is the right thing to do in the standard
 229                                 # UI, in all the relevant cases.
 230                                 $this->mPastTheEndIndex = '';
 231                                 $res->seek( $numRows - 1 );
 232                                 $row = $res->fetchRow();
 233                                 $lastIndex = $row[$indexColumn];
 234                         }
 235                 } else {
 236                         $firstIndex = '';
 237                         $lastIndex = '';
 238                         $this->mPastTheEndRow = null;
 239                         $this->mPastTheEndIndex = '';
 240                 }
 241
 242                 if ( $this->mIsBackwards ) {
 243                         $this->mIsFirst = ( $numRows < $limit );
 244                         $this->mIsLast = ( $offset == '' );
 245                         $this->mLastShown = $firstIndex;
 246                         $this->mFirstShown = $lastIndex;
 247                 } else {
 248                         $this->mIsFirst = ( $offset == '' );
 249                         $this->mIsLast = ( $numRows < $limit );
 250                         $this->mLastShown = $lastIndex;
 251                         $this->mFirstShown = $firstIndex;
 252                 }
 253         }
 254
 255         /**
 256          * Get some text to go in brackets in the "function name" part of the SQL comment
 257          *
 258          * @return String
 259          */
 260         function getSqlComment() {
 261                 return get_class( $this );
 262         }
 263
 264         /**
 265          * Do a query with specified parameters, rather than using the object
 266          * context
 267          *
 268          * @param $offset String: index offset, inclusive
 269          * @param $limit Integer: exact query limit
 270          * @param $descending Boolean: query direction, false for ascending, true for descending
 271          * @return ResultWrapper
 272          */
 273         function reallyDoQuery( $offset, $limit, $descending ) {
 274                 $fname = __METHOD__ . ' (' . $this->getSqlComment() . ')';
 275                 $info = $this->getQueryInfo();
 276                 $tables = $info['tables'];
 277                 $fields = $info['fields'];
 278                 $conds = isset( $info['conds'] ) ? $info['conds'] : array();
 279                 $options = isset( $info['options'] ) ? $info['options'] : array();
 280                 $join_conds = isset( $info['join_conds'] ) ? $info['join_conds'] : array();
 281                 $sortColumns = array_merge( array( $this->mIndexField ), $this->mExtraSortFields );
 282                 if ( $descending ) {
 283                         $options['ORDER BY'] = implode( ',', $sortColumns );
 284                         $operator = '>';
 285                 } else {
 286                         $orderBy = array();
 287                         foreach ( $sortColumns as $col ) {
 288                                 $orderBy[] = $col . ' DESC';
 289                         }
 290                         $options['ORDER BY'] = implode( ',', $orderBy );
 291                         $operator = '<';
 292                 }
 293                 if ( $offset != '' ) {
 294                         $conds[] = $this->mIndexField . $operator . $this->mDb->addQuotes( $offset );
 295                 }
 296                 $options['LIMIT'] = intval( $limit );
 297                 $res = $this->mDb->select( $tables, $fields, $conds, $fname, $options, $join_conds );
 298                 return new ResultWrapper( $this->mDb, $res );
 299         }
 300
 301         /**
 302          * Pre-process results; useful for performing batch existence checks, etc.
 303          *
 304          * @param $result ResultWrapper
 305          */
 306         protected function preprocessResults( $result ) {}
 307
 308         /**
 309          * Get the formatted result list. Calls getStartBody(), formatRow() and
 310          * getEndBody(), concatenates the results and returns them.
 311          *
 312          * @return String
 313          */
 314         function getBody() {
 315                 if ( !$this->mQueryDone ) {
 316                         $this->doQuery();
 317                 }
 318                 # Don't use any extra rows returned by the query
 319                 $numRows = min( $this->mResult->numRows(), $this->mLimit );
 320
 321                 $s = $this->getStartBody();
 322                 if ( $numRows ) {
 323                         if ( $this->mIsBackwards ) {
 324                                 for ( $i = $numRows - 1; $i >= 0; $i-- ) {
 325                                         $this->mResult->seek( $i );
 326                                         $row = $this->mResult->fetchObject();
 327                                         $s .= $this->formatRow( $row );
 328                                 }
 329                         } else {
 330                                 $this->mResult->seek( 0 );
 331                                 for ( $i = 0; $i < $numRows; $i++ ) {
 332                                         $row = $this->mResult->fetchObject();
 333                                         $s .= $this->formatRow( $row );
 334                                 }
 335                         }
 336                 } else {
 337                         $s .= $this->getEmptyBody();
 338                 }
 339                 $s .= $this->getEndBody();
 340                 return $s;
 341         }
 342
 343         /**
 344          * Make a self-link
 345          *
 346          * @param $text String: text displayed on the link
 347          * @param $query Array: associative array of paramter to be in the query string
 348          * @param $type String: value of the "rel" attribute
 349          * @return String: HTML fragment
 350          */
 351         function makeLink($text, $query = null, $type=null) {
 352                 if ( $query === null ) {
 353                         return $text;
 354                 }
 355
 356                 $attrs = array();
 357                 if( in_array( $type, array( 'first', 'prev', 'next', 'last' ) ) ) {
 358                         # HTML5 rel attributes
 359                         $attrs['rel'] = $type;
 360                 }
 361
 362                 if( $type ) {
 363                         $attrs['class'] = "mw-{$type}link";
 364                 }
 365                 return $this->getSkin()->link(
 366                         $this->getTitle(),
 367                         $text,
 368                         $attrs,
 369                         $query + $this->getDefaultQuery(),
 370                         array( 'noclasses', 'known' )
 371                 );
 372         }
 373
 374         /**
 375          * Hook into getBody(), allows text to be inserted at the start. This
 376          * will be called even if there are no rows in the result set.
 377          *
 378          * @return String
 379          */
 380         function getStartBody() {
 381                 return '';
 382         }
 383
 384         /**
 385          * Hook into getBody() for the end of the list
 386          *
 387          * @return String
 388          */
 389         function getEndBody() {
 390                 return '';
 391         }
 392
 393         /**
 394          * Hook into getBody(), for the bit between the start and the
 395          * end when there are no rows
 396          *
 397          * @return String
 398          */
 399         function getEmptyBody() {
 400                 return '';
 401         }
 402
 403         /**
 404          * Title used for self-links. Override this if you want to be able to
 405          * use a title other than $wgTitle
 406          *
 407          * @return Title object
 408          */
 409         function getTitle() {
 410                 return $GLOBALS['wgTitle'];
 411         }
 412
 413         /**
 414          * Get the current skin. This can be overridden if necessary.
 415          *
 416          * @return Skin object
 417          */
 418         function getSkin() {
 419                 if ( !isset( $this->mSkin ) ) {
 420                         global $wgUser;
 421                         $this->mSkin = $wgUser->getSkin();
 422                 }
 423                 return $this->mSkin;
 424         }
 425
 426         /**
 427          * Get an array of query parameters that should be put into self-links.
 428          * By default, all parameters passed in the URL are used, except for a
 429          * short blacklist.
 430          *
 431          * @return Associative array
 432          */
 433         function getDefaultQuery() {
 434                 global $wgRequest;
 435
 436                 if ( !isset( $this->mDefaultQuery ) ) {
 437                         $this->mDefaultQuery = $wgRequest->getQueryValues();
 438                         unset( $this->mDefaultQuery['title'] );
 439                         unset( $this->mDefaultQuery['dir'] );
 440                         unset( $this->mDefaultQuery['offset'] );
 441                         unset( $this->mDefaultQuery['limit'] );
 442                         unset( $this->mDefaultQuery['order'] );
 443                         unset( $this->mDefaultQuery['month'] );
 444                         unset( $this->mDefaultQuery['year'] );
 445                 }
 446                 return $this->mDefaultQuery;
 447         }
 448
 449         /**
 450          * Get the number of rows in the result set
 451          *
 452          * @return Integer
 453          */
 454         function getNumRows() {
 455                 if ( !$this->mQueryDone ) {
 456                         $this->doQuery();
 457                 }
 458                 return $this->mResult->numRows();
 459         }
 460
 461         /**
 462          * Get a URL query array for the prev, next, first and last links.
 463          *
 464          * @return Array
 465          */
 466         function getPagingQueries() {
 467                 if ( !$this->mQueryDone ) {
 468                         $this->doQuery();
 469                 }
 470
 471                 # Don't announce the limit everywhere if it's the default
 472                 $urlLimit = $this->mLimit == $this->mDefaultLimit ? '' : $this->mLimit;
 473
 474                 if ( $this->mIsFirst ) {
 475                         $prev = false;
 476                         $first = false;
 477                 } else {
 478                         $prev = array(
 479                                 'dir' => 'prev',
 480                                 'offset' => $this->mFirstShown,
 481                                 'limit' => $urlLimit
 482                         );
 483                         $first = array( 'limit' => $urlLimit );
 484                 }
 485                 if ( $this->mIsLast ) {
 486                         $next = false;
 487                         $last = false;
 488                 } else {
 489                         $next = array( 'offset' => $this->mLastShown, 'limit' => $urlLimit );
 490                         $last = array( 'dir' => 'prev', 'limit' => $urlLimit );
 491                 }
 492                 return array(
 493                         'prev' => $prev,
 494                         'next' => $next,
 495                         'first' => $first,
 496                         'last' => $last
 497                 );
 498         }
 499
 500         /**
 501          * Returns whether to show the "navigation bar"
 502          *
 503          * @return Boolean
 504          */
 505         function isNavigationBarShown() {
 506                 if ( !$this->mQueryDone ) {
 507                         $this->doQuery();
 508                 }
 509                 // Hide navigation by default if there is nothing to page
 510                 return !($this->mIsFirst && $this->mIsLast);
 511         }
 512
 513         /**
 514          * Get paging links. If a link is disabled, the item from $disabledTexts
 515          * will be used. If there is no such item, the unlinked text from
 516          * $linkTexts will be used. Both $linkTexts and $disabledTexts are arrays
 517          * of HTML.
 518          *
 519          * @return Array
 520          */
 521         function getPagingLinks( $linkTexts, $disabledTexts = array() ) {
 522                 $queries = $this->getPagingQueries();
 523                 $links = array();
 524                 foreach ( $queries as $type => $query ) {
 525                         if ( $query !== false ) {
 526                                 $links[$type] = $this->makeLink(
 527                                         $linkTexts[$type],
 528                                         $queries[$type],
 529                                         $type
 530                                 );
 531                         } elseif ( isset( $disabledTexts[$type] ) ) {
 532                                 $links[$type] = $disabledTexts[$type];
 533                         } else {
 534                                 $links[$type] = $linkTexts[$type];
 535                         }
 536                 }
 537                 return $links;
 538         }
 539
 540         function getLimitLinks() {
 541                 global $wgLang;
 542                 $links = array();
 543                 if ( $this->mIsBackwards ) {
 544                         $offset = $this->mPastTheEndIndex;
 545                 } else {
 546                         $offset = $this->mOffset;
 547                 }
 548                 foreach ( $this->mLimitsShown as $limit ) {
 549                         $links[] = $this->makeLink(
 550                                 $wgLang->formatNum( $limit ),
 551                                 array( 'offset' => $offset, 'limit' => $limit ),
 552                                 'num'
 553                         );
 554                 }
 555                 return $links;
 556         }
 557
 558         /**
 559          * Abstract formatting function. This should return an HTML string
 560          * representing the result row $row. Rows will be concatenated and
 561          * returned by getBody()
 562          *
 563          * @param $row Object: database row
 564          * @return String
 565          */
 566         abstract function formatRow( $row );
 567
 568         /**
 569          * This function should be overridden to provide all parameters
 570          * needed for the main paged query. It returns an associative
 571          * array with the following elements:
 572          *    tables => Table(s) for passing to Database::select()
 573          *    fields => Field(s) for passing to Database::select(), may be *
 574          *    conds => WHERE conditions
 575          *    options => option array
 576          *    join_conds => JOIN conditions
 577          *
 578          * @return Array
 579          */
 580         abstract function getQueryInfo();
 581
 582         /**
 583          * This function should be overridden to return the name of the index fi-
 584          * eld.  If the pager supports multiple orders, it may return an array of
 585          * 'querykey' => 'indexfield' pairs, so that a request with &count=querykey
 586          * will use indexfield to sort.  In this case, the first returned key is
 587          * the default.
 588          *
 589          * Needless to say, it's really not a good idea to use a non-unique index
 590          * for this!  That won't page right.
 591          *
 592          * @return string|Array
 593          */
 594         abstract function getIndexField();
 595
 596         /**
 597          * This function should be overridden to return the names of secondary columns
 598          * to order by in addition to the column in getIndexField(). These fields will
 599          * not be used in the pager offset or in any links for users.
 600          *
 601          * If getIndexField() returns an array of 'querykey' => 'indexfield' pairs then
 602          * this must return a corresponding array of 'querykey' => array( fields...) pairs,
 603          * so that a request with &count=querykey will use array( fields...) to sort.
 604          *
 605          * This is useful for pagers that GROUP BY a unique column (say page_id)
 606          * and ORDER BY another (say page_len). Using GROUP BY and ORDER BY both on
 607          * page_len,page_id avoids temp tables (given a page_len index). This would
 608          * also work if page_id was non-unique but we had a page_len,page_id index.
 609          *
 610          * @return Array
 611          */
 612         protected function getExtraSortFields() { return array(); }
 613
 614         /**
 615          * Return the default sorting direction: false for ascending, true for de-
 616          * scending.  You can also have an associative array of ordertype => dir,
 617          * if multiple order types are supported.  In this case getIndexField()
 618          * must return an array, and the keys of that must exactly match the keys
 619          * of this.
 620          *
 621          * For backward compatibility, this method's return value will be ignored
 622          * if $this->mDefaultDirection is already set when the constructor is
 623          * called, for instance if it's statically initialized.  In that case the
 624          * value of that variable (which must be a boolean) will be used.
 625          *
 626          * Note that despite its name, this does not return the value of the
 627          * $this->mDefaultDirection member variable.  That's the default for this
 628          * particular instantiation, which is a single value.  This is the set of
 629          * all defaults for the class.
 630          *
 631          * @return Boolean
 632          */
 633         protected function getDefaultDirections() { return false; }
 634 }
 635
 636
 637 /**
 638  * IndexPager with an alphabetic list and a formatted navigation bar
 639  * @ingroup Pager
 640  */
 641 abstract class AlphabeticPager extends IndexPager {
 642         /**
 643          * Shamelessly stolen bits from ReverseChronologicalPager,
 644          * didn't want to do class magic as may be still revamped
 645          */
 646         function getNavigationBar() {
 647                 global $wgLang;
 648
 649                 if ( !$this->isNavigationBarShown() ) return '';
 650
 651                 if( isset( $this->mNavigationBar ) ) {
 652                         return $this->mNavigationBar;
 653                 }
 654
 655                 $opts = array( 'parsemag', 'escapenoentities' );
 656                 $linkTexts = array(
 657                         'prev' => wfMsgExt(
 658                                 'prevn',
 659                                 $opts,
 660                                 $wgLang->formatNum( $this->mLimit )
 661                         ),
 662                         'next' => wfMsgExt(
 663                                 'nextn',
 664                                 $opts,
 665                                 $wgLang->formatNum($this->mLimit )
 666                         ),
 667                         'first' => wfMsgExt( 'page_first', $opts ),
 668                         'last' => wfMsgExt( 'page_last', $opts )
 669                 );
 670
 671                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 672                 $limitLinks = $this->getLimitLinks();
 673                 $limits = $wgLang->pipeList( $limitLinks );
 674
 675                 $this->mNavigationBar =
 676                         "(" . $wgLang->pipeList(
 677                                 array( $pagingLinks['first'],
 678                                 $pagingLinks['last'] )
 679                         ) . ") " .
 680                         wfMsgHtml( 'viewprevnext', $pagingLinks['prev'],
 681                         $pagingLinks['next'], $limits );
 682
 683                 if( !is_array( $this->getIndexField() ) ) {
 684                         # Early return to avoid undue nesting
 685                         return $this->mNavigationBar;
 686                 }
 687
 688                 $extra = '';
 689                 $first = true;
 690                 $msgs = $this->getOrderTypeMessages();
 691                 foreach( array_keys( $msgs ) as $order ) {
 692                         if( $first ) {
 693                                 $first = false;
 694                         } else {
 695                                 $extra .= wfMsgExt( 'pipe-separator' , 'escapenoentities' );
 696                         }
 697
 698                         if( $order == $this->mOrderType ) {
 699                                 $extra .= wfMsgHTML( $msgs[$order] );
 700                         } else {
 701                                 $extra .= $this->makeLink(
 702                                         wfMsgHTML( $msgs[$order] ),
 703                                         array( 'order' => $order )
 704                                 );
 705                         }
 706                 }
 707
 708                 if( $extra !== '' ) {
 709                         $this->mNavigationBar .= " ($extra)";
 710                 }
 711
 712                 return $this->mNavigationBar;
 713         }
 714
 715         /**
 716          * If this supports multiple order type messages, give the message key for
 717          * enabling each one in getNavigationBar.  The return type is an associa-
 718          * tive array whose keys must exactly match the keys of the array returned
 719          * by getIndexField(), and whose values are message keys.
 720          *
 721          * @return Array
 722          */
 723         protected function getOrderTypeMessages() {
 724                 return null;
 725         }
 726 }
 727
 728 /**
 729  * IndexPager with a formatted navigation bar
 730  * @ingroup Pager
 731  */
 732 abstract class ReverseChronologicalPager extends IndexPager {
 733         public $mDefaultDirection = true;
 734         public $mYear;
 735         public $mMonth;
 736
 737         function __construct() {
 738                 parent::__construct();
 739         }
 740
 741         function getNavigationBar() {
 742                 global $wgLang;
 743
 744                 if ( !$this->isNavigationBarShown() ) {
 745                         return '';
 746                 }
 747
 748                 if ( isset( $this->mNavigationBar ) ) {
 749                         return $this->mNavigationBar;
 750                 }
 751                 $nicenumber = $wgLang->formatNum( $this->mLimit );
 752                 $linkTexts = array(
 753                         'prev' => wfMsgExt(
 754                                 'pager-newer-n',
 755                                 array( 'parsemag', 'escape' ),
 756                                 $nicenumber
 757                         ),
 758                         'next' => wfMsgExt(
 759                                 'pager-older-n',
 760                                 array( 'parsemag', 'escape' ),
 761                                 $nicenumber
 762                         ),
 763                         'first' => wfMsgHtml( 'histlast' ),
 764                         'last' => wfMsgHtml( 'histfirst' )
 765                 );
 766
 767                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 768                 $limitLinks = $this->getLimitLinks();
 769                 $limits = $wgLang->pipeList( $limitLinks );
 770
 771                 $this->mNavigationBar = "({$pagingLinks['first']}" .
 772                         wfMsgExt( 'pipe-separator' , 'escapenoentities' ) .
 773                         "{$pagingLinks['last']}) " .
 774                         wfMsgHTML(
 775                                 'viewprevnext',
 776                                 $pagingLinks['prev'], $pagingLinks['next'],
 777                                 $limits
 778                         );
 779                 return $this->mNavigationBar;
 780         }
 781
 782         function getDateCond( $year, $month ) {
 783                 $year = intval($year);
 784                 $month = intval($month);
 785                 // Basic validity checks
 786                 $this->mYear = $year > 0 ? $year : false;
 787                 $this->mMonth = ($month > 0 && $month < 13) ? $month : false;
 788                 // Given an optional year and month, we need to generate a timestamp
 789                 // to use as "WHERE rev_timestamp <= result"
 790                 // Examples: year = 2006 equals < 20070101 (+000000)
 791                 // year=2005, month=1    equals < 20050201
 792                 // year=2005, month=12   equals < 20060101
 793                 if ( !$this->mYear && !$this->mMonth ) {
 794                         return;
 795                 }
 796                 if ( $this->mYear ) {
 797                         $year = $this->mYear;
 798                 } else {
 799                         // If no year given, assume the current one
 800                         $year = gmdate( 'Y' );
 801                         // If this month hasn't happened yet this year, go back to last year's month
 802                         if( $this->mMonth > gmdate( 'n' ) ) {
 803                                 $year--;
 804                         }
 805                 }
 806                 if ( $this->mMonth ) {
 807                         $month = $this->mMonth + 1;
 808                         // For December, we want January 1 of the next year
 809                         if ($month > 12) {
 810                                 $month = 1;
 811                                 $year++;
 812                         }
 813                 } else {
 814                         // No month implies we want up to the end of the year in question
 815                         $month = 1;
 816                         $year++;
 817                 }
 818                 // Y2K38 bug
 819                 if ( $year > 2032 ) {
 820                         $year = 2032;
 821                 }
 822                 $ymd = (int)sprintf( "%04d%02d01", $year, $month );
 823                 if ( $ymd > 20320101 ) {
 824                         $ymd = 20320101;
 825                 }
 826                 $this->mOffset = $this->mDb->timestamp( "${ymd}000000" );
 827         }
 828 }
 829
 830 /**
 831  * Table-based display with a user-selectable sort order
 832  * @ingroup Pager
 833  */
 834 abstract class TablePager extends IndexPager {
 835         var $mSort;
 836         var $mCurrentRow;
 837
 838         function __construct() {
 839                 global $wgRequest;
 840                 $this->mSort = $wgRequest->getText( 'sort' );
 841                 if ( !array_key_exists( $this->mSort, $this->getFieldNames() ) ) {
 842                         $this->mSort = $this->getDefaultSort();
 843                 }
 844                 if ( $wgRequest->getBool( 'asc' ) ) {
 845                         $this->mDefaultDirection = false;
 846                 } elseif ( $wgRequest->getBool( 'desc' ) ) {
 847                         $this->mDefaultDirection = true;
 848                 } /* Else leave it at whatever the class default is */
 849
 850                 parent::__construct();
 851         }
 852
 853         function getStartBody() {
 854                 global $wgStylePath;
 855                 $tableClass = htmlspecialchars( $this->getTableClass() );
 856                 $sortClass = htmlspecialchars( $this->getSortHeaderClass() );
 857
 858                 $s = "<table style='border:1;' class=\"mw-datatable $tableClass\"><thead><tr>\n";
 859                 $fields = $this->getFieldNames();
 860
 861                 # Make table header
 862                 foreach ( $fields as $field => $name ) {
 863                         if ( strval( $name ) == '' ) {
 864                                 $s .= "<th>&#160;</th>\n";
 865                         } elseif ( $this->isFieldSortable( $field ) ) {
 866                                 $query = array( 'sort' => $field, 'limit' => $this->mLimit );
 867                                 if ( $field == $this->mSort ) {
 868                                         # This is the sorted column
 869                                         # Prepare a link that goes in the other sort order
 870                                         if ( $this->mDefaultDirection ) {
 871                                                 # Descending
 872                                                 $image = 'Arr_d.png';
 873                                                 $query['asc'] = '1';
 874                                                 $query['desc'] = '';
 875                                                 $alt = htmlspecialchars( wfMsg( 'descending_abbrev' ) );
 876                                         } else {
 877                                                 # Ascending
 878                                                 $image = 'Arr_u.png';
 879                                                 $query['asc'] = '';
 880                                                 $query['desc'] = '1';
 881                                                 $alt = htmlspecialchars( wfMsg( 'ascending_abbrev' ) );
 882                                         }
 883                                         $image = htmlspecialchars( "$wgStylePath/common/images/$image" );
 884                                         $link = $this->makeLink(
 885                                                 "<img width=\"12\" height=\"12\" alt=\"$alt\" src=\"$image\" />" .
 886                                                 htmlspecialchars( $name ), $query );
 887                                         $s .= "<th class=\"$sortClass\">$link</th>\n";
 888                                 } else {
 889                                         $s .= '<th>' . $this->makeLink( htmlspecialchars( $name ), $query ) . "</th>\n";
 890                                 }
 891                         } else {
 892                                 $s .= '<th>' . htmlspecialchars( $name ) . "</th>\n";
 893                         }
 894                 }
 895                 $s .= "</tr></thead><tbody>\n";
 896                 return $s;
 897         }
 898
 899         function getEndBody() {
 900                 return "</tbody></table>\n";
 901         }
 902
 903         function getEmptyBody() {
 904                 $colspan = count( $this->getFieldNames() );
 905                 $msgEmpty = wfMsgHtml( 'table_pager_empty' );
 906                 return "<tr><td colspan=\"$colspan\">$msgEmpty</td></tr>\n";
 907         }
 908
 909         function formatRow( $row ) {
 910                 $this->mCurrentRow = $row;      # In case formatValue etc need to know
 911                 $s = Xml::openElement( 'tr', $this->getRowAttrs($row) );
 912                 $fieldNames = $this->getFieldNames();
 913                 foreach ( $fieldNames as $field => $name ) {
 914                         $value = isset( $row->$field ) ? $row->$field : null;
 915                         $formatted = strval( $this->formatValue( $field, $value ) );
 916                         if ( $formatted == '' ) {
 917                                 $formatted = '&#160;';
 918                         }
 919                         $s .= Xml::tags( 'td', $this->getCellAttrs( $field, $value ), $formatted );
 920                 }
 921                 $s .= "</tr>\n";
 922                 return $s;
 923         }
 924
 925         /**
 926          * Get a class name to be applied to the given row.
 927          *
 928          * @param $row Object: the database result row
 929          * @return String
 930          */
 931         function getRowClass( $row ) {
 932                 return '';
 933         }
 934
 935         /**
 936          * Get attributes to be applied to the given row.
 937          *
 938          * @param $row Object: the database result row
 939          * @return Associative array
 940          */
 941         function getRowAttrs( $row ) {
 942                 $class = $this->getRowClass( $row );
 943                 if ( $class === '' ) {
 944                         // Return an empty array to avoid clutter in HTML like class=""
 945                         return array();
 946                 } else {
 947                         return array( 'class' => $this->getRowClass( $row ) );
 948                 }
 949         }
 950
 951         /**
 952          * Get any extra attributes to be applied to the given cell. Don't
 953          * take this as an excuse to hardcode styles; use classes and
 954          * CSS instead.  Row context is available in $this->mCurrentRow
 955          *
 956          * @param $field The column
 957          * @param $value The cell contents
 958          * @return Associative array
 959          */
 960         function getCellAttrs( $field, $value ) {
 961                 return array( 'class' => 'TablePager_col_' . $field );
 962         }
 963
 964         function getIndexField() {
 965                 return $this->mSort;
 966         }
 967
 968         function getTableClass() {
 969                 return 'TablePager';
 970         }
 971
 972         function getNavClass() {
 973                 return 'TablePager_nav';
 974         }
 975
 976         function getSortHeaderClass() {
 977                 return 'TablePager_sort';
 978         }
 979
 980         /**
 981          * A navigation bar with images
 982          */
 983         function getNavigationBar() {
 984                 global $wgStylePath, $wgLang;
 985
 986                 if ( !$this->isNavigationBarShown() ) {
 987                         return '';
 988                 }
 989
 990                 $path = "$wgStylePath/common/images";
 991                 $labels = array(
 992                         'first' => 'table_pager_first',
 993                         'prev' => 'table_pager_prev',
 994                         'next' => 'table_pager_next',
 995                         'last' => 'table_pager_last',
 996                 );
 997                 $images = array(
 998                         'first' => 'arrow_first_25.png',
 999                         'prev' => 'arrow_left_25.png',
1000                         'next' => 'arrow_right_25.png',
1001                         'last' => 'arrow_last_25.png',
1002                 );
1003                 $disabledImages = array(
1004                         'first' => 'arrow_disabled_first_25.png',
1005                         'prev' => 'arrow_disabled_left_25.png',
1006                         'next' => 'arrow_disabled_right_25.png',
1007                         'last' => 'arrow_disabled_last_25.png',
1008                 );
1009                 if( $wgLang->isRTL() ) {
1010                         $keys = array_keys( $labels );
1011                         $images = array_combine( $keys, array_reverse( $images ) );
1012                         $disabledImages = array_combine( $keys, array_reverse( $disabledImages ) );
1013                 }
1014
1015                 $linkTexts = array();
1016                 $disabledTexts = array();
1017                 foreach ( $labels as $type => $label ) {
1018                         $msgLabel = wfMsgHtml( $label );
1019                         $linkTexts[$type] = "<img src=\"$path/{$images[$type]}\" alt=\"$msgLabel\"/><br />$msgLabel";
1020                         $disabledTexts[$type] = "<img src=\"$path/{$disabledImages[$type]}\" alt=\"$msgLabel\"/><br />$msgLabel";
1021                 }
1022                 $links = $this->getPagingLinks( $linkTexts, $disabledTexts );
1023
1024                 $navClass = htmlspecialchars( $this->getNavClass() );
1025                 $s = "<table class=\"$navClass\"><tr>\n";
1026                 $width = 100 / count( $links ) . '%';
1027                 foreach ( $labels as $type => $label ) {
1028                         $s .= "<td style='width:$width;'>{$links[$type]}</td>\n";
1029                 }
1030                 $s .= "</tr></table>\n";
1031                 return $s;
1032         }
1033
1034         /**
1035          * Get a <select> element which has options for each of the allowed limits
1036          *
1037          * @return String: HTML fragment
1038          */
1039         function getLimitSelect() {
1040                 global $wgLang;
1041
1042                 # Add the current limit from the query string
1043                 # to avoid that the limit is lost after clicking Go next time
1044                 if ( !in_array( $this->mLimit, $this->mLimitsShown ) ) {
1045                         $this->mLimitsShown[] = $this->mLimit;
1046                         sort( $this->mLimitsShown );
1047                 }
1048                 $s = Html::openElement( 'select', array( 'name' => 'limit' ) ) . "\n";
1049                 foreach ( $this->mLimitsShown as $key => $value ) {
1050                         # The pair is either $index => $limit, in which case the $value
1051                         # will be numeric, or $limit => $text, in which case the $value
1052                         # will be a string.
1053                         if( is_int( $value ) ){
1054                                 $limit = $value;
1055                                 $text = $wgLang->formatNum( $limit );
1056                         } else {
1057                                 $limit = $key;
1058                                 $text = $value;
1059                         }
1060                         $s .= Xml::option( $text, $limit, $limit == $this->mLimit ) . "\n";
1061                 }
1062                 $s .= Html::closeElement( 'select' );
1063                 return $s;
1064         }
1065
1066         /**
1067          * Get <input type="hidden"> elements for use in a method="get" form.
1068          * Resubmits all defined elements of the query string, except for a
1069          * blacklist, passed in the $blacklist parameter.
1070          *
1071          * @return String: HTML fragment
1072          */
1073         function getHiddenFields( $blacklist = array() ) {
1074                 global $wgRequest;
1075
1076                 $blacklist = (array)$blacklist;
1077                 $query = $wgRequest->getQueryValues();
1078                 foreach ( $blacklist as $name ) {
1079                         unset( $query[$name] );
1080                 }
1081                 $s = '';
1082                 foreach ( $query as $name => $value ) {
1083                         $encName = htmlspecialchars( $name );
1084                         $encValue = htmlspecialchars( $value );
1085                         $s .= "<input type=\"hidden\" name=\"$encName\" value=\"$encValue\"/>\n";
1086                 }
1087                 return $s;
1088         }
1089
1090         /**
1091          * Get a form containing a limit selection dropdown
1092          *
1093          * @return String: HTML fragment
1094          */
1095         function getLimitForm() {
1096                 global $wgScript;
1097
1098                 return Xml::openElement(
1099                         'form',
1100                         array(
1101                                 'method' => 'get',
1102                                 'action' => $wgScript
1103                         ) ) . "\n" . $this->getLimitDropdown() . "</form>\n";
1104         }
1105
1106         /**
1107          * Gets a limit selection dropdown
1108          *
1109          * @return string
1110          */
1111         function getLimitDropdown() {
1112                 # Make the select with some explanatory text
1113                 $msgSubmit = wfMsgHtml( 'table_pager_limit_submit' );
1114
1115                 return wfMsgHtml( 'table_pager_limit', $this->getLimitSelect() ) .
1116                         "\n<input type=\"submit\" value=\"$msgSubmit\"/>\n" .
1117                         $this->getHiddenFields( array( 'limit' ) );
1118         }
1119
1120         /**
1121          * Return true if the named field should be sortable by the UI, false
1122          * otherwise
1123          *
1124          * @param $field String
1125          */
1126         abstract function isFieldSortable( $field );
1127
1128         /**
1129          * Format a table cell. The return value should be HTML, but use an empty
1130          * string not &#160; for empty cells. Do not include the <td> and </td>.
1131          *
1132          * The current result row is available as $this->mCurrentRow, in case you
1133          * need more context.
1134          *
1135          * @param $name String: the database field name
1136          * @param $value String: the value retrieved from the database
1137          */
1138         abstract function formatValue( $name, $value );
1139
1140         /**
1141          * The database field name used as a default sort order
1142          */
1143         abstract function getDefaultSort();
1144
1145         /**
1146          * An array mapping database field names to a textual description of the
1147          * field name, for use in the table header. The description should be plain
1148          * text, it will be HTML-escaped later.
1149          */
1150         abstract function getFieldNames();
1151 }