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(); // column to sort on
 123                 $extraSort = $this->getExtraSortFields(); // extra columns to sort on for query planning
 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 = isset( $extraSort[$order] )
 129                                 ? (array)$extraSort[$order]
 130                                 : array();
 131                 } elseif( is_array( $index ) ) {
 132                         # First element is the default
 133                         reset( $index );
 134                         list( $this->mOrderType, $this->mIndexField ) = each( $index );
 135                         $this->mExtraSortFields = isset( $extraSort[$this->mOrderType] )
 136                                 ? (array)$extraSort[$this->mOrderType]
 137                                 : array();
 138                 } else {
 139                         # $index is not an array
 140                         $this->mOrderType = null;
 141                         $this->mIndexField = $index;
 142                         $this->mExtraSortFields = (array)$extraSort;
 143                 }
 144
 145                 if( !isset( $this->mDefaultDirection ) ) {
 146                         $dir = $this->getDefaultDirections();
 147                         $this->mDefaultDirection = is_array( $dir )
 148                                 ? $dir[$this->mOrderType]
 149                                 : $dir;
 150                 }
 151         }
 152
 153         /**
 154          * Do the query, using information from the object context. This function
 155          * has been kept minimal to make it overridable if necessary, to allow for
 156          * result sets formed from multiple DB queries.
 157          */
 158         public function doQuery() {
 159                 # Use the child class name for profiling
 160                 $fname = __METHOD__ . ' (' . get_class( $this ) . ')';
 161                 wfProfileIn( $fname );
 162
 163                 $descending = ( $this->mIsBackwards == $this->mDefaultDirection );
 164                 # Plus an extra row so that we can tell the "next" link should be shown
 165                 $queryLimit = $this->mLimit + 1;
 166
 167                 $this->mResult = $this->reallyDoQuery(
 168                         $this->mOffset,
 169                         $queryLimit,
 170                         $descending
 171                 );
 172                 $this->extractResultInfo( $this->mOffset, $queryLimit, $this->mResult );
 173                 $this->mQueryDone = true;
 174
 175                 $this->preprocessResults( $this->mResult );
 176                 $this->mResult->rewind(); // Paranoia
 177
 178                 wfProfileOut( $fname );
 179         }
 180
 181         /**
 182          * @return ResultWrapper The result wrapper.
 183          */
 184         function getResult() {
 185                 return $this->mResult;
 186         }
 187
 188         /**
 189          * Set the offset from an other source than $wgRequest
 190          */
 191         function setOffset( $offset ) {
 192                 $this->mOffset = $offset;
 193         }
 194         /**
 195          * Set the limit from an other source than $wgRequest
 196          */
 197         function setLimit( $limit ) {
 198                 $this->mLimit = $limit;
 199         }
 200
 201         /**
 202          * Extract some useful data from the result object for use by
 203          * the navigation bar, put it into $this
 204          *
 205          * @param $offset String: index offset, inclusive
 206          * @param $limit Integer: exact query limit
 207          * @param $res ResultWrapper
 208          */
 209         function extractResultInfo( $offset, $limit, ResultWrapper $res ) {
 210                 $numRows = $res->numRows();
 211                 if ( $numRows ) {
 212                         # Remove any table prefix from index field
 213                         $parts = explode( '.', $this->mIndexField );
 214                         $indexColumn = end( $parts );
 215
 216                         $row = $res->fetchRow();
 217                         $firstIndex = $row[$indexColumn];
 218
 219                         # Discard the extra result row if there is one
 220                         if ( $numRows > $this->mLimit && $numRows > 1 ) {
 221                                 $res->seek( $numRows - 1 );
 222                                 $this->mPastTheEndRow = $res->fetchObject();
 223                                 $indexField = $this->mIndexField;
 224                                 $this->mPastTheEndIndex = $this->mPastTheEndRow->$indexField;
 225                                 $res->seek( $numRows - 2 );
 226                                 $row = $res->fetchRow();
 227                                 $lastIndex = $row[$indexColumn];
 228                         } else {
 229                                 $this->mPastTheEndRow = null;
 230                                 # Setting indexes to an empty string means that they will be
 231                                 # omitted if they would otherwise appear in URLs. It just so
 232                                 # happens that this  is the right thing to do in the standard
 233                                 # UI, in all the relevant cases.
 234                                 $this->mPastTheEndIndex = '';
 235                                 $res->seek( $numRows - 1 );
 236                                 $row = $res->fetchRow();
 237                                 $lastIndex = $row[$indexColumn];
 238                         }
 239                 } else {
 240                         $firstIndex = '';
 241                         $lastIndex = '';
 242                         $this->mPastTheEndRow = null;
 243                         $this->mPastTheEndIndex = '';
 244                 }
 245
 246                 if ( $this->mIsBackwards ) {
 247                         $this->mIsFirst = ( $numRows < $limit );
 248                         $this->mIsLast = ( $offset == '' );
 249                         $this->mLastShown = $firstIndex;
 250                         $this->mFirstShown = $lastIndex;
 251                 } else {
 252                         $this->mIsFirst = ( $offset == '' );
 253                         $this->mIsLast = ( $numRows < $limit );
 254                         $this->mLastShown = $lastIndex;
 255                         $this->mFirstShown = $firstIndex;
 256                 }
 257         }
 258
 259         /**
 260          * Get some text to go in brackets in the "function name" part of the SQL comment
 261          *
 262          * @return String
 263          */
 264         function getSqlComment() {
 265                 return get_class( $this );
 266         }
 267
 268         /**
 269          * Do a query with specified parameters, rather than using the object
 270          * context
 271          *
 272          * @param $offset String: index offset, inclusive
 273          * @param $limit Integer: exact query limit
 274          * @param $descending Boolean: query direction, false for ascending, true for descending
 275          * @return ResultWrapper
 276          */
 277         function reallyDoQuery( $offset, $limit, $descending ) {
 278                 $fname = __METHOD__ . ' (' . $this->getSqlComment() . ')';
 279                 $info = $this->getQueryInfo();
 280                 $tables = $info['tables'];
 281                 $fields = $info['fields'];
 282                 $conds = isset( $info['conds'] ) ? $info['conds'] : array();
 283                 $options = isset( $info['options'] ) ? $info['options'] : array();
 284                 $join_conds = isset( $info['join_conds'] ) ? $info['join_conds'] : array();
 285                 $sortColumns = array_merge( array( $this->mIndexField ), $this->mExtraSortFields );
 286                 if ( $descending ) {
 287                         $options['ORDER BY'] = implode( ',', $sortColumns );
 288                         $operator = '>';
 289                 } else {
 290                         $orderBy = array();
 291                         foreach ( $sortColumns as $col ) {
 292                                 $orderBy[] = $col . ' DESC';
 293                         }
 294                         $options['ORDER BY'] = implode( ',', $orderBy );
 295                         $operator = '<';
 296                 }
 297                 if ( $offset != '' ) {
 298                         $conds[] = $this->mIndexField . $operator . $this->mDb->addQuotes( $offset );
 299                 }
 300                 $options['LIMIT'] = intval( $limit );
 301                 $res = $this->mDb->select( $tables, $fields, $conds, $fname, $options, $join_conds );
 302                 return new ResultWrapper( $this->mDb, $res );
 303         }
 304
 305         /**
 306          * Pre-process results; useful for performing batch existence checks, etc.
 307          *
 308          * @param $result ResultWrapper
 309          */
 310         protected function preprocessResults( $result ) {}
 311
 312         /**
 313          * Get the formatted result list. Calls getStartBody(), formatRow() and
 314          * getEndBody(), concatenates the results and returns them.
 315          *
 316          * @return String
 317          */
 318         function getBody() {
 319                 if ( !$this->mQueryDone ) {
 320                         $this->doQuery();
 321                 }
 322                 # Don't use any extra rows returned by the query
 323                 $numRows = min( $this->mResult->numRows(), $this->mLimit );
 324
 325                 $s = $this->getStartBody();
 326                 if ( $numRows ) {
 327                         if ( $this->mIsBackwards ) {
 328                                 for ( $i = $numRows - 1; $i >= 0; $i-- ) {
 329                                         $this->mResult->seek( $i );
 330                                         $row = $this->mResult->fetchObject();
 331                                         $s .= $this->formatRow( $row );
 332                                 }
 333                         } else {
 334                                 $this->mResult->seek( 0 );
 335                                 for ( $i = 0; $i < $numRows; $i++ ) {
 336                                         $row = $this->mResult->fetchObject();
 337                                         $s .= $this->formatRow( $row );
 338                                 }
 339                         }
 340                 } else {
 341                         $s .= $this->getEmptyBody();
 342                 }
 343                 $s .= $this->getEndBody();
 344                 return $s;
 345         }
 346
 347         /**
 348          * Make a self-link
 349          *
 350          * @param $text String: text displayed on the link
 351          * @param $query Array: associative array of paramter to be in the query string
 352          * @param $type String: value of the "rel" attribute
 353          * @return String: HTML fragment
 354          */
 355         function makeLink($text, $query = null, $type=null) {
 356                 if ( $query === null ) {
 357                         return $text;
 358                 }
 359
 360                 $attrs = array();
 361                 if( in_array( $type, array( 'first', 'prev', 'next', 'last' ) ) ) {
 362                         # HTML5 rel attributes
 363                         $attrs['rel'] = $type;
 364                 }
 365
 366                 if( $type ) {
 367                         $attrs['class'] = "mw-{$type}link";
 368                 }
 369                 return $this->getSkin()->link(
 370                         $this->getTitle(),
 371                         $text,
 372                         $attrs,
 373                         $query + $this->getDefaultQuery(),
 374                         array( 'noclasses', 'known' )
 375                 );
 376         }
 377
 378         /**
 379          * Hook into getBody(), allows text to be inserted at the start. This
 380          * will be called even if there are no rows in the result set.
 381          *
 382          * @return String
 383          */
 384         function getStartBody() {
 385                 return '';
 386         }
 387
 388         /**
 389          * Hook into getBody() for the end of the list
 390          *
 391          * @return String
 392          */
 393         function getEndBody() {
 394                 return '';
 395         }
 396
 397         /**
 398          * Hook into getBody(), for the bit between the start and the
 399          * end when there are no rows
 400          *
 401          * @return String
 402          */
 403         function getEmptyBody() {
 404                 return '';
 405         }
 406
 407         /**
 408          * Title used for self-links. Override this if you want to be able to
 409          * use a title other than $wgTitle
 410          *
 411          * @return Title object
 412          */
 413         function getTitle() {
 414                 return $GLOBALS['wgTitle'];
 415         }
 416
 417         /**
 418          * Get the current skin. This can be overridden if necessary.
 419          *
 420          * @return Skin object
 421          */
 422         function getSkin() {
 423                 if ( !isset( $this->mSkin ) ) {
 424                         global $wgUser;
 425                         $this->mSkin = $wgUser->getSkin();
 426                 }
 427                 return $this->mSkin;
 428         }
 429
 430         /**
 431          * Get an array of query parameters that should be put into self-links.
 432          * By default, all parameters passed in the URL are used, except for a
 433          * short blacklist.
 434          *
 435          * @return Associative array
 436          */
 437         function getDefaultQuery() {
 438                 global $wgRequest;
 439
 440                 if ( !isset( $this->mDefaultQuery ) ) {
 441                         $this->mDefaultQuery = $wgRequest->getQueryValues();
 442                         unset( $this->mDefaultQuery['title'] );
 443                         unset( $this->mDefaultQuery['dir'] );
 444                         unset( $this->mDefaultQuery['offset'] );
 445                         unset( $this->mDefaultQuery['limit'] );
 446                         unset( $this->mDefaultQuery['order'] );
 447                         unset( $this->mDefaultQuery['month'] );
 448                         unset( $this->mDefaultQuery['year'] );
 449                 }
 450                 return $this->mDefaultQuery;
 451         }
 452
 453         /**
 454          * Get the number of rows in the result set
 455          *
 456          * @return Integer
 457          */
 458         function getNumRows() {
 459                 if ( !$this->mQueryDone ) {
 460                         $this->doQuery();
 461                 }
 462                 return $this->mResult->numRows();
 463         }
 464
 465         /**
 466          * Get a URL query array for the prev, next, first and last links.
 467          *
 468          * @return Array
 469          */
 470         function getPagingQueries() {
 471                 if ( !$this->mQueryDone ) {
 472                         $this->doQuery();
 473                 }
 474
 475                 # Don't announce the limit everywhere if it's the default
 476                 $urlLimit = $this->mLimit == $this->mDefaultLimit ? '' : $this->mLimit;
 477
 478                 if ( $this->mIsFirst ) {
 479                         $prev = false;
 480                         $first = false;
 481                 } else {
 482                         $prev = array(
 483                                 'dir' => 'prev',
 484                                 'offset' => $this->mFirstShown,
 485                                 'limit' => $urlLimit
 486                         );
 487                         $first = array( 'limit' => $urlLimit );
 488                 }
 489                 if ( $this->mIsLast ) {
 490                         $next = false;
 491                         $last = false;
 492                 } else {
 493                         $next = array( 'offset' => $this->mLastShown, 'limit' => $urlLimit );
 494                         $last = array( 'dir' => 'prev', 'limit' => $urlLimit );
 495                 }
 496                 return array(
 497                         'prev' => $prev,
 498                         'next' => $next,
 499                         'first' => $first,
 500                         'last' => $last
 501                 );
 502         }
 503
 504         /**
 505          * Returns whether to show the "navigation bar"
 506          *
 507          * @return Boolean
 508          */
 509         function isNavigationBarShown() {
 510                 if ( !$this->mQueryDone ) {
 511                         $this->doQuery();
 512                 }
 513                 // Hide navigation by default if there is nothing to page
 514                 return !($this->mIsFirst && $this->mIsLast);
 515         }
 516
 517         /**
 518          * Get paging links. If a link is disabled, the item from $disabledTexts
 519          * will be used. If there is no such item, the unlinked text from
 520          * $linkTexts will be used. Both $linkTexts and $disabledTexts are arrays
 521          * of HTML.
 522          *
 523          * @return Array
 524          */
 525         function getPagingLinks( $linkTexts, $disabledTexts = array() ) {
 526                 $queries = $this->getPagingQueries();
 527                 $links = array();
 528                 foreach ( $queries as $type => $query ) {
 529                         if ( $query !== false ) {
 530                                 $links[$type] = $this->makeLink(
 531                                         $linkTexts[$type],
 532                                         $queries[$type],
 533                                         $type
 534                                 );
 535                         } elseif ( isset( $disabledTexts[$type] ) ) {
 536                                 $links[$type] = $disabledTexts[$type];
 537                         } else {
 538                                 $links[$type] = $linkTexts[$type];
 539                         }
 540                 }
 541                 return $links;
 542         }
 543
 544         function getLimitLinks() {
 545                 global $wgLang;
 546                 $links = array();
 547                 if ( $this->mIsBackwards ) {
 548                         $offset = $this->mPastTheEndIndex;
 549                 } else {
 550                         $offset = $this->mOffset;
 551                 }
 552                 foreach ( $this->mLimitsShown as $limit ) {
 553                         $links[] = $this->makeLink(
 554                                 $wgLang->formatNum( $limit ),
 555                                 array( 'offset' => $offset, 'limit' => $limit ),
 556                                 'num'
 557                         );
 558                 }
 559                 return $links;
 560         }
 561
 562         /**
 563          * Abstract formatting function. This should return an HTML string
 564          * representing the result row $row. Rows will be concatenated and
 565          * returned by getBody()
 566          *
 567          * @param $row Object: database row
 568          * @return String
 569          */
 570         abstract function formatRow( $row );
 571
 572         /**
 573          * This function should be overridden to provide all parameters
 574          * needed for the main paged query. It returns an associative
 575          * array with the following elements:
 576          *    tables => Table(s) for passing to Database::select()
 577          *    fields => Field(s) for passing to Database::select(), may be *
 578          *    conds => WHERE conditions
 579          *    options => option array
 580          *    join_conds => JOIN conditions
 581          *
 582          * @return Array
 583          */
 584         abstract function getQueryInfo();
 585
 586         /**
 587          * This function should be overridden to return the name of the index fi-
 588          * eld.  If the pager supports multiple orders, it may return an array of
 589          * 'querykey' => 'indexfield' pairs, so that a request with &count=querykey
 590          * will use indexfield to sort.  In this case, the first returned key is
 591          * the default.
 592          *
 593          * Needless to say, it's really not a good idea to use a non-unique index
 594          * for this!  That won't page right.
 595          *
 596          * @return string|Array
 597          */
 598         abstract function getIndexField();
 599
 600         /**
 601          * This function should be overridden to return the names of secondary columns
 602          * to order by in addition to the column in getIndexField(). These fields will
 603          * not be used in the pager offset or in any links for users.
 604          *
 605          * If getIndexField() returns an array of 'querykey' => 'indexfield' pairs then
 606          * this must return a corresponding array of 'querykey' => array( fields...) pairs
 607          * in order for a request with &count=querykey to use array( fields...) to sort.
 608          *
 609          * This is useful for pagers that GROUP BY a unique column (say page_id)
 610          * and ORDER BY another (say page_len). Using GROUP BY and ORDER BY both on
 611          * page_len,page_id avoids temp tables (given a page_len index). This would
 612          * also work if page_id was non-unique but we had a page_len,page_id index.
 613          *
 614          * @return Array
 615          */
 616         protected function getExtraSortFields() { return array(); }
 617
 618         /**
 619          * Return the default sorting direction: false for ascending, true for de-
 620          * scending.  You can also have an associative array of ordertype => dir,
 621          * if multiple order types are supported.  In this case getIndexField()
 622          * must return an array, and the keys of that must exactly match the keys
 623          * of this.
 624          *
 625          * For backward compatibility, this method's return value will be ignored
 626          * if $this->mDefaultDirection is already set when the constructor is
 627          * called, for instance if it's statically initialized.  In that case the
 628          * value of that variable (which must be a boolean) will be used.
 629          *
 630          * Note that despite its name, this does not return the value of the
 631          * $this->mDefaultDirection member variable.  That's the default for this
 632          * particular instantiation, which is a single value.  This is the set of
 633          * all defaults for the class.
 634          *
 635          * @return Boolean
 636          */
 637         protected function getDefaultDirections() { return false; }
 638 }
 639
 640
 641 /**
 642  * IndexPager with an alphabetic list and a formatted navigation bar
 643  * @ingroup Pager
 644  */
 645 abstract class AlphabeticPager extends IndexPager {
 646         /**
 647          * Shamelessly stolen bits from ReverseChronologicalPager,
 648          * didn't want to do class magic as may be still revamped
 649          */
 650         function getNavigationBar() {
 651                 global $wgLang;
 652
 653                 if ( !$this->isNavigationBarShown() ) return '';
 654
 655                 if( isset( $this->mNavigationBar ) ) {
 656                         return $this->mNavigationBar;
 657                 }
 658
 659                 $opts = array( 'parsemag', 'escapenoentities' );
 660                 $linkTexts = array(
 661                         'prev' => wfMsgExt(
 662                                 'prevn',
 663                                 $opts,
 664                                 $wgLang->formatNum( $this->mLimit )
 665                         ),
 666                         'next' => wfMsgExt(
 667                                 'nextn',
 668                                 $opts,
 669                                 $wgLang->formatNum($this->mLimit )
 670                         ),
 671                         'first' => wfMsgExt( 'page_first', $opts ),
 672                         'last' => wfMsgExt( 'page_last', $opts )
 673                 );
 674
 675                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 676                 $limitLinks = $this->getLimitLinks();
 677                 $limits = $wgLang->pipeList( $limitLinks );
 678
 679                 $this->mNavigationBar =
 680                         "(" . $wgLang->pipeList(
 681                                 array( $pagingLinks['first'],
 682                                 $pagingLinks['last'] )
 683                         ) . ") " .
 684                         wfMsgHtml( 'viewprevnext', $pagingLinks['prev'],
 685                         $pagingLinks['next'], $limits );
 686
 687                 if( !is_array( $this->getIndexField() ) ) {
 688                         # Early return to avoid undue nesting
 689                         return $this->mNavigationBar;
 690                 }
 691
 692                 $extra = '';
 693                 $first = true;
 694                 $msgs = $this->getOrderTypeMessages();
 695                 foreach( array_keys( $msgs ) as $order ) {
 696                         if( $first ) {
 697                                 $first = false;
 698                         } else {
 699                                 $extra .= wfMsgExt( 'pipe-separator' , 'escapenoentities' );
 700                         }
 701
 702                         if( $order == $this->mOrderType ) {
 703                                 $extra .= wfMsgHTML( $msgs[$order] );
 704                         } else {
 705                                 $extra .= $this->makeLink(
 706                                         wfMsgHTML( $msgs[$order] ),
 707                                         array( 'order' => $order )
 708                                 );
 709                         }
 710                 }
 711
 712                 if( $extra !== '' ) {
 713                         $this->mNavigationBar .= " ($extra)";
 714                 }
 715
 716                 return $this->mNavigationBar;
 717         }
 718
 719         /**
 720          * If this supports multiple order type messages, give the message key for
 721          * enabling each one in getNavigationBar.  The return type is an associa-
 722          * tive array whose keys must exactly match the keys of the array returned
 723          * by getIndexField(), and whose values are message keys.
 724          *
 725          * @return Array
 726          */
 727         protected function getOrderTypeMessages() {
 728                 return null;
 729         }
 730 }
 731
 732 /**
 733  * IndexPager with a formatted navigation bar
 734  * @ingroup Pager
 735  */
 736 abstract class ReverseChronologicalPager extends IndexPager {
 737         public $mDefaultDirection = true;
 738         public $mYear;
 739         public $mMonth;
 740
 741         function __construct() {
 742                 parent::__construct();
 743         }
 744
 745         function getNavigationBar() {
 746                 global $wgLang;
 747
 748                 if ( !$this->isNavigationBarShown() ) {
 749                         return '';
 750                 }
 751
 752                 if ( isset( $this->mNavigationBar ) ) {
 753                         return $this->mNavigationBar;
 754                 }
 755                 $nicenumber = $wgLang->formatNum( $this->mLimit );
 756                 $linkTexts = array(
 757                         'prev' => wfMsgExt(
 758                                 'pager-newer-n',
 759                                 array( 'parsemag', 'escape' ),
 760                                 $nicenumber
 761                         ),
 762                         'next' => wfMsgExt(
 763                                 'pager-older-n',
 764                                 array( 'parsemag', 'escape' ),
 765                                 $nicenumber
 766                         ),
 767                         'first' => wfMsgHtml( 'histlast' ),
 768                         'last' => wfMsgHtml( 'histfirst' )
 769                 );
 770
 771                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 772                 $limitLinks = $this->getLimitLinks();
 773                 $limits = $wgLang->pipeList( $limitLinks );
 774
 775                 $this->mNavigationBar = "({$pagingLinks['first']}" .
 776                         wfMsgExt( 'pipe-separator' , 'escapenoentities' ) .
 777                         "{$pagingLinks['last']}) " .
 778                         wfMsgHTML(
 779                                 'viewprevnext',
 780                                 $pagingLinks['prev'], $pagingLinks['next'],
 781                                 $limits
 782                         );
 783                 return $this->mNavigationBar;
 784         }
 785
 786         function getDateCond( $year, $month ) {
 787                 $year = intval($year);
 788                 $month = intval($month);
 789                 // Basic validity checks
 790                 $this->mYear = $year > 0 ? $year : false;
 791                 $this->mMonth = ($month > 0 && $month < 13) ? $month : false;
 792                 // Given an optional year and month, we need to generate a timestamp
 793                 // to use as "WHERE rev_timestamp <= result"
 794                 // Examples: year = 2006 equals < 20070101 (+000000)
 795                 // year=2005, month=1    equals < 20050201
 796                 // year=2005, month=12   equals < 20060101
 797                 if ( !$this->mYear && !$this->mMonth ) {
 798                         return;
 799                 }
 800                 if ( $this->mYear ) {
 801                         $year = $this->mYear;
 802                 } else {
 803                         // If no year given, assume the current one
 804                         $year = gmdate( 'Y' );
 805                         // If this month hasn't happened yet this year, go back to last year's month
 806                         if( $this->mMonth > gmdate( 'n' ) ) {
 807                                 $year--;
 808                         }
 809                 }
 810                 if ( $this->mMonth ) {
 811                         $month = $this->mMonth + 1;
 812                         // For December, we want January 1 of the next year
 813                         if ($month > 12) {
 814                                 $month = 1;
 815                                 $year++;
 816                         }
 817                 } else {
 818                         // No month implies we want up to the end of the year in question
 819                         $month = 1;
 820                         $year++;
 821                 }
 822                 // Y2K38 bug
 823                 if ( $year > 2032 ) {
 824                         $year = 2032;
 825                 }
 826                 $ymd = (int)sprintf( "%04d%02d01", $year, $month );
 827                 if ( $ymd > 20320101 ) {
 828                         $ymd = 20320101;
 829                 }
 830                 $this->mOffset = $this->mDb->timestamp( "${ymd}000000" );
 831         }
 832 }
 833
 834 /**
 835  * Table-based display with a user-selectable sort order
 836  * @ingroup Pager
 837  */
 838 abstract class TablePager extends IndexPager {
 839         var $mSort;
 840         var $mCurrentRow;
 841
 842         function __construct() {
 843                 global $wgRequest;
 844                 $this->mSort = $wgRequest->getText( 'sort' );
 845                 if ( !array_key_exists( $this->mSort, $this->getFieldNames() ) ) {
 846                         $this->mSort = $this->getDefaultSort();
 847                 }
 848                 if ( $wgRequest->getBool( 'asc' ) ) {
 849                         $this->mDefaultDirection = false;
 850                 } elseif ( $wgRequest->getBool( 'desc' ) ) {
 851                         $this->mDefaultDirection = true;
 852                 } /* Else leave it at whatever the class default is */
 853
 854                 parent::__construct();
 855         }
 856
 857         function getStartBody() {
 858                 global $wgStylePath;
 859                 $tableClass = htmlspecialchars( $this->getTableClass() );
 860                 $sortClass = htmlspecialchars( $this->getSortHeaderClass() );
 861
 862                 $s = "<table style='border:1;' class=\"mw-datatable $tableClass\"><thead><tr>\n";
 863                 $fields = $this->getFieldNames();
 864
 865                 # Make table header
 866                 foreach ( $fields as $field => $name ) {
 867                         if ( strval( $name ) == '' ) {
 868                                 $s .= "<th>&#160;</th>\n";
 869                         } elseif ( $this->isFieldSortable( $field ) ) {
 870                                 $query = array( 'sort' => $field, 'limit' => $this->mLimit );
 871                                 if ( $field == $this->mSort ) {
 872                                         # This is the sorted column
 873                                         # Prepare a link that goes in the other sort order
 874                                         if ( $this->mDefaultDirection ) {
 875                                                 # Descending
 876                                                 $image = 'Arr_d.png';
 877                                                 $query['asc'] = '1';
 878                                                 $query['desc'] = '';
 879                                                 $alt = htmlspecialchars( wfMsg( 'descending_abbrev' ) );
 880                                         } else {
 881                                                 # Ascending
 882                                                 $image = 'Arr_u.png';
 883                                                 $query['asc'] = '';
 884                                                 $query['desc'] = '1';
 885                                                 $alt = htmlspecialchars( wfMsg( 'ascending_abbrev' ) );
 886                                         }
 887                                         $image = htmlspecialchars( "$wgStylePath/common/images/$image" );
 888                                         $link = $this->makeLink(
 889                                                 "<img width=\"12\" height=\"12\" alt=\"$alt\" src=\"$image\" />" .
 890                                                 htmlspecialchars( $name ), $query );
 891                                         $s .= "<th class=\"$sortClass\">$link</th>\n";
 892                                 } else {
 893                                         $s .= '<th>' . $this->makeLink( htmlspecialchars( $name ), $query ) . "</th>\n";
 894                                 }
 895                         } else {
 896                                 $s .= '<th>' . htmlspecialchars( $name ) . "</th>\n";
 897                         }
 898                 }
 899                 $s .= "</tr></thead><tbody>\n";
 900                 return $s;
 901         }
 902
 903         function getEndBody() {
 904                 return "</tbody></table>\n";
 905         }
 906
 907         function getEmptyBody() {
 908                 $colspan = count( $this->getFieldNames() );
 909                 $msgEmpty = wfMsgHtml( 'table_pager_empty' );
 910                 return "<tr><td colspan=\"$colspan\">$msgEmpty</td></tr>\n";
 911         }
 912
 913         function formatRow( $row ) {
 914                 $this->mCurrentRow = $row;      # In case formatValue etc need to know
 915                 $s = Xml::openElement( 'tr', $this->getRowAttrs($row) );
 916                 $fieldNames = $this->getFieldNames();
 917                 foreach ( $fieldNames as $field => $name ) {
 918                         $value = isset( $row->$field ) ? $row->$field : null;
 919                         $formatted = strval( $this->formatValue( $field, $value ) );
 920                         if ( $formatted == '' ) {
 921                                 $formatted = '&#160;';
 922                         }
 923                         $s .= Xml::tags( 'td', $this->getCellAttrs( $field, $value ), $formatted );
 924                 }
 925                 $s .= "</tr>\n";
 926                 return $s;
 927         }
 928
 929         /**
 930          * Get a class name to be applied to the given row.
 931          *
 932          * @param $row Object: the database result row
 933          * @return String
 934          */
 935         function getRowClass( $row ) {
 936                 return '';
 937         }
 938
 939         /**
 940          * Get attributes to be applied to the given row.
 941          *
 942          * @param $row Object: the database result row
 943          * @return Associative array
 944          */
 945         function getRowAttrs( $row ) {
 946                 $class = $this->getRowClass( $row );
 947                 if ( $class === '' ) {
 948                         // Return an empty array to avoid clutter in HTML like class=""
 949                         return array();
 950                 } else {
 951                         return array( 'class' => $this->getRowClass( $row ) );
 952                 }
 953         }
 954
 955         /**
 956          * Get any extra attributes to be applied to the given cell. Don't
 957          * take this as an excuse to hardcode styles; use classes and
 958          * CSS instead.  Row context is available in $this->mCurrentRow
 959          *
 960          * @param $field The column
 961          * @param $value The cell contents
 962          * @return Associative array
 963          */
 964         function getCellAttrs( $field, $value ) {
 965                 return array( 'class' => 'TablePager_col_' . $field );
 966         }
 967
 968         function getIndexField() {
 969                 return $this->mSort;
 970         }
 971
 972         function getTableClass() {
 973                 return 'TablePager';
 974         }
 975
 976         function getNavClass() {
 977                 return 'TablePager_nav';
 978         }
 979
 980         function getSortHeaderClass() {
 981                 return 'TablePager_sort';
 982         }
 983
 984         /**
 985          * A navigation bar with images
 986          */
 987         function getNavigationBar() {
 988                 global $wgStylePath, $wgLang;
 989
 990                 if ( !$this->isNavigationBarShown() ) {
 991                         return '';
 992                 }
 993
 994                 $path = "$wgStylePath/common/images";
 995                 $labels = array(
 996                         'first' => 'table_pager_first',
 997                         'prev' => 'table_pager_prev',
 998                         'next' => 'table_pager_next',
 999                         'last' => 'table_pager_last',
1000                 );
1001                 $images = array(
1002                         'first' => 'arrow_first_25.png',
1003                         'prev' => 'arrow_left_25.png',
1004                         'next' => 'arrow_right_25.png',
1005                         'last' => 'arrow_last_25.png',
1006                 );
1007                 $disabledImages = array(
1008                         'first' => 'arrow_disabled_first_25.png',
1009                         'prev' => 'arrow_disabled_left_25.png',
1010                         'next' => 'arrow_disabled_right_25.png',
1011                         'last' => 'arrow_disabled_last_25.png',
1012                 );
1013                 if( $wgLang->isRTL() ) {
1014                         $keys = array_keys( $labels );
1015                         $images = array_combine( $keys, array_reverse( $images ) );
1016                         $disabledImages = array_combine( $keys, array_reverse( $disabledImages ) );
1017                 }
1018
1019                 $linkTexts = array();
1020                 $disabledTexts = array();
1021                 foreach ( $labels as $type => $label ) {
1022                         $msgLabel = wfMsgHtml( $label );
1023                         $linkTexts[$type] = "<img src=\"$path/{$images[$type]}\" alt=\"$msgLabel\"/><br />$msgLabel";
1024                         $disabledTexts[$type] = "<img src=\"$path/{$disabledImages[$type]}\" alt=\"$msgLabel\"/><br />$msgLabel";
1025                 }
1026                 $links = $this->getPagingLinks( $linkTexts, $disabledTexts );
1027
1028                 $navClass = htmlspecialchars( $this->getNavClass() );
1029                 $s = "<table class=\"$navClass\"><tr>\n";
1030                 $width = 100 / count( $links ) . '%';
1031                 foreach ( $labels as $type => $label ) {
1032                         $s .= "<td style='width:$width;'>{$links[$type]}</td>\n";
1033                 }
1034                 $s .= "</tr></table>\n";
1035                 return $s;
1036         }
1037
1038         /**
1039          * Get a <select> element which has options for each of the allowed limits
1040          *
1041          * @return String: HTML fragment
1042          */
1043         function getLimitSelect() {
1044                 global $wgLang;
1045
1046                 # Add the current limit from the query string
1047                 # to avoid that the limit is lost after clicking Go next time
1048                 if ( !in_array( $this->mLimit, $this->mLimitsShown ) ) {
1049                         $this->mLimitsShown[] = $this->mLimit;
1050                         sort( $this->mLimitsShown );
1051                 }
1052                 $s = Html::openElement( 'select', array( 'name' => 'limit' ) ) . "\n";
1053                 foreach ( $this->mLimitsShown as $key => $value ) {
1054                         # The pair is either $index => $limit, in which case the $value
1055                         # will be numeric, or $limit => $text, in which case the $value
1056                         # will be a string.
1057                         if( is_int( $value ) ){
1058                                 $limit = $value;
1059                                 $text = $wgLang->formatNum( $limit );
1060                         } else {
1061                                 $limit = $key;
1062                                 $text = $value;
1063                         }
1064                         $s .= Xml::option( $text, $limit, $limit == $this->mLimit ) . "\n";
1065                 }
1066                 $s .= Html::closeElement( 'select' );
1067                 return $s;
1068         }
1069
1070         /**
1071          * Get <input type="hidden"> elements for use in a method="get" form.
1072          * Resubmits all defined elements of the query string, except for a
1073          * blacklist, passed in the $blacklist parameter.
1074          *
1075          * @return String: HTML fragment
1076          */
1077         function getHiddenFields( $blacklist = array() ) {
1078                 global $wgRequest;
1079
1080                 $blacklist = (array)$blacklist;
1081                 $query = $wgRequest->getQueryValues();
1082                 foreach ( $blacklist as $name ) {
1083                         unset( $query[$name] );
1084                 }
1085                 $s = '';
1086                 foreach ( $query as $name => $value ) {
1087                         $encName = htmlspecialchars( $name );
1088                         $encValue = htmlspecialchars( $value );
1089                         $s .= "<input type=\"hidden\" name=\"$encName\" value=\"$encValue\"/>\n";
1090                 }
1091                 return $s;
1092         }
1093
1094         /**
1095          * Get a form containing a limit selection dropdown
1096          *
1097          * @return String: HTML fragment
1098          */
1099         function getLimitForm() {
1100                 global $wgScript;
1101
1102                 return Xml::openElement(
1103                         'form',
1104                         array(
1105                                 'method' => 'get',
1106                                 'action' => $wgScript
1107                         ) ) . "\n" . $this->getLimitDropdown() . "</form>\n";
1108         }
1109
1110         /**
1111          * Gets a limit selection dropdown
1112          *
1113          * @return string
1114          */
1115         function getLimitDropdown() {
1116                 # Make the select with some explanatory text
1117                 $msgSubmit = wfMsgHtml( 'table_pager_limit_submit' );
1118
1119                 return wfMsgHtml( 'table_pager_limit', $this->getLimitSelect() ) .
1120                         "\n<input type=\"submit\" value=\"$msgSubmit\"/>\n" .
1121                         $this->getHiddenFields( array( 'limit' ) );
1122         }
1123
1124         /**
1125          * Return true if the named field should be sortable by the UI, false
1126          * otherwise
1127          *
1128          * @param $field String
1129          */
1130         abstract function isFieldSortable( $field );
1131
1132         /**
1133          * Format a table cell. The return value should be HTML, but use an empty
1134          * string not &#160; for empty cells. Do not include the <td> and </td>.
1135          *
1136          * The current result row is available as $this->mCurrentRow, in case you
1137          * need more context.
1138          *
1139          * @param $name String: the database field name
1140          * @param $value String: the value retrieved from the database
1141          */
1142         abstract function formatValue( $name, $value );
1143
1144         /**
1145          * The database field name used as a default sort order
1146          */
1147         abstract function getDefaultSort();
1148
1149         /**
1150          * An array mapping database field names to a textual description of the
1151          * field name, for use in the table header. The description should be plain
1152          * text, it will be HTML-escaped later.
1153          */
1154         abstract function getFieldNames();
1155 }