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 extends ContextSource 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         public $mIsLast;
  99
 100         protected $mLastShown, $mFirstShown, $mPastTheEndIndex, $mDefaultQuery, $mNavigationBar;
 101
 102         /**
 103          * Result object for the query. Warning: seek before use.
 104          *
 105          * @var ResultWrapper
 106          */
 107         public $mResult;
 108
 109         public function __construct( IContextSource $context = null ) {
 110                 if ( $context ) {
 111                         $this->setContext( $context );
 112                 }
 113
 114                 $this->mRequest = $this->getRequest();
 115
 116                 # NB: the offset is quoted, not validated. It is treated as an
 117                 # arbitrary string to support the widest variety of index types. Be
 118                 # careful outputting it into HTML!
 119                 $this->mOffset = $this->mRequest->getText( 'offset' );
 120
 121                 # Use consistent behavior for the limit options
 122                 $this->mDefaultLimit = intval( $this->getUser()->getOption( 'rclimit' ) );
 123                 list( $this->mLimit, /* $offset */ ) = $this->mRequest->getLimitOffset();
 124
 125                 $this->mIsBackwards = ( $this->mRequest->getVal( 'dir' ) == 'prev' );
 126                 $this->mDb = wfGetDB( DB_SLAVE );
 127
 128                 $index = $this->getIndexField(); // column to sort on
 129                 $extraSort = $this->getExtraSortFields(); // extra columns to sort on for query planning
 130                 $order = $this->mRequest->getVal( 'order' );
 131                 if( is_array( $index ) && isset( $index[$order] ) ) {
 132                         $this->mOrderType = $order;
 133                         $this->mIndexField = $index[$order];
 134                         $this->mExtraSortFields = isset( $extraSort[$order] )
 135                                 ? (array)$extraSort[$order]
 136                                 : array();
 137                 } elseif( is_array( $index ) ) {
 138                         # First element is the default
 139                         reset( $index );
 140                         list( $this->mOrderType, $this->mIndexField ) = each( $index );
 141                         $this->mExtraSortFields = isset( $extraSort[$this->mOrderType] )
 142                                 ? (array)$extraSort[$this->mOrderType]
 143                                 : array();
 144                 } else {
 145                         # $index is not an array
 146                         $this->mOrderType = null;
 147                         $this->mIndexField = $index;
 148                         $this->mExtraSortFields = (array)$extraSort;
 149                 }
 150
 151                 if( !isset( $this->mDefaultDirection ) ) {
 152                         $dir = $this->getDefaultDirections();
 153                         $this->mDefaultDirection = is_array( $dir )
 154                                 ? $dir[$this->mOrderType]
 155                                 : $dir;
 156                 }
 157         }
 158
 159         /**
 160          * Do the query, using information from the object context. This function
 161          * has been kept minimal to make it overridable if necessary, to allow for
 162          * result sets formed from multiple DB queries.
 163          */
 164         public function doQuery() {
 165                 # Use the child class name for profiling
 166                 $fname = __METHOD__ . ' (' . get_class( $this ) . ')';
 167                 wfProfileIn( $fname );
 168
 169                 $descending = ( $this->mIsBackwards == $this->mDefaultDirection );
 170                 # Plus an extra row so that we can tell the "next" link should be shown
 171                 $queryLimit = $this->mLimit + 1;
 172
 173                 $this->mResult = $this->reallyDoQuery(
 174                         $this->mOffset,
 175                         $queryLimit,
 176                         $descending
 177                 );
 178                 $this->extractResultInfo( $this->mOffset, $queryLimit, $this->mResult );
 179                 $this->mQueryDone = true;
 180
 181                 $this->preprocessResults( $this->mResult );
 182                 $this->mResult->rewind(); // Paranoia
 183
 184                 wfProfileOut( $fname );
 185         }
 186
 187         /**
 188          * @return ResultWrapper The result wrapper.
 189          */
 190         function getResult() {
 191                 return $this->mResult;
 192         }
 193
 194         /**
 195          * Set the offset from an other source than the request
 196          *
 197          * @param $offset Int|String
 198          */
 199         function setOffset( $offset ) {
 200                 $this->mOffset = $offset;
 201         }
 202         /**
 203          * Set the limit from an other source than the request
 204          *
 205          * @param $limit Int|String
 206          */
 207         function setLimit( $limit ) {
 208                 $this->mLimit = $limit;
 209         }
 210
 211         /**
 212          * Extract some useful data from the result object for use by
 213          * the navigation bar, put it into $this
 214          *
 215          * @param $offset String: index offset, inclusive
 216          * @param $limit Integer: exact query limit
 217          * @param $res ResultWrapper
 218          */
 219         function extractResultInfo( $offset, $limit, ResultWrapper $res ) {
 220                 $numRows = $res->numRows();
 221                 if ( $numRows ) {
 222                         # Remove any table prefix from index field
 223                         $parts = explode( '.', $this->mIndexField );
 224                         $indexColumn = end( $parts );
 225
 226                         $row = $res->fetchRow();
 227                         $firstIndex = $row[$indexColumn];
 228
 229                         # Discard the extra result row if there is one
 230                         if ( $numRows > $this->mLimit && $numRows > 1 ) {
 231                                 $res->seek( $numRows - 1 );
 232                                 $this->mPastTheEndRow = $res->fetchObject();
 233                                 $indexField = $this->mIndexField;
 234                                 $this->mPastTheEndIndex = $this->mPastTheEndRow->$indexField;
 235                                 $res->seek( $numRows - 2 );
 236                                 $row = $res->fetchRow();
 237                                 $lastIndex = $row[$indexColumn];
 238                         } else {
 239                                 $this->mPastTheEndRow = null;
 240                                 # Setting indexes to an empty string means that they will be
 241                                 # omitted if they would otherwise appear in URLs. It just so
 242                                 # happens that this  is the right thing to do in the standard
 243                                 # UI, in all the relevant cases.
 244                                 $this->mPastTheEndIndex = '';
 245                                 $res->seek( $numRows - 1 );
 246                                 $row = $res->fetchRow();
 247                                 $lastIndex = $row[$indexColumn];
 248                         }
 249                 } else {
 250                         $firstIndex = '';
 251                         $lastIndex = '';
 252                         $this->mPastTheEndRow = null;
 253                         $this->mPastTheEndIndex = '';
 254                 }
 255
 256                 if ( $this->mIsBackwards ) {
 257                         $this->mIsFirst = ( $numRows < $limit );
 258                         $this->mIsLast = ( $offset == '' );
 259                         $this->mLastShown = $firstIndex;
 260                         $this->mFirstShown = $lastIndex;
 261                 } else {
 262                         $this->mIsFirst = ( $offset == '' );
 263                         $this->mIsLast = ( $numRows < $limit );
 264                         $this->mLastShown = $lastIndex;
 265                         $this->mFirstShown = $firstIndex;
 266                 }
 267         }
 268
 269         /**
 270          * Get some text to go in brackets in the "function name" part of the SQL comment
 271          *
 272          * @return String
 273          */
 274         function getSqlComment() {
 275                 return get_class( $this );
 276         }
 277
 278         /**
 279          * Do a query with specified parameters, rather than using the object
 280          * context
 281          *
 282          * @param $offset String: index offset, inclusive
 283          * @param $limit Integer: exact query limit
 284          * @param $descending Boolean: query direction, false for ascending, true for descending
 285          * @return ResultWrapper
 286          */
 287         function reallyDoQuery( $offset, $limit, $descending ) {
 288                 $fname = __METHOD__ . ' (' . $this->getSqlComment() . ')';
 289                 $info = $this->getQueryInfo();
 290                 $tables = $info['tables'];
 291                 $fields = $info['fields'];
 292                 $conds = isset( $info['conds'] ) ? $info['conds'] : array();
 293                 $options = isset( $info['options'] ) ? $info['options'] : array();
 294                 $join_conds = isset( $info['join_conds'] ) ? $info['join_conds'] : array();
 295                 $sortColumns = array_merge( array( $this->mIndexField ), $this->mExtraSortFields );
 296                 if ( $descending ) {
 297                         $options['ORDER BY'] = implode( ',', $sortColumns );
 298                         $operator = '>';
 299                 } else {
 300                         $orderBy = array();
 301                         foreach ( $sortColumns as $col ) {
 302                                 $orderBy[] = $col . ' DESC';
 303                         }
 304                         $options['ORDER BY'] = implode( ',', $orderBy );
 305                         $operator = '<';
 306                 }
 307                 if ( $offset != '' ) {
 308                         $conds[] = $this->mIndexField . $operator . $this->mDb->addQuotes( $offset );
 309                 }
 310                 $options['LIMIT'] = intval( $limit );
 311                 $res = $this->mDb->select( $tables, $fields, $conds, $fname, $options, $join_conds );
 312                 return new ResultWrapper( $this->mDb, $res );
 313         }
 314
 315         /**
 316          * Pre-process results; useful for performing batch existence checks, etc.
 317          *
 318          * @param $result ResultWrapper
 319          */
 320         protected function preprocessResults( $result ) {}
 321
 322         /**
 323          * Get the formatted result list. Calls getStartBody(), formatRow() and
 324          * getEndBody(), concatenates the results and returns them.
 325          *
 326          * @return String
 327          */
 328         public function getBody() {
 329                 if ( !$this->mQueryDone ) {
 330                         $this->doQuery();
 331                 }
 332
 333                 if ( $this->mResult->numRows() ) {
 334                         # Do any special query batches before display
 335                         $this->doBatchLookups();
 336                 }
 337
 338                 # Don't use any extra rows returned by the query
 339                 $numRows = min( $this->mResult->numRows(), $this->mLimit );
 340
 341                 $s = $this->getStartBody();
 342                 if ( $numRows ) {
 343                         if ( $this->mIsBackwards ) {
 344                                 for ( $i = $numRows - 1; $i >= 0; $i-- ) {
 345                                         $this->mResult->seek( $i );
 346                                         $row = $this->mResult->fetchObject();
 347                                         $s .= $this->formatRow( $row );
 348                                 }
 349                         } else {
 350                                 $this->mResult->seek( 0 );
 351                                 for ( $i = 0; $i < $numRows; $i++ ) {
 352                                         $row = $this->mResult->fetchObject();
 353                                         $s .= $this->formatRow( $row );
 354                                 }
 355                         }
 356                 } else {
 357                         $s .= $this->getEmptyBody();
 358                 }
 359                 $s .= $this->getEndBody();
 360                 return $s;
 361         }
 362
 363         /**
 364          * Make a self-link
 365          *
 366          * @param $text String: text displayed on the link
 367          * @param $query Array: associative array of paramter to be in the query string
 368          * @param $type String: value of the "rel" attribute
 369          * @return String: HTML fragment
 370          */
 371         function makeLink($text, $query = null, $type=null) {
 372                 if ( $query === null ) {
 373                         return $text;
 374                 }
 375
 376                 $attrs = array();
 377                 if( in_array( $type, array( 'first', 'prev', 'next', 'last' ) ) ) {
 378                         # HTML5 rel attributes
 379                         $attrs['rel'] = $type;
 380                 }
 381
 382                 if( $type ) {
 383                         $attrs['class'] = "mw-{$type}link";
 384                 }
 385                 return Linker::linkKnown(
 386                         $this->getTitle(),
 387                         $text,
 388                         $attrs,
 389                         $query + $this->getDefaultQuery()
 390                 );
 391         }
 392
 393         /**
 394          * Called from getBody(), before getStartBody() is called and
 395          * after doQuery() was called. This will be called only if there
 396          * are rows in the result set.
 397          *
 398          * @return void
 399          */
 400         protected function doBatchLookups() {}
 401
 402         /**
 403          * Hook into getBody(), allows text to be inserted at the start. This
 404          * will be called even if there are no rows in the result set.
 405          *
 406          * @return String
 407          */
 408         protected function getStartBody() {
 409                 return '';
 410         }
 411
 412         /**
 413          * Hook into getBody() for the end of the list
 414          *
 415          * @return String
 416          */
 417         protected function getEndBody() {
 418                 return '';
 419         }
 420
 421         /**
 422          * Hook into getBody(), for the bit between the start and the
 423          * end when there are no rows
 424          *
 425          * @return String
 426          */
 427         protected function getEmptyBody() {
 428                 return '';
 429         }
 430
 431         /**
 432          * Get an array of query parameters that should be put into self-links.
 433          * By default, all parameters passed in the URL are used, except for a
 434          * short blacklist.
 435          *
 436          * @return array Associative array
 437          */
 438         function getDefaultQuery() {
 439                 if ( !isset( $this->mDefaultQuery ) ) {
 440                         $this->mDefaultQuery = $this->getRequest()->getQueryValues();
 441                         unset( $this->mDefaultQuery['title'] );
 442                         unset( $this->mDefaultQuery['dir'] );
 443                         unset( $this->mDefaultQuery['offset'] );
 444                         unset( $this->mDefaultQuery['limit'] );
 445                         unset( $this->mDefaultQuery['order'] );
 446                         unset( $this->mDefaultQuery['month'] );
 447                         unset( $this->mDefaultQuery['year'] );
 448                 }
 449                 return $this->mDefaultQuery;
 450         }
 451
 452         /**
 453          * Get the number of rows in the result set
 454          *
 455          * @return Integer
 456          */
 457         function getNumRows() {
 458                 if ( !$this->mQueryDone ) {
 459                         $this->doQuery();
 460                 }
 461                 return $this->mResult->numRows();
 462         }
 463
 464         /**
 465          * Get a URL query array for the prev, next, first and last links.
 466          *
 467          * @return Array
 468          */
 469         function getPagingQueries() {
 470                 if ( !$this->mQueryDone ) {
 471                         $this->doQuery();
 472                 }
 473
 474                 # Don't announce the limit everywhere if it's the default
 475                 $urlLimit = $this->mLimit == $this->mDefaultLimit ? null : $this->mLimit;
 476
 477                 if ( $this->mIsFirst ) {
 478                         $prev = false;
 479                         $first = false;
 480                 } else {
 481                         $prev = array(
 482                                 'dir' => 'prev',
 483                                 'offset' => $this->mFirstShown,
 484                                 'limit' => $urlLimit
 485                         );
 486                         $first = array( 'limit' => $urlLimit );
 487                 }
 488                 if ( $this->mIsLast ) {
 489                         $next = false;
 490                         $last = false;
 491                 } else {
 492                         $next = array( 'offset' => $this->mLastShown, 'limit' => $urlLimit );
 493                         $last = array( 'dir' => 'prev', 'limit' => $urlLimit );
 494                 }
 495                 return array(
 496                         'prev' => $prev,
 497                         'next' => $next,
 498                         'first' => $first,
 499                         'last' => $last
 500                 );
 501         }
 502
 503         /**
 504          * Returns whether to show the "navigation bar"
 505          *
 506          * @return Boolean
 507          */
 508         function isNavigationBarShown() {
 509                 if ( !$this->mQueryDone ) {
 510                         $this->doQuery();
 511                 }
 512                 // Hide navigation by default if there is nothing to page
 513                 return !($this->mIsFirst && $this->mIsLast);
 514         }
 515
 516         /**
 517          * Get paging links. If a link is disabled, the item from $disabledTexts
 518          * will be used. If there is no such item, the unlinked text from
 519          * $linkTexts will be used. Both $linkTexts and $disabledTexts are arrays
 520          * of HTML.
 521          *
 522          * @param $linkTexts Array
 523          * @param $disabledTexts Array
 524          * @return Array
 525          */
 526         function getPagingLinks( $linkTexts, $disabledTexts = array() ) {
 527                 $queries = $this->getPagingQueries();
 528                 $links = array();
 529                 foreach ( $queries as $type => $query ) {
 530                         if ( $query !== false ) {
 531                                 $links[$type] = $this->makeLink(
 532                                         $linkTexts[$type],
 533                                         $queries[$type],
 534                                         $type
 535                                 );
 536                         } elseif ( isset( $disabledTexts[$type] ) ) {
 537                                 $links[$type] = $disabledTexts[$type];
 538                         } else {
 539                                 $links[$type] = $linkTexts[$type];
 540                         }
 541                 }
 542                 return $links;
 543         }
 544
 545         function getLimitLinks() {
 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                                 $this->getLanguage()->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          * $this->mDefaultDirection member variable.  That's the default for this
 632          * particular instantiation, which is a single value.  This is the set of
 633          * all defaults for the class.
 634          *
 635          * @return Boolean
 636          */
 637         protected function getDefaultDirections() { return false; }
 638 }
 639
 640
 641 /**
 642  * IndexPager with an alphabetic list and a formatted navigation bar
 643  * @ingroup Pager
 644  */
 645 abstract class AlphabeticPager extends IndexPager {
 646
 647         /**
 648          * Shamelessly stolen bits from ReverseChronologicalPager,
 649          * didn't want to do class magic as may be still revamped
 650          *
 651          * @return String HTML
 652          */
 653         function getNavigationBar() {
 654                 if ( !$this->isNavigationBarShown() ) return '';
 655
 656                 if( isset( $this->mNavigationBar ) ) {
 657                         return $this->mNavigationBar;
 658                 }
 659
 660                 $lang = $this->getLanguage();
 661
 662                 $opts = array( 'parsemag', 'escapenoentities' );
 663                 $linkTexts = array(
 664                         'prev' => wfMsgExt(
 665                                 'prevn',
 666                                 $opts,
 667                                 $lang->formatNum( $this->mLimit )
 668                         ),
 669                         'next' => wfMsgExt(
 670                                 'nextn',
 671                                 $opts,
 672                                 $lang->formatNum($this->mLimit )
 673                         ),
 674                         'first' => wfMsgExt( 'page_first', $opts ),
 675                         'last' => wfMsgExt( 'page_last', $opts )
 676                 );
 677
 678                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 679                 $limitLinks = $this->getLimitLinks();
 680                 $limits = $lang->pipeList( $limitLinks );
 681
 682                 $this->mNavigationBar = wfMessage( 'parentheses' )->rawParams(
 683                         $lang->pipeList(
 684                                 array( $pagingLinks['first'],
 685                                 $pagingLinks['last'] )
 686                         ) )->escaped() . " " .
 687                         wfMsgHtml( 'viewprevnext', $pagingLinks['prev'],
 688                         $pagingLinks['next'], $limits );
 689
 690                 if( !is_array( $this->getIndexField() ) ) {
 691                         # Early return to avoid undue nesting
 692                         return $this->mNavigationBar;
 693                 }
 694
 695                 $extra = '';
 696                 $first = true;
 697                 $msgs = $this->getOrderTypeMessages();
 698                 foreach( array_keys( $msgs ) as $order ) {
 699                         if( $first ) {
 700                                 $first = false;
 701                         } else {
 702                                 $extra .= wfMsgExt( 'pipe-separator' , 'escapenoentities' );
 703                         }
 704
 705                         if( $order == $this->mOrderType ) {
 706                                 $extra .= wfMsgHTML( $msgs[$order] );
 707                         } else {
 708                                 $extra .= $this->makeLink(
 709                                         wfMsgHTML( $msgs[$order] ),
 710                                         array( 'order' => $order )
 711                                 );
 712                         }
 713                 }
 714
 715                 if( $extra !== '' ) {
 716                         $extra = ' ' . wfMessage( 'parentheses' )->rawParams( $extra )->escaped();
 717                         $this->mNavigationBar .= $extra;
 718                 }
 719
 720                 return $this->mNavigationBar;
 721         }
 722
 723         /**
 724          * If this supports multiple order type messages, give the message key for
 725          * enabling each one in getNavigationBar.  The return type is an associa-
 726          * tive array whose keys must exactly match the keys of the array returned
 727          * by getIndexField(), and whose values are message keys.
 728          *
 729          * @return Array
 730          */
 731         protected function getOrderTypeMessages() {
 732                 return null;
 733         }
 734 }
 735
 736 /**
 737  * IndexPager with a formatted navigation bar
 738  * @ingroup Pager
 739  */
 740 abstract class ReverseChronologicalPager extends IndexPager {
 741         public $mDefaultDirection = true;
 742         public $mYear;
 743         public $mMonth;
 744
 745         function getNavigationBar() {
 746                 if ( !$this->isNavigationBarShown() ) {
 747                         return '';
 748                 }
 749
 750                 if ( isset( $this->mNavigationBar ) ) {
 751                         return $this->mNavigationBar;
 752                 }
 753
 754                 $nicenumber = $this->getLanguage()->formatNum( $this->mLimit );
 755                 $linkTexts = array(
 756                         'prev' => wfMsgExt(
 757                                 'pager-newer-n',
 758                                 array( 'parsemag', 'escape' ),
 759                                 $nicenumber
 760                         ),
 761                         'next' => wfMsgExt(
 762                                 'pager-older-n',
 763                                 array( 'parsemag', 'escape' ),
 764                                 $nicenumber
 765                         ),
 766                         'first' => wfMsgHtml( 'histlast' ),
 767                         'last' => wfMsgHtml( 'histfirst' )
 768                 );
 769
 770                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 771                 $limitLinks = $this->getLimitLinks();
 772                 $limits = $this->getLanguage()->pipeList( $limitLinks );
 773                 $firstLastLinks = wfMessage( 'parentheses' )->rawParams( "{$pagingLinks['first']}" .
 774                         wfMsgExt( 'pipe-separator' , 'escapenoentities' ) .
 775                         "{$pagingLinks['last']}" )->escaped();
 776
 777                 $this->mNavigationBar = $firstLastLinks . ' ' .
 778                         wfMsgHTML(
 779                                 'viewprevnext',
 780                                 $pagingLinks['prev'], $pagingLinks['next'],
 781                                 $limits
 782                         );
 783
 784                 return $this->mNavigationBar;
 785         }
 786
 787         function getDateCond( $year, $month ) {
 788                 $year = intval( $year );
 789                 $month = intval( $month );
 790                 // Basic validity checks
 791                 $this->mYear = $year > 0 ? $year : false;
 792                 $this->mMonth = ( $month > 0 && $month < 13 ) ? $month : false;
 793                 // Given an optional year and month, we need to generate a timestamp
 794                 // to use as "WHERE rev_timestamp <= result"
 795                 // Examples: year = 2006 equals < 20070101 (+000000)
 796                 // year=2005, month=1    equals < 20050201
 797                 // year=2005, month=12   equals < 20060101
 798                 if ( !$this->mYear && !$this->mMonth ) {
 799                         return;
 800                 }
 801                 if ( $this->mYear ) {
 802                         $year = $this->mYear;
 803                 } else {
 804                         // If no year given, assume the current one
 805                         $year = gmdate( 'Y' );
 806                         // If this month hasn't happened yet this year, go back to last year's month
 807                         if( $this->mMonth > gmdate( 'n' ) ) {
 808                                 $year--;
 809                         }
 810                 }
 811                 if ( $this->mMonth ) {
 812                         $month = $this->mMonth + 1;
 813                         // For December, we want January 1 of the next year
 814                         if ($month > 12) {
 815                                 $month = 1;
 816                                 $year++;
 817                         }
 818                 } else {
 819                         // No month implies we want up to the end of the year in question
 820                         $month = 1;
 821                         $year++;
 822                 }
 823                 // Y2K38 bug
 824                 if ( $year > 2032 ) {
 825                         $year = 2032;
 826                 }
 827                 $ymd = (int)sprintf( "%04d%02d01", $year, $month );
 828                 if ( $ymd > 20320101 ) {
 829                         $ymd = 20320101;
 830                 }
 831                 $this->mOffset = $this->mDb->timestamp( "${ymd}000000" );
 832         }
 833 }
 834
 835 /**
 836  * Table-based display with a user-selectable sort order
 837  * @ingroup Pager
 838  */
 839 abstract class TablePager extends IndexPager {
 840         var $mSort;
 841         var $mCurrentRow;
 842
 843         public function __construct( IContextSource $context = null ) {
 844                 if ( $context ) {
 845                         $this->setContext( $context );
 846                 }
 847
 848                 $this->mSort = $this->getRequest()->getText( 'sort' );
 849                 if ( !array_key_exists( $this->mSort, $this->getFieldNames() ) ) {
 850                         $this->mSort = $this->getDefaultSort();
 851                 }
 852                 if ( $this->getRequest()->getBool( 'asc' ) ) {
 853                         $this->mDefaultDirection = false;
 854                 } elseif ( $this->getRequest()->getBool( 'desc' ) ) {
 855                         $this->mDefaultDirection = true;
 856                 } /* Else leave it at whatever the class default is */
 857
 858                 parent::__construct();
 859         }
 860
 861         /**
 862          * @protected
 863          * @return string
 864          */
 865         function getStartBody() {
 866                 global $wgStylePath;
 867                 $tableClass = htmlspecialchars( $this->getTableClass() );
 868                 $sortClass = htmlspecialchars( $this->getSortHeaderClass() );
 869
 870                 $s = "<table style='border:1;' class=\"mw-datatable $tableClass\"><thead><tr>\n";
 871                 $fields = $this->getFieldNames();
 872
 873                 # Make table header
 874                 foreach ( $fields as $field => $name ) {
 875                         if ( strval( $name ) == '' ) {
 876                                 $s .= "<th>&#160;</th>\n";
 877                         } elseif ( $this->isFieldSortable( $field ) ) {
 878                                 $query = array( 'sort' => $field, 'limit' => $this->mLimit );
 879                                 if ( $field == $this->mSort ) {
 880                                         # This is the sorted column
 881                                         # Prepare a link that goes in the other sort order
 882                                         if ( $this->mDefaultDirection ) {
 883                                                 # Descending
 884                                                 $image = 'Arr_d.png';
 885                                                 $query['asc'] = '1';
 886                                                 $query['desc'] = '';
 887                                                 $alt = htmlspecialchars( wfMsg( 'descending_abbrev' ) );
 888                                         } else {
 889                                                 # Ascending
 890                                                 $image = 'Arr_u.png';
 891                                                 $query['asc'] = '';
 892                                                 $query['desc'] = '1';
 893                                                 $alt = htmlspecialchars( wfMsg( 'ascending_abbrev' ) );
 894                                         }
 895                                         $image = htmlspecialchars( "$wgStylePath/common/images/$image" );
 896                                         $link = $this->makeLink(
 897                                                 "<img width=\"12\" height=\"12\" alt=\"$alt\" src=\"$image\" />" .
 898                                                 htmlspecialchars( $name ), $query );
 899                                         $s .= "<th class=\"$sortClass\">$link</th>\n";
 900                                 } else {
 901                                         $s .= '<th>' . $this->makeLink( htmlspecialchars( $name ), $query ) . "</th>\n";
 902                                 }
 903                         } else {
 904                                 $s .= '<th>' . htmlspecialchars( $name ) . "</th>\n";
 905                         }
 906                 }
 907                 $s .= "</tr></thead><tbody>\n";
 908                 return $s;
 909         }
 910
 911         /**
 912          * @protected
 913          * @return string
 914          */
 915         function getEndBody() {
 916                 return "</tbody></table>\n";
 917         }
 918
 919         /**
 920          * @protected
 921          * @return string
 922          */
 923         function getEmptyBody() {
 924                 $colspan = count( $this->getFieldNames() );
 925                 $msgEmpty = wfMsgHtml( 'table_pager_empty' );
 926                 return "<tr><td colspan=\"$colspan\">$msgEmpty</td></tr>\n";
 927         }
 928
 929         /**
 930          * @protected
 931          * @param stdClass $row
 932          * @return String HTML
 933          */
 934         function formatRow( $row ) {
 935                 $this->mCurrentRow = $row; // In case formatValue etc need to know
 936                 $s = Xml::openElement( 'tr', $this->getRowAttrs( $row ) );
 937                 $fieldNames = $this->getFieldNames();
 938
 939                 foreach ( $fieldNames as $field => $name ) {
 940                         $value = isset( $row->$field ) ? $row->$field : null;
 941                         $formatted = strval( $this->formatValue( $field, $value ) );
 942
 943                         if ( $formatted == '' ) {
 944                                 $formatted = '&#160;';
 945                         }
 946
 947                         $s .= Xml::tags( 'td', $this->getCellAttrs( $field, $value ), $formatted );
 948                 }
 949
 950                 $s .= "</tr>\n";
 951
 952                 return $s;
 953         }
 954
 955         /**
 956          * Get a class name to be applied to the given row.
 957          *
 958          * @protected
 959          *
 960          * @param $row Object: the database result row
 961          * @return String
 962          */
 963         function getRowClass( $row ) {
 964                 return '';
 965         }
 966
 967         /**
 968          * Get attributes to be applied to the given row.
 969          *
 970          * @protected
 971          *
 972          * @param $row Object: the database result row
 973          * @return Array of <attr> => <value>
 974          */
 975         function getRowAttrs( $row ) {
 976                 $class = $this->getRowClass( $row );
 977                 if ( $class === '' ) {
 978                         // Return an empty array to avoid clutter in HTML like class=""
 979                         return array();
 980                 } else {
 981                         return array( 'class' => $this->getRowClass( $row ) );
 982                 }
 983         }
 984
 985         /**
 986          * Get any extra attributes to be applied to the given cell. Don't
 987          * take this as an excuse to hardcode styles; use classes and
 988          * CSS instead.  Row context is available in $this->mCurrentRow
 989          *
 990          * @protected
 991          *
 992          * @param $field String The column
 993          * @param $value String The cell contents
 994          * @return Array of attr => value
 995          */
 996         function getCellAttrs( $field, $value ) {
 997                 return array( 'class' => 'TablePager_col_' . $field );
 998         }
 999
1000         /**
1001          * @protected
1002          * @return string
1003          */
1004         function getIndexField() {
1005                 return $this->mSort;
1006         }
1007
1008         /**
1009          * @protected
1010          * @return string
1011          */
1012         function getTableClass() {
1013                 return 'TablePager';
1014         }
1015
1016         /**
1017          * @protected
1018          * @return string
1019          */
1020         function getNavClass() {
1021                 return 'TablePager_nav';
1022         }
1023
1024         /**
1025          * @protected
1026          * @return string
1027          */
1028         function getSortHeaderClass() {
1029                 return 'TablePager_sort';
1030         }
1031
1032         /**
1033          * A navigation bar with images
1034          * @return String HTML
1035          */
1036         public function getNavigationBar() {
1037                 global $wgStylePath;
1038
1039                 if ( !$this->isNavigationBarShown() ) {
1040                         return '';
1041                 }
1042
1043                 $path = "$wgStylePath/common/images";
1044                 $labels = array(
1045                         'first' => 'table_pager_first',
1046                         'prev' => 'table_pager_prev',
1047                         'next' => 'table_pager_next',
1048                         'last' => 'table_pager_last',
1049                 );
1050                 $images = array(
1051                         'first' => 'arrow_first_25.png',
1052                         'prev' => 'arrow_left_25.png',
1053                         'next' => 'arrow_right_25.png',
1054                         'last' => 'arrow_last_25.png',
1055                 );
1056                 $disabledImages = array(
1057                         'first' => 'arrow_disabled_first_25.png',
1058                         'prev' => 'arrow_disabled_left_25.png',
1059                         'next' => 'arrow_disabled_right_25.png',
1060                         'last' => 'arrow_disabled_last_25.png',
1061                 );
1062                 if( $this->getLanguage()->isRTL() ) {
1063                         $keys = array_keys( $labels );
1064                         $images = array_combine( $keys, array_reverse( $images ) );
1065                         $disabledImages = array_combine( $keys, array_reverse( $disabledImages ) );
1066                 }
1067
1068                 $linkTexts = array();
1069                 $disabledTexts = array();
1070                 foreach ( $labels as $type => $label ) {
1071                         $msgLabel = wfMsgHtml( $label );
1072                         $linkTexts[$type] = "<img src=\"$path/{$images[$type]}\" alt=\"$msgLabel\"/><br />$msgLabel";
1073                         $disabledTexts[$type] = "<img src=\"$path/{$disabledImages[$type]}\" alt=\"$msgLabel\"/><br />$msgLabel";
1074                 }
1075                 $links = $this->getPagingLinks( $linkTexts, $disabledTexts );
1076
1077                 $navClass = htmlspecialchars( $this->getNavClass() );
1078                 $s = "<table class=\"$navClass\"><tr>\n";
1079                 $width = 100 / count( $links ) . '%';
1080                 foreach ( $labels as $type => $label ) {
1081                         $s .= "<td style='width:$width;'>{$links[$type]}</td>\n";
1082                 }
1083                 $s .= "</tr></table>\n";
1084                 return $s;
1085         }
1086
1087         /**
1088          * Get a <select> element which has options for each of the allowed limits
1089          *
1090          * @return String: HTML fragment
1091          */
1092         public function getLimitSelect() {
1093                 # Add the current limit from the query string
1094                 # to avoid that the limit is lost after clicking Go next time
1095                 if ( !in_array( $this->mLimit, $this->mLimitsShown ) ) {
1096                         $this->mLimitsShown[] = $this->mLimit;
1097                         sort( $this->mLimitsShown );
1098                 }
1099                 $s = Html::openElement( 'select', array( 'name' => 'limit' ) ) . "\n";
1100                 foreach ( $this->mLimitsShown as $key => $value ) {
1101                         # The pair is either $index => $limit, in which case the $value
1102                         # will be numeric, or $limit => $text, in which case the $value
1103                         # will be a string.
1104                         if( is_int( $value ) ){
1105                                 $limit = $value;
1106                                 $text = $this->getLanguage()->formatNum( $limit );
1107                         } else {
1108                                 $limit = $key;
1109                                 $text = $value;
1110                         }
1111                         $s .= Xml::option( $text, $limit, $limit == $this->mLimit ) . "\n";
1112                 }
1113                 $s .= Html::closeElement( 'select' );
1114                 return $s;
1115         }
1116
1117         /**
1118          * Get <input type="hidden"> elements for use in a method="get" form.
1119          * Resubmits all defined elements of the query string, except for a
1120          * blacklist, passed in the $blacklist parameter.
1121          *
1122          * @param $blacklist Array parameters from the request query which should not be resubmitted
1123          * @return String: HTML fragment
1124          */
1125         function getHiddenFields( $blacklist = array() ) {
1126                 $blacklist = (array)$blacklist;
1127                 $query = $this->getRequest()->getQueryValues();
1128                 foreach ( $blacklist as $name ) {
1129                         unset( $query[$name] );
1130                 }
1131                 $s = '';
1132                 foreach ( $query as $name => $value ) {
1133                         $encName = htmlspecialchars( $name );
1134                         $encValue = htmlspecialchars( $value );
1135                         $s .= "<input type=\"hidden\" name=\"$encName\" value=\"$encValue\"/>\n";
1136                 }
1137                 return $s;
1138         }
1139
1140         /**
1141          * Get a form containing a limit selection dropdown
1142          *
1143          * @return String: HTML fragment
1144          */
1145         function getLimitForm() {
1146                 global $wgScript;
1147
1148                 return Xml::openElement(
1149                         'form',
1150                         array(
1151                                 'method' => 'get',
1152                                 'action' => $wgScript
1153                         ) ) . "\n" . $this->getLimitDropdown() . "</form>\n";
1154         }
1155
1156         /**
1157          * Gets a limit selection dropdown
1158          *
1159          * @return string
1160          */
1161         function getLimitDropdown() {
1162                 # Make the select with some explanatory text
1163                 $msgSubmit = wfMsgHtml( 'table_pager_limit_submit' );
1164
1165                 return wfMsgHtml( 'table_pager_limit', $this->getLimitSelect() ) .
1166                         "\n<input type=\"submit\" value=\"$msgSubmit\"/>\n" .
1167                         $this->getHiddenFields( array( 'limit' ) );
1168         }
1169
1170         /**
1171          * Return true if the named field should be sortable by the UI, false
1172          * otherwise
1173          *
1174          * @param $field String
1175          */
1176         abstract function isFieldSortable( $field );
1177
1178         /**
1179          * Format a table cell. The return value should be HTML, but use an empty
1180          * string not &#160; for empty cells. Do not include the <td> and </td>.
1181          *
1182          * The current result row is available as $this->mCurrentRow, in case you
1183          * need more context.
1184          *
1185          * @protected
1186          *
1187          * @param $name String: the database field name
1188          * @param $value String: the value retrieved from the database
1189          */
1190         abstract function formatValue( $name, $value );
1191
1192         /**
1193          * The database field name used as a default sort order.
1194          *
1195          * @protected
1196          *
1197          * @return string
1198          */
1199         abstract function getDefaultSort();
1200
1201         /**
1202          * An array mapping database field names to a textual description of the
1203          * field name, for use in the table header. The description should be plain
1204          * text, it will be HTML-escaped later.
1205          *
1206          * @return Array
1207          */
1208         abstract function getFieldNames();
1209 }