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          *
 370          * @return String: HTML fragment
 371          */
 372         function makeLink( $text, array $query = null, $type = null ) {
 373                 if ( $query === null ) {
 374                         return $text;
 375                 }
 376
 377                 $attrs = array();
 378                 if( in_array( $type, array( 'first', 'prev', 'next', 'last' ) ) ) {
 379                         # HTML5 rel attributes
 380                         $attrs['rel'] = $type;
 381                 }
 382
 383                 if( $type ) {
 384                         $attrs['class'] = "mw-{$type}link";
 385                 }
 386
 387                 return Linker::linkKnown(
 388                         $this->getTitle(),
 389                         $text,
 390                         $attrs,
 391                         $query + $this->getDefaultQuery()
 392                 );
 393         }
 394
 395         /**
 396          * Called from getBody(), before getStartBody() is called and
 397          * after doQuery() was called. This will be called only if there
 398          * are rows in the result set.
 399          *
 400          * @return void
 401          */
 402         protected function doBatchLookups() {}
 403
 404         /**
 405          * Hook into getBody(), allows text to be inserted at the start. This
 406          * will be called even if there are no rows in the result set.
 407          *
 408          * @return String
 409          */
 410         protected function getStartBody() {
 411                 return '';
 412         }
 413
 414         /**
 415          * Hook into getBody() for the end of the list
 416          *
 417          * @return String
 418          */
 419         protected function getEndBody() {
 420                 return '';
 421         }
 422
 423         /**
 424          * Hook into getBody(), for the bit between the start and the
 425          * end when there are no rows
 426          *
 427          * @return String
 428          */
 429         protected function getEmptyBody() {
 430                 return '';
 431         }
 432
 433         /**
 434          * Get an array of query parameters that should be put into self-links.
 435          * By default, all parameters passed in the URL are used, except for a
 436          * short blacklist.
 437          *
 438          * @return array Associative array
 439          */
 440         function getDefaultQuery() {
 441                 if ( !isset( $this->mDefaultQuery ) ) {
 442                         $this->mDefaultQuery = $this->getRequest()->getQueryValues();
 443                         unset( $this->mDefaultQuery['title'] );
 444                         unset( $this->mDefaultQuery['dir'] );
 445                         unset( $this->mDefaultQuery['offset'] );
 446                         unset( $this->mDefaultQuery['limit'] );
 447                         unset( $this->mDefaultQuery['order'] );
 448                         unset( $this->mDefaultQuery['month'] );
 449                         unset( $this->mDefaultQuery['year'] );
 450                 }
 451                 return $this->mDefaultQuery;
 452         }
 453
 454         /**
 455          * Get the number of rows in the result set
 456          *
 457          * @return Integer
 458          */
 459         function getNumRows() {
 460                 if ( !$this->mQueryDone ) {
 461                         $this->doQuery();
 462                 }
 463                 return $this->mResult->numRows();
 464         }
 465
 466         /**
 467          * Get a URL query array for the prev, next, first and last links.
 468          *
 469          * @return Array
 470          */
 471         function getPagingQueries() {
 472                 if ( !$this->mQueryDone ) {
 473                         $this->doQuery();
 474                 }
 475
 476                 # Don't announce the limit everywhere if it's the default
 477                 $urlLimit = $this->mLimit == $this->mDefaultLimit ? null : $this->mLimit;
 478
 479                 if ( $this->mIsFirst ) {
 480                         $prev = false;
 481                         $first = false;
 482                 } else {
 483                         $prev = array(
 484                                 'dir' => 'prev',
 485                                 'offset' => $this->mFirstShown,
 486                                 'limit' => $urlLimit
 487                         );
 488                         $first = array( 'limit' => $urlLimit );
 489                 }
 490                 if ( $this->mIsLast ) {
 491                         $next = false;
 492                         $last = false;
 493                 } else {
 494                         $next = array( 'offset' => $this->mLastShown, 'limit' => $urlLimit );
 495                         $last = array( 'dir' => 'prev', 'limit' => $urlLimit );
 496                 }
 497                 return array(
 498                         'prev' => $prev,
 499                         'next' => $next,
 500                         'first' => $first,
 501                         'last' => $last
 502                 );
 503         }
 504
 505         /**
 506          * Returns whether to show the "navigation bar"
 507          *
 508          * @return Boolean
 509          */
 510         function isNavigationBarShown() {
 511                 if ( !$this->mQueryDone ) {
 512                         $this->doQuery();
 513                 }
 514                 // Hide navigation by default if there is nothing to page
 515                 return !($this->mIsFirst && $this->mIsLast);
 516         }
 517
 518         /**
 519          * Get paging links. If a link is disabled, the item from $disabledTexts
 520          * will be used. If there is no such item, the unlinked text from
 521          * $linkTexts will be used. Both $linkTexts and $disabledTexts are arrays
 522          * of HTML.
 523          *
 524          * @param $linkTexts Array
 525          * @param $disabledTexts Array
 526          * @return Array
 527          */
 528         function getPagingLinks( $linkTexts, $disabledTexts = array() ) {
 529                 $queries = $this->getPagingQueries();
 530                 $links = array();
 531
 532                 foreach ( $queries as $type => $query ) {
 533                         if ( $query !== false ) {
 534                                 $links[$type] = $this->makeLink(
 535                                         $linkTexts[$type],
 536                                         $queries[$type],
 537                                         $type
 538                                 );
 539                         } elseif ( isset( $disabledTexts[$type] ) ) {
 540                                 $links[$type] = $disabledTexts[$type];
 541                         } else {
 542                                 $links[$type] = $linkTexts[$type];
 543                         }
 544                 }
 545
 546                 return $links;
 547         }
 548
 549         function getLimitLinks() {
 550                 $links = array();
 551                 if ( $this->mIsBackwards ) {
 552                         $offset = $this->mPastTheEndIndex;
 553                 } else {
 554                         $offset = $this->mOffset;
 555                 }
 556                 foreach ( $this->mLimitsShown as $limit ) {
 557                         $links[] = $this->makeLink(
 558                                 $this->getLanguage()->formatNum( $limit ),
 559                                 array( 'offset' => $offset, 'limit' => $limit ),
 560                                 'num'
 561                         );
 562                 }
 563                 return $links;
 564         }
 565
 566         /**
 567          * Abstract formatting function. This should return an HTML string
 568          * representing the result row $row. Rows will be concatenated and
 569          * returned by getBody()
 570          *
 571          * @param $row Object: database row
 572          * @return String
 573          */
 574         abstract function formatRow( $row );
 575
 576         /**
 577          * This function should be overridden to provide all parameters
 578          * needed for the main paged query. It returns an associative
 579          * array with the following elements:
 580          *    tables => Table(s) for passing to Database::select()
 581          *    fields => Field(s) for passing to Database::select(), may be *
 582          *    conds => WHERE conditions
 583          *    options => option array
 584          *    join_conds => JOIN conditions
 585          *
 586          * @return Array
 587          */
 588         abstract function getQueryInfo();
 589
 590         /**
 591          * This function should be overridden to return the name of the index fi-
 592          * eld.  If the pager supports multiple orders, it may return an array of
 593          * 'querykey' => 'indexfield' pairs, so that a request with &count=querykey
 594          * will use indexfield to sort.  In this case, the first returned key is
 595          * the default.
 596          *
 597          * Needless to say, it's really not a good idea to use a non-unique index
 598          * for this!  That won't page right.
 599          *
 600          * @return string|Array
 601          */
 602         abstract function getIndexField();
 603
 604         /**
 605          * This function should be overridden to return the names of secondary columns
 606          * to order by in addition to the column in getIndexField(). These fields will
 607          * not be used in the pager offset or in any links for users.
 608          *
 609          * If getIndexField() returns an array of 'querykey' => 'indexfield' pairs then
 610          * this must return a corresponding array of 'querykey' => array( fields...) pairs
 611          * in order for a request with &count=querykey to use array( fields...) to sort.
 612          *
 613          * This is useful for pagers that GROUP BY a unique column (say page_id)
 614          * and ORDER BY another (say page_len). Using GROUP BY and ORDER BY both on
 615          * page_len,page_id avoids temp tables (given a page_len index). This would
 616          * also work if page_id was non-unique but we had a page_len,page_id index.
 617          *
 618          * @return Array
 619          */
 620         protected function getExtraSortFields() { return array(); }
 621
 622         /**
 623          * Return the default sorting direction: false for ascending, true for de-
 624          * scending.  You can also have an associative array of ordertype => dir,
 625          * if multiple order types are supported.  In this case getIndexField()
 626          * must return an array, and the keys of that must exactly match the keys
 627          * of this.
 628          *
 629          * For backward compatibility, this method's return value will be ignored
 630          * if $this->mDefaultDirection is already set when the constructor is
 631          * called, for instance if it's statically initialized.  In that case the
 632          * value of that variable (which must be a boolean) will be used.
 633          *
 634          * Note that despite its name, this does not return the value of the
 635          * $this->mDefaultDirection member variable.  That's the default for this
 636          * particular instantiation, which is a single value.  This is the set of
 637          * all defaults for the class.
 638          *
 639          * @return Boolean
 640          */
 641         protected function getDefaultDirections() { return false; }
 642 }
 643
 644
 645 /**
 646  * IndexPager with an alphabetic list and a formatted navigation bar
 647  * @ingroup Pager
 648  */
 649 abstract class AlphabeticPager extends IndexPager {
 650
 651         /**
 652          * Shamelessly stolen bits from ReverseChronologicalPager,
 653          * didn't want to do class magic as may be still revamped
 654          *
 655          * @return String HTML
 656          */
 657         function getNavigationBar() {
 658                 if ( !$this->isNavigationBarShown() ) {
 659                         return '';
 660                 }
 661
 662                 if( isset( $this->mNavigationBar ) ) {
 663                         return $this->mNavigationBar;
 664                 }
 665
 666                 $lang = $this->getLanguage();
 667
 668                 $opts = array( 'parsemag', 'escapenoentities' );
 669                 $linkTexts = array(
 670                         'prev' => wfMsgExt(
 671                                 'prevn',
 672                                 $opts,
 673                                 $lang->formatNum( $this->mLimit )
 674                         ),
 675                         'next' => wfMsgExt(
 676                                 'nextn',
 677                                 $opts,
 678                                 $lang->formatNum($this->mLimit )
 679                         ),
 680                         'first' => wfMsgExt( 'page_first', $opts ),
 681                         'last' => wfMsgExt( 'page_last', $opts )
 682                 );
 683
 684                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 685                 $limitLinks = $this->getLimitLinks();
 686                 $limits = $lang->pipeList( $limitLinks );
 687
 688                 $this->mNavigationBar = wfMessage( 'parentheses' )->rawParams(
 689                         $lang->pipeList(
 690                                 array( $pagingLinks['first'],
 691                                         $pagingLinks['last'] )
 692                         ) )->escaped() . " " .
 693                         wfMsgHtml( 'viewprevnext', $pagingLinks['prev'],
 694                                 $pagingLinks['next'], $limits );
 695
 696                 if( !is_array( $this->getIndexField() ) ) {
 697                         # Early return to avoid undue nesting
 698                         return $this->mNavigationBar;
 699                 }
 700
 701                 $extra = '';
 702                 $first = true;
 703                 $msgs = $this->getOrderTypeMessages();
 704                 foreach( array_keys( $msgs ) as $order ) {
 705                         if( $first ) {
 706                                 $first = false;
 707                         } else {
 708                                 $extra .= wfMsgExt( 'pipe-separator' , 'escapenoentities' );
 709                         }
 710
 711                         if( $order == $this->mOrderType ) {
 712                                 $extra .= wfMsgHTML( $msgs[$order] );
 713                         } else {
 714                                 $extra .= $this->makeLink(
 715                                         wfMsgHTML( $msgs[$order] ),
 716                                         array( 'order' => $order )
 717                                 );
 718                         }
 719                 }
 720
 721                 if( $extra !== '' ) {
 722                         $extra = ' ' . wfMessage( 'parentheses' )->rawParams( $extra )->escaped();
 723                         $this->mNavigationBar .= $extra;
 724                 }
 725
 726                 return $this->mNavigationBar;
 727         }
 728
 729         /**
 730          * If this supports multiple order type messages, give the message key for
 731          * enabling each one in getNavigationBar.  The return type is an associa-
 732          * tive array whose keys must exactly match the keys of the array returned
 733          * by getIndexField(), and whose values are message keys.
 734          *
 735          * @return Array
 736          */
 737         protected function getOrderTypeMessages() {
 738                 return null;
 739         }
 740 }
 741
 742 /**
 743  * IndexPager with a formatted navigation bar
 744  * @ingroup Pager
 745  */
 746 abstract class ReverseChronologicalPager extends IndexPager {
 747         public $mDefaultDirection = true;
 748         public $mYear;
 749         public $mMonth;
 750
 751         function getNavigationBar() {
 752                 if ( !$this->isNavigationBarShown() ) {
 753                         return '';
 754                 }
 755
 756                 if ( isset( $this->mNavigationBar ) ) {
 757                         return $this->mNavigationBar;
 758                 }
 759
 760                 $nicenumber = $this->getLanguage()->formatNum( $this->mLimit );
 761                 $linkTexts = array(
 762                         'prev' => wfMsgExt(
 763                                 'pager-newer-n',
 764                                 array( 'parsemag', 'escape' ),
 765                                 $nicenumber
 766                         ),
 767                         'next' => wfMsgExt(
 768                                 'pager-older-n',
 769                                 array( 'parsemag', 'escape' ),
 770                                 $nicenumber
 771                         ),
 772                         'first' => wfMsgHtml( 'histlast' ),
 773                         'last' => wfMsgHtml( 'histfirst' )
 774                 );
 775
 776                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 777                 $limitLinks = $this->getLimitLinks();
 778                 $limits = $this->getLanguage()->pipeList( $limitLinks );
 779                 $firstLastLinks = wfMessage( 'parentheses' )->rawParams( "{$pagingLinks['first']}" .
 780                         wfMsgExt( 'pipe-separator' , 'escapenoentities' ) .
 781                         "{$pagingLinks['last']}" )->escaped();
 782
 783                 $this->mNavigationBar = $firstLastLinks . ' ' .
 784                         wfMsgHTML(
 785                                 'viewprevnext',
 786                                 $pagingLinks['prev'], $pagingLinks['next'],
 787                                 $limits
 788                         );
 789
 790                 return $this->mNavigationBar;
 791         }
 792
 793         function getDateCond( $year, $month ) {
 794                 $year = intval( $year );
 795                 $month = intval( $month );
 796
 797                 // Basic validity checks
 798                 $this->mYear = $year > 0 ? $year : false;
 799                 $this->mMonth = ( $month > 0 && $month < 13 ) ? $month : false;
 800
 801                 // Given an optional year and month, we need to generate a timestamp
 802                 // to use as "WHERE rev_timestamp <= result"
 803                 // Examples: year = 2006 equals < 20070101 (+000000)
 804                 // year=2005, month=1    equals < 20050201
 805                 // year=2005, month=12   equals < 20060101
 806                 if ( !$this->mYear && !$this->mMonth ) {
 807                         return;
 808                 }
 809
 810                 if ( $this->mYear ) {
 811                         $year = $this->mYear;
 812                 } else {
 813                         // If no year given, assume the current one
 814                         $year = gmdate( 'Y' );
 815                         // If this month hasn't happened yet this year, go back to last year's month
 816                         if( $this->mMonth > gmdate( 'n' ) ) {
 817                                 $year--;
 818                         }
 819                 }
 820
 821                 if ( $this->mMonth ) {
 822                         $month = $this->mMonth + 1;
 823                         // For December, we want January 1 of the next year
 824                         if ($month > 12) {
 825                                 $month = 1;
 826                                 $year++;
 827                         }
 828                 } else {
 829                         // No month implies we want up to the end of the year in question
 830                         $month = 1;
 831                         $year++;
 832                 }
 833
 834                 // Y2K38 bug
 835                 if ( $year > 2032 ) {
 836                         $year = 2032;
 837                 }
 838
 839                 $ymd = (int)sprintf( "%04d%02d01", $year, $month );
 840
 841                 if ( $ymd > 20320101 ) {
 842                         $ymd = 20320101;
 843                 }
 844
 845                 $this->mOffset = $this->mDb->timestamp( "${ymd}000000" );
 846         }
 847 }
 848
 849 /**
 850  * Table-based display with a user-selectable sort order
 851  * @ingroup Pager
 852  */
 853 abstract class TablePager extends IndexPager {
 854         var $mSort;
 855         var $mCurrentRow;
 856
 857         public function __construct( IContextSource $context = null ) {
 858                 if ( $context ) {
 859                         $this->setContext( $context );
 860                 }
 861
 862                 $this->mSort = $this->getRequest()->getText( 'sort' );
 863                 if ( !array_key_exists( $this->mSort, $this->getFieldNames() ) ) {
 864                         $this->mSort = $this->getDefaultSort();
 865                 }
 866                 if ( $this->getRequest()->getBool( 'asc' ) ) {
 867                         $this->mDefaultDirection = false;
 868                 } elseif ( $this->getRequest()->getBool( 'desc' ) ) {
 869                         $this->mDefaultDirection = true;
 870                 } /* Else leave it at whatever the class default is */
 871
 872                 parent::__construct();
 873         }
 874
 875         /**
 876          * @protected
 877          * @return string
 878          */
 879         function getStartBody() {
 880                 global $wgStylePath;
 881                 $tableClass = htmlspecialchars( $this->getTableClass() );
 882                 $sortClass = htmlspecialchars( $this->getSortHeaderClass() );
 883
 884                 $s = "<table style='border:1;' class=\"mw-datatable $tableClass\"><thead><tr>\n";
 885                 $fields = $this->getFieldNames();
 886
 887                 # Make table header
 888                 foreach ( $fields as $field => $name ) {
 889                         if ( strval( $name ) == '' ) {
 890                                 $s .= "<th>&#160;</th>\n";
 891                         } elseif ( $this->isFieldSortable( $field ) ) {
 892                                 $query = array( 'sort' => $field, 'limit' => $this->mLimit );
 893                                 if ( $field == $this->mSort ) {
 894                                         # This is the sorted column
 895                                         # Prepare a link that goes in the other sort order
 896                                         if ( $this->mDefaultDirection ) {
 897                                                 # Descending
 898                                                 $image = 'Arr_d.png';
 899                                                 $query['asc'] = '1';
 900                                                 $query['desc'] = '';
 901                                                 $alt = htmlspecialchars( wfMsg( 'descending_abbrev' ) );
 902                                         } else {
 903                                                 # Ascending
 904                                                 $image = 'Arr_u.png';
 905                                                 $query['asc'] = '';
 906                                                 $query['desc'] = '1';
 907                                                 $alt = htmlspecialchars( wfMsg( 'ascending_abbrev' ) );
 908                                         }
 909                                         $image = htmlspecialchars( "$wgStylePath/common/images/$image" );
 910                                         $link = $this->makeLink(
 911                                                 "<img width=\"12\" height=\"12\" alt=\"$alt\" src=\"$image\" />" .
 912                                                         htmlspecialchars( $name ), $query );
 913                                         $s .= "<th class=\"$sortClass\">$link</th>\n";
 914                                 } else {
 915                                         $s .= '<th>' . $this->makeLink( htmlspecialchars( $name ), $query ) . "</th>\n";
 916                                 }
 917                         } else {
 918                                 $s .= '<th>' . htmlspecialchars( $name ) . "</th>\n";
 919                         }
 920                 }
 921                 $s .= "</tr></thead><tbody>\n";
 922                 return $s;
 923         }
 924
 925         /**
 926          * @protected
 927          * @return string
 928          */
 929         function getEndBody() {
 930                 return "</tbody></table>\n";
 931         }
 932
 933         /**
 934          * @protected
 935          * @return string
 936          */
 937         function getEmptyBody() {
 938                 $colspan = count( $this->getFieldNames() );
 939                 $msgEmpty = wfMsgHtml( 'table_pager_empty' );
 940                 return "<tr><td colspan=\"$colspan\">$msgEmpty</td></tr>\n";
 941         }
 942
 943         /**
 944          * @protected
 945          * @param stdClass $row
 946          * @return String HTML
 947          */
 948         function formatRow( $row ) {
 949                 $this->mCurrentRow = $row; // In case formatValue etc need to know
 950                 $s = Xml::openElement( 'tr', $this->getRowAttrs( $row ) );
 951                 $fieldNames = $this->getFieldNames();
 952
 953                 foreach ( $fieldNames as $field => $name ) {
 954                         $value = isset( $row->$field ) ? $row->$field : null;
 955                         $formatted = strval( $this->formatValue( $field, $value ) );
 956
 957                         if ( $formatted == '' ) {
 958                                 $formatted = '&#160;';
 959                         }
 960
 961                         $s .= Xml::tags( 'td', $this->getCellAttrs( $field, $value ), $formatted );
 962                 }
 963
 964                 $s .= "</tr>\n";
 965
 966                 return $s;
 967         }
 968
 969         /**
 970          * Get a class name to be applied to the given row.
 971          *
 972          * @protected
 973          *
 974          * @param $row Object: the database result row
 975          * @return String
 976          */
 977         function getRowClass( $row ) {
 978                 return '';
 979         }
 980
 981         /**
 982          * Get attributes to be applied to the given row.
 983          *
 984          * @protected
 985          *
 986          * @param $row Object: the database result row
 987          * @return Array of <attr> => <value>
 988          */
 989         function getRowAttrs( $row ) {
 990                 $class = $this->getRowClass( $row );
 991                 if ( $class === '' ) {
 992                         // Return an empty array to avoid clutter in HTML like class=""
 993                         return array();
 994                 } else {
 995                         return array( 'class' => $this->getRowClass( $row ) );
 996                 }
 997         }
 998
 999         /**
1000          * Get any extra attributes to be applied to the given cell. Don't
1001          * take this as an excuse to hardcode styles; use classes and
1002          * CSS instead.  Row context is available in $this->mCurrentRow
1003          *
1004          * @protected
1005          *
1006          * @param $field String The column
1007          * @param $value String The cell contents
1008          * @return Array of attr => value
1009          */
1010         function getCellAttrs( $field, $value ) {
1011                 return array( 'class' => 'TablePager_col_' . $field );
1012         }
1013
1014         /**
1015          * @protected
1016          * @return string
1017          */
1018         function getIndexField() {
1019                 return $this->mSort;
1020         }
1021
1022         /**
1023          * @protected
1024          * @return string
1025          */
1026         function getTableClass() {
1027                 return 'TablePager';
1028         }
1029
1030         /**
1031          * @protected
1032          * @return string
1033          */
1034         function getNavClass() {
1035                 return 'TablePager_nav';
1036         }
1037
1038         /**
1039          * @protected
1040          * @return string
1041          */
1042         function getSortHeaderClass() {
1043                 return 'TablePager_sort';
1044         }
1045
1046         /**
1047          * A navigation bar with images
1048          * @return String HTML
1049          */
1050         public function getNavigationBar() {
1051                 global $wgStylePath;
1052
1053                 if ( !$this->isNavigationBarShown() ) {
1054                         return '';
1055                 }
1056
1057                 $path = "$wgStylePath/common/images";
1058                 $labels = array(
1059                         'first' => 'table_pager_first',
1060                         'prev' => 'table_pager_prev',
1061                         'next' => 'table_pager_next',
1062                         'last' => 'table_pager_last',
1063                 );
1064                 $images = array(
1065                         'first' => 'arrow_first_25.png',
1066                         'prev' => 'arrow_left_25.png',
1067                         'next' => 'arrow_right_25.png',
1068                         'last' => 'arrow_last_25.png',
1069                 );
1070                 $disabledImages = array(
1071                         'first' => 'arrow_disabled_first_25.png',
1072                         'prev' => 'arrow_disabled_left_25.png',
1073                         'next' => 'arrow_disabled_right_25.png',
1074                         'last' => 'arrow_disabled_last_25.png',
1075                 );
1076                 if( $this->getLanguage()->isRTL() ) {
1077                         $keys = array_keys( $labels );
1078                         $images = array_combine( $keys, array_reverse( $images ) );
1079                         $disabledImages = array_combine( $keys, array_reverse( $disabledImages ) );
1080                 }
1081
1082                 $linkTexts = array();
1083                 $disabledTexts = array();
1084                 foreach ( $labels as $type => $label ) {
1085                         $msgLabel = wfMsgHtml( $label );
1086                         $linkTexts[$type] = "<img src=\"$path/{$images[$type]}\" alt=\"$msgLabel\"/><br />$msgLabel";
1087                         $disabledTexts[$type] = "<img src=\"$path/{$disabledImages[$type]}\" alt=\"$msgLabel\"/><br />$msgLabel";
1088                 }
1089                 $links = $this->getPagingLinks( $linkTexts, $disabledTexts );
1090
1091                 $navClass = htmlspecialchars( $this->getNavClass() );
1092                 $s = "<table class=\"$navClass\"><tr>\n";
1093                 $width = 100 / count( $links ) . '%';
1094                 foreach ( $labels as $type => $label ) {
1095                         $s .= "<td style='width:$width;'>{$links[$type]}</td>\n";
1096                 }
1097                 $s .= "</tr></table>\n";
1098                 return $s;
1099         }
1100
1101         /**
1102          * Get a <select> element which has options for each of the allowed limits
1103          *
1104          * @return String: HTML fragment
1105          */
1106         public function getLimitSelect() {
1107                 # Add the current limit from the query string
1108                 # to avoid that the limit is lost after clicking Go next time
1109                 if ( !in_array( $this->mLimit, $this->mLimitsShown ) ) {
1110                         $this->mLimitsShown[] = $this->mLimit;
1111                         sort( $this->mLimitsShown );
1112                 }
1113                 $s = Html::openElement( 'select', array( 'name' => 'limit' ) ) . "\n";
1114                 foreach ( $this->mLimitsShown as $key => $value ) {
1115                         # The pair is either $index => $limit, in which case the $value
1116                         # will be numeric, or $limit => $text, in which case the $value
1117                         # will be a string.
1118                         if( is_int( $value ) ){
1119                                 $limit = $value;
1120                                 $text = $this->getLanguage()->formatNum( $limit );
1121                         } else {
1122                                 $limit = $key;
1123                                 $text = $value;
1124                         }
1125                         $s .= Xml::option( $text, $limit, $limit == $this->mLimit ) . "\n";
1126                 }
1127                 $s .= Html::closeElement( 'select' );
1128                 return $s;
1129         }
1130
1131         /**
1132          * Get <input type="hidden"> elements for use in a method="get" form.
1133          * Resubmits all defined elements of the query string, except for a
1134          * blacklist, passed in the $blacklist parameter.
1135          *
1136          * @param $blacklist Array parameters from the request query which should not be resubmitted
1137          * @return String: HTML fragment
1138          */
1139         function getHiddenFields( $blacklist = array() ) {
1140                 $blacklist = (array)$blacklist;
1141                 $query = $this->getRequest()->getQueryValues();
1142                 foreach ( $blacklist as $name ) {
1143                         unset( $query[$name] );
1144                 }
1145                 $s = '';
1146                 foreach ( $query as $name => $value ) {
1147                         $encName = htmlspecialchars( $name );
1148                         $encValue = htmlspecialchars( $value );
1149                         $s .= "<input type=\"hidden\" name=\"$encName\" value=\"$encValue\"/>\n";
1150                 }
1151                 return $s;
1152         }
1153
1154         /**
1155          * Get a form containing a limit selection dropdown
1156          *
1157          * @return String: HTML fragment
1158          */
1159         function getLimitForm() {
1160                 global $wgScript;
1161
1162                 return Xml::openElement(
1163                         'form',
1164                         array(
1165                                 'method' => 'get',
1166                                 'action' => $wgScript
1167                         ) ) . "\n" . $this->getLimitDropdown() . "</form>\n";
1168         }
1169
1170         /**
1171          * Gets a limit selection dropdown
1172          *
1173          * @return string
1174          */
1175         function getLimitDropdown() {
1176                 # Make the select with some explanatory text
1177                 $msgSubmit = wfMsgHtml( 'table_pager_limit_submit' );
1178
1179                 return wfMsgHtml( 'table_pager_limit', $this->getLimitSelect() ) .
1180                         "\n<input type=\"submit\" value=\"$msgSubmit\"/>\n" .
1181                         $this->getHiddenFields( array( 'limit' ) );
1182         }
1183
1184         /**
1185          * Return true if the named field should be sortable by the UI, false
1186          * otherwise
1187          *
1188          * @param $field String
1189          */
1190         abstract function isFieldSortable( $field );
1191
1192         /**
1193          * Format a table cell. The return value should be HTML, but use an empty
1194          * string not &#160; for empty cells. Do not include the <td> and </td>.
1195          *
1196          * The current result row is available as $this->mCurrentRow, in case you
1197          * need more context.
1198          *
1199          * @protected
1200          *
1201          * @param $name String: the database field name
1202          * @param $value String: the value retrieved from the database
1203          */
1204         abstract function formatValue( $name, $value );
1205
1206         /**
1207          * The database field name used as a default sort order.
1208          *
1209          * @protected
1210          *
1211          * @return string
1212          */
1213         abstract function getDefaultSort();
1214
1215         /**
1216          * An array mapping database field names to a textual description of the
1217          * field name, for use in the table header. The description should be plain
1218          * text, it will be HTML-escaped later.
1219          *
1220          * @return Array
1221          */
1222         abstract function getFieldNames();
1223 }