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                 # Do any special query batches before display
 333                 $this->doBatchLookups();
 334
 335                 # Don't use any extra rows returned by the query
 336                 $numRows = min( $this->mResult->numRows(), $this->mLimit );
 337
 338                 $s = $this->getStartBody();
 339                 if ( $numRows ) {
 340                         if ( $this->mIsBackwards ) {
 341                                 for ( $i = $numRows - 1; $i >= 0; $i-- ) {
 342                                         $this->mResult->seek( $i );
 343                                         $row = $this->mResult->fetchObject();
 344                                         $s .= $this->formatRow( $row );
 345                                 }
 346                         } else {
 347                                 $this->mResult->seek( 0 );
 348                                 for ( $i = 0; $i < $numRows; $i++ ) {
 349                                         $row = $this->mResult->fetchObject();
 350                                         $s .= $this->formatRow( $row );
 351                                 }
 352                         }
 353                 } else {
 354                         $s .= $this->getEmptyBody();
 355                 }
 356                 $s .= $this->getEndBody();
 357                 return $s;
 358         }
 359
 360         /**
 361          * Make a self-link
 362          *
 363          * @param $text String: text displayed on the link
 364          * @param $query Array: associative array of paramter to be in the query string
 365          * @param $type String: value of the "rel" attribute
 366          * @return String: HTML fragment
 367          */
 368         function makeLink($text, $query = null, $type=null) {
 369                 if ( $query === null ) {
 370                         return $text;
 371                 }
 372
 373                 $attrs = array();
 374                 if( in_array( $type, array( 'first', 'prev', 'next', 'last' ) ) ) {
 375                         # HTML5 rel attributes
 376                         $attrs['rel'] = $type;
 377                 }
 378
 379                 if( $type ) {
 380                         $attrs['class'] = "mw-{$type}link";
 381                 }
 382                 return Linker::linkKnown(
 383                         $this->getTitle(),
 384                         $text,
 385                         $attrs,
 386                         $query + $this->getDefaultQuery()
 387                 );
 388         }
 389
 390         /**
 391          * Called from getBody(), before getStartBody() is called. This
 392          * will be called even if there are no rows in the result set.
 393          *
 394          * @return void
 395          */
 396         protected function doBatchLookups() {}
 397
 398         /**
 399          * Hook into getBody(), allows text to be inserted at the start. This
 400          * will be called even if there are no rows in the result set.
 401          *
 402          * @return String
 403          */
 404         protected function getStartBody() {
 405                 return '';
 406         }
 407
 408         /**
 409          * Hook into getBody() for the end of the list
 410          *
 411          * @return String
 412          */
 413         protected function getEndBody() {
 414                 return '';
 415         }
 416
 417         /**
 418          * Hook into getBody(), for the bit between the start and the
 419          * end when there are no rows
 420          *
 421          * @return String
 422          */
 423         protected function getEmptyBody() {
 424                 return '';
 425         }
 426
 427         /**
 428          * Get an array of query parameters that should be put into self-links.
 429          * By default, all parameters passed in the URL are used, except for a
 430          * short blacklist.
 431          *
 432          * @return Associative array
 433          */
 434         function getDefaultQuery() {
 435                 if ( !isset( $this->mDefaultQuery ) ) {
 436                         $this->mDefaultQuery = $this->getRequest()->getQueryValues();
 437                         unset( $this->mDefaultQuery['title'] );
 438                         unset( $this->mDefaultQuery['dir'] );
 439                         unset( $this->mDefaultQuery['offset'] );
 440                         unset( $this->mDefaultQuery['limit'] );
 441                         unset( $this->mDefaultQuery['order'] );
 442                         unset( $this->mDefaultQuery['month'] );
 443                         unset( $this->mDefaultQuery['year'] );
 444                 }
 445                 return $this->mDefaultQuery;
 446         }
 447
 448         /**
 449          * Get the number of rows in the result set
 450          *
 451          * @return Integer
 452          */
 453         function getNumRows() {
 454                 if ( !$this->mQueryDone ) {
 455                         $this->doQuery();
 456                 }
 457                 return $this->mResult->numRows();
 458         }
 459
 460         /**
 461          * Get a URL query array for the prev, next, first and last links.
 462          *
 463          * @return Array
 464          */
 465         function getPagingQueries() {
 466                 if ( !$this->mQueryDone ) {
 467                         $this->doQuery();
 468                 }
 469
 470                 # Don't announce the limit everywhere if it's the default
 471                 $urlLimit = $this->mLimit == $this->mDefaultLimit ? '' : $this->mLimit;
 472
 473                 if ( $this->mIsFirst ) {
 474                         $prev = false;
 475                         $first = false;
 476                 } else {
 477                         $prev = array(
 478                                 'dir' => 'prev',
 479                                 'offset' => $this->mFirstShown,
 480                                 'limit' => $urlLimit
 481                         );
 482                         $first = array( 'limit' => $urlLimit );
 483                 }
 484                 if ( $this->mIsLast ) {
 485                         $next = false;
 486                         $last = false;
 487                 } else {
 488                         $next = array( 'offset' => $this->mLastShown, 'limit' => $urlLimit );
 489                         $last = array( 'dir' => 'prev', 'limit' => $urlLimit );
 490                 }
 491                 return array(
 492                         'prev' => $prev,
 493                         'next' => $next,
 494                         'first' => $first,
 495                         'last' => $last
 496                 );
 497         }
 498
 499         /**
 500          * Returns whether to show the "navigation bar"
 501          *
 502          * @return Boolean
 503          */
 504         function isNavigationBarShown() {
 505                 if ( !$this->mQueryDone ) {
 506                         $this->doQuery();
 507                 }
 508                 // Hide navigation by default if there is nothing to page
 509                 return !($this->mIsFirst && $this->mIsLast);
 510         }
 511
 512         /**
 513          * Get paging links. If a link is disabled, the item from $disabledTexts
 514          * will be used. If there is no such item, the unlinked text from
 515          * $linkTexts will be used. Both $linkTexts and $disabledTexts are arrays
 516          * of HTML.
 517          *
 518          * @param $linkTexts Array
 519          * @param $disabledTexts Array
 520          * @return Array
 521          */
 522         function getPagingLinks( $linkTexts, $disabledTexts = array() ) {
 523                 $queries = $this->getPagingQueries();
 524                 $links = array();
 525                 foreach ( $queries as $type => $query ) {
 526                         if ( $query !== false ) {
 527                                 $links[$type] = $this->makeLink(
 528                                         $linkTexts[$type],
 529                                         $queries[$type],
 530                                         $type
 531                                 );
 532                         } elseif ( isset( $disabledTexts[$type] ) ) {
 533                                 $links[$type] = $disabledTexts[$type];
 534                         } else {
 535                                 $links[$type] = $linkTexts[$type];
 536                         }
 537                 }
 538                 return $links;
 539         }
 540
 541         function getLimitLinks() {
 542                 $links = array();
 543                 if ( $this->mIsBackwards ) {
 544                         $offset = $this->mPastTheEndIndex;
 545                 } else {
 546                         $offset = $this->mOffset;
 547                 }
 548                 foreach ( $this->mLimitsShown as $limit ) {
 549                         $links[] = $this->makeLink(
 550                                 $this->getLang()->formatNum( $limit ),
 551                                 array( 'offset' => $offset, 'limit' => $limit ),
 552                                 'num'
 553                         );
 554                 }
 555                 return $links;
 556         }
 557
 558         /**
 559          * Abstract formatting function. This should return an HTML string
 560          * representing the result row $row. Rows will be concatenated and
 561          * returned by getBody()
 562          *
 563          * @param $row Object: database row
 564          * @return String
 565          */
 566         abstract function formatRow( $row );
 567
 568         /**
 569          * This function should be overridden to provide all parameters
 570          * needed for the main paged query. It returns an associative
 571          * array with the following elements:
 572          *    tables => Table(s) for passing to Database::select()
 573          *    fields => Field(s) for passing to Database::select(), may be *
 574          *    conds => WHERE conditions
 575          *    options => option array
 576          *    join_conds => JOIN conditions
 577          *
 578          * @return Array
 579          */
 580         abstract function getQueryInfo();
 581
 582         /**
 583          * This function should be overridden to return the name of the index fi-
 584          * eld.  If the pager supports multiple orders, it may return an array of
 585          * 'querykey' => 'indexfield' pairs, so that a request with &count=querykey
 586          * will use indexfield to sort.  In this case, the first returned key is
 587          * the default.
 588          *
 589          * Needless to say, it's really not a good idea to use a non-unique index
 590          * for this!  That won't page right.
 591          *
 592          * @return string|Array
 593          */
 594         abstract function getIndexField();
 595
 596         /**
 597          * This function should be overridden to return the names of secondary columns
 598          * to order by in addition to the column in getIndexField(). These fields will
 599          * not be used in the pager offset or in any links for users.
 600          *
 601          * If getIndexField() returns an array of 'querykey' => 'indexfield' pairs then
 602          * this must return a corresponding array of 'querykey' => array( fields...) pairs
 603          * in order for a request with &count=querykey to use array( fields...) to sort.
 604          *
 605          * This is useful for pagers that GROUP BY a unique column (say page_id)
 606          * and ORDER BY another (say page_len). Using GROUP BY and ORDER BY both on
 607          * page_len,page_id avoids temp tables (given a page_len index). This would
 608          * also work if page_id was non-unique but we had a page_len,page_id index.
 609          *
 610          * @return Array
 611          */
 612         protected function getExtraSortFields() { return array(); }
 613
 614         /**
 615          * Return the default sorting direction: false for ascending, true for de-
 616          * scending.  You can also have an associative array of ordertype => dir,
 617          * if multiple order types are supported.  In this case getIndexField()
 618          * must return an array, and the keys of that must exactly match the keys
 619          * of this.
 620          *
 621          * For backward compatibility, this method's return value will be ignored
 622          * if $this->mDefaultDirection is already set when the constructor is
 623          * called, for instance if it's statically initialized.  In that case the
 624          * value of that variable (which must be a boolean) will be used.
 625          *
 626          * Note that despite its name, this does not return the value of the
 627          * $this->mDefaultDirection member variable.  That's the default for this
 628          * particular instantiation, which is a single value.  This is the set of
 629          * all defaults for the class.
 630          *
 631          * @return Boolean
 632          */
 633         protected function getDefaultDirections() { return false; }
 634 }
 635
 636
 637 /**
 638  * IndexPager with an alphabetic list and a formatted navigation bar
 639  * @ingroup Pager
 640  */
 641 abstract class AlphabeticPager extends IndexPager {
 642
 643         /**
 644          * Shamelessly stolen bits from ReverseChronologicalPager,
 645          * didn't want to do class magic as may be still revamped
 646          *
 647          * @return String HTML
 648          */
 649         function getNavigationBar() {
 650                 if ( !$this->isNavigationBarShown() ) return '';
 651
 652                 if( isset( $this->mNavigationBar ) ) {
 653                         return $this->mNavigationBar;
 654                 }
 655
 656                 $lang = $this->getLang();
 657
 658                 $opts = array( 'parsemag', 'escapenoentities' );
 659                 $linkTexts = array(
 660                         'prev' => wfMsgExt(
 661                                 'prevn',
 662                                 $opts,
 663                                 $lang->formatNum( $this->mLimit )
 664                         ),
 665                         'next' => wfMsgExt(
 666                                 'nextn',
 667                                 $opts,
 668                                 $lang->formatNum($this->mLimit )
 669                         ),
 670                         'first' => wfMsgExt( 'page_first', $opts ),
 671                         'last' => wfMsgExt( 'page_last', $opts )
 672                 );
 673
 674                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 675                 $limitLinks = $this->getLimitLinks();
 676                 $limits = $lang->pipeList( $limitLinks );
 677
 678                 $this->mNavigationBar =
 679                         "(" . $lang->pipeList(
 680                                 array( $pagingLinks['first'],
 681                                 $pagingLinks['last'] )
 682                         ) . ") " .
 683                         wfMsgHtml( 'viewprevnext', $pagingLinks['prev'],
 684                         $pagingLinks['next'], $limits );
 685
 686                 if( !is_array( $this->getIndexField() ) ) {
 687                         # Early return to avoid undue nesting
 688                         return $this->mNavigationBar;
 689                 }
 690
 691                 $extra = '';
 692                 $first = true;
 693                 $msgs = $this->getOrderTypeMessages();
 694                 foreach( array_keys( $msgs ) as $order ) {
 695                         if( $first ) {
 696                                 $first = false;
 697                         } else {
 698                                 $extra .= wfMsgExt( 'pipe-separator' , 'escapenoentities' );
 699                         }
 700
 701                         if( $order == $this->mOrderType ) {
 702                                 $extra .= wfMsgHTML( $msgs[$order] );
 703                         } else {
 704                                 $extra .= $this->makeLink(
 705                                         wfMsgHTML( $msgs[$order] ),
 706                                         array( 'order' => $order )
 707                                 );
 708                         }
 709                 }
 710
 711                 if( $extra !== '' ) {
 712                         $this->mNavigationBar .= " ($extra)";
 713                 }
 714
 715                 return $this->mNavigationBar;
 716         }
 717
 718         /**
 719          * If this supports multiple order type messages, give the message key for
 720          * enabling each one in getNavigationBar.  The return type is an associa-
 721          * tive array whose keys must exactly match the keys of the array returned
 722          * by getIndexField(), and whose values are message keys.
 723          *
 724          * @return Array
 725          */
 726         protected function getOrderTypeMessages() {
 727                 return null;
 728         }
 729 }
 730
 731 /**
 732  * IndexPager with a formatted navigation bar
 733  * @ingroup Pager
 734  */
 735 abstract class ReverseChronologicalPager extends IndexPager {
 736         public $mDefaultDirection = true;
 737         public $mYear;
 738         public $mMonth;
 739
 740         function getNavigationBar() {
 741                 if ( !$this->isNavigationBarShown() ) {
 742                         return '';
 743                 }
 744
 745                 if ( isset( $this->mNavigationBar ) ) {
 746                         return $this->mNavigationBar;
 747                 }
 748
 749                 $nicenumber = $this->getLang()->formatNum( $this->mLimit );
 750                 $linkTexts = array(
 751                         'prev' => wfMsgExt(
 752                                 'pager-newer-n',
 753                                 array( 'parsemag', 'escape' ),
 754                                 $nicenumber
 755                         ),
 756                         'next' => wfMsgExt(
 757                                 'pager-older-n',
 758                                 array( 'parsemag', 'escape' ),
 759                                 $nicenumber
 760                         ),
 761                         'first' => wfMsgHtml( 'histlast' ),
 762                         'last' => wfMsgHtml( 'histfirst' )
 763                 );
 764
 765                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 766                 $limitLinks = $this->getLimitLinks();
 767                 $limits = $this->getLang()->pipeList( $limitLinks );
 768
 769                 $this->mNavigationBar = "({$pagingLinks['first']}" .
 770                         wfMsgExt( 'pipe-separator' , 'escapenoentities' ) .
 771                         "{$pagingLinks['last']}) " .
 772                         wfMsgHTML(
 773                                 'viewprevnext',
 774                                 $pagingLinks['prev'], $pagingLinks['next'],
 775                                 $limits
 776                         );
 777                 return $this->mNavigationBar;
 778         }
 779
 780         function getDateCond( $year, $month ) {
 781                 $year = intval($year);
 782                 $month = intval($month);
 783                 // Basic validity checks
 784                 $this->mYear = $year > 0 ? $year : false;
 785                 $this->mMonth = ($month > 0 && $month < 13) ? $month : false;
 786                 // Given an optional year and month, we need to generate a timestamp
 787                 // to use as "WHERE rev_timestamp <= result"
 788                 // Examples: year = 2006 equals < 20070101 (+000000)
 789                 // year=2005, month=1    equals < 20050201
 790                 // year=2005, month=12   equals < 20060101
 791                 if ( !$this->mYear && !$this->mMonth ) {
 792                         return;
 793                 }
 794                 if ( $this->mYear ) {
 795                         $year = $this->mYear;
 796                 } else {
 797                         // If no year given, assume the current one
 798                         $year = gmdate( 'Y' );
 799                         // If this month hasn't happened yet this year, go back to last year's month
 800                         if( $this->mMonth > gmdate( 'n' ) ) {
 801                                 $year--;
 802                         }
 803                 }
 804                 if ( $this->mMonth ) {
 805                         $month = $this->mMonth + 1;
 806                         // For December, we want January 1 of the next year
 807                         if ($month > 12) {
 808                                 $month = 1;
 809                                 $year++;
 810                         }
 811                 } else {
 812                         // No month implies we want up to the end of the year in question
 813                         $month = 1;
 814                         $year++;
 815                 }
 816                 // Y2K38 bug
 817                 if ( $year > 2032 ) {
 818                         $year = 2032;
 819                 }
 820                 $ymd = (int)sprintf( "%04d%02d01", $year, $month );
 821                 if ( $ymd > 20320101 ) {
 822                         $ymd = 20320101;
 823                 }
 824                 $this->mOffset = $this->mDb->timestamp( "${ymd}000000" );
 825         }
 826 }
 827
 828 /**
 829  * Table-based display with a user-selectable sort order
 830  * @ingroup Pager
 831  */
 832 abstract class TablePager extends IndexPager {
 833         var $mSort;
 834         var $mCurrentRow;
 835
 836         function __construct( IContextSource $context = null ) {
 837                 if ( $context ) {
 838                         $this->setContext( $context );
 839                 }
 840
 841                 $this->mSort = $this->getRequest()->getText( 'sort' );
 842                 if ( !array_key_exists( $this->mSort, $this->getFieldNames() ) ) {
 843                         $this->mSort = $this->getDefaultSort();
 844                 }
 845                 if ( $this->getRequest()->getBool( 'asc' ) ) {
 846                         $this->mDefaultDirection = false;
 847                 } elseif ( $this->getRequest()->getBool( 'desc' ) ) {
 848                         $this->mDefaultDirection = true;
 849                 } /* Else leave it at whatever the class default is */
 850
 851                 parent::__construct();
 852         }
 853
 854         function getStartBody() {
 855                 global $wgStylePath;
 856                 $tableClass = htmlspecialchars( $this->getTableClass() );
 857                 $sortClass = htmlspecialchars( $this->getSortHeaderClass() );
 858
 859                 $s = "<table style='border:1;' class=\"mw-datatable $tableClass\"><thead><tr>\n";
 860                 $fields = $this->getFieldNames();
 861
 862                 # Make table header
 863                 foreach ( $fields as $field => $name ) {
 864                         if ( strval( $name ) == '' ) {
 865                                 $s .= "<th>&#160;</th>\n";
 866                         } elseif ( $this->isFieldSortable( $field ) ) {
 867                                 $query = array( 'sort' => $field, 'limit' => $this->mLimit );
 868                                 if ( $field == $this->mSort ) {
 869                                         # This is the sorted column
 870                                         # Prepare a link that goes in the other sort order
 871                                         if ( $this->mDefaultDirection ) {
 872                                                 # Descending
 873                                                 $image = 'Arr_d.png';
 874                                                 $query['asc'] = '1';
 875                                                 $query['desc'] = '';
 876                                                 $alt = htmlspecialchars( wfMsg( 'descending_abbrev' ) );
 877                                         } else {
 878                                                 # Ascending
 879                                                 $image = 'Arr_u.png';
 880                                                 $query['asc'] = '';
 881                                                 $query['desc'] = '1';
 882                                                 $alt = htmlspecialchars( wfMsg( 'ascending_abbrev' ) );
 883                                         }
 884                                         $image = htmlspecialchars( "$wgStylePath/common/images/$image" );
 885                                         $link = $this->makeLink(
 886                                                 "<img width=\"12\" height=\"12\" alt=\"$alt\" src=\"$image\" />" .
 887                                                 htmlspecialchars( $name ), $query );
 888                                         $s .= "<th class=\"$sortClass\">$link</th>\n";
 889                                 } else {
 890                                         $s .= '<th>' . $this->makeLink( htmlspecialchars( $name ), $query ) . "</th>\n";
 891                                 }
 892                         } else {
 893                                 $s .= '<th>' . htmlspecialchars( $name ) . "</th>\n";
 894                         }
 895                 }
 896                 $s .= "</tr></thead><tbody>\n";
 897                 return $s;
 898         }
 899
 900         function getEndBody() {
 901                 return "</tbody></table>\n";
 902         }
 903
 904         function getEmptyBody() {
 905                 $colspan = count( $this->getFieldNames() );
 906                 $msgEmpty = wfMsgHtml( 'table_pager_empty' );
 907                 return "<tr><td colspan=\"$colspan\">$msgEmpty</td></tr>\n";
 908         }
 909
 910         /**
 911          * @param $row Array
 912          * @return String HTML
 913          */
 914         function formatRow( $row ) {
 915                 $this->mCurrentRow = $row;      # In case formatValue etc need to know
 916                 $s = Xml::openElement( 'tr', $this->getRowAttrs( $row ) );
 917                 $fieldNames = $this->getFieldNames();
 918                 foreach ( $fieldNames as $field => $name ) {
 919                         $value = isset( $row->$field ) ? $row->$field : null;
 920                         $formatted = strval( $this->formatValue( $field, $value ) );
 921                         if ( $formatted == '' ) {
 922                                 $formatted = '&#160;';
 923                         }
 924                         $s .= Xml::tags( 'td', $this->getCellAttrs( $field, $value ), $formatted );
 925                 }
 926                 $s .= "</tr>\n";
 927                 return $s;
 928         }
 929
 930         /**
 931          * Get a class name to be applied to the given row.
 932          *
 933          * @param $row Object: the database result row
 934          * @return String
 935          */
 936         function getRowClass( $row ) {
 937                 return '';
 938         }
 939
 940         /**
 941          * Get attributes to be applied to the given row.
 942          *
 943          * @param $row Object: the database result row
 944          * @return Array of <attr> => <value>
 945          */
 946         function getRowAttrs( $row ) {
 947                 $class = $this->getRowClass( $row );
 948                 if ( $class === '' ) {
 949                         // Return an empty array to avoid clutter in HTML like class=""
 950                         return array();
 951                 } else {
 952                         return array( 'class' => $this->getRowClass( $row ) );
 953                 }
 954         }
 955
 956         /**
 957          * Get any extra attributes to be applied to the given cell. Don't
 958          * take this as an excuse to hardcode styles; use classes and
 959          * CSS instead.  Row context is available in $this->mCurrentRow
 960          *
 961          * @param $field String The column
 962          * @param $value String The cell contents
 963          * @return Array of attr => value
 964          */
 965         function getCellAttrs( $field, $value ) {
 966                 return array( 'class' => 'TablePager_col_' . $field );
 967         }
 968
 969         function getIndexField() {
 970                 return $this->mSort;
 971         }
 972
 973         function getTableClass() {
 974                 return 'TablePager';
 975         }
 976
 977         function getNavClass() {
 978                 return 'TablePager_nav';
 979         }
 980
 981         function getSortHeaderClass() {
 982                 return 'TablePager_sort';
 983         }
 984
 985         /**
 986          * A navigation bar with images
 987          * @return String HTML
 988          */
 989         function getNavigationBar() {
 990                 global $wgStylePath;
 991
 992                 if ( !$this->isNavigationBarShown() ) {
 993                         return '';
 994                 }
 995
 996                 $path = "$wgStylePath/common/images";
 997                 $labels = array(
 998                         'first' => 'table_pager_first',
 999                         'prev' => 'table_pager_prev',
1000                         'next' => 'table_pager_next',
1001                         'last' => 'table_pager_last',
1002                 );
1003                 $images = array(
1004                         'first' => 'arrow_first_25.png',
1005                         'prev' => 'arrow_left_25.png',
1006                         'next' => 'arrow_right_25.png',
1007                         'last' => 'arrow_last_25.png',
1008                 );
1009                 $disabledImages = array(
1010                         'first' => 'arrow_disabled_first_25.png',
1011                         'prev' => 'arrow_disabled_left_25.png',
1012                         'next' => 'arrow_disabled_right_25.png',
1013                         'last' => 'arrow_disabled_last_25.png',
1014                 );
1015                 if( $this->getLang()->isRTL() ) {
1016                         $keys = array_keys( $labels );
1017                         $images = array_combine( $keys, array_reverse( $images ) );
1018                         $disabledImages = array_combine( $keys, array_reverse( $disabledImages ) );
1019                 }
1020
1021                 $linkTexts = array();
1022                 $disabledTexts = array();
1023                 foreach ( $labels as $type => $label ) {
1024                         $msgLabel = wfMsgHtml( $label );
1025                         $linkTexts[$type] = "<img src=\"$path/{$images[$type]}\" alt=\"$msgLabel\"/><br />$msgLabel";
1026                         $disabledTexts[$type] = "<img src=\"$path/{$disabledImages[$type]}\" alt=\"$msgLabel\"/><br />$msgLabel";
1027                 }
1028                 $links = $this->getPagingLinks( $linkTexts, $disabledTexts );
1029
1030                 $navClass = htmlspecialchars( $this->getNavClass() );
1031                 $s = "<table class=\"$navClass\"><tr>\n";
1032                 $width = 100 / count( $links ) . '%';
1033                 foreach ( $labels as $type => $label ) {
1034                         $s .= "<td style='width:$width;'>{$links[$type]}</td>\n";
1035                 }
1036                 $s .= "</tr></table>\n";
1037                 return $s;
1038         }
1039
1040         /**
1041          * Get a <select> element which has options for each of the allowed limits
1042          *
1043          * @return String: HTML fragment
1044          */
1045         function getLimitSelect() {
1046                 # Add the current limit from the query string
1047                 # to avoid that the limit is lost after clicking Go next time
1048                 if ( !in_array( $this->mLimit, $this->mLimitsShown ) ) {
1049                         $this->mLimitsShown[] = $this->mLimit;
1050                         sort( $this->mLimitsShown );
1051                 }
1052                 $s = Html::openElement( 'select', array( 'name' => 'limit' ) ) . "\n";
1053                 foreach ( $this->mLimitsShown as $key => $value ) {
1054                         # The pair is either $index => $limit, in which case the $value
1055                         # will be numeric, or $limit => $text, in which case the $value
1056                         # will be a string.
1057                         if( is_int( $value ) ){
1058                                 $limit = $value;
1059                                 $text = $this->getLang()->formatNum( $limit );
1060                         } else {
1061                                 $limit = $key;
1062                                 $text = $value;
1063                         }
1064                         $s .= Xml::option( $text, $limit, $limit == $this->mLimit ) . "\n";
1065                 }
1066                 $s .= Html::closeElement( 'select' );
1067                 return $s;
1068         }
1069
1070         /**
1071          * Get <input type="hidden"> elements for use in a method="get" form.
1072          * Resubmits all defined elements of the query string, except for a
1073          * blacklist, passed in the $blacklist parameter.
1074          *
1075          * @param $blacklist Array parameters from the request query which should not be resubmitted
1076          * @return String: HTML fragment
1077          */
1078         function getHiddenFields( $blacklist = array() ) {
1079                 $blacklist = (array)$blacklist;
1080                 $query = $this->getRequest()->getQueryValues();
1081                 foreach ( $blacklist as $name ) {
1082                         unset( $query[$name] );
1083                 }
1084                 $s = '';
1085                 foreach ( $query as $name => $value ) {
1086                         $encName = htmlspecialchars( $name );
1087                         $encValue = htmlspecialchars( $value );
1088                         $s .= "<input type=\"hidden\" name=\"$encName\" value=\"$encValue\"/>\n";
1089                 }
1090                 return $s;
1091         }
1092
1093         /**
1094          * Get a form containing a limit selection dropdown
1095          *
1096          * @return String: HTML fragment
1097          */
1098         function getLimitForm() {
1099                 global $wgScript;
1100
1101                 return Xml::openElement(
1102                         'form',
1103                         array(
1104                                 'method' => 'get',
1105                                 'action' => $wgScript
1106                         ) ) . "\n" . $this->getLimitDropdown() . "</form>\n";
1107         }
1108
1109         /**
1110          * Gets a limit selection dropdown
1111          *
1112          * @return string
1113          */
1114         function getLimitDropdown() {
1115                 # Make the select with some explanatory text
1116                 $msgSubmit = wfMsgHtml( 'table_pager_limit_submit' );
1117
1118                 return wfMsgHtml( 'table_pager_limit', $this->getLimitSelect() ) .
1119                         "\n<input type=\"submit\" value=\"$msgSubmit\"/>\n" .
1120                         $this->getHiddenFields( array( 'limit' ) );
1121         }
1122
1123         /**
1124          * Return true if the named field should be sortable by the UI, false
1125          * otherwise
1126          *
1127          * @param $field String
1128          */
1129         abstract function isFieldSortable( $field );
1130
1131         /**
1132          * Format a table cell. The return value should be HTML, but use an empty
1133          * string not &#160; for empty cells. Do not include the <td> and </td>.
1134          *
1135          * The current result row is available as $this->mCurrentRow, in case you
1136          * need more context.
1137          *
1138          * @param $name String: the database field name
1139          * @param $value String: the value retrieved from the database
1140          */
1141         abstract function formatValue( $name, $value );
1142
1143         /**
1144          * The database field name used as a default sort order
1145          */
1146         abstract function getDefaultSort();
1147
1148         /**
1149          * An array mapping database field names to a textual description of the
1150          * field name, for use in the table header. The description should be plain
1151          * text, it will be HTML-escaped later.
1152          *
1153          * @return Array
1154          */
1155         abstract function getFieldNames();
1156 }