includes/Pager.php

   1 <?php
   2 /**
   3  * @defgroup Pager Pager
   4  *
   5  * @file
   6  * @ingroup Pager
   7  */
   8
   9 /**
  10  * Basic pager interface.
  11  * @ingroup Pager
  12  */
  13 interface Pager {
  14         function getNavigationBar();
  15         function getBody();
  16 }
  17
  18 /**
  19  * IndexPager is an efficient pager which uses a (roughly unique) index in the
  20  * data set to implement paging, rather than a "LIMIT offset,limit" clause.
  21  * In MySQL, such a limit/offset clause requires counting through the
  22  * specified number of offset rows to find the desired data, which can be
  23  * expensive for large offsets.
  24  *
  25  * ReverseChronologicalPager is a child class of the abstract IndexPager, and
  26  * contains  some formatting and display code which is specific to the use of
  27  * timestamps as  indexes. Here is a synopsis of its operation:
  28  *
  29  *    * The query is specified by the offset, limit and direction (dir)
  30  *      parameters, in addition to any subclass-specific parameters.
  31  *    * The offset is the non-inclusive start of the DB query. A row with an
  32  *      index value equal to the offset will never be shown.
  33  *    * The query may either be done backwards, where the rows are returned by
  34  *      the database in the opposite order to which they are displayed to the
  35  *      user, or forwards. This is specified by the "dir" parameter, dir=prev
  36  *      means backwards, anything else means forwards. The offset value
  37  *      specifies the start of the database result set, which may be either
  38  *      the start or end of the displayed data set. This allows "previous"
  39  *      links to be implemented without knowledge of the index value at the
  40  *      start of the previous page.
  41  *    * An additional row beyond the user-specified limit is always requested.
  42  *      This allows us to tell whether we should display a "next" link in the
  43  *      case of forwards mode, or a "previous" link in the case of backwards
  44  *      mode. Determining whether to display the other link (the one for the
  45  *      page before the start of the database result set) can be done
  46  *      heuristically by examining the offset.
  47  *
  48  *    * An empty offset indicates that the offset condition should be omitted
  49  *      from the query. This naturally produces either the first page or the
  50  *      last page depending on the dir parameter.
  51  *
  52  *  Subclassing the pager to implement concrete functionality should be fairly
  53  *  simple, please see the examples in HistoryPage.php and
  54  *  SpecialBlockList.php. You just need to override formatRow(),
  55  *  getQueryInfo() and getIndexField(). Don't forget to call the parent
  56  *  constructor if you override it.
  57  *
  58  * @ingroup Pager
  59  */
  60 abstract class IndexPager extends ContextSource implements Pager {
  61         public $mRequest;
  62         public $mLimitsShown = array( 20, 50, 100, 250, 500 );
  63         public $mDefaultLimit = 50;
  64         public $mOffset, $mLimit;
  65         public $mQueryDone = false;
  66         public $mDb;
  67         public $mPastTheEndRow;
  68
  69         /**
  70          * The index to actually be used for ordering. This is a single column,
  71          * for one ordering, even if multiple orderings are supported.
  72          */
  73         protected $mIndexField;
  74         /**
  75          * An array of secondary columns to order by. These fields are not part of the offset.
  76          * This is a column list for one ordering, even if multiple orderings are supported.
  77          */
  78         protected $mExtraSortFields;
  79         /** For pages that support multiple types of ordering, which one to use.
  80          */
  81         protected $mOrderType;
  82         /**
  83          * $mDefaultDirection gives the direction to use when sorting results:
  84          * false for ascending, true for descending.  If $mIsBackwards is set, we
  85          * start from the opposite end, but we still sort the page itself according
  86          * to $mDefaultDirection.  E.g., if $mDefaultDirection is false but we're
  87          * going backwards, we'll display the last page of results, but the last
  88          * result will be at the bottom, not the top.
  89          *
  90          * Like $mIndexField, $mDefaultDirection will be a single value even if the
  91          * class supports multiple default directions for different order types.
  92          */
  93         public $mDefaultDirection;
  94         public $mIsBackwards;
  95
  96         /** True if the current result set is the first one */
  97         public $mIsFirst;
  98         public $mIsLast;
  99
 100         protected $mLastShown, $mFirstShown, $mPastTheEndIndex, $mDefaultQuery, $mNavigationBar;
 101
 102         /**
 103          * Result object for the query. Warning: seek before use.
 104          *
 105          * @var ResultWrapper
 106          */
 107         public $mResult;
 108
 109         public function __construct( IContextSource $context = null ) {
 110                 if ( $context ) {
 111                         $this->setContext( $context );
 112                 }
 113
 114                 $this->mRequest = $this->getRequest();
 115
 116                 # NB: the offset is quoted, not validated. It is treated as an
 117                 # arbitrary string to support the widest variety of index types. Be
 118                 # careful outputting it into HTML!
 119                 $this->mOffset = $this->mRequest->getText( 'offset' );
 120
 121                 # Use consistent behavior for the limit options
 122                 $this->mDefaultLimit = intval( $this->getUser()->getOption( 'rclimit' ) );
 123                 list( $this->mLimit, /* $offset */ ) = $this->mRequest->getLimitOffset();
 124
 125                 $this->mIsBackwards = ( $this->mRequest->getVal( 'dir' ) == 'prev' );
 126                 $this->mDb = wfGetDB( DB_SLAVE );
 127
 128                 $index = $this->getIndexField(); // column to sort on
 129                 $extraSort = $this->getExtraSortFields(); // extra columns to sort on for query planning
 130                 $order = $this->mRequest->getVal( 'order' );
 131                 if( is_array( $index ) && isset( $index[$order] ) ) {
 132                         $this->mOrderType = $order;
 133                         $this->mIndexField = $index[$order];
 134                         $this->mExtraSortFields = isset( $extraSort[$order] )
 135                                 ? (array)$extraSort[$order]
 136                                 : array();
 137                 } elseif( is_array( $index ) ) {
 138                         # First element is the default
 139                         reset( $index );
 140                         list( $this->mOrderType, $this->mIndexField ) = each( $index );
 141                         $this->mExtraSortFields = isset( $extraSort[$this->mOrderType] )
 142                                 ? (array)$extraSort[$this->mOrderType]
 143                                 : array();
 144                 } else {
 145                         # $index is not an array
 146                         $this->mOrderType = null;
 147                         $this->mIndexField = $index;
 148                         $this->mExtraSortFields = (array)$extraSort;
 149                 }
 150
 151                 if( !isset( $this->mDefaultDirection ) ) {
 152                         $dir = $this->getDefaultDirections();
 153                         $this->mDefaultDirection = is_array( $dir )
 154                                 ? $dir[$this->mOrderType]
 155                                 : $dir;
 156                 }
 157         }
 158
 159         /**
 160          * Do the query, using information from the object context. This function
 161          * has been kept minimal to make it overridable if necessary, to allow for
 162          * result sets formed from multiple DB queries.
 163          */
 164         public function doQuery() {
 165                 # Use the child class name for profiling
 166                 $fname = __METHOD__ . ' (' . get_class( $this ) . ')';
 167                 wfProfileIn( $fname );
 168
 169                 $descending = ( $this->mIsBackwards == $this->mDefaultDirection );
 170                 # Plus an extra row so that we can tell the "next" link should be shown
 171                 $queryLimit = $this->mLimit + 1;
 172
 173                 $this->mResult = $this->reallyDoQuery(
 174                         $this->mOffset,
 175                         $queryLimit,
 176                         $descending
 177                 );
 178                 $this->extractResultInfo( $this->mOffset, $queryLimit, $this->mResult );
 179                 $this->mQueryDone = true;
 180
 181                 $this->preprocessResults( $this->mResult );
 182                 $this->mResult->rewind(); // Paranoia
 183
 184                 wfProfileOut( $fname );
 185         }
 186
 187         /**
 188          * @return ResultWrapper The result wrapper.
 189          */
 190         function getResult() {
 191                 return $this->mResult;
 192         }
 193
 194         /**
 195          * Set the offset from an other source than the request
 196          *
 197          * @param $offset Int|String
 198          */
 199         function setOffset( $offset ) {
 200                 $this->mOffset = $offset;
 201         }
 202         /**
 203          * Set the limit from an other source than the request
 204          *
 205          * @param $limit Int|String
 206          */
 207         function setLimit( $limit ) {
 208                 $this->mLimit = $limit;
 209         }
 210
 211         /**
 212          * Extract some useful data from the result object for use by
 213          * the navigation bar, put it into $this
 214          *
 215          * @param $offset String: index offset, inclusive
 216          * @param $limit Integer: exact query limit
 217          * @param $res ResultWrapper
 218          */
 219         function extractResultInfo( $offset, $limit, ResultWrapper $res ) {
 220                 $numRows = $res->numRows();
 221                 if ( $numRows ) {
 222                         # Remove any table prefix from index field
 223                         $parts = explode( '.', $this->mIndexField );
 224                         $indexColumn = end( $parts );
 225
 226                         $row = $res->fetchRow();
 227                         $firstIndex = $row[$indexColumn];
 228
 229                         # Discard the extra result row if there is one
 230                         if ( $numRows > $this->mLimit && $numRows > 1 ) {
 231                                 $res->seek( $numRows - 1 );
 232                                 $this->mPastTheEndRow = $res->fetchObject();
 233                                 $indexField = $this->mIndexField;
 234                                 $this->mPastTheEndIndex = $this->mPastTheEndRow->$indexField;
 235                                 $res->seek( $numRows - 2 );
 236                                 $row = $res->fetchRow();
 237                                 $lastIndex = $row[$indexColumn];
 238                         } else {
 239                                 $this->mPastTheEndRow = null;
 240                                 # Setting indexes to an empty string means that they will be
 241                                 # omitted if they would otherwise appear in URLs. It just so
 242                                 # happens that this  is the right thing to do in the standard
 243                                 # UI, in all the relevant cases.
 244                                 $this->mPastTheEndIndex = '';
 245                                 $res->seek( $numRows - 1 );
 246                                 $row = $res->fetchRow();
 247                                 $lastIndex = $row[$indexColumn];
 248                         }
 249                 } else {
 250                         $firstIndex = '';
 251                         $lastIndex = '';
 252                         $this->mPastTheEndRow = null;
 253                         $this->mPastTheEndIndex = '';
 254                 }
 255
 256                 if ( $this->mIsBackwards ) {
 257                         $this->mIsFirst = ( $numRows < $limit );
 258                         $this->mIsLast = ( $offset == '' );
 259                         $this->mLastShown = $firstIndex;
 260                         $this->mFirstShown = $lastIndex;
 261                 } else {
 262                         $this->mIsFirst = ( $offset == '' );
 263                         $this->mIsLast = ( $numRows < $limit );
 264                         $this->mLastShown = $lastIndex;
 265                         $this->mFirstShown = $firstIndex;
 266                 }
 267         }
 268
 269         /**
 270          * Get some text to go in brackets in the "function name" part of the SQL comment
 271          *
 272          * @return String
 273          */
 274         function getSqlComment() {
 275                 return get_class( $this );
 276         }
 277
 278         /**
 279          * Do a query with specified parameters, rather than using the object
 280          * context
 281          *
 282          * @param $offset String: index offset, inclusive
 283          * @param $limit Integer: exact query limit
 284          * @param $descending Boolean: query direction, false for ascending, true for descending
 285          * @return ResultWrapper
 286          */
 287         function reallyDoQuery( $offset, $limit, $descending ) {
 288                 $fname = __METHOD__ . ' (' . $this->getSqlComment() . ')';
 289                 $info = $this->getQueryInfo();
 290                 $tables = $info['tables'];
 291                 $fields = $info['fields'];
 292                 $conds = isset( $info['conds'] ) ? $info['conds'] : array();
 293                 $options = isset( $info['options'] ) ? $info['options'] : array();
 294                 $join_conds = isset( $info['join_conds'] ) ? $info['join_conds'] : array();
 295                 $sortColumns = array_merge( array( $this->mIndexField ), $this->mExtraSortFields );
 296                 if ( $descending ) {
 297                         $options['ORDER BY'] = implode( ',', $sortColumns );
 298                         $operator = '>';
 299                 } else {
 300                         $orderBy = array();
 301                         foreach ( $sortColumns as $col ) {
 302                                 $orderBy[] = $col . ' DESC';
 303                         }
 304                         $options['ORDER BY'] = implode( ',', $orderBy );
 305                         $operator = '<';
 306                 }
 307                 if ( $offset != '' ) {
 308                         $conds[] = $this->mIndexField . $operator . $this->mDb->addQuotes( $offset );
 309                 }
 310                 $options['LIMIT'] = intval( $limit );
 311                 $res = $this->mDb->select( $tables, $fields, $conds, $fname, $options, $join_conds );
 312                 return new ResultWrapper( $this->mDb, $res );
 313         }
 314
 315         /**
 316          * Pre-process results; useful for performing batch existence checks, etc.
 317          *
 318          * @param $result ResultWrapper
 319          */
 320         protected function preprocessResults( $result ) {}
 321
 322         /**
 323          * Get the formatted result list. Calls getStartBody(), formatRow() and
 324          * getEndBody(), concatenates the results and returns them.
 325          *
 326          * @return String
 327          */
 328         public function getBody() {
 329                 if ( !$this->mQueryDone ) {
 330                         $this->doQuery();
 331                 }
 332
 333                 if ( $this->mResult->numRows() ) {
 334                         # Do any special query batches before display
 335                         $this->doBatchLookups();
 336                 }
 337
 338                 # Don't use any extra rows returned by the query
 339                 $numRows = min( $this->mResult->numRows(), $this->mLimit );
 340
 341                 $s = $this->getStartBody();
 342                 if ( $numRows ) {
 343                         if ( $this->mIsBackwards ) {
 344                                 for ( $i = $numRows - 1; $i >= 0; $i-- ) {
 345                                         $this->mResult->seek( $i );
 346                                         $row = $this->mResult->fetchObject();
 347                                         $s .= $this->formatRow( $row );
 348                                 }
 349                         } else {
 350                                 $this->mResult->seek( 0 );
 351                                 for ( $i = 0; $i < $numRows; $i++ ) {
 352                                         $row = $this->mResult->fetchObject();
 353                                         $s .= $this->formatRow( $row );
 354                                 }
 355                         }
 356                 } else {
 357                         $s .= $this->getEmptyBody();
 358                 }
 359                 $s .= $this->getEndBody();
 360                 return $s;
 361         }
 362
 363         /**
 364          * Make a self-link
 365          *
 366          * @param $text String: text displayed on the link
 367          * @param $query Array: associative array of paramter to be in the query string
 368          * @param $type String: value of the "rel" attribute
 369          * @return String: HTML fragment
 370          */
 371         function makeLink($text, $query = null, $type=null) {
 372                 if ( $query === null ) {
 373                         return $text;
 374                 }
 375
 376                 $attrs = array();
 377                 if( in_array( $type, array( 'first', 'prev', 'next', 'last' ) ) ) {
 378                         # HTML5 rel attributes
 379                         $attrs['rel'] = $type;
 380                 }
 381
 382                 if( $type ) {
 383                         $attrs['class'] = "mw-{$type}link";
 384                 }
 385                 return Linker::linkKnown(
 386                         $this->getTitle(),
 387                         $text,
 388                         $attrs,
 389                         $query + $this->getDefaultQuery()
 390                 );
 391         }
 392
 393         /**
 394          * Called from getBody(), before getStartBody() is called and
 395          * after doQuery() was called. This will be called only if there
 396          * are rows in the result set.
 397          *
 398          * @return void
 399          */
 400         protected function doBatchLookups() {}
 401
 402         /**
 403          * Hook into getBody(), allows text to be inserted at the start. This
 404          * will be called even if there are no rows in the result set.
 405          *
 406          * @return String
 407          */
 408         protected function getStartBody() {
 409                 return '';
 410         }
 411
 412         /**
 413          * Hook into getBody() for the end of the list
 414          *
 415          * @return String
 416          */
 417         protected function getEndBody() {
 418                 return '';
 419         }
 420
 421         /**
 422          * Hook into getBody(), for the bit between the start and the
 423          * end when there are no rows
 424          *
 425          * @return String
 426          */
 427         protected function getEmptyBody() {
 428                 return '';
 429         }
 430
 431         /**
 432          * Get an array of query parameters that should be put into self-links.
 433          * By default, all parameters passed in the URL are used, except for a
 434          * short blacklist.
 435          *
 436          * @return Associative array
 437          */
 438         function getDefaultQuery() {
 439                 if ( !isset( $this->mDefaultQuery ) ) {
 440                         $this->mDefaultQuery = $this->getRequest()->getQueryValues();
 441                         unset( $this->mDefaultQuery['title'] );
 442                         unset( $this->mDefaultQuery['dir'] );
 443                         unset( $this->mDefaultQuery['offset'] );
 444                         unset( $this->mDefaultQuery['limit'] );
 445                         unset( $this->mDefaultQuery['order'] );
 446                         unset( $this->mDefaultQuery['month'] );
 447                         unset( $this->mDefaultQuery['year'] );
 448                 }
 449                 return $this->mDefaultQuery;
 450         }
 451
 452         /**
 453          * Get the number of rows in the result set
 454          *
 455          * @return Integer
 456          */
 457         function getNumRows() {
 458                 if ( !$this->mQueryDone ) {
 459                         $this->doQuery();
 460                 }
 461                 return $this->mResult->numRows();
 462         }
 463
 464         /**
 465          * Get a URL query array for the prev, next, first and last links.
 466          *
 467          * @return Array
 468          */
 469         function getPagingQueries() {
 470                 if ( !$this->mQueryDone ) {
 471                         $this->doQuery();
 472                 }
 473
 474                 # Don't announce the limit everywhere if it's the default
 475                 $urlLimit = $this->mLimit == $this->mDefaultLimit ? '' : $this->mLimit;
 476
 477                 if ( $this->mIsFirst ) {
 478                         $prev = false;
 479                         $first = false;
 480                 } else {
 481                         $prev = array(
 482                                 'dir' => 'prev',
 483                                 'offset' => $this->mFirstShown,
 484                                 'limit' => $urlLimit
 485                         );
 486                         $first = array( 'limit' => $urlLimit );
 487                 }
 488                 if ( $this->mIsLast ) {
 489                         $next = false;
 490                         $last = false;
 491                 } else {
 492                         $next = array( 'offset' => $this->mLastShown, 'limit' => $urlLimit );
 493                         $last = array( 'dir' => 'prev', 'limit' => $urlLimit );
 494                 }
 495                 return array(
 496                         'prev' => $prev,
 497                         'next' => $next,
 498                         'first' => $first,
 499                         'last' => $last
 500                 );
 501         }
 502
 503         /**
 504          * Returns whether to show the "navigation bar"
 505          *
 506          * @return Boolean
 507          */
 508         function isNavigationBarShown() {
 509                 if ( !$this->mQueryDone ) {
 510                         $this->doQuery();
 511                 }
 512                 // Hide navigation by default if there is nothing to page
 513                 return !($this->mIsFirst && $this->mIsLast);
 514         }
 515
 516         /**
 517          * Get paging links. If a link is disabled, the item from $disabledTexts
 518          * will be used. If there is no such item, the unlinked text from
 519          * $linkTexts will be used. Both $linkTexts and $disabledTexts are arrays
 520          * of HTML.
 521          *
 522          * @param $linkTexts Array
 523          * @param $disabledTexts Array
 524          * @return Array
 525          */
 526         function getPagingLinks( $linkTexts, $disabledTexts = array() ) {
 527                 $queries = $this->getPagingQueries();
 528                 $links = array();
 529                 foreach ( $queries as $type => $query ) {
 530                         if ( $query !== false ) {
 531                                 $links[$type] = $this->makeLink(
 532                                         $linkTexts[$type],
 533                                         $queries[$type],
 534                                         $type
 535                                 );
 536                         } elseif ( isset( $disabledTexts[$type] ) ) {
 537                                 $links[$type] = $disabledTexts[$type];
 538                         } else {
 539                                 $links[$type] = $linkTexts[$type];
 540                         }
 541                 }
 542                 return $links;
 543         }
 544
 545         function getLimitLinks() {
 546                 $links = array();
 547                 if ( $this->mIsBackwards ) {
 548                         $offset = $this->mPastTheEndIndex;
 549                 } else {
 550                         $offset = $this->mOffset;
 551                 }
 552                 foreach ( $this->mLimitsShown as $limit ) {
 553                         $links[] = $this->makeLink(
 554                                 $this->getLanguage()->formatNum( $limit ),
 555                                 array( 'offset' => $offset, 'limit' => $limit ),
 556                                 'num'
 557                         );
 558                 }
 559                 return $links;
 560         }
 561
 562         /**
 563          * Assembles an HTMLForm for the Pager and returns the HTML
 564          *
 565          * @return string
 566          */
 567         public function buildHTMLForm() {
 568                 if ( $this->getHTMLFormFields() === null ) {
 569                         throw new MWException( __METHOD__ . " was called without any form fields being defined" );
 570                 }
 571
 572                 $form = new HTMLForm( $this->getHTMLFormFields(), $this->getContext() );
 573                 $form->setMethod( 'get' );
 574                 $form->setWrapperLegendMsg( $this->getHTMLFormLegend() );
 575                 $form->setSubmitTextMsg( $this->getHTMLFormSubmit() );
 576                 $this->addHiddenFields( $form );
 577                 $this->modifyHTMLForm( $form );
 578                 $form->prepareForm();
 579
 580                 return $form->getHTML( '' );
 581         }
 582
 583         /**
 584          * Adds hidden elements to forms for things that are in the query string.
 585          * This is so that parameters like offset stick through form submissions
 586          *
 587          * @param HTMLForm $form
 588          */
 589         protected function addHiddenFields( HTMLForm $form ) {
 590                 $query = $this->getRequest()->getQueryValues();
 591                 $fieldsBlacklist = array( 'title' );
 592                 $fields = $form->getFlatFields();
 593                 foreach ( $fields as $name => $field ) {
 594                         $fieldsBlacklist[] = $field->getName();
 595                 }
 596                 foreach ( $query as $name => $value ) {
 597                         if ( in_array( $name, $fieldsBlacklist ) ) {
 598                                 continue;
 599                         }
 600                         $form->addHiddenField( $name, $value );
 601                 }
 602         }
 603
 604         /**
 605          * Abstract formatting function. This should return an HTML string
 606          * representing the result row $row. Rows will be concatenated and
 607          * returned by getBody()
 608          *
 609          * @param $row Object: database row
 610          * @return String
 611          */
 612         abstract function formatRow( $row );
 613
 614         /**
 615          * This function should be overridden to provide all parameters
 616          * needed for the main paged query. It returns an associative
 617          * array with the following elements:
 618          *    tables => Table(s) for passing to Database::select()
 619          *    fields => Field(s) for passing to Database::select(), may be *
 620          *    conds => WHERE conditions
 621          *    options => option array
 622          *    join_conds => JOIN conditions
 623          *
 624          * @return Array
 625          */
 626         abstract function getQueryInfo();
 627
 628         /**
 629          * This function should be overridden to return the name of the index fi-
 630          * eld.  If the pager supports multiple orders, it may return an array of
 631          * 'querykey' => 'indexfield' pairs, so that a request with &count=querykey
 632          * will use indexfield to sort.  In this case, the first returned key is
 633          * the default.
 634          *
 635          * Needless to say, it's really not a good idea to use a non-unique index
 636          * for this!  That won't page right.
 637          *
 638          * @return string|Array
 639          */
 640         abstract function getIndexField();
 641
 642         /**
 643          * This function should be overridden to return the names of secondary columns
 644          * to order by in addition to the column in getIndexField(). These fields will
 645          * not be used in the pager offset or in any links for users.
 646          *
 647          * If getIndexField() returns an array of 'querykey' => 'indexfield' pairs then
 648          * this must return a corresponding array of 'querykey' => array( fields...) pairs
 649          * in order for a request with &count=querykey to use array( fields...) to sort.
 650          *
 651          * This is useful for pagers that GROUP BY a unique column (say page_id)
 652          * and ORDER BY another (say page_len). Using GROUP BY and ORDER BY both on
 653          * page_len,page_id avoids temp tables (given a page_len index). This would
 654          * also work if page_id was non-unique but we had a page_len,page_id index.
 655          *
 656          * @return Array
 657          */
 658         protected function getExtraSortFields() { return array(); }
 659
 660         /**
 661          * Return the default sorting direction: false for ascending, true for de-
 662          * scending.  You can also have an associative array of ordertype => dir,
 663          * if multiple order types are supported.  In this case getIndexField()
 664          * must return an array, and the keys of that must exactly match the keys
 665          * of this.
 666          *
 667          * For backward compatibility, this method's return value will be ignored
 668          * if $this->mDefaultDirection is already set when the constructor is
 669          * called, for instance if it's statically initialized.  In that case the
 670          * value of that variable (which must be a boolean) will be used.
 671          *
 672          * Note that despite its name, this does not return the value of the
 673          * $this->mDefaultDirection member variable.  That's the default for this
 674          * particular instantiation, which is a single value.  This is the set of
 675          * all defaults for the class.
 676          *
 677          * @return Boolean
 678          */
 679         protected function getDefaultDirections() { return false; }
 680
 681         /**
 682          * Returns an array for HTMLForm fields for the pager
 683          *
 684          * Only used if the pager makes use of HTMLForms
 685          *
 686          * @return array|null
 687          */
 688         protected function getHTMLFormFields() { return null; }
 689
 690         /**
 691          * Message name for the fieldset legend text
 692          *
 693          * Only used if the pager makes use of HTMLForms
 694          *
 695          * @return string
 696          */
 697         protected function getHTMLFormLegend() { return ''; }
 698
 699         /**
 700          * Message name for the submit button text
 701          *
 702          * Only used if the pager makes use of HTMLForms
 703          *
 704          * @return string
 705          */
 706         protected function getHTMLFormSubmit() { return ''; }
 707
 708         /**
 709          * If the pager needs to do any modifications to the Form, override this
 710          * function.
 711          *
 712          * Only used if the pager makes use of HTMLForms
 713          *
 714          * @param HTMLForm $form
 715          */
 716         protected function modifyHTMLForm( HTMLForm $form ) {}
 717 }
 718
 719
 720 /**
 721  * IndexPager with an alphabetic list and a formatted navigation bar
 722  * @ingroup Pager
 723  */
 724 abstract class AlphabeticPager extends IndexPager {
 725
 726         /**
 727          * Shamelessly stolen bits from ReverseChronologicalPager,
 728          * didn't want to do class magic as may be still revamped
 729          *
 730          * @return String HTML
 731          */
 732         function getNavigationBar() {
 733                 if ( !$this->isNavigationBarShown() ) return '';
 734
 735                 if( isset( $this->mNavigationBar ) ) {
 736                         return $this->mNavigationBar;
 737                 }
 738
 739                 $lang = $this->getLanguage();
 740
 741                 $opts = array( 'parsemag', 'escapenoentities' );
 742                 $linkTexts = array(
 743                         'prev' => wfMsgExt(
 744                                 'prevn',
 745                                 $opts,
 746                                 $lang->formatNum( $this->mLimit )
 747                         ),
 748                         'next' => wfMsgExt(
 749                                 'nextn',
 750                                 $opts,
 751                                 $lang->formatNum($this->mLimit )
 752                         ),
 753                         'first' => wfMsgExt( 'page_first', $opts ),
 754                         'last' => wfMsgExt( 'page_last', $opts )
 755                 );
 756
 757                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 758                 $limitLinks = $this->getLimitLinks();
 759                 $limits = $lang->pipeList( $limitLinks );
 760
 761                 $this->mNavigationBar =
 762                         "(" . $lang->pipeList(
 763                                 array( $pagingLinks['first'],
 764                                 $pagingLinks['last'] )
 765                         ) . ") " .
 766                         wfMsgHtml( 'viewprevnext', $pagingLinks['prev'],
 767                         $pagingLinks['next'], $limits );
 768
 769                 if( !is_array( $this->getIndexField() ) ) {
 770                         # Early return to avoid undue nesting
 771                         return $this->mNavigationBar;
 772                 }
 773
 774                 $extra = '';
 775                 $first = true;
 776                 $msgs = $this->getOrderTypeMessages();
 777                 foreach( array_keys( $msgs ) as $order ) {
 778                         if( $first ) {
 779                                 $first = false;
 780                         } else {
 781                                 $extra .= wfMsgExt( 'pipe-separator' , 'escapenoentities' );
 782                         }
 783
 784                         if( $order == $this->mOrderType ) {
 785                                 $extra .= wfMsgHTML( $msgs[$order] );
 786                         } else {
 787                                 $extra .= $this->makeLink(
 788                                         wfMsgHTML( $msgs[$order] ),
 789                                         array( 'order' => $order )
 790                                 );
 791                         }
 792                 }
 793
 794                 if( $extra !== '' ) {
 795                         $this->mNavigationBar .= " ($extra)";
 796                 }
 797
 798                 return $this->mNavigationBar;
 799         }
 800
 801         /**
 802          * If this supports multiple order type messages, give the message key for
 803          * enabling each one in getNavigationBar.  The return type is an associa-
 804          * tive array whose keys must exactly match the keys of the array returned
 805          * by getIndexField(), and whose values are message keys.
 806          *
 807          * @return Array
 808          */
 809         protected function getOrderTypeMessages() {
 810                 return null;
 811         }
 812 }
 813
 814 /**
 815  * IndexPager with a formatted navigation bar
 816  * @ingroup Pager
 817  */
 818 abstract class ReverseChronologicalPager extends IndexPager {
 819         public $mDefaultDirection = true;
 820         public $mYear;
 821         public $mMonth;
 822
 823         function getNavigationBar() {
 824                 if ( !$this->isNavigationBarShown() ) {
 825                         return '';
 826                 }
 827
 828                 if ( isset( $this->mNavigationBar ) ) {
 829                         return $this->mNavigationBar;
 830                 }
 831
 832                 $nicenumber = $this->getLanguage()->formatNum( $this->mLimit );
 833                 $linkTexts = array(
 834                         'prev' => wfMsgExt(
 835                                 'pager-newer-n',
 836                                 array( 'parsemag', 'escape' ),
 837                                 $nicenumber
 838                         ),
 839                         'next' => wfMsgExt(
 840                                 'pager-older-n',
 841                                 array( 'parsemag', 'escape' ),
 842                                 $nicenumber
 843                         ),
 844                         'first' => wfMsgHtml( 'histlast' ),
 845                         'last' => wfMsgHtml( 'histfirst' )
 846                 );
 847
 848                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 849                 $limitLinks = $this->getLimitLinks();
 850                 $limits = $this->getLanguage()->pipeList( $limitLinks );
 851
 852                 $this->mNavigationBar = "({$pagingLinks['first']}" .
 853                         wfMsgExt( 'pipe-separator' , 'escapenoentities' ) .
 854                         "{$pagingLinks['last']}) " .
 855                         wfMsgHTML(
 856                                 'viewprevnext',
 857                                 $pagingLinks['prev'], $pagingLinks['next'],
 858                                 $limits
 859                         );
 860                 return $this->mNavigationBar;
 861         }
 862
 863         function getDateCond( $year, $month ) {
 864                 $year = intval($year);
 865                 $month = intval($month);
 866                 // Basic validity checks
 867                 $this->mYear = $year > 0 ? $year : false;
 868                 $this->mMonth = ($month > 0 && $month < 13) ? $month : false;
 869                 // Given an optional year and month, we need to generate a timestamp
 870                 // to use as "WHERE rev_timestamp <= result"
 871                 // Examples: year = 2006 equals < 20070101 (+000000)
 872                 // year=2005, month=1    equals < 20050201
 873                 // year=2005, month=12   equals < 20060101
 874                 if ( !$this->mYear && !$this->mMonth ) {
 875                         return;
 876                 }
 877                 if ( $this->mYear ) {
 878                         $year = $this->mYear;
 879                 } else {
 880                         // If no year given, assume the current one
 881                         $year = gmdate( 'Y' );
 882                         // If this month hasn't happened yet this year, go back to last year's month
 883                         if( $this->mMonth > gmdate( 'n' ) ) {
 884                                 $year--;
 885                         }
 886                 }
 887                 if ( $this->mMonth ) {
 888                         $month = $this->mMonth + 1;
 889                         // For December, we want January 1 of the next year
 890                         if ($month > 12) {
 891                                 $month = 1;
 892                                 $year++;
 893                         }
 894                 } else {
 895                         // No month implies we want up to the end of the year in question
 896                         $month = 1;
 897                         $year++;
 898                 }
 899                 // Y2K38 bug
 900                 if ( $year > 2032 ) {
 901                         $year = 2032;
 902                 }
 903                 $ymd = (int)sprintf( "%04d%02d01", $year, $month );
 904                 if ( $ymd > 20320101 ) {
 905                         $ymd = 20320101;
 906                 }
 907                 $this->mOffset = $this->mDb->timestamp( "${ymd}000000" );
 908         }
 909 }
 910
 911 /**
 912  * Table-based display with a user-selectable sort order
 913  * @ingroup Pager
 914  */
 915 abstract class TablePager extends IndexPager {
 916         var $mSort;
 917         var $mCurrentRow;
 918
 919         function __construct( IContextSource $context = null ) {
 920                 if ( $context ) {
 921                         $this->setContext( $context );
 922                 }
 923
 924                 $this->mSort = $this->getRequest()->getText( 'sort' );
 925                 if ( !array_key_exists( $this->mSort, $this->getFieldNames() ) ) {
 926                         $this->mSort = $this->getDefaultSort();
 927                 }
 928                 if ( $this->getRequest()->getBool( 'asc' ) ) {
 929                         $this->mDefaultDirection = false;
 930                 } elseif ( $this->getRequest()->getBool( 'desc' ) ) {
 931                         $this->mDefaultDirection = true;
 932                 } /* Else leave it at whatever the class default is */
 933
 934                 parent::__construct();
 935         }
 936
 937         function getStartBody() {
 938                 global $wgStylePath;
 939                 $tableClass = htmlspecialchars( $this->getTableClass() );
 940                 $sortClass = htmlspecialchars( $this->getSortHeaderClass() );
 941
 942                 $s = "<table style='border:1;' class=\"mw-datatable $tableClass\"><thead><tr>\n";
 943                 $fields = $this->getFieldNames();
 944
 945                 # Make table header
 946                 foreach ( $fields as $field => $name ) {
 947                         if ( strval( $name ) == '' ) {
 948                                 $s .= "<th>&#160;</th>\n";
 949                         } elseif ( $this->isFieldSortable( $field ) ) {
 950                                 $query = array( 'sort' => $field, 'limit' => $this->mLimit );
 951                                 if ( $field == $this->mSort ) {
 952                                         # This is the sorted column
 953                                         # Prepare a link that goes in the other sort order
 954                                         if ( $this->mDefaultDirection ) {
 955                                                 # Descending
 956                                                 $image = 'Arr_d.png';
 957                                                 $query['asc'] = '1';
 958                                                 $query['desc'] = '';
 959                                                 $alt = htmlspecialchars( wfMsg( 'descending_abbrev' ) );
 960                                         } else {
 961                                                 # Ascending
 962                                                 $image = 'Arr_u.png';
 963                                                 $query['asc'] = '';
 964                                                 $query['desc'] = '1';
 965                                                 $alt = htmlspecialchars( wfMsg( 'ascending_abbrev' ) );
 966                                         }
 967                                         $image = htmlspecialchars( "$wgStylePath/common/images/$image" );
 968                                         $link = $this->makeLink(
 969                                                 "<img width=\"12\" height=\"12\" alt=\"$alt\" src=\"$image\" />" .
 970                                                 htmlspecialchars( $name ), $query );
 971                                         $s .= "<th class=\"$sortClass\">$link</th>\n";
 972                                 } else {
 973                                         $s .= '<th>' . $this->makeLink( htmlspecialchars( $name ), $query ) . "</th>\n";
 974                                 }
 975                         } else {
 976                                 $s .= '<th>' . htmlspecialchars( $name ) . "</th>\n";
 977                         }
 978                 }
 979                 $s .= "</tr></thead><tbody>\n";
 980                 return $s;
 981         }
 982
 983         function getEndBody() {
 984                 return "</tbody></table>\n";
 985         }
 986
 987         function getEmptyBody() {
 988                 $colspan = count( $this->getFieldNames() );
 989                 $msgEmpty = wfMsgHtml( 'table_pager_empty' );
 990                 return "<tr><td colspan=\"$colspan\">$msgEmpty</td></tr>\n";
 991         }
 992
 993         /**
 994          * @param $row Array
 995          * @return String HTML
 996          */
 997         function formatRow( $row ) {
 998                 $this->mCurrentRow = $row;      # In case formatValue etc need to know
 999                 $s = Xml::openElement( 'tr', $this->getRowAttrs( $row ) );
1000                 $fieldNames = $this->getFieldNames();
1001                 foreach ( $fieldNames as $field => $name ) {
1002                         $value = isset( $row->$field ) ? $row->$field : null;
1003                         $formatted = strval( $this->formatValue( $field, $value ) );
1004                         if ( $formatted == '' ) {
1005                                 $formatted = '&#160;';
1006                         }
1007                         $s .= Xml::tags( 'td', $this->getCellAttrs( $field, $value ), $formatted );
1008                 }
1009                 $s .= "</tr>\n";
1010                 return $s;
1011         }
1012
1013         /**
1014          * Get a class name to be applied to the given row.
1015          *
1016          * @param $row Object: the database result row
1017          * @return String
1018          */
1019         function getRowClass( $row ) {
1020                 return '';
1021         }
1022
1023         /**
1024          * Get attributes to be applied to the given row.
1025          *
1026          * @param $row Object: the database result row
1027          * @return Array of <attr> => <value>
1028          */
1029         function getRowAttrs( $row ) {
1030                 $class = $this->getRowClass( $row );
1031                 if ( $class === '' ) {
1032                         // Return an empty array to avoid clutter in HTML like class=""
1033                         return array();
1034                 } else {
1035                         return array( 'class' => $this->getRowClass( $row ) );
1036                 }
1037         }
1038
1039         /**
1040          * Get any extra attributes to be applied to the given cell. Don't
1041          * take this as an excuse to hardcode styles; use classes and
1042          * CSS instead.  Row context is available in $this->mCurrentRow
1043          *
1044          * @param $field String The column
1045          * @param $value String The cell contents
1046          * @return Array of attr => value
1047          */
1048         function getCellAttrs( $field, $value ) {
1049                 return array( 'class' => 'TablePager_col_' . $field );
1050         }
1051
1052         function getIndexField() {
1053                 return $this->mSort;
1054         }
1055
1056         function getTableClass() {
1057                 return 'TablePager';
1058         }
1059
1060         function getNavClass() {
1061                 return 'TablePager_nav';
1062         }
1063
1064         function getSortHeaderClass() {
1065                 return 'TablePager_sort';
1066         }
1067
1068         /**
1069          * A navigation bar with images
1070          * @return String HTML
1071          */
1072         function getNavigationBar() {
1073                 global $wgStylePath;
1074
1075                 if ( !$this->isNavigationBarShown() ) {
1076                         return '';
1077                 }
1078
1079                 $path = "$wgStylePath/common/images";
1080                 $labels = array(
1081                         'first' => 'table_pager_first',
1082                         'prev' => 'table_pager_prev',
1083                         'next' => 'table_pager_next',
1084                         'last' => 'table_pager_last',
1085                 );
1086                 $images = array(
1087                         'first' => 'arrow_first_25.png',
1088                         'prev' => 'arrow_left_25.png',
1089                         'next' => 'arrow_right_25.png',
1090                         'last' => 'arrow_last_25.png',
1091                 );
1092                 $disabledImages = array(
1093                         'first' => 'arrow_disabled_first_25.png',
1094                         'prev' => 'arrow_disabled_left_25.png',
1095                         'next' => 'arrow_disabled_right_25.png',
1096                         'last' => 'arrow_disabled_last_25.png',
1097                 );
1098                 if( $this->getLanguage()->isRTL() ) {
1099                         $keys = array_keys( $labels );
1100                         $images = array_combine( $keys, array_reverse( $images ) );
1101                         $disabledImages = array_combine( $keys, array_reverse( $disabledImages ) );
1102                 }
1103
1104                 $linkTexts = array();
1105                 $disabledTexts = array();
1106                 foreach ( $labels as $type => $label ) {
1107                         $msgLabel = wfMsgHtml( $label );
1108                         $linkTexts[$type] = "<img src=\"$path/{$images[$type]}\" alt=\"$msgLabel\"/><br />$msgLabel";
1109                         $disabledTexts[$type] = "<img src=\"$path/{$disabledImages[$type]}\" alt=\"$msgLabel\"/><br />$msgLabel";
1110                 }
1111                 $links = $this->getPagingLinks( $linkTexts, $disabledTexts );
1112
1113                 $navClass = htmlspecialchars( $this->getNavClass() );
1114                 $s = "<table class=\"$navClass\"><tr>\n";
1115                 $width = 100 / count( $links ) . '%';
1116                 foreach ( $labels as $type => $label ) {
1117                         $s .= "<td style='width:$width;'>{$links[$type]}</td>\n";
1118                 }
1119                 $s .= "</tr></table>\n";
1120                 return $s;
1121         }
1122
1123         /**
1124          * Get a <select> element which has options for each of the allowed limits
1125          *
1126          * @return String: HTML fragment
1127          */
1128         function getLimitSelect() {
1129                 # Add the current limit from the query string
1130                 # to avoid that the limit is lost after clicking Go next time
1131                 if ( !in_array( $this->mLimit, $this->mLimitsShown ) ) {
1132                         $this->mLimitsShown[] = $this->mLimit;
1133                         sort( $this->mLimitsShown );
1134                 }
1135                 $s = Html::openElement( 'select', array( 'name' => 'limit' ) ) . "\n";
1136                 foreach ( $this->mLimitsShown as $key => $value ) {
1137                         # The pair is either $index => $limit, in which case the $value
1138                         # will be numeric, or $limit => $text, in which case the $value
1139                         # will be a string.
1140                         if( is_int( $value ) ){
1141                                 $limit = $value;
1142                                 $text = $this->getLanguage()->formatNum( $limit );
1143                         } else {
1144                                 $limit = $key;
1145                                 $text = $value;
1146                         }
1147                         $s .= Xml::option( $text, $limit, $limit == $this->mLimit ) . "\n";
1148                 }
1149                 $s .= Html::closeElement( 'select' );
1150                 return $s;
1151         }
1152
1153         /**
1154          * Returns an HTMLFormField definition for the "Items per page:" dropdown
1155          *
1156          * @return array
1157          */
1158         protected function getHTMLFormLimitSelect() {
1159                 $f = array(
1160                         'class' => 'HTMLItemsPerPageField',
1161                         'label-message' => 'table_pager_limit_label',
1162                         'options' => array(),
1163                         'default' => $this->mDefaultLimit,
1164                         'name' => 'limit',
1165                 );
1166
1167                 foreach( $this->mLimitsShown as $limit ) {
1168                         $f['options'][$this->getLanguage()->formatNum( $limit )] = $limit;
1169                 }
1170
1171                 return $f;
1172         }
1173
1174         /**
1175          * Get <input type="hidden"> elements for use in a method="get" form.
1176          * Resubmits all defined elements of the query string, except for a
1177          * blacklist, passed in the $blacklist parameter.
1178          *
1179          * @param $blacklist Array parameters from the request query which should not be resubmitted
1180          * @return String: HTML fragment
1181          */
1182         function getHiddenFields( $blacklist = array() ) {
1183                 $blacklist = (array)$blacklist;
1184                 $query = $this->getRequest()->getQueryValues();
1185                 foreach ( $blacklist as $name ) {
1186                         unset( $query[$name] );
1187                 }
1188                 $s = '';
1189                 foreach ( $query as $name => $value ) {
1190                         $encName = htmlspecialchars( $name );
1191                         $encValue = htmlspecialchars( $value );
1192                         $s .= "<input type=\"hidden\" name=\"$encName\" value=\"$encValue\"/>\n";
1193                 }
1194                 return $s;
1195         }
1196
1197         /**
1198          * Get a form containing a limit selection dropdown
1199          *
1200          * @return String: HTML fragment
1201          */
1202         function getLimitForm() {
1203                 global $wgScript;
1204
1205                 return Xml::openElement(
1206                         'form',
1207                         array(
1208                                 'method' => 'get',
1209                                 'action' => $wgScript
1210                         ) ) . "\n" . $this->getLimitDropdown() . "</form>\n";
1211         }
1212
1213         /**
1214          * Gets a limit selection dropdown
1215          *
1216          * @return string
1217          */
1218         function getLimitDropdown() {
1219                 # Make the select with some explanatory text
1220                 $msgSubmit = wfMsgHtml( 'table_pager_limit_submit' );
1221
1222                 return wfMsgHtml( 'table_pager_limit', $this->getLimitSelect() ) .
1223                         "\n<input type=\"submit\" value=\"$msgSubmit\"/>\n" .
1224                         $this->getHiddenFields( array( 'limit' ) );
1225         }
1226
1227         /**
1228          * Return true if the named field should be sortable by the UI, false
1229          * otherwise
1230          *
1231          * @param $field String
1232          */
1233         abstract function isFieldSortable( $field );
1234
1235         /**
1236          * Format a table cell. The return value should be HTML, but use an empty
1237          * string not &#160; for empty cells. Do not include the <td> and </td>.
1238          *
1239          * The current result row is available as $this->mCurrentRow, in case you
1240          * need more context.
1241          *
1242          * @param $name String: the database field name
1243          * @param $value String: the value retrieved from the database
1244          */
1245         abstract function formatValue( $name, $value );
1246
1247         /**
1248          * The database field name used as a default sort order
1249          */
1250         abstract function getDefaultSort();
1251
1252         /**
1253          * An array mapping database field names to a textual description of the
1254          * field name, for use in the table header. The description should be plain
1255          * text, it will be HTML-escaped later.
1256          *
1257          * @return Array
1258          */
1259         abstract function getFieldNames();
1260 }
1261
1262 /**
1263  * Items per page dropdown for HTMLForm
1264  */
1265 class HTMLItemsPerPageField extends HTMLSelectField {
1266         /**
1267          * Basically don't do any validation. If it's a number that's fine. Also,
1268          * add it to the list if it's not there already
1269          *
1270          * @param $value
1271          * @param $alldata
1272          * @return bool
1273          */
1274         function validate( $value, $alldata ) {
1275                 if ( $value == '' ) {
1276                         return true;
1277                 }
1278
1279                 if ( !in_array( $value, $this->mParams['options'] ) ) {
1280                         $this->mParams['options'][ $this->mParent->getLanguage()->formatNum( $value ) ] = intval($value);
1281                         asort( $this->mParams['options'] );
1282                 }
1283
1284                 return true;
1285         }
1286
1287 }