includes/Pager.php

   1 <?php
   2 /**
   3  * Efficient paging for SQL queries.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Pager
  22  */
  23
  24 /**
  25  * @defgroup Pager Pager
  26  */
  27
  28 /**
  29  * Basic pager interface.
  30  * @ingroup Pager
  31  */
  32 interface Pager {
  33         function getNavigationBar();
  34         function getBody();
  35 }
  36
  37 /**
  38  * IndexPager is an efficient pager which uses a (roughly unique) index in the
  39  * data set to implement paging, rather than a "LIMIT offset,limit" clause.
  40  * In MySQL, such a limit/offset clause requires counting through the
  41  * specified number of offset rows to find the desired data, which can be
  42  * expensive for large offsets.
  43  *
  44  * ReverseChronologicalPager is a child class of the abstract IndexPager, and
  45  * contains  some formatting and display code which is specific to the use of
  46  * timestamps as  indexes. Here is a synopsis of its operation:
  47  *
  48  *    * The query is specified by the offset, limit and direction (dir)
  49  *      parameters, in addition to any subclass-specific parameters.
  50  *    * The offset is the non-inclusive start of the DB query. A row with an
  51  *      index value equal to the offset will never be shown.
  52  *    * The query may either be done backwards, where the rows are returned by
  53  *      the database in the opposite order to which they are displayed to the
  54  *      user, or forwards. This is specified by the "dir" parameter, dir=prev
  55  *      means backwards, anything else means forwards. The offset value
  56  *      specifies the start of the database result set, which may be either
  57  *      the start or end of the displayed data set. This allows "previous"
  58  *      links to be implemented without knowledge of the index value at the
  59  *      start of the previous page.
  60  *    * An additional row beyond the user-specified limit is always requested.
  61  *      This allows us to tell whether we should display a "next" link in the
  62  *      case of forwards mode, or a "previous" link in the case of backwards
  63  *      mode. Determining whether to display the other link (the one for the
  64  *      page before the start of the database result set) can be done
  65  *      heuristically by examining the offset.
  66  *
  67  *    * An empty offset indicates that the offset condition should be omitted
  68  *      from the query. This naturally produces either the first page or the
  69  *      last page depending on the dir parameter.
  70  *
  71  *  Subclassing the pager to implement concrete functionality should be fairly
  72  *  simple, please see the examples in HistoryPage.php and
  73  *  SpecialBlockList.php. You just need to override formatRow(),
  74  *  getQueryInfo() and getIndexField(). Don't forget to call the parent
  75  *  constructor if you override it.
  76  *
  77  * @ingroup Pager
  78  */
  79 abstract class IndexPager extends ContextSource implements Pager {
  80         public $mRequest;
  81         public $mLimitsShown = array( 20, 50, 100, 250, 500 );
  82         public $mDefaultLimit = 50;
  83         public $mOffset, $mLimit;
  84         public $mQueryDone = false;
  85         public $mDb;
  86         public $mPastTheEndRow;
  87
  88         /**
  89          * The index to actually be used for ordering. This is a single column,
  90          * for one ordering, even if multiple orderings are supported.
  91          */
  92         protected $mIndexField;
  93         /**
  94          * An array of secondary columns to order by. These fields are not part of the offset.
  95          * This is a column list for one ordering, even if multiple orderings are supported.
  96          */
  97         protected $mExtraSortFields;
  98         /** For pages that support multiple types of ordering, which one to use.
  99          */
 100         protected $mOrderType;
 101         /**
 102          * $mDefaultDirection gives the direction to use when sorting results:
 103          * false for ascending, true for descending.  If $mIsBackwards is set, we
 104          * start from the opposite end, but we still sort the page itself according
 105          * to $mDefaultDirection.  E.g., if $mDefaultDirection is false but we're
 106          * going backwards, we'll display the last page of results, but the last
 107          * result will be at the bottom, not the top.
 108          *
 109          * Like $mIndexField, $mDefaultDirection will be a single value even if the
 110          * class supports multiple default directions for different order types.
 111          */
 112         public $mDefaultDirection;
 113         public $mIsBackwards;
 114
 115         /** True if the current result set is the first one */
 116         public $mIsFirst;
 117         public $mIsLast;
 118
 119         protected $mLastShown, $mFirstShown, $mPastTheEndIndex, $mDefaultQuery, $mNavigationBar;
 120
 121         /**
 122          * Result object for the query. Warning: seek before use.
 123          *
 124          * @var ResultWrapper
 125          */
 126         public $mResult;
 127
 128         public function __construct( IContextSource $context = null ) {
 129                 if ( $context ) {
 130                         $this->setContext( $context );
 131                 }
 132
 133                 $this->mRequest = $this->getRequest();
 134
 135                 # NB: the offset is quoted, not validated. It is treated as an
 136                 # arbitrary string to support the widest variety of index types. Be
 137                 # careful outputting it into HTML!
 138                 $this->mOffset = $this->mRequest->getText( 'offset' );
 139
 140                 # Use consistent behavior for the limit options
 141                 $this->mDefaultLimit = intval( $this->getUser()->getOption( 'rclimit' ) );
 142                 list( $this->mLimit, /* $offset */ ) = $this->mRequest->getLimitOffset();
 143
 144                 $this->mIsBackwards = ( $this->mRequest->getVal( 'dir' ) == 'prev' );
 145                 $this->mDb = wfGetDB( DB_SLAVE );
 146
 147                 $index = $this->getIndexField(); // column to sort on
 148                 $extraSort = $this->getExtraSortFields(); // extra columns to sort on for query planning
 149                 $order = $this->mRequest->getVal( 'order' );
 150                 if( is_array( $index ) && isset( $index[$order] ) ) {
 151                         $this->mOrderType = $order;
 152                         $this->mIndexField = $index[$order];
 153                         $this->mExtraSortFields = isset( $extraSort[$order] )
 154                                 ? (array)$extraSort[$order]
 155                                 : array();
 156                 } elseif( is_array( $index ) ) {
 157                         # First element is the default
 158                         reset( $index );
 159                         list( $this->mOrderType, $this->mIndexField ) = each( $index );
 160                         $this->mExtraSortFields = isset( $extraSort[$this->mOrderType] )
 161                                 ? (array)$extraSort[$this->mOrderType]
 162                                 : array();
 163                 } else {
 164                         # $index is not an array
 165                         $this->mOrderType = null;
 166                         $this->mIndexField = $index;
 167                         $this->mExtraSortFields = (array)$extraSort;
 168                 }
 169
 170                 if( !isset( $this->mDefaultDirection ) ) {
 171                         $dir = $this->getDefaultDirections();
 172                         $this->mDefaultDirection = is_array( $dir )
 173                                 ? $dir[$this->mOrderType]
 174                                 : $dir;
 175                 }
 176         }
 177
 178         /**
 179          * Get the Database object in use
 180          *
 181          * @return DatabaseBase
 182          */
 183         public function getDatabase() {
 184                 return $this->mDb;
 185         }
 186
 187         /**
 188          * Do the query, using information from the object context. This function
 189          * has been kept minimal to make it overridable if necessary, to allow for
 190          * result sets formed from multiple DB queries.
 191          */
 192         public function doQuery() {
 193                 # Use the child class name for profiling
 194                 $fname = __METHOD__ . ' (' . get_class( $this ) . ')';
 195                 wfProfileIn( $fname );
 196
 197                 $descending = ( $this->mIsBackwards == $this->mDefaultDirection );
 198                 # Plus an extra row so that we can tell the "next" link should be shown
 199                 $queryLimit = $this->mLimit + 1;
 200
 201                 $this->mResult = $this->reallyDoQuery(
 202                         $this->mOffset,
 203                         $queryLimit,
 204                         $descending
 205                 );
 206
 207                 $this->extractResultInfo( $this->mOffset, $queryLimit, $this->mResult );
 208                 $this->mQueryDone = true;
 209
 210                 $this->preprocessResults( $this->mResult );
 211                 $this->mResult->rewind(); // Paranoia
 212
 213                 wfProfileOut( $fname );
 214         }
 215
 216         /**
 217          * @return ResultWrapper The result wrapper.
 218          */
 219         function getResult() {
 220                 return $this->mResult;
 221         }
 222
 223         /**
 224          * Set the offset from an other source than the request
 225          *
 226          * @param $offset Int|String
 227          */
 228         function setOffset( $offset ) {
 229                 $this->mOffset = $offset;
 230         }
 231         /**
 232          * Set the limit from an other source than the request
 233          *
 234          * @param $limit Int|String
 235          */
 236         function setLimit( $limit ) {
 237                 $this->mLimit = $limit;
 238         }
 239
 240         /**
 241          * Extract some useful data from the result object for use by
 242          * the navigation bar, put it into $this
 243          *
 244          * @param $offset String: index offset, inclusive
 245          * @param $limit Integer: exact query limit
 246          * @param $res ResultWrapper
 247          */
 248         function extractResultInfo( $offset, $limit, ResultWrapper $res ) {
 249                 $numRows = $res->numRows();
 250                 if ( $numRows ) {
 251                         # Remove any table prefix from index field
 252                         $parts = explode( '.', $this->mIndexField );
 253                         $indexColumn = end( $parts );
 254
 255                         $row = $res->fetchRow();
 256                         $firstIndex = $row[$indexColumn];
 257
 258                         # Discard the extra result row if there is one
 259                         if ( $numRows > $this->mLimit && $numRows > 1 ) {
 260                                 $res->seek( $numRows - 1 );
 261                                 $this->mPastTheEndRow = $res->fetchObject();
 262                                 $indexField = $this->mIndexField;
 263                                 $this->mPastTheEndIndex = $this->mPastTheEndRow->$indexField;
 264                                 $res->seek( $numRows - 2 );
 265                                 $row = $res->fetchRow();
 266                                 $lastIndex = $row[$indexColumn];
 267                         } else {
 268                                 $this->mPastTheEndRow = null;
 269                                 # Setting indexes to an empty string means that they will be
 270                                 # omitted if they would otherwise appear in URLs. It just so
 271                                 # happens that this  is the right thing to do in the standard
 272                                 # UI, in all the relevant cases.
 273                                 $this->mPastTheEndIndex = '';
 274                                 $res->seek( $numRows - 1 );
 275                                 $row = $res->fetchRow();
 276                                 $lastIndex = $row[$indexColumn];
 277                         }
 278                 } else {
 279                         $firstIndex = '';
 280                         $lastIndex = '';
 281                         $this->mPastTheEndRow = null;
 282                         $this->mPastTheEndIndex = '';
 283                 }
 284
 285                 if ( $this->mIsBackwards ) {
 286                         $this->mIsFirst = ( $numRows < $limit );
 287                         $this->mIsLast = ( $offset == '' );
 288                         $this->mLastShown = $firstIndex;
 289                         $this->mFirstShown = $lastIndex;
 290                 } else {
 291                         $this->mIsFirst = ( $offset == '' );
 292                         $this->mIsLast = ( $numRows < $limit );
 293                         $this->mLastShown = $lastIndex;
 294                         $this->mFirstShown = $firstIndex;
 295                 }
 296         }
 297
 298         /**
 299          * Get some text to go in brackets in the "function name" part of the SQL comment
 300          *
 301          * @return String
 302          */
 303         function getSqlComment() {
 304                 return get_class( $this );
 305         }
 306
 307         /**
 308          * Do a query with specified parameters, rather than using the object
 309          * context
 310          *
 311          * @param $offset String: index offset, inclusive
 312          * @param $limit Integer: exact query limit
 313          * @param $descending Boolean: query direction, false for ascending, true for descending
 314          * @return ResultWrapper
 315          */
 316         public function reallyDoQuery( $offset, $limit, $descending ) {
 317                 list( $tables, $fields, $conds, $fname, $options, $join_conds ) = $this->buildQueryInfo( $offset, $limit, $descending );
 318                 return $this->mDb->select( $tables, $fields, $conds, $fname, $options, $join_conds );
 319         }
 320
 321         /**
 322          * Build variables to use by the database wrapper.
 323          *
 324          * @param $offset String: index offset, inclusive
 325          * @param $limit Integer: exact query limit
 326          * @param $descending Boolean: query direction, false for ascending, true for descending
 327          * @return array
 328          */
 329         protected function buildQueryInfo( $offset, $limit, $descending ) {
 330                 $fname = __METHOD__ . ' (' . $this->getSqlComment() . ')';
 331                 $info = $this->getQueryInfo();
 332                 $tables = $info['tables'];
 333                 $fields = $info['fields'];
 334                 $conds = isset( $info['conds'] ) ? $info['conds'] : array();
 335                 $options = isset( $info['options'] ) ? $info['options'] : array();
 336                 $join_conds = isset( $info['join_conds'] ) ? $info['join_conds'] : array();
 337                 $sortColumns = array_merge( array( $this->mIndexField ), $this->mExtraSortFields );
 338                 if ( $descending ) {
 339                         $options['ORDER BY'] = $sortColumns;
 340                         $operator = '>';
 341                 } else {
 342                         $orderBy = array();
 343                         foreach ( $sortColumns as $col ) {
 344                                 $orderBy[] = $col . ' DESC';
 345                         }
 346                         $options['ORDER BY'] = $orderBy;
 347                         $operator = '<';
 348                 }
 349                 if ( $offset != '' ) {
 350                         $conds[] = $this->mIndexField . $operator . $this->mDb->addQuotes( $offset );
 351                 }
 352                 $options['LIMIT'] = intval( $limit );
 353                 return array( $tables, $fields, $conds, $fname, $options, $join_conds );
 354         }
 355
 356         /**
 357          * Pre-process results; useful for performing batch existence checks, etc.
 358          *
 359          * @param $result ResultWrapper
 360          */
 361         protected function preprocessResults( $result ) {}
 362
 363         /**
 364          * Get the formatted result list. Calls getStartBody(), formatRow() and
 365          * getEndBody(), concatenates the results and returns them.
 366          *
 367          * @return String
 368          */
 369         public function getBody() {
 370                 if ( !$this->mQueryDone ) {
 371                         $this->doQuery();
 372                 }
 373
 374                 if ( $this->mResult->numRows() ) {
 375                         # Do any special query batches before display
 376                         $this->doBatchLookups();
 377                 }
 378
 379                 # Don't use any extra rows returned by the query
 380                 $numRows = min( $this->mResult->numRows(), $this->mLimit );
 381
 382                 $s = $this->getStartBody();
 383                 if ( $numRows ) {
 384                         if ( $this->mIsBackwards ) {
 385                                 for ( $i = $numRows - 1; $i >= 0; $i-- ) {
 386                                         $this->mResult->seek( $i );
 387                                         $row = $this->mResult->fetchObject();
 388                                         $s .= $this->formatRow( $row );
 389                                 }
 390                         } else {
 391                                 $this->mResult->seek( 0 );
 392                                 for ( $i = 0; $i < $numRows; $i++ ) {
 393                                         $row = $this->mResult->fetchObject();
 394                                         $s .= $this->formatRow( $row );
 395                                 }
 396                         }
 397                 } else {
 398                         $s .= $this->getEmptyBody();
 399                 }
 400                 $s .= $this->getEndBody();
 401                 return $s;
 402         }
 403
 404         /**
 405          * Make a self-link
 406          *
 407          * @param $text String: text displayed on the link
 408          * @param $query Array: associative array of paramter to be in the query string
 409          * @param $type String: value of the "rel" attribute
 410          *
 411          * @return String: HTML fragment
 412          */
 413         function makeLink( $text, array $query = null, $type = null ) {
 414                 if ( $query === null ) {
 415                         return $text;
 416                 }
 417
 418                 $attrs = array();
 419                 if( in_array( $type, array( 'first', 'prev', 'next', 'last' ) ) ) {
 420                         # HTML5 rel attributes
 421                         $attrs['rel'] = $type;
 422                 }
 423
 424                 if( $type ) {
 425                         $attrs['class'] = "mw-{$type}link";
 426                 }
 427
 428                 return Linker::linkKnown(
 429                         $this->getTitle(),
 430                         $text,
 431                         $attrs,
 432                         $query + $this->getDefaultQuery()
 433                 );
 434         }
 435
 436         /**
 437          * Called from getBody(), before getStartBody() is called and
 438          * after doQuery() was called. This will be called only if there
 439          * are rows in the result set.
 440          *
 441          * @return void
 442          */
 443         protected function doBatchLookups() {}
 444
 445         /**
 446          * Hook into getBody(), allows text to be inserted at the start. This
 447          * will be called even if there are no rows in the result set.
 448          *
 449          * @return String
 450          */
 451         protected function getStartBody() {
 452                 return '';
 453         }
 454
 455         /**
 456          * Hook into getBody() for the end of the list
 457          *
 458          * @return String
 459          */
 460         protected function getEndBody() {
 461                 return '';
 462         }
 463
 464         /**
 465          * Hook into getBody(), for the bit between the start and the
 466          * end when there are no rows
 467          *
 468          * @return String
 469          */
 470         protected function getEmptyBody() {
 471                 return '';
 472         }
 473
 474         /**
 475          * Get an array of query parameters that should be put into self-links.
 476          * By default, all parameters passed in the URL are used, except for a
 477          * short blacklist.
 478          *
 479          * @return array Associative array
 480          */
 481         function getDefaultQuery() {
 482                 if ( !isset( $this->mDefaultQuery ) ) {
 483                         $this->mDefaultQuery = $this->getRequest()->getQueryValues();
 484                         unset( $this->mDefaultQuery['title'] );
 485                         unset( $this->mDefaultQuery['dir'] );
 486                         unset( $this->mDefaultQuery['offset'] );
 487                         unset( $this->mDefaultQuery['limit'] );
 488                         unset( $this->mDefaultQuery['order'] );
 489                         unset( $this->mDefaultQuery['month'] );
 490                         unset( $this->mDefaultQuery['year'] );
 491                 }
 492                 return $this->mDefaultQuery;
 493         }
 494
 495         /**
 496          * Get the number of rows in the result set
 497          *
 498          * @return Integer
 499          */
 500         function getNumRows() {
 501                 if ( !$this->mQueryDone ) {
 502                         $this->doQuery();
 503                 }
 504                 return $this->mResult->numRows();
 505         }
 506
 507         /**
 508          * Get a URL query array for the prev, next, first and last links.
 509          *
 510          * @return Array
 511          */
 512         function getPagingQueries() {
 513                 if ( !$this->mQueryDone ) {
 514                         $this->doQuery();
 515                 }
 516
 517                 # Don't announce the limit everywhere if it's the default
 518                 $urlLimit = $this->mLimit == $this->mDefaultLimit ? null : $this->mLimit;
 519
 520                 if ( $this->mIsFirst ) {
 521                         $prev = false;
 522                         $first = false;
 523                 } else {
 524                         $prev = array(
 525                                 'dir' => 'prev',
 526                                 'offset' => $this->mFirstShown,
 527                                 'limit' => $urlLimit
 528                         );
 529                         $first = array( 'limit' => $urlLimit );
 530                 }
 531                 if ( $this->mIsLast ) {
 532                         $next = false;
 533                         $last = false;
 534                 } else {
 535                         $next = array( 'offset' => $this->mLastShown, 'limit' => $urlLimit );
 536                         $last = array( 'dir' => 'prev', 'limit' => $urlLimit );
 537                 }
 538                 return array(
 539                         'prev' => $prev,
 540                         'next' => $next,
 541                         'first' => $first,
 542                         'last' => $last
 543                 );
 544         }
 545
 546         /**
 547          * Returns whether to show the "navigation bar"
 548          *
 549          * @return Boolean
 550          */
 551         function isNavigationBarShown() {
 552                 if ( !$this->mQueryDone ) {
 553                         $this->doQuery();
 554                 }
 555                 // Hide navigation by default if there is nothing to page
 556                 return !($this->mIsFirst && $this->mIsLast);
 557         }
 558
 559         /**
 560          * Get paging links. If a link is disabled, the item from $disabledTexts
 561          * will be used. If there is no such item, the unlinked text from
 562          * $linkTexts will be used. Both $linkTexts and $disabledTexts are arrays
 563          * of HTML.
 564          *
 565          * @param $linkTexts Array
 566          * @param $disabledTexts Array
 567          * @return Array
 568          */
 569         function getPagingLinks( $linkTexts, $disabledTexts = array() ) {
 570                 $queries = $this->getPagingQueries();
 571                 $links = array();
 572
 573                 foreach ( $queries as $type => $query ) {
 574                         if ( $query !== false ) {
 575                                 $links[$type] = $this->makeLink(
 576                                         $linkTexts[$type],
 577                                         $queries[$type],
 578                                         $type
 579                                 );
 580                         } elseif ( isset( $disabledTexts[$type] ) ) {
 581                                 $links[$type] = $disabledTexts[$type];
 582                         } else {
 583                                 $links[$type] = $linkTexts[$type];
 584                         }
 585                 }
 586
 587                 return $links;
 588         }
 589
 590         function getLimitLinks() {
 591                 $links = array();
 592                 if ( $this->mIsBackwards ) {
 593                         $offset = $this->mPastTheEndIndex;
 594                 } else {
 595                         $offset = $this->mOffset;
 596                 }
 597                 foreach ( $this->mLimitsShown as $limit ) {
 598                         $links[] = $this->makeLink(
 599                                 $this->getLanguage()->formatNum( $limit ),
 600                                 array( 'offset' => $offset, 'limit' => $limit ),
 601                                 'num'
 602                         );
 603                 }
 604                 return $links;
 605         }
 606
 607         /**
 608          * Abstract formatting function. This should return an HTML string
 609          * representing the result row $row. Rows will be concatenated and
 610          * returned by getBody()
 611          *
 612          * @param $row Object: database row
 613          * @return String
 614          */
 615         abstract function formatRow( $row );
 616
 617         /**
 618          * This function should be overridden to provide all parameters
 619          * needed for the main paged query. It returns an associative
 620          * array with the following elements:
 621          *    tables => Table(s) for passing to Database::select()
 622          *    fields => Field(s) for passing to Database::select(), may be *
 623          *    conds => WHERE conditions
 624          *    options => option array
 625          *    join_conds => JOIN conditions
 626          *
 627          * @return Array
 628          */
 629         abstract function getQueryInfo();
 630
 631         /**
 632          * This function should be overridden to return the name of the index fi-
 633          * eld.  If the pager supports multiple orders, it may return an array of
 634          * 'querykey' => 'indexfield' pairs, so that a request with &count=querykey
 635          * will use indexfield to sort.  In this case, the first returned key is
 636          * the default.
 637          *
 638          * Needless to say, it's really not a good idea to use a non-unique index
 639          * for this!  That won't page right.
 640          *
 641          * @return string|Array
 642          */
 643         abstract function getIndexField();
 644
 645         /**
 646          * This function should be overridden to return the names of secondary columns
 647          * to order by in addition to the column in getIndexField(). These fields will
 648          * not be used in the pager offset or in any links for users.
 649          *
 650          * If getIndexField() returns an array of 'querykey' => 'indexfield' pairs then
 651          * this must return a corresponding array of 'querykey' => array( fields...) pairs
 652          * in order for a request with &count=querykey to use array( fields...) to sort.
 653          *
 654          * This is useful for pagers that GROUP BY a unique column (say page_id)
 655          * and ORDER BY another (say page_len). Using GROUP BY and ORDER BY both on
 656          * page_len,page_id avoids temp tables (given a page_len index). This would
 657          * also work if page_id was non-unique but we had a page_len,page_id index.
 658          *
 659          * @return Array
 660          */
 661         protected function getExtraSortFields() { return array(); }
 662
 663         /**
 664          * Return the default sorting direction: false for ascending, true for de-
 665          * scending.  You can also have an associative array of ordertype => dir,
 666          * if multiple order types are supported.  In this case getIndexField()
 667          * must return an array, and the keys of that must exactly match the keys
 668          * of this.
 669          *
 670          * For backward compatibility, this method's return value will be ignored
 671          * if $this->mDefaultDirection is already set when the constructor is
 672          * called, for instance if it's statically initialized.  In that case the
 673          * value of that variable (which must be a boolean) will be used.
 674          *
 675          * Note that despite its name, this does not return the value of the
 676          * $this->mDefaultDirection member variable.  That's the default for this
 677          * particular instantiation, which is a single value.  This is the set of
 678          * all defaults for the class.
 679          *
 680          * @return Boolean
 681          */
 682         protected function getDefaultDirections() { return false; }
 683 }
 684
 685
 686 /**
 687  * IndexPager with an alphabetic list and a formatted navigation bar
 688  * @ingroup Pager
 689  */
 690 abstract class AlphabeticPager extends IndexPager {
 691
 692         /**
 693          * Shamelessly stolen bits from ReverseChronologicalPager,
 694          * didn't want to do class magic as may be still revamped
 695          *
 696          * @return String HTML
 697          */
 698         function getNavigationBar() {
 699                 if ( !$this->isNavigationBarShown() ) {
 700                         return '';
 701                 }
 702
 703                 if( isset( $this->mNavigationBar ) ) {
 704                         return $this->mNavigationBar;
 705                 }
 706
 707                 $linkTexts = array(
 708                         'prev' => $this->msg( 'prevn' )->numParams( $this->mLimit )->escaped(),
 709                         'next' => $this->msg( 'nextn' )->numParams( $this->mLimit )->escaped(),
 710                         'first' => $this->msg( 'page_first' )->escaped(),
 711                         'last' => $this->msg( 'page_last' )->escaped()
 712                 );
 713
 714                 $lang = $this->getLanguage();
 715
 716                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 717                 $limitLinks = $this->getLimitLinks();
 718                 $limits = $lang->pipeList( $limitLinks );
 719
 720                 $this->mNavigationBar = $this->msg( 'parentheses' )->rawParams(
 721                         $lang->pipeList( array( $pagingLinks['first'],
 722                         $pagingLinks['last'] ) ) )->escaped() . " " .
 723                         $this->msg( 'viewprevnext' )->rawParams( $pagingLinks['prev'],
 724                                 $pagingLinks['next'], $limits )->escaped();
 725
 726                 if( !is_array( $this->getIndexField() ) ) {
 727                         # Early return to avoid undue nesting
 728                         return $this->mNavigationBar;
 729                 }
 730
 731                 $extra = '';
 732                 $first = true;
 733                 $msgs = $this->getOrderTypeMessages();
 734                 foreach( array_keys( $msgs ) as $order ) {
 735                         if( $first ) {
 736                                 $first = false;
 737                         } else {
 738                                 $extra .= $this->msg( 'pipe-separator' )->escaped();
 739                         }
 740
 741                         if( $order == $this->mOrderType ) {
 742                                 $extra .= $this->msg( $msgs[$order] )->escaped();
 743                         } else {
 744                                 $extra .= $this->makeLink(
 745                                         $this->msg( $msgs[$order] )->escaped(),
 746                                         array( 'order' => $order )
 747                                 );
 748                         }
 749                 }
 750
 751                 if( $extra !== '' ) {
 752                         $extra = ' ' . $this->msg( 'parentheses' )->rawParams( $extra )->escaped();
 753                         $this->mNavigationBar .= $extra;
 754                 }
 755
 756                 return $this->mNavigationBar;
 757         }
 758
 759         /**
 760          * If this supports multiple order type messages, give the message key for
 761          * enabling each one in getNavigationBar.  The return type is an associa-
 762          * tive array whose keys must exactly match the keys of the array returned
 763          * by getIndexField(), and whose values are message keys.
 764          *
 765          * @return Array
 766          */
 767         protected function getOrderTypeMessages() {
 768                 return null;
 769         }
 770 }
 771
 772 /**
 773  * IndexPager with a formatted navigation bar
 774  * @ingroup Pager
 775  */
 776 abstract class ReverseChronologicalPager extends IndexPager {
 777         public $mDefaultDirection = true;
 778         public $mYear;
 779         public $mMonth;
 780
 781         function getNavigationBar() {
 782                 if ( !$this->isNavigationBarShown() ) {
 783                         return '';
 784                 }
 785
 786                 if ( isset( $this->mNavigationBar ) ) {
 787                         return $this->mNavigationBar;
 788                 }
 789
 790                 $linkTexts = array(
 791                         'prev' => $this->msg( 'pager-newer-n' )->numParams( $this->mLimit )->escaped(),
 792                         'next' => $this->msg( 'pager-older-n' )->numParams( $this->mLimit )->escaped(),
 793                         'first' => $this->msg( 'histlast' )->escaped(),
 794                         'last' => $this->msg( 'histfirst' )->escaped()
 795                 );
 796
 797                 $pagingLinks = $this->getPagingLinks( $linkTexts );
 798                 $limitLinks = $this->getLimitLinks();
 799                 $limits = $this->getLanguage()->pipeList( $limitLinks );
 800                 $firstLastLinks = $this->msg( 'parentheses' )->rawParams( "{$pagingLinks['first']}" .
 801                         $this->msg( 'pipe-separator' )->escaped() .
 802                         "{$pagingLinks['last']}" )->escaped();
 803
 804                 $this->mNavigationBar = $firstLastLinks . ' ' .
 805                         $this->msg( 'viewprevnext' )->rawParams(
 806                                 $pagingLinks['prev'], $pagingLinks['next'], $limits )->escaped();
 807
 808                 return $this->mNavigationBar;
 809         }
 810
 811         function getDateCond( $year, $month ) {
 812                 $year = intval( $year );
 813                 $month = intval( $month );
 814
 815                 // Basic validity checks
 816                 $this->mYear = $year > 0 ? $year : false;
 817                 $this->mMonth = ( $month > 0 && $month < 13 ) ? $month : false;
 818
 819                 // Given an optional year and month, we need to generate a timestamp
 820                 // to use as "WHERE rev_timestamp <= result"
 821                 // Examples: year = 2006 equals < 20070101 (+000000)
 822                 // year=2005, month=1    equals < 20050201
 823                 // year=2005, month=12   equals < 20060101
 824                 if ( !$this->mYear && !$this->mMonth ) {
 825                         return;
 826                 }
 827
 828                 if ( $this->mYear ) {
 829                         $year = $this->mYear;
 830                 } else {
 831                         // If no year given, assume the current one
 832                         $year = gmdate( 'Y' );
 833                         // If this month hasn't happened yet this year, go back to last year's month
 834                         if( $this->mMonth > gmdate( 'n' ) ) {
 835                                 $year--;
 836                         }
 837                 }
 838
 839                 if ( $this->mMonth ) {
 840                         $month = $this->mMonth + 1;
 841                         // For December, we want January 1 of the next year
 842                         if ($month > 12) {
 843                                 $month = 1;
 844                                 $year++;
 845                         }
 846                 } else {
 847                         // No month implies we want up to the end of the year in question
 848                         $month = 1;
 849                         $year++;
 850                 }
 851
 852                 // Y2K38 bug
 853                 if ( $year > 2032 ) {
 854                         $year = 2032;
 855                 }
 856
 857                 $ymd = (int)sprintf( "%04d%02d01", $year, $month );
 858
 859                 if ( $ymd > 20320101 ) {
 860                         $ymd = 20320101;
 861                 }
 862
 863                 $this->mOffset = $this->mDb->timestamp( "${ymd}000000" );
 864         }
 865 }
 866
 867 /**
 868  * Table-based display with a user-selectable sort order
 869  * @ingroup Pager
 870  */
 871 abstract class TablePager extends IndexPager {
 872         var $mSort;
 873         var $mCurrentRow;
 874
 875         public function __construct( IContextSource $context = null ) {
 876                 if ( $context ) {
 877                         $this->setContext( $context );
 878                 }
 879
 880                 $this->mSort = $this->getRequest()->getText( 'sort' );
 881                 if ( !array_key_exists( $this->mSort, $this->getFieldNames() ) ) {
 882                         $this->mSort = $this->getDefaultSort();
 883                 }
 884                 if ( $this->getRequest()->getBool( 'asc' ) ) {
 885                         $this->mDefaultDirection = false;
 886                 } elseif ( $this->getRequest()->getBool( 'desc' ) ) {
 887                         $this->mDefaultDirection = true;
 888                 } /* Else leave it at whatever the class default is */
 889
 890                 parent::__construct();
 891         }
 892
 893         /**
 894          * @protected
 895          * @return string
 896          */
 897         function getStartBody() {
 898                 global $wgStylePath;
 899                 $tableClass = htmlspecialchars( $this->getTableClass() );
 900                 $sortClass = htmlspecialchars( $this->getSortHeaderClass() );
 901
 902                 $s = "<table style='border:1;' class=\"mw-datatable $tableClass\"><thead><tr>\n";
 903                 $fields = $this->getFieldNames();
 904
 905                 # Make table header
 906                 foreach ( $fields as $field => $name ) {
 907                         if ( strval( $name ) == '' ) {
 908                                 $s .= "<th>&#160;</th>\n";
 909                         } elseif ( $this->isFieldSortable( $field ) ) {
 910                                 $query = array( 'sort' => $field, 'limit' => $this->mLimit );
 911                                 if ( $field == $this->mSort ) {
 912                                         # This is the sorted column
 913                                         # Prepare a link that goes in the other sort order
 914                                         if ( $this->mDefaultDirection ) {
 915                                                 # Descending
 916                                                 $image = 'Arr_d.png';
 917                                                 $query['asc'] = '1';
 918                                                 $query['desc'] = '';
 919                                                 $alt = $this->msg( 'descending_abbrev' )->escaped();
 920                                         } else {
 921                                                 # Ascending
 922                                                 $image = 'Arr_u.png';
 923                                                 $query['asc'] = '';
 924                                                 $query['desc'] = '1';
 925                                                 $alt = $this->msg( 'ascending_abbrev' )->escaped();
 926                                         }
 927                                         $image = htmlspecialchars( "$wgStylePath/common/images/$image" );
 928                                         $link = $this->makeLink(
 929                                                 "<img width=\"12\" height=\"12\" alt=\"$alt\" src=\"$image\" />" .
 930                                                         htmlspecialchars( $name ), $query );
 931                                         $s .= "<th class=\"$sortClass\">$link</th>\n";
 932                                 } else {
 933                                         $s .= '<th>' . $this->makeLink( htmlspecialchars( $name ), $query ) . "</th>\n";
 934                                 }
 935                         } else {
 936                                 $s .= '<th>' . htmlspecialchars( $name ) . "</th>\n";
 937                         }
 938                 }
 939                 $s .= "</tr></thead><tbody>\n";
 940                 return $s;
 941         }
 942
 943         /**
 944          * @protected
 945          * @return string
 946          */
 947         function getEndBody() {
 948                 return "</tbody></table>\n";
 949         }
 950
 951         /**
 952          * @protected
 953          * @return string
 954          */
 955         function getEmptyBody() {
 956                 $colspan = count( $this->getFieldNames() );
 957                 $msgEmpty = $this->msg( 'table_pager_empty' )->escaped();
 958                 return "<tr><td colspan=\"$colspan\">$msgEmpty</td></tr>\n";
 959         }
 960
 961         /**
 962          * @protected
 963          * @param stdClass $row
 964          * @return String HTML
 965          */
 966         function formatRow( $row ) {
 967                 $this->mCurrentRow = $row; // In case formatValue etc need to know
 968                 $s = Xml::openElement( 'tr', $this->getRowAttrs( $row ) );
 969                 $fieldNames = $this->getFieldNames();
 970
 971                 foreach ( $fieldNames as $field => $name ) {
 972                         $value = isset( $row->$field ) ? $row->$field : null;
 973                         $formatted = strval( $this->formatValue( $field, $value ) );
 974
 975                         if ( $formatted == '' ) {
 976                                 $formatted = '&#160;';
 977                         }
 978
 979                         $s .= Xml::tags( 'td', $this->getCellAttrs( $field, $value ), $formatted );
 980                 }
 981
 982                 $s .= "</tr>\n";
 983
 984                 return $s;
 985         }
 986
 987         /**
 988          * Get a class name to be applied to the given row.
 989          *
 990          * @protected
 991          *
 992          * @param $row Object: the database result row
 993          * @return String
 994          */
 995         function getRowClass( $row ) {
 996                 return '';
 997         }
 998
 999         /**
1000          * Get attributes to be applied to the given row.
1001          *
1002          * @protected
1003          *
1004          * @param $row Object: the database result row
1005          * @return Array of attribute => value
1006          */
1007         function getRowAttrs( $row ) {
1008                 $class = $this->getRowClass( $row );
1009                 if ( $class === '' ) {
1010                         // Return an empty array to avoid clutter in HTML like class=""
1011                         return array();
1012                 } else {
1013                         return array( 'class' => $this->getRowClass( $row ) );
1014                 }
1015         }
1016
1017         /**
1018          * Get any extra attributes to be applied to the given cell. Don't
1019          * take this as an excuse to hardcode styles; use classes and
1020          * CSS instead.  Row context is available in $this->mCurrentRow
1021          *
1022          * @protected
1023          *
1024          * @param $field String The column
1025          * @param $value String The cell contents
1026          * @return Array of attr => value
1027          */
1028         function getCellAttrs( $field, $value ) {
1029                 return array( 'class' => 'TablePager_col_' . $field );
1030         }
1031
1032         /**
1033          * @protected
1034          * @return string
1035          */
1036         function getIndexField() {
1037                 return $this->mSort;
1038         }
1039
1040         /**
1041          * @protected
1042          * @return string
1043          */
1044         function getTableClass() {
1045                 return 'TablePager';
1046         }
1047
1048         /**
1049          * @protected
1050          * @return string
1051          */
1052         function getNavClass() {
1053                 return 'TablePager_nav';
1054         }
1055
1056         /**
1057          * @protected
1058          * @return string
1059          */
1060         function getSortHeaderClass() {
1061                 return 'TablePager_sort';
1062         }
1063
1064         /**
1065          * A navigation bar with images
1066          * @return String HTML
1067          */
1068         public function getNavigationBar() {
1069                 global $wgStylePath;
1070
1071                 if ( !$this->isNavigationBarShown() ) {
1072                         return '';
1073                 }
1074
1075                 $path = "$wgStylePath/common/images";
1076                 $labels = array(
1077                         'first' => 'table_pager_first',
1078                         'prev' => 'table_pager_prev',
1079                         'next' => 'table_pager_next',
1080                         'last' => 'table_pager_last',
1081                 );
1082                 $images = array(
1083                         'first' => 'arrow_first_25.png',
1084                         'prev' => 'arrow_left_25.png',
1085                         'next' => 'arrow_right_25.png',
1086                         'last' => 'arrow_last_25.png',
1087                 );
1088                 $disabledImages = array(
1089                         'first' => 'arrow_disabled_first_25.png',
1090                         'prev' => 'arrow_disabled_left_25.png',
1091                         'next' => 'arrow_disabled_right_25.png',
1092                         'last' => 'arrow_disabled_last_25.png',
1093                 );
1094                 if( $this->getLanguage()->isRTL() ) {
1095                         $keys = array_keys( $labels );
1096                         $images = array_combine( $keys, array_reverse( $images ) );
1097                         $disabledImages = array_combine( $keys, array_reverse( $disabledImages ) );
1098                 }
1099
1100                 $linkTexts = array();
1101                 $disabledTexts = array();
1102                 foreach ( $labels as $type => $label ) {
1103                         $msgLabel = $this->msg( $label )->escaped();
1104                         $linkTexts[$type] = "<img src=\"$path/{$images[$type]}\" alt=\"$msgLabel\"/><br />$msgLabel";
1105                         $disabledTexts[$type] = "<img src=\"$path/{$disabledImages[$type]}\" alt=\"$msgLabel\"/><br />$msgLabel";
1106                 }
1107                 $links = $this->getPagingLinks( $linkTexts, $disabledTexts );
1108
1109                 $navClass = htmlspecialchars( $this->getNavClass() );
1110                 $s = "<table class=\"$navClass\"><tr>\n";
1111                 $width = 100 / count( $links ) . '%';
1112                 foreach ( $labels as $type => $label ) {
1113                         $s .= "<td style='width:$width;'>{$links[$type]}</td>\n";
1114                 }
1115                 $s .= "</tr></table>\n";
1116                 return $s;
1117         }
1118
1119         /**
1120          * Get a "<select>" element which has options for each of the allowed limits
1121          *
1122          * @return String: HTML fragment
1123          */
1124         public function getLimitSelect() {
1125                 # Add the current limit from the query string
1126                 # to avoid that the limit is lost after clicking Go next time
1127                 if ( !in_array( $this->mLimit, $this->mLimitsShown ) ) {
1128                         $this->mLimitsShown[] = $this->mLimit;
1129                         sort( $this->mLimitsShown );
1130                 }
1131                 $s = Html::openElement( 'select', array( 'name' => 'limit' ) ) . "\n";
1132                 foreach ( $this->mLimitsShown as $key => $value ) {
1133                         # The pair is either $index => $limit, in which case the $value
1134                         # will be numeric, or $limit => $text, in which case the $value
1135                         # will be a string.
1136                         if( is_int( $value ) ){
1137                                 $limit = $value;
1138                                 $text = $this->getLanguage()->formatNum( $limit );
1139                         } else {
1140                                 $limit = $key;
1141                                 $text = $value;
1142                         }
1143                         $s .= Xml::option( $text, $limit, $limit == $this->mLimit ) . "\n";
1144                 }
1145                 $s .= Html::closeElement( 'select' );
1146                 return $s;
1147         }
1148
1149         /**
1150          * Get \<input type="hidden"\> elements for use in a method="get" form.
1151          * Resubmits all defined elements of the query string, except for a
1152          * blacklist, passed in the $blacklist parameter.
1153          *
1154          * @param $blacklist Array parameters from the request query which should not be resubmitted
1155          * @return String: HTML fragment
1156          */
1157         function getHiddenFields( $blacklist = array() ) {
1158                 $blacklist = (array)$blacklist;
1159                 $query = $this->getRequest()->getQueryValues();
1160                 foreach ( $blacklist as $name ) {
1161                         unset( $query[$name] );
1162                 }
1163                 $s = '';
1164                 foreach ( $query as $name => $value ) {
1165                         $encName = htmlspecialchars( $name );
1166                         $encValue = htmlspecialchars( $value );
1167                         $s .= "<input type=\"hidden\" name=\"$encName\" value=\"$encValue\"/>\n";
1168                 }
1169                 return $s;
1170         }
1171
1172         /**
1173          * Get a form containing a limit selection dropdown
1174          *
1175          * @return String: HTML fragment
1176          */
1177         function getLimitForm() {
1178                 global $wgScript;
1179
1180                 return Xml::openElement(
1181                         'form',
1182                         array(
1183                                 'method' => 'get',
1184                                 'action' => $wgScript
1185                         ) ) . "\n" . $this->getLimitDropdown() . "</form>\n";
1186         }
1187
1188         /**
1189          * Gets a limit selection dropdown
1190          *
1191          * @return string
1192          */
1193         function getLimitDropdown() {
1194                 # Make the select with some explanatory text
1195                 $msgSubmit = $this->msg( 'table_pager_limit_submit' )->escaped();
1196
1197                 return $this->msg( 'table_pager_limit' )
1198                         ->rawParams( $this->getLimitSelect() )->escaped() .
1199                         "\n<input type=\"submit\" value=\"$msgSubmit\"/>\n" .
1200                         $this->getHiddenFields( array( 'limit' ) );
1201         }
1202
1203         /**
1204          * Return true if the named field should be sortable by the UI, false
1205          * otherwise
1206          *
1207          * @param $field String
1208          */
1209         abstract function isFieldSortable( $field );
1210
1211         /**
1212          * Format a table cell. The return value should be HTML, but use an empty
1213          * string not &#160; for empty cells. Do not include the <td> and </td>.
1214          *
1215          * The current result row is available as $this->mCurrentRow, in case you
1216          * need more context.
1217          *
1218          * @protected
1219          *
1220          * @param $name String: the database field name
1221          * @param $value String: the value retrieved from the database
1222          */
1223         abstract function formatValue( $name, $value );
1224
1225         /**
1226          * The database field name used as a default sort order.
1227          *
1228          * @protected
1229          *
1230          * @return string
1231          */
1232         abstract function getDefaultSort();
1233
1234         /**
1235          * An array mapping database field names to a textual description of the
1236          * field name, for use in the table header. The description should be plain
1237          * text, it will be HTML-escaped later.
1238          *
1239          * @return Array
1240          */
1241         abstract function getFieldNames();
1242 }