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IndexPager.php
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1 <?php
29 
72 abstract class IndexPager extends ContextSource implements Pager {
74  const DIR_ASCENDING = false;
76  const DIR_DESCENDING = true;
77 
79  const QUERY_ASCENDING = true;
81  const QUERY_DESCENDING = false;
82 
84  public $mRequest;
86  public $mLimitsShown = [ 20, 50, 100, 250, 500 ];
88  public $mDefaultLimit = 50;
90  public $mOffset;
92  public $mLimit;
94  public $mQueryDone = false;
96  public $mDb;
99 
105  protected $mIndexField;
111  protected $mExtraSortFields;
115  protected $mOrderType;
131 
133  public $mIsFirst;
135  public $mIsLast;
136 
138  protected $mLastShown;
140  protected $mFirstShown;
142  protected $mPastTheEndIndex;
144  protected $mDefaultQuery;
146  protected $mNavigationBar;
147 
152  protected $mIncludeOffset = false;
153 
159  public $mResult;
160 
162  private $linkRenderer;
163 
164  public function __construct( IContextSource $context = null, LinkRenderer $linkRenderer = null ) {
165  if ( $context ) {
166  $this->setContext( $context );
167  }
168 
169  $this->mRequest = $this->getRequest();
170 
171  # NB: the offset is quoted, not validated. It is treated as an
172  # arbitrary string to support the widest variety of index types. Be
173  # careful outputting it into HTML!
174  $this->mOffset = $this->mRequest->getText( 'offset' );
175 
176  # Use consistent behavior for the limit options
177  $this->mDefaultLimit = $this->getUser()->getIntOption( 'rclimit' );
178  if ( !$this->mLimit ) {
179  // Don't override if a subclass calls $this->setLimit() in its constructor.
180  list( $this->mLimit, /* $offset */ ) = $this->mRequest->getLimitOffset();
181  }
182 
183  $this->mIsBackwards = ( $this->mRequest->getVal( 'dir' ) == 'prev' );
184  # Let the subclass set the DB here; otherwise use a replica DB for the current wiki
185  $this->mDb = $this->mDb ?: wfGetDB( DB_REPLICA );
186 
187  $index = $this->getIndexField(); // column to sort on
188  $extraSort = $this->getExtraSortFields(); // extra columns to sort on for query planning
189  $order = $this->mRequest->getVal( 'order' );
190  if ( is_array( $index ) && isset( $index[$order] ) ) {
191  $this->mOrderType = $order;
192  $this->mIndexField = $index[$order];
193  $this->mExtraSortFields = isset( $extraSort[$order] )
194  ? (array)$extraSort[$order]
195  : [];
196  } elseif ( is_array( $index ) ) {
197  # First element is the default
198  $this->mIndexField = reset( $index );
199  $this->mOrderType = key( $index );
200  $this->mExtraSortFields = isset( $extraSort[$this->mOrderType] )
201  ? (array)$extraSort[$this->mOrderType]
202  : [];
203  } else {
204  # $index is not an array
205  $this->mOrderType = null;
206  $this->mIndexField = $index;
207  $this->mExtraSortFields = (array)$extraSort;
208  }
209 
210  if ( !isset( $this->mDefaultDirection ) ) {
211  $dir = $this->getDefaultDirections();
212  $this->mDefaultDirection = is_array( $dir )
213  ? $dir[$this->mOrderType]
214  : $dir;
215  }
216  $this->linkRenderer = $linkRenderer;
217  }
218 
224  public function getDatabase() {
225  return $this->mDb;
226  }
227 
233  public function doQuery() {
234  # Use the child class name for profiling
235  $fname = __METHOD__ . ' (' . static::class . ')';
237  $section = Profiler::instance()->scopedProfileIn( $fname );
238 
239  $defaultOrder = ( $this->mDefaultDirection === self::DIR_ASCENDING )
240  ? self::QUERY_ASCENDING
241  : self::QUERY_DESCENDING;
242  $order = $this->mIsBackwards ? self::oppositeOrder( $defaultOrder ) : $defaultOrder;
243 
244  # Plus an extra row so that we can tell the "next" link should be shown
245  $queryLimit = $this->mLimit + 1;
246 
247  if ( $this->mOffset == '' ) {
248  $isFirst = true;
249  } else {
250  // If there's an offset, we may or may not be at the first entry.
251  // The only way to tell is to run the query in the opposite
252  // direction see if we get a row.
253  $oldIncludeOffset = $this->mIncludeOffset;
254  $this->mIncludeOffset = !$this->mIncludeOffset;
255  $oppositeOrder = self::oppositeOrder( $order );
256  $isFirst = !$this->reallyDoQuery( $this->mOffset, 1, $oppositeOrder )->numRows();
257  $this->mIncludeOffset = $oldIncludeOffset;
258  }
259 
260  $this->mResult = $this->reallyDoQuery(
261  $this->mOffset,
262  $queryLimit,
263  $order
264  );
265 
266  $this->extractResultInfo( $isFirst, $queryLimit, $this->mResult );
267  $this->mQueryDone = true;
268 
269  $this->preprocessResults( $this->mResult );
270  $this->mResult->rewind(); // Paranoia
271  }
272 
277  final protected static function oppositeOrder( $order ) {
278  return ( $order === self::QUERY_ASCENDING )
279  ? self::QUERY_DESCENDING
280  : self::QUERY_ASCENDING;
281  }
282 
286  function getResult() {
287  return $this->mResult;
288  }
289 
295  function setOffset( $offset ) {
296  $this->mOffset = $offset;
297  }
298 
306  function setLimit( $limit ) {
307  $limit = (int)$limit;
308  // WebRequest::getLimitOffset() puts a cap of 5000, so do same here.
309  if ( $limit > 5000 ) {
310  $limit = 5000;
311  }
312  if ( $limit > 0 ) {
313  $this->mLimit = $limit;
314  }
315  }
316 
322  function getLimit() {
323  return $this->mLimit;
324  }
325 
333  public function setIncludeOffset( $include ) {
334  $this->mIncludeOffset = $include;
335  }
336 
346  function extractResultInfo( $isFirst, $limit, IResultWrapper $res ) {
347  $numRows = $res->numRows();
348  if ( $numRows ) {
349  # Remove any table prefix from index field
350  $parts = explode( '.', $this->mIndexField );
351  $indexColumn = end( $parts );
352 
353  $row = $res->fetchRow();
354  $firstIndex = $row[$indexColumn];
355 
356  # Discard the extra result row if there is one
357  if ( $numRows > $this->mLimit && $numRows > 1 ) {
358  $res->seek( $numRows - 1 );
359  $this->mPastTheEndRow = $res->fetchObject();
360  $this->mPastTheEndIndex = $this->mPastTheEndRow->$indexColumn;
361  $res->seek( $numRows - 2 );
362  $row = $res->fetchRow();
363  $lastIndex = $row[$indexColumn];
364  } else {
365  $this->mPastTheEndRow = null;
366  # Setting indexes to an empty string means that they will be
367  # omitted if they would otherwise appear in URLs. It just so
368  # happens that this is the right thing to do in the standard
369  # UI, in all the relevant cases.
370  $this->mPastTheEndIndex = '';
371  $res->seek( $numRows - 1 );
372  $row = $res->fetchRow();
373  $lastIndex = $row[$indexColumn];
374  }
375  } else {
376  $firstIndex = '';
377  $lastIndex = '';
378  $this->mPastTheEndRow = null;
379  $this->mPastTheEndIndex = '';
380  }
381 
382  if ( $this->mIsBackwards ) {
383  $this->mIsFirst = ( $numRows < $limit );
384  $this->mIsLast = $isFirst;
385  $this->mLastShown = $firstIndex;
386  $this->mFirstShown = $lastIndex;
387  } else {
388  $this->mIsFirst = $isFirst;
389  $this->mIsLast = ( $numRows < $limit );
390  $this->mLastShown = $lastIndex;
391  $this->mFirstShown = $firstIndex;
392  }
393  }
394 
400  function getSqlComment() {
401  return static::class;
402  }
403 
414  public function reallyDoQuery( $offset, $limit, $order ) {
415  list( $tables, $fields, $conds, $fname, $options, $join_conds ) =
416  $this->buildQueryInfo( $offset, $limit, $order );
417 
418  return $this->mDb->select( $tables, $fields, $conds, $fname, $options, $join_conds );
419  }
420 
431  protected function buildQueryInfo( $offset, $limit, $order ) {
432  $fname = __METHOD__ . ' (' . $this->getSqlComment() . ')';
433  $info = $this->getQueryInfo();
434  $tables = $info['tables'];
435  $fields = $info['fields'];
436  $conds = $info['conds'] ?? [];
437  $options = $info['options'] ?? [];
438  $join_conds = $info['join_conds'] ?? [];
439  $sortColumns = array_merge( [ $this->mIndexField ], $this->mExtraSortFields );
440  if ( $order === self::QUERY_ASCENDING ) {
441  $options['ORDER BY'] = $sortColumns;
442  $operator = $this->mIncludeOffset ? '>=' : '>';
443  } else {
444  $orderBy = [];
445  foreach ( $sortColumns as $col ) {
446  $orderBy[] = $col . ' DESC';
447  }
448  $options['ORDER BY'] = $orderBy;
449  $operator = $this->mIncludeOffset ? '<=' : '<';
450  }
451  if ( $offset != '' ) {
452  $conds[] = $this->mIndexField . $operator . $this->mDb->addQuotes( $offset );
453  }
454  $options['LIMIT'] = intval( $limit );
455  return [ $tables, $fields, $conds, $fname, $options, $join_conds ];
456  }
457 
463  protected function preprocessResults( $result ) {
464  }
465 
472  public function getBody() {
473  if ( !$this->mQueryDone ) {
474  $this->doQuery();
475  }
476 
477  if ( $this->mResult->numRows() ) {
478  # Do any special query batches before display
479  $this->doBatchLookups();
480  }
481 
482  # Don't use any extra rows returned by the query
483  $numRows = min( $this->mResult->numRows(), $this->mLimit );
484 
485  $s = $this->getStartBody();
486  if ( $numRows ) {
487  if ( $this->mIsBackwards ) {
488  for ( $i = $numRows - 1; $i >= 0; $i-- ) {
489  $this->mResult->seek( $i );
490  $row = $this->mResult->fetchObject();
491  $s .= $this->formatRow( $row );
492  }
493  } else {
494  $this->mResult->seek( 0 );
495  for ( $i = 0; $i < $numRows; $i++ ) {
496  $row = $this->mResult->fetchObject();
497  $s .= $this->formatRow( $row );
498  }
499  }
500  } else {
501  $s .= $this->getEmptyBody();
502  }
503  $s .= $this->getEndBody();
504  return $s;
505  }
506 
516  function makeLink( $text, array $query = null, $type = null ) {
517  if ( $query === null ) {
518  return $text;
519  }
520 
521  $attrs = [];
522  if ( in_array( $type, [ 'prev', 'next' ] ) ) {
523  $attrs['rel'] = $type;
524  }
525 
526  if ( in_array( $type, [ 'asc', 'desc' ] ) ) {
527  $attrs['title'] = $this->msg( $type == 'asc' ? 'sort-ascending' : 'sort-descending' )->text();
528  }
529 
530  if ( $type ) {
531  $attrs['class'] = "mw-{$type}link";
532  }
533 
534  return $this->getLinkRenderer()->makeKnownLink(
535  $this->getTitle(),
536  new HtmlArmor( $text ),
537  $attrs,
538  $query + $this->getDefaultQuery()
539  );
540  }
541 
549  protected function doBatchLookups() {
550  }
551 
558  protected function getStartBody() {
559  return '';
560  }
561 
567  protected function getEndBody() {
568  return '';
569  }
570 
577  protected function getEmptyBody() {
578  return '';
579  }
580 
588  function getDefaultQuery() {
589  if ( !isset( $this->mDefaultQuery ) ) {
590  $this->mDefaultQuery = $this->getRequest()->getQueryValues();
591  unset( $this->mDefaultQuery['title'] );
592  unset( $this->mDefaultQuery['dir'] );
593  unset( $this->mDefaultQuery['offset'] );
594  unset( $this->mDefaultQuery['limit'] );
595  unset( $this->mDefaultQuery['order'] );
596  unset( $this->mDefaultQuery['month'] );
597  unset( $this->mDefaultQuery['year'] );
598  }
599  return $this->mDefaultQuery;
600  }
601 
607  function getNumRows() {
608  if ( !$this->mQueryDone ) {
609  $this->doQuery();
610  }
611  return $this->mResult->numRows();
612  }
613 
619  function getPagingQueries() {
620  if ( !$this->mQueryDone ) {
621  $this->doQuery();
622  }
623 
624  # Don't announce the limit everywhere if it's the default
625  $urlLimit = $this->mLimit == $this->mDefaultLimit ? null : $this->mLimit;
626 
627  if ( $this->mIsFirst ) {
628  $prev = false;
629  $first = false;
630  } else {
631  $prev = [
632  'dir' => 'prev',
633  'offset' => $this->mFirstShown,
634  'limit' => $urlLimit
635  ];
636  $first = [ 'limit' => $urlLimit ];
637  }
638  if ( $this->mIsLast ) {
639  $next = false;
640  $last = false;
641  } else {
642  $next = [ 'offset' => $this->mLastShown, 'limit' => $urlLimit ];
643  $last = [ 'dir' => 'prev', 'limit' => $urlLimit ];
644  }
645  return [
646  'prev' => $prev,
647  'next' => $next,
648  'first' => $first,
649  'last' => $last
650  ];
651  }
652 
658  function isNavigationBarShown() {
659  if ( !$this->mQueryDone ) {
660  $this->doQuery();
661  }
662  // Hide navigation by default if there is nothing to page
663  return !( $this->mIsFirst && $this->mIsLast );
664  }
665 
676  function getPagingLinks( $linkTexts, $disabledTexts = [] ) {
677  $queries = $this->getPagingQueries();
678  $links = [];
679 
680  foreach ( $queries as $type => $query ) {
681  if ( $query !== false ) {
682  $links[$type] = $this->makeLink(
683  $linkTexts[$type],
684  $queries[$type],
685  $type
686  );
687  } elseif ( isset( $disabledTexts[$type] ) ) {
688  $links[$type] = $disabledTexts[$type];
689  } else {
690  $links[$type] = $linkTexts[$type];
691  }
692  }
693 
694  return $links;
695  }
696 
697  function getLimitLinks() {
698  $links = [];
699  if ( $this->mIsBackwards ) {
700  $offset = $this->mPastTheEndIndex;
701  } else {
702  $offset = $this->mOffset;
703  }
704  foreach ( $this->mLimitsShown as $limit ) {
705  $links[] = $this->makeLink(
706  $this->getLanguage()->formatNum( $limit ),
707  [ 'offset' => $offset, 'limit' => $limit ],
708  'num'
709  );
710  }
711  return $links;
712  }
713 
722  abstract function formatRow( $row );
723 
736  abstract function getQueryInfo();
737 
750  abstract function getIndexField();
751 
768  protected function getExtraSortFields() {
769  return [];
770  }
771 
791  protected function getDefaultDirections() {
792  return self::DIR_ASCENDING;
793  }
794 
805  protected function buildPrevNextNavigation( Title $title, $offset, $limit,
806  array $query = [], $atend = false
807  ) {
808  $prevNext = new PrevNextNavigationRenderer( $this );
809 
810  return $prevNext->buildPrevNextNavigation( $title, $offset, $limit, $query, $atend );
811  }
812 
813  protected function getLinkRenderer() {
814  if ( $this->linkRenderer === null ) {
815  $this->linkRenderer = MediaWikiServices::getInstance()->getLinkRenderer();
816  }
817  return $this->linkRenderer;
818  }
819 }
const DIR_DESCENDING
Backwards-compatible constant for $mDefaultDirection field (do not change)
Definition: IndexPager.php:76
setContext(IContextSource $context)
setOffset( $offset)
Set the offset from an other source than the request.
Definition: IndexPager.php:295
buildPrevNextNavigation(Title $title, $offset, $limit, array $query=[], $atend=false)
Generate (prev x| next x) (20|50|100...) type links for paging.
Definition: IndexPager.php:805
mixed $mOffset
The starting point to enumerate entries.
Definition: IndexPager.php:90
fetchObject()
Fetch the next row from the given result object, in object form.
preprocessResults( $result)
Pre-process results; useful for performing batch existence checks, etc.
Definition: IndexPager.php:463
Helper class for generating prev/next links for paging.
formatRow( $row)
Abstract formatting function.
getIndexField()
This function should be overridden to return the name of the index fi- eld.
bool $mDefaultDirection
$mDefaultDirection gives the direction to use when sorting results: DIR_ASCENDING or DIR_DESCENDING...
Definition: IndexPager.php:128
The simplest way of implementing IContextSource is to hold a RequestContext as a member variable and ...
int [] $mLimitsShown
List of default entry limit options to be presented to clients.
Definition: IndexPager.php:86
static instance()
Singleton.
Definition: Profiler.php:63
buildQueryInfo( $offset, $limit, $order)
Build variables to use by the database wrapper.
Definition: IndexPager.php:431
wfGetDB( $db, $groups=[], $wiki=false)
Get a Database object.
bool $mIsLast
Definition: IndexPager.php:135
__construct(IContextSource $context=null, LinkRenderer $linkRenderer=null)
Definition: IndexPager.php:164
static oppositeOrder( $order)
Definition: IndexPager.php:277
getPagingLinks( $linkTexts, $disabledTexts=[])
Get paging links.
Definition: IndexPager.php:676
doQuery()
Do the query, using information from the object context.
Definition: IndexPager.php:233
string $mIndexField
The index to actually be used for ordering.
Definition: IndexPager.php:105
LinkRenderer $linkRenderer
Definition: IndexPager.php:162
extractResultInfo( $isFirst, $limit, IResultWrapper $res)
Extract some useful data from the result object for use by the navigation bar, put it into $this...
Definition: IndexPager.php:346
IContextSource $context
getDatabase()
Get the Database object in use.
Definition: IndexPager.php:224
bool $mQueryDone
Whether the listing query completed.
Definition: IndexPager.php:94
$last
doBatchLookups()
Called from getBody(), before getStartBody() is called and after doQuery() was called.
Definition: IndexPager.php:549
IndexPager is an efficient pager which uses a (roughly unique) index in the data set to implement pag...
Definition: IndexPager.php:72
bool $mIncludeOffset
Whether to include the offset in the query.
Definition: IndexPager.php:152
mixed $mLastShown
Definition: IndexPager.php:138
makeLink( $text, array $query=null, $type=null)
Make a self-link.
Definition: IndexPager.php:516
mixed $mPastTheEndIndex
Definition: IndexPager.php:142
getEmptyBody()
Hook into getBody(), for the bit between the start and the end when there are no rows.
Definition: IndexPager.php:577
getSqlComment()
Get some text to go in brackets in the "function name" part of the SQL comment.
Definition: IndexPager.php:400
Basic pager interface.
Definition: Pager.php:32
WebRequest $mRequest
Definition: IndexPager.php:84
Class that generates HTML links for pages.
getExtraSortFields()
This function should be overridden to return the names of secondary columns to order by in addition t...
Definition: IndexPager.php:768
getStartBody()
Hook into getBody(), allows text to be inserted at the start.
Definition: IndexPager.php:558
IDatabase $mDb
Definition: IndexPager.php:96
bool $mIsBackwards
Definition: IndexPager.php:130
const QUERY_ASCENDING
Backwards-compatible constant for reallyDoQuery() (do not change)
Definition: IndexPager.php:79
reallyDoQuery( $offset, $limit, $order)
Do a query with specified parameters, rather than using the object context.
Definition: IndexPager.php:414
isNavigationBarShown()
Returns whether to show the "navigation bar".
Definition: IndexPager.php:658
getLimit()
Get the current limit.
Definition: IndexPager.php:322
string $mNavigationBar
Definition: IndexPager.php:146
Result wrapper for grabbing data queried from an IDatabase object.
IResultWrapper $mResult
Result object for the query.
Definition: IndexPager.php:159
getQueryInfo()
This function should be overridden to provide all parameters needed for the main paged query...
mixed $mFirstShown
Definition: IndexPager.php:140
numRows()
Get the number of rows in a result object.
const QUERY_DESCENDING
Backwards-compatible constant for reallyDoQuery() (do not change)
Definition: IndexPager.php:81
seek( $pos)
Change the position of the cursor in a result object.
stdClass bool null $mPastTheEndRow
Extra row fetched at the end to see if the end was reached.
Definition: IndexPager.php:98
msg( $key,... $params)
Get a Message object with context set Parameters are the same as wfMessage()
getDefaultQuery()
Get an array of query parameters that should be put into self-links.
Definition: IndexPager.php:588
fetchRow()
Fetch the next row from the given result object, in associative array form.
setLimit( $limit)
Set the limit from an other source than the request.
Definition: IndexPager.php:306
setIncludeOffset( $include)
Set whether a row matching exactly the offset should be also included in the result or not...
Definition: IndexPager.php:333
bool $mIsFirst
True if the current result set is the first one.
Definition: IndexPager.php:133
const DB_REPLICA
Definition: defines.php:25
int $mDefaultLimit
The default entry limit choosen for clients.
Definition: IndexPager.php:88
getBody()
Get the formatted result list.
Definition: IndexPager.php:472
getDefaultDirections()
Return the default sorting direction: DIR_ASCENDING or DIR_DESCENDING.
Definition: IndexPager.php:791
getPagingQueries()
Get a URL query array for the prev, next, first and last links.
Definition: IndexPager.php:619
$queries
string [] $mExtraSortFields
An array of secondary columns to order by.
Definition: IndexPager.php:111
string null $mOrderType
For pages that support multiple types of ordering, which one to use.
Definition: IndexPager.php:115
const DIR_ASCENDING
Backwards-compatible constant for $mDefaultDirection field (do not change)
Definition: IndexPager.php:74
array $mDefaultQuery
Definition: IndexPager.php:144
getNumRows()
Get the number of rows in the result set.
Definition: IndexPager.php:607
getEndBody()
Hook into getBody() for the end of the list.
Definition: IndexPager.php:567
int $mLimit
The maximum number of entries to show.
Definition: IndexPager.php:92