4 * Basic pager interface.
7 function getNavigationBar();
12 * IndexPager is an efficient pager which uses a (roughly unique) index in the
13 * data set to implement paging, rather than a "LIMIT offset,limit" clause.
14 * In MySQL, such a limit/offset clause requires counting through the specified number
15 * of offset rows to find the desired data, which can be expensive for large offsets.
17 * ReverseChronologicalPager is a child class of the abstract IndexPager, and contains
18 * some formatting and display code which is specific to the use of timestamps as
19 * indexes. Here is a synopsis of its operation:
21 * * The query is specified by the offset, limit and direction (dir) parameters, in
22 * addition to any subclass-specific parameters.
24 * * The offset is the non-inclusive start of the DB query. A row with an index value
25 * equal to the offset will never be shown.
27 * * The query may either be done backwards, where the rows are returned by the database
28 * in the opposite order to which they are displayed to the user, or forwards. This is
29 * specified by the "dir" parameter, dir=prev means backwards, anything else means
30 * forwards. The offset value specifies the start of the database result set, which
31 * may be either the start or end of the displayed data set. This allows "previous"
32 * links to be implemented without knowledge of the index value at the start of the
35 * * An additional row beyond the user-specified limit is always requested. This allows
36 * us to tell whether we should display a "next" link in the case of forwards mode,
37 * or a "previous" link in the case of backwards mode. Determining whether to
38 * display the other link (the one for the page before the start of the database
39 * result set) can be done heuristically by examining the offset.
41 * * An empty offset indicates that the offset condition should be omitted from the query.
42 * This naturally produces either the first page or the last page depending on the
45 * Subclassing the pager to implement concrete functionality should be fairly simple,
46 * please see the examples in PageHistory.php and SpecialIpblocklist.php. You just need
47 * to override formatRow(), getQueryInfo() and getIndexField(). Don't forget to call the
48 * parent constructor if you override it.
50 abstract class IndexPager
implements Pager
{
52 public $mLimitsShown = array( 20, 50, 100, 250, 500 );
53 public $mDefaultLimit = 50;
54 public $mOffset, $mLimit;
55 public $mQueryDone = false;
57 public $mPastTheEndRow;
59 protected $mIndexField;
62 * Default query direction. false for ascending, true for descending
64 public $mDefaultDirection = false;
67 * Result object for the query. Warning: seek before use.
71 function __construct() {
73 $this->mRequest
= $wgRequest;
75 # NB: the offset is quoted, not validated. It is treated as an arbitrary string
76 # to support the widest variety of index types. Be careful outputting it into
78 $this->mOffset
= $this->mRequest
->getText( 'offset' );
79 $this->mLimit
= $this->mRequest
->getInt( 'limit', $this->mDefaultLimit
);
80 if ( $this->mLimit
<= 0 ) {
81 $this->mLimit
= $this->mDefaultLimit
;
83 $this->mIsBackwards
= ( $this->mRequest
->getVal( 'dir' ) == 'prev' );
84 $this->mIndexField
= $this->getIndexField();
85 $this->mDb
= wfGetDB( DB_SLAVE
);
89 * Do the query, using information from the object context. This function
90 * has been kept minimal to make it overridable if necessary, to allow for
91 * result sets formed from multiple DB queries.
94 # Use the child class name for profiling
95 $fname = __METHOD__
. ' (' . get_class( $this ) . ')';
96 wfProfileIn( $fname );
98 $descending = ( $this->mIsBackwards
== $this->mDefaultDirection
);
99 # Plus an extra row so that we can tell the "next" link should be shown
100 $queryLimit = $this->mLimit +
1;
102 $this->mResult
= $this->reallyDoQuery( $this->mOffset
, $queryLimit, $descending );
103 $this->extractResultInfo( $this->mOffset
, $queryLimit, $this->mResult
);
104 $this->mQueryDone
= true;
106 wfProfileOut( $fname );
110 * Extract some useful data from the result object for use by
111 * the navigation bar, put it into $this
113 function extractResultInfo( $offset, $limit, ResultWrapper
$res ) {
114 $numRows = $res->numRows();
116 $row = $res->fetchRow();
117 $firstIndex = $row[$this->mIndexField
];
119 # Discard the extra result row if there is one
120 if ( $numRows > $this->mLimit
&& $numRows > 1 ) {
121 $res->seek( $numRows - 1 );
122 $this->mPastTheEndRow
= $res->fetchObject();
123 $indexField = $this->mIndexField
;
124 $this->mPastTheEndIndex
= $this->mPastTheEndRow
->$indexField;
125 $res->seek( $numRows - 2 );
126 $row = $res->fetchRow();
127 $lastIndex = $row[$this->mIndexField
];
129 $this->mPastTheEndRow
= null;
130 # Setting indexes to an empty string means that they will be omitted
131 # if they would otherwise appear in URLs. It just so happens that this
132 # is the right thing to do in the standard UI, in all the relevant cases.
133 $this->mPastTheEndIndex
= '';
134 $res->seek( $numRows - 1 );
135 $row = $res->fetchRow();
136 $lastIndex = $row[$this->mIndexField
];
141 $this->mPastTheEndRow
= null;
142 $this->mPastTheEndIndex
= '';
145 if ( $this->mIsBackwards
) {
146 $this->mIsFirst
= ( $numRows < $limit );
147 $this->mIsLast
= ( $offset == '' );
148 $this->mLastShown
= $firstIndex;
149 $this->mFirstShown
= $lastIndex;
151 $this->mIsFirst
= ( $offset == '' );
152 $this->mIsLast
= ( $numRows < $limit );
153 $this->mLastShown
= $lastIndex;
154 $this->mFirstShown
= $firstIndex;
159 * Do a query with specified parameters, rather than using the object context
161 * @param string $offset Index offset, inclusive
162 * @param integer $limit Exact query limit
163 * @param boolean $descending Query direction, false for ascending, true for descending
164 * @return ResultWrapper
166 function reallyDoQuery( $offset, $limit, $ascending ) {
167 $fname = __METHOD__
. ' (' . get_class( $this ) . ')';
168 $info = $this->getQueryInfo();
169 $tables = $info['tables'];
170 $fields = $info['fields'];
171 $conds = isset( $info['conds'] ) ?
$info['conds'] : array();
172 $options = isset( $info['options'] ) ?
$info['options'] : array();
174 $options['ORDER BY'] = $this->mIndexField
;
177 $options['ORDER BY'] = $this->mIndexField
. ' DESC';
180 if ( $offset != '' ) {
181 $conds[] = $this->mIndexField
. $operator . $this->mDb
->addQuotes( $offset );
183 $options['LIMIT'] = intval( $limit );
184 $res = $this->mDb
->select( $tables, $fields, $conds, $fname, $options );
185 return new ResultWrapper( $this->mDb
, $res );
189 * Get the formatted result list. Calls getStartBody(), formatRow() and
190 * getEndBody(), concatenates the results and returns them.
193 if ( !$this->mQueryDone
) {
196 # Don't use any extra rows returned by the query
197 $numRows = min( $this->mResult
->numRows(), $this->mLimit
);
199 $s = $this->getStartBody();
201 if ( $this->mIsBackwards
) {
202 for ( $i = $numRows - 1; $i >= 0; $i-- ) {
203 $this->mResult
->seek( $i );
204 $row = $this->mResult
->fetchObject();
205 $s .= $this->formatRow( $row );
208 $this->mResult
->seek( 0 );
209 for ( $i = 0; $i < $numRows; $i++
) {
210 $row = $this->mResult
->fetchObject();
211 $s .= $this->formatRow( $row );
215 $s .= $this->getEmptyBody();
217 $s .= $this->getEndBody();
224 function makeLink($text, $query = NULL) {
225 if ( $query === null ) {
228 return $this->getSkin()->makeKnownLinkObj( $this->getTitle(), $text,
229 wfArrayToCGI( $query, $this->getDefaultQuery() ) );
234 * Hook into getBody(), allows text to be inserted at the start. This
235 * will be called even if there are no rows in the result set.
237 function getStartBody() {
242 * Hook into getBody() for the end of the list
244 function getEndBody() {
249 * Hook into getBody(), for the bit between the start and the
250 * end when there are no rows
252 function getEmptyBody() {
257 * Title used for self-links. Override this if you want to be able to
258 * use a title other than $wgTitle
260 function getTitle() {
261 return $GLOBALS['wgTitle'];
265 * Get the current skin. This can be overridden if necessary.
268 if ( !isset( $this->mSkin
) ) {
270 $this->mSkin
= $wgUser->getSkin();
276 * Get an array of query parameters that should be put into self-links.
277 * By default, all parameters passed in the URL are used, except for a
280 function getDefaultQuery() {
281 if ( !isset( $this->mDefaultQuery
) ) {
282 $this->mDefaultQuery
= $_GET;
283 unset( $this->mDefaultQuery
['title'] );
284 unset( $this->mDefaultQuery
['dir'] );
285 unset( $this->mDefaultQuery
['offset'] );
286 unset( $this->mDefaultQuery
['limit'] );
288 return $this->mDefaultQuery
;
292 * Get the number of rows in the result set
294 function getNumRows() {
295 if ( !$this->mQueryDone
) {
298 return $this->mResult
->numRows();
302 * Get a query array for the prev, next, first and last links.
304 function getPagingQueries() {
305 if ( !$this->mQueryDone
) {
309 # Don't announce the limit everywhere if it's the default
310 $urlLimit = $this->mLimit
== $this->mDefaultLimit ?
'' : $this->mLimit
;
312 if ( $this->mIsFirst
) {
316 $prev = array( 'dir' => 'prev', 'offset' => $this->mFirstShown
, 'limit' => $urlLimit );
317 $first = array( 'limit' => $urlLimit );
319 if ( $this->mIsLast
) {
323 $next = array( 'offset' => $this->mLastShown
, 'limit' => $urlLimit );
324 $last = array( 'dir' => 'prev', 'limit' => $urlLimit );
326 return compact( 'prev', 'next', 'first', 'last' );
330 * Get paging links. If a link is disabled, the item from $disabledTexts will
331 * be used. If there is no such item, the unlinked text from $linkTexts will
332 * be used. Both $linkTexts and $disabledTexts are arrays of HTML.
334 function getPagingLinks( $linkTexts, $disabledTexts = array() ) {
335 $queries = $this->getPagingQueries();
337 foreach ( $queries as $type => $query ) {
338 if ( $query !== false ) {
339 $links[$type] = $this->makeLink( $linkTexts[$type], $queries[$type] );
340 } elseif ( isset( $disabledTexts[$type] ) ) {
341 $links[$type] = $disabledTexts[$type];
343 $links[$type] = $linkTexts[$type];
349 function getLimitLinks() {
352 if ( $this->mIsBackwards
) {
353 $offset = $this->mPastTheEndIndex
;
355 $offset = $this->mOffset
;
357 foreach ( $this->mLimitsShown
as $limit ) {
358 $links[] = $this->makeLink( $wgLang->formatNum( $limit ),
359 array( 'offset' => $offset, 'limit' => $limit ) );
365 * Abstract formatting function. This should return an HTML string
366 * representing the result row $row. Rows will be concatenated and
367 * returned by getBody()
369 abstract function formatRow( $row );
372 * This function should be overridden to provide all parameters
373 * needed for the main paged query. It returns an associative
374 * array with the following elements:
375 * tables => Table(s) for passing to Database::select()
376 * fields => Field(s) for passing to Database::select(), may be *
377 * conds => WHERE conditions
378 * options => option array
380 abstract function getQueryInfo();
383 * This function should be overridden to return the name of the
386 abstract function getIndexField();
390 * IndexPager with a formatted navigation bar
392 abstract class ReverseChronologicalPager
extends IndexPager
{
393 public $mDefaultDirection = true;
395 function __construct() {
396 parent
::__construct();
399 function getNavigationBar() {
402 if ( isset( $this->mNavigationBar
) ) {
403 return $this->mNavigationBar
;
406 'prev' => wfMsgHtml( "prevn", $this->mLimit
),
407 'next' => wfMsgHtml( 'nextn', $this->mLimit
),
408 'first' => wfMsgHtml('histlast'),
409 'last' => wfMsgHtml( 'histfirst' )
412 $pagingLinks = $this->getPagingLinks( $linkTexts );
413 $limitLinks = $this->getLimitLinks();
414 $limits = implode( ' | ', $limitLinks );
416 $this->mNavigationBar
= "({$pagingLinks['first']} | {$pagingLinks['last']}) " . wfMsgHtml("viewprevnext", $pagingLinks['prev'], $pagingLinks['next'], $limits);
417 return $this->mNavigationBar
;
422 * Table-based display with a user-selectable sort order
424 abstract class TablePager
extends IndexPager
{
428 function __construct() {
430 $this->mSort
= $wgRequest->getText( 'sort' );
431 if ( !array_key_exists( $this->mSort
, $this->getFieldNames() ) ) {
432 $this->mSort
= $this->getDefaultSort();
434 if ( $wgRequest->getBool( 'asc' ) ) {
435 $this->mDefaultDirection
= false;
436 } elseif ( $wgRequest->getBool( 'desc' ) ) {
437 $this->mDefaultDirection
= true;
438 } /* Else leave it at whatever the class default is */
440 parent
::__construct();
443 function getStartBody() {
445 $tableClass = htmlspecialchars( $this->getTableClass() );
446 $sortClass = htmlspecialchars( $this->getSortHeaderClass() );
448 $s = "<table border='1' class=\"$tableClass\"><thead><tr>\n";
449 $fields = $this->getFieldNames();
450 foreach ( $fields as $field => $name ) {
451 if ( strval( $name ) == '' ) {
452 $s .= "<th> </th>\n";
453 } elseif ( $this->isFieldSortable( $field ) ) {
454 $query = array( 'sort' => $field, 'limit' => $this->mLimit
);
455 if ( $field == $this->mSort
) {
456 # This is the sorted column
457 # Prepare a link that goes in the other sort order
458 if ( $this->mDefaultDirection
) {
460 $image = 'Arr_u.png';
463 $alt = htmlspecialchars( wfMsg( 'descending_abbrev' ) );
466 $image = 'Arr_d.png';
468 $query['desc'] = '1';
469 $alt = htmlspecialchars( wfMsg( 'ascending_abbrev' ) );
471 $image = htmlspecialchars( "$wgStylePath/common/images/$image" );
472 $link = $this->makeLink(
473 "<img width=\"12\" height=\"12\" alt=\"$alt\" src=\"$image\" />" .
474 htmlspecialchars( $name ), $query );
475 $s .= "<th class=\"$sortClass\">$link</th>\n";
477 $s .= '<th>' . $this->makeLink( htmlspecialchars( $name ), $query ) . "</th>\n";
480 $s .= '<th>' . htmlspecialchars( $name ) . "</th>\n";
483 $s .= "</tr></thead><tbody>\n";
487 function getEndBody() {
488 return '</tbody></table>';
491 function getEmptyBody() {
492 $colspan = count( $this->getFieldNames() );
493 $msgEmpty = wfMsgHtml( 'table_pager_empty' );
494 return "<tr><td colspan=\"$colspan\">$msgEmpty</td></tr>\n";
497 function formatRow( $row ) {
499 $fieldNames = $this->getFieldNames();
500 $this->mCurrentRow
= $row; # In case formatValue needs to know
501 foreach ( $fieldNames as $field => $name ) {
502 $value = isset( $row->$field ) ?
$row->$field : null;
503 $formatted = strval( $this->formatValue( $field, $value ) );
504 if ( $formatted == '' ) {
505 $formatted = ' ';
507 $s .= "<td>$formatted</td>\n";
513 function getIndexField() {
517 function getTableClass() {
521 function getNavClass() {
522 return 'TablePager_nav';
525 function getSortHeaderClass() {
526 return 'TablePager_sort';
530 * A navigation bar with images
532 function getNavigationBar() {
533 global $wgStylePath, $wgContLang;
534 $path = "$wgStylePath/common/images";
536 'first' => 'table_pager_first',
537 'prev' => 'table_pager_prev',
538 'next' => 'table_pager_next',
539 'last' => 'table_pager_last',
542 'first' => $wgContLang->isRTL() ?
'arrow_last_25.png' : 'arrow_first_25.png',
543 'prev' => $wgContLang->isRTL() ?
'arrow_right_25.png' : 'arrow_left_25.png',
544 'next' => $wgContLang->isRTL() ?
'arrow_left_25.png' : 'arrow_right_25.png',
545 'last' => $wgContLang->isRTL() ?
'arrow_first_25.png' : 'arrow_last_25.png',
547 $disabledImages = array(
548 'first' => $wgContLang->isRTL() ?
'arrow_disabled_last_25.png' : 'arrow_disabled_first_25.png',
549 'prev' => $wgContLang->isRTL() ?
'arrow_disabled_right_25.png' : 'arrow_disabled_left_25.png',
550 'next' => $wgContLang->isRTL() ?
'arrow_disabled_left_25.png' : 'arrow_disabled_right_25.png',
551 'last' => $wgContLang->isRTL() ?
'arrow_disabled_first_25.png' : 'arrow_disabled_last_25.png',
554 $linkTexts = array();
555 $disabledTexts = array();
556 foreach ( $labels as $type => $label ) {
557 $msgLabel = wfMsgHtml( $label );
558 $linkTexts[$type] = "<img src=\"$path/{$images[$type]}\" alt=\"$msgLabel\"/><br/>$msgLabel";
559 $disabledTexts[$type] = "<img src=\"$path/{$disabledImages[$type]}\" alt=\"$msgLabel\"/><br/>$msgLabel";
561 $links = $this->getPagingLinks( $linkTexts, $disabledTexts );
563 $navClass = htmlspecialchars( $this->getNavClass() );
564 $s = "<table class=\"$navClass\" align=\"center\" cellpadding=\"3\"><tr>";
565 $cellAttrs = 'valign="top" align="center" width="' . 100 / count( $links ) . '%"';
566 foreach ( $labels as $type => $label ) {
567 $s .= "<td $cellAttrs>{$links[$type]}</td>\n";
569 $s .= '</tr></table>';
574 * Get a <select> element which has options for each of the allowed limits
576 function getLimitSelect() {
578 $s = "<select name=\"limit\">";
579 foreach ( $this->mLimitsShown
as $limit ) {
580 $selected = $limit == $this->mLimit ?
'selected="selected"' : '';
581 $formattedLimit = $wgLang->formatNum( $limit );
582 $s .= "<option value=\"$limit\" $selected>$formattedLimit</option>\n";
589 * Get <input type="hidden"> elements for use in a method="get" form.
590 * Resubmits all defined elements of the $_GET array, except for a
591 * blacklist, passed in the $blacklist parameter.
593 function getHiddenFields( $blacklist = array() ) {
594 $blacklist = (array)$blacklist;
596 foreach ( $blacklist as $name ) {
597 unset( $query[$name] );
600 foreach ( $query as $name => $value ) {
601 $encName = htmlspecialchars( $name );
602 $encValue = htmlspecialchars( $value );
603 $s .= "<input type=\"hidden\" name=\"$encName\" value=\"$encValue\"/>\n";
609 * Get a form containing a limit selection dropdown
611 function getLimitForm() {
612 # Make the select with some explanatory text
613 $url = $this->getTitle()->escapeLocalURL();
614 $msgSubmit = wfMsgHtml( 'table_pager_limit_submit' );
616 "<form method=\"get\" action=\"$url\">" .
617 wfMsgHtml( 'table_pager_limit', $this->getLimitSelect() ) .
618 "\n<input type=\"submit\" value=\"$msgSubmit\"/>\n" .
619 $this->getHiddenFields( 'limit' ) .
624 * Return true if the named field should be sortable by the UI, false otherwise
625 * @param string $field
627 abstract function isFieldSortable( $field );
630 * Format a table cell. The return value should be HTML, but use an empty string
631 * not for empty cells. Do not include the <td> and </td>.
633 * @param string $name The database field name
634 * @param string $value The value retrieved from the database
636 * The current result row is available as $this->mCurrentRow, in case you need
639 abstract function formatValue( $name, $value );
642 * The database field name used as a default sort order
644 abstract function getDefaultSort();
647 * An array mapping database field names to a textual description of the field
648 * name, for use in the table header. The description should be plain text, it
649 * will be HTML-escaped later.
651 abstract function getFieldNames();