<?php
/**
* Basic pager interface.
* @addtogroup Pager
*/
interface Pager {
function getNavigationBar();
function getBody();
}
/**
* IndexPager is an efficient pager which uses a (roughly unique) index in the
* data set to implement paging, rather than a "LIMIT offset,limit" clause.
* In MySQL, such a limit/offset clause requires counting through the
* specified number of offset rows to find the desired data, which can be
* expensive for large offsets.
*
* ReverseChronologicalPager is a child class of the abstract IndexPager, and
* contains some formatting and display code which is specific to the use of
* timestamps as indexes. Here is a synopsis of its operation:
*
* * The query is specified by the offset, limit and direction (dir)
* parameters, in addition to any subclass-specific parameters.
* * The offset is the non-inclusive start of the DB query. A row with an
* index value equal to the offset will never be shown.
* * The query may either be done backwards, where the rows are returned by
* the database in the opposite order to which they are displayed to the
* user, or forwards. This is specified by the "dir" parameter, dir=prev
* means backwards, anything else means forwards. The offset value
* specifies the start of the database result set, which may be either
* the start or end of the displayed data set. This allows "previous"
* links to be implemented without knowledge of the index value at the
* start of the previous page.
* * An additional row beyond the user-specified limit is always requested.
* This allows us to tell whether we should display a "next" link in the
* case of forwards mode, or a "previous" link in the case of backwards
* mode. Determining whether to display the other link (the one for the
* page before the start of the database result set) can be done
* heuristically by examining the offset.
*
* * An empty offset indicates that the offset condition should be omitted
* from the query. This naturally produces either the first page or the
* last page depending on the dir parameter.
*
* Subclassing the pager to implement concrete functionality should be fairly
* simple, please see the examples in PageHistory.php and
* SpecialIpblocklist.php. You just need to override formatRow(),
* getQueryInfo() and getIndexField(). Don't forget to call the parent
* constructor if you override it.
*
* @addtogroup Pager
*/
abstract class IndexPager implements Pager {
public $mRequest;
public $mLimitsShown = array( 20, 50, 100, 250, 500 );
public $mDefaultLimit = 50;
public $mOffset, $mLimit;
public $mQueryDone = false;
public $mDb;
public $mPastTheEndRow;
protected $mIndexField;
/**
* Default query direction. false for ascending, true for descending
*/
public $mDefaultDirection = false;
/**
* Result object for the query. Warning: seek before use.
*/
public $mResult;
function __construct() {
global $wgRequest, $wgUser;
$this->mRequest = $wgRequest;
# NB: the offset is quoted, not validated. It is treated as an
# arbitrary string to support the widest variety of index types. Be
# careful outputting it into HTML!
$this->mOffset = $this->mRequest->getText( 'offset' );
# Use consistent behavior for the limit options
$this->mDefaultLimit = intval( $wgUser->getOption( 'rclimit' ) );
list( $this->mLimit, /* $offset */ ) = $this->mRequest->getLimitOffset();
$this->mIsBackwards = ( $this->mRequest->getVal( 'dir' ) == 'prev' );
$this->mIndexField = $this->getIndexField();
$this->mDb = wfGetDB( DB_SLAVE );
}
/**
* Do the query, using information from the object context. This function
* has been kept minimal to make it overridable if necessary, to allow for
* result sets formed from multiple DB queries.
*/
function doQuery() {
# Use the child class name for profiling
$fname = __METHOD__ . ' (' . get_class( $this ) . ')';
wfProfileIn( $fname );
$descending = ( $this->mIsBackwards == $this->mDefaultDirection );
# Plus an extra row so that we can tell the "next" link should be shown
$queryLimit = $this->mLimit + 1;
$this->mResult = $this->reallyDoQuery( $this->mOffset, $queryLimit, $descending );
$this->extractResultInfo( $this->mOffset, $queryLimit, $this->mResult );
$this->mQueryDone = true;
$this->preprocessResults( $this->mResult );
$this->mResult->rewind(); // Paranoia
wfProfileOut( $fname );
}
/**
* Extract some useful data from the result object for use by
* the navigation bar, put it into $this
*/
function extractResultInfo( $offset, $limit, ResultWrapper $res ) {
$numRows = $res->numRows();
if ( $numRows ) {
$row = $res->fetchRow();
$firstIndex = $row[$this->mIndexField];
# Discard the extra result row if there is one
if ( $numRows > $this->mLimit && $numRows > 1 ) {
$res->seek( $numRows - 1 );
$this->mPastTheEndRow = $res->fetchObject();
$indexField = $this->mIndexField;
$this->mPastTheEndIndex = $this->mPastTheEndRow->$indexField;
$res->seek( $numRows - 2 );
$row = $res->fetchRow();
$lastIndex = $row[$this->mIndexField];
} else {
$this->mPastTheEndRow = null;
# Setting indexes to an empty string means that they will be
# omitted if they would otherwise appear in URLs. It just so
# happens that this is the right thing to do in the standard
# UI, in all the relevant cases.
$this->mPastTheEndIndex = '';
$res->seek( $numRows - 1 );
$row = $res->fetchRow();
$lastIndex = $row[$this->mIndexField];
}
} else {
$firstIndex = '';
$lastIndex = '';
$this->mPastTheEndRow = null;
$this->mPastTheEndIndex = '';
}
if ( $this->mIsBackwards ) {
$this->mIsFirst = ( $numRows < $limit );
$this->mIsLast = ( $offset == '' );
$this->mLastShown = $firstIndex;
$this->mFirstShown = $lastIndex;
} else {
$this->mIsFirst = ( $offset == '' );
$this->mIsLast = ( $numRows < $limit );
$this->mLastShown = $lastIndex;
$this->mFirstShown = $firstIndex;
}
}
/**
* Do a query with specified parameters, rather than using the object
* context
*
* @param string $offset Index offset, inclusive
* @param integer $limit Exact query limit
* @param boolean $descending Query direction, false for ascending, true for descending
* @return ResultWrapper
*/
function reallyDoQuery( $offset, $limit, $descending ) {
$fname = __METHOD__ . ' (' . get_class( $this ) . ')';
$info = $this->getQueryInfo();
$tables = $info['tables'];
$fields = $info['fields'];
$conds = isset( $info['conds'] ) ? $info['conds'] : array();
$options = isset( $info['options'] ) ? $info['options'] : array();
if ( $descending ) {
$options['ORDER BY'] = $this->mIndexField;
$operator = '>';
} else {
$options['ORDER BY'] = $this->mIndexField . ' DESC';
$operator = '<';
}
if ( $offset != '' ) {
$conds[] = $this->mIndexField . $operator . $this->mDb->addQuotes( $offset );
}
$options['LIMIT'] = intval( $limit );
$res = $this->mDb->select( $tables, $fields, $conds, $fname, $options );
return new ResultWrapper( $this->mDb, $res );
}
/**
* Pre-process results; useful for performing batch existence checks, etc.
*
* @param ResultWrapper $result Result wrapper
*/
protected function preprocessResults( $result ) {}
/**
* Get the formatted result list. Calls getStartBody(), formatRow() and
* getEndBody(), concatenates the results and returns them.
*/
function getBody() {
if ( !$this->mQueryDone ) {
$this->doQuery();
}
# Don't use any extra rows returned by the query
$numRows = min( $this->mResult->numRows(), $this->mLimit );
$s = $this->getStartBody();
if ( $numRows ) {
if ( $this->mIsBackwards ) {
for ( $i = $numRows - 1; $i >= 0; $i-- ) {
$this->mResult->seek( $i );
$row = $this->mResult->fetchObject();
$s .= $this->formatRow( $row );
}
} else {
$this->mResult->seek( 0 );
for ( $i = 0; $i < $numRows; $i++ ) {
$row = $this->mResult->fetchObject();
$s .= $this->formatRow( $row );
}
}
} else {
$s .= $this->getEmptyBody();
}
$s .= $this->getEndBody();
return $s;
}
/**
* Make a self-link
*/
function makeLink($text, $query = NULL) {
if ( $query === null ) {
return $text;
} else {
return $this->getSkin()->makeKnownLinkObj( $this->getTitle(), $text,
wfArrayToCGI( $query, $this->getDefaultQuery() ) );
}
}
/**
* Hook into getBody(), allows text to be inserted at the start. This
* will be called even if there are no rows in the result set.
*/
function getStartBody() {
return '';
}
/**
* Hook into getBody() for the end of the list
*/
function getEndBody() {
return '';
}
/**
* Hook into getBody(), for the bit between the start and the
* end when there are no rows
*/
function getEmptyBody() {
return '';
}
/**
* Title used for self-links. Override this if you want to be able to
* use a title other than $wgTitle
*/
function getTitle() {
return $GLOBALS['wgTitle'];
}
/**
* Get the current skin. This can be overridden if necessary.
*/
function getSkin() {
if ( !isset( $this->mSkin ) ) {
global $wgUser;
$this->mSkin = $wgUser->getSkin();
}
return $this->mSkin;
}
/**
* Get an array of query parameters that should be put into self-links.
* By default, all parameters passed in the URL are used, except for a
* short blacklist.
*/
function getDefaultQuery() {
if ( !isset( $this->mDefaultQuery ) ) {
$this->mDefaultQuery = $_GET;
unset( $this->mDefaultQuery['title'] );
unset( $this->mDefaultQuery['dir'] );
unset( $this->mDefaultQuery['offset'] );
unset( $this->mDefaultQuery['limit'] );
}
return $this->mDefaultQuery;
}
/**
* Get the number of rows in the result set
*/
function getNumRows() {
if ( !$this->mQueryDone ) {
$this->doQuery();
}
return $this->mResult->numRows();
}
/**
* Get a query array for the prev, next, first and last links.
*/
function getPagingQueries() {
if ( !$this->mQueryDone ) {
$this->doQuery();
}
# Don't announce the limit everywhere if it's the default
$urlLimit = $this->mLimit == $this->mDefaultLimit ? '' : $this->mLimit;
if ( $this->mIsFirst ) {
$prev = false;
$first = false;
} else {
$prev = array( 'dir' => 'prev', 'offset' => $this->mFirstShown, 'limit' => $urlLimit );
$first = array( 'limit' => $urlLimit );
}
if ( $this->mIsLast ) {
$next = false;
$last = false;
} else {
$next = array( 'offset' => $this->mLastShown, 'limit' => $urlLimit );
$last = array( 'dir' => 'prev', 'limit' => $urlLimit );
}
return array( 'prev' => $prev, 'next' => $next, 'first' => $first, 'last' => $last );
}
/**
* Get paging links. If a link is disabled, the item from $disabledTexts
* will be used. If there is no such item, the unlinked text from
* $linkTexts will be used. Both $linkTexts and $disabledTexts are arrays
* of HTML.
*/
function getPagingLinks( $linkTexts, $disabledTexts = array() ) {
$queries = $this->getPagingQueries();
$links = array();
foreach ( $queries as $type => $query ) {
if ( $query !== false ) {
$links[$type] = $this->makeLink( $linkTexts[$type], $queries[$type] );
} elseif ( isset( $disabledTexts[$type] ) ) {
$links[$type] = $disabledTexts[$type];
} else {
$links[$type] = $linkTexts[$type];
}
}
return $links;
}
function getLimitLinks() {
global $wgLang;
$links = array();
if ( $this->mIsBackwards ) {
$offset = $this->mPastTheEndIndex;
} else {
$offset = $this->mOffset;
}
foreach ( $this->mLimitsShown as $limit ) {
$links[] = $this->makeLink( $wgLang->formatNum( $limit ),
array( 'offset' => $offset, 'limit' => $limit ) );
}
return $links;
}
/**
* Abstract formatting function. This should return an HTML string
* representing the result row $row. Rows will be concatenated and
* returned by getBody()
*/
abstract function formatRow( $row );
/**
* This function should be overridden to provide all parameters
* needed for the main paged query. It returns an associative
* array with the following elements:
* tables => Table(s) for passing to Database::select()
* fields => Field(s) for passing to Database::select(), may be *
* conds => WHERE conditions
* options => option array
*/
abstract function getQueryInfo();
/**
* This function should be overridden to return the name of the
* index field.
*/
abstract function getIndexField();
}
/**
* IndexPager with an alphabetic list and a formatted navigation bar
* @addtogroup Pager
*/
abstract class AlphabeticPager extends IndexPager {
public $mDefaultDirection = false;
function __construct() {
parent::__construct();
}
/**
* Shamelessly stolen bits from ReverseChronologicalPager, d
* didn't want to do class magic as may be still revamped
*/
function getNavigationBar() {
global $wgLang;
$linkTexts = array(
'prev' => wfMsgHtml( "prevn", $this->mLimit ),
'next' => wfMsgHtml( 'nextn', $this->mLimit ),
'first' => wfMsgHtml('page_first'), /* Introduced the message */
'last' => wfMsgHtml( 'page_last' ) /* Introduced the message */
);
$pagingLinks = $this->getPagingLinks( $linkTexts );
$limitLinks = $this->getLimitLinks();
$limits = implode( ' | ', $limitLinks );
$this->mNavigationBar = "({$pagingLinks['first']} | {$pagingLinks['last']}) " . wfMsgHtml("viewprevnext", $pagingLinks['prev'], $pagingLinks['next'], $limits);
return $this->mNavigationBar;
}
}
/**
* IndexPager with a formatted navigation bar
* @addtogroup Pager
*/
abstract class ReverseChronologicalPager extends IndexPager {
public $mDefaultDirection = true;
function __construct() {
parent::__construct();
}
function getNavigationBar() {
global $wgLang;
if ( isset( $this->mNavigationBar ) ) {
return $this->mNavigationBar;
}
$linkTexts = array(
'prev' => wfMsgHtml( "prevn", $this->mLimit ),
'next' => wfMsgHtml( 'nextn', $this->mLimit ),
'first' => wfMsgHtml('histlast'),
'last' => wfMsgHtml( 'histfirst' )
);
$pagingLinks = $this->getPagingLinks( $linkTexts );
$limitLinks = $this->getLimitLinks();
$limits = implode( ' | ', $limitLinks );
$this->mNavigationBar = "({$pagingLinks['first']} | {$pagingLinks['last']}) " .
wfMsgHtml("viewprevnext", $pagingLinks['prev'], $pagingLinks['next'], $limits);
return $this->mNavigationBar;
}
}
/**
* Table-based display with a user-selectable sort order
* @addtogroup Pager
*/
abstract class TablePager extends IndexPager {
var $mSort;
var $mCurrentRow;
function __construct() {
global $wgRequest;
$this->mSort = $wgRequest->getText( 'sort' );
if ( !array_key_exists( $this->mSort, $this->getFieldNames() ) ) {
$this->mSort = $this->getDefaultSort();
}
if ( $wgRequest->getBool( 'asc' ) ) {
$this->mDefaultDirection = false;
} elseif ( $wgRequest->getBool( 'desc' ) ) {
$this->mDefaultDirection = true;
} /* Else leave it at whatever the class default is */
parent::__construct();
}
function getStartBody() {
global $wgStylePath;
$tableClass = htmlspecialchars( $this->getTableClass() );
$sortClass = htmlspecialchars( $this->getSortHeaderClass() );
$s = "<table border='1' class=\"$tableClass\"><thead><tr>\n";
$fields = $this->getFieldNames();
# Make table header
foreach ( $fields as $field => $name ) {
if ( strval( $name ) == '' ) {
$s .= "<th> </th>\n";
} elseif ( $this->isFieldSortable( $field ) ) {
$query = array( 'sort' => $field, 'limit' => $this->mLimit );
if ( $field == $this->mSort ) {
# This is the sorted column
# Prepare a link that goes in the other sort order
if ( $this->mDefaultDirection ) {
# Descending
$image = 'Arr_u.png';
$query['asc'] = '1';
$query['desc'] = '';
$alt = htmlspecialchars( wfMsg( 'descending_abbrev' ) );
} else {
# Ascending
$image = 'Arr_d.png';
$query['asc'] = '';
$query['desc'] = '1';
$alt = htmlspecialchars( wfMsg( 'ascending_abbrev' ) );
}
$image = htmlspecialchars( "$wgStylePath/common/images/$image" );
$link = $this->makeLink(
"<img width=\"12\" height=\"12\" alt=\"$alt\" src=\"$image\" />" .
htmlspecialchars( $name ), $query );
$s .= "<th class=\"$sortClass\">$link</th>\n";
} else {
$s .= '<th>' . $this->makeLink( htmlspecialchars( $name ), $query ) . "</th>\n";
}
} else {
$s .= '<th>' . htmlspecialchars( $name ) . "</th>\n";
}
}
$s .= "</tr></thead><tbody>\n";
return $s;
}
function getEndBody() {
return "</tbody></table>\n";
}
function getEmptyBody() {
$colspan = count( $this->getFieldNames() );
$msgEmpty = wfMsgHtml( 'table_pager_empty' );
return "<tr><td colspan=\"$colspan\">$msgEmpty</td></tr>\n";
}
function formatRow( $row ) {
$s = "<tr>\n";
$fieldNames = $this->getFieldNames();
$this->mCurrentRow = $row; # In case formatValue needs to know
foreach ( $fieldNames as $field => $name ) {
$value = isset( $row->$field ) ? $row->$field : null;
$formatted = strval( $this->formatValue( $field, $value ) );
if ( $formatted == '' ) {
$formatted = ' ';
}
$class = 'TablePager_col_' . htmlspecialchars( $field );
$s .= "<td class=\"$class\">$formatted</td>\n";
}
$s .= "</tr>\n";
return $s;
}
function getIndexField() {
return $this->mSort;
}
function getTableClass() {
return 'TablePager';
}
function getNavClass() {
return 'TablePager_nav';
}
function getSortHeaderClass() {
return 'TablePager_sort';
}
/**
* A navigation bar with images
*/
function getNavigationBar() {
global $wgStylePath, $wgContLang;
$path = "$wgStylePath/common/images";
$labels = array(
'first' => 'table_pager_first',
'prev' => 'table_pager_prev',
'next' => 'table_pager_next',
'last' => 'table_pager_last',
);
$images = array(
'first' => $wgContLang->isRTL() ? 'arrow_last_25.png' : 'arrow_first_25.png',
'prev' => $wgContLang->isRTL() ? 'arrow_right_25.png' : 'arrow_left_25.png',
'next' => $wgContLang->isRTL() ? 'arrow_left_25.png' : 'arrow_right_25.png',
'last' => $wgContLang->isRTL() ? 'arrow_first_25.png' : 'arrow_last_25.png',
);
$disabledImages = array(
'first' => $wgContLang->isRTL() ? 'arrow_disabled_last_25.png' : 'arrow_disabled_first_25.png',
'prev' => $wgContLang->isRTL() ? 'arrow_disabled_right_25.png' : 'arrow_disabled_left_25.png',
'next' => $wgContLang->isRTL() ? 'arrow_disabled_left_25.png' : 'arrow_disabled_right_25.png',
'last' => $wgContLang->isRTL() ? 'arrow_disabled_first_25.png' : 'arrow_disabled_last_25.png',
);
$linkTexts = array();
$disabledTexts = array();
foreach ( $labels as $type => $label ) {
$msgLabel = wfMsgHtml( $label );
$linkTexts[$type] = "<img src=\"$path/{$images[$type]}\" alt=\"$msgLabel\"/><br/>$msgLabel";
$disabledTexts[$type] = "<img src=\"$path/{$disabledImages[$type]}\" alt=\"$msgLabel\"/><br/>$msgLabel";
}
$links = $this->getPagingLinks( $linkTexts, $disabledTexts );
$navClass = htmlspecialchars( $this->getNavClass() );
$s = "<table class=\"$navClass\" align=\"center\" cellpadding=\"3\"><tr>\n";
$cellAttrs = 'valign="top" align="center" width="' . 100 / count( $links ) . '%"';
foreach ( $labels as $type => $label ) {
$s .= "<td $cellAttrs>{$links[$type]}</td>\n";
}
$s .= "</tr></table>\n";
return $s;
}
/**
* Get a <select> element which has options for each of the allowed limits
*/
function getLimitSelect() {
global $wgLang;
$s = "<select name=\"limit\">";
foreach ( $this->mLimitsShown as $limit ) {
$selected = $limit == $this->mLimit ? 'selected="selected"' : '';
$formattedLimit = $wgLang->formatNum( $limit );
$s .= "<option value=\"$limit\" $selected>$formattedLimit</option>\n";
}
$s .= "</select>";
return $s;
}
/**
* Get <input type="hidden"> elements for use in a method="get" form.
* Resubmits all defined elements of the $_GET array, except for a
* blacklist, passed in the $blacklist parameter.
*/
function getHiddenFields( $blacklist = array() ) {
$blacklist = (array)$blacklist;
$query = $_GET;
foreach ( $blacklist as $name ) {
unset( $query[$name] );
}
$s = '';
foreach ( $query as $name => $value ) {
$encName = htmlspecialchars( $name );
$encValue = htmlspecialchars( $value );
$s .= "<input type=\"hidden\" name=\"$encName\" value=\"$encValue\"/>\n";
}
return $s;
}
/**
* Get a form containing a limit selection dropdown
*/
function getLimitForm() {
# Make the select with some explanatory text
$url = $this->getTitle()->escapeLocalURL();
$msgSubmit = wfMsgHtml( 'table_pager_limit_submit' );
return
"<form method=\"get\" action=\"$url\">" .
wfMsgHtml( 'table_pager_limit', $this->getLimitSelect() ) .
"\n<input type=\"submit\" value=\"$msgSubmit\"/>\n" .
$this->getHiddenFields( 'limit' ) .
"</form>\n";
}
/**
* Return true if the named field should be sortable by the UI, false
* otherwise
*
* @param string $field
*/
abstract function isFieldSortable( $field );
/**
* Format a table cell. The return value should be HTML, but use an empty
* string not for empty cells. Do not include the <td> and </td>.
*
* The current result row is available as $this->mCurrentRow, in case you
* need more context.
*
* @param string $name The database field name
* @param string $value The value retrieved from the database
*/
abstract function formatValue( $name, $value );
/**
* The database field name used as a default sort order
*/
abstract function getDefaultSort();
/**
* An array mapping database field names to a textual description of the
* field name, for use in the table header. The description should be plain
* text, it will be HTML-escaped later.
*/
abstract function getFieldNames();
}
