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authorPierre Schmitz <pierre@archlinux.de>2006-10-11 20:21:25 +0000
committerPierre Schmitz <pierre@archlinux.de>2006-10-11 20:21:25 +0000
commitd81f562b712f2387fa02290bf2ca86392ab356f2 (patch)
treed666cdefbe6ac320827a2c6cb473581b46e22c4c /includes/Pager.php
parent183851b06bd6c52f3cae5375f433da720d410447 (diff)
Aktualisierung auf Version 1.8.1
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+<?php
+
+/**
+ * Basic pager interface.
+ */
+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.
+ */
+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;
+ $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' );
+ $this->mLimit = $this->mRequest->getInt( 'limit', $this->mDefaultLimit );
+ if ( $this->mLimit <= 0 || $this->mLimit > 50000 ) {
+ $this->mLimit = $this->mDefaultLimit;
+ }
+ $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;
+
+ 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, $ascending ) {
+ $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 ( $ascending ) {
+ $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, $res );
+ }
+
+ /**
+ * Get the formatted result list. Calls getStartBody(), formatRow() and
+ * getEndBody(), concatenates the results and returns them.
+ */
+ function getBody() {
+ if ( !$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 compact( 'prev', 'next', 'first', '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 a formatted navigation bar
+ */
+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
+ */
+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>&nbsp;</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>';
+ }
+
+ 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 = '&nbsp;';
+ }
+ $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>";
+ $cellAttrs = 'valign="top" align="center" width="' . 100 / count( $links ) . '%"';
+ foreach ( $labels as $type => $label ) {
+ $s .= "<td $cellAttrs>{$links[$type]}</td>\n";
+ }
+ $s .= '</tr></table>';
+ 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 &nbsp; for empty cells. Do not include the <td> and </td>.
+ *
+ * @param string $name The database field name
+ * @param string $value The value retrieved from the database
+ *
+ * The current result row is available as $this->mCurrentRow, in case you need
+ * more context.
+ */
+ 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();
+}
+?>