Move remaining LoadBalancer classes to Rdbms

[mediawiki.git] / includes / pager / TablePager.php

<?php
/**
 * Efficient paging for SQL queries.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @ingroup Pager
 */

/**
 * Table-based display with a user-selectable sort order
 * @ingroup Pager
 */
abstract class TablePager extends IndexPager {
        protected $mSort;

        protected $mCurrentRow;

        public function __construct( IContextSource $context = null ) {
                if ( $context ) {
                        $this->setContext( $context );
                }

                $this->mSort = $this->getRequest()->getText( 'sort' );
                if ( !array_key_exists( $this->mSort, $this->getFieldNames() )
                        || !$this->isFieldSortable( $this->mSort )
                ) {
                        $this->mSort = $this->getDefaultSort();
                }
                if ( $this->getRequest()->getBool( 'asc' ) ) {
                        $this->mDefaultDirection = IndexPager::DIR_ASCENDING;
                } elseif ( $this->getRequest()->getBool( 'desc' ) ) {
                        $this->mDefaultDirection = IndexPager::DIR_DESCENDING;
                } /* Else leave it at whatever the class default is */

                parent::__construct();
        }

        /**
         * Get the formatted result list. Calls getStartBody(), formatRow() and getEndBody(), concatenates
         * the results and returns them.
         *
         * Also adds the required styles to our OutputPage object (this means that if context wasn't
         * passed to constructor or otherwise set up, you will get a pager with missing styles).
         *
         * This method has been made 'final' in 1.24. There's no reason to override it, and if there exist
         * any subclasses that do, the style loading hack is probably broken in them. Let's fail fast
         * rather than mysteriously render things wrong.
         *
         * @deprecated since 1.24, use getBodyOutput() or getFullOutput() instead
         * @return string
         */
        final public function getBody() {
                $this->getOutput()->addModuleStyles( $this->getModuleStyles() );
                return parent::getBody();
        }

        /**
         * Get the formatted result list.
         *
         * Calls getBody() and getModuleStyles() and builds a ParserOutput object. (This is a bit hacky
         * but works well.)
         *
         * @since 1.24
         * @return ParserOutput
         */
        public function getBodyOutput() {
                $body = parent::getBody();

                $pout = new ParserOutput;
                $pout->setText( $body );
                $pout->addModuleStyles( $this->getModuleStyles() );
                return $pout;
        }

        /**
         * Get the formatted result list, with navigation bars.
         *
         * Calls getBody(), getNavigationBar() and getModuleStyles() and
         * builds a ParserOutput object. (This is a bit hacky but works well.)
         *
         * @since 1.24
         * @return ParserOutput
         */
        public function getFullOutput() {
                $navigation = $this->getNavigationBar();
                $body = parent::getBody();

                $pout = new ParserOutput;
                $pout->setText( $navigation . $body . $navigation );
                $pout->addModuleStyles( $this->getModuleStyles() );
                return $pout;
        }

        /**
         * @protected
         * @return string
         */
        function getStartBody() {
                $sortClass = $this->getSortHeaderClass();

                $s = '';
                $fields = $this->getFieldNames();

                // Make table header
                foreach ( $fields as $field => $name ) {
                        if ( strval( $name ) == '' ) {
                                $s .= Html::rawElement( 'th', [], '&#160;' ) . "\n";
                        } elseif ( $this->isFieldSortable( $field ) ) {
                                $query = [ 'sort' => $field, 'limit' => $this->mLimit ];
                                $linkType = null;
                                $class = null;

                                if ( $this->mSort == $field ) {
                                        // The table is sorted by this field already, make a link to sort in the other direction
                                        // We don't actually know in which direction other fields will be sorted by default…
                                        if ( $this->mDefaultDirection == IndexPager::DIR_DESCENDING ) {
                                                $linkType = 'asc';
                                                $class = "$sortClass TablePager_sort-descending";
                                                $query['asc'] = '1';
                                                $query['desc'] = '';
                                        } else {
                                                $linkType = 'desc';
                                                $class = "$sortClass TablePager_sort-ascending";
                                                $query['asc'] = '';
                                                $query['desc'] = '1';
                                        }
                                }

                                $link = $this->makeLink( htmlspecialchars( $name ), $query, $linkType );
                                $s .= Html::rawElement( 'th', [ 'class' => $class ], $link ) . "\n";
                        } else {
                                $s .= Html::element( 'th', [], $name ) . "\n";
                        }
                }

                $tableClass = $this->getTableClass();
                $ret = Html::openElement( 'table', [
                        'class' => "mw-datatable $tableClass" ]
                );
                $ret .= Html::rawElement( 'thead', [], Html::rawElement( 'tr', [], "\n" . $s . "\n" ) );
                $ret .= Html::openElement( 'tbody' ) . "\n";

                return $ret;
        }

        /**
         * @protected
         * @return string
         */
        function getEndBody() {
                return "</tbody></table>\n";
        }

        /**
         * @protected
         * @return string
         */
        function getEmptyBody() {
                $colspan = count( $this->getFieldNames() );
                $msgEmpty = $this->msg( 'table_pager_empty' )->text();
                return Html::rawElement( 'tr', [],
                        Html::element( 'td', [ 'colspan' => $colspan ], $msgEmpty ) );
        }

        /**
         * @protected
         * @param stdClass $row
         * @return string HTML
         */
        function formatRow( $row ) {
                $this->mCurrentRow = $row; // In case formatValue etc need to know
                $s = Html::openElement( 'tr', $this->getRowAttrs( $row ) ) . "\n";
                $fieldNames = $this->getFieldNames();

                foreach ( $fieldNames as $field => $name ) {
                        $value = isset( $row->$field ) ? $row->$field : null;
                        $formatted = strval( $this->formatValue( $field, $value ) );

                        if ( $formatted == '' ) {
                                $formatted = '&#160;';
                        }

                        $s .= Html::rawElement( 'td', $this->getCellAttrs( $field, $value ), $formatted ) . "\n";
                }

                $s .= Html::closeElement( 'tr' ) . "\n";

                return $s;
        }

        /**
         * Get a class name to be applied to the given row.
         *
         * @protected
         *
         * @param object $row The database result row
         * @return string
         */
        function getRowClass( $row ) {
                return '';
        }

        /**
         * Get attributes to be applied to the given row.
         *
         * @protected
         *
         * @param object $row The database result row
         * @return array Array of attribute => value
         */
        function getRowAttrs( $row ) {
                $class = $this->getRowClass( $row );
                if ( $class === '' ) {
                        // Return an empty array to avoid clutter in HTML like class=""
                        return [];
                } else {
                        return [ 'class' => $this->getRowClass( $row ) ];
                }
        }

        /**
         * @return stdClass
         */
        protected function getCurrentRow() {
                return $this->mCurrentRow;
        }

        /**
         * Get any extra attributes to be applied to the given cell. Don't
         * take this as an excuse to hardcode styles; use classes and
         * CSS instead.  Row context is available in $this->mCurrentRow
         *
         * @protected
         *
         * @param string $field The column
         * @param string $value The cell contents
         * @return array Array of attr => value
         */
        function getCellAttrs( $field, $value ) {
                return [ 'class' => 'TablePager_col_' . $field ];
        }

        /**
         * @protected
         * @return string
         */
        function getIndexField() {
                return $this->mSort;
        }

        /**
         * @return string
         */
        protected function getTableClass() {
                return 'TablePager';
        }

        /**
         * @return string
         */
        protected function getNavClass() {
                return 'TablePager_nav';
        }

        /**
         * @return string
         */
        protected function getSortHeaderClass() {
                return 'TablePager_sort';
        }

        /**
         * A navigation bar with images
         * @return string HTML
         */
        public function getNavigationBar() {
                if ( !$this->isNavigationBarShown() ) {
                        return '';
                }

                $labels = [
                        'first' => 'table_pager_first',
                        'prev' => 'table_pager_prev',
                        'next' => 'table_pager_next',
                        'last' => 'table_pager_last',
                ];

                $linkTexts = [];
                $disabledTexts = [];
                foreach ( $labels as $type => $label ) {
                        $msgLabel = $this->msg( $label )->escaped();
                        $linkTexts[$type] = "<div class='TablePager_nav-enabled'>$msgLabel</div>";
                        $disabledTexts[$type] = "<div class='TablePager_nav-disabled'>$msgLabel</div>";
                }
                $links = $this->getPagingLinks( $linkTexts, $disabledTexts );

                $s = Html::openElement( 'table', [ 'class' => $this->getNavClass() ] );
                $s .= Html::openElement( 'tr' ) . "\n";
                $width = 100 / count( $links ) . '%';
                foreach ( $labels as $type => $label ) {
                        // We want every cell to have the same width. We could use table-layout: fixed; in CSS,
                        // but it only works if we specify the width of a cell or the table and we don't want to.
                        // There is no better way. <https://www.w3.org/TR/CSS2/tables.html#fixed-table-layout>
                        $s .= Html::rawElement( 'td',
                                [ 'style' => "width: $width;", 'class' => "TablePager_nav-$type" ],
                                $links[$type] ) . "\n";
                }
                $s .= Html::closeElement( 'tr' ) . Html::closeElement( 'table' ) . "\n";
                return $s;
        }

        /**
         * ResourceLoader modules that must be loaded to provide correct styling for this pager
         * @since 1.24
         * @return string[]
         */
        public function getModuleStyles() {
                return [ 'mediawiki.pager.tablePager' ];
        }

        /**
         * Get a "<select>" element which has options for each of the allowed limits
         *
         * @param string[] $attribs Extra attributes to set
         * @return string HTML fragment
         */
        public function getLimitSelect( $attribs = [] ) {
                $select = new XmlSelect( 'limit', false, $this->mLimit );
                $select->addOptions( $this->getLimitSelectList() );
                foreach ( $attribs as $name => $value ) {
                        $select->setAttribute( $name, $value );
                }
                return $select->getHTML();
        }

        /**
         * Get a list of items to show in a "<select>" element of limits.
         * This can be passed directly to XmlSelect::addOptions().
         *
         * @since 1.22
         * @return array
         */
        public function getLimitSelectList() {
                # Add the current limit from the query string
                # to avoid that the limit is lost after clicking Go next time
                if ( !in_array( $this->mLimit, $this->mLimitsShown ) ) {
                        $this->mLimitsShown[] = $this->mLimit;
                        sort( $this->mLimitsShown );
                }
                $ret = [];
                foreach ( $this->mLimitsShown as $key => $value ) {
                        # The pair is either $index => $limit, in which case the $value
                        # will be numeric, or $limit => $text, in which case the $value
                        # will be a string.
                        if ( is_int( $value ) ) {
                                $limit = $value;
                                $text = $this->getLanguage()->formatNum( $limit );
                        } else {
                                $limit = $key;
                                $text = $value;
                        }
                        $ret[$text] = $limit;
                }
                return $ret;
        }

        /**
         * Get \<input type="hidden"\> elements for use in a method="get" form.
         * Resubmits all defined elements of the query string, except for a
         * blacklist, passed in the $blacklist parameter.
         *
         * @param array $blacklist Parameters from the request query which should not be resubmitted
         * @return string HTML fragment
         */
        function getHiddenFields( $blacklist = [] ) {
                $blacklist = (array)$blacklist;
                $query = $this->getRequest()->getQueryValues();
                foreach ( $blacklist as $name ) {
                        unset( $query[$name] );
                }
                $s = '';
                foreach ( $query as $name => $value ) {
                        $s .= Html::hidden( $name, $value ) . "\n";
                }
                return $s;
        }

        /**
         * Get a form containing a limit selection dropdown
         *
         * @return string HTML fragment
         */
        function getLimitForm() {
                return Html::rawElement(
                        'form',
                        [
                                'method' => 'get',
                                'action' => wfScript(),
                        ],
                        "\n" . $this->getLimitDropdown()
                ) . "\n";
        }

        /**
         * Gets a limit selection dropdown
         *
         * @return string
         */
        function getLimitDropdown() {
                # Make the select with some explanatory text
                $msgSubmit = $this->msg( 'table_pager_limit_submit' )->escaped();

                return $this->msg( 'table_pager_limit' )
                        ->rawParams( $this->getLimitSelect() )->escaped() .
                        "\n<input type=\"submit\" value=\"$msgSubmit\"/>\n" .
                        $this->getHiddenFields( [ 'limit' ] );
        }

        /**
         * 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 &#160; 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.
         *
         * @protected
         *
         * @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.
         *
         * @protected
         *
         * @return string
         */
        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.
         *
         * @return array
         */
        abstract function getFieldNames();
}