core/DataTable/Row/DataTableSummaryRow.php

<?php

/**
 * Matomo - free/libre analytics platform
 *
 * @link    https://matomo.org
 * @license https://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
 */

namespace Piwik\DataTable\Row;

use Piwik\DataTable;
use Piwik\DataTable\Row;

/**
 * A special row whose column values are the aggregate of the row's subtable.
 *
 * This class creates sets its own columns to the sum of each row in the row's subtable.
 *
 * Non-numeric columns are bypassed during summation and do not appear in this
 * rows columns.
 *
 * See {@link Piwik\DataTable\Row::sumRow()} for more information on the algorithm.
 *
 */
class DataTableSummaryRow extends Row
{
    /**
     * @param DataTable|null $subTable The subtable of this row. This parameter is mostly for
     *                                 convenience. If set, its rows will be summed to this one,
     *                                 but it will not be set as this row's subtable (so
     *                                 getSubtable() will return false).
     */
    public function __construct($subTable = null)
    {
        if (isset($subTable)) {
            $this->sumTable($subTable);
        }
    }

    /**
     * Re-sums the associated subtable's rows into this row's existing column values.
     */
    public function recalculate()
    {
        $subTable = $this->getSubtable();
        if ($subTable) {
            $this->sumTable($subTable);
        }
    }

    /**
     * Sums a tables row with this one.
     *
     * @param DataTable $table
     */
    private function sumTable($table)
    {
        $metadata = $table->getMetadata(DataTable::COLUMN_AGGREGATION_OPS_METADATA_NAME);
        $enableCopyMetadata = false;

        foreach ($table->getRowsWithoutSummaryRow() as $row) {
            $this->sumRow($row, $enableCopyMetadata, $metadata);
        }

        $summaryRow = $table->getRowFromId(DataTable::ID_SUMMARY_ROW);

        if ($summaryRow) {
            $this->sumRow($summaryRow, $enableCopyMetadata, $metadata);
        }
    }
}