C:/xampp/htdocs/moodle/lib/dtl/database_importer.php

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<?php

// This file is part of Moodle - http://moodle.org/
//
// Moodle 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 3 of the License, or
// (at your option) any later version.
//
// Moodle 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 Moodle.  If not, see <http://www.gnu.org/licenses/>.


defined('MOODLE_INTERNAL') || die();

class database_importer {
    protected $mdb;
    protected $manager;
    protected $schema;
    protected $check_schema;
    protected $transactionmode = 'allinone';
    protected $transaction;

    public function __construct(moodle_database $mdb, $check_schema=true) {
        $this->mdb          = $mdb;
        $this->manager      = $mdb->get_manager();
        $this->schema       = $this->manager->get_install_xml_schema();
        $this->check_schema = $check_schema;
    }

    public function set_transaction_mode($mode) {
        if (!in_array($mode, array('pertable', 'allinone', 'none'))) {
            throw new coding_exception('Unknown transaction mode', $mode);
        }
        $this->transactionmode = $mode;
    }

    public function begin_database_import($version, $timestamp) {
        global $CFG;

        if (!$this->mdb->get_tables()) {
            // not tables yet, time to create all tables
            $this->manager->install_from_xmldb_structure($this->schema);
        }

        if (round($version, 2) !== round($CFG->version, 2)) { // version might be in decimal format too
            $a = (object)array('schemaver'=>$version, 'currentver'=>$CFG->version);
            throw new dbtransfer_exception('importversionmismatchexception', $a);
        }

        if ($this->check_schema and $errors = $this->manager->check_database_schema($this->schema)) {
            $details = '';
            foreach ($errors as $table=>$items) {
                $details .= '<div>'.get_string('table').' '.$table.':';
                $details .= '<ul>';
                foreach ($items as $item) {
                    $details .= '<li>'.$item.'</li>';
                }
                $details .= '</ul></div>';
            }
            throw new dbtransfer_exception('importschemaexception', $details);
        }
        if ($this->transactionmode == 'allinone') {
            $this->transaction = $this->mdb->start_delegated_transaction();
        }
    }

    public function begin_table_import($tablename, $schemaHash) {
        if ($this->transactionmode == 'pertable') {
            $this->transaction = $this->mdb->start_delegated_transaction();
        }
        if (!$table = $this->schema->getTable($tablename)) {
            throw new dbtransfer_exception('unknowntableexception', $tablename);
        }
        if ($schemaHash != $table->getHash()) {
            throw new dbtransfer_exception('differenttableexception', $tablename);
        }
        // this should not happen, unless someone drops tables after import started
        if (!$this->manager->table_exists($table)) {
            throw new ddl_table_missing_exception($tablename);
        }
        $this->mdb->delete_records($tablename);
    }

    public function finish_table_import($tablename) {
        $table  = $this->schema->getTable($tablename);
        $fields = $table->getFields();
        foreach ($fields as $field) {
            if ($field->getSequence()) {
                $this->manager->reset_sequence($tablename);
                return;
            }
        }
        if ($this->transactionmode == 'pertable') {
            $this->transaction->allow_commit();
        }
    }

    public function finish_database_import() {
        if ($this->transactionmode == 'allinone') {
            $this->transaction->allow_commit();
        }
    }

    public function import_table_data($tablename, $data) {
        $this->mdb->import_record($tablename, $data);
    }

    public function import_database() {
        // implement in subclasses
    }
}