<xs:sequence>
<xs:element maxOccurs="unbounded" name="table" type="tableType" />
</xs:sequence>
- <xs:attribute name="version" type="xs:positiveInteger" use="required" />
+ <xs:attribute name="version" type="xs:float" use="required" />
<xs:attribute name="timestamp" type="xs:dateTime" use="required" />
<xs:attribute name="comment" type="xs:string" />
</xs:complexType>
--- /dev/null
+<?php //$Id$
+
+/**
+ * General database import classes
+ * @author Andrei Bautu
+ * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
+ * @package dbtransfer
+ */
+
+/**
+ * Base class for database export operations. This class defines basic callbacks
+ * for export operations and implements the @see export_database and
+ * @export_table methods generic export processing. In general, subclasses will
+ * override callback methods to provide specific output and (optionally)
+ * @see export_database to add functionality.
+ * Between a single pair of calls to @see begin_database_export and
+ * @see finish_database_export, multiple non-overlapping pairs of calls may
+ * be made to @see begin_table_export and @see finish_database_export for
+ * different tables. Between one pair of calls to @see begin_table_export and
+ * @see finish_database_export multiple calls may be made to
+ * @see export_table_data for the same table.
+ */
+abstract class database_exporter {
+ /** Connection to the source database (a @see moodle_database object). */
+ protected $mdb;
+ /** Database manager of the source database (a @see database_manager object). */
+ protected $manager;
+ /** Source database schema in XMLDB format (a @see xmldb_structure object). */
+ protected $schema;
+ /**
+ * Boolean flag - whether or not to check that XML database schema matches
+ * the RDBMS database schema before exporting (used by
+ * @see export_database).
+ */
+ protected $check_schema;
+
+ /**
+ * Object constructor.
+ *
+ * @param moodle_database $mdb Connection to the source database (a
+ * @see moodle_database object).
+ * @param xmldb_structure $schema Source database schema in XMLDB format (a
+ * @see xmldb_structure object). Use null to load the schema from the
+ * system's install.xml files.
+ * @param boolean $check_schema - whether or not to check that XML database
+ * schema matches the RDBMS database schema before exporting (used by
+ * @see export_database).
+ */
+ public function __construct(moodle_database $mdb, xmldb_structure $schema=null, $check_schema=true) {
+ if (is_null($schema)) {
+ $schema = database_manager::get_install_xml_schema();
+ }
+ $this->mdb = $mdb;
+ $this->manager = $mdb->get_manager();
+ $this->schema = $schema;
+ $this->check_schema = $check_schema;
+ }
+
+ /**
+ * Callback function. Should be called only once database per export
+ * operation, before any other export operations. Subclasses should export
+ * basic database information (version and timestamp).
+ *
+ * @param float $version the version of the system which generating the data
+ * @param string $timestamp the timestamp of the data (in ISO 8601) format.
+ * @param string $description a user description of the data.
+ * @return void
+ */
+ public function begin_database_export($version, $timestamp, $description) {
+ }
+
+ /**
+ * Callback function. Should be called only once per table export operation,
+ * before any other table export operations. Subclasses should export
+ * basic database information (name and schema's hash).
+ *
+ * @param xmldb_table $table - XMLDB object for the exported table
+ * @return void
+ */
+ public function begin_table_export(xmldb_table $table) {
+ }
+
+ /**
+ * Callback function. Should be called only once per table export operation,
+ * after all other table export operations.
+ *
+ * @param xmldb_table $table - XMLDB object for the exported table
+ */
+ public function finish_table_export(xmldb_table $table) {
+ }
+
+ /**
+ * Callback function. Should be called only once database per export
+ * operation, after all database export operations.
+ */
+ public function finish_database_export() {
+ }
+
+ /**
+ * Callback function. Should be called only once per record export operation,
+ * only between @see begin_table_export and @see finish_table_export calls.
+ * It will insert table data. Subclasses should export basic record
+ * information (data values).
+ *
+ * @param xmldb_table $table - XMLDB object of the table from which data was retrived
+ * @param object $data - data object (fields and values from record)
+ * @return void
+ */
+ public abstract function export_table_data(xmldb_table $table, $data);
+
+ /**
+ * Generic method to export the database. It checks the schema (if
+ * @see $check_schema is true), queries the database and calls
+ * appropiate callbacks.
+ *
+ * @exception export_exception if any checking (e.g. database schema) fails
+ *
+ * @param string $description a user description of the data.
+ */
+ public function export_database($description=null) {
+ global $CFG;
+
+ if ($this->check_schema && $this->manager->check_database_schema($this->schema)) {
+ //TODO put message in error lang
+ throw new export_exception('XMLDB schema does not match database schema.');
+ }
+ $tables = $this->schema->getTables();
+ $this->begin_database_export($CFG->version, date('c'), $description);
+ foreach ($tables as $table) {
+ $rs = $this->mdb->get_recordset_sql('SELECT * FROM {'.$table->getName().'}');
+ //TODO remove this when dml will have exceptions
+ if (!$rs) {
+ //TODO put message in error lang
+ throw new export_exception('An error occured while reading the database.');
+ }
+ $this->begin_table_export($table);
+ foreach ($rs as $row) {
+ $this->export_table_data($table, $row);
+ }
+ $this->finish_table_export($table);
+ }
+ $this->finish_database_export();
+ }
+
+}
+
+/**
+ * XML format exporter class.
+ * Provides logic for writing XML tags and data inside appropiate callbacks.
+ * Subclasses should define XML data sinks.
+ */
+abstract class xml_database_exporter extends database_exporter {
+ /**
+ * Generic output method. Subclasses should implement it with code specific
+ * to the target XML sink.
+ */
+ protected abstract function output($text);
+
+ /**
+ * Callback function. Outputs open XML PI and moodle_database opening tag.
+ *
+ * @param float $version the version of the system which generating the data
+ * @param string $timestamp the timestamp of the data (in ISO 8601) format.
+ * @param string $description a user description of the data.
+ * @return void
+ */
+ public function begin_database_export($version, $timestamp, $description) {
+ $this->output('<?xml version="1.0" encoding="utf-8"?>');
+ //TODO add xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" and schema information
+ $this->output('<moodle_database version="'.$version.'" timestamp="'.$timestamp.'"'.(empty ($description) ? '' : ' comment="'.htmlspecialchars($description, ENT_QUOTES).'"').'>');
+ }
+
+ /**
+ * Callback function. Outputs table opening tag.
+ *
+ * @param xmldb_table $table - XMLDB object for the exported table
+ * @return void
+ */
+ public function begin_table_export(xmldb_table $table) {
+ $this->output('<table name="'.$table->getName().'" schemaHash="'.$table->getHash().'">');
+ }
+
+ /**
+ * Callback function. Outputs table closing tag.
+ *
+ * @param xmldb_table $table - XMLDB object for the exported table
+ */
+ public function finish_table_export(xmldb_table $table) {
+ $this->output('</table>');
+ }
+
+ /**
+ * Callback function. Outputs moodle_database closing tag.
+ */
+ public function finish_database_export() {
+ $this->output('</moodle_database>');
+ }
+
+ /**
+ * Callback function. Outputs record tag with field subtags and data.
+ *
+ * @param xmldb_table $table - XMLDB object of the table from which data was retrived
+ * @param object $data - data object (fields and values from record)
+ * @return void
+ */
+ public function export_table_data(xmldb_table $table, $data) {
+ $this->output('<record>');
+ foreach ($data as $key => $value) {
+ if (is_null($value)) {
+ $this->output('<field name="'.$key.'" value="null" />');
+ } else {
+ $this->output('<field name="'.$key.'">'.htmlspecialchars($value, ENT_NOQUOTES).'</field>');
+ }
+ }
+ $this->output('</record>');
+ }
+}
+
+/**
+ * XML format exporter class to file storage.
+ */
+class file_xml_database_exporter extends xml_database_exporter {
+ /** Path to the XML data file. */
+ protected $filepath;
+ /** File descriptor for the output file. */
+ protected $file;
+
+ /**
+ * Object constructor.
+ *
+ * @param string $filepath - path to the XML data file. Use null for PHP
+ * output stream.
+ * @param moodle_database $mdb Connection to the source database
+ * @see xml_database_exporter::__construct()
+ * @param xmldb_structure $schema Source database schema in XMLDB format
+ * @see xml_database_exporter::__construct()
+ * @param boolean $check_schema - whether or not to check that XML database
+ * @see xml_database_exporter::__construct()
+ */
+ function __construct($filepath, moodle_database $mdb, xmldb_structure $schema=null, $check_schema=true) {
+ parent::__construct($mdb, $schema, $check_schema);
+ if (is_null($filepath)) {
+ $filepath = 'php://output';
+ }
+ $this->filepath = $filepath;
+ }
+
+ /**
+ * Specific output method for the file XML sink.
+ */
+ protected function output($text) {
+ fwrite($this->file, $text);
+ }
+
+ /**
+ * Specific implementation for file exporting the database: it opens output stream, calls
+ * superclass @see database_exporter::export_database() and closes output stream.
+ *
+ * @exception export_exception if any checking (e.g. database schema) fails
+ *
+ * @param string $description a user description of the data.
+ */
+ public function export_database($description=null) {
+ $this->file = fopen($this->filepath, 'wb');
+ parent::export_database($description);
+ fclose($this->file);
+ }
+}
+
+/**
+ * XML format exporter class to memory storage (i.e. a string).
+ */
+class string_xml_database_exporter extends xml_database_exporter {
+ /** String with XML data. */
+ protected $data;
+
+ /**
+ * Specific output method for the memory XML sink.
+ */
+ protected function output($text) {
+ $this->data .= $text;
+ }
+
+ /**
+ * Returns the output of the exporters
+ * @return string XML data from exporter
+ */
+ public function get_output() {
+ return $this->data;
+ }
+
+ /**
+ * Specific implementation for memory exporting the database: it clear the buffer
+ * and calls superclass @see database_exporter::export_database().
+ *
+ * @exception export_exception if any checking (e.g. database schema) fails
+ * @param string $description a user description of the data.
+ * @return void
+ */
+ public function export_database($description=null) {
+ $this->data = '';
+ parent::export_database($description);
+ }
+}
+
+class database_mover extends database_exporter {
+ /** Importer object used to transfer data. */
+ protected $importer;
+
+ /**
+ * Object constructor.
+ *
+ * @param moodle_database $mdb_target Connection to the target database (a
+ * @see moodle_database object).
+ * @param moodle_database $mdb Connection to the source database (a
+ * @see moodle_database object).
+ * @param xmldb_structure $schema Source database schema in XMLDB format (a
+ * @see xmldb_structure object). Use null to load the schema from the
+ * system's install.xml files.
+ * @param boolean $check_schema - whether or not to check that XML database
+ * schema matches the RDBMS database schema before exporting (used by
+ * @see export_database).
+ */
+ public function __construct(moodle_database $mdb_target, moodle_database $mdb_source, xmldb_structure $schema=null, $check_schema=true) {
+ parent::__construct($mdb_source, $schema, $check_schema);
+ $this->importer = new database_importer($mdb_target, $schema, $check_schema);
+ }
+
+ /**
+ * Callback function. Calls importer's begin_database_import callback method.
+ *
+ * @param float $version the version of the system which generating the data
+ * @param string $timestamp the timestamp of the data (in ISO 8601) format.
+ * @param string $description a user description of the data.
+ * @return void
+ */
+ public function begin_database_export($version, $timestamp, $description) {
+ $this->importer->init_database();
+ $this->importer->begin_database_import($version, $timestamp, $description);
+ }
+
+ /**
+ * Callback function. Calls importer's begin_table_import callback method.
+ *
+ * @param xmldb_table $table - XMLDB object for the exported table
+ * @return void
+ */
+ public function begin_table_export(xmldb_table $table) {
+ $this->importer->begin_table_import($table->getName(), $table->getHash());
+ }
+
+ /**
+ * Callback function. Calls importer's import_table_data callback method.
+ *
+ * @param xmldb_table $table - XMLDB object of the table from which data
+ * was retrived
+ * @param object $data - data object (fields and values from record)
+ * @return void
+ */
+ public function export_table_data(xmldb_table $table, $data) {
+ $this->importer->import_table_data($table->getName(), $data);
+ }
+
+ /**
+ * Callback function. Calls importer's finish_table_import callback method.
+ * @param xmldb_table $table - XMLDB object for the exported table
+ * @return void
+ */
+ public function finish_table_export(xmldb_table $table) {
+ $this->importer->finish_table_import($table->getName());
+ }
+
+ /**
+ * Callback function. Calls importer's finish_database_import callback method.
+ * @return void
+ */
+ public function finish_database_export() {
+ $this->importer->finish_database_import();
+ }
+}
--- /dev/null
+<?php //$Id$
+
+/**
+ * General database import classes
+ * @author Andrei Bautu
+ * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
+ * @package dbtransfer
+ */
+
+/**
+ * Base class for database import operations. This class implements
+ * basic callbacks for import operations and defines the @see import_database
+ * method as a common method for all importers. In general, subclasses will
+ * override import_database and call other methods in appropriate moments.
+ * Between a single pair of calls to @see begin_database_import and
+ * @see finish_database_import, multiple non-overlapping pairs of calls may
+ * be made to @see begin_table_import and @see finish_database_import for
+ * different tables.
+ * Between one pair of calls to @see begin_table_import and
+ * @see finish_database_import multiple calls may be made to
+ * @see import_table_data for the same table.
+ * This class can be used directly, if the standard control flow (defined above)
+ * is respected.
+ */
+class database_importer {
+ /** Connection to the target database (a @see moodle_database object). */
+ protected $mdb;
+ /** Database manager of the target database (a @see database_manager object). */
+ protected $manager;
+ /** Target database schema in XMLDB format (a @see xmldb_structure object). */
+ protected $schema;
+ /**
+ * Boolean flag - whether or not to check that XML database schema matches
+ * the RDBMS database schema before importing (used by
+ * @see begin_database_import).
+ */
+ protected $check_schema;
+
+ /**
+ * Object constructor.
+ *
+ * @param moodle_database $mdb Connection to the target database (a
+ * @see moodle_database object). Use null to use the curent $DB connection.
+ * @param xmldb_structure $schema Target database schema in XMLDB format (a
+ * @see xmldb_structure object). Use null to load the schema from the
+ * system's install.xml files.
+ * @param boolean $check_schema - whether or not to check that XML database
+ * schema matches the RDBMS database schema before importing (inside
+ * @see begin_database_import).
+ */
+ public function __construct(moodle_database $mdb, xmldb_structure $schema=null, $check_schema=true) {
+ if (is_null($schema)) {
+ $schema = database_manager::get_install_xml_schema();
+ }
+ $this->mdb = $mdb;
+ $this->manager = $mdb->get_manager();
+ $this->schema = $schema;
+ $this->check_schema = $check_schema;
+ }
+
+ /**
+ * Callback function. Should be called only once database per import
+ * operation, before any database changes are made. It will check the database
+ * schema if @see check_schema is true
+ *
+ * @exception import_exception if any checking (e.g. database schema, Moodle
+ * version) fails
+ *
+ * @param float $version the version of the system which generated the data
+ * @param string $timestamp the timestamp of the data (in ISO 8601) format.
+ * @return void
+ */
+ public function begin_database_import($version, $timestamp) {
+ global $CFG;
+
+ if (round($version, 2) !== round($CFG->version, 2)) { // version might be in decimal format too
+ //TODO put message in error lang
+ throw new import_exception('Current Moodle version does not match exported Moodle version.');
+ }
+ if ($this->check_schema && $this->manager->check_database_schema($this->schema)) {
+ //TODO put message in error lang
+ throw new import_exception('XMLDB schema does not match database schema.');
+ }
+ $this->mdb->begin_sql();
+ }
+
+ /**
+ * Callback function. Should be called only once per table import operation,
+ * before any table changes are made. It will delete all table data.
+ *
+ * @exception import_exception an unknown table import is attempted
+ * @exception ddl_table_missing_exception if the table is missing
+ *
+ * @param string $tablename - the name of the table that will be imported
+ * @param string $schemaHash - the hash of the xmldb_table schema of the table
+ * @return void
+ */
+ public function begin_table_import($tablename, $schemaHash) {
+ $table = $this->schema->getTable($tablename);
+ if (is_null($table)) {
+ //TODO put message in error lang
+ throw new import_exception('Unknown table in import data');
+ }
+ if ($schemaHash != $table->getHash()) {
+ throw new import_exception('XMLDB schema does not match database schema.');
+ }
+ // this should not happen, unless someone drops tables after import started
+ if (!$this->manager->table_exists($table)) {
+ // in the future, missing tables will be recreated with
+ //$this->manager->create_table($table);
+ throw new ddl_table_missing_exception($tablename);
+ }
+ $this->mdb->delete_records($tablename);
+ }
+
+ /**
+ * Callback function. Should be called only once per table import operation,
+ * after all table changes are made. It will reset table sequences if any.
+ * @param string $tablename
+ * @return void
+ */
+ public function finish_table_import($tablename) {
+ $table = $this->schema->getTable($tablename);
+ $fields = $table->getFields();
+ foreach ($fields as $field) {
+ if ($field->getSequence()) {
+ //TODO make sure that there aren't tables using two sequences (probably there is none)
+ $this->mdb->reset_sequence($tablename);
+ return;
+ }
+ }
+ }
+
+ /**
+ * Callback function. Should be called only once database per import
+ * operation, after all database changes are made. It will commit changes.
+ * @return void
+ */
+ public function finish_database_import() {
+ $this->mdb->commit_sql();
+ }
+
+ /**
+ * Callback function. Should be called only once per record import operation, only
+ * between @see begin_table_import and @see finish_table_import calls.
+ * It will insert table data.
+ *
+ * @exception dml_exception if data insert operation failed
+ *
+ * @param string $tablename - the name of the table in which data will be
+ * imported
+ * @param object $data - data object (fields and values will be inserted
+ * into table)
+ * @return void
+ */
+ public function import_table_data($tablename, $data) {
+ $this->mdb->import_record($tablename, $data);
+ }
+
+ /**
+ * All subclases must call this
+ * @return void
+ */
+ public function init_database() {
+ if (!$this->mdb->get_tables()) {
+ // not tables yet, time to create all tables
+ $this->manager->install_from_xmldb_structure($this->schema);
+ }
+ }
+}
+
+/**
+ * XML format importer class (uses SAX for speed and low memory footprint).
+ * Provides logic for parsing XML data and calling appropiate callbacks.
+ * Subclasses should define XML data sources.
+ */
+abstract class xml_database_importer extends database_importer {
+ /**
+ * Creates and setups a SAX parser. Subclasses should use this method to
+ * create the XML parser.
+ *
+ * @return resource XML parser resource.
+ */
+ protected function get_parser() {
+ $parser = xml_parser_create();
+ xml_set_object($parser, $this);
+ xml_set_element_handler($parser, 'tag_open', 'tag_close');
+ xml_set_character_data_handler($parser, 'cdata');
+ xml_parser_set_option($parser, XML_OPTION_CASE_FOLDING, false);
+ return $parser;
+ }
+
+ /**
+ * Callback function. Called by the XML parser for opening tags processing.
+ *
+ * @param resource $parser XML parser resource.
+ * @param string $tag name of opening tag
+ * @param array $attributes set of opening tag XML attributes
+ * @return void
+ */
+ protected function tag_open($parser, $tag, $attributes) {
+ switch ($tag) {
+ case 'moodle_database' :
+ $this->begin_database_import($attributes['version'], $attributes['timestamp']);
+ break;
+ case 'table' :
+ $this->current_table = $attributes['name'];
+ $this->begin_table_import($this->current_table, $attributes['schemaHash']);
+ break;
+ case 'record' :
+ $this->current_row = new object();
+ break;
+ case 'field' :
+ $this->current_field = $attributes['name'];
+ $this->current_data = @$attributes['value'] == 'null' ? null : '';
+ break;
+ default :
+ //TODO put message in error lang
+ throw new import_exception('XML content not valid for import operation.');
+ }
+ }
+
+ /**
+ * Callback function. Called by the XML parser for closing tags processing.
+ *
+ * @param resource $parser XML parser resource.
+ * @param string $tag name of opening tag
+ * @return void
+ */
+ protected function tag_close($parser, $tag) {
+ switch ($tag) {
+ case 'moodle_database' :
+ $this->finish_database_import();
+ break;
+ case 'table' :
+ $this->finish_table_import($this->current_table);
+ unset ($this->current_table);
+ break;
+ case 'record' :
+ $this->import_table_data($this->current_table, $this->current_row);
+ unset ($this->current_row);
+ break;
+ case 'field' :
+ $field = $this->current_field;
+ unset ($this->current_field);
+ $this->current_row-> $field = $this->current_data;
+ unset ($this->current_data);
+ break;
+ default :
+ //TODO put message in error lang
+ throw new import_exception('XML content not valid for import operation.');
+ }
+ }
+
+ /**
+ * Callback function. Called by the XML parser for character data processing.
+ *
+ * @param resource $parser XML parser resource.
+ * @param string $data character data to be processed
+ * @return void
+ */
+ protected function cdata($parser, $cdata) {
+ if (isset($this->current_field)) {
+ $this->current_data .= $cdata;
+ }
+ }
+
+ /**
+ * Common import method
+ * @return void
+ */
+ public abstract function import_database();
+}
+
+/**
+ * XML format importer class from file storage.
+ */
+class file_xml_database_importer extends xml_database_importer {
+ /** Path to the XML data file. */
+ protected $filepath;
+
+ /**
+ * Object constructor.
+ *
+ * @param string $filepath - path to the XML data file. Use null for PHP
+ * input stream.
+ * @param moodle_database $mdb Connection to the target database
+ * @see xml_database_importer::__construct()
+ * @param xmldb_structure $schema Target database schema in XMLDB format
+ * @see xml_database_importer::__construct()
+ * @param boolean $check_schema - whether or not to check that XML database
+ * @see xml_database_importer::__construct()
+ */
+ public function __construct($filepath, moodle_database $mdb, xmldb_structure $schema=null) {
+ parent::__construct($mdb, $schema);
+ if (is_null($filepath)) {
+ $filepath = 'php://input';
+ }
+ $this->filepath = $filepath;
+ }
+
+ /**
+ * Common import method: it opens the file storage, creates the parser, feeds
+ * the XML parser with data, releases the parser and closes the file storage.
+ * @return void
+ */
+ public function import_database() {
+ $this->init_database();
+ $file = fopen($this->filepath, 'r');
+ $parser = $this->get_parser();
+ while (($data = fread($file, 65536)) && xml_parse($parser, $data, feof($file)));
+ xml_parser_free($parser);
+ fclose($file);
+ }
+}
+
+/**
+ * XML format importer class from memory storage (i.e. string).
+ */
+class string_xml_database_importer extends xml_database_importer {
+ /** String with XML data. */
+ protected $data;
+
+ /**
+ * Object constructor.
+ *
+ * @param string data - string with XML data
+ * @param moodle_database $mdb Connection to the target database
+ * @see xml_database_importer::__construct()
+ * @param xmldb_structure $schema Target database schema in XMLDB format
+ * @see xml_database_importer::__construct()
+ * @param boolean $check_schema - whether or not to check that XML database
+ * @see xml_database_importer::__construct()
+ */
+ public function __construct($data, moodle_database $mdb, xmldb_structure $schema=null) {
+ parent::__construct($mdb, $schema);
+ $this->data = $data;
+ }
+
+ /**
+ * Common import method: it creates the parser, feeds the XML parser with
+ * data, releases the parser.
+ * @return void
+ */
+ public function import_database() {
+ $this->init_database();
+ $parser = $this->get_parser();
+ xml_parse($parser, $this->data, true);
+ xml_parser_free($parser);
+ }
+}
--- /dev/null
+<?php //$Id$
+
+/**
+ * Database transfer related code.
+ * @author Andrei Bautu
+ * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
+ * @package dbtransfer
+*/
+
+require_once $CFG->libdir.'/xmldb/xmldb_structure.php';
+require_once $CFG->libdir.'/ddl/database_manager.php';
+require_once $CFG->dirroot.'/'.$CFG->admin.'/dbtransfer/exportlib.php';
+require_once $CFG->dirroot.'/'.$CFG->admin.'/dbtransfer/importlib.php';
+
+/**
+ * Exception class for export operations.
+ * @see moodle_exception
+ * TODO subclass for specific purposes
+ */
+class export_exception extends moodle_exception {
+ function __construct($errorcode, $a=null, $debuginfo=null) {
+ parent::__construct($errorcode, '', '', $a, $debuginfo);
+ }
+}
+
+/**
+ * Exception class for import operations.
+ * @see moodle_exception
+ * TODO subclass for specific purposes
+ */
+class import_exception extends moodle_exception {
+ function __construct($errorcode, $a=null, $debuginfo=null) {
+ parent::__construct($errorcode, '', '', $a, $debuginfo);
+ }
+}