Adjust copyrights years
<?php
/**
* SeekQuarry/Yioop --
* Open Source Pure PHP Search Engine, Crawler, and Indexer
*
* Copyright (C) 2009 - 2024 Chris Pollett chris@pollett.org
*
* LICENSE:
*
* 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 3 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, see <https://www.gnu.org/licenses/>.
*
* END LICENSE
*
* @author Chris Pollett chris@pollett.org
* @license https://www.gnu.org/licenses/ GPL3
* @link https://www.seekquarry.com/
* @copyright 2009 - 2024
* @filesource
*/
namespace seekquarry\yioop\library;
/**
* A PersistentStructure is a data structure which every so many operations
* will be saved to secondary storage (such as disk).
* An operation occurs whenever the PersistentStructure's checkSave method is
* called. A PersistentStructure also supports the ability to be load
* (read in from) secondary storage.
*
* @author Chris Pollett
*/
class PersistentStructure
{
/** If not specified in the constructor, this will be the number of
* operations between saves
* @var int
*/
const DEFAULT_SAVE_FREQUENCY = 50000;
/** Name of the file in which to store the PersistentStructure
* @var string
*/
public $filename;
/** Number of operations since the last save
* @var int
*/
public $unsaved_operations;
/** Number of operation between saves. If == -1 never save using checkSave
* @var int
*/
public $save_frequency;
/**
* Sets up the file name and save frequency for the PersistentStructure,
* initializes the oepration count
*
* @param string $fname the name of the file to store the
* PersistentStructure in
* @param int $save_frequency the number of operation before a save If
* <= 0 never check save
*/
public function __construct($fname,
$save_frequency = self::DEFAULT_SAVE_FREQUENCY)
{
$this->filename = $fname;
$this->save_frequency = $save_frequency;
$this->unsaved_operations = 0;
}
/**
* Load a PersistentStructure from a file
*
* @param string $fname the name of the file to load the
* PersistentStructure from
* @return object the PersistentStructure loaded
*/
public static function load($fname)
{
/* code to handle the fact that name space of object may not be the
modern namespace
*/
$obj_string = file_get_contents($fname);
$name_length = intval(substr($obj_string, 2, 14));
$name_space_info_length = strlen("O:".$name_length.":") + $name_length
+ 2; // 2 for quotes;
$actual_name = get_called_class();
$obj_string = 'O:' . strlen($actual_name) . ':"'.$actual_name.'"' .
substr($obj_string, $name_space_info_length);
return unserialize($obj_string);
}
/**
* Save the PersistentStructure to its filename
* This method is generic but super memory inefficient, so reimplement
* for subclasses is needed
*/
public function save()
{
file_put_contents($this->filename, serialize($this));
}
/**
* Add one to the unsaved_operations count. If this goes above the
* save_frquency then save the PersistentStructure to secondary storage
*/
public function checkSave()
{
$this->unsaved_operations++;
if ($this->save_frequency > 0 &&
$this->unsaved_operations >= $this->save_frequency) {
$this->save();
$this->unsaved_operations = 0;
}
}
}