roundcubemail-plugins-kolab/plugins/libkolab/lib/kolab_storage_dataset.php

154 lines
3.7 KiB
PHP

<?php
/**
* Dataset class providing the results of a select operation on a kolab_storage_folder.
*
* Can be used as a normal array as well as an iterator in foreach() loops.
*
* @version @package_version@
* @author Thomas Bruederli <bruederli@kolabsys.com>
*
* Copyright (C) 2014, Kolab Systems AG <contact@kolabsys.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
class kolab_storage_dataset implements Iterator, ArrayAccess, Countable
{
private $cache; // kolab_storage_cache instance to use for fetching data
private $memlimit = 0;
private $buffer = false;
private $index = array();
private $data = array();
private $iteratorkey = 0;
private $error = null;
/**
* Default constructor
*
* @param object kolab_storage_cache instance to be used for fetching objects upon access
*/
public function __construct($cache)
{
$this->cache = $cache;
// enable in-memory buffering up until 1/5 of the available memory
if (function_exists('memory_get_usage')) {
$this->memlimit = parse_bytes(ini_get('memory_limit')) / 5;
$this->buffer = true;
}
}
/**
* Return error state
*/
public function is_error()
{
return !empty($this->error);
}
/**
* Set error state
*/
public function set_error($err)
{
$this->error = $err;
}
/*** Implement PHP Countable interface ***/
public function count()
{
return count($this->index);
}
/*** Implement PHP ArrayAccess interface ***/
public function offsetSet($offset, $value)
{
$uid = $value['_msguid'];
if (is_null($offset)) {
$offset = count($this->index);
$this->index[] = $uid;
}
else {
$this->index[$offset] = $uid;
}
// keep full payload data in memory if possible
if ($this->memlimit && $this->buffer && isset($value['_mailbox'])) {
$this->data[$offset] = $value;
// check memory usage and stop buffering
if ($offset % 10 == 0) {
$this->buffer = memory_get_usage() < $this->memlimit;
}
}
}
public function offsetExists($offset)
{
return isset($this->index[$offset]);
}
public function offsetUnset($offset)
{
unset($this->index[$offset]);
}
public function offsetGet($offset)
{
if (isset($this->data[$offset])) {
return $this->data[$offset];
}
else if ($msguid = $this->index[$offset]) {
return $this->cache->get($msguid);
}
return null;
}
/*** Implement PHP Iterator interface ***/
public function current()
{
return $this->offsetGet($this->iteratorkey);
}
public function key()
{
return $this->iteratorkey;
}
public function next()
{
$this->iteratorkey++;
return $this->valid();
}
public function rewind()
{
$this->iteratorkey = 0;
}
public function valid()
{
return !empty($this->index[$this->iteratorkey]);
}
}