gnu-social/classes/Safe_DataObject.php

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<?php
/*
* StatusNet - the distributed open-source microblogging tool
* Copyright (C) 2010, StatusNet, Inc.
*
* 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/>.
*/
if (!defined('GNUSOCIAL')) { exit(1); }
/**
* Extended DB_DataObject to improve a few things:
* - free global resources from destructor
* - remove bogus global references from serialized objects
* - don't leak memory when loading already-used .ini files
* (eg when using the same schema on thousands of databases)
*/
class Safe_DataObject extends GS_DataObject
{
/**
* Destructor to free global memory resources associated with
* this data object when it's unset or goes out of scope.
* DB_DataObject doesn't do this yet by itself.
*/
function __destruct()
{
$this->free();
if (method_exists('DB_DataObject', '__destruct')) {
parent::__destruct();
}
}
/**
* Magic function called at clone() time.
*
* We use this to drop connection with some global resources.
* This supports the fairly common pattern where individual
* items being read in a loop via a single object are cloned
* for individual processing, then fall out of scope when the
* loop comes around again.
*
* As that triggers the destructor, we want to make sure that
* the original object doesn't have its database result killed.
* It will still be freed properly when the original object
* gets destroyed.
*/
function __clone()
{
$this->_DB_resultid = false;
}
/**
* Magic function called at serialize() time.
*
* We use this to drop a couple process-specific references
* from DB_DataObject which can cause trouble in future
* processes.
*
* @return array of variable names to include in serialization.
*/
function __sleep()
{
$vars = array_keys(get_object_vars($this));
$skip = array('_DB_resultid', '_link_loaded');
return array_diff($vars, $skip);
}
/**
* Magic function called at unserialize() time.
*
* Clean out some process-specific variables which might
* be floating around from a previous process's cached
* objects.
*
* Old cached objects may still have them.
*/
function __wakeup()
{
// Refers to global state info from a previous process.
// Clear this out so we don't accidentally break global
// state in *this* process.
$this->_DB_resultid = null;
// We don't have any local DBO refs, so clear these out.
$this->_link_loaded = false;
}
/**
* Magic function called when someone attempts to call a method
* that doesn't exist. DB_DataObject uses this to implement
* setters and getters for fields, but neglects to throw an error
* when you just misspell an actual method name. This leads to
* silent failures which can cause all kinds of havoc.
*
* @param string $method
* @param array $params
* @return mixed
* @throws Exception
*/
function __call($method, $params)
{
$return = null;
// Yes, that's _call with one underscore, which does the
// actual implementation.
if ($this->_call($method, $params, $return)) {
return $return;
} else {
// Low level exception. No need for i18n as discussed with Brion.
throw new Exception('Call to undefined method ' .
get_class($this) . '::' . $method);
}
}
/**
* Work around memory-leak bugs...
* Had to copy-paste the whole function in order to patch a couple lines of it.
* Would be nice if this code was better factored.
*
* @param optional string name of database to assign / read
* @param optional array structure of database, and keys
* @param optional array table links
*
* @access public
* @return true or PEAR:error on wrong paramenters.. or false if no file exists..
* or the array(tablename => array(column_name=>type)) if called with 1 argument.. (databasename)
*/
function databaseStructure()
{
global $_DB_DATAOBJECT;
// Assignment code
if ($args = func_get_args()) {
if (count($args) == 1) {
// this returns all the tables and their structure..
if (!empty($_DB_DATAOBJECT['CONFIG']['debug'])) {
$this->debug("Loading Generator as databaseStructure called with args",1);
}
$x = new DB_DataObject;
$x->_database = $args[0];
$this->_connect();
$DB = &$_DB_DATAOBJECT['CONNECTIONS'][$this->_database_dsn_md5];
$tables = $DB->getListOf('tables');
class_exists('DB_DataObject_Generator') ? '' :
require_once 'DB/DataObject/Generator.php';
foreach($tables as $table) {
$y = new DB_DataObject_Generator;
$y->fillTableSchema($x->_database,$table);
}
return $_DB_DATAOBJECT['INI'][$x->_database];
} else {
$_DB_DATAOBJECT['INI'][$args[0]] = isset($_DB_DATAOBJECT['INI'][$args[0]]) ?
$_DB_DATAOBJECT['INI'][$args[0]] + $args[1] : $args[1];
if (isset($args[1])) {
$_DB_DATAOBJECT['LINKS'][$args[0]] = isset($_DB_DATAOBJECT['LINKS'][$args[0]]) ?
$_DB_DATAOBJECT['LINKS'][$args[0]] + $args[2] : $args[2];
}
return true;
}
}
if (!$this->_database) {
$this->_connect();
}
// loaded already?
if (!empty($_DB_DATAOBJECT['INI'][$this->_database])) {
// database loaded - but this is table is not available..
if (
empty($_DB_DATAOBJECT['INI'][$this->_database][$this->__table])
&& !empty($_DB_DATAOBJECT['CONFIG']['proxy'])
) {
if (!empty($_DB_DATAOBJECT['CONFIG']['debug'])) {
$this->debug("Loading Generator to fetch Schema",1);
}
class_exists('DB_DataObject_Generator') ? '' :
require_once 'DB/DataObject/Generator.php';
$x = new DB_DataObject_Generator;
$x->fillTableSchema($this->_database,$this->__table);
}
return true;
}
if (empty($_DB_DATAOBJECT['CONFIG'])) {
self::_loadConfig();
}
// if you supply this with arguments, then it will take those
// as the database and links array...
$schemas = isset($_DB_DATAOBJECT['CONFIG']['schema_location']) ?
array("{$_DB_DATAOBJECT['CONFIG']['schema_location']}/{$this->_database}.ini") :
array() ;
if (isset($_DB_DATAOBJECT['CONFIG']["ini_{$this->_database}"])) {
$schemas = is_array($_DB_DATAOBJECT['CONFIG']["ini_{$this->_database}"]) ?
$_DB_DATAOBJECT['CONFIG']["ini_{$this->_database}"] :
explode(PATH_SEPARATOR,$_DB_DATAOBJECT['CONFIG']["ini_{$this->_database}"]);
}
/* BEGIN CHANGED FROM UPSTREAM */
$_DB_DATAOBJECT['INI'][$this->_database] = $this->parseIniFiles($schemas);
/* END CHANGED FROM UPSTREAM */
// now have we loaded the structure..
if (!empty($_DB_DATAOBJECT['INI'][$this->_database][$this->__table])) {
return true;
}
// - if not try building it..
if (!empty($_DB_DATAOBJECT['CONFIG']['proxy'])) {
class_exists('DB_DataObject_Generator') ? '' :
require_once 'DB/DataObject/Generator.php';
$x = new DB_DataObject_Generator;
$x->fillTableSchema($this->_database,$this->__table);
// should this fail!!!???
return true;
}
$this->debug("Cant find database schema: {$this->_database}/{$this->__table} \n".
"in links file data: " . print_r($_DB_DATAOBJECT['INI'],true),"databaseStructure",5);
// we have to die here!! - it causes chaos if we don't (including looping forever!)
// Low level exception. No need for i18n as discussed with Brion.
$this->raiseError( "Unable to load schema for database and table (turn debugging up to 5 for full error message)", DB_DATAOBJECT_ERROR_INVALIDARGS, PEAR_ERROR_DIE);
return false;
}
/** For parseIniFiles */
protected static $iniCache = array();
/**
* When switching site configurations, DB_DataObject was loading its
* .ini files over and over, leaking gobs of memory.
* This refactored helper function uses a local cache of .ini files
* to minimize the leaks.
*
* @param array of .ini file names $schemas
* @return array
*/
protected function parseIniFiles(array $schemas)
{
$key = implode("|", $schemas);
if (!isset(Safe_DataObject::$iniCache[$key])) {
$data = array();
foreach ($schemas as $ini) {
if (file_exists($ini) && is_file($ini)) {
$data = array_merge($data, parse_ini_file($ini, true));
if (!empty($_DB_DATAOBJECT['CONFIG']['debug'])) {
if (!is_readable ($ini)) {
$this->debug("ini file is not readable: $ini","databaseStructure",1);
} else {
$this->debug("Loaded ini file: $ini","databaseStructure",1);
}
}
} else {
if (!empty($_DB_DATAOBJECT['CONFIG']['debug'])) {
$this->debug("Missing ini file: $ini","databaseStructure",1);
}
}
}
Safe_DataObject::$iniCache[$key] = $data;
}
return Safe_DataObject::$iniCache[$key];
}
}