<?php
/* Copyright (c) 1998-2009 ILIAS open source, Extended GPL, see docs/LICENSE */

/**
 * Cache class. The cache class stores key/value pairs. Since the primary
 * key is only one text field. It's sometimes necessary to combine parts
 * like "100:200" for user id 100 and ref_id 200.
 *
 * However sometimes records should be deleted by pars of the main key. For
 * this reason up to two optional additional optional integer and two additional
 * optional text fields can be stored. A derived class may delete records
 * based on the content of this additional keys.
 * 
 * @author Alex Killing <alex.killing@gmx.de>
 * @version $Id: class.ilCache.php 22483 2009-12-03 15:32:29Z smeyer $
 * @ingroup ingroup ServicesCache
 */
class ilCache
{
	/**
	 * Constructor
	 *
	 * @param
	 * @return
	 */
	function __construct($a_component, $a_cache_name, $a_use_long_content = false)
	{
		$this->setComponent($a_component);
		$this->setName($a_cache_name);
		$this->setUseLongContent($a_use_long_content);
	}
	
	/**
	 * Check if cache is disabled
	 * Forced if member view is active
	 * @return bool
	 */
	public function isDisabled()
	{
		include_once './Services/Container/classes/class.ilMemberViewSettings.php';
		return ilMemberViewSettings::getInstance()->isActive();
	}
	
	/**
	 * Set component
	 *
	 * @param	string	component
	 */
	function setComponent($a_val)
	{
		$this->component = $a_val;
	}
	
	/**
	 * Get component
	 *
	 * @return	string	component
	 */
	protected function getComponent()
	{
		return $this->component;
	}
	
	/**
	 * Set name
	 *
	 * @param	string	name
	 */
	protected function setName($a_val)
	{
		$this->name = $a_val;
	}
	
	/**
	 * Get name
	 *
	 * @return	string	name
	 */
	protected function getName()
	{
		return $this->name;
	}
	
	/**
	 * Set use long content
	 *
	 * @param	boolean	use long content
	 */
	protected function setUseLongContent($a_val)
	{
		$this->use_long_content = $a_val;
	}
	
	/**
	 * Get use long content
	 *
	 * @return	boolean	use long content
	 */
	protected function getUseLongContent()
	{
		return $this->use_long_content;
	}
	
	/**
	 * Set expires after x seconds
	 *
	 * @param	int	expires after x seconds
	 */
	public function setExpiresAfter($a_val)
	{
		$this->expires_after = $a_val;
	}
	
	/**
	 * Get expires after x seconds
	 *
	 * @return	int	expires after x seconds
	 */
	public function getExpiresAfter()
	{
		return $this->expires_after;
	}
	
	/**
	 * Get entry
	 *
	 * @param	string	entry id
	 * @return	string	entry value
	 */
	final public function getEntry($a_id)
	{
		if ($this->readEntry($a_id))	// cache hit
		{
			$this->last_access = "hit";
			return $this->entry;
		}
		$this->last_access = "miss";
	}
	
	/**
	 * Read entry
	 *
	 * @param
	 * @return
	 */
	protected function readEntry($a_id)
	{
		global $ilDB;
		
		$table = $this->getUseLongContent()
			? "cache_clob"
			: "cache_text";
	
		$query = "SELECT value FROM $table WHERE ".
			"component = ".$ilDB->quote($this->getComponent(), "text")." AND ".
			"name = ".$ilDB->quote($this->getName(), "text")." AND ".
			"expire_time > ".$ilDB->quote(time(), "integer")." AND ".
			"ilias_version = ".$ilDB->quote(ILIAS_VERSION_NUMERIC, "text")." AND ".
			"entry_id = ".$ilDB->quote($a_id, "text");
		
		$set = $ilDB->query($query);

		if ($rec  = $ilDB->fetchAssoc($set))
		{
			$this->entry = $rec["value"];
			return true;
		}

		return false;
	}
	
	/**
	 * Last access
	 */
	function getLastAccessStatus()
	{
		return $this->last_access;
	}
	
	
	/**
	 * Store entry
	 *
	 * @param	string		key
	 * @param	string		value
	 * @param	int			additional optional integer key
	 * @param	int			additional optional integer key
	 * @param	string		additional optional text key
	 * @param	string		additional optional text key
	 * @return
	 */
	function storeEntry($a_id, $a_value, $a_int_key1 = null, $a_int_key2 = null,
		$a_text_key1 = null, $a_text_key2 = null)
	{
		global $ilDB;

		$table = $this->getUseLongContent()
			? "cache_clob"
			: "cache_text";
		$type =  $this->getUseLongContent()
			? "clob"
			: "text";
			
		// do not store values, that do not fit into the text field
		if (strlen($a_value) > 4000 && $type == "text")
		{
			return;
		}

		$set = $ilDB->replace($table, array(
			"component" => array("text", $this->getComponent()),
			"name" => array("text", $this->getName()),
			"entry_id" => array("text", $a_id)
			), array (
			"value" => array($type, $a_value),
			"int_key_1" => array("integer", $a_int_key1),
			"int_key_2" => array("integer", $a_int_key2),
			"text_key_1" => array("text", $a_text_key1),
			"text_key_2" => array("text", $a_text_key2),
			"expire_time" => array("integer", (int) (time() + $this->getExpiresAfter())),
			"ilias_version" => array("text", ILIAS_VERSION_NUMERIC)
			));
			
		// In 1/2000 times, delete old entries
		$num = rand(1,2000);
		if ($num == 500)
		{
			$ilDB->manipulate("DELETE FROM $table WHERE ".
				" ilias_version <> ".$ilDB->quote(ILIAS_VERSION_NUMERIC, "text").
				" OR expire_time < ".$ilDB->quote(time(), "integer")
				);
		}
			
	}
	
	/**
	 * Delete by additional keys
	 */
	public function deleteByAdditionalKeys($a_int_key1 = null, $a_int_key2 = null,
		$a_text_key1 = null, $a_text_key2 = null)
	{
		global $ilDB;

		$table = $this->getUseLongContent()
			? "cache_clob"
			: "cache_text";
			
		$q = "DELETE FROM $table WHERE ".
			"component = ".$ilDB->quote($this->getComponent(), "text").
			" AND name = ".$ilDB->quote($this->getName(), "text");

		$fds = array("int_key_1" => array("v" => $a_int_key1, "t" => "integer"),
			"int_key_2" => array("v" => $a_int_key2, "t" => "integer"),
			"text_key_1" => array("v" => $a_text_key1, "t" => "text"),
			"text_key_2" => array("v" => $a_text_key2, "t" => "text"));
		$sep = " AND";
		foreach ($fds as $k => $fd)
		{
			if (!is_null($fd["v"]))
			{
				$q .= $sep." ".$k." = ".$ilDB->quote($fd["v"], $fd["t"]);
				$set = " AND";
			}
		}
		$ilDB->manipulate($q);
	}
	
	/**
	* Delete all entries of cache
	*/
	public function deleteAllEntries()
	{
		global $ilDB;

		$table = $this->getUseLongContent()
			? "cache_clob"
			: "cache_text";
			
		$q = "DELETE FROM $table WHERE ".
			"component = ".$ilDB->quote($this->getComponent(), "text").
			" AND name = ".$ilDB->quote($this->getName(), "text");
		$ilDB->manipulate($q);
	}

}
?>
