web/Zend/Memory/Manager.php
changeset 0 4eba9c11703f
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/web/Zend/Memory/Manager.php	Mon Dec 13 18:29:26 2010 +0100
@@ -0,0 +1,463 @@
+<?php
+/**
+ * Zend Framework
+ *
+ * LICENSE
+ *
+ * This source file is subject to the new BSD license that is bundled
+ * with this package in the file LICENSE.txt.
+ * It is also available through the world-wide-web at this URL:
+ * http://framework.zend.com/license/new-bsd
+ * If you did not receive a copy of the license and are unable to
+ * obtain it through the world-wide-web, please send an email
+ * to license@zend.com so we can send you a copy immediately.
+ *
+ * @category   Zend
+ * @package    Zend_Memory
+ * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license    http://framework.zend.com/license/new-bsd     New BSD License
+ * @version    $Id: Manager.php 20096 2010-01-06 02:05:09Z bkarwin $
+ */
+
+/** Zend_Memory_Container_Movable */
+require_once 'Zend/Memory/Container/Movable.php';
+
+/** Zend_Memory_Container_Locked */
+require_once 'Zend/Memory/Container/Locked.php';
+
+/** Zend_Memory_AccessController */
+require_once 'Zend/Memory/AccessController.php';
+
+
+/**
+ * Memory manager
+ *
+ * This class encapsulates memory menagement operations, when PHP works
+ * in limited memory mode.
+ *
+ *
+ * @category   Zend
+ * @package    Zend_Memory
+ * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license    http://framework.zend.com/license/new-bsd     New BSD License
+ */
+class Zend_Memory_Manager
+{
+    /**
+     * Object storage backend
+     *
+     * @var Zend_Cache_Backend_Interface
+     */
+    private $_backend = null;
+
+    /**
+     * Memory grow limit.
+     * Default value is 2/3 of memory_limit php.ini variable
+     * Negative value means no limit
+     *
+     * @var integer
+     */
+    private $_memoryLimit = -1;
+
+    /**
+     * Minimum value size to be swapped.
+     * Default value is 16K
+     * Negative value means that memory objects are never swapped
+     *
+     * @var integer
+     */
+    private $_minSize = 16384;
+
+    /**
+     * Overall size of memory, used by values
+     *
+     * @var integer
+     */
+    private $_memorySize = 0;
+
+    /**
+     * Id for next Zend_Memory object
+     *
+     * @var integer
+     */
+    private $_nextId = 0;
+
+    /**
+     * List of candidates to unload
+     *
+     * It also represents objects access history. Last accessed objects are moved to the end of array
+     *
+     * array(
+     *     <id> => <memory container object>,
+     *     ...
+     *      )
+     *
+     * @var array
+     */
+    private $_unloadCandidates = array();
+
+    /**
+     * List of object sizes.
+     *
+     * This list is used to calculate modification of object sizes
+     *
+     * array( <id> => <size>, ...)
+     *
+     * @var array
+     */
+    private $_sizes = array();
+
+    /**
+     * Last modified object
+     *
+     * It's used to reduce number of calls necessary to trace objects' modifications
+     * Modification is not processed by memory manager until we do not switch to another
+     * object.
+     * So we have to trace only _first_ object modification and do nothing for others
+     *
+     * @var Zend_Memory_Container_Movable
+     */
+    private $_lastModified = null;
+
+    /**
+     * Unique memory manager id
+     *
+     * @var integer
+     */
+    private $_managerId;
+
+    /**
+     * Tags array, used by backend to categorize stored values
+     *
+     * @var array
+     */
+    private $_tags;
+
+    /**
+     * This function is intended to generate unique id, used by memory manager
+     */
+    private function _generateMemManagerId()
+    {
+        /**
+         * @todo !!!
+         * uniqid() php function doesn't really garantee the id to be unique
+         * it should be changed by something else
+         * (Ex. backend interface should be extended to provide this functionality)
+         */
+        $this->_managerId = uniqid('ZendMemManager', true);
+        $this->_tags = array($this->_managerId);
+        $this->_managerId .= '_';
+    }
+
+
+    /**
+     * Memory manager constructor
+     *
+     * If backend is not specified, then memory objects are never swapped
+     *
+     * @param Zend_Cache_Backend $backend
+     * @param array $backendOptions associative array of options for the corresponding backend constructor
+     */
+    public function __construct($backend = null)
+    {
+        if ($backend === null) {
+            return;
+        }
+
+        $this->_backend = $backend;
+        $this->_generateMemManagerId();
+
+        $memoryLimitStr = trim(ini_get('memory_limit'));
+        if ($memoryLimitStr != ''  &&  $memoryLimitStr != -1) {
+            $this->_memoryLimit = (integer)$memoryLimitStr;
+            switch (strtolower($memoryLimitStr[strlen($memoryLimitStr)-1])) {
+                case 'g':
+                    $this->_memoryLimit *= 1024;
+                    // Break intentionally omitted
+                case 'm':
+                    $this->_memoryLimit *= 1024;
+                    // Break intentionally omitted
+                case 'k':
+                    $this->_memoryLimit *= 1024;
+                    break;
+
+                default:
+                    break;
+            }
+
+            $this->_memoryLimit = (int)($this->_memoryLimit*2/3);
+        } // No limit otherwise
+    }
+
+    /**
+     * Object destructor
+     *
+     * Clean up backend storage
+     */
+    public function __destruct()
+    {
+        if ($this->_backend !== null) {
+            $this->_backend->clean(Zend_Cache::CLEANING_MODE_MATCHING_TAG, $this->_tags);
+        }
+    }
+
+    /**
+     * Set memory grow limit
+     *
+     * @param integer $newLimit
+     * @throws Zend_Exception
+     */
+    public function setMemoryLimit($newLimit)
+    {
+        $this->_memoryLimit = $newLimit;
+
+        $this->_swapCheck();
+    }
+
+    /**
+     * Get memory grow limit
+     *
+     * @return integer
+     */
+    public function getMemoryLimit()
+    {
+        return $this->_memoryLimit;
+    }
+
+    /**
+     * Set minimum size of values, which may be swapped
+     *
+     * @param integer $newSize
+     */
+    public function setMinSize($newSize)
+    {
+        $this->_minSize = $newSize;
+    }
+
+    /**
+     * Get minimum size of values, which may be swapped
+     *
+     * @return integer
+     */
+    public function getMinSize()
+    {
+        return $this->_minSize;
+    }
+
+    /**
+     * Create new Zend_Memory value container
+     *
+     * @param string $value
+     * @return Zend_Memory_Container_Interface
+     * @throws Zend_Memory_Exception
+     */
+    public function create($value = '')
+    {
+        return $this->_create($value,  false);
+    }
+
+    /**
+     * Create new Zend_Memory value container, which has value always
+     * locked in memory
+     *
+     * @param string $value
+     * @return Zend_Memory_Container_Interface
+     * @throws Zend_Memory_Exception
+     */
+    public function createLocked($value = '')
+    {
+        return $this->_create($value, true);
+    }
+
+    /**
+     * Create new Zend_Memory object
+     *
+     * @param string $value
+     * @param boolean $locked
+     * @return Zend_Memory_Container_Interface
+     * @throws Zend_Memory_Exception
+     */
+    private function _create($value, $locked)
+    {
+        $id = $this->_nextId++;
+
+        if ($locked  ||  ($this->_backend === null) /* Use only memory locked objects if backend is not specified */) {
+            return new Zend_Memory_Container_Locked($value);
+        }
+
+        // Commit other objects modifications
+        $this->_commit();
+
+        $valueObject = new Zend_Memory_Container_Movable($this, $id, $value);
+
+        // Store last object size as 0
+        $this->_sizes[$id] = 0;
+        // prepare object for next modifications
+        $this->_lastModified = $valueObject;
+
+        return new Zend_Memory_AccessController($valueObject);
+    }
+
+    /**
+     * Unlink value container from memory manager
+     *
+     * Used by Memory container destroy() method
+     *
+     * @internal
+     * @param integer $id
+     * @return Zend_Memory_Container
+     */
+    public function unlink(Zend_Memory_Container_Movable $container, $id)
+    {
+        if ($this->_lastModified === $container) {
+            // Drop all object modifications
+            $this->_lastModified = null;
+            unset($this->_sizes[$id]);
+            return;
+        }
+
+        if (isset($this->_unloadCandidates[$id])) {
+            unset($this->_unloadCandidates[$id]);
+        }
+
+        $this->_memorySize -= $this->_sizes[$id];
+        unset($this->_sizes[$id]);
+    }
+
+    /**
+     * Process value update
+     *
+     * @internal
+     * @param Zend_Memory_Container_Movable $container
+     * @param integer $id
+     */
+    public function processUpdate(Zend_Memory_Container_Movable $container, $id)
+    {
+        /**
+         * This method is automatically invoked by memory container only once per
+         * "modification session", but user may call memory container touch() method
+         * several times depending on used algorithm. So we have to use this check
+         * to optimize this case.
+         */
+        if ($container === $this->_lastModified) {
+            return;
+        }
+
+        // Remove just updated object from list of candidates to unload
+        if( isset($this->_unloadCandidates[$id])) {
+            unset($this->_unloadCandidates[$id]);
+        }
+
+        // Reduce used memory mark
+        $this->_memorySize -= $this->_sizes[$id];
+
+        // Commit changes of previously modified object if necessary
+        $this->_commit();
+
+        $this->_lastModified = $container;
+    }
+
+    /**
+     * Commit modified object and put it back to the loaded objects list
+     */
+    private function _commit()
+    {
+        if (($container = $this->_lastModified) === null) {
+            return;
+        }
+
+        $this->_lastModified = null;
+
+        $id = $container->getId();
+
+        // Calculate new object size and increase used memory size by this value
+        $this->_memorySize += ($this->_sizes[$id] = strlen($container->getRef()));
+
+        if ($this->_sizes[$id] > $this->_minSize) {
+            // Move object to "unload candidates list"
+            $this->_unloadCandidates[$id] = $container;
+        }
+
+        $container->startTrace();
+
+        $this->_swapCheck();
+    }
+
+    /**
+     * Check and swap objects if necessary
+     *
+     * @throws Zend_MemoryException
+     */
+    private function _swapCheck()
+    {
+        if ($this->_memoryLimit < 0  ||  $this->_memorySize < $this->_memoryLimit) {
+            // Memory limit is not reached
+            // Do nothing
+            return;
+        }
+
+        // walk through loaded objects in access history order
+        foreach ($this->_unloadCandidates as $id => $container) {
+            $this->_swap($container, $id);
+            unset($this->_unloadCandidates[$id]);
+
+            if ($this->_memorySize < $this->_memoryLimit) {
+                // We've swapped enough objects
+                return;
+            }
+        }
+
+        require_once 'Zend/Memory/Exception.php';
+        throw new Zend_Memory_Exception('Memory manager can\'t get enough space.');
+    }
+
+
+    /**
+     * Swap object data to disk
+     * Actualy swaps data or only unloads it from memory,
+     * if object is not changed since last swap
+     *
+     * @param Zend_Memory_Container_Movable $container
+     * @param integer $id
+     */
+    private function _swap(Zend_Memory_Container_Movable $container, $id)
+    {
+        if ($container->isLocked()) {
+            return;
+        }
+
+        if (!$container->isSwapped()) {
+            $this->_backend->save($container->getRef(), $this->_managerId . $id, $this->_tags);
+        }
+
+        $this->_memorySize -= $this->_sizes[$id];
+
+        $container->markAsSwapped();
+        $container->unloadValue();
+    }
+
+    /**
+     * Load value from swap file.
+     *
+     * @internal
+     * @param Zend_Memory_Container_Movable $container
+     * @param integer $id
+     */
+    public function load(Zend_Memory_Container_Movable $container, $id)
+    {
+        $value = $this->_backend->load($this->_managerId . $id, true);
+
+        // Try to swap other objects if necessary
+        // (do not include specified object into check)
+        $this->_memorySize += strlen($value);
+        $this->_swapCheck();
+
+        // Add loaded obect to the end of loaded objects list
+        $container->setValue($value);
+
+        if ($this->_sizes[$id] > $this->_minSize) {
+            // Add object to the end of "unload candidates list"
+            $this->_unloadCandidates[$id] = $container;
+        }
+    }
+}