| Path : /opt/z-push/backend/ipcsharedmemory/ |
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| Current File : //opt/z-push/backend/ipcsharedmemory/ipcsharedmemoryprovider.php |
<?php
/***********************************************
* File : ipcsharedmemoryprovider.php
* Project : Z-Push
* Descr : IPC Provider for PHP shared memory extension
*
* Created : 20.10.2011
*
* Copyright 2007 - 2016 Zarafa Deutschland GmbH
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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/>.
*
* Consult LICENSE file for details
************************************************/
class IpcSharedMemoryProvider implements IIpcProvider {
private $mutexid;
private $memid;
protected $type;
protected $allocate;
/**
* Constructor
*
* @param int $type
* @param int $allocate
* @param string $class
* @param string $serverKey
*/
public function __construct($type, $allocate, $class, $serverKey) {
$this->type = $type;
$this->allocate = $allocate;
if ($this->initSharedMem())
ZLog::Write(LOGLEVEL_DEBUG, sprintf("%s(): Initialized mutexid %s and memid %s.", $class, $this->mutexid, $this->memid));
}
/**
* Allocates shared memory.
*
* @access private
* @return boolean
*/
private function initSharedMem() {
if (!function_exists('sem_get') || !function_exists('shm_attach') || !function_exists('sem_acquire')|| !function_exists('shm_get_var')) {
ZLog::Write(LOGLEVEL_INFO, "IpcSharedMemoryProvider->initSharedMem(): PHP libraries for the use shared memory are not available. Check the isntalled php packages or use e.g. the memcache IPC provider.");
return false;
}
// Create mutex
$this->mutexid = @sem_get($this->type, 1);
if ($this->mutexid === false) {
ZLog::Write(LOGLEVEL_ERROR, "IpcSharedMemoryProvider->initSharedMem(): could not aquire semaphore");
return false;
}
// Attach shared memory
$this->memid = shm_attach($this->type+10, $this->allocate);
if ($this->memid === false) {
ZLog::Write(LOGLEVEL_ERROR, "IpcSharedMemoryProvider->initSharedMem(): could not attach shared memory");
@sem_remove($this->mutexid);
$this->mutexid = false;
return false;
}
// TODO mem cleanup has to be implemented
//$this->setInitialCleanTime();
return true;
}
/**
* Removes and detaches shared memory.
*
* @access private
* @return boolean
*/
private function removeSharedMem() {
if ((isset($this->mutexid) && $this->mutexid !== false) && (isset($this->memid) && $this->memid !== false)) {
@sem_acquire($this->mutexid);
$memid = $this->memid;
$this->memid = false;
@sem_release($this->mutexid);
@sem_remove($this->mutexid);
@shm_remove($memid);
@shm_detach($memid);
$this->mutexid = false;
return true;
}
return false;
}
/**
* Reinitializes the IPC data by removing, detaching and re-allocating it.
*
* @access public
* @return boolean
*/
public function ReInitIPC() {
return ($this->removeSharedMem() && $this->initSharedMem());
}
/**
* Cleans up the IPC data block.
*
* @access public
* @return boolean
*/
public function Clean() {
$stat = false;
// exclusive block
if ($this->BlockMutex()) {
$cleanuptime = ($this->HasData(1)) ? $this->GetData(1) : false;
// TODO implement Shared Memory cleanup
$this->ReleaseMutex();
}
// end exclusive block
return $stat;
}
/**
* Indicates if the IPC is active.
*
* @access public
* @return boolean
*/
public function IsActive() {
return ((isset($this->mutexid) && $this->mutexid !== false) && (isset($this->memid) && $this->memid !== false));
}
/**
* Blocks the class mutex.
* Method blocks until mutex is available!
* ATTENTION: make sure that you *always* release a blocked mutex!
*
* @access public
* @return boolean
*/
public function BlockMutex() {
if ((isset($this->mutexid) && $this->mutexid !== false) && (isset($this->memid) && $this->memid !== false))
return @sem_acquire($this->mutexid);
return false;
}
/**
* Releases the class mutex.
* After the release other processes are able to block the mutex themselves.
*
* @access public
* @return boolean
*/
public function ReleaseMutex() {
if ((isset($this->mutexid) && $this->mutexid !== false) && (isset($this->memid) && $this->memid !== false))
return @sem_release($this->mutexid);
return false;
}
/**
* Indicates if the requested variable is available in IPC data.
*
* @param int $id int indicating the variable
*
* @access public
* @return boolean
*/
public function HasData($id = 2) {
if ((isset($this->mutexid) && $this->mutexid !== false) && (isset($this->memid) && $this->memid !== false)) {
if (function_exists("shm_has_var"))
return @shm_has_var($this->memid, $id);
else {
$some = $this->GetData($id);
return isset($some);
}
}
return false;
}
/**
* Returns the requested variable from IPC data.
*
* @param int $id int indicating the variable
*
* @access public
* @return mixed
*/
public function GetData($id = 2) {
if ((isset($this->mutexid) && $this->mutexid !== false) && (isset($this->memid) && $this->memid !== false))
return @shm_get_var($this->memid, $id);
return ;
}
/**
* Writes the transmitted variable to IPC data.
* Subclasses may never use an id < 2!
*
* @param mixed $data data which should be saved into IPC data
* @param int $id int indicating the variable (bigger than 2!)
*
* @access public
* @return boolean
*/
public function SetData($data, $id = 2) {
if ((isset($this->mutexid) && $this->mutexid !== false) && (isset($this->memid) && $this->memid !== false))
return @shm_put_var($this->memid, $id, $data);
return false;
}
/**
* Sets the time when the shared memory block was created.
*
* @access private
* @return boolean
*/
private function setInitialCleanTime() {
$stat = false;
// exclusive block
if ($this->BlockMutex()) {
if ($this->HasData(1) == false)
$stat = $this->SetData(time(), 1);
$this->ReleaseMutex();
}
// end exclusive block
return $stat;
}
}