/**
* This function wraps shmop_open with a Timer and an amount of tries to capture
* shmop_open/release warnings which then would not provide further access to the
* shared memory segment.
* Additionally using synchronized threads would require PECL pthreads >= 2.0.0,
* which we will not include to separate accesses from each other.
* @param $key segment key passed onto shmop_open
* @param $mode mode the segment should be opened with
* @param $perms the permissions for the segment
* @param $size the size of the segment
* @param $tries number of tries to attach before throwing an exception
* @param $timeout timeout in seconds for each try
* @return shared memory segment id
* @throws TimerException
* @throws SegmentException
* @bug 2016-00001 shmop_*, sem_* failures
* @see Timer
*/
private function open($key = null, $mode = "w", $perms = 0600, $size = 1024, $timeout = 2, $tries = 3)
{
// set and start the timer
$timer = null;
if (strncmp(gettype($timeout), "integer", 7) == 0 && $timeout > 0) {
$timer = new Timer($timeout);
}
// run the timer
if ($timer !== null) {
$timer->start();
} else {
$this->log(__METHOD__ . ": %.", array(new TimerException("creation failed")));
throw new TimerException("creation failed");
}
// then try to attach to the segment
$sid = false;
$try = 1;
while ($timer !== null && $key !== null && $sid === false && $try <= $tries) {
// try to create or attach to the segment
$sid = @shmop_open($key, $mode, $perms, $size);
if ($timer->get() === 0 && $timer->get_timed_out()) {
$this->log(__METHOD__ . ": Attaching segment. Try #%. Timer timed out.", array($try));
$try++;
$timer->start();
}
}
// throw some exceptions if something failed
if ($sid === false) {
$this->log(__METHOD__ . ": %", array(new SegmentException("creation/attaching failed", 5)));
throw new SegmentException("creation/attaching failed", 5);
}
// otherwise return the shm segment id to access the segment
return $sid;
}
/**
* Release a semaphore when th work is done.
* DO NOT forget to call this when running sem_acquire without
* $nowait flag set to true.
* @throws TimerException
* @throws SemaphoreException
* @return true if the semaphore was release otherwise false
*/
public function release($timeout = 30, $tries = 3)
{
// set and start the timer
$timer = null;
if (strncmp(gettype($timeout), "integer", 7) == 0 && $timeout > 0) {
$timer = new Timer($timeout);
}
if ($timer === null) {
$this->log(__METHOD__ . ": %.", array(new TimerException("creation failed")));
throw new TimerException("creation failed");
}
$timer->start();
// now try to acquire a semaphore
$released = false;
$try = 1;
while (!is_null($this->semaphore->get_sem_res()) && $released === false && $timer !== null && $try <= $this->semaphore_max_try) {
// use sem_acquire with $nowait flag to append a timer
$released = @sem_release($this->semaphore->get_sem_res());
// retart the timer
if ($timer->get() == 0 && $timer->get_timed_out()) {
$this->log(__METHOD__ . ": Releasing. Try #%. Timer timed out.", array($try));
$try++;
$timer->start();
}
}
// if releasing failed
if ($released === false) {
$this->log(__METHOD__ . ": %.", array(new SemaphoreException("release failed", 1)));
throw new SemaphoreException("release failed", 1);
}
return $released;
}
// the include path like 'Log.php'
require_once "../../core/autoloader.class.php";
$al = new AutoLoader(false, "../..");
$al->expand(".test.class.php,.interface.php,.php");
$al->load();
// create a filelogger for this example
$fl = new FileLogger("shmhandler.php");
$fl->logge("%", array($al));
$fl->logge("%", array($fl));
// use a timer to control an action
$timeout = 2;
$tries = 3;
// set and start the timer
$timer = null;
if (strncmp(gettype($timeout), "integer", 7) == 0 && $timeout > 0) {
$timer = new Timer($timeout);
}
if ($timer === null) {
$fl->logge(__METHOD__ . ": %.", array(new TimerException("creation failed")));
throw new TimerException("creation failed");
}
$timer->start();
// now try to acquire a semaphore
$actiondone = false;
$try = 1;
while ($actiondone === false && $timer !== null && $try <= $tries) {
// run an action
$actiondone = false;
// retart the timer
if ($timer->get() == 0 && $timer->get_timed_out()) {
$fl->logge(__METHOD__ . ": Try #%. Timer timed out.", array($try));