Jamm\Memory\Shm\MultiAccess::get_access_write PHP Method

    public function get_access_write(&$auto_unlocker_reference)
    {
        if ($this->writers_count <= 0) {
            if ($this->readers_count > 0) {
                $this->readers_count = 0;
                $this->release_access_read($auto_unlocker_reference);
            }
            //acquire mutex for writing
            if (!$this->acquire_writers_mutex()) {
                return false;
            }
            //only 1 writer can send message to writers queue, so if in queue more than 1 message - it's somebody's error, and we will fix it now:
            $this->clean_queue(self::writers);
            //tell to readers, that they should wait while we will write
            //this action should be made before writer will wait for readers
            $sent = $this->increment(self::writers);
            //after this command, readers will wait, until we will leave the queue
            if (!$sent) {
                $this->release_writers_mutex();
                return false;
            }
            //but if readers has come before us - wait, until they finish
            if (!$this->wait(self::readers)) {
                $this->decrement(self::writers);
                $this->release_writers_mutex();
                return false;
            }
        }
        $auto_unlocker_reference = new \Jamm\Memory\KeyAutoUnlocker(array($this, 'release_access_write'));
        $this->writers_count++;
        //and now we can write :)
        return true;
    }