/**
* Calls the corresponding function in the block and executes the data retrieval function.
* @return \SimpleXMLElement The XML data tree
*/
public final function callMemcacheBlock()
{
$callback = $this->getCallback();
$db = $this->getDatabase();
$mem = new \System\Cache\Memcache\Memcache();
$xml = null;
if ($mem->keyExists($this->key)) {
$xmlString = $mem->get($this->key);
if ($xmlString) {
//suppress warning here in case of malformed xml
$xml = @simplexml_load_string($xmlString);
if ($xml instanceof \SimpleXMLElement) {
return $xml;
} else {
$errorLogger = \System\Log\ErrorLogger::getInstance();
$errorLogger->out('[MemcacheBlock] Could not read memcache key ' . $this->key . ' as XML. Regenerating.', \System\Log\LoggerLevel::LEVEL_WARNING);
}
}
}
if (is_callable($callback)) {
$xml = call_user_func($callback, $this);
$mem->store($this->key, $xml->asXML(), $this->timeout);
} else {
throw new \System\Error\Exception\InvalidMethodException('The given callback cannot be called. Does it exist and is it public?');
}
return $xml;
}
/**
* Calls the corresponding function in the block and checks for LUT availability.
* @return \SimpleXMLElement The XML data tree
*/
public final function callStaticBlock()
{
$db = $this->getDatabase();
$xml = '';
$filename = null;
$returnVal = \System\Cache\LUTCache\LUTCache::retrieve($db, $this->getLUTKey(), $filename);
switch ($returnVal) {
case \System\Cache\LUTCache\Status::CACHE_GENERATING:
$totalWaitTime = 0;
while (($returnVal = \System\Cache\LUTCache\LUTCache::retrieve($db, $this->getLUTKey(), $filename)) == \System\Cache\LUTCache\Status::CACHE_GENERATING) {
//we wait before polling the system again
usleep(self::CACHE_GENERATE_POLL_TIME);
$totalWaitTime += self::CACHE_GENERATE_POLL_TIME;
if ($totalWaitTime >= self::CACHE_GENERATE_WAIT_THRESHOLD) {
throw new \System\Error\Exception\LUTCacheTimeoutException('The generation timeout is exceeded for block: ' . $this->getLUTKey());
}
}
if ($returnVal != \System\Cache\LUTCache\Status::CACHE_HIT) {
throw new \Exception('Invalid LUT returnvalue given after generation: ' . $returnVal);
}
//we do a fallthrough after we are done generating
//we do a fallthrough after we are done generating
case \System\Cache\LUTCache\Status::CACHE_HIT:
//get stuff
$fullFile = self::getWritablePath($filename) . $filename;
if (file_exists($fullFile)) {
//suppress warnings here in case of malformed xml
if ($xml = @simplexml_load_file($fullFile)) {
break;
} else {
$errorLogger = \System\Log\ErrorLogger::getInstance();
$errorLogger->out('[StaticBlock] Could not read ' . $fullFile . ' as XML. Regenerating.', \System\Log\LoggerLevel::LEVEL_WARNING);
}
}
//if the file does not exist, we do a fallthrough to the generation
//if the file does not exist, we do a fallthrough to the generation
case \System\Cache\LUTCache\Status::CACHE_MISS:
case \System\Cache\LUTCache\Status::CACHE_INVALIDATED:
//set to currently generating
\System\Cache\LUTCache\LUTCache::setToGenerate($db, $this->getLUTKey());
//get the XML
$xml = $this->callBlock($this);
//store the xml to a file and add the file to the LUT
$cacheFile = self::FILENAME_PREFIX . uniqid() . self::FILENAME_EXTENSION;
$fullFile = self::getWritablePath($cacheFile) . $cacheFile;
$xml->asXML($fullFile);
\System\Cache\LUTCache\LUTCache::store($db, $this->getLUTKey(), $cacheFile);
break;
default:
throw new \Exception('Invalid LUT returnvalue given: ' . $returnVal);
}
return $xml;
}
