We are using Poco in our project and we've found 3 cases where we are embarrassed with poco and its pointer gesture.
In most of cases when you call a mathod of a poco class, it take in parameter a Poco::SharedPtr<> but sometimes, it take a pointer in parameter. After it take ownership of the pointer creating a SharedPtr<> inside its class.
Sometime we would like to provide a class to poco keeping the ownership of it. For example to prevent it from being detroy at the end of each call.
For example, this class use the poco::TaskManager class to run a task. But we must be very careful about this because the ownership of the object we have created belongs to poco::TaskManager.
CMyClass()
{
m_xplTask = new CXplServiceTask(...);
//task manager take the ownership !! (why ??)
m_taskManager.start(m_xplTask);
}
~CMyClass()
{
//do not delete m_xplTask; because owned by Poco::TaskManager ;-(
}
Another example :
We use a CRestRequestHandler pointer named p in a locally context to provide it to the HTTPServer. but we must create it at each call ! If we could we prefer to make a Poco::ShaaredPtr in member an simply return it. But if we do that with this pointer we can't know if the pointer is alive or not.
Poco::Net::HTTPRequestHandler* CHttpRequestHandlerFactory::createRequestHandler(const Poco::Net::HTTPServerRequest& request)
{
//do not keep pointers in shared_ptr or somewhere else, because poco take ownership ;-(
if (boost::istarts_with(request.getURI(), m_webSocketKeyword))
return new CWebSocketRequestHandler(m_notificationCenter);
else if (boost::istarts_with(request.getURI(), m_restKeywordBase))
{
CRestRequestHandler * p = new CRestRequestHandler(m_restKeywordBase);
//do some very long init
std::vector< boost::shared_ptr<web::rest::service::IRestService> >::iterator i;
for (i = m_restService.begin(); i != m_restService.end(); ++i)
p->registerRestService(*i);
p->initialize();
return p;
}
else
{
CWebsiteRequestHandler * p = new CWebsiteRequestHandler(m_configDocRoot);
std::map<std::string, std::string>::iterator i;
for (i = m_alias.begin(); i != m_alias.end();++i)
p->configureAlias(i->first, i->second);
return p;
}
}
the other case concern the TCPServerConnectionFactory already post in stack overflow: Can't use Poco TCPServer and TCPServerConnectionFactory
Why some methods always take ownership ? Is it not possible to have a signature to provide a SharedPtr<> instead ? I think there is not many modification into poco lib to do that.
Any explanation ?
