This change fixes a shutdown crash occuring when using an
external io_service to drive a websocketpp server. The crash
itself is reproduced by the following code:
```
int main(int argc, const char * argv[])
{
boost::asio::io_service ioService;
std::unique_ptr<boost::asio::io_service::work> ioServiceWork(new boost::asio::io_service::work(ioService));
std::thread ioServiceThread(boost::bind(&boost::asio::io_service::run, &ioService));
{
auto server = std::unique_ptr<websocketpp::server<websocketpp::config::asio>>(new websocketpp::server<websocketpp::config::asio>());
server->init_asio(&ioService);
server->listen(0);
server->start_accept();
server->stop();
}
ioServiceWork.reset();
ioService.stop();
ioServiceThread.join();
return 0;
}
```
The cause of the crash is a dangling pointer to alog or elog objects in endpoints.
This is mitigated by storing logging objects as shared_ptrs. This ensures that
they are kept alive and able to log even if their owning structures have already
been deallocated.
Peter Thorson
Alex Korotkin
Jupp Müller
Peter Thorson