Client cannot be deleted properly about simple-websocket-server

[eidheim]

Might be better if you create a pull request, since you got the code already to test it and see if you get rid of the warning:)

[eidheim]

Seems a bit strange though to be needing to create a destructor for this, since destructors should generally not be created manually if they are not needed.

[pp23]

I will create a pull request later on. The warning (and the resulting segfault during execution) occurs in a test code of a bigger project. But I can easily create a simple separated server/client code for an example.

I have already searched a bit on the web and found this useful answer on stackoverflow: http://stackoverflow.com/a/827203/1926463

[eidheim]

From http://programmers.stackexchange.com/questions/284561/when-not-to-use-virtual-destructors: "The reason is subclassing + use of polymorphism. A virtual destructor is required only if a dynamic resolution is needed, that is a reference/pointer/whatever to the master class may actually refer to an instance of a subclass". If your pointer is always of type SocketClient for instance, the virtual destructor is not needed if I understand it correctly, the problem is if you are in need of dynamic casting (for instance your pointer is of type SocketClientBase and you want to be able cast it to either SocketClient or SocketClient). Or am I wrong?

[pp23]

The code below is crashing with the following stack trace:

0   malloc_consolidate      4157    0x7ffff67b88f3  
1   _int_free       4057    0x7ffff67b956d  
2   __gnu_cxx::new_allocator<std::_Sp_counted_ptr_inplace<SimpleWeb::SocketClientBase<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp>>>::SendStream, std::allocator<SimpleWeb::SocketClientBase<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp>>>::SendStream>, (__gnu_cxx::_Lock_policy)2>>::deallocate    new_allocator.h 110 0x42b08c    
3   std::allocator_traits<std::allocator<std::_Sp_counted_ptr_inplace<SimpleWeb::SocketClientBase<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp>>>::SendStream, std::allocator<SimpleWeb::SocketClientBase<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp>>>::SendStream>, (__gnu_cxx::_Lock_policy)2>>>::deallocate   alloc_traits.h  377 0x4295b1    
4   std::_Sp_counted_ptr_inplace<SimpleWeb::SocketClientBase<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp>>>::SendStream, std::allocator<SimpleWeb::SocketClientBase<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp>>>::SendStream>, (__gnu_cxx::_Lock_policy)2>::_M_destroy  shared_ptr_base.h   417 0x43242a    
5   std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release   shared_ptr_base.h   161 0x41a022    
6   std::__shared_count<(__gnu_cxx::_Lock_policy)2>::~__shared_count    shared_ptr_base.h   546 0x416c19    
7   std::__shared_ptr<SimpleWeb::SocketClientBase<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp>>>::SendStream, (__gnu_cxx::_Lock_policy)2>::~__shared_ptr shared_ptr_base.h   781 0x41459c    
8   std::shared_ptr<SimpleWeb::SocketClientBase<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp>>>::SendStream>::~shared_ptr shared_ptr.h    93  0x4145b6    
9   SimpleWeb::SocketClientBase<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp>>>::send(std::shared_ptr<SimpleWeb::SocketClientBase<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp>>>::SendStream>, std::function<void (boost::system::error_code const&)> const&, unsigned char)::{lambda()#1}::~function()    client_ws.hpp   170 0x418dda    
10  boost::asio::detail::completion_handler<SimpleWeb::SocketClientBase<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp>>>::send(std::shared_ptr<SimpleWeb::SocketClientBase<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp>>>::SendStream>, std::function<void (boost::system::error_code const&)> const&, unsigned char)::{lambda()#1}>::do_complete(boost::asio::detail::task_io_service*, boost::asio::detail::task_io_service_operation*, boost::system::error_code const&, unsigned long)  completion_handler.hpp  59  0x427775    
11  boost::asio::detail::task_io_service_operation::destroy task_io_service_operation.hpp   43  0x40dbba    
12  boost::asio::detail::op_queue_access::destroy<boost::asio::detail::task_io_service_operation>   op_queue.hpp    47  0x41985e    
13  boost::asio::detail::op_queue<boost::asio::detail::task_io_service_operation>::~op_queue    op_queue.hpp    81  0x4150ce    
14  boost::asio::detail::strand_service::shutdown_service   strand_service.ipp  66  0x41353b    
15  boost::asio::detail::service_registry::~service_registry    service_registry.ipp    37  0x40d783    
16  boost::asio::io_service::~io_service    io_service.ipp  53  0x410551    
17  SimpleWeb::SocketClientBase<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp>>>::~SocketClientBase    client_ws.hpp   19  0x413be3    
18  SimpleWeb::SocketClient<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp>>>::~SocketClient    client_ws.hpp   443 0x41457d        

typedef SimpleWeb::SocketClient<SimpleWeb::WS> WsClient;

static const size_t clientCount = 250;

BOOST_AUTO_TEST_CASE(OpenTest) {
    std::atomic<int> openedClients(0);
    WsClient *client[clientCount];
    std::thread t[clientCount];
    for(size_t i = 0; i < clientCount; ++i) {
        client[i] = new WsClient("localhost:8080/a");
        client[i]->onopen = [&client,i,&openedClients]() {
            client[i]->send_close(0);
            client[i]->stop();
            ++openedClients;
        };
    }
    for(size_t i = 0; i < clientCount; ++i) {
        WsClient* c = client[i];
        BOOST_REQUIRE_MESSAGE(c != nullptr, "Client is null: " + std::to_string(i));
        if(c != nullptr) {
            t[i] = std::thread([c](){ try {
                    c->start();
                }catch(std::invalid_argument e){
                    std::cerr << "Exception: " << e.what() << std::endl;
                }
            });
        }
    }

    for(size_t i = 0; i < clientCount; ++i) {
        t[i].join();
    }

    for(size_t i = 0; i < clientCount; ++i) {
        delete client[i];                                    //SegFault
    }

    BOOST_TEST(openedClients == clientCount);
}

[eidheim]

I see now that http://www.boost.org/doc/libs/1_60_0/doc/html/boost_asio/reference/io_service/stop.html is not blocking, so the destructor (#28) should maybe wait until http://www.boost.org/doc/libs/1_60_0/doc/html/boost_asio/reference/io_service/stopped.html is true instead. I'll have a look at this in a day or two. At least you have a working version in #28.

Edit: disregard this message too, your solution seems like the best one so far.