stk-code_catmod/src/online/http_manager.cpp

//
//  SuperTuxKart - a fun racing game with go-kart
//  Copyright (C) 2010 Lucas Baudin
//                2011 Joerg Henrichs
//                2013 Glenn De Jonghe
//
//  This program is free software; you can redistribute it and/or
//  modify it under the terms of the GNU General Public License
//  as published by the Free Software Foundation; either version 3
//  of the License, or (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program; if not, write to the Free Software
//  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

#include "online/http_manager.hpp"

#include "online/current_user.hpp"
#include "states_screens/state_manager.hpp"

#include <iostream>
#include <stdio.h>
#include <memory.h>
#include <errno.h>

#if defined(WIN32) && !defined(__CYGWIN__)
#  include <windows.h>
#else
#  include <sys/time.h>
#  include <math.h>
#endif

using namespace Online;

namespace Online{
    #define MENU_POLLING_INTERVAL 10.0f
    #define GAME_POLLING_INTERVAL 15.0f

    static HTTPManager * http_singleton = NULL;

    HTTPManager* HTTPManager::get()
    {
        if (http_singleton == NULL)
        {
            http_singleton = new HTTPManager();
        }
        return http_singleton;
    }   // get

    void HTTPManager::deallocate()
    {
        if (http_singleton != NULL)
        {
            delete http_singleton;
            http_singleton = NULL;
        }
    }   // deallocate

    bool HTTPManager::isRunning()
    {
        return http_singleton != NULL;
    }


    HTTPManager::HTTPManager(){
        curl_global_init(CURL_GLOBAL_DEFAULT);
        pthread_cond_init(&m_cond_request, NULL);
        m_abort.setAtomic(false);
        m_time_since_poll = MENU_POLLING_INTERVAL * 0.9;
    }

    // ============================================================================
    HTTPManager::~HTTPManager(){
        m_thread_id.lock();
        pthread_join(*m_thread_id.getData(), NULL);
        delete m_thread_id.getData();
        m_thread_id.unlock();
        pthread_cond_destroy(&m_cond_request);
        curl_global_cleanup();
    }


    // ---------------------------------------------------------------------------
    /** Start the actual network thread. This can not be done as part of
     *  the constructor, since the assignment to the global network_http
     *  variable has not been assigned at that stage, and the thread might
     *  use network_http - a very subtle race condition. So the thread can
     *  only be started after the assignment (in main) has been done.
     */
    void HTTPManager::startNetworkThread()
    {
        pthread_attr_t  attr;
        pthread_attr_init(&attr);
        pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
        // Should be the default, but just in case:
        pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
        //pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);

        m_thread_id.setAtomic(new pthread_t());
        int error = pthread_create(m_thread_id.getData(), &attr,
                                   &HTTPManager::mainLoop, this);
        if(error)
        {
            m_thread_id.lock();
            delete m_thread_id.getData();
            m_thread_id.unlock();
            m_thread_id.setAtomic(0);
            Log::error("HTTP Manager", "Could not create thread, error=%d.\n", errno);
        }
        pthread_attr_destroy(&attr);
        CurrentUser::get()->requestSavedSession();
    }   // startNetworkThread


    // ---------------------------------------------------------------------------
    /** This function inserts a high priority request to quit into the request
     *  queue of the network thead, and also aborts any ongoing download.
     *  Separating this allows more time for the thread to finish cleanly,
     *  before it gets cancelled in the destructor.
     */
    void HTTPManager::stopNetworkThread()
    {
        // If a download should be active (which means it was cancelled by the
        // user, in which case it will still be ongoing in the background)
        // we can't get the mutex, and would have to wait for a timeout,
        // and we couldn't finish STK. This way we request an abort of
        // a download, which mean we can get the mutex and ask the service
        // thread here to cancel properly.
        //cancelAllDownloads(); FIXME if used this way it also cancels the client-quit action
        CurrentUser::get()->onSTKQuit();
        addRequest(new Request(true, HTTP_MAX_PRIORITY, Request::RT_QUIT));
    }   // stopNetworkThread


    // ----------------------------------------------------------------------------
    /** Signals to the progress function to request any ongoing download to be
     *  cancelled. This function can also be called if there is actually no
     *  download atm. The function progressDownload checks m_abort and will
     *  return a non-zero value which causes libcurl to abort. */
    void HTTPManager::cancelAllDownloads()
    {
        m_abort.setAtomic(true);
        // FIXME doesn't get called at the moment. When using this again, 
        // be sure that HTTP_MAX_PRIORITY requests still get executed.
    }   // cancelAllDownloads


    // ----------------------------------------------------------------------------
    /** Inserts a request into the queue of all requests. The request will be
     *  sorted by priority.
     *  \param request The pointer to the new request to insert.
     */
    void HTTPManager::addRequest(Request *request)
    {
        assert(request->isAllowedToAdd());
        request->setBusy();
        m_request_queue.lock();
        m_request_queue.getData().push(request);
        // Wake up the network http thread
        pthread_cond_signal(&m_cond_request);
        m_request_queue.unlock();
    }   // addRequest


    // ----------------------------------------------------------------------------
    /** Immediately performs a request synchronously
     *  \param request The pointer to the request to execute.
     */
    void HTTPManager::synchronousRequest(Request *request)
    {
        assert(request->isAllowedToAdd());
        request->setBusy();
        request->execute();
        request->callback();
        request->setDone();
    }   // synchronousRequest

    // ---------------------------------------------------------------------------
    /** The actual main loop, which is started as a separate thread from the
     *  constructor. After testing for a new server, fetching news, the list
     *  of packages to download, it will wait for commands to be issued.
     *  \param obj: A pointer to this object, passed on by pthread_create
     */
    void *HTTPManager::mainLoop(void *obj)
    {
        HTTPManager *me = (HTTPManager*) obj;

        pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);

        me->m_current_request = NULL;
        me->m_request_queue.lock();
        while(  me->m_request_queue.getData().empty() || me->m_request_queue.getData().top()->getType() != Request::RT_QUIT)
        {
            bool empty = me->m_request_queue.getData().empty();
            // Wait in cond_wait for a request to arrive. The 'while' is necessary
            // since "spurious wakeups from the pthread_cond_wait ... may occur"
            // (pthread_cond_wait man page)!
            while(empty)
            {
                pthread_cond_wait(&me->m_cond_request, me->m_request_queue.getMutex());
                empty = me->m_request_queue.getData().empty();
            }
            me->m_current_request = me->m_request_queue.getData().top();
            me->m_request_queue.getData().pop();
            me->m_request_queue.unlock();
            me->m_current_request->execute();
            me->addResult(me->m_current_request);
            me->m_request_queue.lock();
        }   // while

        // At this stage we have the lock for m_request_queue
        while(!me->m_request_queue.getData().empty())
        {
            Online::Request * request = me->m_request_queue.getData().top();
            me->m_request_queue.getData().pop();
            // Manage memory can be ignored here, all requests
            // need to be freed.
            delete request;
        }
        me->m_request_queue.unlock();
        pthread_exit(NULL);
        return 0;
    }   // mainLoop

    // ----------------------------------------------------------------------------
    /** Inserts a request into the queue of results.
     *  \param request The pointer to the request to insert.
     */
    void HTTPManager::addResult(Online::Request *request)
    {
        assert(request->isBusy());
        m_result_queue.lock();
        m_result_queue.getData().push(request);
        m_result_queue.unlock();
    }

    // ----------------------------------------------------------------------------
    /**
     * Takes a request out of the result queue, if any is present.
     * Calls the callback method of the request and takes care of memory management if necessary.
     */
    void HTTPManager::handleResultQueue()
    {
        Request * request = NULL;
        m_result_queue.lock();
        if(!m_result_queue.getData().empty())
        {
            request = m_result_queue.getData().front();
            m_result_queue.getData().pop();
        }
        m_result_queue.unlock();
        if(request != NULL)
        {
            request->callback();
            if(request->manageMemory())
            {
                delete request;
                request = NULL;
            }
            else
                request->setDone();
        }
    }

    // ----------------------------------------------------------------------------
    /**
     * Should be called every frame and takes care of processing the result queue
     * and polling the database server if a user is signed in.
     */
    void HTTPManager::update(float dt){
        handleResultQueue();

        //Database polling starts here, only needed for registered users
        if(!CurrentUser::get()->isRegisteredUser())
            return;

        m_time_since_poll += dt;
        float interval = GAME_POLLING_INTERVAL;
        if (StateManager::get()->getGameState() == GUIEngine::MENU)
                interval = MENU_POLLING_INTERVAL;
        if(m_time_since_poll > interval)
        {
            m_time_since_poll = 0;
            CurrentUser::get()->requestPoll();
        }

    }
} // namespace Online