UEventsManager.cpp

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/*
*  utilite is a cross-platform library with
*  useful utilities for fast and small developing.
*  Copyright (C) 2010  Mathieu Labbe
*
*  utilite is free library: you can redistribute it and/or modify
*  it under the terms of the GNU Lesser General Public License as published by
*  the Free Software Foundation, either version 3 of the License, or
*  (at your option) any later version.
*
*  utilite 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 Lesser General Public License for more details.
*
*  You should have received a copy of the GNU Lesser General Public License
*  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "rtabmap/utilite/UEventsManager.h"
#include "rtabmap/utilite/UEvent.h"
#include <list>
#include "rtabmap/utilite/UStl.h"

UEventsManager* UEventsManager::instance_ = 0;
UDestroyer<UEventsManager> UEventsManager::destroyer_;

void UEventsManager::addHandler(UEventsHandler* handler)
{
        if(!handler)
        {
                UERROR("Handler is null!");
                return;
        }
        else
        {
                UEventsManager::getInstance()->_addHandler(handler);
        }
}

void UEventsManager::removeHandler(UEventsHandler* handler)
{
        if(!handler)
        {
                UERROR("Handler is null!");
                return;
        }
        else
        {
                UEventsManager::getInstance()->_removeHandler(handler);
        }
}

void UEventsManager::post(UEvent * event, bool async, const UEventsSender * sender)
{
        if(!event)
        {
                UERROR("Event is null!");
                return;
        }
        else
        {
                UEventsManager::getInstance()->_postEvent(event, async, sender);
        }
}

void UEventsManager::createPipe(
                const UEventsSender * sender,
                const UEventsHandler * receiver,
                const std::string & eventName)
{
        if(!sender || !receiver)
        {
                UERROR("Sender and/or receiver is null!");
                return;
        }
        else
        {
                UEventsManager::getInstance()->_createPipe(sender, receiver, eventName);
        }
}

void UEventsManager::removePipe(
                const UEventsSender * sender,
                const UEventsHandler * receiver,
                const std::string & eventName)
{
        if(!sender || !receiver)
        {
                UERROR("Sender and/or receiver is null!");
                return;
        }
        else
        {
                UEventsManager::getInstance()->_removePipe(sender, receiver, eventName);
        }
}

void UEventsManager::removeAllPipes(const UEventsSender * sender)
{
        if(!sender)
        {
                UERROR("Sender is null!");
                return;
        }
        else
        {
                UEventsManager::getInstance()->_removeAllPipes(sender);
        }
}

void UEventsManager::removeNullPipes(const UEventsSender * sender)
{
        if(!sender)
        {
                UERROR("Sender is null!");
                return;
        }
        else
        {
                UEventsManager::getInstance()->_removeNullPipes(sender);
        }
}

UEventsManager* UEventsManager::getInstance()
{
    if(!instance_)
    {
        instance_ = new UEventsManager();
        destroyer_.setDoomed(instance_);
        instance_->start(); // Start the thread
    }
    return instance_;
}

UEventsManager::UEventsManager()
{
}

UEventsManager::~UEventsManager()
{
        join(true);

    // Free memory
    for(std::list<std::pair<UEvent*, const UEventsSender*> >::iterator it=events_.begin(); it!=events_.end(); ++it)
    {
        delete it->first;
    }
    events_.clear();

    handlers_.clear();

    instance_ = 0;
}

void UEventsManager::mainLoop()
{
    postEventSem_.acquire();
    if(!this->isKilled())
    {
                dispatchEvents();
    }
}

void UEventsManager::mainLoopKill()
{
    postEventSem_.release();
}

void UEventsManager::dispatchEvents()
{
    if(events_.size() == 0)
    {
        return;
    }

    std::list<std::pair<UEvent*, const UEventsSender*> >::iterator it;
    std::list<std::pair<UEvent*, const UEventsSender*> > eventsBuf;

    // Copy events in a buffer :
    // Other threads can post events 
    // while events are handled.
    eventsMutex_.lock();
    {
        eventsBuf = events_;
        events_.clear();
    }
    eventsMutex_.unlock();

        // Past events to handlers
        for(it=eventsBuf.begin(); it!=eventsBuf.end(); ++it)
        {
                dispatchEvent(it->first, it->second);
                delete it->first;
        }
    eventsBuf.clear();
}

void UEventsManager::dispatchEvent(UEvent * event, const UEventsSender * sender)
{
        std::list<UEventsHandler*> handlers;

        // Verify if there are pipes with the sender for his type of event
        if(sender)
        {
                handlers = getPipes(sender, event->getClassName());
        }

        handlersMutex_.lock();
        if(handlers.size() == 0)
        {
                //No pipes, send to all handlers
                handlers = handlers_;
        }

        for(std::list<UEventsHandler*>::iterator it=handlers.begin(); it!=handlers.end(); ++it)
        {
                // Check if the handler is still in the
                // handlers_ list (may be changed if addHandler() or
                // removeHandler() is called in EventsHandler::handleEvent())
                if(std::find(handlers_.begin(), handlers_.end(), *it) != handlers_.end())
                {
                        UEventsHandler * handler = *it;
                        handlersMutex_.unlock();

                        // Don't process event if the handler is the same as the sender
                        if(handler != sender)
                        {
                                // To be able to add/remove an handler in a handleEvent call (without a deadlock)
                                // @see _addHandler(), _removeHandler()
                                handler->handleEvent(event);
                        }

                        handlersMutex_.lock();
                }
        }
        handlersMutex_.unlock();
}

void UEventsManager::_addHandler(UEventsHandler* handler)
{
    if(!this->isKilled())
    {
        handlersMutex_.lock();
        {
                //make sure it is not already in the list
                bool handlerFound = false;
                for(std::list<UEventsHandler*>::iterator it=handlers_.begin(); it!=handlers_.end(); ++it)
                {
                        if(*it == handler)
                        {
                                handlerFound = true;
                        }
                }
                if(!handlerFound)
                {
                        handlers_.push_back(handler);
                }
        }
        handlersMutex_.unlock();
    }
}

void UEventsManager::_removeHandler(UEventsHandler* handler)
{
    if(!this->isKilled())
    {
        handlersMutex_.lock();
        {
            for (std::list<UEventsHandler*>::iterator it = handlers_.begin(); it!=handlers_.end(); ++it)
            {
                if(*it == handler)
                {
                    handlers_.erase(it);
                    break;
                }
            }
        }
        handlersMutex_.unlock();

        pipesMutex_.lock();
        {
                for(std::list<Pipe>::iterator iter=pipes_.begin(); iter!= pipes_.end(); ++iter)
                        {
                                if(iter->receiver_ == handler)
                                {
                                        iter->receiver_ = 0; // set to null
                                }
                        }
        }
        pipesMutex_.unlock();
    }
}

void UEventsManager::_postEvent(UEvent * event, bool async, const UEventsSender * sender)
{
    if(!this->isKilled())
    {
        if(async)
        {
                        eventsMutex_.lock();
                        {
                                events_.push_back(std::make_pair(event, sender));
                        }
                        eventsMutex_.unlock();

                        // Signal the EventsManager that an Event is added
                        postEventSem_.release();
        }
        else
        {
                dispatchEvent(event, sender);
                delete event;
        }
    }
    else
    {
        delete event;
    }
}

std::list<UEventsHandler*> UEventsManager::getPipes(
                const UEventsSender * sender,
                const std::string & eventName)
{
        std::list<UEventsHandler*> pipes;
        pipesMutex_.lock();

        for(std::list<Pipe>::iterator iter=pipes_.begin(); iter!= pipes_.end(); ++iter)
        {
                if(iter->sender_ == sender && iter->eventName_.compare(eventName) == 0)
                {
                        bool added = false;
                        if(iter->receiver_)
                        {
                                handlersMutex_.lock();
                                for(std::list<UEventsHandler*>::iterator jter=handlers_.begin(); jter!=handlers_.end(); ++jter)
                                {
                                        if(*jter == iter->receiver_)
                                        {
                                                pipes.push_back(*jter);
                                                added = true;
                                                break;
                                        }
                                }
                                handlersMutex_.unlock();
                        }
                        if(!added)
                        {
                                // Add nulls
                                pipes.push_back(0);
                        }
                }
        }

        pipesMutex_.unlock();
        return pipes;
}

void UEventsManager::_createPipe(
                const UEventsSender * sender,
                const UEventsHandler * receiver,
                const std::string & eventName)
{
        pipesMutex_.lock();
        bool exist = false;
        for(std::list<Pipe>::iterator iter=pipes_.begin(); iter!= pipes_.end();++iter)
        {
                if(iter->sender_ == sender && iter->receiver_ == receiver && iter->eventName_.compare(eventName) == 0)
                {
                        exist = true;
                        break;
                }
        }

        if(!exist)
        {
                bool handlerFound = false;
                handlersMutex_.lock();
                for(std::list<UEventsHandler*>::iterator iter=handlers_.begin(); iter!=handlers_.end(); ++iter)
                {
                        if(*iter == receiver)
                        {
                                handlerFound = true;
                                break;
                        }
                }
                handlersMutex_.unlock();
                if(handlerFound)
                {
                        pipes_.push_back(Pipe(sender, receiver, eventName));
                }
                else
                {
                        UERROR("Cannot create the pipe because the receiver is not yet "
                                   "added to UEventsManager's handlers list.");
                }
        }
        else
        {
                UWARN("Pipe between sender %p and receiver %p with event %s was already created.",
                                sender, receiver, eventName.c_str());
        }
        pipesMutex_.unlock();
}

void UEventsManager::_removePipe(
                const UEventsSender * sender,
                const UEventsHandler * receiver,
                const std::string & eventName)
{
        pipesMutex_.lock();

        bool removed = false;
        for(std::list<Pipe>::iterator iter=pipes_.begin(); iter!= pipes_.end();)
        {
                if(iter->sender_ == sender && iter->receiver_ == receiver && iter->eventName_.compare(eventName) == 0)
                {
                        iter = pipes_.erase(iter);
                        removed = true;
                }
                else
                {
                        ++iter;
                }
        }

        if(!removed)
        {
                UWARN("Pipe between sender %p and receiver %p with event %s didn't exist.",
                                sender, receiver, eventName.c_str());
        }

        pipesMutex_.unlock();
}

void UEventsManager::_removeAllPipes(const UEventsSender * sender)
{
        pipesMutex_.lock();
        for(std::list<Pipe>::iterator iter=pipes_.begin(); iter!=pipes_.end();)
        {
                if(iter->sender_ == sender)
                {
                        iter = pipes_.erase(iter);
                }
                else
                {
                        ++iter;
                }
        }
        pipesMutex_.unlock();
}

void UEventsManager::_removeNullPipes(const UEventsSender * sender)
{
        pipesMutex_.lock();
        for(std::list<Pipe>::iterator iter=pipes_.begin(); iter!=pipes_.end();)
        {
                if(iter->receiver_ == 0)
                {
                        iter = pipes_.erase(iter);
                }
                else
                {
                        ++iter;
                }
        }
        pipesMutex_.unlock();
}