source: vendor/synergy/current/lib/base/CEventQueue.cpp

;/*
 * synergy -- mouse and keyboard sharing utility
 * Copyright (C) 2004 Chris Schoeneman
 * 
 * This package is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * found in the file COPYING that should have accompanied this file.
 * 
 * This package 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.
 */

#include "CEventQueue.h"
#include "CLog.h"
#include "CSimpleEventQueueBuffer.h"
#include "CStopwatch.h"
#include "IEventJob.h"
#include "CArch.h"

// interrupt handler.  this just adds a quit event to the queue.
static
void
interrupt(CArch::ESignal, void*)
{
        EVENTQUEUE->addEvent(CEvent(CEvent::kQuit));
}


//
// CEventQueue
//

CEventQueue::CEventQueue() :
        m_nextType(CEvent::kLast)
{
        setInstance(this);
        m_mutex = ARCH->newMutex();
        ARCH->setSignalHandler(CArch::kINTERRUPT, &interrupt, NULL);
        ARCH->setSignalHandler(CArch::kTERMINATE, &interrupt, NULL);
        m_buffer = new CSimpleEventQueueBuffer;
}

CEventQueue::~CEventQueue()
{
        delete m_buffer;
        ARCH->setSignalHandler(CArch::kINTERRUPT, NULL, NULL);
        ARCH->setSignalHandler(CArch::kTERMINATE, NULL, NULL);
        ARCH->closeMutex(m_mutex);
        setInstance(NULL);
}

CEvent::Type
CEventQueue::registerType(const char* name)
{
        CArchMutexLock lock(m_mutex);
        m_typeMap.insert(std::make_pair(m_nextType, name));
        LOG((CLOG_DEBUG1 "registered event type %s as %d", name, m_nextType));
        return m_nextType++;
}

CEvent::Type
CEventQueue::registerTypeOnce(CEvent::Type& type, const char* name)
{
        CArchMutexLock lock(m_mutex);
        if (type == CEvent::kUnknown) {
                m_typeMap.insert(std::make_pair(m_nextType, name));
                LOG((CLOG_DEBUG1 "registered event type %s as %d", name, m_nextType));
                type = m_nextType++;
        }
        return type;
}

const char*
CEventQueue::getTypeName(CEvent::Type type)
{
        switch (type) {
        case CEvent::kUnknown:
                return "nil";

        case CEvent::kQuit:
                return "quit";

        case CEvent::kSystem:
                return "system";

        case CEvent::kTimer:
                return "timer";

        default:
                CTypeMap::const_iterator i = m_typeMap.find(type);
                if (i == m_typeMap.end()) {
                        return "<unknown>";
                }
                else {
                        return i->second;
                }
        }
}

void
CEventQueue::adoptBuffer(IEventQueueBuffer* buffer)
{
        CArchMutexLock lock(m_mutex);

        // discard old buffer and old events
        delete m_buffer;
        for (CEventTable::iterator i = m_events.begin(); i != m_events.end(); ++i) {
                CEvent::deleteData(i->second);
        }
        m_events.clear();
        m_oldEventIDs.clear();

        // use new buffer
        m_buffer = buffer;
        if (m_buffer == NULL) {
                m_buffer = new CSimpleEventQueueBuffer;
        }
}

bool
CEventQueue::getEvent(CEvent& event, double timeout)
{
        CStopwatch timer(true);
retry:
        // if no events are waiting then handle timers and then wait
        while (m_buffer->isEmpty()) {
                // handle timers first
                if (hasTimerExpired(event)) {
                        return true;
                }

                // get time remaining in timeout
                double timeLeft = timeout - timer.getTime();
                if (timeout >= 0.0 && timeLeft <= 0.0) {
                        return false;
                }

                // get time until next timer expires.  if there is a timer
                // and it'll expire before the client's timeout then use
                // that duration for our timeout instead.
                double timerTimeout = getNextTimerTimeout();
                if (timeout < 0.0 || (timerTimeout >= 0.0 && timerTimeout < timeLeft)) {
                        timeLeft = timerTimeout;
                }

                // wait for an event
                m_buffer->waitForEvent(timeLeft);
        }

        // get the event
        UInt32 dataID;
        IEventQueueBuffer::Type type = m_buffer->getEvent(event, dataID);
        switch (type) {
        case IEventQueueBuffer::kNone:
                if (timeout < 0.0 || timeout <= timer.getTime()) {
                        // don't want to fail if client isn't expecting that
                        // so if getEvent() fails with an infinite timeout
                        // then just try getting another event.
                        goto retry;
                }
                return false;

        case IEventQueueBuffer::kSystem:
                return true;

        case IEventQueueBuffer::kUser:
                {
                        CArchMutexLock lock(m_mutex);
                        event = removeEvent(dataID);
                        return true;
                }

        default:
                assert(0 && "invalid event type");
                return false;
        }
}

bool
CEventQueue::dispatchEvent(const CEvent& event)
{
        void* target   = event.getTarget();
        IEventJob* job = getHandler(event.getType(), target);
        if (job == NULL) {
                job = getHandler(CEvent::kUnknown, target);
        }
        if (job != NULL) {
                job->run(event);
                return true;
        }
        return false;
}

void
CEventQueue::addEvent(const CEvent& event)
{
        // discard bogus event types
        switch (event.getType()) {
        case CEvent::kUnknown:
        case CEvent::kSystem:
        case CEvent::kTimer:
                return;

        default:
                break;
        }
        
        if ((event.getFlags() & CEvent::kDeliverImmediately) != 0) {
                dispatchEvent(event);
                CEvent::deleteData(event);
        }
        else {
                CArchMutexLock lock(m_mutex);
                
                // store the event's data locally
                UInt32 eventID = saveEvent(event);
                
                // add it
                if (!m_buffer->addEvent(eventID)) {
                        // failed to send event
                        removeEvent(eventID);
                        CEvent::deleteData(event);
                }
        }
}

CEventQueueTimer*
CEventQueue::newTimer(double duration, void* target)
{
        assert(duration > 0.0);

        CEventQueueTimer* timer = m_buffer->newTimer(duration, false);
        if (target == NULL) {
                target = timer;
        }
        CArchMutexLock lock(m_mutex);
        m_timers.insert(timer);
        // initial duration is requested duration plus whatever's on
        // the clock currently because the latter will be subtracted
        // the next time we check for timers.
        m_timerQueue.push(CTimer(timer, duration,
                                                        duration + m_time.getTime(), target, false));
        return timer;
}

CEventQueueTimer*
CEventQueue::newOneShotTimer(double duration, void* target)
{
        assert(duration > 0.0);

        CEventQueueTimer* timer = m_buffer->newTimer(duration, true);
        if (target == NULL) {
                target = timer;
        }
        CArchMutexLock lock(m_mutex);
        m_timers.insert(timer);
        // initial duration is requested duration plus whatever's on
        // the clock currently because the latter will be subtracted
        // the next time we check for timers.
        m_timerQueue.push(CTimer(timer, duration,
                                                        duration + m_time.getTime(), target, true));
        return timer;
}

void
CEventQueue::deleteTimer(CEventQueueTimer* timer)
{
        CArchMutexLock lock(m_mutex);
        for (CTimerQueue::iterator index = m_timerQueue.begin();
                                                        index != m_timerQueue.end(); ++index) {
                if (index->getTimer() == timer) {
                        m_timerQueue.erase(index);
                        break;
                }
        }
        CTimers::iterator index = m_timers.find(timer);
        if (index != m_timers.end()) {
                m_timers.erase(index);
        }
        m_buffer->deleteTimer(timer);
}

void
CEventQueue::adoptHandler(CEvent::Type type, void* target, IEventJob* handler)
{
        CArchMutexLock lock(m_mutex);
        IEventJob*& job = m_handlers[target][type];
        delete job;
        job = handler;
}

void
CEventQueue::removeHandler(CEvent::Type type, void* target)
{
        IEventJob* handler = NULL;
        {
                CArchMutexLock lock(m_mutex);
                CHandlerTable::iterator index = m_handlers.find(target);
                if (index != m_handlers.end()) {
                        CTypeHandlerTable& typeHandlers = index->second;
                        CTypeHandlerTable::iterator index2 = typeHandlers.find(type);
                        if (index2 != typeHandlers.end()) {
                                handler = index2->second;
                                typeHandlers.erase(index2);
                        }
                }
        }
        delete handler;
}

void
CEventQueue::removeHandlers(void* target)
{
        std::vector<IEventJob*> handlers;
        {
                CArchMutexLock lock(m_mutex);
                CHandlerTable::iterator index = m_handlers.find(target);
                if (index != m_handlers.end()) {
                        // copy to handlers array and clear table for target
                        CTypeHandlerTable& typeHandlers = index->second;
                        for (CTypeHandlerTable::iterator index2 = typeHandlers.begin();
                                                        index2 != typeHandlers.end(); ++index2) {
                                handlers.push_back(index2->second);
                        }
                        typeHandlers.clear();
                }
        }

        // delete handlers
        for (std::vector<IEventJob*>::iterator index = handlers.begin();
                                                        index != handlers.end(); ++index) {
                delete *index;
        }
}

bool
CEventQueue::isEmpty() const
{
        return (m_buffer->isEmpty() && getNextTimerTimeout() != 0.0);
}

IEventJob*
CEventQueue::getHandler(CEvent::Type type, void* target) const
{
        CArchMutexLock lock(m_mutex);
        CHandlerTable::const_iterator index = m_handlers.find(target);
        if (index != m_handlers.end()) {
                const CTypeHandlerTable& typeHandlers = index->second;
                CTypeHandlerTable::const_iterator index2 = typeHandlers.find(type);
                if (index2 != typeHandlers.end()) {
                        return index2->second;
                }
        }
        return NULL;
}

UInt32
CEventQueue::saveEvent(const CEvent& event)
{
        // choose id
        UInt32 id;
        if (!m_oldEventIDs.empty()) {
                // reuse an id
                id = m_oldEventIDs.back();
                m_oldEventIDs.pop_back();
        }
        else {
                // make a new id
                id = static_cast<UInt32>(m_events.size());
        }

        // save data
        m_events[id] = event;
        return id;
}

CEvent
CEventQueue::removeEvent(UInt32 eventID)
{
        // look up id
        CEventTable::iterator index = m_events.find(eventID);
        if (index == m_events.end()) {
                return CEvent();
        }

        // get data
        CEvent event = index->second;
        m_events.erase(index);

        // save old id for reuse
        m_oldEventIDs.push_back(eventID);

        return event;
}

bool
CEventQueue::hasTimerExpired(CEvent& event)
{
        // return true if there's a timer in the timer priority queue that
        // has expired.  if returning true then fill in event appropriately
        // and reset and reinsert the timer.
        if (m_timerQueue.empty()) {
                return false;
        }

        // get time elapsed since last check
        const double time = m_time.getTime();
        m_time.reset();

        // countdown elapsed time
        for (CTimerQueue::iterator index = m_timerQueue.begin();
                                                        index != m_timerQueue.end(); ++index) {
                (*index) -= time;
        }

        // done if no timers are expired
        if (m_timerQueue.top() > 0.0) {
                return false;
        }

        // remove timer from queue
        CTimer timer = m_timerQueue.top();
        m_timerQueue.pop();

        // prepare event and reset the timer's clock
        timer.fillEvent(m_timerEvent);
        event = CEvent(CEvent::kTimer, timer.getTarget(), &m_timerEvent);
        timer.reset();

        // reinsert timer into queue if it's not a one-shot
        if (!timer.isOneShot()) {
                m_timerQueue.push(timer);
        }

        return true;
}

double
CEventQueue::getNextTimerTimeout() const
{
        // return -1 if no timers, 0 if the top timer has expired, otherwise
        // the time until the top timer in the timer priority queue will
        // expire.
        if (m_timerQueue.empty()) {
                return -1.0;
        }
        if (m_timerQueue.top() <= 0.0) {
                return 0.0;
        }
        return m_timerQueue.top();
}


//
// CEventQueue::CTimer
//

CEventQueue::CTimer::CTimer(CEventQueueTimer* timer, double timeout,
                                double initialTime, void* target, bool oneShot) :
        m_timer(timer),
        m_timeout(timeout),
        m_target(target),
        m_oneShot(oneShot),
        m_time(initialTime)
{
        assert(m_timeout > 0.0);
}

CEventQueue::CTimer::~CTimer()
{
        // do nothing
}

void
CEventQueue::CTimer::reset()
{
        m_time = m_timeout;
}

CEventQueue::CTimer&
CEventQueue::CTimer::operator-=(double dt)
{
        m_time -= dt;
        return *this;
}

CEventQueue::CTimer::operator double() const
{
        return m_time;
}

bool
CEventQueue::CTimer::isOneShot() const
{
        return m_oneShot;
}

CEventQueueTimer*
CEventQueue::CTimer::getTimer() const
{
        return m_timer;
}

void*
CEventQueue::CTimer::getTarget() const
{
        return m_target;
}

void
CEventQueue::CTimer::fillEvent(CTimerEvent& event) const
{
        event.m_timer = m_timer;
        event.m_count = 0;
        if (m_time <= 0.0) {
                event.m_count = static_cast<UInt32>((m_timeout - m_time) / m_timeout);
        }
}

bool
CEventQueue::CTimer::operator<(const CTimer& t) const
{
        return m_time < t.m_time;
}