diff options
-rw-r--r-- | src/corelib/kernel/qeventdispatcher_symbian.cpp | 27 | ||||
-rw-r--r-- | src/corelib/kernel/qeventdispatcher_symbian_p.h | 3 |
2 files changed, 25 insertions, 5 deletions
diff --git a/src/corelib/kernel/qeventdispatcher_symbian.cpp b/src/corelib/kernel/qeventdispatcher_symbian.cpp index 47dd558..84825af 100644 --- a/src/corelib/kernel/qeventdispatcher_symbian.cpp +++ b/src/corelib/kernel/qeventdispatcher_symbian.cpp @@ -210,8 +210,10 @@ void QWakeUpActiveObject::RunL() QTimerActiveObject::QTimerActiveObject(QEventDispatcherSymbian *dispatcher, SymbianTimerInfo *timerInfo) : QActiveObject((timerInfo->interval) ? TIMER_PRIORITY : NULLTIMER_PRIORITY , dispatcher), - m_timerInfo(timerInfo) + m_timerInfo(timerInfo), m_expectedTimeSinceLastEvent(0) { + // start the timeout timer to ensure initialisation + m_timeoutTimer.start(); } QTimerActiveObject::~QTimerActiveObject() @@ -255,10 +257,23 @@ void QTimerActiveObject::StartTimer() m_rTimer.After(iStatus, MAX_SYMBIAN_TIMEOUT_MS * 1000); m_timerInfo->msLeft -= MAX_SYMBIAN_TIMEOUT_MS; } else { - //HighRes gives the 1ms accuracy expected by Qt, the +1 is to ensure that - //"Timers will never time out earlier than the specified timeout value" - //condition is always met. - m_rTimer.HighRes(iStatus, (m_timerInfo->msLeft + 1) * 1000); + // this algorithm implements drift correction for repeating timers + // calculate how late we are for this event + int timeSinceLastEvent = m_timeoutTimer.restart(); + int overshoot = timeSinceLastEvent - m_expectedTimeSinceLastEvent; + if (overshoot > m_timerInfo->msLeft) { + // we skipped a whole timeout, restart from here + overshoot = 0; + } + // calculate when the next event should happen + int waitTime = m_timerInfo->msLeft - overshoot; + m_expectedTimeSinceLastEvent = waitTime; + // limit the actual ms wait time to avoid wild corrections + // this will cause the real event time to slowly drift back to the expected event time + // measurements show that Symbian timers always fire 1 or 2 ms late + const int limit = 4; + waitTime = qMax(m_timerInfo->msLeft - limit, waitTime); + m_rTimer.HighRes(iStatus, waitTime * 1000); m_timerInfo->msLeft = 0; } SetActive(); @@ -305,6 +320,8 @@ void QTimerActiveObject::Start() if (!m_rTimer.Handle()) { qt_symbian_throwIfError(m_rTimer.CreateLocal()); } + m_timeoutTimer.start(); + m_expectedTimeSinceLastEvent = 0; StartTimer(); } else { iStatus = KRequestPending; diff --git a/src/corelib/kernel/qeventdispatcher_symbian_p.h b/src/corelib/kernel/qeventdispatcher_symbian_p.h index b785aea..a31a446 100644 --- a/src/corelib/kernel/qeventdispatcher_symbian_p.h +++ b/src/corelib/kernel/qeventdispatcher_symbian_p.h @@ -63,6 +63,7 @@ #include <qwaitcondition.h> #include <qsocketnotifier.h> #include <qdatetime.h> +#include <qelapsedtimer.h> #include <e32base.h> @@ -143,6 +144,8 @@ private: private: SymbianTimerInfo *m_timerInfo; + QElapsedTimer m_timeoutTimer; + int m_expectedTimeSinceLastEvent; RTimer m_rTimer; }; |