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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 16:49:04 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 16:49:04 +0000 |
commit | 16f504a9dca3fe3b70568f67b7d41241ae485288 (patch) | |
tree | c60f36ada0496ba928b7161059ba5ab1ab224f9d /src/libs/xpcom18a4/xpcom/threads/nsTimerImpl.cpp | |
parent | Initial commit. (diff) | |
download | virtualbox-upstream.tar.xz virtualbox-upstream.zip |
Adding upstream version 7.0.6-dfsg.upstream/7.0.6-dfsgupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/libs/xpcom18a4/xpcom/threads/nsTimerImpl.cpp')
-rw-r--r-- | src/libs/xpcom18a4/xpcom/threads/nsTimerImpl.cpp | 642 |
1 files changed, 642 insertions, 0 deletions
diff --git a/src/libs/xpcom18a4/xpcom/threads/nsTimerImpl.cpp b/src/libs/xpcom18a4/xpcom/threads/nsTimerImpl.cpp new file mode 100644 index 00000000..dc19452f --- /dev/null +++ b/src/libs/xpcom18a4/xpcom/threads/nsTimerImpl.cpp @@ -0,0 +1,642 @@ +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * Version: MPL 1.1/GPL 2.0/LGPL 2.1 + * + * ***** BEGIN LICENSE BLOCK ***** + * Version: MPL 1.1/GPL 2.0/LGPL 2.1 + * + * The contents of this file are subject to the Mozilla Public License Version + * 1.1 (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * http://www.mozilla.org/MPL/ + * + * Software distributed under the License is distributed on an "AS IS" basis, + * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License + * for the specific language governing rights and limitations under the + * License. + * + * The Original Code is mozilla.org code. + * + * The Initial Developer of the Original Code is + * Netscape Communications Corporation. + * Portions created by the Initial Developer are Copyright (C) 2001 + * the Initial Developer. All Rights Reserved. + * + * Contributor(s): + * Stuart Parmenter <pavlov@netscape.com> + * + * Alternatively, the contents of this file may be used under the terms of + * either of the GNU General Public License Version 2 or later (the "GPL"), + * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), + * in which case the provisions of the GPL or the LGPL are applicable instead + * of those above. If you wish to allow use of your version of this file only + * under the terms of either the GPL or the LGPL, and not to allow others to + * use your version of this file under the terms of the MPL, indicate your + * decision by deleting the provisions above and replace them with the notice + * and other provisions required by the GPL or the LGPL. If you do not delete + * the provisions above, a recipient may use your version of this file under + * the terms of any one of the MPL, the GPL or the LGPL. + * + * ***** END LICENSE BLOCK ***** */ + +#include "nsTimerImpl.h" +#include "TimerThread.h" +#include "nsAutoLock.h" + +#include "nsVoidArray.h" + +#include "nsIEventQueue.h" + +#include "prmem.h" + +static PRInt32 gGenerator = 0; +static TimerThread* gThread = nsnull; +static PRBool gFireOnIdle = PR_FALSE; +static nsTimerManager* gManager = nsnull; + +#ifdef DEBUG_TIMERS +#include <math.h> + +double nsTimerImpl::sDeltaSumSquared = 0; +double nsTimerImpl::sDeltaSum = 0; +double nsTimerImpl::sDeltaNum = 0; + +static void +myNS_MeanAndStdDev(double n, double sumOfValues, double sumOfSquaredValues, + double *meanResult, double *stdDevResult) +{ + double mean = 0.0, var = 0.0, stdDev = 0.0; + if (n > 0.0 && sumOfValues >= 0) { + mean = sumOfValues / n; + double temp = (n * sumOfSquaredValues) - (sumOfValues * sumOfValues); + if (temp < 0.0 || n <= 1) + var = 0.0; + else + var = temp / (n * (n - 1)); + // for some reason, Windows says sqrt(0.0) is "-1.#J" (?!) so do this: + stdDev = var != 0.0 ? sqrt(var) : 0.0; + } + *meanResult = mean; + *stdDevResult = stdDev; +} +#endif + +NS_IMPL_THREADSAFE_QUERY_INTERFACE2(nsTimerImpl, nsITimer, nsITimerInternal) +NS_IMPL_THREADSAFE_ADDREF(nsTimerImpl) + +NS_IMETHODIMP_(nsrefcnt) nsTimerImpl::Release(void) +{ + nsrefcnt count; + + NS_PRECONDITION(0 != mRefCnt, "dup release"); + count = PR_AtomicDecrement((PRInt32 *)&mRefCnt); + NS_LOG_RELEASE(this, count, "nsTimerImpl"); + if (count == 0) { + mRefCnt = 1; /* stabilize */ + + /* enable this to find non-threadsafe destructors: */ + /* NS_ASSERT_OWNINGTHREAD(nsTimerImpl); */ + NS_DELETEXPCOM(this); + return 0; + } + + // If only one reference remains, and mArmed is set, then the ref must be + // from the TimerThread::mTimers array, so we Cancel this timer to remove + // the mTimers element, and return 0 if Cancel in fact disarmed the timer. + // + // We use an inlined version of nsTimerImpl::Cancel here to check for the + // NS_ERROR_NOT_AVAILABLE code returned by gThread->RemoveTimer when this + // timer is not found in the mTimers array -- i.e., when the timer was not + // in fact armed once we acquired TimerThread::mLock, in spite of mArmed + // being true here. That can happen if the armed timer is being fired by + // TimerThread::Run as we race and test mArmed just before it is cleared by + // the timer thread. If the RemoveTimer call below doesn't find this timer + // in the mTimers array, then the last ref to this timer is held manually + // and temporarily by the TimerThread, so we should fall through to the + // final return and return 1, not 0. + // + // The original version of this thread-based timer code kept weak refs from + // TimerThread::mTimers, removing this timer's weak ref in the destructor, + // but that leads to double-destructions in the race described above, and + // adding mArmed doesn't help, because destructors can't be deferred, once + // begun. But by combining reference-counting and a specialized Release + // method with "is this timer still in the mTimers array once we acquire + // the TimerThread's lock" testing, we defer destruction until we're sure + // that only one thread has its hot little hands on this timer. + // + // Note that both approaches preclude a timer creator, and everyone else + // except the TimerThread who might have a strong ref, from dropping all + // their strong refs without implicitly canceling the timer. Timers need + // non-mTimers-element strong refs to stay alive. + + if (count == 1 && mArmed) { + mCanceled = PR_TRUE; + + if (NS_SUCCEEDED(gThread->RemoveTimer(this))) + return 0; + } + + return count; +} + +nsTimerImpl::nsTimerImpl() : + mClosure(nsnull), + mCallbackType(CALLBACK_TYPE_UNKNOWN), + mIdle(PR_TRUE), + mFiring(PR_FALSE), + mArmed(PR_FALSE), + mCanceled(PR_FALSE), + mGeneration(0), + mDelay(0), + mTimeout(0) +{ + // XXXbsmedberg: shouldn't this be in Init()? + nsIThread::GetCurrent(getter_AddRefs(mCallingThread)); + + mCallback.c = nsnull; + +#ifdef DEBUG_TIMERS + mStart = 0; + mStart2 = 0; +#endif +} + +nsTimerImpl::~nsTimerImpl() +{ + ReleaseCallback(); +} + +//static +nsresult +nsTimerImpl::Startup() +{ + nsresult rv; + + gThread = new TimerThread(); + if (!gThread) return NS_ERROR_OUT_OF_MEMORY; + + NS_ADDREF(gThread); + rv = gThread->InitLocks(); + + if (NS_FAILED(rv)) { + NS_RELEASE(gThread); + } + + return rv; +} + +void nsTimerImpl::Shutdown() +{ +#ifdef DEBUG_TIMERS + if (PR_LOG_TEST(gTimerLog, PR_LOG_DEBUG)) { + double mean = 0, stddev = 0; + myNS_MeanAndStdDev(sDeltaNum, sDeltaSum, sDeltaSumSquared, &mean, &stddev); + + PR_LOG(gTimerLog, PR_LOG_DEBUG, ("sDeltaNum = %f, sDeltaSum = %f, sDeltaSumSquared = %f\n", sDeltaNum, sDeltaSum, sDeltaSumSquared)); + PR_LOG(gTimerLog, PR_LOG_DEBUG, ("mean: %fms, stddev: %fms\n", mean, stddev)); + } +#endif + + if (!gThread) + return; + + gThread->Shutdown(); + NS_RELEASE(gThread); + + gFireOnIdle = PR_FALSE; +} + + +nsresult nsTimerImpl::InitCommon(PRUint32 aType, PRUint32 aDelay) +{ + nsresult rv; + + NS_ENSURE_TRUE(gThread, NS_ERROR_NOT_INITIALIZED); + + rv = gThread->Init(); + NS_ENSURE_SUCCESS(rv, rv); + + /** + * In case of re-Init, both with and without a preceding Cancel, clear the + * mCanceled flag and assign a new mGeneration. But first, remove any armed + * timer from the timer thread's list. + * + * If we are racing with the timer thread to remove this timer and we lose, + * the RemoveTimer call made here will fail to find this timer in the timer + * thread's list, and will return false harmlessly. We test mArmed here to + * avoid the small overhead in RemoveTimer of locking the timer thread and + * checking its list for this timer. It's safe to test mArmed even though + * it might be cleared on another thread in the next cycle (or even already + * be cleared by another CPU whose store hasn't reached our CPU's cache), + * because RemoveTimer is idempotent. + */ + if (mArmed) + gThread->RemoveTimer(this); + mCanceled = PR_FALSE; + mGeneration = PR_AtomicIncrement(&gGenerator); + + mType = (PRUint8)aType; + SetDelayInternal(aDelay); + + return gThread->AddTimer(this); +} + +NS_IMETHODIMP nsTimerImpl::InitWithFuncCallback(nsTimerCallbackFunc aFunc, + void *aClosure, + PRUint32 aDelay, + PRUint32 aType) +{ + ReleaseCallback(); + mCallbackType = CALLBACK_TYPE_FUNC; + mCallback.c = aFunc; + mClosure = aClosure; + + return InitCommon(aType, aDelay); +} + +NS_IMETHODIMP nsTimerImpl::InitWithCallback(nsITimerCallback *aCallback, + PRUint32 aDelay, + PRUint32 aType) +{ + ReleaseCallback(); + mCallbackType = CALLBACK_TYPE_INTERFACE; + mCallback.i = aCallback; + NS_ADDREF(mCallback.i); + + return InitCommon(aType, aDelay); +} + +NS_IMETHODIMP nsTimerImpl::Init(nsIObserver *aObserver, + PRUint32 aDelay, + PRUint32 aType) +{ + ReleaseCallback(); + mCallbackType = CALLBACK_TYPE_OBSERVER; + mCallback.o = aObserver; + NS_ADDREF(mCallback.o); + + return InitCommon(aType, aDelay); +} + +NS_IMETHODIMP nsTimerImpl::Cancel() +{ + mCanceled = PR_TRUE; + + if (gThread) + gThread->RemoveTimer(this); + + return NS_OK; +} + +NS_IMETHODIMP nsTimerImpl::SetDelay(PRUint32 aDelay) +{ + // If we're already repeating precisely, update mTimeout now so that the + // new delay takes effect in the future. + if (mTimeout != 0 && mType == TYPE_REPEATING_PRECISE) + mTimeout = PR_IntervalNow(); + + SetDelayInternal(aDelay); + + if (!mFiring && gThread) + gThread->TimerDelayChanged(this); + + return NS_OK; +} + +NS_IMETHODIMP nsTimerImpl::GetDelay(PRUint32* aDelay) +{ + *aDelay = mDelay; + return NS_OK; +} + +NS_IMETHODIMP nsTimerImpl::SetType(PRUint32 aType) +{ + mType = (PRUint8)aType; + // XXX if this is called, we should change the actual type.. this could effect + // repeating timers. we need to ensure in Fire() that if mType has changed + // during the callback that we don't end up with the timer in the queue twice. + return NS_OK; +} + +NS_IMETHODIMP nsTimerImpl::GetType(PRUint32* aType) +{ + *aType = mType; + return NS_OK; +} + + +NS_IMETHODIMP nsTimerImpl::GetClosure(void** aClosure) +{ + *aClosure = mClosure; + return NS_OK; +} + + +NS_IMETHODIMP nsTimerImpl::GetIdle(PRBool *aIdle) +{ + *aIdle = mIdle; + return NS_OK; +} + +NS_IMETHODIMP nsTimerImpl::SetIdle(PRBool aIdle) +{ + mIdle = aIdle; + return NS_OK; +} + +void nsTimerImpl::Fire() +{ + if (mCanceled) + return; + + PRIntervalTime now = PR_IntervalNow(); +#ifdef DEBUG_TIMERS + if (PR_LOG_TEST(gTimerLog, PR_LOG_DEBUG)) { + PRIntervalTime a = now - mStart; // actual delay in intervals + PRUint32 b = PR_MillisecondsToInterval(mDelay); // expected delay in intervals + PRUint32 d = PR_IntervalToMilliseconds((a > b) ? a - b : b - a); // delta in ms + sDeltaSum += d; + sDeltaSumSquared += double(d) * double(d); + sDeltaNum++; + + PR_LOG(gTimerLog, PR_LOG_DEBUG, ("[this=%p] expected delay time %4dms\n", this, mDelay)); + PR_LOG(gTimerLog, PR_LOG_DEBUG, ("[this=%p] actual delay time %4dms\n", this, PR_IntervalToMilliseconds(a))); + PR_LOG(gTimerLog, PR_LOG_DEBUG, ("[this=%p] (mType is %d) -------\n", this, mType)); + PR_LOG(gTimerLog, PR_LOG_DEBUG, ("[this=%p] delta %4dms\n", this, (a > b) ? (PRInt32)d : -(PRInt32)d)); + + mStart = mStart2; + mStart2 = 0; + } +#endif + + PRIntervalTime timeout = mTimeout; + if (mType == TYPE_REPEATING_PRECISE) { + // Precise repeating timers advance mTimeout by mDelay without fail before + // calling Fire(). + timeout -= PR_MillisecondsToInterval(mDelay); + } + gThread->UpdateFilter(mDelay, timeout, now); + + mFiring = PR_TRUE; + + switch (mCallbackType) { + case CALLBACK_TYPE_FUNC: + mCallback.c(this, mClosure); + break; + case CALLBACK_TYPE_INTERFACE: + mCallback.i->Notify(this); + break; + case CALLBACK_TYPE_OBSERVER: + mCallback.o->Observe(NS_STATIC_CAST(nsITimer*,this), + NS_TIMER_CALLBACK_TOPIC, + nsnull); + break; + default:; + } + + mFiring = PR_FALSE; + +#ifdef DEBUG_TIMERS + if (PR_LOG_TEST(gTimerLog, PR_LOG_DEBUG)) { + PR_LOG(gTimerLog, PR_LOG_DEBUG, + ("[this=%p] Took %dms to fire timer callback\n", + this, PR_IntervalToMilliseconds(PR_IntervalNow() - now))); + } +#endif + + if (mType == TYPE_REPEATING_SLACK) { + SetDelayInternal(mDelay); // force mTimeout to be recomputed. + if (gThread) + gThread->AddTimer(this); + } +} + + +struct TimerEventType : public PLEvent { + PRInt32 mGeneration; +#ifdef DEBUG_TIMERS + PRIntervalTime mInitTime; +#endif +}; + + +void* handleTimerEvent(TimerEventType* event) +{ + nsTimerImpl* timer = NS_STATIC_CAST(nsTimerImpl*, event->owner); + if (event->mGeneration != timer->GetGeneration()) + return nsnull; + +#ifdef DEBUG_TIMERS + if (PR_LOG_TEST(gTimerLog, PR_LOG_DEBUG)) { + PRIntervalTime now = PR_IntervalNow(); + PR_LOG(gTimerLog, PR_LOG_DEBUG, + ("[this=%p] time between PostTimerEvent() and Fire(): %dms\n", + event->owner, PR_IntervalToMilliseconds(now - event->mInitTime))); + } +#endif + + if (gFireOnIdle) { + PRBool idle = PR_FALSE; + timer->GetIdle(&idle); + if (idle) { + NS_ASSERTION(gManager, "Global Thread Manager is null!"); + if (gManager) + gManager->AddIdleTimer(timer); + return nsnull; + } + } + + timer->Fire(); + + return nsnull; +} + +void destroyTimerEvent(TimerEventType* event) +{ + nsTimerImpl *timer = NS_STATIC_CAST(nsTimerImpl*, event->owner); + NS_RELEASE(timer); + PR_DELETE(event); +} + + +void nsTimerImpl::PostTimerEvent() +{ + // XXX we may want to reuse the PLEvent in the case of repeating timers. + TimerEventType* event; + + // construct + event = PR_NEW(TimerEventType); + if (!event) + return; + + // initialize + PL_InitEvent((PLEvent*)event, this, + (PLHandleEventProc)handleTimerEvent, + (PLDestroyEventProc)destroyTimerEvent); + + // Since TimerThread addref'd 'this' for us, we don't need to addref here. + // We will release in destroyMyEvent. We do need to copy the generation + // number from this timer into the event, so we can avoid firing a timer + // that was re-initialized after being canceled. + event->mGeneration = mGeneration; + +#ifdef DEBUG_TIMERS + if (PR_LOG_TEST(gTimerLog, PR_LOG_DEBUG)) { + event->mInitTime = PR_IntervalNow(); + } +#endif + + // If this is a repeating precise timer, we need to calculate the time for + // the next timer to fire before we make the callback. + if (mType == TYPE_REPEATING_PRECISE) { + SetDelayInternal(mDelay); + if (gThread) + gThread->AddTimer(this); + } + + PRThread *thread; + nsresult rv = mCallingThread->GetPRThread(&thread); + if (NS_FAILED(rv)) { + NS_WARNING("Dropping timer event because thread is dead"); + return; + } + + nsCOMPtr<nsIEventQueue> queue; + if (gThread) + gThread->mEventQueueService->GetThreadEventQueue(thread, getter_AddRefs(queue)); + if (queue) + queue->PostEvent(event); +} + +void nsTimerImpl::SetDelayInternal(PRUint32 aDelay) +{ + PRIntervalTime delayInterval = PR_MillisecondsToInterval(aDelay); + if (delayInterval > DELAY_INTERVAL_MAX) { + delayInterval = DELAY_INTERVAL_MAX; + aDelay = PR_IntervalToMilliseconds(delayInterval); + } + + mDelay = aDelay; + + PRIntervalTime now = PR_IntervalNow(); + if (mTimeout == 0 || mType != TYPE_REPEATING_PRECISE) + mTimeout = now; + + mTimeout += delayInterval; + +#ifdef DEBUG_TIMERS + if (PR_LOG_TEST(gTimerLog, PR_LOG_DEBUG)) { + if (mStart == 0) + mStart = now; + else + mStart2 = now; + } +#endif +} + +/** + * Timer Manager code + */ + +NS_IMPL_THREADSAFE_ISUPPORTS1(nsTimerManager, nsITimerManager) + +nsTimerManager::nsTimerManager() +{ + mLock = PR_NewLock(); + gManager = this; +} + +nsTimerManager::~nsTimerManager() +{ + gManager = nsnull; + PR_DestroyLock(mLock); + + nsTimerImpl *theTimer; + PRInt32 count = mIdleTimers.Count(); + + for (PRInt32 i = 0; i < count; i++) { + theTimer = NS_STATIC_CAST(nsTimerImpl*, mIdleTimers[i]); + NS_IF_RELEASE(theTimer); + } +} + +NS_IMETHODIMP nsTimerManager::SetUseIdleTimers(PRBool aUseIdleTimers) +{ + if (aUseIdleTimers == PR_FALSE && gFireOnIdle == PR_TRUE) + return NS_ERROR_FAILURE; + + gFireOnIdle = aUseIdleTimers; + + return NS_OK; +} + +NS_IMETHODIMP nsTimerManager::GetUseIdleTimers(PRBool *aUseIdleTimers) +{ + *aUseIdleTimers = gFireOnIdle; + return NS_OK; +} + +NS_IMETHODIMP nsTimerManager::HasIdleTimers(PRBool *aHasTimers) +{ + nsAutoLock lock (mLock); + PRUint32 count = mIdleTimers.Count(); + *aHasTimers = (count != 0); + return NS_OK; +} + +nsresult nsTimerManager::AddIdleTimer(nsITimer* timer) +{ + if (!timer) + return NS_ERROR_FAILURE; + nsAutoLock lock(mLock); + mIdleTimers.AppendElement(timer); + NS_ADDREF(timer); + return NS_OK; +} + +NS_IMETHODIMP nsTimerManager::FireNextIdleTimer() +{ + if (!gFireOnIdle || !nsIThread::IsMainThread()) { + return NS_OK; + } + + nsTimerImpl *theTimer = nsnull; + + { + nsAutoLock lock (mLock); + PRUint32 count = mIdleTimers.Count(); + + if (count == 0) + return NS_OK; + + theTimer = NS_STATIC_CAST(nsTimerImpl*, mIdleTimers[0]); + mIdleTimers.RemoveElement(theTimer); + } + + theTimer->Fire(); + + NS_RELEASE(theTimer); + + return NS_OK; +} + + +// NOT FOR PUBLIC CONSUMPTION! +nsresult +NS_NewTimer(nsITimer* *aResult, nsTimerCallbackFunc aCallback, void *aClosure, + PRUint32 aDelay, PRUint32 aType) +{ + nsTimerImpl* timer = new nsTimerImpl(); + if (timer == nsnull) + return NS_ERROR_OUT_OF_MEMORY; + NS_ADDREF(timer); + + nsresult rv = timer->InitWithFuncCallback(aCallback, aClosure, + aDelay, aType); + if (NS_FAILED(rv)) { + NS_RELEASE(timer); + return rv; + } + + *aResult = timer; + return NS_OK; +} |