1 files changed, 462 insertions, 0 deletions
diff --git a/src/libs/xpcom18a4/xpcom/threads/TimerThread.cpp b/src/libs/xpcom18a4/xpcom/threads/TimerThread.cpp
new file mode 100644
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--- /dev/null
+++ b/src/libs/xpcom18a4/xpcom/threads/TimerThread.cpp
@@ -0,0 +1,462 @@
+/* -*- 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 "pratom.h"
+
+#include "nsIObserverService.h"
+#include "nsIServiceManager.h"
+
+NS_IMPL_THREADSAFE_ISUPPORTS3(TimerThread, nsIRunnable, nsISupportsWeakReference, nsIObserver)
+
+TimerThread::TimerThread() :
+  mInitInProgress(0),
+  mInitialized(PR_FALSE),
+  mLock(nsnull),
+  mCondVar(nsnull),
+  mShutdown(PR_FALSE),
+  mWaiting(PR_FALSE),
+  mSleeping(PR_FALSE),
+  mDelayLineCounter(0),
+  mMinTimerPeriod(0),
+  mTimeoutAdjustment(0)
+{
+}
+
+TimerThread::~TimerThread()
+{
+  if (mCondVar)
+    PR_DestroyCondVar(mCondVar);
+  if (mLock)
+    PR_DestroyLock(mLock);
+
+  mThread = nsnull;
+
+  PRInt32 n = mTimers.Count();
+  while (--n >= 0) {
+    nsTimerImpl *timer = NS_STATIC_CAST(nsTimerImpl *, mTimers[n]);
+    NS_RELEASE(timer);
+  }
+
+  nsCOMPtr<nsIObserverService> observerService = do_GetService("@mozilla.org/observer-service;1");
+  if (observerService) {
+    observerService->RemoveObserver(this, "sleep_notification");
+    observerService->RemoveObserver(this, "wake_notification");
+  }
+
+}
+
+nsresult
+TimerThread::InitLocks()
+{
+  NS_ASSERTION(!mLock, "InitLocks called twice?");
+  mLock = PR_NewLock();
+  if (!mLock)
+    return NS_ERROR_OUT_OF_MEMORY;
+
+  mCondVar = PR_NewCondVar(mLock);
+  if (!mCondVar)
+    return NS_ERROR_OUT_OF_MEMORY;
+
+  return NS_OK;
+}
+
+nsresult TimerThread::Init()
+{
+  if (mInitialized) {
+    if (!mThread)
+      return NS_ERROR_FAILURE;
+
+    return NS_OK;
+  }
+
+  if (PR_AtomicSet(&mInitInProgress, 1) == 0) {
+    nsresult rv;
+
+    mEventQueueService = do_GetService("@mozilla.org/event-queue-service;1", &rv);
+    if (NS_SUCCEEDED(rv)) {
+      nsCOMPtr<nsIObserverService> observerService
+        (do_GetService("@mozilla.org/observer-service;1", &rv));
+
+      if (NS_SUCCEEDED(rv)) {
+        // We hold on to mThread to keep the thread alive.
+        rv = NS_NewThread(getter_AddRefs(mThread),
+                          NS_STATIC_CAST(nsIRunnable*, this),
+                          0,
+                          PR_JOINABLE_THREAD,
+                          PR_PRIORITY_NORMAL,
+                          PR_GLOBAL_THREAD);
+
+        if (NS_FAILED(rv)) {
+          mThread = nsnull;
+        }
+        else {
+          observerService->AddObserver(this, "sleep_notification", PR_TRUE);
+          observerService->AddObserver(this, "wake_notification", PR_TRUE);
+        }
+      }
+    }
+
+    PR_Lock(mLock);
+    mInitialized = PR_TRUE;
+    PR_NotifyAllCondVar(mCondVar);
+    PR_Unlock(mLock);
+  }
+  else {
+    PR_Lock(mLock);
+    while (!mInitialized) {
+      PR_WaitCondVar(mCondVar, PR_INTERVAL_NO_TIMEOUT);
+    }
+    PR_Unlock(mLock);
+  }
+
+  if (!mThread)
+    return NS_ERROR_FAILURE;
+
+  return NS_OK;
+}
+
+nsresult TimerThread::Shutdown()
+{
+  if (!mThread)
+    return NS_ERROR_NOT_INITIALIZED;
+
+  {   // lock scope
+    nsAutoLock lock(mLock);
+
+    mShutdown = PR_TRUE;
+
+    // notify the cond var so that Run() can return
+    if (mCondVar && mWaiting)
+      PR_NotifyCondVar(mCondVar);
+
+    nsTimerImpl *timer;
+    for (PRInt32 i = mTimers.Count() - 1; i >= 0; i--) {
+      timer = NS_STATIC_CAST(nsTimerImpl*, mTimers[i]);
+      RemoveTimerInternal(timer);
+    }
+  }
+
+  mThread->Join();    // wait for the thread to die
+  return NS_OK;
+}
+
+// Keep track of how early (positive slack) or late (negative slack) timers
+// are running, and use the filtered slack number to adaptively estimate how
+// early timers should fire to be "on time".
+void TimerThread::UpdateFilter(PRUint32 aDelay, PRIntervalTime aTimeout,
+                               PRIntervalTime aNow)
+{
+  PRInt32 slack = (PRInt32) (aTimeout - aNow);
+  double smoothSlack = 0;
+  PRUint32 i, filterLength;
+  static PRIntervalTime kFilterFeedbackMaxTicks =
+    PR_MillisecondsToInterval(FILTER_FEEDBACK_MAX);
+
+  if (slack > 0) {
+    if (slack > (PRInt32)kFilterFeedbackMaxTicks)
+      slack = kFilterFeedbackMaxTicks;
+  } else {
+    if (slack < -(PRInt32)kFilterFeedbackMaxTicks)
+      slack = -(PRInt32)kFilterFeedbackMaxTicks;
+  }
+  mDelayLine[mDelayLineCounter & DELAY_LINE_LENGTH_MASK] = slack;
+  if (++mDelayLineCounter < DELAY_LINE_LENGTH) {
+    // Startup mode: accumulate a full delay line before filtering.
+    PR_ASSERT(mTimeoutAdjustment == 0);
+    filterLength = 0;
+  } else {
+    // Past startup: compute number of filter taps based on mMinTimerPeriod.
+    if (mMinTimerPeriod == 0) {
+      mMinTimerPeriod = (aDelay != 0) ? aDelay : 1;
+    } else if (aDelay != 0 && aDelay < mMinTimerPeriod) {
+      mMinTimerPeriod = aDelay;
+    }
+
+    filterLength = (PRUint32) (FILTER_DURATION / mMinTimerPeriod);
+    if (filterLength > DELAY_LINE_LENGTH)
+      filterLength = DELAY_LINE_LENGTH;
+    else if (filterLength < 4)
+      filterLength = 4;
+
+    for (i = 1; i <= filterLength; i++)
+      smoothSlack += mDelayLine[(mDelayLineCounter-i) & DELAY_LINE_LENGTH_MASK];
+    smoothSlack /= filterLength;
+
+    // XXXbe do we need amplification?  hacking a fudge factor, need testing...
+    mTimeoutAdjustment = (PRInt32) (smoothSlack * 1.5);
+  }
+
+#ifdef DEBUG_TIMERS
+  if (PR_LOG_TEST(gTimerLog, PR_LOG_DEBUG)) {
+    PR_LOG(gTimerLog, PR_LOG_DEBUG,
+           ("UpdateFilter: smoothSlack = %g, filterLength = %u\n",
+            smoothSlack, filterLength));
+  }
+#endif
+}
+
+/* void Run(); */
+NS_IMETHODIMP TimerThread::Run()
+{
+  nsAutoLock lock(mLock);
+
+  while (!mShutdown) {
+    PRIntervalTime waitFor;
+
+    if (mSleeping) {
+      // Sleep for 0.1 seconds while not firing timers.
+      waitFor = PR_MillisecondsToInterval(100);
+    } else {
+      waitFor = PR_INTERVAL_NO_TIMEOUT;
+      PRIntervalTime now = PR_IntervalNow();
+      nsTimerImpl *timer = nsnull;
+
+      if (mTimers.Count() > 0) {
+        timer = NS_STATIC_CAST(nsTimerImpl*, mTimers[0]);
+
+        if (!TIMER_LESS_THAN(now, timer->mTimeout + mTimeoutAdjustment)) {
+    next:
+          // NB: AddRef before the Release under RemoveTimerInternal to avoid
+          // mRefCnt passing through zero, in case all other refs than the one
+          // from mTimers have gone away (the last non-mTimers[i]-ref's Release
+          // must be racing with us, blocked in gThread->RemoveTimer waiting
+          // for TimerThread::mLock, under nsTimerImpl::Release.
+
+          NS_ADDREF(timer);
+          RemoveTimerInternal(timer);
+
+          // We release mLock around the Fire call to avoid deadlock.
+          lock.unlock();
+
+#ifdef DEBUG_TIMERS
+          if (PR_LOG_TEST(gTimerLog, PR_LOG_DEBUG)) {
+            PR_LOG(gTimerLog, PR_LOG_DEBUG,
+                   ("Timer thread woke up %dms from when it was supposed to\n",
+                    (now >= timer->mTimeout)
+                    ? PR_IntervalToMilliseconds(now - timer->mTimeout)
+                    : -(PRInt32)PR_IntervalToMilliseconds(timer->mTimeout-now))
+                  );
+          }
+#endif
+
+          // We are going to let the call to PostTimerEvent here handle the
+          // release of the timer so that we don't end up releasing the timer
+          // on the TimerThread instead of on the thread it targets.
+          timer->PostTimerEvent();
+          timer = nsnull;
+
+          lock.lock();
+          if (mShutdown)
+            break;
+
+          // Update now, as PostTimerEvent plus the locking may have taken a
+          // tick or two, and we may goto next below.
+          now = PR_IntervalNow();
+        }
+      }
+
+      if (mTimers.Count() > 0) {
+        timer = NS_STATIC_CAST(nsTimerImpl *, mTimers[0]);
+
+        PRIntervalTime timeout = timer->mTimeout + mTimeoutAdjustment;
+
+        // Don't wait at all (even for PR_INTERVAL_NO_WAIT) if the next timer
+        // is due now or overdue.
+        if (!TIMER_LESS_THAN(now, timeout))
+          goto next;
+        waitFor = timeout - now;
+      }
+
+#ifdef DEBUG_TIMERS
+      if (PR_LOG_TEST(gTimerLog, PR_LOG_DEBUG)) {
+        if (waitFor == PR_INTERVAL_NO_TIMEOUT)
+          PR_LOG(gTimerLog, PR_LOG_DEBUG,
+                 ("waiting for PR_INTERVAL_NO_TIMEOUT\n"));
+        else
+          PR_LOG(gTimerLog, PR_LOG_DEBUG,
+                 ("waiting for %u\n", PR_IntervalToMilliseconds(waitFor)));
+      }
+#endif
+    }
+
+    mWaiting = PR_TRUE;
+    PR_WaitCondVar(mCondVar, waitFor);
+    mWaiting = PR_FALSE;
+  }
+
+  return NS_OK;
+}
+
+nsresult TimerThread::AddTimer(nsTimerImpl *aTimer)
+{
+  nsAutoLock lock(mLock);
+
+  // Add the timer to our list.
+  PRInt32 i = AddTimerInternal(aTimer);
+  if (i < 0)
+    return NS_ERROR_OUT_OF_MEMORY;
+
+  // Awaken the timer thread.
+  if (mCondVar && mWaiting && i == 0)
+    PR_NotifyCondVar(mCondVar);
+
+  return NS_OK;
+}
+
+nsresult TimerThread::TimerDelayChanged(nsTimerImpl *aTimer)
+{
+  nsAutoLock lock(mLock);
+
+  // Our caller has a strong ref to aTimer, so it can't go away here under
+  // ReleaseTimerInternal.
+  RemoveTimerInternal(aTimer);
+
+  PRInt32 i = AddTimerInternal(aTimer);
+  if (i < 0)
+    return NS_ERROR_OUT_OF_MEMORY;
+
+  // Awaken the timer thread.
+  if (mCondVar && mWaiting && i == 0)
+    PR_NotifyCondVar(mCondVar);
+
+  return NS_OK;
+}
+
+nsresult TimerThread::RemoveTimer(nsTimerImpl *aTimer)
+{
+  nsAutoLock lock(mLock);
+
+  // Remove the timer from our array.  Tell callers that aTimer was not found
+  // by returning NS_ERROR_NOT_AVAILABLE.  Unlike the TimerDelayChanged case
+  // immediately above, our caller may be passing a (now-)weak ref in via the
+  // aTimer param, specifically when nsTimerImpl::Release loses a race with
+  // TimerThread::Run, must wait for the mLock auto-lock here, and during the
+  // wait Run drops the only remaining ref to aTimer via RemoveTimerInternal.
+
+  if (!RemoveTimerInternal(aTimer))
+    return NS_ERROR_NOT_AVAILABLE;
+
+  // Awaken the timer thread.
+  if (mCondVar && mWaiting)
+    PR_NotifyCondVar(mCondVar);
+
+  return NS_OK;
+}
+
+// This function must be called from within a lock
+PRInt32 TimerThread::AddTimerInternal(nsTimerImpl *aTimer)
+{
+  PRIntervalTime now = PR_IntervalNow();
+  PRInt32 count = mTimers.Count();
+  PRInt32 i = 0;
+  for (; i < count; i++) {
+    nsTimerImpl *timer = NS_STATIC_CAST(nsTimerImpl *, mTimers[i]);
+
+    // Don't break till we have skipped any overdue timers.  Do not include
+    // mTimeoutAdjustment here, because we are really trying to avoid calling
+    // TIMER_LESS_THAN(t, u), where the t is now + DELAY_INTERVAL_MAX, u is
+    // now - overdue, and DELAY_INTERVAL_MAX + overdue > DELAY_INTERVAL_LIMIT.
+    // In other words, we want to use now-based time, now adjusted time, even
+    // though "overdue" ultimately depends on adjusted time.
+
+    // XXX does this hold for TYPE_REPEATING_PRECISE?  /be
+
+    if (TIMER_LESS_THAN(now, timer->mTimeout) &&
+        TIMER_LESS_THAN(aTimer->mTimeout, timer->mTimeout)) {
+      break;
+    }
+  }
+
+  if (!mTimers.InsertElementAt(aTimer, i))
+    return -1;
+
+  aTimer->mArmed = PR_TRUE;
+  NS_ADDREF(aTimer);
+  return i;
+}
+
+PRBool TimerThread::RemoveTimerInternal(nsTimerImpl *aTimer)
+{
+  if (!mTimers.RemoveElement(aTimer))
+    return PR_FALSE;
+
+  // Order is crucial here -- see nsTimerImpl::Release.
+  aTimer->mArmed = PR_FALSE;
+  NS_RELEASE(aTimer);
+  return PR_TRUE;
+}
+
+void TimerThread::DoBeforeSleep()
+{
+  mSleeping = PR_TRUE;
+}
+
+void TimerThread::DoAfterSleep()
+{
+  for (PRInt32 i = 0; i < mTimers.Count(); i ++) {
+    nsTimerImpl *timer = NS_STATIC_CAST(nsTimerImpl*, mTimers[i]);
+    // get and set the delay to cause its timeout to be recomputed
+    PRUint32 delay;
+    timer->GetDelay(&delay);
+    timer->SetDelay(delay);
+  }
+
+  // nuke the stored adjustments, so they get recalibrated
+  mTimeoutAdjustment = 0;
+  mDelayLineCounter = 0;
+  mSleeping = PR_FALSE;
+}
+
+
+/* void observe (in nsISupports aSubject, in string aTopic, in wstring aData); */
+NS_IMETHODIMP
+TimerThread::Observe(nsISupports* /* aSubject */, const char *aTopic, const PRUnichar* /* aData */)
+{
+  if (strcmp(aTopic, "sleep_notification") == 0)
+    DoBeforeSleep();
+  else if (strcmp(aTopic, "wake_notification") == 0)
+    DoAfterSleep();
+
+  return NS_OK;
+}