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-rw-r--r--dom/base/TimeoutManager.cpp1338
1 files changed, 1338 insertions, 0 deletions
diff --git a/dom/base/TimeoutManager.cpp b/dom/base/TimeoutManager.cpp
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index 0000000000..1f99f1963d
--- /dev/null
+++ b/dom/base/TimeoutManager.cpp
@@ -0,0 +1,1338 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "TimeoutManager.h"
+#include "nsGlobalWindow.h"
+#include "mozilla/Logging.h"
+#include "mozilla/PerformanceCounter.h"
+#include "mozilla/ProfilerMarkers.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/StaticPrefs_privacy.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/ThrottledEventQueue.h"
+#include "mozilla/TimeStamp.h"
+#include "nsINamed.h"
+#include "mozilla/dom/DocGroup.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/PopupBlocker.h"
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/dom/TimeoutHandler.h"
+#include "TimeoutExecutor.h"
+#include "TimeoutBudgetManager.h"
+#include "mozilla/net/WebSocketEventService.h"
+#include "mozilla/MediaManager.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+LazyLogModule gTimeoutLog("Timeout");
+
+static int32_t gRunningTimeoutDepth = 0;
+
+// static
+const uint32_t TimeoutManager::InvalidFiringId = 0;
+
+namespace {
+double GetRegenerationFactor(bool aIsBackground) {
+ // Lookup function for "dom.timeout.{background,
+ // foreground}_budget_regeneration_rate".
+
+ // Returns the rate of regeneration of the execution budget as a
+ // fraction. If the value is 1.0, the amount of time regenerated is
+ // equal to time passed. At this rate we regenerate 1ms/ms. If it is
+ // 0.01 the amount regenerated is 1% of time passed. At this rate we
+ // regenerate 1ms/100ms, etc.
+ double denominator = std::max(
+ aIsBackground
+ ? StaticPrefs::dom_timeout_background_budget_regeneration_rate()
+ : StaticPrefs::dom_timeout_foreground_budget_regeneration_rate(),
+ 1);
+ return 1.0 / denominator;
+}
+
+TimeDuration GetMaxBudget(bool aIsBackground) {
+ // Lookup function for "dom.timeout.{background,
+ // foreground}_throttling_max_budget".
+
+ // Returns how high a budget can be regenerated before being
+ // clamped. If this value is less or equal to zero,
+ // TimeDuration::Forever() is implied.
+ int32_t maxBudget =
+ aIsBackground
+ ? StaticPrefs::dom_timeout_background_throttling_max_budget()
+ : StaticPrefs::dom_timeout_foreground_throttling_max_budget();
+ return maxBudget > 0 ? TimeDuration::FromMilliseconds(maxBudget)
+ : TimeDuration::Forever();
+}
+
+TimeDuration GetMinBudget(bool aIsBackground) {
+ // The minimum budget is computed by looking up the maximum allowed
+ // delay and computing how long time it would take to regenerate
+ // that budget using the regeneration factor. This number is
+ // expected to be negative.
+ return TimeDuration::FromMilliseconds(
+ -StaticPrefs::dom_timeout_budget_throttling_max_delay() /
+ std::max(
+ aIsBackground
+ ? StaticPrefs::dom_timeout_background_budget_regeneration_rate()
+ : StaticPrefs::dom_timeout_foreground_budget_regeneration_rate(),
+ 1));
+}
+} // namespace
+
+//
+
+bool TimeoutManager::IsBackground() const {
+ return !IsActive() && mWindow.IsBackgroundInternal();
+}
+
+bool TimeoutManager::IsActive() const {
+ // A window is considered active if:
+ // * It is a chrome window
+ // * It is playing audio
+ //
+ // Note that a window can be considered active if it is either in the
+ // foreground or in the background.
+
+ if (mWindow.IsChromeWindow()) {
+ return true;
+ }
+
+ // Check if we're playing audio
+ if (mWindow.IsPlayingAudio()) {
+ return true;
+ }
+
+ return false;
+}
+
+void TimeoutManager::SetLoading(bool value) {
+ // When moving from loading to non-loading, we may need to
+ // reschedule any existing timeouts from the idle timeout queue
+ // to the normal queue.
+ MOZ_LOG(gTimeoutLog, LogLevel::Debug, ("%p: SetLoading(%d)", this, value));
+ if (mIsLoading && !value) {
+ MoveIdleToActive();
+ }
+ // We don't immediately move existing timeouts to the idle queue if we
+ // move to loading. When they would have fired, we'll see we're loading
+ // and move them then.
+ mIsLoading = value;
+}
+
+void TimeoutManager::MoveIdleToActive() {
+ uint32_t num = 0;
+ TimeStamp when;
+ TimeStamp now;
+ // Ensure we maintain the ordering of timeouts, so timeouts
+ // never fire before a timeout set for an earlier time, or
+ // before a timeout for the same time already submitted.
+ // See https://html.spec.whatwg.org/#dom-settimeout #16 and #17
+ while (RefPtr<Timeout> timeout = mIdleTimeouts.GetLast()) {
+ if (num == 0) {
+ when = timeout->When();
+ }
+ timeout->remove();
+ mTimeouts.InsertFront(timeout);
+ if (profiler_thread_is_being_profiled_for_markers()) {
+ if (num == 0) {
+ now = TimeStamp::Now();
+ }
+ TimeDuration elapsed = now - timeout->SubmitTime();
+ TimeDuration target = timeout->When() - timeout->SubmitTime();
+ TimeDuration delta = now - timeout->When();
+ nsPrintfCString marker(
+ "Releasing deferred setTimeout() for %dms (original target time was "
+ "%dms (%dms delta))",
+ int(elapsed.ToMilliseconds()), int(target.ToMilliseconds()),
+ int(delta.ToMilliseconds()));
+ // don't have end before start...
+ PROFILER_MARKER_TEXT(
+ "setTimeout deferred release", DOM,
+ MarkerOptions(
+ MarkerTiming::Interval(
+ delta.ToMilliseconds() >= 0 ? timeout->When() : now, now),
+ MarkerInnerWindowId(mWindow.WindowID())),
+ marker);
+ }
+ num++;
+ }
+ if (num > 0) {
+ MOZ_ALWAYS_SUCCEEDS(MaybeSchedule(when));
+ mIdleExecutor->Cancel();
+ }
+ MOZ_LOG(gTimeoutLog, LogLevel::Debug,
+ ("%p: Moved %d timeouts from Idle to active", this, num));
+}
+
+uint32_t TimeoutManager::CreateFiringId() {
+ uint32_t id = mNextFiringId;
+ mNextFiringId += 1;
+ if (mNextFiringId == InvalidFiringId) {
+ mNextFiringId += 1;
+ }
+
+ mFiringIdStack.AppendElement(id);
+
+ return id;
+}
+
+void TimeoutManager::DestroyFiringId(uint32_t aFiringId) {
+ MOZ_DIAGNOSTIC_ASSERT(!mFiringIdStack.IsEmpty());
+ MOZ_DIAGNOSTIC_ASSERT(mFiringIdStack.LastElement() == aFiringId);
+ mFiringIdStack.RemoveLastElement();
+}
+
+bool TimeoutManager::IsValidFiringId(uint32_t aFiringId) const {
+ return !IsInvalidFiringId(aFiringId);
+}
+
+TimeDuration TimeoutManager::MinSchedulingDelay() const {
+ if (IsActive()) {
+ return TimeDuration();
+ }
+
+ bool isBackground = mWindow.IsBackgroundInternal();
+
+ // If a window isn't active as defined by TimeoutManager::IsActive()
+ // and we're throttling timeouts using an execution budget, we
+ // should adjust the minimum scheduling delay if we have used up all
+ // of our execution budget. Note that a window can be active or
+ // inactive regardless of wether it is in the foreground or in the
+ // background. Throttling using a budget depends largely on the
+ // regeneration factor, which can be specified separately for
+ // foreground and background windows.
+ //
+ // The value that we compute is the time in the future when we again
+ // have a positive execution budget. We do this by taking the
+ // execution budget into account, which if it positive implies that
+ // we have time left to execute, and if it is negative implies that
+ // we should throttle it until the budget again is positive. The
+ // factor used is the rate of budget regeneration.
+ //
+ // We clamp the delay to be less than or equal to
+ // "dom.timeout.budget_throttling_max_delay" to not entirely starve
+ // the timeouts.
+ //
+ // Consider these examples assuming we should throttle using
+ // budgets:
+ //
+ // mExecutionBudget is 20ms
+ // factor is 1, which is 1 ms/ms
+ // delay is 0ms
+ // then we will compute the minimum delay:
+ // max(0, - 20 * 1) = 0
+ //
+ // mExecutionBudget is -50ms
+ // factor is 0.1, which is 1 ms/10ms
+ // delay is 1000ms
+ // then we will compute the minimum delay:
+ // max(1000, - (- 50) * 1/0.1) = max(1000, 500) = 1000
+ //
+ // mExecutionBudget is -15ms
+ // factor is 0.01, which is 1 ms/100ms
+ // delay is 1000ms
+ // then we will compute the minimum delay:
+ // max(1000, - (- 15) * 1/0.01) = max(1000, 1500) = 1500
+ TimeDuration unthrottled =
+ isBackground ? TimeDuration::FromMilliseconds(
+ StaticPrefs::dom_min_background_timeout_value())
+ : TimeDuration();
+ bool budgetThrottlingEnabled = BudgetThrottlingEnabled(isBackground);
+ if (budgetThrottlingEnabled && mExecutionBudget < TimeDuration()) {
+ // Only throttle if execution budget is less than 0
+ double factor = 1.0 / GetRegenerationFactor(mWindow.IsBackgroundInternal());
+ return TimeDuration::Max(unthrottled, -mExecutionBudget.MultDouble(factor));
+ }
+ if (!budgetThrottlingEnabled && isBackground) {
+ return TimeDuration::FromMilliseconds(
+ StaticPrefs::
+ dom_min_background_timeout_value_without_budget_throttling());
+ }
+
+ return unthrottled;
+}
+
+nsresult TimeoutManager::MaybeSchedule(const TimeStamp& aWhen,
+ const TimeStamp& aNow) {
+ MOZ_DIAGNOSTIC_ASSERT(mExecutor);
+
+ // Before we can schedule the executor we need to make sure that we
+ // have an updated execution budget.
+ UpdateBudget(aNow);
+ return mExecutor->MaybeSchedule(aWhen, MinSchedulingDelay());
+}
+
+bool TimeoutManager::IsInvalidFiringId(uint32_t aFiringId) const {
+ // Check the most common ways to invalidate a firing id first.
+ // These should be quite fast.
+ if (aFiringId == InvalidFiringId || mFiringIdStack.IsEmpty()) {
+ return true;
+ }
+
+ if (mFiringIdStack.Length() == 1) {
+ return mFiringIdStack[0] != aFiringId;
+ }
+
+ // Next do a range check on the first and last items in the stack
+ // of active firing ids. This is a bit slower.
+ uint32_t low = mFiringIdStack[0];
+ uint32_t high = mFiringIdStack.LastElement();
+ MOZ_DIAGNOSTIC_ASSERT(low != high);
+ if (low > high) {
+ // If the first element is bigger than the last element in the
+ // stack, that means mNextFiringId wrapped around to zero at
+ // some point.
+ std::swap(low, high);
+ }
+ MOZ_DIAGNOSTIC_ASSERT(low < high);
+
+ if (aFiringId < low || aFiringId > high) {
+ return true;
+ }
+
+ // Finally, fall back to verifying the firing id is not anywhere
+ // in the stack. This could be slow for a large stack, but that
+ // should be rare. It can only happen with deeply nested event
+ // loop spinning. For example, a page that does a lot of timers
+ // and a lot of sync XHRs within those timers could be slow here.
+ return !mFiringIdStack.Contains(aFiringId);
+}
+
+TimeDuration TimeoutManager::CalculateDelay(Timeout* aTimeout) const {
+ MOZ_DIAGNOSTIC_ASSERT(aTimeout);
+ TimeDuration result = aTimeout->mInterval;
+
+ if (aTimeout->mNestingLevel >=
+ StaticPrefs::dom_clamp_timeout_nesting_level_AtStartup()) {
+ uint32_t minTimeoutValue = StaticPrefs::dom_min_timeout_value();
+ result = TimeDuration::Max(result,
+ TimeDuration::FromMilliseconds(minTimeoutValue));
+ }
+
+ return result;
+}
+
+PerformanceCounter* TimeoutManager::GetPerformanceCounter() {
+ Document* doc = mWindow.GetDocument();
+ if (doc) {
+ dom::DocGroup* docGroup = doc->GetDocGroup();
+ if (docGroup) {
+ return docGroup->GetPerformanceCounter();
+ }
+ }
+ return nullptr;
+}
+
+void TimeoutManager::RecordExecution(Timeout* aRunningTimeout,
+ Timeout* aTimeout) {
+ TimeoutBudgetManager& budgetManager = TimeoutBudgetManager::Get();
+ TimeStamp now = TimeStamp::Now();
+
+ if (aRunningTimeout) {
+ // If we're running a timeout callback, record any execution until
+ // now.
+ TimeDuration duration = budgetManager.RecordExecution(now, aRunningTimeout);
+
+ UpdateBudget(now, duration);
+
+ // This is an ad-hoc way to use the counters for the timers
+ // that should be removed at somepoint. See Bug 1482834
+ PerformanceCounter* counter = GetPerformanceCounter();
+ if (counter) {
+ counter->IncrementExecutionDuration(duration.ToMicroseconds());
+ }
+ }
+
+ if (aTimeout) {
+ // If we're starting a new timeout callback, start recording.
+ budgetManager.StartRecording(now);
+ PerformanceCounter* counter = GetPerformanceCounter();
+ if (counter) {
+ counter->IncrementDispatchCounter(DispatchCategory(TaskCategory::Timer));
+ }
+ } else {
+ // Else stop by clearing the start timestamp.
+ budgetManager.StopRecording();
+ }
+}
+
+void TimeoutManager::UpdateBudget(const TimeStamp& aNow,
+ const TimeDuration& aDuration) {
+ if (mWindow.IsChromeWindow()) {
+ return;
+ }
+
+ // The budget is adjusted by increasing it with the time since the
+ // last budget update factored with the regeneration rate. If a
+ // runnable has executed, subtract that duration from the
+ // budget. The budget updated without consideration of wether the
+ // window is active or not. If throttling is enabled and the window
+ // is active and then becomes inactive, an overdrawn budget will
+ // still be counted against the minimum delay.
+ bool isBackground = mWindow.IsBackgroundInternal();
+ if (BudgetThrottlingEnabled(isBackground)) {
+ double factor = GetRegenerationFactor(isBackground);
+ TimeDuration regenerated = (aNow - mLastBudgetUpdate).MultDouble(factor);
+ // Clamp the budget to the range of minimum and maximum allowed budget.
+ mExecutionBudget = TimeDuration::Max(
+ GetMinBudget(isBackground),
+ TimeDuration::Min(GetMaxBudget(isBackground),
+ mExecutionBudget - aDuration + regenerated));
+ } else {
+ // If budget throttling isn't enabled, reset the execution budget
+ // to the max budget specified in preferences. Always doing this
+ // will catch the case of BudgetThrottlingEnabled going from
+ // returning true to returning false. This prevent us from looping
+ // in RunTimeout, due to totalTimeLimit being set to zero and no
+ // timeouts being executed, even though budget throttling isn't
+ // active at the moment.
+ mExecutionBudget = GetMaxBudget(isBackground);
+ }
+
+ mLastBudgetUpdate = aNow;
+}
+
+// The longest interval (as PRIntervalTime) we permit, or that our
+// timer code can handle, really. See DELAY_INTERVAL_LIMIT in
+// nsTimerImpl.h for details.
+#define DOM_MAX_TIMEOUT_VALUE DELAY_INTERVAL_LIMIT
+
+uint32_t TimeoutManager::sNestingLevel = 0;
+
+TimeoutManager::TimeoutManager(nsGlobalWindowInner& aWindow,
+ uint32_t aMaxIdleDeferMS)
+ : mWindow(aWindow),
+ mExecutor(new TimeoutExecutor(this, false, 0)),
+ mIdleExecutor(new TimeoutExecutor(this, true, aMaxIdleDeferMS)),
+ mTimeouts(*this),
+ mTimeoutIdCounter(1),
+ mNextFiringId(InvalidFiringId + 1),
+#ifdef DEBUG
+ mFiringIndex(0),
+ mLastFiringIndex(-1),
+#endif
+ mRunningTimeout(nullptr),
+ mIdleTimeouts(*this),
+ mIdleCallbackTimeoutCounter(1),
+ mLastBudgetUpdate(TimeStamp::Now()),
+ mExecutionBudget(GetMaxBudget(mWindow.IsBackgroundInternal())),
+ mThrottleTimeouts(false),
+ mThrottleTrackingTimeouts(false),
+ mBudgetThrottleTimeouts(false),
+ mIsLoading(false) {
+ MOZ_LOG(gTimeoutLog, LogLevel::Debug,
+ ("TimeoutManager %p created, tracking bucketing %s\n", this,
+ StaticPrefs::privacy_trackingprotection_annotate_channels()
+ ? "enabled"
+ : "disabled"));
+}
+
+TimeoutManager::~TimeoutManager() {
+ MOZ_DIAGNOSTIC_ASSERT(mWindow.IsDying());
+ MOZ_DIAGNOSTIC_ASSERT(!mThrottleTimeoutsTimer);
+
+ mExecutor->Shutdown();
+ mIdleExecutor->Shutdown();
+
+ MOZ_LOG(gTimeoutLog, LogLevel::Debug,
+ ("TimeoutManager %p destroyed\n", this));
+}
+
+uint32_t TimeoutManager::GetTimeoutId(Timeout::Reason aReason) {
+ switch (aReason) {
+ case Timeout::Reason::eIdleCallbackTimeout:
+ return ++mIdleCallbackTimeoutCounter;
+ case Timeout::Reason::eTimeoutOrInterval:
+ return ++mTimeoutIdCounter;
+ case Timeout::Reason::eDelayedWebTaskTimeout:
+ default:
+ return std::numeric_limits<uint32_t>::max(); // no cancellation support
+ }
+}
+
+bool TimeoutManager::IsRunningTimeout() const { return mRunningTimeout; }
+
+nsresult TimeoutManager::SetTimeout(TimeoutHandler* aHandler, int32_t interval,
+ bool aIsInterval, Timeout::Reason aReason,
+ int32_t* aReturn) {
+ // If we don't have a document (we could have been unloaded since
+ // the call to setTimeout was made), do nothing.
+ nsCOMPtr<Document> doc = mWindow.GetExtantDoc();
+ if (!doc || mWindow.IsDying()) {
+ return NS_OK;
+ }
+
+ // Disallow negative intervals.
+ interval = std::max(0, interval);
+
+ // Make sure we don't proceed with an interval larger than our timer
+ // code can handle. (Note: we already forced |interval| to be non-negative,
+ // so the uint32_t cast (to avoid compiler warnings) is ok.)
+ uint32_t maxTimeoutMs = PR_IntervalToMilliseconds(DOM_MAX_TIMEOUT_VALUE);
+ if (static_cast<uint32_t>(interval) > maxTimeoutMs) {
+ interval = maxTimeoutMs;
+ }
+
+ RefPtr<Timeout> timeout = new Timeout();
+#ifdef DEBUG
+ timeout->mFiringIndex = -1;
+#endif
+ timeout->mWindow = &mWindow;
+ timeout->mIsInterval = aIsInterval;
+ timeout->mInterval = TimeDuration::FromMilliseconds(interval);
+ timeout->mScriptHandler = aHandler;
+ timeout->mReason = aReason;
+
+ // No popups from timeouts by default
+ timeout->mPopupState = PopupBlocker::openAbused;
+
+ // XXX: Does eIdleCallbackTimeout need clamping?
+ if (aReason == Timeout::Reason::eTimeoutOrInterval ||
+ aReason == Timeout::Reason::eIdleCallbackTimeout) {
+ timeout->mNestingLevel =
+ sNestingLevel < StaticPrefs::dom_clamp_timeout_nesting_level_AtStartup()
+ ? sNestingLevel + 1
+ : sNestingLevel;
+ }
+
+ // Now clamp the actual interval we will use for the timer based on
+ TimeDuration realInterval = CalculateDelay(timeout);
+ TimeStamp now = TimeStamp::Now();
+ timeout->SetWhenOrTimeRemaining(now, realInterval);
+
+ // If we're not suspended, then set the timer.
+ if (!mWindow.IsSuspended()) {
+ nsresult rv = MaybeSchedule(timeout->When(), now);
+ if (NS_FAILED(rv)) {
+ return rv;
+ }
+ }
+
+ if (gRunningTimeoutDepth == 0 &&
+ PopupBlocker::GetPopupControlState() < PopupBlocker::openBlocked) {
+ // This timeout is *not* set from another timeout and it's set
+ // while popups are enabled. Propagate the state to the timeout if
+ // its delay (interval) is equal to or less than what
+ // "dom.disable_open_click_delay" is set to (in ms).
+
+ // This is checking |interval|, not realInterval, on purpose,
+ // because our lower bound for |realInterval| could be pretty high
+ // in some cases.
+ if (interval <= StaticPrefs::dom_disable_open_click_delay()) {
+ timeout->mPopupState = PopupBlocker::GetPopupControlState();
+ }
+ }
+
+ Timeouts::SortBy sort(mWindow.IsFrozen() ? Timeouts::SortBy::TimeRemaining
+ : Timeouts::SortBy::TimeWhen);
+
+ timeout->mTimeoutId = GetTimeoutId(aReason);
+ mTimeouts.Insert(timeout, sort);
+
+ *aReturn = timeout->mTimeoutId;
+
+ MOZ_LOG(
+ gTimeoutLog, LogLevel::Debug,
+ ("Set%s(TimeoutManager=%p, timeout=%p, delay=%i, "
+ "minimum=%f, throttling=%s, state=%s(%s), realInterval=%f) "
+ "returned timeout ID %u, budget=%d\n",
+ aIsInterval ? "Interval" : "Timeout", this, timeout.get(), interval,
+ (CalculateDelay(timeout) - timeout->mInterval).ToMilliseconds(),
+ mThrottleTimeouts ? "yes" : (mThrottleTimeoutsTimer ? "pending" : "no"),
+ IsActive() ? "active" : "inactive",
+ mWindow.IsBackgroundInternal() ? "background" : "foreground",
+ realInterval.ToMilliseconds(), timeout->mTimeoutId,
+ int(mExecutionBudget.ToMilliseconds())));
+
+ return NS_OK;
+}
+
+// Make sure we clear it no matter which list it's in
+void TimeoutManager::ClearTimeout(int32_t aTimerId, Timeout::Reason aReason) {
+ if (ClearTimeoutInternal(aTimerId, aReason, false) ||
+ mIdleTimeouts.IsEmpty()) {
+ return; // no need to check the other list if we cleared the timeout
+ }
+ ClearTimeoutInternal(aTimerId, aReason, true);
+}
+
+bool TimeoutManager::ClearTimeoutInternal(int32_t aTimerId,
+ Timeout::Reason aReason,
+ bool aIsIdle) {
+ MOZ_ASSERT(aReason == Timeout::Reason::eTimeoutOrInterval ||
+ aReason == Timeout::Reason::eIdleCallbackTimeout,
+ "This timeout reason doesn't support cancellation.");
+
+ uint32_t timerId = (uint32_t)aTimerId;
+ Timeouts& timeouts = aIsIdle ? mIdleTimeouts : mTimeouts;
+ RefPtr<TimeoutExecutor>& executor = aIsIdle ? mIdleExecutor : mExecutor;
+ bool deferredDeletion = false;
+
+ Timeout* timeout = timeouts.GetTimeout(timerId, aReason);
+ if (!timeout) {
+ return false;
+ }
+ bool firstTimeout = timeout == timeouts.GetFirst();
+
+ MOZ_LOG(gTimeoutLog, LogLevel::Debug,
+ ("%s(TimeoutManager=%p, timeout=%p, ID=%u)\n",
+ timeout->mReason == Timeout::Reason::eIdleCallbackTimeout
+ ? "CancelIdleCallback"
+ : timeout->mIsInterval ? "ClearInterval"
+ : "ClearTimeout",
+ this, timeout, timeout->mTimeoutId));
+
+ if (timeout->mRunning) {
+ /* We're running from inside the timeout. Mark this
+ timeout for deferred deletion by the code in
+ RunTimeout() */
+ timeout->mIsInterval = false;
+ deferredDeletion = true;
+ } else {
+ /* Delete the aTimeout from the pending aTimeout list */
+ timeout->remove();
+ }
+
+ // We don't need to reschedule the executor if any of the following are true:
+ // * If the we weren't cancelling the first timeout, then the executor's
+ // state doesn't need to change. It will only reflect the next soonest
+ // Timeout.
+ // * If we did cancel the first Timeout, but its currently running, then
+ // RunTimeout() will handle rescheduling the executor.
+ // * If the window has become suspended then we should not start executing
+ // Timeouts.
+ if (!firstTimeout || deferredDeletion || mWindow.IsSuspended()) {
+ return true;
+ }
+
+ // Stop the executor and restart it at the next soonest deadline.
+ executor->Cancel();
+
+ Timeout* nextTimeout = timeouts.GetFirst();
+ if (nextTimeout) {
+ if (aIsIdle) {
+ MOZ_ALWAYS_SUCCEEDS(
+ executor->MaybeSchedule(nextTimeout->When(), TimeDuration(0)));
+ } else {
+ MOZ_ALWAYS_SUCCEEDS(MaybeSchedule(nextTimeout->When()));
+ }
+ }
+ return true;
+}
+
+void TimeoutManager::RunTimeout(const TimeStamp& aNow,
+ const TimeStamp& aTargetDeadline,
+ bool aProcessIdle) {
+ MOZ_DIAGNOSTIC_ASSERT(!aNow.IsNull());
+ MOZ_DIAGNOSTIC_ASSERT(!aTargetDeadline.IsNull());
+
+ MOZ_ASSERT_IF(mWindow.IsFrozen(), mWindow.IsSuspended());
+ if (mWindow.IsSuspended()) {
+ return;
+ }
+
+ Timeouts& timeouts(aProcessIdle ? mIdleTimeouts : mTimeouts);
+
+ // Limit the overall time spent in RunTimeout() to reduce jank.
+ uint32_t totalTimeLimitMS =
+ std::max(1u, StaticPrefs::dom_timeout_max_consecutive_callbacks_ms());
+ const TimeDuration totalTimeLimit =
+ TimeDuration::Min(TimeDuration::FromMilliseconds(totalTimeLimitMS),
+ TimeDuration::Max(TimeDuration(), mExecutionBudget));
+
+ // Allow up to 25% of our total time budget to be used figuring out which
+ // timers need to run. This is the initial loop in this method.
+ const TimeDuration initialTimeLimit =
+ TimeDuration::FromMilliseconds(totalTimeLimit.ToMilliseconds() / 4);
+
+ // Ammortize overhead from from calling TimeStamp::Now() in the initial
+ // loop, though, by only checking for an elapsed limit every N timeouts.
+ const uint32_t kNumTimersPerInitialElapsedCheck = 100;
+
+ // Start measuring elapsed time immediately. We won't potentially expire
+ // the time budget until at least one Timeout has run, though.
+ TimeStamp now(aNow);
+ TimeStamp start = now;
+
+ uint32_t firingId = CreateFiringId();
+ auto guard = MakeScopeExit([&] { DestroyFiringId(firingId); });
+
+ // Make sure that the window and the script context don't go away as
+ // a result of running timeouts
+ RefPtr<nsGlobalWindowInner> window(&mWindow);
+ // Accessing members of mWindow here is safe, because the lifetime of
+ // TimeoutManager is the same as the lifetime of the containing
+ // nsGlobalWindow.
+
+ // A native timer has gone off. See which of our timeouts need
+ // servicing
+ TimeStamp deadline;
+
+ if (aTargetDeadline > now) {
+ // The OS timer fired early (which can happen due to the timers
+ // having lower precision than TimeStamp does). Set |deadline| to
+ // be the time when the OS timer *should* have fired so that any
+ // timers that *should* have fired *will* be fired now.
+
+ deadline = aTargetDeadline;
+ } else {
+ deadline = now;
+ }
+
+ TimeStamp nextDeadline;
+ uint32_t numTimersToRun = 0;
+
+ // The timeout list is kept in deadline order. Discover the latest timeout
+ // whose deadline has expired. On some platforms, native timeout events fire
+ // "early", but we handled that above by setting deadline to aTargetDeadline
+ // if the timer fired early. So we can stop walking if we get to timeouts
+ // whose When() is greater than deadline, since once that happens we know
+ // nothing past that point is expired.
+
+ for (Timeout* timeout = timeouts.GetFirst(); timeout != nullptr;
+ timeout = timeout->getNext()) {
+ if (totalTimeLimit.IsZero() || timeout->When() > deadline) {
+ nextDeadline = timeout->When();
+ break;
+ }
+
+ if (IsInvalidFiringId(timeout->mFiringId)) {
+ // Mark any timeouts that are on the list to be fired with the
+ // firing depth so that we can reentrantly run timeouts
+ timeout->mFiringId = firingId;
+
+ numTimersToRun += 1;
+
+ // Run only a limited number of timers based on the configured maximum.
+ if (numTimersToRun % kNumTimersPerInitialElapsedCheck == 0) {
+ now = TimeStamp::Now();
+ TimeDuration elapsed(now - start);
+ if (elapsed >= initialTimeLimit) {
+ nextDeadline = timeout->When();
+ break;
+ }
+ }
+ }
+ }
+ if (aProcessIdle) {
+ MOZ_LOG(
+ gTimeoutLog, LogLevel::Debug,
+ ("Running %u deferred timeouts on idle (TimeoutManager=%p), "
+ "nextDeadline = %gms from now",
+ numTimersToRun, this,
+ nextDeadline.IsNull() ? 0.0 : (nextDeadline - now).ToMilliseconds()));
+ }
+
+ now = TimeStamp::Now();
+
+ // Wherever we stopped in the timer list, schedule the executor to
+ // run for the next unexpired deadline. Note, this *must* be done
+ // before we start executing any content script handlers. If one
+ // of them spins the event loop the executor must already be scheduled
+ // in order for timeouts to fire properly.
+ if (!nextDeadline.IsNull()) {
+ // Note, we verified the window is not suspended at the top of
+ // method and the window should not have been suspended while
+ // executing the loop above since it doesn't call out to js.
+ MOZ_DIAGNOSTIC_ASSERT(!mWindow.IsSuspended());
+ if (aProcessIdle) {
+ // We don't want to update timing budget for idle queue firings, and
+ // all timeouts in the IdleTimeouts list have hit their deadlines,
+ // and so should run as soon as possible.
+ MOZ_ALWAYS_SUCCEEDS(
+ mIdleExecutor->MaybeSchedule(nextDeadline, TimeDuration()));
+ } else {
+ MOZ_ALWAYS_SUCCEEDS(MaybeSchedule(nextDeadline, now));
+ }
+ }
+
+ // Maybe the timeout that the event was fired for has been deleted
+ // and there are no others timeouts with deadlines that make them
+ // eligible for execution yet. Go away.
+ if (!numTimersToRun) {
+ return;
+ }
+
+ // Now we need to search the normal and tracking timer list at the same
+ // time to run the timers in the scheduled order.
+
+ // We stop iterating each list when we go past the last expired timeout from
+ // that list that we have observed above. That timeout will either be the
+ // next item after the last timeout we looked at or nullptr if we have
+ // exhausted the entire list while looking for the last expired timeout.
+ {
+ // Use a nested scope in order to make sure the strong references held while
+ // iterating are freed after the loop.
+
+ // The next timeout to run. This is used to advance the loop, but
+ // we cannot set it until we've run the current timeout, since
+ // running the current timeout might remove the immediate next
+ // timeout.
+ RefPtr<Timeout> next;
+
+ for (RefPtr<Timeout> timeout = timeouts.GetFirst(); timeout != nullptr;
+ timeout = next) {
+ next = timeout->getNext();
+ // We should only execute callbacks for the set of expired Timeout
+ // objects we computed above.
+ if (timeout->mFiringId != firingId) {
+ // If the FiringId does not match, but is still valid, then this is
+ // a Timeout for another RunTimeout() on the call stack (such as in
+ // the case of nested event loops, for alert() or more likely XHR).
+ // Just skip it.
+ if (IsValidFiringId(timeout->mFiringId)) {
+ MOZ_LOG(gTimeoutLog, LogLevel::Debug,
+ ("Skipping Run%s(TimeoutManager=%p, timeout=%p) since "
+ "firingId %d is valid (processing firingId %d)"
+#ifdef DEBUG
+ " - FiringIndex %" PRId64 " (mLastFiringIndex %" PRId64 ")"
+#endif
+ ,
+ timeout->mIsInterval ? "Interval" : "Timeout", this,
+ timeout.get(), timeout->mFiringId, firingId
+#ifdef DEBUG
+ ,
+ timeout->mFiringIndex, mFiringIndex
+#endif
+ ));
+#ifdef DEBUG
+ // The old FiringIndex assumed no recursion; recursion can cause
+ // other timers to get fired "in the middle" of a sequence we've
+ // already assigned firingindexes to. Since we're not going to
+ // run this timeout now, remove any FiringIndex that was already
+ // set.
+
+ // Since all timers that have FiringIndexes set *must* be ready
+ // to run and have valid FiringIds, all of them will be 'skipped'
+ // and reset if we recurse - we don't have to look through the
+ // list past where we'll stop on the first InvalidFiringId.
+ timeout->mFiringIndex = -1;
+#endif
+ continue;
+ }
+
+ // If, however, the FiringId is invalid then we have reached Timeout
+ // objects beyond the list we calculated above. This can happen
+ // if the Timeout just beyond our last expired Timeout is cancelled
+ // by one of the callbacks we've just executed. In this case we
+ // should just stop iterating. We're done.
+ else {
+ break;
+ }
+ }
+
+ MOZ_ASSERT_IF(mWindow.IsFrozen(), mWindow.IsSuspended());
+ if (mWindow.IsSuspended()) {
+ break;
+ }
+
+ // The timeout is on the list to run at this depth, go ahead and
+ // process it.
+
+ // Record the first time we try to fire a timeout, and ensure that
+ // all actual firings occur in that order. This ensures that we
+ // retain compliance with the spec language
+ // (https://html.spec.whatwg.org/#dom-settimeout) specifically items
+ // 15 ("If method context is a Window object, wait until the Document
+ // associated with method context has been fully active for a further
+ // timeout milliseconds (not necessarily consecutively)") and item 16
+ // ("Wait until any invocations of this algorithm that had the same
+ // method context, that started before this one, and whose timeout is
+ // equal to or less than this one's, have completed.").
+#ifdef DEBUG
+ if (timeout->mFiringIndex == -1) {
+ timeout->mFiringIndex = mFiringIndex++;
+ }
+#endif
+
+ if (mIsLoading && !aProcessIdle) {
+ // Any timeouts that would fire during a load will be deferred
+ // until the load event occurs, but if there's an idle time,
+ // they'll be run before the load event.
+ timeout->remove();
+ // MOZ_RELEASE_ASSERT(timeout->When() <= (TimeStamp::Now()));
+ mIdleTimeouts.InsertBack(timeout);
+ if (MOZ_LOG_TEST(gTimeoutLog, LogLevel::Debug)) {
+ uint32_t num = 0;
+ for (Timeout* t = mIdleTimeouts.GetFirst(); t != nullptr;
+ t = t->getNext()) {
+ num++;
+ }
+ MOZ_LOG(
+ gTimeoutLog, LogLevel::Debug,
+ ("Deferring Run%s(TimeoutManager=%p, timeout=%p (%gms in the "
+ "past)) (%u deferred)",
+ timeout->mIsInterval ? "Interval" : "Timeout", this,
+ timeout.get(), (now - timeout->When()).ToMilliseconds(), num));
+ }
+ MOZ_ALWAYS_SUCCEEDS(mIdleExecutor->MaybeSchedule(now, TimeDuration()));
+ } else {
+ // Get the script context (a strong ref to prevent it going away)
+ // for this timeout and ensure the script language is enabled.
+ nsCOMPtr<nsIScriptContext> scx = mWindow.GetContextInternal();
+
+ if (!scx) {
+ // No context means this window was closed or never properly
+ // initialized for this language. This timer will never fire
+ // so just remove it.
+ timeout->remove();
+ continue;
+ }
+
+#ifdef DEBUG
+ if (timeout->mFiringIndex <= mLastFiringIndex) {
+ MOZ_LOG(gTimeoutLog, LogLevel::Debug,
+ ("Incorrect firing index for Run%s(TimeoutManager=%p, "
+ "timeout=%p) with "
+ "firingId %d - FiringIndex %" PRId64
+ " (mLastFiringIndex %" PRId64 ")",
+ timeout->mIsInterval ? "Interval" : "Timeout", this,
+ timeout.get(), timeout->mFiringId, timeout->mFiringIndex,
+ mFiringIndex));
+ }
+ MOZ_ASSERT(timeout->mFiringIndex > mLastFiringIndex);
+ mLastFiringIndex = timeout->mFiringIndex;
+#endif
+ // This timeout is good to run.
+ bool timeout_was_cleared = window->RunTimeoutHandler(timeout, scx);
+ MOZ_LOG(gTimeoutLog, LogLevel::Debug,
+ ("Run%s(TimeoutManager=%p, timeout=%p) returned %d\n",
+ timeout->mIsInterval ? "Interval" : "Timeout", this,
+ timeout.get(), !!timeout_was_cleared));
+
+ if (timeout_was_cleared) {
+ // Make sure we're not holding any Timeout objects alive.
+ next = nullptr;
+
+ // Since ClearAllTimeouts() was called the lists should be empty.
+ MOZ_DIAGNOSTIC_ASSERT(!HasTimeouts());
+
+ return;
+ }
+
+ // If we need to reschedule a setInterval() the delay should be
+ // calculated based on when its callback started to execute. So
+ // save off the last time before updating our "now" timestamp to
+ // account for its callback execution time.
+ TimeStamp lastCallbackTime = now;
+ now = TimeStamp::Now();
+
+ // If we have a regular interval timer, we re-schedule the
+ // timeout, accounting for clock drift.
+ bool needsReinsertion =
+ RescheduleTimeout(timeout, lastCallbackTime, now);
+
+ // Running a timeout can cause another timeout to be deleted, so
+ // we need to reset the pointer to the following timeout.
+ next = timeout->getNext();
+
+ timeout->remove();
+
+ if (needsReinsertion) {
+ // Insert interval timeout onto the corresponding list sorted in
+ // deadline order. AddRefs timeout.
+ // Always re-insert into the normal time queue!
+ mTimeouts.Insert(timeout, mWindow.IsFrozen()
+ ? Timeouts::SortBy::TimeRemaining
+ : Timeouts::SortBy::TimeWhen);
+ }
+ }
+ // Check to see if we have run out of time to execute timeout handlers.
+ // If we've exceeded our time budget then terminate the loop immediately.
+ TimeDuration elapsed = now - start;
+ if (elapsed >= totalTimeLimit) {
+ // We ran out of time. Make sure to schedule the executor to
+ // run immediately for the next timer, if it exists. Its possible,
+ // however, that the last timeout handler suspended the window. If
+ // that happened then we must skip this step.
+ if (!mWindow.IsSuspended()) {
+ if (next) {
+ if (aProcessIdle) {
+ // We don't want to update timing budget for idle queue firings,
+ // and all timeouts in the IdleTimeouts list have hit their
+ // deadlines, and so should run as soon as possible.
+
+ // Shouldn't need cancelling since it never waits
+ MOZ_ALWAYS_SUCCEEDS(
+ mIdleExecutor->MaybeSchedule(next->When(), TimeDuration()));
+ } else {
+ // If we ran out of execution budget we need to force a
+ // reschedule. By cancelling the executor we will not run
+ // immediately, but instead reschedule to the minimum
+ // scheduling delay.
+ if (mExecutionBudget < TimeDuration()) {
+ mExecutor->Cancel();
+ }
+
+ MOZ_ALWAYS_SUCCEEDS(MaybeSchedule(next->When(), now));
+ }
+ }
+ }
+ break;
+ }
+ }
+ }
+}
+
+bool TimeoutManager::RescheduleTimeout(Timeout* aTimeout,
+ const TimeStamp& aLastCallbackTime,
+ const TimeStamp& aCurrentNow) {
+ MOZ_DIAGNOSTIC_ASSERT(aLastCallbackTime <= aCurrentNow);
+
+ if (!aTimeout->mIsInterval) {
+ return false;
+ }
+
+ // Automatically increase the nesting level when a setInterval()
+ // is rescheduled just as if it was using a chained setTimeout().
+ if (aTimeout->mNestingLevel <
+ StaticPrefs::dom_clamp_timeout_nesting_level_AtStartup()) {
+ aTimeout->mNestingLevel += 1;
+ }
+
+ // Compute time to next timeout for interval timer.
+ // Make sure nextInterval is at least CalculateDelay().
+ TimeDuration nextInterval = CalculateDelay(aTimeout);
+
+ TimeStamp firingTime = aLastCallbackTime + nextInterval;
+ TimeDuration delay = firingTime - aCurrentNow;
+
+#ifdef DEBUG
+ aTimeout->mFiringIndex = -1;
+#endif
+ // And make sure delay is nonnegative; that might happen if the timer
+ // thread is firing our timers somewhat early or if they're taking a long
+ // time to run the callback.
+ if (delay < TimeDuration(0)) {
+ delay = TimeDuration(0);
+ }
+
+ aTimeout->SetWhenOrTimeRemaining(aCurrentNow, delay);
+
+ if (mWindow.IsSuspended()) {
+ return true;
+ }
+
+ nsresult rv = MaybeSchedule(aTimeout->When(), aCurrentNow);
+ NS_ENSURE_SUCCESS(rv, false);
+
+ return true;
+}
+
+void TimeoutManager::ClearAllTimeouts() {
+ bool seenRunningTimeout = false;
+
+ MOZ_LOG(gTimeoutLog, LogLevel::Debug,
+ ("ClearAllTimeouts(TimeoutManager=%p)\n", this));
+
+ if (mThrottleTimeoutsTimer) {
+ mThrottleTimeoutsTimer->Cancel();
+ mThrottleTimeoutsTimer = nullptr;
+ }
+
+ mExecutor->Cancel();
+ mIdleExecutor->Cancel();
+
+ ForEachUnorderedTimeout([&](Timeout* aTimeout) {
+ /* If RunTimeout() is higher up on the stack for this
+ window, e.g. as a result of document.write from a timeout,
+ then we need to reset the list insertion point for
+ newly-created timeouts in case the user adds a timeout,
+ before we pop the stack back to RunTimeout. */
+ if (mRunningTimeout == aTimeout) {
+ seenRunningTimeout = true;
+ }
+
+ // Set timeout->mCleared to true to indicate that the timeout was
+ // cleared and taken out of the list of timeouts
+ aTimeout->mCleared = true;
+ });
+
+ // Clear out our lists
+ mTimeouts.Clear();
+ mIdleTimeouts.Clear();
+}
+
+void TimeoutManager::Timeouts::Insert(Timeout* aTimeout, SortBy aSortBy) {
+ // Start at mLastTimeout and go backwards. Stop if we see a Timeout with a
+ // valid FiringId since those timers are currently being processed by
+ // RunTimeout. This optimizes for the common case of insertion at the end.
+ Timeout* prevSibling;
+ for (prevSibling = GetLast();
+ prevSibling &&
+ // This condition needs to match the one in SetTimeoutOrInterval that
+ // determines whether to set When() or TimeRemaining().
+ (aSortBy == SortBy::TimeRemaining
+ ? prevSibling->TimeRemaining() > aTimeout->TimeRemaining()
+ : prevSibling->When() > aTimeout->When()) &&
+ // Check the firing ID last since it will evaluate true in the vast
+ // majority of cases.
+ mManager.IsInvalidFiringId(prevSibling->mFiringId);
+ prevSibling = prevSibling->getPrevious()) {
+ /* Do nothing; just searching */
+ }
+
+ // Now link in aTimeout after prevSibling.
+ if (prevSibling) {
+ aTimeout->SetTimeoutContainer(mTimeouts);
+ prevSibling->setNext(aTimeout);
+ } else {
+ InsertFront(aTimeout);
+ }
+
+ aTimeout->mFiringId = InvalidFiringId;
+}
+
+Timeout* TimeoutManager::BeginRunningTimeout(Timeout* aTimeout) {
+ Timeout* currentTimeout = mRunningTimeout;
+ mRunningTimeout = aTimeout;
+ ++gRunningTimeoutDepth;
+
+ RecordExecution(currentTimeout, aTimeout);
+ return currentTimeout;
+}
+
+void TimeoutManager::EndRunningTimeout(Timeout* aTimeout) {
+ --gRunningTimeoutDepth;
+
+ RecordExecution(mRunningTimeout, aTimeout);
+ mRunningTimeout = aTimeout;
+}
+
+void TimeoutManager::UnmarkGrayTimers() {
+ ForEachUnorderedTimeout([](Timeout* aTimeout) {
+ if (aTimeout->mScriptHandler) {
+ aTimeout->mScriptHandler->MarkForCC();
+ }
+ });
+}
+
+void TimeoutManager::Suspend() {
+ MOZ_LOG(gTimeoutLog, LogLevel::Debug, ("Suspend(TimeoutManager=%p)\n", this));
+
+ if (mThrottleTimeoutsTimer) {
+ mThrottleTimeoutsTimer->Cancel();
+ mThrottleTimeoutsTimer = nullptr;
+ }
+
+ mExecutor->Cancel();
+ mIdleExecutor->Cancel();
+}
+
+void TimeoutManager::Resume() {
+ MOZ_LOG(gTimeoutLog, LogLevel::Debug, ("Resume(TimeoutManager=%p)\n", this));
+
+ // When Suspend() has been called after IsDocumentLoaded(), but the
+ // throttle tracking timer never managed to fire, start the timer
+ // again.
+ if (mWindow.IsDocumentLoaded() && !mThrottleTimeouts) {
+ MaybeStartThrottleTimeout();
+ }
+
+ Timeout* nextTimeout = mTimeouts.GetFirst();
+ if (nextTimeout) {
+ MOZ_ALWAYS_SUCCEEDS(MaybeSchedule(nextTimeout->When()));
+ }
+ nextTimeout = mIdleTimeouts.GetFirst();
+ if (nextTimeout) {
+ MOZ_ALWAYS_SUCCEEDS(
+ mIdleExecutor->MaybeSchedule(nextTimeout->When(), TimeDuration()));
+ }
+}
+
+void TimeoutManager::Freeze() {
+ MOZ_LOG(gTimeoutLog, LogLevel::Debug, ("Freeze(TimeoutManager=%p)\n", this));
+
+ TimeStamp now = TimeStamp::Now();
+ ForEachUnorderedTimeout([&](Timeout* aTimeout) {
+ // Save the current remaining time for this timeout. We will
+ // re-apply it when the window is Thaw()'d. This effectively
+ // shifts timers to the right as if time does not pass while
+ // the window is frozen.
+ TimeDuration delta(0);
+ if (aTimeout->When() > now) {
+ delta = aTimeout->When() - now;
+ }
+ aTimeout->SetWhenOrTimeRemaining(now, delta);
+ MOZ_DIAGNOSTIC_ASSERT(aTimeout->TimeRemaining() == delta);
+ });
+}
+
+void TimeoutManager::Thaw() {
+ MOZ_LOG(gTimeoutLog, LogLevel::Debug, ("Thaw(TimeoutManager=%p)\n", this));
+
+ TimeStamp now = TimeStamp::Now();
+
+ ForEachUnorderedTimeout([&](Timeout* aTimeout) {
+ // Set When() back to the time when the timer is supposed to fire.
+ aTimeout->SetWhenOrTimeRemaining(now, aTimeout->TimeRemaining());
+ MOZ_DIAGNOSTIC_ASSERT(!aTimeout->When().IsNull());
+ });
+}
+
+void TimeoutManager::UpdateBackgroundState() {
+ mExecutionBudget = GetMaxBudget(mWindow.IsBackgroundInternal());
+
+ // When the window moves to the background or foreground we should
+ // reschedule the TimeoutExecutor in case the MinSchedulingDelay()
+ // changed. Only do this if the window is not suspended and we
+ // actually have a timeout.
+ if (!mWindow.IsSuspended()) {
+ Timeout* nextTimeout = mTimeouts.GetFirst();
+ if (nextTimeout) {
+ mExecutor->Cancel();
+ MOZ_ALWAYS_SUCCEEDS(MaybeSchedule(nextTimeout->When()));
+ }
+ // the Idle queue should all be past their firing time, so there we just
+ // need to restart the queue
+
+ // XXX May not be needed if we don't stop the idle queue, as
+ // MinSchedulingDelay isn't relevant here
+ nextTimeout = mIdleTimeouts.GetFirst();
+ if (nextTimeout) {
+ mIdleExecutor->Cancel();
+ MOZ_ALWAYS_SUCCEEDS(
+ mIdleExecutor->MaybeSchedule(nextTimeout->When(), TimeDuration()));
+ }
+ }
+}
+
+namespace {
+
+class ThrottleTimeoutsCallback final : public nsITimerCallback,
+ public nsINamed {
+ public:
+ explicit ThrottleTimeoutsCallback(nsGlobalWindowInner* aWindow)
+ : mWindow(aWindow) {}
+
+ NS_DECL_ISUPPORTS
+ NS_DECL_NSITIMERCALLBACK
+
+ NS_IMETHOD GetName(nsACString& aName) override {
+ aName.AssignLiteral("ThrottleTimeoutsCallback");
+ return NS_OK;
+ }
+
+ private:
+ ~ThrottleTimeoutsCallback() = default;
+
+ private:
+ // The strong reference here keeps the Window and hence the TimeoutManager
+ // object itself alive.
+ RefPtr<nsGlobalWindowInner> mWindow;
+};
+
+NS_IMPL_ISUPPORTS(ThrottleTimeoutsCallback, nsITimerCallback, nsINamed)
+
+NS_IMETHODIMP
+ThrottleTimeoutsCallback::Notify(nsITimer* aTimer) {
+ mWindow->TimeoutManager().StartThrottlingTimeouts();
+ mWindow = nullptr;
+ return NS_OK;
+}
+
+} // namespace
+
+bool TimeoutManager::BudgetThrottlingEnabled(bool aIsBackground) const {
+ // A window can be throttled using budget if
+ // * It isn't active
+ // * If it isn't using WebRTC
+ // * If it hasn't got open WebSockets
+ // * If it hasn't got active IndexedDB databases
+
+ // Note that we allow both foreground and background to be
+ // considered for budget throttling. What determines if they are if
+ // budget throttling is enabled is the max budget.
+ if ((aIsBackground
+ ? StaticPrefs::dom_timeout_background_throttling_max_budget()
+ : StaticPrefs::dom_timeout_foreground_throttling_max_budget()) < 0) {
+ return false;
+ }
+
+ if (!mBudgetThrottleTimeouts || IsActive()) {
+ return false;
+ }
+
+ // Check if there are any active IndexedDB databases
+ if (mWindow.HasActiveIndexedDBDatabases()) {
+ return false;
+ }
+
+ // Check if we have active PeerConnection
+ if (mWindow.HasActivePeerConnections()) {
+ return false;
+ }
+
+ if (mWindow.HasOpenWebSockets()) {
+ return false;
+ }
+
+ return true;
+}
+
+void TimeoutManager::StartThrottlingTimeouts() {
+ MOZ_ASSERT(NS_IsMainThread());
+ MOZ_DIAGNOSTIC_ASSERT(mThrottleTimeoutsTimer);
+
+ MOZ_LOG(gTimeoutLog, LogLevel::Debug,
+ ("TimeoutManager %p started to throttle tracking timeouts\n", this));
+
+ MOZ_DIAGNOSTIC_ASSERT(!mThrottleTimeouts);
+ mThrottleTimeouts = true;
+ mThrottleTrackingTimeouts = true;
+ mBudgetThrottleTimeouts =
+ StaticPrefs::dom_timeout_enable_budget_timer_throttling();
+ mThrottleTimeoutsTimer = nullptr;
+}
+
+void TimeoutManager::OnDocumentLoaded() {
+ // The load event may be firing again if we're coming back to the page by
+ // navigating through the session history, so we need to ensure to only call
+ // this when mThrottleTimeouts hasn't been set yet.
+ if (!mThrottleTimeouts) {
+ MaybeStartThrottleTimeout();
+ }
+}
+
+void TimeoutManager::MaybeStartThrottleTimeout() {
+ if (StaticPrefs::dom_timeout_throttling_delay() <= 0 || mWindow.IsDying() ||
+ mWindow.IsSuspended()) {
+ return;
+ }
+
+ MOZ_DIAGNOSTIC_ASSERT(!mThrottleTimeouts);
+
+ MOZ_LOG(gTimeoutLog, LogLevel::Debug,
+ ("TimeoutManager %p delaying tracking timeout throttling by %dms\n",
+ this, StaticPrefs::dom_timeout_throttling_delay()));
+
+ nsCOMPtr<nsITimerCallback> callback = new ThrottleTimeoutsCallback(&mWindow);
+
+ NS_NewTimerWithCallback(getter_AddRefs(mThrottleTimeoutsTimer), callback,
+ StaticPrefs::dom_timeout_throttling_delay(),
+ nsITimer::TYPE_ONE_SHOT, EventTarget());
+}
+
+void TimeoutManager::BeginSyncOperation() {
+ // If we're beginning a sync operation, the currently running
+ // timeout will be put on hold. To not get into an inconsistent
+ // state, where the currently running timeout appears to take time
+ // equivalent to the period of us spinning up a new event loop,
+ // record what we have and stop recording until we reach
+ // EndSyncOperation.
+ RecordExecution(mRunningTimeout, nullptr);
+}
+
+void TimeoutManager::EndSyncOperation() {
+ // If we're running a timeout, restart the measurement from here.
+ RecordExecution(nullptr, mRunningTimeout);
+}
+
+nsIEventTarget* TimeoutManager::EventTarget() {
+ return mWindow.GetBrowsingContextGroup()->GetTimerEventQueue();
+}