mozilla
/
gecko-dev
зеркало из https://github.com/mozilla/gecko-dev.git
1
0
Форкнуть 0
Код Задачи Пакеты Проекты Релизы Вики Активность
gecko-dev/dom/base/TimeoutManager.cpp

1288 строки
42 KiB
C++
Исходник Ответственный История

/* -*- 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 "nsContentUtils.h"
#include "nsGlobalWindow.h"
#include "mozilla/Logging.h"
#include "mozilla/PerformanceCounter.h"
#include "mozilla/StaticPrefs.h"
#include "mozilla/Telemetry.h"
#include "mozilla/ThrottledEventQueue.h"
#include "mozilla/TimeStamp.h"
#include "nsIDocShell.h"
#include "nsINamed.h"
#include "nsITimeoutHandler.h"
#include "mozilla/dom/DocGroup.h"
#include "mozilla/dom/TabGroup.h"
#include "TimeoutExecutor.h"
#include "TimeoutBudgetManager.h"
#include "mozilla/net/WebSocketEventService.h"
#include "mozilla/MediaManager.h"
using namespace mozilla;
using namespace mozilla::dom;
static LazyLogModule gLog("Timeout");
static int32_t gRunningTimeoutDepth = 0;
// The default shortest interval/timeout we permit
#define DEFAULT_MIN_CLAMP_TIMEOUT_VALUE 4 // 4ms
#define DEFAULT_MIN_BACKGROUND_TIMEOUT_VALUE 1000 // 1000ms
#define DEFAULT_MIN_TRACKING_TIMEOUT_VALUE 4 // 4ms
#define DEFAULT_MIN_TRACKING_BACKGROUND_TIMEOUT_VALUE 1000 // 1000ms
static int32_t gMinClampTimeoutValue = 0;
static int32_t gMinBackgroundTimeoutValue = 0;
static int32_t gMinTrackingTimeoutValue = 0;
static int32_t gMinTrackingBackgroundTimeoutValue = 0;
static int32_t gTimeoutThrottlingDelay = 0;
static bool gAnnotateTrackingChannels = false;
#define DEFAULT_BACKGROUND_BUDGET_REGENERATION_FACTOR 100 // 1ms per 100ms
#define DEFAULT_FOREGROUND_BUDGET_REGENERATION_FACTOR 1 // 1ms per 1ms
#define DEFAULT_BACKGROUND_THROTTLING_MAX_BUDGET 50 // 50ms
#define DEFAULT_FOREGROUND_THROTTLING_MAX_BUDGET -1 // infinite
#define DEFAULT_BUDGET_THROTTLING_MAX_DELAY 15000 // 15s
#define DEFAULT_ENABLE_BUDGET_TIMEOUT_THROTTLING false
static int32_t gBackgroundBudgetRegenerationFactor = 0;
static int32_t gForegroundBudgetRegenerationFactor = 0;
static int32_t gBackgroundThrottlingMaxBudget = 0;
static int32_t gForegroundThrottlingMaxBudget = 0;
static int32_t gBudgetThrottlingMaxDelay = 0;
static bool gEnableBudgetTimeoutThrottling = false;
// 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 ? gBackgroundBudgetRegenerationFactor
: gForegroundBudgetRegenerationFactor,
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 ? gBackgroundThrottlingMaxBudget
: gForegroundThrottlingMaxBudget;
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(
- gBudgetThrottlingMaxDelay /
std::max(aIsBackground ? gBackgroundBudgetRegenerationFactor
: gForegroundBudgetRegenerationFactor,
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.AsInner()->IsPlayingAudio()) {
return true;
}
return false;
}
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
// gBudgetThrottlingMaxDelay 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(gMinBackgroundTimeoutValue)
: TimeDuration();
if (BudgetThrottlingEnabled(isBackground) &&
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));
}
//
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.
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);
}
// The number of nested timeouts before we start clamping. HTML5 says 1, WebKit
// uses 5.
#define DOM_CLAMP_TIMEOUT_NESTING_LEVEL 5u
TimeDuration
TimeoutManager::CalculateDelay(Timeout* aTimeout) const {
MOZ_DIAGNOSTIC_ASSERT(aTimeout);
TimeDuration result = aTimeout->mInterval;
if (aTimeout->mNestingLevel >= DOM_CLAMP_TIMEOUT_NESTING_LEVEL) {
result = TimeDuration::Max(
result, TimeDuration::FromMilliseconds(gMinClampTimeoutValue));
}
return result;
}
PerformanceCounter*
TimeoutManager::GetPerformanceCounter()
{
if (!StaticPrefs::dom_performance_enable_scheduler_timing()) {
return nullptr;
}
nsIDocument* doc = mWindow.GetDocument();
if (doc) {
dom::DocGroup* docGroup = doc->GetDocGroup();
if (docGroup) {
return docGroup->GetPerformanceCounter();
}
}
return nullptr;
}
void
TimeoutManager::RecordExecution(Timeout* aRunningTimeout,
Timeout* aTimeout)
{
if (!StaticPrefs::dom_performance_enable_scheduler_timing() &&
mWindow.IsChromeWindow()) {
return;
}
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;
}
#define DEFAULT_TIMEOUT_THROTTLING_DELAY -1 // Only positive integers cause us to introduce a delay for
// timeout throttling.
// 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;
namespace {
// The maximum number of milliseconds to allow consecutive timer callbacks
// to run in a single event loop runnable.
#define DEFAULT_MAX_CONSECUTIVE_CALLBACKS_MILLISECONDS 4
uint32_t gMaxConsecutiveCallbacksMilliseconds;
// Only propagate the open window click permission if the setTimeout() is equal
// to or less than this value.
#define DEFAULT_DISABLE_OPEN_CLICK_DELAY 0
int32_t gDisableOpenClickDelay;
} // anonymous namespace
TimeoutManager::TimeoutManager(nsGlobalWindowInner& aWindow)
: mWindow(aWindow),
mExecutor(new TimeoutExecutor(this)),
mTimeouts(*this),
mTimeoutIdCounter(1),
mNextFiringId(InvalidFiringId + 1),
mRunningTimeout(nullptr),
mIdleCallbackTimeoutCounter(1),
mLastBudgetUpdate(TimeStamp::Now()),
mExecutionBudget(GetMaxBudget(mWindow.IsBackgroundInternal())),
mThrottleTimeouts(false),
mThrottleTrackingTimeouts(false),
mBudgetThrottleTimeouts(false)
{
MOZ_LOG(gLog, LogLevel::Debug,
("TimeoutManager %p created, tracking bucketing %s\n",
this, gAnnotateTrackingChannels ? "enabled" : "disabled"));
}
TimeoutManager::~TimeoutManager()
{
MOZ_DIAGNOSTIC_ASSERT(mWindow.IsDying());
MOZ_DIAGNOSTIC_ASSERT(!mThrottleTimeoutsTimer);
mExecutor->Shutdown();
MOZ_LOG(gLog, LogLevel::Debug,
("TimeoutManager %p destroyed\n", this));
}
/* static */
void
TimeoutManager::Initialize()
{
Preferences::AddIntVarCache(&gMinClampTimeoutValue,
"dom.min_timeout_value",
DEFAULT_MIN_CLAMP_TIMEOUT_VALUE);
Preferences::AddIntVarCache(&gMinBackgroundTimeoutValue,
"dom.min_background_timeout_value",
DEFAULT_MIN_BACKGROUND_TIMEOUT_VALUE);
Preferences::AddIntVarCache(&gMinTrackingTimeoutValue,
"dom.min_tracking_timeout_value",
DEFAULT_MIN_TRACKING_TIMEOUT_VALUE);
Preferences::AddIntVarCache(&gMinTrackingBackgroundTimeoutValue,
"dom.min_tracking_background_timeout_value",
DEFAULT_MIN_TRACKING_BACKGROUND_TIMEOUT_VALUE);
Preferences::AddIntVarCache(&gTimeoutThrottlingDelay,
"dom.timeout.throttling_delay",
DEFAULT_TIMEOUT_THROTTLING_DELAY);
Preferences::AddBoolVarCache(&gAnnotateTrackingChannels,
"privacy.trackingprotection.annotate_channels",
false);
Preferences::AddUintVarCache(&gMaxConsecutiveCallbacksMilliseconds,
"dom.timeout.max_consecutive_callbacks_ms",
DEFAULT_MAX_CONSECUTIVE_CALLBACKS_MILLISECONDS);
Preferences::AddIntVarCache(&gDisableOpenClickDelay,
"dom.disable_open_click_delay",
DEFAULT_DISABLE_OPEN_CLICK_DELAY);
Preferences::AddIntVarCache(&gBackgroundBudgetRegenerationFactor,
"dom.timeout.background_budget_regeneration_rate",
DEFAULT_BACKGROUND_BUDGET_REGENERATION_FACTOR);
Preferences::AddIntVarCache(&gForegroundBudgetRegenerationFactor,
"dom.timeout.foreground_budget_regeneration_rate",
DEFAULT_FOREGROUND_BUDGET_REGENERATION_FACTOR);
Preferences::AddIntVarCache(&gBackgroundThrottlingMaxBudget,
"dom.timeout.background_throttling_max_budget",
DEFAULT_BACKGROUND_THROTTLING_MAX_BUDGET);
Preferences::AddIntVarCache(&gForegroundThrottlingMaxBudget,
"dom.timeout.foreground_throttling_max_budget",
DEFAULT_FOREGROUND_THROTTLING_MAX_BUDGET);
Preferences::AddIntVarCache(&gBudgetThrottlingMaxDelay,
"dom.timeout.budget_throttling_max_delay",
DEFAULT_BUDGET_THROTTLING_MAX_DELAY);
Preferences::AddBoolVarCache(&gEnableBudgetTimeoutThrottling,
"dom.timeout.enable_budget_timer_throttling",
DEFAULT_ENABLE_BUDGET_TIMEOUT_THROTTLING);
}
uint32_t
TimeoutManager::GetTimeoutId(Timeout::Reason aReason)
{
switch (aReason) {
case Timeout::Reason::eIdleCallbackTimeout:
return ++mIdleCallbackTimeoutCounter;
case Timeout::Reason::eTimeoutOrInterval:
default:
return ++mTimeoutIdCounter;
}
}
bool
TimeoutManager::IsRunningTimeout() const
{
return mRunningTimeout;
}
nsresult
TimeoutManager::SetTimeout(nsITimeoutHandler* 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<nsIDocument> doc = mWindow.GetExtantDoc();
if (!doc) {
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();
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 = openAbused;
timeout->mNestingLevel = sNestingLevel < DOM_CLAMP_TIMEOUT_NESTING_LEVEL
? 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 &&
nsContentUtils::GetPopupControlState() < 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 <= gDisableOpenClickDelay) {
timeout->mPopupState = nsContentUtils::GetPopupControlState();
}
}
Timeouts::SortBy sort(mWindow.IsFrozen() ? Timeouts::SortBy::TimeRemaining
: Timeouts::SortBy::TimeWhen);
mTimeouts.Insert(timeout, sort);
timeout->mTimeoutId = GetTimeoutId(aReason);
*aReturn = timeout->mTimeoutId;
MOZ_LOG(gLog,
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;
}
void
TimeoutManager::ClearTimeout(int32_t aTimerId, Timeout::Reason aReason)
{
uint32_t timerId = (uint32_t)aTimerId;
bool firstTimeout = true;
bool deferredDeletion = false;
mTimeouts.ForEachAbortable([&](Timeout* aTimeout) {
MOZ_LOG(gLog, LogLevel::Debug,
("Clear%s(TimeoutManager=%p, timeout=%p, aTimerId=%u, ID=%u)\n", aTimeout->mIsInterval ? "Interval" : "Timeout",
this, aTimeout, timerId, aTimeout->mTimeoutId));
if (aTimeout->mTimeoutId == timerId && aTimeout->mReason == aReason) {
if (aTimeout->mRunning) {
/* We're running from inside the aTimeout. Mark this
aTimeout for deferred deletion by the code in
RunTimeout() */
aTimeout->mIsInterval = false;
deferredDeletion = true;
}
else {
/* Delete the aTimeout from the pending aTimeout list */
aTimeout->remove();
}
return true; // abort!
}
firstTimeout = false;
return false;
});
// 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;
}
// Stop the executor and restart it at the next soonest deadline.
mExecutor->Cancel();
Timeout* nextTimeout = mTimeouts.GetFirst();
if (nextTimeout) {
MOZ_ALWAYS_SUCCEEDS(MaybeSchedule(nextTimeout->When()));
}
}
void
TimeoutManager::RunTimeout(const TimeStamp& aNow, const TimeStamp& aTargetDeadline)
{
MOZ_DIAGNOSTIC_ASSERT(!aNow.IsNull());
MOZ_DIAGNOSTIC_ASSERT(!aTargetDeadline.IsNull());
MOZ_ASSERT_IF(mWindow.IsFrozen(), mWindow.IsSuspended());
if (mWindow.IsSuspended()) {
return;
}
// Limit the overall time spent in RunTimeout() to reduce jank.
uint32_t totalTimeLimitMS = std::max(1u, gMaxConsecutiveCallbacksMilliseconds);
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
nsCOMPtr<nsIScriptGlobalObject> windowKungFuDeathGrip(&mWindow);
// Silence the static analysis error about windowKungFuDeathGrip. Accessing
// members of mWindow here is safe, because the lifetime of TimeoutManager is
// the same as the lifetime of the containing nsGlobalWindow.
Unused << windowKungFuDeathGrip;
// 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 = mTimeouts.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;
}
}
}
}
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());
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 = mTimeouts.GetFirst();
timeout != nullptr;
timeout = next) {
// 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. Just
// skip it.
if (IsValidFiringId(timeout->mFiringId)) {
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.
// 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;
}
// This timeout is good to run
bool timeout_was_cleared = mWindow.RunTimeoutHandler(timeout, scx);
MOZ_LOG(
gLog,
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.
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 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 < DOM_CLAMP_TIMEOUT_NESTING_LEVEL) {
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;
// 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(gLog, LogLevel::Debug,
("ClearAllTimeouts(TimeoutManager=%p)\n", this));
if (mThrottleTimeoutsTimer) {
mThrottleTimeoutsTimer->Cancel();
mThrottleTimeoutsTimer = nullptr;
}
mExecutor->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 list
mTimeouts.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) {
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(gLog, LogLevel::Debug,
("Suspend(TimeoutManager=%p)\n", this));
if (mThrottleTimeoutsTimer) {
mThrottleTimeoutsTimer->Cancel();
mThrottleTimeoutsTimer = nullptr;
}
mExecutor->Cancel();
}
void
TimeoutManager::Resume()
{
MOZ_LOG(gLog, 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.AsInner()->IsDocumentLoaded() && !mThrottleTimeouts) {
MaybeStartThrottleTimeout();
}
Timeout* nextTimeout = mTimeouts.GetFirst();
if (nextTimeout) {
MOZ_ALWAYS_SUCCEEDS(MaybeSchedule(nextTimeout->When()));
}
}
void
TimeoutManager::Freeze()
{
MOZ_LOG(gLog, 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(gLog, 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()));
}
}
}
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() {}
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->AsInner()->TimeoutManager().StartThrottlingTimeouts();
mWindow = nullptr;
return NS_OK;
}
}
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 ? gBackgroundThrottlingMaxBudget
: gForegroundThrottlingMaxBudget) < 0) {
return false;
}
if (!mBudgetThrottleTimeouts || IsActive()) {
return false;
}
// Check if there are any active IndexedDB databases
if (mWindow.AsInner()->HasActiveIndexedDBDatabases()) {
return false;
}
// Check if we have active PeerConnection
if (mWindow.AsInner()->HasActivePeerConnections()) {
return false;
}
if (mWindow.AsInner()->HasOpenWebSockets()) {
return false;
}
return true;
}
void
TimeoutManager::StartThrottlingTimeouts()
{
MOZ_ASSERT(NS_IsMainThread());
MOZ_DIAGNOSTIC_ASSERT(mThrottleTimeoutsTimer);
MOZ_LOG(gLog, LogLevel::Debug,
("TimeoutManager %p started to throttle tracking timeouts\n", this));
MOZ_DIAGNOSTIC_ASSERT(!mThrottleTimeouts);
mThrottleTimeouts = true;
mThrottleTrackingTimeouts = true;
mBudgetThrottleTimeouts = gEnableBudgetTimeoutThrottling;
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 (gTimeoutThrottlingDelay <= 0 ||
mWindow.IsDying() || mWindow.IsSuspended()) {
return;
}
MOZ_DIAGNOSTIC_ASSERT(!mThrottleTimeouts);
MOZ_LOG(gLog, LogLevel::Debug,
("TimeoutManager %p delaying tracking timeout throttling by %dms\n",
this, gTimeoutThrottlingDelay));
nsCOMPtr<nsITimerCallback> callback =
new ThrottleTimeoutsCallback(&mWindow);
NS_NewTimerWithCallback(getter_AddRefs(mThrottleTimeoutsTimer),
callback, gTimeoutThrottlingDelay, 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.EventTargetFor(TaskCategory::Timer);
}
Ссылка в новой задаче Показать git blame Копировать постоянную ссылку