Integrate setTimeout and setInterval with HTML5 event loop

https://bugs.webkit.org/show_bug.cgi?id=203137

Reviewed by Chris Dumez.

This PR integrates DOM timers with HTML5 event loop. Specifically, DOMTimer now uses
EventLoopTaskGroup::scheduleTask and EventLoopTaskGroup::scheduleRepeatingTask instead of
inheriting from SuspendableTimer. This PR also deletes SuspendableTimer class now that
we've migrated all uses of it to EventLoop's equivalents.

* Source/WebCore/Headers.cmake:
* Source/WebCore/Sources.txt:
* Source/WebCore/WebCore.xcodeproj/project.pbxproj:
* Source/WebCore/dom/EventLoop.cpp:
(WebCore::EventLoop::scheduleTask): Fixed a bug that the newly created timer won't be
suspended when the task group had been suspended.
(WebCore::EventLoop::scheduleRepeatingTask): Ditto.
(WebCore::EventLoopTaskGroup::setTimerAlignment):
(WebCore::EventLoopTaskGroup::setTimerHasReachedMaxNestingLevel):
(WebCore::EventLoopTaskGroup::adjustTimerNextTimeout):
(WebCore::EventLoopTaskGroup::adjustTimerRepeatInterval):
(WebCore::EventLoopTaskGroup::didChangeTimerAlignmentInterval):
* Source/WebCore/dom/EventLoop.h:
* Source/WebCore/dom/ScriptExecutionContext.cpp:
(WebCore::ScriptExecutionContext::didChangeTimerAlignmentInterval):
* Source/WebCore/dom/ScriptExecutionContext.h:
* Source/WebCore/dom/TaskSource.h:
* Source/WebCore/page/DOMTimer.cpp:
(WebCore::DOMTimer::DOMTimer):
(WebCore::DOMTimer::removeById):
(WebCore::DOMTimer::fired):
(WebCore::DOMTimer::stop):
(WebCore::DOMTimer::updateTimerIntervalIfNecessary):
(WebCore::DOMTimer::didStop): Deleted.
* Source/WebCore/page/DOMTimer.h:
* Source/WebCore/page/SuspendableTimer.cpp: Removed.
* Source/WebCore/page/SuspendableTimer.h: Removed.
* Source/WebCore/testing/Internals.cpp:
(WebCore::Internals::isTimerThrottled):

Canonical link: https://commits.webkit.org/266828@main

Source/WebCore/Headers.cmake

@@ -1530,7 +1530,6 @@ set(WebCore_PRIVATE_FRAMEWORK_HEADERS
     page/SpeechSynthesisClient.h
     page/StorageBlockingPolicy.h
     page/StructuredSerializeOptions.h
-    page/SuspendableTimer.h
     page/TextDirectionSubmenuInclusionBehavior.h
     page/TextIndicator.h
     page/TranslationContextMenuInfo.h

Source/WebCore/Sources.txt

@@ -1959,7 +1959,6 @@ page/SettingsBase.cpp
 page/ShadowRealmGlobalScope.cpp
 page/ShareDataReader.cpp
 page/SpatialNavigation.cpp
-page/SuspendableTimer.cpp
 page/TextIndicator.cpp
 page/UndoItem.cpp
 page/UndoManager.cpp

Source/WebCore/WebCore.xcodeproj/project.pbxproj

@@ -2439,7 +2439,6 @@
 		626CDE0F1140424C001E5A68 /* SpatialNavigation.h in Headers */ = {isa = PBXBuildFile; fileRef = 626CDE0D1140424C001E5A68 /* SpatialNavigation.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		628D214C12131ED10055DCFC /* NetworkingContext.h in Headers */ = {isa = PBXBuildFile; fileRef = 628D214B12131ED10055DCFC /* NetworkingContext.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		628D214E12131EF40055DCFC /* FrameNetworkingContext.h in Headers */ = {isa = PBXBuildFile; fileRef = 628D214D12131EF40055DCFC /* FrameNetworkingContext.h */; settings = {ATTRIBUTES = (Private, ); }; };
-		62C1217D11AB9E77003C462C /* SuspendableTimer.h in Headers */ = {isa = PBXBuildFile; fileRef = 62C1217B11AB9E77003C462C /* SuspendableTimer.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		62CD325A1157E57C0063B0A7 /* CustomEvent.h in Headers */ = {isa = PBXBuildFile; fileRef = 62CD32571157E57C0063B0A7 /* CustomEvent.h */; };
 		63152D191F9531EE007A5E4B /* ApplicationManifestLoader.h in Headers */ = {isa = PBXBuildFile; fileRef = 63152D171F9531EE007A5E4B /* ApplicationManifestLoader.h */; };
 		63189AE30E83A33300012E41 /* NodeRareData.h in Headers */ = {isa = PBXBuildFile; fileRef = 63189AE20E83A33300012E41 /* NodeRareData.h */; settings = {ATTRIBUTES = (); }; };
@@ -12033,7 +12032,6 @@
 		628D214B12131ED10055DCFC /* NetworkingContext.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = NetworkingContext.h; sourceTree = "<group>"; };
 		628D214D12131EF40055DCFC /* FrameNetworkingContext.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = FrameNetworkingContext.h; sourceTree = "<group>"; };
 		62C1217A11AB9E76003C462C /* SuspendableTimer.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = SuspendableTimer.cpp; sourceTree = "<group>"; };
-		62C1217B11AB9E77003C462C /* SuspendableTimer.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SuspendableTimer.h; sourceTree = "<group>"; };
 		62CD32561157E57C0063B0A7 /* CustomEvent.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = CustomEvent.cpp; sourceTree = "<group>"; };
 		62CD32571157E57C0063B0A7 /* CustomEvent.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = CustomEvent.h; sourceTree = "<group>"; };
 		62CD32581157E57C0063B0A7 /* CustomEvent.idl */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = CustomEvent.idl; sourceTree = "<group>"; };
@@ -26912,8 +26910,6 @@
 				BC4A533625605AE10028C592 /* StorageBlockingPolicy.h */,
 				46FEFBC626DD678200B0C488 /* StructuredSerializeOptions.h */,
 				46FEFBC726DD678300B0C488 /* StructuredSerializeOptions.idl */,
-				62C1217A11AB9E76003C462C /* SuspendableTimer.cpp */,
-				62C1217B11AB9E77003C462C /* SuspendableTimer.h */,
 				BC4A5324256055590028C592 /* TextDirectionSubmenuInclusionBehavior.h */,
 				2D4F96F11A1ECC240098BF88 /* TextIndicator.cpp */,
 				2D4F96F21A1ECC240098BF88 /* TextIndicator.h */,
@@ -41062,7 +41058,6 @@
 				93B2D8160F9920D2006AE6B2 /* SuddenTermination.h in Headers */,
 				97C078501165D5BE003A32EF /* SuffixTree.h in Headers */,
 				97627B9814FB5424002CDCA1 /* Supplementable.h in Headers */,
-				62C1217D11AB9E77003C462C /* SuspendableTimer.h in Headers */,
 				B22279740D00BF220071B782 /* SVGAElement.h in Headers */,
 				24D912B113CA9A1F00D21915 /* SVGAltGlyphDefElement.h in Headers */,
 				65653F2E0D9727D200CA9723 /* SVGAltGlyphElement.h in Headers */,

Source/WebCore/dom/EventLoop.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2019 Apple Inc. All rights reserved.
+ * Copyright (C) 2008-2023 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -28,7 +28,6 @@
 
 #include "Microtasks.h"
 #include "ScriptExecutionContext.h"
-#include "SuspendableTimer.h"
 
 namespace WebCore {
 
@@ -94,6 +93,33 @@ class EventLoopTimer final : public RefCounted<EventLoopTimer>, public TimerBase
         }
     }
 
+    void adjustNextFireTime(Seconds delta)
+    {
+        if (!m_suspended)
+            TimerBase::augmentFireInterval(delta);
+        else if (m_savedIsActive)
+            m_savedNextFireInterval += delta;
+        else {
+            m_savedIsActive = true;
+            m_savedNextFireInterval = delta;
+            m_savedRepeatInterval = 0_s;
+        }
+    }
+
+    void adjustRepeatInterval(Seconds delta)
+    {
+        if (!m_suspended)
+            TimerBase::augmentRepeatInterval(delta);
+        else if (m_savedIsActive) {
+            m_savedNextFireInterval += delta;
+            m_savedRepeatInterval += delta;
+        } else {
+            m_savedIsActive = true;
+            m_savedNextFireInterval = delta;
+            m_savedRepeatInterval = delta;
+        }
+    }
+
 private:
     EventLoopTimer(Type type, std::unique_ptr<EventLoopTask>&& task)
         : m_task(WTFMove(task))
@@ -106,9 +132,10 @@ class EventLoopTimer final : public RefCounted<EventLoopTimer>, public TimerBase
         Ref protectedThis { *this };
         if (!m_task)
             return;
+        WeakPtr group = m_task->group();
         m_task->execute();
-        if (m_type == Type::OneShot)
-            m_task->group()->removeScheduledTimer(*this);
+        if (group && m_type == Type::OneShot)
+            group->removeScheduledTimer(*this);
     }
 
     std::unique_ptr<EventLoopTask> m_task;
@@ -164,6 +191,8 @@ EventLoopTimerHandle EventLoop::scheduleTask(Seconds timeout, std::unique_ptr<Ev
 {
     auto timer = EventLoopTimer::create(EventLoopTimer::Type::OneShot, WTFMove(action));
     timer->startOneShot(timeout);
+    if (timer->group()->isSuspended())
+        timer->suspend();
 
     ASSERT(timer->group());
     timer->group()->didAddTimer(timer);
@@ -183,6 +212,8 @@ EventLoopTimerHandle EventLoop::scheduleRepeatingTask(Seconds nextTimeout, Secon
 {
     auto timer = EventLoopTimer::create(EventLoopTimer::Type::Repeating, WTFMove(action));
     timer->startRepeating(nextTimeout, interval);
+    if (timer->group()->isSuspended())
+        timer->suspend();
 
     ASSERT(timer->group());
     timer->group()->didAddTimer(timer);
@@ -420,6 +451,46 @@ void EventLoopTaskGroup::removeRepeatingTimer(EventLoopTimer& timer)
     m_timers.remove(timer);
 }
 
+void EventLoopTaskGroup::setTimerAlignment(EventLoopTimerHandle handle, TimerAlignment& timerAlignment)
+{
+    if (!handle.m_timer)
+        return;
+    ASSERT(m_timers.contains(*handle.m_timer));
+    handle.m_timer->setTimerAlignment(timerAlignment);
+}
+
+void EventLoopTaskGroup::didChangeTimerAlignmentInterval(EventLoopTimerHandle handle)
+{
+    if (!handle.m_timer)
+        return;
+    ASSERT(m_timers.contains(*handle.m_timer));
+    handle.m_timer->didChangeAlignmentInterval();
+}
+
+void EventLoopTaskGroup::setTimerHasReachedMaxNestingLevel(EventLoopTimerHandle handle, bool value)
+{
+    if (!handle.m_timer)
+        return;
+    ASSERT(m_timers.contains(*handle.m_timer));
+    handle.m_timer->setHasReachedMaxNestingLevel(value);
+}
+
+void EventLoopTaskGroup::adjustTimerNextFireTime(EventLoopTimerHandle handle, Seconds delta)
+{
+    if (!handle.m_timer)
+        return;
+    ASSERT(m_timers.contains(*handle.m_timer));
+    handle.m_timer->adjustNextFireTime(delta);
+}
+
+void EventLoopTaskGroup::adjustTimerRepeatInterval(EventLoopTimerHandle handle, Seconds delta)
+{
+    if (!handle.m_timer)
+        return;
+    ASSERT(m_timers.contains(*handle.m_timer));
+    handle.m_timer->adjustRepeatInterval(delta);
+}
+
 void EventLoopTaskGroup::didAddTimer(EventLoopTimer& timer)
 {
     auto result = m_timers.add(timer);

Source/WebCore/dom/EventLoop.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2019 Apple Inc. All rights reserved.
+ * Copyright (C) 2008-2023 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -40,6 +40,7 @@ class EventLoopTimer;
 class EventTarget;
 class MicrotaskQueue;
 class ScriptExecutionContext;
+class TimerAlignment;
 
 class EventLoopTask {
     WTF_MAKE_NONCOPYABLE(EventLoopTask);
@@ -79,6 +80,7 @@ class EventLoopTimerHandle {
 
 private:
     friend class EventLoop;
+    friend class EventLoopTaskGroup;
 
     void unspecifiedBoolTypeInstance() const { }
 
@@ -208,6 +210,12 @@ class EventLoopTaskGroup : public CanMakeWeakPtr<EventLoopTaskGroup> {
     EventLoopTimerHandle scheduleRepeatingTask(Seconds nextTimeout, Seconds interval, TaskSource, EventLoop::TaskFunction&&);
     void removeRepeatingTimer(EventLoopTimer&);
 
+    void setTimerAlignment(EventLoopTimerHandle, TimerAlignment&);
+    void didChangeTimerAlignmentInterval(EventLoopTimerHandle);
+    void setTimerHasReachedMaxNestingLevel(EventLoopTimerHandle, bool);
+    void adjustTimerNextFireTime(EventLoopTimerHandle, Seconds delta);
+    void adjustTimerRepeatInterval(EventLoopTimerHandle, Seconds delta);
+
     void didAddTimer(EventLoopTimer&);
     void didRemoveTimer(EventLoopTimer&);
 

Source/WebCore/dom/ScriptExecutionContext.cpp

@@ -571,8 +571,9 @@ Seconds ScriptExecutionContext::minimumDOMTimerInterval() const
 
 void ScriptExecutionContext::didChangeTimerAlignmentInterval()
 {
+    auto& eventLoop = this->eventLoop();
     for (auto& timer : m_timeouts.values())
-        timer->didChangeAlignmentInterval();
+        eventLoop.didChangeTimerAlignmentInterval(timer->timer());
 }
 
 Seconds ScriptExecutionContext::domTimerAlignmentInterval(bool) const

Source/WebCore/dom/ScriptExecutionContext.h

@@ -252,7 +252,7 @@ class ScriptExecutionContext : public SecurityContext, public CanMakeCheckedPtr,
     virtual Seconds domTimerAlignmentInterval(bool hasReachedMaxNestingLevel) const;
 
     // TimerAlignment
-    std::optional<MonotonicTime> alignedFireTime(bool hasReachedMaxNestingLevel, MonotonicTime fireTime) const final;
+    WEBCORE_EXPORT std::optional<MonotonicTime> alignedFireTime(bool hasReachedMaxNestingLevel, MonotonicTime fireTime) const final;
 
     virtual EventTarget* errorEventTarget() = 0;
 

Source/WebCore/dom/TaskSource.h

@@ -45,6 +45,7 @@ enum class TaskSource : uint8_t {
     Reporting,
     ScreenWakelock,
     Speech,
+    Timer,
     UserInteraction,
     WebGL,
     WebXR,

Source/WebCore/page/DOMTimer.cpp

@@ -160,7 +160,7 @@ struct NestedTimersMap {
 bool NestedTimersMap::isTrackingNestedTimers = false;
 
 DOMTimer::DOMTimer(ScriptExecutionContext& context, Function<void(ScriptExecutionContext&)>&& action, Seconds interval, Type type)
-    : SuspendableTimerBase(&context)
+    : ActiveDOMObject(&context)
     , m_nestingLevel(context.timerNestingLevel())
     , m_action(WTFMove(action))
     , m_originalInterval(interval)
@@ -169,12 +169,21 @@ DOMTimer::DOMTimer(ScriptExecutionContext& context, Function<void(ScriptExecutio
     , m_currentTimerInterval(intervalClampedToMinimum())
     , m_userGestureTokenToForward(UserGestureIndicator::currentUserGesture())
 {
-    setTimerAlignment(context);
-    setHasReachedMaxNestingLevel(m_nestingLevel >= (m_oneShot ? maxTimerNestingLevelForOneShotTimers : maxTimerNestingLevelForRepeatingTimers));
-    if (m_oneShot)
-        startOneShot(m_currentTimerInterval);
-    else
-        startRepeating(m_originalInterval, m_currentTimerInterval);
+    auto& eventLoop = context.eventLoop();
+    if (m_oneShot) {
+        m_timer = eventLoop.scheduleTask(m_currentTimerInterval, TaskSource::Timer, [weakThis = WeakPtr { *this }] {
+            if (RefPtr strongThis = weakThis.get())
+                strongThis->fired();
+        });
+    } else {
+        m_timer = eventLoop.scheduleRepeatingTask(m_originalInterval, m_currentTimerInterval, TaskSource::Timer, [weakThis = WeakPtr { *this }] {
+            if (RefPtr strongThis = weakThis.get())
+                strongThis->fired();
+        });
+    }
+    eventLoop.setTimerAlignment(m_timer, context);
+    m_hasReachedMaxNestingLevel = m_nestingLevel >= (m_oneShot ? maxTimerNestingLevelForOneShotTimers : maxTimerNestingLevelForRepeatingTimers);
+    eventLoop.setTimerHasReachedMaxNestingLevel(m_timer, m_hasReachedMaxNestingLevel);
 }
 
 DOMTimer::~DOMTimer() = default;
@@ -237,7 +246,8 @@ void DOMTimer::removeById(ScriptExecutionContext& context, int timeoutId)
 
     InspectorInstrumentation::didRemoveTimer(context, timeoutId);
 
-    context.takeTimeout(timeoutId);
+    if (auto timer = context.takeTimeout(timeoutId))
+        timer->m_timer = nullptr;
 }
 
 inline bool DOMTimer::isDOMTimersThrottlingEnabled(const Document& document) const
@@ -297,11 +307,12 @@ void DOMTimer::fired()
     ScriptExecutionContext& context = *scriptExecutionContext();
 
 #if PLATFORM(IOS_FAMILY)
-    if (is<Document>(context)) {
-        auto& document = downcast<Document>(context);
-        if (auto* holdingTank = document.domTimerHoldingTankIfExists(); holdingTank && holdingTank->contains(*this)) {
-            if (m_oneShot)
-                startOneShot(0_s);
+    if (RefPtr document = dynamicDowncast<Document>(context); document && m_oneShot) {
+        if (auto* holdingTank = document->domTimerHoldingTankIfExists(); holdingTank && holdingTank->contains(*this)) {
+            m_timer = document->eventLoop().scheduleTask(0_s, TaskSource::Timer, [weakThis = WeakPtr { *this }] {
+                if (RefPtr strongThis = weakThis.get())
+                    strongThis->fired();
+            });
             return;
         }
     }
@@ -312,7 +323,6 @@ void DOMTimer::fired()
     if (m_userGestureTokenToForward && m_userGestureTokenToForward->hasExpired(UserGestureToken::maximumIntervalForUserGestureForwarding))
         m_userGestureTokenToForward = nullptr;
 
-    ASSERT(!isSuspended());
     ASSERT(!context.activeDOMObjectsAreSuspended());
     UserGestureIndicator gestureIndicator(m_userGestureTokenToForward);
     // Only the first execution of a multi-shot timer should get an affirmative user gesture indicator.
@@ -321,11 +331,11 @@ void DOMTimer::fired()
     InspectorInstrumentation::willFireTimer(context, m_timeoutId, m_oneShot);
 
     // Simple case for non-one-shot timers.
-    if (isActive()) {
-        ASSERT(!m_oneShot);
+    if (!m_oneShot) {
         if (m_nestingLevel < maxTimerNestingLevel) {
             m_nestingLevel++;
-            setHasReachedMaxNestingLevel(m_nestingLevel >= maxTimerNestingLevelForRepeatingTimers);
+            m_hasReachedMaxNestingLevel = m_nestingLevel >= maxTimerNestingLevelForRepeatingTimers;
+            context.eventLoop().setTimerHasReachedMaxNestingLevel(m_timer, m_hasReachedMaxNestingLevel);
             updateTimerIntervalIfNecessary();
         }
 
@@ -356,37 +366,41 @@ void DOMTimer::fired()
     if (nestedTimers) {
         for (auto& idAndTimer : *nestedTimers) {
             auto& timer = idAndTimer.value;
-            if (timer->isActive() && timer->m_oneShot)
+            if (timer->m_oneShot)
                 timer->updateThrottlingStateIfNecessary(fireState);
         }
         nestedTimers->stopTracking();
     }
 }
 
-void DOMTimer::didStop()
+void DOMTimer::stop()
 {
     // Need to release JS objects potentially protected by ScheduledAction
     // because they can form circular references back to the ScriptExecutionContext
     // which will cause a memory leak.
+    m_timer = nullptr;
     m_action = nullptr;
 }
 
 void DOMTimer::updateTimerIntervalIfNecessary()
 {
     ASSERT(m_nestingLevel <= maxTimerNestingLevel);
 
+    if (!scriptExecutionContext())
+        return;
+
     auto previousInterval = m_currentTimerInterval;
     m_currentTimerInterval = intervalClampedToMinimum();
     if (previousInterval == m_currentTimerInterval)
         return;
 
+    ScriptExecutionContext& context = *scriptExecutionContext();
     if (m_oneShot) {
         LOG(DOMTimers, "%p - Updating DOMTimer's fire interval from %.2f ms to %.2f ms due to throttling.", this, previousInterval.milliseconds(), m_currentTimerInterval.milliseconds());
-        augmentFireInterval(m_currentTimerInterval - previousInterval);
+        context.eventLoop().adjustTimerNextFireTime(m_timer, m_currentTimerInterval - previousInterval);
     } else {
-        ASSERT(repeatInterval() == previousInterval);
         LOG(DOMTimers, "%p - Updating DOMTimer's repeat interval from %.2f ms to %.2f ms due to throttling.", this, previousInterval.milliseconds(), m_currentTimerInterval.milliseconds());
-        augmentRepeatInterval(m_currentTimerInterval - previousInterval);
+        context.eventLoop().adjustTimerRepeatInterval(m_timer, m_currentTimerInterval - previousInterval);
     }
 }