171 lines
6.5 KiB
C++
171 lines
6.5 KiB
C++
/*
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* Copyright (C) 2008 Apple Inc. All Rights Reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#pragma once
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#include "ContextDestructionObserver.h"
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#include "TaskSource.h"
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#include <wtf/Assertions.h>
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#include <wtf/CancellableTask.h>
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#include <wtf/Forward.h>
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#include <wtf/Function.h>
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#include <wtf/RefCounted.h>
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#include <wtf/Threading.h>
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namespace WebCore {
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class Document;
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class Event;
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class EventLoopTaskGroup;
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class EventTarget;
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enum class ReasonForSuspension {
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JavaScriptDebuggerPaused,
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WillDeferLoading,
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BackForwardCache,
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PageWillBeSuspended,
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};
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class WEBCORE_EXPORT ActiveDOMObject : public ContextDestructionObserver {
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public:
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// The suspendIfNeeded must be called exactly once after object construction to update
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// the suspended state to match that of the ScriptExecutionContext.
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void suspendIfNeeded();
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void assertSuspendIfNeededWasCalled() const;
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// This function is used by JS bindings to determine if the JS wrapper should be kept alive or not.
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bool hasPendingActivity() const { return m_pendingActivityInstanceCount || virtualHasPendingActivity(); }
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// However, the suspend function will sometimes be called even if canSuspendForDocumentSuspension() returns false.
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// That happens in step-by-step JS debugging for example - in this case it would be incorrect
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// to stop the object. Exact semantics of suspend is up to the object in cases like that.
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virtual const char* activeDOMObjectName() const = 0;
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// These functions must not have a side effect of creating or destroying
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// any ActiveDOMObject. That means they must not result in calls to arbitrary JavaScript.
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virtual void suspend(ReasonForSuspension);
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virtual void resume();
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// This function must not have a side effect of creating an ActiveDOMObject.
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// That means it must not result in calls to arbitrary JavaScript.
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// It can, however, have a side effect of deleting an ActiveDOMObject.
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virtual void stop();
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template<class T>
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class PendingActivity : public RefCounted<PendingActivity<T>> {
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public:
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explicit PendingActivity(T& thisObject)
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: m_thisObject(thisObject)
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{
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++(m_thisObject->m_pendingActivityInstanceCount);
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}
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~PendingActivity()
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{
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ASSERT(m_thisObject->m_pendingActivityInstanceCount > 0);
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--(m_thisObject->m_pendingActivityInstanceCount);
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}
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private:
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Ref<T> m_thisObject;
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};
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template<class T> Ref<PendingActivity<T>> makePendingActivity(T& thisObject)
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{
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ASSERT(&thisObject == this);
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return adoptRef(*new PendingActivity<T>(thisObject));
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}
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bool isContextStopped() const;
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bool isAllowedToRunScript() const;
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template<typename T>
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static void queueTaskKeepingObjectAlive(T& object, TaskSource source, Function<void ()>&& task)
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{
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object.queueTaskInEventLoop(source, [protectedObject = makeRef(object), activity = object.ActiveDOMObject::makePendingActivity(object), task = WTFMove(task)] () {
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task();
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});
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}
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template<typename T>
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static void queueCancellableTaskKeepingObjectAlive(T& object, TaskSource source, TaskCancellationGroup& cancellationGroup, Function<void()>&& task)
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{
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CancellableTask cancellableTask(cancellationGroup, WTFMove(task));
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object.queueTaskInEventLoop(source, [protectedObject = makeRef(object), activity = object.ActiveDOMObject::makePendingActivity(object), cancellableTask = WTFMove(cancellableTask)]() mutable {
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cancellableTask();
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});
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}
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template<typename EventTargetType>
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static void queueTaskToDispatchEvent(EventTargetType& target, TaskSource source, Ref<Event>&& event)
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{
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target.queueTaskToDispatchEventInternal(target, source, WTFMove(event));
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}
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template<typename EventTargetType>
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static void queueCancellableTaskToDispatchEvent(EventTargetType& target, TaskSource source, TaskCancellationGroup& cancellationGroup, Ref<Event>&& event)
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{
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target.queueCancellableTaskToDispatchEventInternal(target, source, cancellationGroup, WTFMove(event));
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}
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protected:
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explicit ActiveDOMObject(ScriptExecutionContext*);
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explicit ActiveDOMObject(Document*);
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explicit ActiveDOMObject(Document&);
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virtual ~ActiveDOMObject();
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private:
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enum CheckedScriptExecutionContextType { CheckedScriptExecutionContext };
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ActiveDOMObject(ScriptExecutionContext*, CheckedScriptExecutionContextType);
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// This is used by subclasses to indicate that they have pending activity, meaning that they would
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// like the JS wrapper to stay alive (because they may still fire JS events).
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virtual bool virtualHasPendingActivity() const { return false; }
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void queueTaskInEventLoop(TaskSource, Function<void ()>&&);
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void queueTaskToDispatchEventInternal(EventTarget&, TaskSource, Ref<Event>&&);
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void queueCancellableTaskToDispatchEventInternal(EventTarget&, TaskSource, TaskCancellationGroup&, Ref<Event>&&);
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uint64_t m_pendingActivityInstanceCount { 0 };
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#if ASSERT_ENABLED
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bool m_suspendIfNeededWasCalled { false };
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Ref<Thread> m_creationThread { Thread::current() };
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#endif
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friend class ActiveDOMObjectEventDispatchTask;
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};
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#if !ASSERT_ENABLED
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inline void ActiveDOMObject::assertSuspendIfNeededWasCalled() const
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{
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}
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#endif
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} // namespace WebCore
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