| /* |
| * Copyright (C) 2008 Apple Inc. All Rights Reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY |
| * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY |
| * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| */ |
| |
| #pragma once |
| |
| #include "ContextDestructionObserver.h" |
| #include <wtf/Assertions.h> |
| #include <wtf/Forward.h> |
| #include <wtf/RefCounted.h> |
| #include <wtf/Threading.h> |
| |
| namespace WebCore { |
| |
| class ActiveDOMObject : public ContextDestructionObserver { |
| public: |
| // The suspendIfNeeded must be called exactly once after object construction to update |
| // the suspended state to match that of the ScriptExecutionContext. |
| void suspendIfNeeded(); |
| void assertSuspendIfNeededWasCalled() const; |
| |
| virtual bool hasPendingActivity() const; |
| |
| // The canSuspendForDocumentSuspension() function is used by the caller if there is a choice between suspending |
| // and stopping. For example, a page won't be suspended and placed in the back/forward |
| // cache if it contains any objects that cannot be suspended. |
| |
| // However, the suspend function will sometimes be called even if canSuspendForDocumentSuspension() returns false. |
| // That happens in step-by-step JS debugging for example - in this case it would be incorrect |
| // to stop the object. Exact semantics of suspend is up to the object in cases like that. |
| |
| enum ReasonForSuspension { |
| JavaScriptDebuggerPaused, |
| WillDeferLoading, |
| PageCache, |
| PageWillBeSuspended, |
| }; |
| |
| virtual const char* activeDOMObjectName() const = 0; |
| |
| // These three functions must not have a side effect of creating or destroying |
| // any ActiveDOMObject. That means they must not result in calls to arbitrary JavaScript. |
| virtual bool canSuspendForDocumentSuspension() const = 0; // Returning false in canSuspendForDocumentSuspension() will prevent the page from entering the PageCache. |
| virtual void suspend(ReasonForSuspension); |
| virtual void resume(); |
| |
| // This function must not have a side effect of creating an ActiveDOMObject. |
| // That means it must not result in calls to arbitrary JavaScript. |
| // It can, however, have a side effect of deleting an ActiveDOMObject. |
| virtual void stop(); |
| |
| template<class T> void setPendingActivity(T* thisObject) |
| { |
| ASSERT(thisObject == this); |
| thisObject->ref(); |
| ++m_pendingActivityCount; |
| } |
| |
| template<class T> void unsetPendingActivity(T* thisObject) |
| { |
| ASSERT(m_pendingActivityCount > 0); |
| --m_pendingActivityCount; |
| thisObject->deref(); |
| } |
| |
| template<class T> |
| class PendingActivity : public RefCounted<PendingActivity<T>> { |
| public: |
| explicit PendingActivity(T& thisObject) |
| : m_thisObject(thisObject) |
| { |
| ++(m_thisObject->m_pendingActivityCount); |
| } |
| |
| ~PendingActivity() |
| { |
| ASSERT(m_thisObject->m_pendingActivityCount > 0); |
| --(m_thisObject->m_pendingActivityCount); |
| } |
| |
| private: |
| Ref<T> m_thisObject; |
| }; |
| |
| template<class T> Ref<PendingActivity<T>> makePendingActivity(T& thisObject) |
| { |
| ASSERT(&thisObject == this); |
| return adoptRef(*new PendingActivity<T>(thisObject)); |
| } |
| |
| protected: |
| explicit ActiveDOMObject(ScriptExecutionContext*); |
| virtual ~ActiveDOMObject(); |
| |
| private: |
| unsigned m_pendingActivityCount; |
| #if !ASSERT_DISABLED |
| bool m_suspendIfNeededWasCalled; |
| Ref<Thread> m_creationThread { Thread::current() }; |
| #endif |
| }; |
| |
| #if ASSERT_DISABLED |
| |
| inline void ActiveDOMObject::assertSuspendIfNeededWasCalled() const |
| { |
| } |
| |
| #endif |
| |
| } // namespace WebCore |