1 /* 2 * Copyright (C) 2008 Apple Inc. All Rights Reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR 17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 * 25 */ 26 27 #ifndef ActiveDOMObject_h 28 #define ActiveDOMObject_h 29 30 #include <wtf/Assertions.h> 31 32 namespace WebCore { 33 34 class ScriptExecutionContext; 35 36 class ActiveDOMObject { 37 public: 38 ActiveDOMObject(ScriptExecutionContext*, void* upcastPointer); 39 scriptExecutionContext()40 ScriptExecutionContext* scriptExecutionContext() const { return m_scriptExecutionContext; } 41 virtual bool hasPendingActivity() const; 42 43 virtual void contextDestroyed(); 44 45 // canSuspend() is used by the caller if there is a choice between suspending and stopping. 46 // For example, a page won't be suspended and placed in the back/forward cache if it has 47 // the objects that can not be suspended. 48 // However, 'suspend' can be called even if canSuspend() would return 'false'. That 49 // happens in step-by-step JS debugging for example - in this case it would be incorrect 50 // to stop the object. Exact semantics of suspend is up to the object then. 51 enum ReasonForSuspension { 52 JavaScriptDebuggerPaused, 53 WillShowDialog, 54 DocumentWillBecomeInactive 55 }; 56 virtual bool canSuspend() const; 57 virtual void suspend(ReasonForSuspension); 58 virtual void resume(); 59 virtual void stop(); 60 setPendingActivity(T * thisObject)61 template<class T> void setPendingActivity(T* thisObject) 62 { 63 ASSERT(thisObject == this); 64 thisObject->ref(); 65 m_pendingActivityCount++; 66 } 67 unsetPendingActivity(T * thisObject)68 template<class T> void unsetPendingActivity(T* thisObject) 69 { 70 ASSERT(m_pendingActivityCount > 0); 71 --m_pendingActivityCount; 72 thisObject->deref(); 73 } 74 75 protected: 76 virtual ~ActiveDOMObject(); 77 78 private: 79 ScriptExecutionContext* m_scriptExecutionContext; 80 unsigned m_pendingActivityCount; 81 }; 82 83 } // namespace WebCore 84 85 #endif // ActiveDOMObject_h 86