WebCore/EventTarget.h

   1 /*
   2  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
   3  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
   4  *           (C) 2001 Dirk Mueller (mueller@kde.org)
   5  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
   6  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
   7  *           (C) 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
  19  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  21  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  22  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  23  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  24  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  25  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  26  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  *
  30  */
  31
  32 #ifndef EventTarget_h
  33 #define EventTarget_h
  34
  35 #include <wtf/Forward.h>
  36
  37 namespace WebCore {
  38
  39     class AtomicString;
  40     class DOMApplicationCache;
  41     class Event;
  42     class EventListener;
  43     class EventTargetNode;
  44     class MessagePort;
  45     class ScriptExecutionContext;
  46     class SVGElementInstance;
  47     class Worker;
  48     class WorkerContext;
  49     class XMLHttpRequest;
  50     class XMLHttpRequestUpload;
  51
  52     typedef int ExceptionCode;
  53
  54     class EventTarget {
  55     public:
  56         virtual MessagePort* toMessagePort();
  57         virtual EventTargetNode* toNode();
  58         virtual XMLHttpRequest* toXMLHttpRequest();
  59         virtual XMLHttpRequestUpload* toXMLHttpRequestUpload();
  60 #if ENABLE(OFFLINE_WEB_APPLICATIONS)
  61         virtual DOMApplicationCache* toDOMApplicationCache();
  62 #endif
  63 #if ENABLE(SVG)
  64         virtual SVGElementInstance* toSVGElementInstance();
  65 #endif
  66 #if ENABLE(WORKERS)
  67         virtual Worker* toWorker();
  68         virtual WorkerContext* toWorkerContext();
  69 #endif
  70
  71         virtual ScriptExecutionContext* scriptExecutionContext() const = 0;
  72
  73         virtual void addEventListener(const AtomicString& eventType, PassRefPtr<EventListener>, bool useCapture) = 0;
  74         virtual void removeEventListener(const AtomicString& eventType, EventListener*, bool useCapture) = 0;
  75         virtual bool dispatchEvent(PassRefPtr<Event>, ExceptionCode&) = 0;
  76
  77         void ref() { refEventTarget(); }
  78         void deref() { derefEventTarget(); }
  79
  80         // Handlers to do/undo actions on the target node before an event is dispatched to it and after the event
  81         // has been dispatched.  The data pointer is handed back by the preDispatch and passed to postDispatch.
  82         virtual void* preDispatchEventHandler(Event*) { return 0; }
  83         virtual void postDispatchEventHandler(Event*, void* /*dataFromPreDispatch*/) { }
  84
  85     protected:
  86         virtual ~EventTarget();
  87
  88     private:
  89         virtual void refEventTarget() = 0;
  90         virtual void derefEventTarget() = 0;
  91     };
  92
  93     void forbidEventDispatch();
  94     void allowEventDispatch();
  95
  96 #ifndef NDEBUG
  97     bool eventDispatchForbidden();
  98 #else
  99     inline void forbidEventDispatch() { }
 100     inline void allowEventDispatch() { }
 101 #endif
 102
 103 }
 104
 105 #endif