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      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 MessagePort_h
     28 #define MessagePort_h
     29 
     30 #include "bindings/v8/ScriptWrappable.h"
     31 #include "core/dom/EventListener.h"
     32 #include "core/dom/EventTarget.h"
     33 #include "core/dom/MessagePortChannel.h"
     34 #include "wtf/Forward.h"
     35 #include "wtf/OwnPtr.h"
     36 #include "wtf/PassOwnPtr.h"
     37 #include "wtf/PassRefPtr.h"
     38 #include "wtf/RefPtr.h"
     39 #include "wtf/Vector.h"
     40 
     41 namespace WebCore {
     42 
     43 class Event;
     44 class ExceptionState;
     45 class Frame;
     46 class MessagePort;
     47 class ScriptExecutionContext;
     48 
     49 // The overwhelmingly common case is sending a single port, so handle that efficiently with an inline buffer of size 1.
     50 typedef Vector<RefPtr<MessagePort>, 1> MessagePortArray;
     51 
     52 class MessagePort : public RefCounted<MessagePort>, public ScriptWrappable, public EventTarget {
     53 public:
     54     static PassRefPtr<MessagePort> create(ScriptExecutionContext& scriptExecutionContext) { return adoptRef(new MessagePort(scriptExecutionContext)); }
     55     virtual ~MessagePort();
     56 
     57     void postMessage(PassRefPtr<SerializedScriptValue> message, const MessagePortArray*, ExceptionState&);
     58 
     59     void start();
     60     void close();
     61 
     62     void entangle(PassOwnPtr<MessagePortChannel>);
     63     PassOwnPtr<MessagePortChannel> disentangle();
     64 
     65     // Returns 0 if there is an exception, or if the passed-in array is 0/empty.
     66     static PassOwnPtr<MessagePortChannelArray> disentanglePorts(const MessagePortArray*, ExceptionState&);
     67 
     68     // Returns 0 if the passed array is 0/empty.
     69     static PassOwnPtr<MessagePortArray> entanglePorts(ScriptExecutionContext&, PassOwnPtr<MessagePortChannelArray>);
     70 
     71     void messageAvailable();
     72     bool started() const { return m_started; }
     73 
     74     void contextDestroyed();
     75 
     76     virtual const AtomicString& interfaceName() const OVERRIDE;
     77     virtual ScriptExecutionContext* scriptExecutionContext() const OVERRIDE;
     78 
     79     void dispatchMessages();
     80 
     81     using RefCounted<MessagePort>::ref;
     82     using RefCounted<MessagePort>::deref;
     83 
     84     bool hasPendingActivity();
     85 
     86     void setOnmessage(PassRefPtr<EventListener> listener, DOMWrapperWorld* world)
     87     {
     88         setAttributeEventListener(eventNames().messageEvent, listener, world);
     89         start();
     90     }
     91     EventListener* onmessage(DOMWrapperWorld* world) { return getAttributeEventListener(eventNames().messageEvent, world); }
     92 
     93     // Returns null if there is no entangled port, or if the entangled port is run by a different thread.
     94     // This is used solely to enable a GC optimization. Some platforms may not be able to determine ownership
     95     // of the remote port (since it may live cross-process) - those platforms may always return null.
     96     MessagePort* locallyEntangledPort();
     97 
     98     // A port starts out its life entangled, and remains entangled until it is closed or is cloned.
     99     bool isEntangled() { return !m_closed && !isNeutered(); }
    100 
    101     // A port gets neutered when it is transferred to a new owner via postMessage().
    102     bool isNeutered() { return !m_entangledChannel; }
    103 
    104 private:
    105     explicit MessagePort(ScriptExecutionContext&);
    106 
    107     virtual void refEventTarget() OVERRIDE { ref(); }
    108     virtual void derefEventTarget() OVERRIDE { deref(); }
    109     virtual EventTargetData* eventTargetData() OVERRIDE;
    110     virtual EventTargetData* ensureEventTargetData() OVERRIDE;
    111 
    112     OwnPtr<MessagePortChannel> m_entangledChannel;
    113 
    114     bool m_started;
    115     bool m_closed;
    116 
    117     ScriptExecutionContext* m_scriptExecutionContext;
    118     EventTargetData m_eventTargetData;
    119 };
    120 
    121 } // namespace WebCore
    122 
    123 #endif // MessagePort_h
    124