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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 "AtomicStringHash.h"
     31 #include "EventListener.h"
     32 #include "EventNames.h"
     33 #include "EventTarget.h"
     34 #include "MessagePortChannel.h"
     35 #include <wtf/HashMap.h>
     36 #include <wtf/OwnPtr.h>
     37 #include <wtf/PassOwnPtr.h>
     38 #include <wtf/PassRefPtr.h>
     39 #include <wtf/RefPtr.h>
     40 #include <wtf/Vector.h>
     41 
     42 namespace WebCore {
     43 
     44     class AtomicStringImpl;
     45     class Event;
     46     class Frame;
     47     class MessagePort;
     48     class ScriptExecutionContext;
     49     class String;
     50 
     51     // The overwhelmingly common case is sending a single port, so handle that efficiently with an inline buffer of size 1.
     52     typedef Vector<RefPtr<MessagePort>, 1> MessagePortArray;
     53 
     54     class MessagePort : public RefCounted<MessagePort>, public EventTarget {
     55     public:
     56         static PassRefPtr<MessagePort> create(ScriptExecutionContext& scriptExecutionContext) { return adoptRef(new MessagePort(scriptExecutionContext)); }
     57         ~MessagePort();
     58 
     59         void postMessage(PassRefPtr<SerializedScriptValue> message, ExceptionCode&);
     60         void postMessage(PassRefPtr<SerializedScriptValue> message, const MessagePortArray*, ExceptionCode&);
     61         // FIXME: remove this when we update the ObjC bindings (bug #28774).
     62         void postMessage(PassRefPtr<SerializedScriptValue> message, MessagePort*, ExceptionCode&);
     63 
     64         void start();
     65         void close();
     66 
     67         void entangle(PassOwnPtr<MessagePortChannel>);
     68         PassOwnPtr<MessagePortChannel> disentangle(ExceptionCode&);
     69 
     70         // Disentangle an array of ports, returning the entangled channels.
     71         // Per section 8.3.3 of the HTML5 spec, generates an INVALID_STATE_ERR exception if any of the passed ports are null or not entangled.
     72         // Returns 0 if there is an exception, or if the passed-in array is 0/empty.
     73         static PassOwnPtr<MessagePortChannelArray> disentanglePorts(const MessagePortArray*, ExceptionCode&);
     74 
     75         // Entangles an array of channels, returning an array of MessagePorts in matching order.
     76         // Returns 0 if the passed array is 0/empty.
     77         static PassOwnPtr<MessagePortArray> entanglePorts(ScriptExecutionContext&, PassOwnPtr<MessagePortChannelArray>);
     78 
     79         void messageAvailable();
     80         bool started() const { return m_started; }
     81 
     82         void contextDestroyed();
     83 
     84         virtual ScriptExecutionContext* scriptExecutionContext() const;
     85 
     86         virtual MessagePort* toMessagePort() { return this; }
     87 
     88         void dispatchMessages();
     89 
     90         using RefCounted<MessagePort>::ref;
     91         using RefCounted<MessagePort>::deref;
     92 
     93         bool hasPendingActivity();
     94 
     95         void setOnmessage(PassRefPtr<EventListener> listener)
     96         {
     97             setAttributeEventListener(eventNames().messageEvent, listener);
     98             start();
     99         }
    100         EventListener* onmessage() { return getAttributeEventListener(eventNames().messageEvent); }
    101 
    102         // Returns null if there is no entangled port, or if the entangled port is run by a different thread.
    103         // Returns null otherwise.
    104         // NOTE: This is used solely to enable a GC optimization. Some platforms may not be able to determine ownership of the remote port (since it may live cross-process) - those platforms may always return null.
    105         MessagePort* locallyEntangledPort();
    106         // A port starts out its life entangled, and remains entangled until it is closed or is cloned.
    107         bool isEntangled() { return !m_closed && !isCloned(); }
    108         // A port is cloned if its entangled channel has been removed and sent to a new owner via postMessage().
    109         bool isCloned() { return !m_entangledChannel; }
    110 
    111     private:
    112         MessagePort(ScriptExecutionContext&);
    113 
    114         virtual void refEventTarget() { ref(); }
    115         virtual void derefEventTarget() { deref(); }
    116         virtual EventTargetData* eventTargetData();
    117         virtual EventTargetData* ensureEventTargetData();
    118 
    119         OwnPtr<MessagePortChannel> m_entangledChannel;
    120 
    121         bool m_started;
    122         bool m_closed;
    123 
    124         ScriptExecutionContext* m_scriptExecutionContext;
    125         EventTargetData m_eventTargetData;
    126     };
    127 
    128 } // namespace WebCore
    129 
    130 #endif // MessagePort_h
    131