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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 "EventListener.h"
31 #include "EventTarget.h"
32 #include "MessagePortChannel.h"
33 #include <wtf/Forward.h>
34 #include <wtf/OwnPtr.h>
35 #include <wtf/PassOwnPtr.h>
36 #include <wtf/PassRefPtr.h>
37 #include <wtf/RefPtr.h>
38 #include <wtf/Vector.h>
39 #include <wtf/text/AtomicStringHash.h>
40 
41 namespace WebCore {
42 
43     class Event;
44     class Frame;
45     class MessagePort;
46     class ScriptExecutionContext;
47 
48     // The overwhelmingly common case is sending a single port, so handle that efficiently with an inline buffer of size 1.
49     typedef Vector<RefPtr<MessagePort>, 1> MessagePortArray;
50 
51     class MessagePort : public RefCounted<MessagePort>, public EventTarget {
52     public:
create(ScriptExecutionContext & scriptExecutionContext)53         static PassRefPtr<MessagePort> create(ScriptExecutionContext& scriptExecutionContext) { return adoptRef(new MessagePort(scriptExecutionContext)); }
54         ~MessagePort();
55 
56         void postMessage(PassRefPtr<SerializedScriptValue> message, ExceptionCode&);
57         void postMessage(PassRefPtr<SerializedScriptValue> message, const MessagePortArray*, ExceptionCode&);
58         // FIXME: remove this when we update the ObjC bindings (bug #28774).
59         void postMessage(PassRefPtr<SerializedScriptValue> message, MessagePort*, ExceptionCode&);
60 
61         void start();
62         void close();
63 
64         void entangle(PassOwnPtr<MessagePortChannel>);
65         PassOwnPtr<MessagePortChannel> disentangle(ExceptionCode&);
66 
67         // Disentangle an array of ports, returning the entangled channels.
68         // 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.
69         // Returns 0 if there is an exception, or if the passed-in array is 0/empty.
70         static PassOwnPtr<MessagePortChannelArray> disentanglePorts(const MessagePortArray*, ExceptionCode&);
71 
72         // Entangles an array of channels, returning an array of MessagePorts in matching order.
73         // Returns 0 if the passed array is 0/empty.
74         static PassOwnPtr<MessagePortArray> entanglePorts(ScriptExecutionContext&, PassOwnPtr<MessagePortChannelArray>);
75 
76         void messageAvailable();
started()77         bool started() const { return m_started; }
78 
79         void contextDestroyed();
80 
81         virtual ScriptExecutionContext* scriptExecutionContext() const;
82 
toMessagePort()83         virtual MessagePort* toMessagePort() { return this; }
84 
85         void dispatchMessages();
86 
87         using RefCounted<MessagePort>::ref;
88         using RefCounted<MessagePort>::deref;
89 
90         bool hasPendingActivity();
91 
setOnmessage(PassRefPtr<EventListener> listener)92         void setOnmessage(PassRefPtr<EventListener> listener)
93         {
94             setAttributeEventListener(eventNames().messageEvent, listener);
95             start();
96         }
onmessage()97         EventListener* onmessage() { return getAttributeEventListener(eventNames().messageEvent); }
98 
99         // Returns null if there is no entangled port, or if the entangled port is run by a different thread.
100         // Returns null otherwise.
101         // 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.
102         MessagePort* locallyEntangledPort();
103         // A port starts out its life entangled, and remains entangled until it is closed or is cloned.
isEntangled()104         bool isEntangled() { return !m_closed && !isCloned(); }
105         // A port is cloned if its entangled channel has been removed and sent to a new owner via postMessage().
isCloned()106         bool isCloned() { return !m_entangledChannel; }
107 
108     private:
109         MessagePort(ScriptExecutionContext&);
110 
refEventTarget()111         virtual void refEventTarget() { ref(); }
derefEventTarget()112         virtual void derefEventTarget() { deref(); }
113         virtual EventTargetData* eventTargetData();
114         virtual EventTargetData* ensureEventTargetData();
115 
116         OwnPtr<MessagePortChannel> m_entangledChannel;
117 
118         bool m_started;
119         bool m_closed;
120 
121         ScriptExecutionContext* m_scriptExecutionContext;
122         EventTargetData m_eventTargetData;
123     };
124 
125 } // namespace WebCore
126 
127 #endif // MessagePort_h
128