1/* 2 * Copyright (C) 2009 Google 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 are 6 * met: 7 * 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above 11 * copyright notice, this list of conditions and the following disclaimer 12 * in the documentation and/or other materials provided with the 13 * distribution. 14 * * Neither the name of Google Inc. nor the names of its 15 * contributors may be used to endorse or promote products derived from 16 * this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY 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#ifndef PlatformMessagePortChannel_h 32#define PlatformMessagePortChannel_h 33 34#include "MessagePortChannel.h" 35 36#include <wtf/MessageQueue.h> 37#include <wtf/PassRefPtr.h> 38#include <wtf/Threading.h> 39 40namespace WebCore { 41 42 class MessagePort; 43 44 // PlatformMessagePortChannel is a platform-dependent interface to the remote side of a message channel. 45 // This default implementation supports multiple threads running within a single process. Implementations for multi-process platforms should define these public APIs in their own platform-specific PlatformMessagePortChannel file. 46 // The goal of this implementation is to eliminate contention except when cloning or closing the port, so each side of the channel has its own separate mutex. 47 class PlatformMessagePortChannel : public ThreadSafeRefCounted<PlatformMessagePortChannel> { 48 public: 49 static void createChannel(PassRefPtr<MessagePort>, PassRefPtr<MessagePort>); 50 51 // APIs delegated from MessagePortChannel.h 52 bool entangleIfOpen(MessagePort*); 53 void disentangle(); 54 void postMessageToRemote(PassOwnPtr<MessagePortChannel::EventData>); 55 bool tryGetMessageFromRemote(OwnPtr<MessagePortChannel::EventData>&); 56 void close(); 57 bool isConnectedTo(MessagePort*); 58 bool hasPendingActivity(); 59 MessagePort* locallyEntangledPort(const ScriptExecutionContext*); 60 61 // Wrapper for MessageQueue that allows us to do thread safe sharing by two proxies. 62 class MessagePortQueue : public ThreadSafeRefCounted<MessagePortQueue> { 63 public: 64 static PassRefPtr<MessagePortQueue> create() { return adoptRef(new MessagePortQueue()); } 65 66 PassOwnPtr<MessagePortChannel::EventData> tryGetMessage() 67 { 68 return m_queue.tryGetMessage(); 69 } 70 71 bool appendAndCheckEmpty(PassOwnPtr<MessagePortChannel::EventData> message) 72 { 73 return m_queue.appendAndCheckEmpty(message); 74 } 75 76 bool isEmpty() 77 { 78 return m_queue.isEmpty(); 79 } 80 81 private: 82 MessagePortQueue() { } 83 84 MessageQueue<MessagePortChannel::EventData> m_queue; 85 }; 86 87 ~PlatformMessagePortChannel(); 88 89 private: 90 static PassRefPtr<PlatformMessagePortChannel> create(PassRefPtr<MessagePortQueue> incoming, PassRefPtr<MessagePortQueue> outgoing); 91 PlatformMessagePortChannel(PassRefPtr<MessagePortQueue> incoming, PassRefPtr<MessagePortQueue> outgoing); 92 93 PassRefPtr<PlatformMessagePortChannel> entangledChannel(); 94 void setEntangledChannel(PassRefPtr<PlatformMessagePortChannel>); 95 96 void setRemotePort(MessagePort*); 97 MessagePort* remotePort(); 98 void closeInternal(); 99 100 // Mutex used to ensure exclusive access to the object internals. 101 Mutex m_mutex; 102 103 // Pointer to our entangled pair - cleared when close() is called. 104 RefPtr<PlatformMessagePortChannel> m_entangledChannel; 105 106 // Reference to the message queue for the (local) entangled port. 107 RefPtr<MessagePortQueue> m_incomingQueue; 108 RefPtr<MessagePortQueue> m_outgoingQueue; 109 110 // The port we are connected to (the remote port) - this is the port that is notified when new messages arrive. 111 MessagePort* m_remotePort; 112 }; 113 114} // namespace WebCore 115 116#endif // PlatformMessagePortChannel_h 117