gecko/ipc/glue/AsyncChannel.h

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
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 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Plugin App.
 *
 * The Initial Developer of the Original Code is
 *   Chris Jones <jones.chris.g@gmail.com>
 * Portions created by the Initial Developer are Copyright (C) 2009
 * the Initial Developer. All Rights Reserved.
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 *
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#ifndef ipc_glue_AsyncChannel_h
#define ipc_glue_AsyncChannel_h 1

#include "base/basictypes.h"
#include "base/message_loop.h"
#include "chrome/common/ipc_channel.h"

#include "mozilla/CondVar.h"
#include "mozilla/Mutex.h"


//-----------------------------------------------------------------------------

namespace mozilla {
namespace ipc {

struct HasResultCodes
{
    enum Result {
        MsgProcessed,
        MsgNotKnown,
        MsgNotAllowed,
        MsgPayloadError,
        MsgRouteError,
        MsgValueError,
    };
};

class AsyncChannel : public IPC::Channel::Listener, protected HasResultCodes
{
protected:
    typedef mozilla::CondVar CondVar;
    typedef mozilla::Mutex Mutex;

    enum ChannelState {
        ChannelClosed,
        ChannelOpening,
        ChannelConnected,
        ChannelError
    };

public:
    typedef IPC::Channel Transport;
    typedef IPC::Message Message;

    class /*NS_INTERFACE_CLASS*/ AsyncListener: protected HasResultCodes
    {
    public:
        virtual ~AsyncListener() { }
        virtual Result OnMessageReceived(const Message& aMessage) = 0;
    };

public:
    AsyncChannel(AsyncListener* aListener) :
        mTransport(0),
        mListener(aListener),
        mChannelState(ChannelClosed),
        mMutex("mozilla.ipc.AsyncChannel.mMutex"),
        mCvar(mMutex, "mozilla.ipc.AsyncChannel.mCvar"),
        mIOLoop(),
        mWorkerLoop()
    {
    }

    virtual ~AsyncChannel()
    {
        if (!mChild && mTransport)
            Close();
        // we only hold a weak ref to the transport, which is "owned"
        // by GeckoChildProcess/GeckoThread
        mTransport = 0;
    }

    // Open  from the perspective of the transport layer; the underlying
    // socketpair/pipe should already be created.
    //
    // Returns true iff the transport layer was successfully connected,
    // i.e., mChannelState == ChannelConnected.
    bool Open(Transport* aTransport, MessageLoop* aIOLoop=0);
    
    // Close the underlying transport channel.
    void Close();

    // Asynchronously send a message to the other side of the channel
    bool Send(Message* msg);

    // Implement the IPC::Channel::Listener interface
    NS_OVERRIDE virtual void OnMessageReceived(const Message& msg);
    NS_OVERRIDE virtual void OnChannelConnected(int32 peer_pid);
    NS_OVERRIDE virtual void OnChannelError();

protected:
    // Can be run on either thread
    void AssertWorkerThread()
    {
        NS_ABORT_IF_FALSE(mWorkerLoop == MessageLoop::current(),
                          "not on worker thread!");
    }

    void AssertIOThread()
    {
        NS_ABORT_IF_FALSE(mIOLoop == MessageLoop::current(),
                          "not on IO thread!");
    }

    bool Connected() {
        mMutex.AssertCurrentThreadOwns();
        return ChannelConnected == mChannelState;
    }

    // Run on the worker thread
    void OnDispatchMessage(const Message& aMsg);
    bool MaybeHandleError(Result code, const char* channelName);
    void ReportConnectionError(const char* channelName);

    void PrintErrorMessage(const char* channelName, const char* msg)
    {
        fprintf(stderr, "\n###!!! [%s][%s] Error: %s\n\n",
                mChild ? "Child" : "Parent", channelName, msg);
    }

    // Run on the IO thread
    void OnChannelOpened();
    void OnSend(Message* aMsg);
    void OnClose();

    Transport* mTransport;
    AsyncListener* mListener;
    ChannelState mChannelState;
    Mutex mMutex;
    CondVar mCvar;
    MessageLoop* mIOLoop;       // thread where IO happens
    MessageLoop* mWorkerLoop;   // thread where work is done
    bool mChild;                // am I the child or parent?
};


} // namespace ipc
} // namespace mozilla
#endif  // ifndef ipc_glue_AsyncChannel_h