gecko/ipc/glue/RPCChannel.h

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: sw=4 ts=4 et :
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * 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
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * 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.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#ifndef ipc_glue_RPCChannel_h
#define ipc_glue_RPCChannel_h 1

// FIXME/cjones probably shouldn't depend on this
#include <stack>

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

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

namespace mozilla {
namespace ipc {
//-----------------------------------------------------------------------------

class RPCChannel : public IPC::Channel::Listener
{
private:
    typedef mozilla::CondVar CondVar;
    typedef mozilla::Mutex Mutex;

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

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

    class Listener
    {
    public:
        enum Result {
            // We processed the message, and it can be forgotten
            MsgProcessed,
            // We haven't heard of this message type
            MsgNotKnown,
            // We weren't in a state to receive this message
            MsgNotAllowed
        };

        virtual ~Listener() { }
        virtual Result OnCallReceived(const Message& aMessage,
                                      Message** aReply) = 0;
    };

    /**
     * Convert the asynchronous channel |aChannel| into a channel with
     * RPC semantics.  Received messages are passed down to
     * |aListener|.
     *
     * FIXME do away with |aMode|
     */
    RPCChannel(Listener* aListener) :
        mTransport(0),
        mListener(aListener),
        mChannelState(ChannelClosed),
        mMutex("mozilla.ipc.RPCChannel.mMutex"),
        mCvar(mMutex, "mozilla.ipc.RPCChannel.mCvar")
    {
    }

    virtual ~RPCChannel()
    {
        if (mTransport)
            Close();
        mTransport = 0;
    }

    // Open  from the perspective of the RPC layer; the transport
    // should already be connected, or ready to connect.
    bool Open(Transport* aTransport, MessageLoop* aIOLoop=0);
    
    // Close from the perspective of the RPC layer; leaves the
    // underlying transport channel open, however.
    void Close();

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

    // Make an RPC to the other side of the channel
    virtual bool Call(Message* msg, Message* reply);

private:
    // Task created when we're idle (wrt this channel), and the other 
    // side has made an RPC to us
    void OnIncomingCall(Message msg);
    // Process an RPC made from the other side to here
    bool ProcessIncomingCall(Message msg);

    void OnChannelOpened();
    void SendCall(Message* aCall);
    void SendReply(Message* aReply);

    Transport* mTransport;
    Listener* mListener;
    ChannelState mChannelState;
    MessageLoop* mIOLoop;       // thread where IO happens
    MessageLoop* mWorkerLoop;   // thread where work is done
    Mutex mMutex;
    CondVar mCvar;
    std::stack<Message> mPending;
};


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