NetMessage.h

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/* Copyright (C) 2017 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef NETMESSAGE_H
#define NETMESSAGE_H
 
#include "Serialization.h"
 
// We need the enum from NetMessages.h, but we can't create any classes in
// NetMessages.h, since they in turn require CNetMessage to be defined
#define ALLNETMSGS_DONT_CREATE_NMTS
#include "NetMessages.h"
#undef ALLNETMSGS_DONT_CREATE_NMTS
 
/**
 * The base class for all network messages exchanged within the game.
 */
class CNetMessage : public ISerializable
{
    friend class CNetSession;
 
public:
 
    CNetMessage();
    CNetMessage(NetMessageType type);
    virtual ~CNetMessage();
 
    /**
     * Retrieves the message type.
     * @return                      Message type
     */
    NetMessageType GetType() const { return m_Type; }
 
    /**
     * Serialize the message into the specified buffer parameter. The size
     * required by the buffer parameter can be found by a call to
     * GetSerializedLength method. The information contained within the message
     * must be serialized before the message is sent. By default only the
     * message type and its size are serialized in the buffer parameter.
     *
     * @param pBuffer               Buffer where to serialize the message
     * @return                      The position in the buffer right after the
     *                              serialized message
     */
    virtual u8* Serialize(u8* pBuffer) const;
 
    /**
     * Deserializes the message from the specified buffer.
     *
     * @param pStart                Message start within the serialized buffer
     * @param pEnd                  Message end within the serialized buffer
     * @return                      The position in the buffer right after the
     *                              message or NULL if an error occurred
     */
    virtual const u8* Deserialize(const u8* pStart, const u8* pEnd);
 
    /**
     * Retrieves the size in bytes of the serialized message. Before calling
     * Serialize, the memory size for the buffer where to serialize the message
     * object can be found by calling this method.
     *
     * @return                          The size of serialized message
     */
    virtual size_t GetSerializedLength() const;
 
    /**
     * Returns a string representation for the message
     *
     * @return                          The message as a string
     */
    virtual CStr ToString() const;
 
private:
    NetMessageType  m_Type;             // Message type
};
 
/**
 * Creates messages from data received through the network.
 */
class CNetMessageFactory
{
public:
 
    /**
     * Factory method which creates a message object based on the given data
     *
     * @param pData                     Data buffer
     * @param dataSize                  Size of data buffer
     * @param scriptInterface           Script instance to use when constructing scripted messages
     * @return                          The new message created
     */
    static CNetMessage* CreateMessage(const void* pData, size_t dataSize, const ScriptInterface& scriptInterface);
};
 
/**
 * Special message type for simulation commands.
 * These commands are exposed as arbitrary JS objects, associated with a specific player.
 */
class CSimulationMessage : public CNetMessage
{
public:
    CSimulationMessage(const ScriptInterface& scriptInterface);
    CSimulationMessage(const ScriptInterface& scriptInterface, u32 client, i32 player, u32 turn, JS::HandleValue data);
 
    /** The compiler can't create a copy constructor because of the PersistentRooted member,
     * so we have to write it manually.
     * NOTE: It doesn't clone the m_Data member and the copy will reference the same JS::Value!
     */
    CSimulationMessage(const CSimulationMessage& orig);
 
    virtual u8* Serialize(u8* pBuffer) const;
    virtual const u8* Deserialize(const u8* pStart, const u8* pEnd);
    virtual size_t GetSerializedLength() const;
    virtual CStr ToString() const;
 
    u32 m_Client;
    i32 m_Player;
    u32 m_Turn;
    JS::PersistentRooted<JS::Value> m_Data;
private:
    const ScriptInterface& m_ScriptInterface;
};
 
/**
 * Special message type for updated to game startup settings.
 */
class CGameSetupMessage : public CNetMessage
{
    NONCOPYABLE(CGameSetupMessage);
public:
    CGameSetupMessage(const ScriptInterface& scriptInterface);
    CGameSetupMessage(const ScriptInterface& scriptInterface, JS::HandleValue data);
    virtual u8* Serialize(u8* pBuffer) const;
    virtual const u8* Deserialize(const u8* pStart, const u8* pEnd);
    virtual size_t GetSerializedLength() const;
    virtual CStr ToString() const;
 
    JS::PersistentRootedValue m_Data;
private:
    const ScriptInterface& m_ScriptInterface;
};
 
// This time, the classes are created
#include "NetMessages.h"
 
#endif // NETMESSAGE_H