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/* Copyright (C) 2011 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 NETFILETRANSFER_H
#define NETFILETRANSFER_H
#include <map>
class CNetMessage;
class CNetClientSession;
class CNetServerSession;
class INetSession;
// Assume this is sufficiently less than MTU that packets won't get
// fragmented or dropped.
static const size_t DEFAULT_FILE_TRANSFER_PACKET_SIZE = 1024;
// To improve performance without flooding ENet's internal buffers,
// maintain a small number of in-flight packets.
// Pick numbers so that with e.g. 200ms round-trip latency
// we can hopefully get windowSize*packetSize*1000/200 = 160KB/s bandwidth
static const size_t DEFAULT_FILE_TRANSFER_WINDOW_SIZE = 32;
// Some arbitrary limit to make it slightly harder to use up all of someone's RAM
static const size_t MAX_FILE_TRANSFER_SIZE = 8*MiB;
/**
* Asynchronous file-receiving task.
* Other code should subclass this, implement OnComplete(),
* then pass it to CNetFileTransferer::StartTask.
*/
class CNetFileReceiveTask
{
public:
CNetFileReceiveTask() : m_RequestID(0), m_Length(0) { }
virtual ~CNetFileReceiveTask() {}
/**
* Called when m_Buffer contains the full received data.
*/
virtual void OnComplete() = 0;
// TODO: Ought to have an OnFailure, e.g. when the session drops or there's another error
/**
* Uniquely identifies the request within the scope of its CNetFileTransferer.
* Set automatically by StartTask.
*/
u32 m_RequestID;
size_t m_Length;
std::string m_Buffer;
};
/**
* Handles transferring files between clients and servers.
*/
class CNetFileTransferer
{
public:
CNetFileTransferer(INetSession* session)
: m_Session(session), m_NextRequestID(1), m_LastProgressReportTime(0)
{
}
/**
* Should be called when a message is received from the network.
* Returns INFO::SKIPPED if the message is not one that this class handles.
* Returns INFO::OK if the message is handled successfully,
* or ERR::FAIL if handled unsuccessfully.
*/
Status HandleMessageReceive(const CNetMessage* message);
/**
* Registers a file-receiving task.
*/
void StartTask(const shared_ptr<CNetFileReceiveTask>& task);
/**
* Registers data to be sent in response to a request.
* (Callers are expected to have their own mechanism for receiving
* requests and deciding what to respond with.)
*/
void StartResponse(u32 requestID, const std::string& data);
/**
* Call frequently (e.g. once per frame) to trigger any necessary
* packet processing.
*/
void Poll();
private:
/**
* Asynchronous file-sending task.
*/
struct CNetFileSendTask
{
u32 requestID;
std::string buffer;
size_t offset;
size_t maxWindowSize;
size_t packetsInFlight;
};
INetSession* m_Session;
u32 m_NextRequestID;
typedef std::map<u32, shared_ptr<CNetFileReceiveTask> > FileReceiveTasksMap;
FileReceiveTasksMap m_FileReceiveTasks;
typedef std::map<u32, CNetFileSendTask> FileSendTasksMap;
FileSendTasksMap m_FileSendTasks;
double m_LastProgressReportTime;
};
#endif // NETFILETRANSFER_H
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