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// SocketThreads.h
// Interfaces to the cSocketThreads class representing the heart of MCS's client networking.
// This object takes care of network communication, groups sockets into threads and uses as little threads as possible for full read / write support
// For more detail, see http://forum.mc-server.org/showthread.php?tid=327
/*
Additional details:
When a client is terminating a connection:
- they call the StopReading() method to disable callbacks for the incoming data
- they call the Write() method to queue any outstanding outgoing data
- they call the QueueClose() method to queue the socket to close after outgoing data has been sent.
When a socket slot is marked as having no callback, it is kept alive until its outgoing data queue is empty and its m_ShouldClose flag is set.
This means that the socket can be written to several times before finally closing it via QueueClose()
*/
/// How many clients should one thread handle? (must be less than FD_SETSIZE for your platform)
#define MAX_SLOTS 63
#pragma once
#ifndef CSOCKETTHREADS_H_INCLUDED
#define CSOCKETTHREADS_H_INCLUDED
#include "Socket.h"
#include "IsThread.h"
// Check MAX_SLOTS:
#if MAX_SLOTS >= FD_SETSIZE
#error "MAX_SLOTS must be less than FD_SETSIZE for your platform! (otherwise select() won't work)"
#endif
// fwd:
class cSocket;
class cClientHandle;
class cSocketThreads
{
public:
// Clients of cSocketThreads must implement this interface to be able to communicate
class cCallback
{
public:
/// Called when data is received from the remote party
virtual void DataReceived(const char * a_Data, int a_Size) = 0;
/// Called when data can be sent to remote party; the function is supposed to append outgoing data to a_Data
virtual void GetOutgoingData(AString & a_Data) = 0;
/// Called when the socket has been closed for any reason
virtual void SocketClosed(void) = 0;
} ;
cSocketThreads(void);
~cSocketThreads();
/// Add a (socket, client) pair for processing, data from a_Socket is to be sent to a_Client; returns true if successful
bool AddClient(const cSocket & a_Socket, cCallback * a_Client);
/// Remove the associated socket and the client from processing. The socket is left to send its data and is removed only after all its m_OutgoingData is sent
void RemoveClient(const cCallback * a_Client);
/// Notify the thread responsible for a_Client that the client has something to write
void NotifyWrite(const cCallback * a_Client);
/// Puts a_Data into outgoing data queue for a_Client
void Write(const cCallback * a_Client, const AString & a_Data);
/// Stops reading from the client - when this call returns, no more calls to the callbacks are made
void StopReading(const cCallback * a_Client);
/// Queues the client for closing, as soon as its outgoing data is sent
void QueueClose(const cCallback * a_Client);
private:
class cSocketThread :
public cIsThread
{
typedef cIsThread super;
public:
cSocketThread(cSocketThreads * a_Parent);
~cSocketThread();
// All these methods assume parent's m_CS is locked
bool HasEmptySlot(void) const {return m_NumSlots < MAX_SLOTS; }
bool IsEmpty (void) const {return m_NumSlots == 0; }
void AddClient (const cSocket & a_Socket, cCallback * a_Client); // Takes ownership of the socket
bool RemoveClient(const cCallback * a_Client); // Returns true if removed, false if not found
bool RemoveSocket(const cSocket * a_Socket); // Returns true if removed, false if not found
bool HasClient (const cCallback * a_Client) const;
bool HasSocket (const cSocket * a_Socket) const;
bool NotifyWrite (const cCallback * a_Client); // Returns true if client handled by this thread
bool Write (const cCallback * a_Client, const AString & a_Data); // Returns true if client handled by this thread
bool StopReading (const cCallback * a_Client); // Returns true if client handled by this thread
bool QueueClose (const cCallback * a_Client); // Returns true if client handled by this thread
bool Start(void); // Hide the cIsThread's Start method, we need to provide our own startup to create the control socket
bool IsValid(void) const {return m_ControlSocket2.IsValid(); } // If the Control socket dies, the thread is not valid anymore
private:
cSocketThreads * m_Parent;
// Two ends of the control socket, the first is select()-ed, the second is written to for notifications
cSocket m_ControlSocket1;
cSocket m_ControlSocket2;
// Socket-client-packetqueues triplets.
// Manipulation with these assumes that the parent's m_CS is locked
struct sSlot
{
cSocket m_Socket; // The socket is primarily owned by this
cCallback * m_Client;
AString m_Outgoing; // If sending writes only partial data, the rest is stored here for another send
bool m_ShouldClose; // If true, the socket is to be closed after sending all outgoing data
bool m_ShouldCallClient; // If true, the client callbacks are called. Set to false in StopReading()
} ;
sSlot m_Slots[MAX_SLOTS];
int m_NumSlots; // Number of slots actually used
virtual void Execute(void) override;
void PrepareSet (fd_set * a_Set, cSocket::xSocket & a_Highest); // Puts all sockets into the set, along with m_ControlSocket1
void ReadFromSockets(fd_set * a_Read); // Reads from sockets indicated in a_Read
void WriteToSockets (fd_set * a_Write); // Writes to sockets indicated in a_Write
void RemoveClosedSockets(void); // Removes sockets that have closed from m_Slots[]
} ;
typedef std::list<cSocketThread *> cSocketThreadList;
cCriticalSection m_CS;
cSocketThreadList m_Threads;
} ;
#endif // CSOCKETTHREADS_H_INCLUDED
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