1 files changed, 169 insertions, 0 deletions

diff --git a/src/OSSupport/SocketThreads.h b/src/OSSupport/SocketThreads.h
new file mode 100644
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+++ b/src/OSSupport/SocketThreads.h
@@ -0,0 +1,169 @@
+
+// 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
+	} ;
+	
+	typedef std::list<cSocketThread *> cSocketThreadList;
+	
+	
+	cCriticalSection  m_CS;
+	cSocketThreadList m_Threads;
+} ;
+
+
+
+
+
+#endif  // CSOCKETTHREADS_H_INCLUDED
+
+
+
+