Connection.h

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//
// Connection.h
//
// Copyright (c) Shareaza Development Team, 2002-2005.
// This file is part of SHAREAZA (www.shareaza.com)
//
// Shareaza 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.
//
// Shareaza 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 Shareaza; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//

// CConnection holds a socket used to communicate with a remote computer, and is the root of a big inheritance tree
// http://wiki.shareaza.com/static/Developers.Code.CConnection

// Make the compiler only include the lines here once, this is the same thing as pragma once
#if !defined(AFX_CONNECTION_H__6312EF26_B2C8_431F_93EF_243EA5E1A3DF__INCLUDED_)
#define AFX_CONNECTION_H__6312EF26_B2C8_431F_93EF_243EA5E1A3DF__INCLUDED_

// Only include the lines beneath this one once
#pragma once

// Tell the compiler these classes exist, and it will find out more about them soon
class CBuffer;
class CConnection;

// Keep track of how fast we are reading or writing bytes to a socket
typedef struct
{
        // Options to limit bandwidth
        DWORD* pLimit;    // Points to a DWORD that holds the limit for this bandwidth meter
        BOOL   bUnscaled; // Set to true to worry about bandwidth even if the program settings don't

        // Transfer statistics
        DWORD nTotal;   // The total number of bytes read or written
        DWORD tLast;    // The time the last read or write happened
        DWORD nMeasure; // The average speed in bytes per second over the last 2 seconds

        // The arrays of byte counts and times
        DWORD pHistory[64]; // 64 records of a number of bytes transferred
        DWORD pTimes[64];   // The times each of these transfers happened
        DWORD nPosition;    // The next spot in the array to use
        DWORD tLastAdd;     // When we last recorded a transfer of some bytesThe last time something was recorded into pHistory and pTimes
        DWORD tLastSlot;    // When we started using this time slot

} TCPBandwidthMeter;

// A socket connection to a remote compueter on the Internet running peer-to-peer software
class CConnection
{

public:

        // Make a new CConnection object, and delete one
        CConnection();
        virtual ~CConnection();

public:

        // The remote computer's IP address, who connected to the other, are we connected, and when it happened
        SOCKADDR_IN m_pHost;      // The remote computer's IP address in Windows Sockets format
        CString     m_sAddress;   // The same IP address in a string like "1.2.3.4"
        BOOL        m_bInitiated; // True if we initiated the connection, false if the remote computer connected to us
        BOOL        m_bConnected; // True when the socket is connected
        DWORD       m_tConnected; // The tick count when the connection was made

public:

        // The actual socket, buffers for reading and writing bytes, and some headers from the other computer
        SOCKET   m_hSocket;     // The actual Windows socket for the Internet connection to the remote computer
        CBuffer* m_pInput;      // Data from the remote computer, will be compressed if the remote computer is sending compressed data
        CBuffer* m_pOutput;     // Data to send to the remote computer, will be compressed if we are sending the remote computer compressed data
        CString  m_sUserAgent;  // The name of the program the remote computer is running
        CString  m_sLastHeader; // The handshake header that ReadHeaders most recently read

public:

        // Structures to control bandwidth in each direction
        TCPBandwidthMeter m_mInput;     // Input and output TCP bandwidth meters
        TCPBandwidthMeter m_mOutput;
        int               m_nQueuedRun; // The queued run state of 0, 1, or 2 (do)

public:

        // Make a connection, accept a connection, copy a connection, and close a connection
        virtual BOOL ConnectTo(SOCKADDR_IN* pHost);                  // Connect to an IP address and port number
        virtual BOOL ConnectTo(IN_ADDR* pAddress, WORD nPort);
        virtual void AcceptFrom(SOCKET hSocket, SOCKADDR_IN* pHost); // Accept a connection from a remote computer
        virtual void AttachTo(CConnection* pConnection);             // Copy a connection (do)
        virtual void Close();                                        // Disconnect from the remote computer

public:

        // Exchange data with the other computer, measure bandwidth, and work with headers
        BOOL DoRun();          // Communicate with the other computer, reading and writing everything we can right now
        void QueueRun();       // (do) may no longer be in use
        void Measure();        // Measure the bandwidth, setting nMeasure in the bandwidth meters for each direction
        BOOL ReadHeaders();    // Read text headers sitting in the input buffer
        BOOL SendMyAddress();  // If we are listening on a port, tell the other computer our IP address and port number
        BOOL IsAgentBlocked(); // Check the other computer's software title against our list of programs not to talk to

protected:

        // Read and write data through the socket, and look at headers
        virtual BOOL OnRun();                // (do) just returns true
        virtual BOOL OnConnected();          // (do) just returns true
        virtual BOOL OnRead();               // Read data waiting in the socket into the input buffer
        virtual BOOL OnWrite();              // Move the contents of the output buffer into the socket
        virtual void OnDropped(BOOL bError); // (do) empty
        virtual BOOL OnHeaderLine(CString& strHeader, CString& strValue); // Processes a single line from the headers
        virtual BOOL OnHeadersComplete();    // (do) just returns true

public:

        // Encode and decode URL text, and see if a string starts with a tag
        static CString URLEncode(LPCTSTR pszInput);                   // Encode "hello world" into "hello%20world"
        static CString URLDecode(LPCTSTR pszInput);                   // Decode "hello%20world" back to "hello world"
        static CString URLDecodeANSI(LPCTSTR pszInput);               // Decodes properly encoded URLs
        static CString URLDecodeUnicode(LPCTSTR pszInput);            // Decodes URLs with extended characters
        static BOOL    StartsWith(LPCTSTR pszInput, LPCTSTR pszText); // StartsWith("hello world", "hello") is true
};

// End the group of lines to only include once, pragma once doesn't require an endif at the bottom
#endif // !defined(AFX_CONNECTION_H__6312EF26_B2C8_431F_93EF_243EA5E1A3DF__INCLUDED_)

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