vdr-plugin-streamdev/server/connection.h

/*
 *  $Id: connection.h,v 1.6 2008/10/14 11:05:47 schmirl Exp $
 */
 
#ifndef VDR_STREAMDEV_SERVER_CONNECTION_H
#define VDR_STREAMDEV_SERVER_CONNECTION_H

#include "tools/socket.h"
#include "common.h"

class cChannel;
class cDevice;

/* Basic capabilities of a straight text-based protocol, most functions
   virtual to support more complicated protocols */

class cServerConnection: public cListObject, public cTBSocket 
{
private:
	const char *m_Protocol;
	bool        m_DeferClose;
	bool        m_Pending;

	char        m_ReadBuffer[MAXPARSEBUFFER];
	uint        m_ReadBytes;
	
	char        m_WriteBuffer[MAXPARSEBUFFER];
	uint        m_WriteBytes;
	uint        m_WriteIndex;

protected:
	/* Will be called when a command terminated by a newline has been 
	   received */
	virtual bool Command(char *Cmd) = 0;

	/* Will put Message into the response queue, which will be sent in the next
	   server cycle. Note that Message will be line-terminated by Respond. 
	   Only one line at a time may be sent. If there are lines to follow, set
	   Last to false. Command(NULL) will be called in the next cycle, so you can
	   post the next line. */
	virtual bool Respond(const char *Message, bool Last = true, ...);
			//__attribute__ ((format (printf, 2, 4)));

public:
	/* If you derive, specify a short string such as HTTP for Protocol, which
	   will be displayed in error messages */
	cServerConnection(const char *Protocol);
	virtual ~cServerConnection();

	/* If true, any client IP will be accepted */
	virtual bool CanAuthenticate(void) { return false; }

	/* Gets called if the client has been accepted by the core */
	virtual void Welcome(void) { }
	
	/* Gets called if the client has been rejected by the core */
	virtual void Reject(void) { DeferClose(); }

	/* Get the client socket's file number */
	virtual int Socket(void) const { return (int)*this; }

	/* Determine if there is data to send or any command pending */
	virtual bool HasData(void) const;

	/* Gets called by server when the socket can accept more data. Writes
	   the buffer filled up by Respond(). Calls Command(NULL) if there is a
	   command pending. Returns false in case of an error */
	virtual bool Write(void);

	/* Gets called by server when there is incoming data to read. Calls
	   Command() for each line. Returns false in case of an error, or if
	   the connection shall be closed and removed by the server */
	virtual bool Read(void);

	/* Is polled regularely by the server. Returns true if the connection
	   needs to be terminated. */
	virtual bool Abort(void) const = 0;

	/* Will make the socket close after sending all queued output data */
	void DeferClose(void) { m_DeferClose = true; }

	/* Will retrieve an unused device for transmitting data. Use the returned
	   cDevice in a following call to StartTransfer */
	cDevice *GetDevice(const cChannel *Channel, int Priority);

	virtual void Flushed(void) {}

	virtual void Detach(void) = 0;
	virtual void Attach(void) = 0;
};

inline bool cServerConnection::HasData(void) const
{
	return m_WriteBytes > 0 || m_Pending || m_DeferClose;
}

#endif // VDR_STREAMDEV_SERVER_CONNECTION_H