source: protocols/ft.h @ 0cab388

/********************************************************************\
* BitlBee -- An IRC to other IM-networks gateway                     *
*                                                                    *
* Copyright 2006 Marijn Kruisselbrink and others                     *
\********************************************************************/

/* Generic file transfer header                                     */

/*
  This program 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.

  This program 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 with
  the Debian GNU/Linux distribution in /usr/share/common-licenses/GPL;
  if not, write to the Free Software Foundation, Inc., 59 Temple Place,
  Suite 330, Boston, MA  02111-1307  USA
*/

#ifndef _FT_H
#define _FT_H

/*
 * One buffer is needed for each transfer. The receiver stores a message
 * in it and gives it to the sender. The sender will stall the receiver
 * till the buffer has been sent out.
 */
#define FT_BUFFER_SIZE 2048

typedef enum {
        FT_STATUS_LISTENING     = 1,
        FT_STATUS_TRANSFERRING  = 2,
        FT_STATUS_FINISHED      = 4,
        FT_STATUS_CANCELED      = 8,
        FT_STATUS_CONNECTING    = 16
} file_status_t;

/*
 * This structure holds all irc specific information regarding an incoming (from the point of view of
 * the irc client) file transfer. New instances of this struct should only be created by calling the
 * imcb_file_send_start() method, which will initialize most of the fields. The data field and the various
 * methods are zero-initialized. Instances will automatically be deleted once the transfer is completed,
 * canceled, or the connection to the irc client has been lost (note that also if only the irc connection
 * and not the file transfer connection is lost, the file transfer will still be canceled and freed).
 *
 * The following (poor ascii-art) diagram illustrates what methods are called for which status-changes:
 *
 *                              /-----------\                    /----------\
 *                     -------> | LISTENING | -----------------> | CANCELED |
 *                              \-----------/  [canceled,]free   \----------/
 *                                    |
 *                                    | accept
 *                                    V
 *                     /------ /-------------\                    /------------------------\
 *         out_of_data |       | TRANSFERING | -----------------> | TRANSFERING | CANCELED |
 *                     \-----> \-------------/  [canceled,]free   \------------------------/
 *                                    |
 *                                    | finished,free
 *                                    V
 *                       /------------------------\
 *                       | TRANSFERING | FINISHED |
 *                       \------------------------/
 */
typedef struct file_transfer {

        /* Are we sending something? */
        int sending;

        /*
         * The current status of this file transfer.
         */ 
        file_status_t status;
        
        /*
         * file size
         */
        size_t file_size;
        
        /*
         * Number of bytes that have been successfully transferred.
         */
        size_t bytes_transferred;

        /*
         * Time started. Used to calculate kb/s.
         */
        time_t started;

        /*
         * file name
         */
        char *file_name;

        /*
         * A unique local ID for this file transfer.
         */
        unsigned int local_id;

        /*
         * IM-protocol specific data associated with this file transfer.
         */
        gpointer data;
        
        /*
         * Private data.
         */
        gpointer priv;
        
        /*
         * If set, called after succesful connection setup.
         */
        void (*accept) ( struct file_transfer *file );
        
        /*
         * If set, called when the transfer is canceled or finished.
         * Subsequently, this structure will be freed.
         *
         */
        void (*free) ( struct file_transfer *file );
        
        /*
         * If set, called when the transfer is finished and successful.
         */
        void (*finished) ( struct file_transfer *file );
        
        /*
         * If set, called when the transfer is canceled.
         * ( canceled either by the transfer implementation or by
         *  a call to imcb_file_canceled )
         */
        void (*canceled) ( struct file_transfer *file, char *reason );
        
        /*
         * called by the sending side to indicate that it is writable.
         * The callee should check if data is available and call the 
         * function(as seen below) if that is the case.
         */
        gboolean (*write_request) ( struct file_transfer *file );

        /*
         * When sending files, protocols register this function to receive data.
         * This should only be called once after write_request is called. The caller
         * should not read more data until write_request is called again. This technique
         * avoids buffering.
         */
        gboolean (*write) (struct file_transfer *file, char *buffer, unsigned int len );

        /* The send buffer associated with this transfer.
         * Since receivers always wait for a write_request call one is enough.
         */
        char buffer[FT_BUFFER_SIZE];

} file_transfer_t;

/*
 * This starts a file transfer from bitlbee to the user.
 */
file_transfer_t *imcb_file_send_start( struct im_connection *ic, char *user_nick, char *file_name, size_t file_size );

/*
 * This should be called by a protocol when the transfer is canceled. Note that
 * the canceled() and free() callbacks given in file will be called by this function.
 */
void imcb_file_canceled( file_transfer_t *file, char *reason );

gboolean imcb_file_recv_start( file_transfer_t *ft );
#endif