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/********************************************************************\
* 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;
	struct im_connection *ic;
	
	/*
	 * 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( struct im_connection *ic, file_transfer_t *file, char *reason );

gboolean imcb_file_recv_start( struct im_connection *ic, file_transfer_t *ft );

void imcb_file_finished( struct im_connection *ic, file_transfer_t *file );
#endif
>ic = purple_ic_by_pa( xfer->account ); purple_xfer_set_local_filename( xfer, px->fn ); /* Sadly the xfer struct is still empty ATM so come back after the caller is done. */ b_timeout_add( 0, prplcb_xfer_new_send_cb, xfer ); } else { struct file_transfer *ft = next_ft; struct prpl_xfer_data *px = ft->data; xfer->ui_data = px; px->xfer = xfer; next_ft = NULL; } } static gboolean prplcb_xfer_new_send_cb( gpointer data, gint fd, b_input_condition cond ) { PurpleXfer *xfer = data; struct im_connection *ic = purple_ic_by_pa( xfer->account ); struct prpl_xfer_data *px = xfer->ui_data; PurpleBuddy *buddy; const char *who; buddy = purple_find_buddy( xfer->account, xfer->who ); who = buddy ? purple_buddy_get_name( buddy ) : xfer->who; /* TODO(wilmer): After spreading some more const goodness in BitlBee, remove the evil cast below. */ px->ft = imcb_file_send_start( ic, (char*) who, xfer->filename, xfer->size ); px->ft->data = px; px->ft->accept = prpl_xfer_accept; px->ft->canceled = prpl_xfer_canceled; px->ft->write_request = prpl_xfer_write_request; return FALSE; } gboolean try_write_to_ui( gpointer data, gint fd, b_input_condition cond ) { struct file_transfer *ft = data; struct prpl_xfer_data *px = ft->data; struct stat fs; off_t tx_bytes; /* If we don't have the file opened yet, there's no data so wait. */ if( px->fd < 0 || !px->ui_wants_data ) return FALSE; tx_bytes = lseek( px->fd, 0, SEEK_CUR ); fstat( px->fd, &fs ); if( fs.st_size > tx_bytes ) { char buf[1024]; size_t n = MIN( fs.st_size - tx_bytes, sizeof( buf ) ); if( read( px->fd, buf, n ) == n && ft->write( ft, buf, n ) ) { px->ui_wants_data = FALSE; } else { purple_xfer_cancel_local( px->xfer ); imcb_file_canceled( px->ic, ft, "Read error" ); } } if( lseek( px->fd, 0, SEEK_CUR ) == px->xfer->size ) { /*purple_xfer_end( px->xfer );*/ imcb_file_finished( px->ic, ft ); } return FALSE; } /* UI calls this when its buffer is empty and wants more data to send to the user. */ static gboolean prpl_xfer_write_request( struct file_transfer *ft ) { struct prpl_xfer_data *px = ft->data; px->ui_wants_data = TRUE; try_write_to_ui( ft, 0, 0 ); return FALSE; } /* Generic (IM<>UI): */ static void prplcb_xfer_destroy( PurpleXfer *xfer ) { struct prpl_xfer_data *px = xfer->ui_data; g_free( px->fn ); g_free( px->handle ); if( px->fd >= 0 ) close( px->fd ); g_free( px ); } static void prplcb_xfer_progress( PurpleXfer *xfer, double percent ) { struct prpl_xfer_data *px = xfer->ui_data; if( px == NULL ) return; if( purple_xfer_get_type( xfer ) == PURPLE_XFER_SEND ) { if( *px->fn ) { char *slash; unlink( px->fn ); if( ( slash = strrchr( px->fn, '/' ) ) ) { *slash = '\0'; rmdir( px->fn ); } *px->fn = '\0'; } return; } if( px->fd == -1 && percent > 0 ) { /* Weeeeeeeee, we're getting data! That means the file exists by now so open it and start sending to the UI. */ px->fd = open( px->fn, O_RDONLY ); /* Unlink it now, because we don't need it after this. */ unlink( px->fn ); } if( percent < 1 ) try_write_to_ui( px->ft, 0, 0 ); else /* Another nice problem: If we have the whole file, it only gets closed when we return. Problem: There may still be stuff buffered and not written, we'll only see it after the caller close()s the file. So poll the file after that. */ b_timeout_add( 0, try_write_to_ui, px->ft ); } static void prplcb_xfer_cancel_remote( PurpleXfer *xfer ) { struct prpl_xfer_data *px = xfer->ui_data; if( px->ft ) imcb_file_canceled( px->ic, px->ft, "Canceled by remote end" ); else /* px->ft == NULL for sends, because of the two stages. :-/ */ imcb_error( px->ic, "File transfer cancelled by remote end" ); } static void prplcb_xfer_dbg( PurpleXfer *xfer ) { fprintf( stderr, "prplcb_xfer_dbg 0x%p\n", xfer ); } /* Sending files (UI->IM): */ static gboolean prpl_xfer_write( struct file_transfer *ft, char *buffer, unsigned int len ); static gboolean purple_transfer_request_cb( gpointer data, gint fd, b_input_condition cond ); void purple_transfer_request( struct im_connection *ic, file_transfer_t *ft, char *handle ) { struct prpl_xfer_data *px = g_new0( struct prpl_xfer_data, 1 ); char *dir, *basename; ft->data = px; px->ft = ft; dir = g_strdup( "/tmp/bitlbee-purple-ft.XXXXXX" ); if( !mkdtemp( dir ) ) { imcb_error( ic, "Could not create temporary file for file transfer" ); g_free( px ); g_free( dir ); return; } if( ( basename = strrchr( ft->file_name, '/' ) ) ) basename++; else basename = ft->file_name; px->fn = g_strdup_printf( "%s/%s", dir, basename ); px->fd = open( px->fn, O_WRONLY | O_CREAT, 0600 ); g_free( dir ); if( px->fd < 0 ) { imcb_error( ic, "Could not create temporary file for file transfer" ); g_free( px ); g_free( px->fn ); return; } px->ic = ic; px->handle = g_strdup( handle ); imcb_log( ic, "Due to libpurple limitations, the file has to be cached locally before proceeding with the actual file transfer. Please wait..." ); b_timeout_add( 0, purple_transfer_request_cb, ft ); } static void purple_transfer_forward( struct file_transfer *ft ) { struct prpl_xfer_data *px = ft->data; PurpleAccount *pa = px->ic->proto_data; /* xfer_new() will pick up this variable. It's a hack but we're not multi-threaded anyway. */ next_ft = ft; serv_send_file( purple_account_get_connection( pa ), px->handle, px->fn ); } static gboolean purple_transfer_request_cb( gpointer data, gint fd, b_input_condition cond ) { file_transfer_t *ft = data; struct prpl_xfer_data *px = ft->data; if( ft->write == NULL ) { ft->write = prpl_xfer_write; imcb_file_recv_start( px->ic, ft ); } ft->write_request( ft ); return FALSE; } static gboolean prpl_xfer_write( struct file_transfer *ft, char *buffer, unsigned int len ) { struct prpl_xfer_data *px = ft->data; if( write( px->fd, buffer, len ) != len ) { imcb_file_canceled( px->ic, ft, "Error while writing temporary file" ); return FALSE; } if( lseek( px->fd, 0, SEEK_CUR ) >= ft->file_size ) { close( px->fd ); px->fd = -1; purple_transfer_forward( ft ); imcb_file_finished( px->ic, ft ); px->ft = NULL; } else b_timeout_add( 0, purple_transfer_request_cb, ft ); return TRUE; } PurpleXferUiOps bee_xfer_uiops = { prplcb_xfer_new, prplcb_xfer_destroy, NULL, /* prplcb_xfer_add, */ prplcb_xfer_progress, prplcb_xfer_dbg, prplcb_xfer_cancel_remote, NULL, NULL, prplcb_xfer_dbg, };