source: protocols/purple/ft.c @ feb1bad

/***************************************************************************\
*                                                                           *
*  BitlBee - An IRC to IM gateway                                           *
*  libpurple module - File transfer stuff                                   *
*                                                                           *
*  Copyright 2009-2010 Wilmer van der Gaast <wilmer@gaast.net>              *
*                                                                           *
*  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 along  *
*  with this program; if not, write to the Free Software Foundation, Inc.,  *
*  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.              *
*                                                                           *
\***************************************************************************/

/* Do file transfers via disk for now, since libpurple was really designed
   for straight-to/from disk fts and is only just learning how to pass the
   file contents the the UI instead (2.6.0 and higher it seems, and with
   varying levels of success). */

#include "bitlbee.h"

#include <stdarg.h>

#include <glib.h>
#include <purple.h>

struct prpl_xfer_data
{
        PurpleXfer *xfer;
        file_transfer_t *ft;
        struct im_connection *ic;
        int fd;
        char *fn, *handle;
        gboolean ui_wants_data;
};

static file_transfer_t *next_ft;

struct im_connection *purple_ic_by_pa( PurpleAccount *pa );
static gboolean prplcb_xfer_new_send_cb( gpointer data, gint fd, b_input_condition cond );
static gboolean prpl_xfer_write_request( struct file_transfer *ft );


/* Receiving files (IM->UI): */
static void prpl_xfer_accept( struct file_transfer *ft )
{
        struct prpl_xfer_data *px = ft->data;
        purple_xfer_request_accepted( px->xfer, NULL );
        prpl_xfer_write_request( ft );
}

static void prpl_xfer_canceled( struct file_transfer *ft, char *reason )
{
        struct prpl_xfer_data *px = ft->data;
        purple_xfer_request_denied( px->xfer );
}

static void prplcb_xfer_new( PurpleXfer *xfer )
{
        if( purple_xfer_get_type( xfer ) == PURPLE_XFER_RECEIVE )
        {
                struct prpl_xfer_data *px = g_new0( struct prpl_xfer_data, 1 );
                
                xfer->ui_data = px;
                px->xfer = xfer;
                px->fn = mktemp( g_strdup( "/tmp/bitlbee-purple-ft.XXXXXX" ) );
                px->fd = -1;
                px->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,
};