source: protocols/purple/ft.c @ 8b91a1f

/***************************************************************************\
*                                                                           *
*  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 "bpurple.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;
        struct purple_data *pd = 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(pd->account),
                   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,
};