path: root/camel/providers/mbox/camel-mbox-utils.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* Various utilities for the mbox provider */

/* 
 * Authors : 
 *   Bertrand Guiheneuf <bertrand@helixcode.com>
 *
 * Copyright (C) 1999 Helix Code.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 */


/* "xev" stands for x-evolution, which is the name of the
 * evolution specific header where are stored informations
 * like : 
 *   - mail status 
 *   - mail uid 
 *  ...
 *
 *
 * The evolution line ha10s the following format :
 *
 *   X-Evolution:XXXXX-X
 *               \___/ \/
 *          UID ---'    `- Status 
 * 
 * the UID is internally used as a 32 bits long integer, but only the first 24 bits are 
 * used. The UID is coded as a string on 4 characters. Each character is a 6 bits 
 * integer coded using the b64 alphabet. 
 *
 */


#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>


#include <glib.h>
#include "camel-mbox-utils.h"
#include "camel-mbox-parser.h"



static gchar b64_alphabet[64] = 
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";



static void 
uid_to_string (guint32 uid, gchar string[4])
{
    
    string [0] = b64_alphabet [(uid >> 18) & 0x3f];
    string [1] = b64_alphabet [(uid >> 12) & 0x3f];
    string [2] = b64_alphabet [(uid >>  6) & 0x3f];
    string [3] = b64_alphabet [(uid      ) & 0x3f];
}


static guint32
string_to_uid (gchar *string)
{
    guint32 i;
    
    i = 
        (((string [0] >= 97) ? ( string [0] - 71 ) :
         ((string [0] >= 65) ? ( string [0] - 65 ) :
          ((string [0] >= 48) ? ( string [0] + 4 ) :
           ((string [0] == 43) ? 62 : 63 )))) << 18)        
        
        + (((string [1] >= 97) ? ( string [1] - 71 ) :
           ((string [1] >= 65) ? ( string [1] - 65 ) :
            ((string [1] >= 48) ? ( string [1] + 4 ) :
             ((string [1] == 43) ? 62 : 63 )))) << 12)
        
        
        + ((((string [2] >= 97) ? ( string [2] - 71 ) :
           ((string [2] >= 65) ? ( string [2] - 65 ) :
            ((string [2] >= 48) ? ( string [2] + 4 ) :
             ((string [2] == 43) ? 62 : 63 ))))) << 6)
        
        
        + (((string [3] >= 97) ? ( string [3] - 71 ) :
           ((string [3] >= 65) ? ( string [3] - 65 ) :
            ((string [3] >= 48) ? ( string [3] + 4 ) :
             ((string [3] == 43) ? 62 : 63 )))));
    
    return i;
    
}


static gchar
flag_to_string (guchar status)
{
    return b64_alphabet [status & 0x3f];
}


static guchar
string_to_flag (gchar string)
{   
    return (string >= 97) ? ( string - 71 ) :
        ((string >= 65) ? ( string - 65 ) :
         ((string >= 48) ? ( string + 4 ) :
          ((string == 43) ? 62 : 63 )));
}





void 
camel_mbox_xev_parse_header_content (gchar header_content[6], 
                     guint32 *uid, 
                     guchar status)
{
    
    /* we assume that the first 4 characters of the header content 
       are actually the uid stuff. If somebody messed with it ...
       toooo bad. 
    */
    *uid = string_to_uid (header_content);
    status = string_to_flag (header_content[5]);
}

void 
camel_mbox_xev_write_header_content (gchar header_content[6], 
                     guint32 uid, 
                     guchar status)
{
    uid_to_string (uid, header_content);
    header_content[5] = flag_to_string (status);
    header_content[4] = '-';
}






static void 
copy_file_chunk (gint fd_src,
         gint fd_dest, 
         glong nb_bytes, 
         CamelException *ex)
{
    gchar buffer [1000];
    glong nb_to_read;
    glong nb_read, v;
    
    
    nb_to_read = nb_bytes;
    while (nb_to_read > 0) {
        
        do {
            nb_read = read (fd_src, buffer, MIN (1000, nb_to_read));
        } while (nb_read == -1 && errno == EINTR);
        
        if (nb_read == -1) {
            camel_exception_set (ex, 
                         CAMEL_EXCEPTION_FOLDER_INSUFFICIENT_PERMISSION,
                         "could read from the mbox file");
            return;
        }


        nb_to_read -= nb_read;

        do {
            v = write (fd_dest, buffer, nb_read);
        } while (v == -1 && errno == EINTR);

        if (v == -1) {
            camel_exception_setv (ex, 
                         CAMEL_EXCEPTION_FOLDER_INSUFFICIENT_PERMISSION,
                         "could not write to the mbox copy file\n"
                          "Full error is : %s\n",
                          strerror (errno));
            return;
        }

        
    }
    
    
    
}


glong
camel_mbox_write_xev (gchar *mbox_file_name,
              GArray *summary_information, 
              glong  next_uid, 
              CamelException *ex)
{
    gint cur_msg;
    CamelMboxParserMessageInfo *cur_msg_info;
    gint fd1, fd2;
    guint bytes_to_copy = 0;
    glong cur_pos = 0;
    glong cur_offset = 0;
    glong end_of_last_message;
    glong next_free_uid;
    gchar xev_header[20] = "X-Evolution:XXXX-X\n";
    gchar *tmp_file_name;
    gchar *tmp_file_name_secure;
    gint rename_result;
    gint unlink_result;
    
    tmp_file_name = g_strdup_printf ("%s__.ev_tmp", mbox_file_name);
    tmp_file_name_secure = g_strdup_printf ("%s__.ev_tmp_secure", mbox_file_name);

    fd1 = open (mbox_file_name, O_RDONLY);
    fd2 = open (tmp_file_name, O_WRONLY | O_CREAT | O_TRUNC );
    if (fd2 == -1) {
            camel_exception_setv (ex, 
                         CAMEL_EXCEPTION_FOLDER_INSUFFICIENT_PERMISSION,
                         "could not create the temporary mbox copy file\n"
                          "\t%s\n"
                          "Full error is : %s\n",
                          tmp_file_name,
                          strerror (errno));
            return next_uid;
        }
    
    next_free_uid = next_uid;
    for (cur_msg = 0; cur_msg < summary_information->len; cur_msg++) {
        
        cur_msg_info = (CamelMboxParserMessageInfo *)(summary_information->data) + cur_msg;
        end_of_last_message = cur_msg_info->message_position + cur_msg_info->size;

        if ( !cur_msg_info->x_evolution) {
            
            bytes_to_copy = cur_msg_info->message_position 
                + cur_msg_info->end_of_headers_offset
                - cur_pos;

            cur_pos = cur_msg_info->message_position 
                + cur_msg_info->end_of_headers_offset;

            copy_file_chunk (fd1, fd2, bytes_to_copy, ex);
            if (camel_exception_get_id (ex)) {
                close (fd1);
                close (fd2);
                goto end;
            }
            
            printf ("Writing the x-ev header\n");
            printf ("Current message number : %d\n", cur_msg);
            camel_mbox_xev_write_header_content (xev_header + 12, next_free_uid++, 0);
            write (fd2, xev_header, 19);
            cur_offset += 19;
            cur_msg_info->size += 19;
            cur_msg_info->x_evolution_offset = cur_msg_info->end_of_headers_offset;
            cur_msg_info->x_evolution = g_strdup_printf ("%.6s", xev_header + 12);
            cur_msg_info->end_of_headers_offset += 19;
        } 
        cur_msg_info->message_position += cur_offset;
    }

    bytes_to_copy = end_of_last_message - cur_pos;
        copy_file_chunk (fd1, fd2, bytes_to_copy, ex);


    /* close the original file as well as the 
       newly created one */
    close (fd1);
    close (fd2);
    


    /* replace the mbox file with the temporary
       file we just created */ 

    /* first rename the old mbox file to a temporary file */
    rename_result = rename (mbox_file_name, tmp_file_name_secure);
    if (rename_result == -1) {
        camel_exception_set (ex, 
                     CAMEL_EXCEPTION_FOLDER_INSUFFICIENT_PERMISSION,
                     "could not rename the mbox file to a temporary file");
        goto end;
    }
    
    /* then rename the newly created mbox file to the name 
       of the original one */
    rename_result = rename (tmp_file_name, mbox_file_name);
    if (rename_result == -1) {
        camel_exception_set (ex, 
                     CAMEL_EXCEPTION_FOLDER_INSUFFICIENT_PERMISSION,
                     "could not rename the X-Evolution fed file to the mbox file");
        goto end;
    }

    /* finally, remove the old renamed mbox file */
    unlink_result = unlink (tmp_file_name_secure);
    if (unlink_result == -1) {
        camel_exception_set (ex, 
                     CAMEL_EXCEPTION_FOLDER_INSUFFICIENT_PERMISSION,
                     "could not remove the saved original mbox file");
        goto end;
    }


 end: /* free everything and return */
    
    g_free (tmp_file_name);
    g_free (tmp_file_name_secure);
    return next_free_uid;
}