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

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* camel-mbox-parser.c : mbox folder parser */

/* 
 *
 * Copyright (C) 1999 Bertrand Guiheneuf <bertrand@helixcode.com> .
 *
 * 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
 */


#include <config.h> 
#include "camel-mbox-parser.h"
#include "camel-log.h"
#include "camel-exception.h"
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/stat.h>
#include <fcntl.h>



#define MBOX_PARSER_BUF_SIZE 1000
 
#define MBOX_PARSER_FROM_KW "from:"               
#define MBOX_PARSER_FROM_KW_SZ 5

#define MBOX_PARSER_DATE_KW "date:"
#define MBOX_PARSER_DATE_KW_SZ 5

#define MBOX_PARSER_X_EVOLUTION_KW "x-evolution:"
#define MBOX_PARSER_X_EVOLUTION_KW_SZ 12

/* the maximum lentgh of all the previous keywords */
#define MBOX_PARSER_MAX_KW_SIZE 12


#define MBOX_PARSER_SUMMARY_SIZE 100






typedef struct {
    
    int fd;                          /* file descriptor of the mbox file */
    guint real_position;             /* real position in the file */

    
    gchar *message_delimiter;        /* message delimiter string */
    guint message_delimiter_length;

    guint message_summary_size;      /* how many characters from the begining of the 
                       mail to put into the message summary */
    
    GArray *preparsed_messages;      /* array of MessagePreParsingInfo */
    CamelMboxParserMessageInfo current_message_info;  /* used to store curent info */
    gboolean is_pending_message;     /* is there some message information pending ? */

    /* buffer info */
    gchar *buffer;                   /* temporary buffer */
    guint left_chunk_size;           /* size of the left chunk in the temp buffer */
    guint last_position;             /* last position that can be compared to a keyword */
    guint current_position;          /* current position in the temp buffer */
    gboolean eof;                    /* did we read the entire file */

    /* other */
    GString *tmp_string;             /* temporary string to fill the headers in */

    
    
} CamelMboxPreParser;


/* clear a preparsing info structure */
static void
clear_message_info (CamelMboxParserMessageInfo *preparsing_info)
{
    preparsing_info->message_position = 0;
    preparsing_info->from = NULL;
    preparsing_info->date = NULL;
    preparsing_info->subject = NULL;
    preparsing_info->status = NULL;
    preparsing_info->priority = NULL;
    preparsing_info->references = NULL;
}



static CamelMboxPreParser *
new_parser (int fd,
        const gchar *message_delimiter) 
{
    
    CamelMboxPreParser *parser;

    parser = g_new0 (CamelMboxPreParser, 1);
    
    parser->fd = fd;
    parser->buffer = g_new (gchar, MBOX_PARSER_BUF_SIZE);
    parser->current_position = 0;
    parser->message_delimiter = g_strdup (message_delimiter);
    parser->message_delimiter_length = strlen (message_delimiter);
    parser->real_position = 0;  
    parser->preparsed_messages = g_array_new (FALSE, FALSE, sizeof (CamelMboxParserMessageInfo));
    parser->message_summary_size = MBOX_PARSER_SUMMARY_SIZE;
    
    parser->left_chunk_size = MAX (parser->message_delimiter_length, MBOX_PARSER_MAX_KW_SIZE);
    parser->eof = FALSE;
    
    parser->tmp_string = g_string_sized_new (1000);

    return parser;
}



/* ** handle exceptions here */
/* read the first chunk of data in the buffer */
static void 
initialize_buffer (CamelMboxPreParser *parser,
           guint first_position)
{
    gint seek_res;
    gint buf_nb_read;

    g_assert (parser);

    /* set the search start position */
    seek_res = lseek (parser->fd, first_position, SEEK_SET);
    //if (seek_res == (off_t)-1) goto io_error;
    
    
    /* the first part of the buffer is filled with newlines, 
       but the next time a chunk of buffer is read, it will
       be filled with the last bytes of the previous chunk. 
       This allows simple g_strcasecmp to test for the presence of 
       the keyword */
    memset (parser->buffer, '\n', parser->left_chunk_size);
    do {
        buf_nb_read = read (parser->fd, parser->buffer + parser->left_chunk_size, 
                    MBOX_PARSER_BUF_SIZE - parser->left_chunk_size);
    } while ((buf_nb_read == -1) && (errno == EINTR));
    /* ** check for an error here */

    parser->last_position = buf_nb_read - parser->left_chunk_size;
    if (buf_nb_read < (MBOX_PARSER_BUF_SIZE - parser->left_chunk_size))
        parser->eof =TRUE;

    parser->current_position = 0;
}




/* read next data in the mbox file */
static void 
read_next_buffer_chunk (CamelMboxPreParser *parser)
{
    gint buf_nb_read;


    g_assert (parser);
    
    /* read the next chunk of data in the folder file  : */
    /*  -   first, copy the last bytes from the previous 
        chunk at the begining of the new one. */
    memcpy (parser->buffer, 
        parser->buffer + MBOX_PARSER_BUF_SIZE - parser->left_chunk_size, 
        parser->left_chunk_size);

    /*  -   then read the next chunk on disk */
    do {
        buf_nb_read = read (parser->fd, 
                    parser->buffer + parser->left_chunk_size, 
                    MBOX_PARSER_BUF_SIZE - parser->left_chunk_size);    
    } while ((buf_nb_read == -1) && (errno == EINTR));
    /* ** check for an error here */


    parser->last_position = buf_nb_read - parser->left_chunk_size;
    if (buf_nb_read < (MBOX_PARSER_BUF_SIZE - parser->left_chunk_size))
        parser->eof =TRUE;

    parser->current_position = 0;
    
}



/* read next char in the buffer */
static void 
goto_next_char (CamelMboxPreParser *parser) 
{   
    if (parser->current_position < parser->last_position)
            parser->current_position++;
    else 
        read_next_buffer_chunk (parser);

    parser->real_position++;
}




static void 
new_message_detected (CamelMboxPreParser *parser)
{
    /* if we were filling a message information 
       save it in the message information array */ 

    if (parser->is_pending_message) {
        g_array_append_vals (parser->preparsed_messages, (gchar *)parser + 
                    G_STRUCT_OFFSET (CamelMboxPreParser, current_message_info), 1);
}
    
    clear_message_info ( &(parser->current_message_info));

    (parser->current_message_info).message_position = parser->real_position;

    parser->is_pending_message = TRUE;
        
}




/* read a header value and put it in the string pointer
   to by header_content */
static void 
read_header (CamelMboxPreParser *parser, gchar **header_content)
{
    gboolean space = FALSE;
    gboolean newline = FALSE;
    gboolean header_end = FALSE;
    gchar *buffer;
    gchar c;
    

    g_assert (parser);

    /* reset the header buffer string */
    parser->tmp_string = g_string_truncate (parser->tmp_string, 0);

    buffer = parser->buffer;

    while (! (parser->eof || header_end) ) {
        
        /* read the current character */
        c = buffer[parser->current_position];
        
        if (space) {
            if (c == ' ' && c == '\t')
                goto next_char;
            else
                space = FALSE;
        }

        if (newline) {
            if (c == ' ' && c == '\t') {

                space = TRUE;
                newline = FALSE;
                goto next_char;
            } else {

                header_end = TRUE;
                continue;
            }
        }

        if (c == '\n') {
            newline = TRUE;
            goto next_char;
        }

        /* feed the header content */
        parser->tmp_string = g_string_append_c (parser->tmp_string, c);

    next_char: /* read next char in the buffer */
        goto_next_char (parser);
    }

    
    /* copy the buffer in the preparsing information structure */
    *header_content = g_strndup (parser->tmp_string->str, parser->tmp_string->len); 
}


/* read the begining of the message and put it in the message
   summary field 
   
*/
static void
read_message_begining (CamelMboxPreParser *parser, gchar **message_summary)
{
    guint nb_read = 0;
    gchar *buffer;
    
    g_assert (parser);
    
    /* reset the header buffer string */
    parser->tmp_string = g_string_truncate (parser->tmp_string, 0);
    
    buffer = parser->buffer;
    /* the message should not be filled character by
       character but there is no g_string_n_append 
       function, so for the moment, this is a lazy 
       implementation */
    while (! (parser->eof) && nb_read<parser->message_summary_size) {

        parser->tmp_string = g_string_append_c (parser->tmp_string, 
                            buffer[parser->current_position]);
        nb_read++;
        goto_next_char (parser);
    }

    *message_summary = g_strndup (parser->tmp_string->str, parser->tmp_string->len);
}








GArray *
camel_mbox_parse_file (int fd, guint start_position, const gchar *message_delimiter)
{
    CamelMboxPreParser *parser;
    gboolean is_parsing_a_message = FALSE;
    gchar c;
    


    /* create the parser */
    parser = new_parser (fd, message_delimiter);
    
    /* initialize the temporary char buffer */
    initialize_buffer (parser, start_position);
    
    while (!parser->eof) {
        
        /* read the current character */
        c = parser->buffer[parser->current_position];
        goto_next_char (parser);
            
        if (c == '\n') {
            
            /* is the next part a message delimiter ? */
            if (g_strncasecmp (parser->buffer + parser->current_position, 
                       parser->message_delimiter, 
                       parser->message_delimiter_length) == 0) {
                
                is_parsing_a_message = TRUE;
                new_message_detected (parser);
                goto_next_char (parser);
                continue;
            }
            
            
            if (is_parsing_a_message) {
                
                /* is the next part a "from" header ? */
                if (g_strncasecmp (parser->buffer + parser->current_position, 
                          MBOX_PARSER_FROM_KW, 
                          MBOX_PARSER_FROM_KW_SZ) == 0) {

                    parser->current_position += MBOX_PARSER_FROM_KW_SZ;
                    read_header (parser, (gchar **) ((gchar *)parser +
                             G_STRUCT_OFFSET (CamelMboxPreParser, current_message_info) + 
                             G_STRUCT_OFFSET (CamelMboxParserMessageInfo, from)));
                    continue;
                }

                /* is it an empty line ? */
                if (parser->buffer[parser->current_position] == '\n') {
                    
                    goto_next_char (parser);
                    read_message_begining (parser,  (gchar **) ((gchar *)parser +
                                   G_STRUCT_OFFSET (CamelMboxPreParser, current_message_info) + 
                                   G_STRUCT_OFFSET (CamelMboxParserMessageInfo, body_summary)));
                    is_parsing_a_message = FALSE;
                }
                    
            }
        }
        
    }
    
    /* if there is a pending message information put it in the array */
    if (parser->is_pending_message) {
        g_array_append_vals (parser->preparsed_messages, (gchar *)parser + 
                     G_STRUCT_OFFSET (CamelMboxPreParser, current_message_info), 1);    
    }
    
    /* free the parser */
    /* ** FIXME : FREE THE PARSER */

    return parser->preparsed_messages;
    
}










#ifdef MBOX_PARSER_TEST
/* to build the test : 
   gcc -o test_parser -DMBOX_PARSER_TEST -I ../.. -I ../../.. \
   -I /usr/lib/glib/include camel-mbox-parser.c \
   -lglib ../../.libs/libcamel.a

   
 */
   
int 
main (int argc, char **argv)
{
    int test_file_fd;
    int i;
    GArray *message_positions; 
    CamelMboxParserMessageInfo *message_info;


    test_file_fd = open (argv[1], O_RDONLY);
    message_positions = camel_mbox_parse_file (test_file_fd, 
                           0,
                           "From ");

    printf ("Found %d messages \n", message_positions->len);
    
#if 0
    for (i=0; i<message_positions->len; i++) {
        //message_info = g_array_index(message_positions, CamelMboxParserMessageInfo, i);
        message_info = ((CamelMboxParserMessageInfo *)(message_positions->data)) + i;
        printf ("\n\n** Message %d : \n", i);
        printf ("\t From: %s\n", message_info->from) ;
        printf ("\t Summary: %s\n", message_info->body_summary) ;
    }
#endif
}




#endif /* MBOX_PARSER_TEST */