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_SUBJECT_KW "subject:"
#define MBOX_PARSER_SUBJECT_KW_SZ 8

#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 150






typedef struct {
    
    int fd;                          /* file descriptor of the mbox file */
    glong 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->size = 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;
    preparsing_info->body_summary = NULL;
    preparsing_info->end_of_headers_offset = 0;
    
    preparsing_info->x_evolution = NULL;
    preparsing_info->x_evolution_offset = 0;
    /* reparsing_info->x_evolution_length = 0; */
        
}



/**
 * new_parser: create a new parser object
 * @fd: file descriptor opened on the mbox file
 * @message_delimiter: the string that announce the start of a new message.
 * 
 * Create a new parser object. This object is the place where are 
 * stored all the information concerning the parsing process. 
 * 
 * Return value: The newly created parser object.
 **/
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;
}



/**
 * parser_free: free the parser object
 * @parser: the parser objet to free.
 * 
 * it is important to notice that all structures allocated
 * in new_parser () are freed ** EXCEPT ** the message
 * information array, i.e. the preparsed_messages 
 * field. 
 **/
static void 
parser_free (CamelMboxPreParser *parser)
{
    g_free (parser->buffer);
    g_free (parser->message_delimiter);
    g_string_free (parser->tmp_string, TRUE);
    g_free (parser);
    
}




/* ** handle exceptions here */
/**
 * initialize_buffer: read the first chunk of data in the buffer
 * @parser: parser object to fill
 * @first_position: position to start the read at
 * 
 * read the first chunk of data from the mbox file. 
 * 
 **/
static void 
initialize_buffer (CamelMboxPreParser *parser,
           glong 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;

    if (buf_nb_read == 0)
        parser->eof =TRUE;

    parser->current_position = parser->left_chunk_size;
}




/**
 * read_next_buffer_chunk: read the next chunk of data in the mbox file
 * @parser: parser object
 * 
 * read the next chunk of data in the mbox file. 
 * Routine copies the last part of the buffer at 
 * the begining are concatenate the read data to
 * it. This allows strcmp of keywords in the buffer,
 * until the last postion. That means you can 
 * do a strcmp (buffer, keyword) for any of the
 * keyword defined at the begining of this 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;

    if (buf_nb_read == 0)
        parser->eof =TRUE;

    parser->current_position = 0;
    
}



/**
 * goto_next_char: go one postion forward in the buffer
 * @parser: parser object
 * 
 * goto one position forward in the buffer. If necessary, 
 * read the next chunk of data in the file, possibly
 * raising the parser->eof flag. 
 * 
 **/
static void 
goto_next_char (CamelMboxPreParser *parser) 
{   
    if (parser->current_position < parser->last_position - 1)
            parser->current_position++;
    else 
        read_next_buffer_chunk (parser);

    parser->real_position++;
}







/**
 * advance_n_chars: go n positions forward in the buffer.
 * @parser: parser object
 * @n: number of characters to advance. 
 * 
 **/
static void
advance_n_chars (CamelMboxPreParser *parser, guint n) 
{   
    
    gint position_to_the_end;

    position_to_the_end = parser->last_position - parser->current_position;

    if (n < position_to_the_end)
            parser->current_position += n;
    else {
        printf ("Advance %d chars\n", n);
        printf ("Last position = %d\n", parser->last_position);
        printf ("Current position = %d\n", parser->current_position);
        read_next_buffer_chunk (parser);
        parser->current_position = n - position_to_the_end;
        printf ("New position = %d\n", parser->current_position);
    }
    
    parser->real_position += n;
}






/* called when the buffer has detected the begining of 
   a new message. This routine is supposed to simply 
   store the previous message information and 
   clean the temporary structure used to store 
   the informations */


/**
 * new_message_detected: routine to call when a new message has been detected
 * @parser: parser object.
 * 
 * this routine must be called when the keyword determining the 
 * begining of a new message has been detected. It pushes the
 * information fetched for the last message into the message information
 * array. Also, it gets the parser to the end of the line. 
 **/
static void 
new_message_detected (CamelMboxPreParser *parser)
{
    
    gchar c;

    /* if we were filling a message information 
       save it in the message information array */ 

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

    /* go to the end of the line */
    do {

        c = parser->buffer[parser->current_position];
        goto_next_char (parser);    

    } while (c != '\n');
    
    /* save message position in the message information structure */
    (parser->current_message_info).message_position = parser->real_position;

    parser->is_pending_message = TRUE;
        
}







/**
 * read_header: read the header content contained after the current position.
 * @parser: the parser object.
 * @header_content: a pointer on a (char *) variable to feed with the obtained header string. 
 * 
 * This routine must be called when the parser has detected a header 
 * and it wants the header content to be stored. The parser current position 
 * must EXACTELY be located at the begining of the header content line. 
 * For example, if the file contains the line : 
 *     from:Bertrand Guiheneuf <bertrand@helixcode.com>
 *
 * When this routine is called, the parser must be located 
 * on the "B" of "Bertrand".
 * 
 * When this routine returns, the parser is located just 
 * after the "\n" at the end of the 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_message_begining: read the first characters of a message body
 * @parser: parser object
 * @message_summary: a pointer on a (gchar *) variable where the obtained string will be stored. 
 * 
 * Read the first lines of a message. When calling this routine, the
 * parser must be located at the begining of the message body. 
 * 
 * Return value: if the parsing inside this routine last read a newline, then %TRUE is returned, otherwise %FALSE is returned
 **/
static gboolean
read_message_begining (CamelMboxPreParser *parser, gchar **message_summary)
{
    guint nb_read = 0;
    gchar *buffer;
    gboolean new_message = FALSE;
    guint nb_line = 0;
    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_line <2) && (nb_read<parser->message_summary_size) && (!new_message)) {
        
        
        /* test if we are not at the end of the message */
        if (buffer[parser->current_position] == '\n') {
            
            nb_line++;
            goto_next_char (parser);
            if ((parser->eof) || (g_strncasecmp (parser->buffer + parser->current_position, 
                       parser->message_delimiter, 
                       parser->message_delimiter_length) == 0)) {               
                new_message = TRUE;
                continue;
            } else {
                /* we're not at the end, so let's just add the cr to the summary */
                parser->tmp_string = g_string_append_c (parser->tmp_string, 
                            '\n');
                nb_read++;
                continue;               
            }
                
                
        }
        
        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);
    
    return new_message;
}










/**
 * camel_mbox_parse_file: read an mbox file and parse it. 
 * @fd: file descriptor opened on the mbox file.
 * @message_delimiter: character string delimiting the beginig of a new message 
 * @start_position: poition in the file where to start the parsing. 
 * @get_message_summary: should the parser retrieve the begining of the messages
 * @status_callback: function to call peridically to indicate the progress of the parser
 * @status_interval: floating value between 0 and 1 indicate how often to call @status_callback. 
 * @user_data: user data that will be passed to the callback function
 * 
 * This routine parses an mbox file and retreives both the message starting positions and 
 * some of the informations contained in the message. Those informations are mainly 
 * some RFC822 headers values but also (optionally) the first characters of the mail 
 * body. The @get_message_summary parameter allows to enable or disable this option.
 * 
 * 
 * Return value: An array of CamelMboxParserMessageInfo containing the informations on each message parsed in the file
 **/
GArray *
camel_mbox_parse_file (int fd, 
               const gchar *message_delimiter,
               glong start_position,
               gboolean get_message_summary,
               camel_mbox_preparser_status_callback *status_callback,
               double status_interval,
               gpointer user_data)
{
    CamelMboxPreParser *parser;
    gboolean is_parsing_a_message = FALSE;
    gchar c;
    struct stat stat_buf;
    gint fstat_result;
    glong total_file_size;
    int last_status = 0;
    int real_interval;
    gboolean newline;
    GArray *return_value;

    /* get file size */
    fstat_result = fstat (fd, &stat_buf);
    if (fstat_result == -1) {
        g_warning ("Manage exception here \n");
    }
        
    total_file_size = stat_buf.st_size;
    real_interval = status_interval * total_file_size;
    
    
    /* create the parser */
    parser = new_parser (fd, message_delimiter);
    
    /* initialize the temporary char buffer */
    initialize_buffer (parser, start_position);
    
    /* the first line is indeed at the begining of a new line ... */
    newline = TRUE;

    while (!parser->eof) {

        

        
        /* read the current character */
        if (!newline) {
            c = parser->buffer[parser->current_position];
            newline = (c == '\n');
            goto_next_char (parser);
        }
            
        if (newline) {
            
            /* check if we reached a status milestone */
            if ( status_callback && ((parser->real_position - last_status) > real_interval)) {
                last_status += real_interval;
                status_callback ((double)last_status / (double)total_file_size, 
                         user_data);
            }
            
            /* 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);
                newline = TRUE;
                continue;
            }
            
            
            if (is_parsing_a_message) {
                /* we could find the headers in a clever way, like
                   storing them in a list of pair 
                   [keyword, offset_in_CamelMboxParserMessageInfo]
                   I am too busy for now. Contribution welcome */
                   
                /* 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) {
                    
                    advance_n_chars (parser, MBOX_PARSER_FROM_KW_SZ);
                    read_header (parser, (gchar **) ((gchar *)parser +
                             G_STRUCT_OFFSET (CamelMboxPreParser, current_message_info) + 
                             G_STRUCT_OFFSET (CamelMboxParserMessageInfo, from)));
                    
                    newline = TRUE;
                    continue;
                }

                /* is the next part a "Date" header ? */
                if (g_strncasecmp (parser->buffer + parser->current_position, 
                          MBOX_PARSER_DATE_KW, 
                          MBOX_PARSER_DATE_KW_SZ) == 0) {
                    
                    advance_n_chars (parser, MBOX_PARSER_DATE_KW_SZ);
                    read_header (parser, (gchar **) ((gchar *)parser +
                             G_STRUCT_OFFSET (CamelMboxPreParser, current_message_info) + 
                             G_STRUCT_OFFSET (CamelMboxParserMessageInfo, date)));
                    
                    newline = TRUE;
                    continue;
                }


                /* is the next part a "Subject" header ? */
                if (g_strncasecmp (parser->buffer + parser->current_position, 
                          MBOX_PARSER_SUBJECT_KW, 
                          MBOX_PARSER_SUBJECT_KW_SZ) == 0) {

                    advance_n_chars (parser, MBOX_PARSER_SUBJECT_KW_SZ);
                    read_header (parser, (gchar **) ((gchar *)parser +
                             G_STRUCT_OFFSET (CamelMboxPreParser, current_message_info) + 
                             G_STRUCT_OFFSET (CamelMboxParserMessageInfo, subject)));

                    newline = TRUE;
                    continue;
                }


                /* is the next part a "X-evolution" header ? */
                if (g_strncasecmp (parser->buffer + parser->current_position, 
                          MBOX_PARSER_X_EVOLUTION_KW, 
                          MBOX_PARSER_X_EVOLUTION_KW_SZ) == 0) {

                    /* in the case of the evolution private field, we store 
                       the field position as well as its length because 
                       we will have to change them */
                    parser->current_message_info.x_evolution_offset = parser->real_position
                        - parser->current_message_info.message_position;
                    advance_n_chars (parser, MBOX_PARSER_X_EVOLUTION_KW_SZ);
                    read_header (parser, (gchar **) ((gchar *)parser +
                             G_STRUCT_OFFSET (CamelMboxPreParser, current_message_info) + 
                             G_STRUCT_OFFSET (CamelMboxParserMessageInfo, x_evolution)));

                    /* 
                       parser->current_message_info.x_evolution_length = 
                       parser->real_position - parser->current_message_info.x_evolution_position;
                    */
                    newline = TRUE;
                    continue;
                }


                

                /* is it an empty line ? */
                if (parser->buffer[parser->current_position] == '\n') {
                    
                    parser->current_message_info.end_of_headers_offset = 
                        parser->real_position - parser->current_message_info.message_position;

                    goto_next_char (parser);
                    if (get_message_summary)
                        newline = 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;
                    continue;
                }
            }
            newline = 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);    
    }

    return_value = parser->preparsed_messages;

    /* free the parser */
    parser_free (parser);

    return return_value;
}










#ifdef MBOX_PARSER_TEST
/* to build the test : 
   
   gcc -O3 -I/opt/gnome/lib/glib/include  `glib-config --cflags` -o test_parser -DMBOX_PARSER_TEST -I ../.. -I ../../..  -I /usr/lib/glib/include camel-mbox-parser.c  `glib-config --libs` -lm

   
 */


#include <math.h>

static void 
status (double done, gpointer user_data)
{
    printf ("%d %% done\n", (int)floor (done * 100));
}
int 
main (int argc, char **argv)
{
    int test_file_fd;
    int i;
    GArray *message_positions; 
    CamelMboxParserMessageInfo *message_info;
    gchar tmp_buffer[50];

    tmp_buffer[49] = '\0';

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

                           0,
                           TRUE,
                           status,
                           0.05,
                           NULL);

    printf ("Found %d messages \n", message_positions->len);
    

    for (i=0; i<message_positions->len; i++) {
        
        message_info = ((CamelMboxParserMessageInfo *)(message_positions->data)) + i;
        printf ("\n\n** Message %d : \n", i);
        printf ("Size : %d\n", message_info->size);
        printf ("From: %s\n", message_info->from);
        printf ("Date: %s\n", message_info->date);
        printf ("Subject: %s\n", message_info->subject);
        printf ("Summary: %s\n", message_info->body_summary) ;
        

        lseek (test_file_fd, message_info->message_position, SEEK_SET);
        read (test_file_fd, tmp_buffer, 49);
        printf ("File content at position %d : \n===\n%s\n===\n", message_info->message_position, tmp_buffer);
        
    }



    return 0;
}




#endif /* MBOX_PARSER_TEST */