path: root/camel/camel-formatter.c

 

/*--------------------------------*-C-*---------------------------------*
 *
 * Author :
 *  Matt Loper <matt@helixcode.com>
 *
 *  Copyright 2000, Helix Code, Inc. (http://www.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 Street #330, Boston, MA 02111-1307, USA.
 *
 *----------------------------------------------------------------------*/

#include <config.h>
#include "camel-formatter.h"

#include "camel-log.h"
#include <libgnome/libgnome.h>
#include <ctype.h> // for isprint

/*
 * The CamelFormatter takes a mime message, and produces html from it,
 * through the single function camel_formatter_mime_message_to_html().
 * The flow of execution goes something like this:
 *
 *     camel_formatter_mime_message_to_html()
 *                 |
 *                 V
 *         handle_mime_message()
 *                 |
 *                 V
 *        call_handler_function()
 *
 * Then, 'call_handler_function' acts as a dispatcher, using a
 * hashtable to match a mime type to one of the following functions;
 * note that the below functions sometimes then use
 * 'call_handler_function()' to continue the process recursively.
 */

static void handle_text_plain         (CamelFormatter *formatter,
                           CamelDataWrapper *wrapper);
static void handle_text_html          (CamelFormatter *formatter,
                           CamelDataWrapper *wrapper);
static void handle_image              (CamelFormatter *formatter,
                       CamelDataWrapper *wrapper);
static void handle_mime_message       (CamelFormatter *formatter,
                           CamelDataWrapper *wrapper);
static void handle_multipart_mixed  (CamelFormatter *formatter,
                       CamelDataWrapper *wrapper);
static void handle_multipart_related  (CamelFormatter *formatter,
                       CamelDataWrapper *wrapper);
static void handle_multipart_alternate(CamelFormatter *formatter,
                       CamelDataWrapper *wrapper);
static void handle_unknown_type       (CamelFormatter *formatter,
                       CamelDataWrapper *wrapper);


/* encodes some characters into their 'escaped' version;
 * so '<' turns into '&lt;', and '"' turns into '&quot;' */
static gchar* encode_entities (const guchar *input,
                   guint len,
                   guint *encoded_len_return);


static GtkObjectClass *parent_class = NULL;

static void _finalize (GtkObject *object);

struct _CamelFormatterPrivate {
    CamelMimeMessage *current_root;
    CamelStream *stream;
};

static GHashTable *mime_function_table = NULL;

static void
debug (const gchar *format, ...)
{
    va_list args;
    gchar *string;
    
    g_return_if_fail (format != NULL);
    
    va_start (args, format);
    string = g_strdup_vprintf (format, args);
    va_end (args);
    
    fputs (string, stdout);
    fflush (stdout);
    
    g_free (string);
}


/**
 * camel_formatter_mime_message_to_html: 
 * @formatter: the camel formatter object
 * @mime_message: the input mime message
 * @stream: byte stream where data will be written 
 *
 * Writes a CamelMimeMessage out, as html, into a stream passed in as
 * a parameter.
 **/
void
camel_formatter_mime_message_to_html (CamelFormatter* formatter,
                      CamelMimeMessage* mime_message,
                      CamelStream* stream)
{
    camel_stream_write_string (stream, "<html><body>\n");

    formatter->priv->current_root = mime_message;
    formatter->priv->stream = stream;
    
    handle_mime_message (
        formatter,
        CAMEL_DATA_WRAPPER (mime_message));

    camel_stream_write_string (formatter->priv->stream,
                   "\n</body></html>\n");   
}

/* we're maintaining a hashtable of mimetypes -> functions;
 * those functions have the following signature...*/
typedef void (*mime_handler_fn) (CamelFormatter *formatter,
                 CamelDataWrapper *data_wrapper);

static gchar*
lookup_unique_id (CamelMimeMessage* root, CamelDataWrapper* child)
{
    return "NYI";
}


/* takes a mimetype, calls a function to handle it */
static void
call_handler_function (CamelFormatter* formatter,
               CamelDataWrapper* wrapper,
               gchar* mimetype)
{
    mime_handler_fn handler_function;

    /* try to find a handler function in our own lookup table */
    handler_function = g_hash_table_lookup (
        mime_function_table, mimetype);

    /* If there's no such handler function, try to find bonobo
     * object to show the object */
    if (!handler_function)
    {
        CamelMimeMessage* root = formatter->priv->current_root;
        char* uid = lookup_unique_id (root, wrapper);
        const char* goad_id = gnome_mime_get_value (
            mimetype, "bonobo-goad_id");

        g_assert (root && uid);

        if (goad_id) {
            char* tag = g_strdup_printf (
                "<object classid=\"%s\" uid=\"%s\">",
                goad_id, uid);
            
            camel_stream_write_string (formatter->priv->stream,
                           tag);
        }
        /* we don't know how to show something of this
                   mimetype; punt */
        else {
            debug ("no function or bonobo object found for mimetype \"%s\"\n",
                   mimetype);
            handler_function = handle_unknown_type;
        }
    }
    else {
        (*handler_function)(formatter, wrapper);
    }
}


/*----------------------------------------------------------------------*
 *     Header (ex. "subj:", "from:") helper functions for mime msgs
 *----------------------------------------------------------------------*/

/* This routine was originally written by Daniel Velliard, (C) 1998
   World Wide Web Consortium.

   It will (for example) turn the input 'ab <c>' into 'ab &lt;c&gt;' */
static gchar *
encode_entities (const guchar *input,
         guint len,
         guint *encoded_len_return)
{
    const guchar *cur = input;
    guchar *buffer = NULL;
    guchar *out = NULL;
    gint buffer_size = 0;
    guint count;

    /* Allocate a translation buffer.  */
    buffer_size = 1000;
    buffer = g_malloc (buffer_size);

    out = buffer;
    count = 0;

    while (count < len) {
        if (out - buffer > buffer_size - 100) {
        gint index = out - buffer;

        buffer_size *= 2;
        buffer = g_realloc (buffer, buffer_size);
        out = &buffer[index];
    }

    /* By default one has to encode at least '<', '>', '"' and '&'.  */

    if (*cur == '<') {
        *out++ = '&';
        *out++ = 'l';
        *out++ = 't';
        *out++ = ';';
    } else if (*cur == '>') {
        *out++ = '&';
        *out++ = 'g';
        *out++ = 't';
        *out++ = ';';
    } else if (*cur == '&') {
        *out++ = '&';
        *out++ = 'a';
        *out++ = 'm';
        *out++ = 'p';
        *out++ = ';';
    } else if (*cur == '"') {
        *out++ = '&';
        *out++ = 'q';
        *out++ = 'u';
        *out++ = 'o';
        *out++ = 't';
        *out++ = ';';
    } else if (((*cur >= 0x20) && (*cur < 0x80))
           || (*cur == '\n') || (*cur == '\r') || (*cur == '\t')) {
        /* Default case, just copy. */
        *out++ = *cur;
    } else {
        char buf[10], *ptr;

        g_snprintf(buf, 9, "&#%d;", *cur);

            ptr = buf;
        while (*ptr != 0)
            *out++ = *ptr++;
    }

    cur++;
    count++;
    }

    *out = 0;
    *encoded_len_return = out - buffer;

    return buffer;
}


static void
write_field_to_stream (const gchar* description, const gchar* value,
               CamelStream *stream)
{
    gchar *s;
    guint ev_length;
    gchar* encoded_value = value?encode_entities (
        value, strlen(value), &ev_length):"";
    int i;
    for (i = 0; i < strlen (value); i++)
        if (!isprint(encoded_value[i]))
            encoded_value[i] = 'Z';
    
    g_assert (description && value);
    
    s = g_strdup_printf ("<b>%s</b>: %s<br>\n",
                  description, encoded_value);

    camel_stream_write_string (stream, s);
    g_free (encoded_value);
    g_free (s);
}


static void
write_recipients_to_stream (const gchar* recipient_type,
                const GList* recipients,
                CamelStream* stream)
{
    /* list of recipients, like "elvis@graceland; bart@springfield" */
    gchar *recipients_string = NULL;
    g_assert (recipient_type && stream);
    
    /* Write out each recipient of 'recipient_type' to the stream */
    while (recipients) {
        gchar *old_string = recipients_string;
        recipients_string = g_strdup_printf (
            "%s%s%s",
            old_string?old_string:"",
            old_string?"; ":"",
            (gchar*)recipients->data);

        g_free (old_string);
        
        recipients = recipients->next;
    }
    write_field_to_stream (recipient_type, recipients_string, stream);

    g_free (recipients_string);
    camel_stream_write_string (stream, "<br><br>\n");   
}


static void
write_header_info_to_stream (CamelMimeMessage* mime_message,
                 CamelStream* stream)
{
    gchar *s = NULL;
    const GList *recipients = NULL;

    g_assert (mime_message && stream);

    /* A few fields will probably be available from the mime_message;
       for each one that's available, write it to the output stream
       with a helper function, 'write_field_to_stream'. */
    if ((s = (gchar*)camel_mime_message_get_subject (mime_message))) {
        write_field_to_stream ("Subject: ", s, stream);
    }

    if ((s = (gchar*)camel_mime_message_get_from (mime_message))) {
        write_field_to_stream ("From: ", s, stream);
    }

    if ((s = (gchar*)camel_mime_message_get_received_date (mime_message))) {
        write_field_to_stream ("Received Date: ", s, stream);
    }

    if ((s = (gchar*)camel_mime_message_get_sent_date (mime_message))) {
        write_field_to_stream ("Sent Date: ", s, stream);
    }       
 
    /* Fill out the "To:" recipients line */
    recipients = camel_mime_message_get_recipients (
        mime_message, CAMEL_RECIPIENT_TYPE_TO);
    
    if (recipients)
        write_recipients_to_stream ("To:", recipients, stream);

    /* Fill out the "CC:" recipients line */
    recipients = camel_mime_message_get_recipients (
        mime_message, CAMEL_RECIPIENT_TYPE_CC);
    if (recipients)
        write_recipients_to_stream ("CC:", recipients, stream); 

    /* Fill out the "BCC:" recipients line */
    recipients = camel_mime_message_get_recipients (
        mime_message, CAMEL_RECIPIENT_TYPE_BCC);    
    if (recipients)
        write_recipients_to_stream ("BCC:", recipients, stream);
}

static gint
strcase_equal (gconstpointer v, gconstpointer v2)
{
    return g_strcasecmp ((const gchar*) v, (const gchar*)v2) == 0;
}
 
#define MIME_TYPE_WHOLE(a)  (gmime_content_field_get_mime_type ( \
                                      camel_mime_part_get_content_type (CAMEL_MIME_PART (a))))
#define MIME_TYPE_MAIN(a)  ((camel_mime_part_get_content_type (CAMEL_MIME_PART (a)))->type)
#define MIME_TYPE_SUB(a)   ((camel_mime_part_get_content_type (CAMEL_MIME_PART (a)))->subtype)


/*----------------------------------------------------------------------*
 *                     Mime handling functions
 *----------------------------------------------------------------------*/

static void
handle_text_plain (CamelFormatter *formatter, CamelDataWrapper *wrapper)
{
    CamelSimpleDataWrapper* simple_data_wrapper;
    gchar* text;

    debug ("handle_text_plain: entered\n");

    /* Plain text is embodied in a CamelSimpleDataWrapper */
    g_assert (CAMEL_IS_SIMPLE_DATA_WRAPPER (wrapper));
    simple_data_wrapper = CAMEL_SIMPLE_DATA_WRAPPER (wrapper);

    /* If there's any text, write it to the stream */
    if (simple_data_wrapper->byte_array->len != 0) {
        int returned_strlen;
        debug ("yay, simple_data_wrapper->byte_array->len != 0\n");
        g_assert (simple_data_wrapper->byte_array->data);

        /* replace '<' with '&lt;', etc. */
        text = encode_entities (simple_data_wrapper->byte_array->data,
                    simple_data_wrapper->byte_array->len,
                    &returned_strlen);
                    
        camel_stream_write_string (formatter->priv->stream, text);
        g_free (text);
    }
    else {
        debug ("boo, simple_data_wrapper->byte_array->len == 0\n");
    }

    debug ("handle_text_plain: exiting\n");
}

static void
handle_text_html (CamelFormatter *formatter, CamelDataWrapper *wrapper)
{
    debug ("handle_text_html: entered\n");

    /* TODO: replace 'body' tag with 'table' tag; delete
           everything prior to the 'body' tag */

    debug ("handle_text_html: exiting\n");      
}

static void
handle_image (CamelFormatter *formatter, CamelDataWrapper *wrapper)
{
    gchar* uuid;
    gchar* tag;
    
    debug ("handle_image: entered\n");

    uuid = lookup_unique_id (formatter->priv->current_root, wrapper);
    g_assert (uuid);
    
    tag = g_strdup_printf ("<img src=\"%s\">\n", uuid);
    camel_stream_write_string (formatter->priv->stream, tag);

    g_free (uuid);
    g_free (tag);       
        
    debug ("handle_image: exiting\n");  
}

static void
handle_mime_message (CamelFormatter *formatter,
             CamelDataWrapper *wrapper)
{
    CamelMimeMessage* mime_message =
        CAMEL_MIME_MESSAGE (wrapper);
    
    CamelDataWrapper* message_contents =
        camel_medium_get_content_object (CAMEL_MEDIUM (mime_message));

    debug ("handle_mime_message: entered\n");   
    camel_stream_write_string (formatter->priv->stream,
                   "<table width=95% border=1><tr><td>\n\n");       

    /* write the subj:, to:, from: etc. fields out as html */
    write_header_info_to_stream (mime_message,
                     formatter->priv->stream);

    /* dispatch the correct handler function for the mime type */
    call_handler_function (formatter, message_contents,
                   MIME_TYPE_WHOLE (mime_message));
    
    /* close up the table we opened */
    camel_stream_write_string (formatter->priv->stream,
                   "\n\n</td></tr></table>\n\n");
    
    debug ("handle_mime_message: exiting\n");
}


/*
 * multipart-alternative helper function --
 * returns NULL if no text/html or text/plan msg is found
 */
static CamelMimePart*
find_preferred_displayable_body_part_in_multipart_alternative (
    CamelMultipart* multipart)
{
    int i, max_multiparts;
    CamelMimePart* html_part = NULL;
    CamelMimePart* plain_part = NULL;   

    /* find out out many parts are in it...*/
    max_multiparts = camel_multipart_get_number (multipart);

        /* TODO: DO LEAF-LOOKUP HERE FOR OTHER MIME-TYPES!!! */

    for (i = 0; i < max_multiparts; i++) {
        CamelMimeBodyPart* body_part = camel_multipart_get_part (multipart, i);
        if (strcase_equal (MIME_TYPE_SUB (body_part), "plain")) {
            plain_part = CAMEL_MIME_PART (body_part);
        }
        else if (strcase_equal (MIME_TYPE_SUB (body_part), "html")) {
            html_part = CAMEL_MIME_PART (body_part);
        }
    }

    if (html_part)
        return html_part;
    if (plain_part)
        return plain_part;
    return NULL;
}


static void
handle_multipart_mixed (CamelFormatter *formatter,
            CamelDataWrapper *wrapper)
{
    CamelMultipart* mp = CAMEL_MULTIPART (wrapper);
    debug ("handle_multipart_mixed: entered\n");

    /* TODO: serialize items in CamelMultipart */
    
    debug ("handle_multipart_mixed: exiting\n");    
}

static void
handle_multipart_related (CamelFormatter *formatter,
              CamelDataWrapper *wrapper)
{
    CamelMultipart* mp = CAMEL_MULTIPART (wrapper);
    debug ("handle_multipart_related: entered\n");

    /* TODO: read RFC, in terms of how a one message
             may refer to another object */ 

    debug ("handle_multipart_related: exiting\n");  
}

static void
handle_multipart_alternate (CamelFormatter *formatter,
                CamelDataWrapper *wrapper)
{
    CamelMultipart* mp = CAMEL_MULTIPART (wrapper);
    debug ("handle_multipart_alternate: entered\n");

    /* TODO:
       find_preferred_displayable_body_part_in_multipart_alternate */

    debug ("handle_multipart_alternate: exiting\n");        
}

static void
handle_unknown_type (CamelFormatter *formatter,
             CamelDataWrapper *wrapper)
{
    gchar* tag;
    CamelMimeMessage* root = formatter->priv->current_root;
    char* uid = lookup_unique_id (root, wrapper);   

    debug ("handle_unknown_type: entered\n");
    g_assert (uid);
    
    tag = g_strdup_printf ("<a href=\"camel://%s\">click-me-to-save</a>\n",
                   uid);

    camel_stream_write_string (formatter->priv->stream, tag);

    debug ("handle_unknown_type: exiting\n");
}

/*----------------------------------------------------------------------*
 *                   Standard Gtk+ class functions
 *----------------------------------------------------------------------*/

CamelFormatter*
camel_formatter_new ()
{
    return (gtk_type_new (CAMEL_FORMATTER_TYPE));
}


static void
camel_formatter_class_init (CamelFormatterClass *camel_formatter_class)
{
    GtkObjectClass *gtk_object_class =
        GTK_OBJECT_CLASS (camel_formatter_class);

    parent_class = gtk_type_class (gtk_object_get_type ());

    mime_function_table = g_hash_table_new (g_str_hash, strcase_equal);

#define ADD_HANDLER(a,b) g_hash_table_insert (mime_function_table, a, b)

    /* hook up mime types to functions that handle them */
    ADD_HANDLER ("text/plain", handle_text_plain);
    ADD_HANDLER ("text/html", handle_text_html);
    ADD_HANDLER ("multipart/alternate", handle_multipart_alternate);
    ADD_HANDLER ("multipart/related", handle_multipart_related);
    ADD_HANDLER ("multipart/related", handle_multipart_mixed);  
    ADD_HANDLER ("message/rfc822", handle_mime_message);
    ADD_HANDLER ("image/", handle_image);       

        /* virtual method overload */
    gtk_object_class->finalize = _finalize;
}


static void
camel_formatter_init (gpointer object, gpointer klass) 
{
    CamelFormatter* cmf = CAMEL_FORMATTER (object);
    cmf->priv = g_new (CamelFormatterPrivate, 1);
}

 
GtkType
camel_formatter_get_type (void)
{
    static GtkType camel_formatter_type = 0;
    
    if (!camel_formatter_type)  {
        GtkTypeInfo camel_formatter_info =  
        {
            "CamelFormatter",
            sizeof (CamelFormatter),
            sizeof (CamelFormatterClass),
            (GtkClassInitFunc) camel_formatter_class_init,
            (GtkObjectInitFunc) camel_formatter_init,
                /* reserved_1 */ NULL,
                /* reserved_2 */ NULL,
            (GtkClassInitFunc) NULL,
        };
        
        camel_formatter_type = gtk_type_unique (
            gtk_object_get_type (),
            &camel_formatter_info);
    }
    
    return camel_formatter_type;
}


static void           
_finalize (GtkObject* object)
{
    CamelFormatter *formatter = CAMEL_FORMATTER (object);

    g_free (formatter->priv);
    
    GTK_OBJECT_CLASS (parent_class)->finalize (object);
}