path: root/mail/mail-format.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */

/*
 * Authors:
 *  Matt Loper <matt@helixcode.com>
 *  Dan Winship <danw@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 "mail-format.h"
#include "mail-display.h"
#include "mail-identify.h"
#include "camel/hash-table-utils.h"
#include "e-util/e-html-utils.h"

#include <libgnome/libgnome.h>
#include <bonobo.h>
#include <libgnorba/gnorba.h>
#include <bonobo/bonobo-stream-memory.h>

#include <ctype.h>    /* for isprint */
#include <string.h>   /* for strstr  */
#include <fcntl.h>

static void handle_text_plain            (CamelMimePart *part,
                      CamelMimeMessage *root,
                      GtkBox *box);
static void handle_text_plain_flowed     (CamelMimePart *part,
                      CamelMimeMessage *root,
                      GtkBox *box);
static void handle_text_enriched         (CamelMimePart *part,
                      CamelMimeMessage *root,
                      GtkBox *box);
static void handle_text_html             (CamelMimePart *part,
                      CamelMimeMessage *root,
                      GtkBox *box);
static void handle_image                 (CamelMimePart *part,
                      CamelMimeMessage *root,
                      GtkBox *box);
static void handle_multipart_mixed       (CamelMimePart *part,
                      CamelMimeMessage *root,
                      GtkBox *box);
static void handle_multipart_related     (CamelMimePart *part,
                      CamelMimeMessage *root,
                      GtkBox *box);
static void handle_multipart_alternative (CamelMimePart *part,
                      CamelMimeMessage *root,
                      GtkBox *box);
static void handle_multipart_appledouble (CamelMimePart *part,
                      CamelMimeMessage *root,
                      GtkBox *box);
static void handle_audio                 (CamelMimePart *part,
                      CamelMimeMessage *root,
                      GtkBox *box);
static void handle_message_rfc822        (CamelMimePart *part,
                      CamelMimeMessage *root,
                      GtkBox *box);

static void handle_unknown_type          (CamelMimePart *part,
                      CamelMimeMessage *root,
                      GtkBox *box);
static void handle_via_bonobo            (CamelMimePart *part,
                      CamelMimeMessage *root,
                      GtkBox *box);

/* writes the header info for a mime message into an html stream */
static void write_headers (CamelMimeMessage *mime_message, GtkBox *box);

/* dispatch html printing via mimetype */
static void call_handler_function (CamelMimePart *part,
                   CamelMimeMessage *root,
                   GtkBox *box);



/**
 * mail_format_mime_message: 
 * @mime_message: the input mime message
 * @box: GtkBox to stack elements into.
 *
 * Writes a CamelMimeMessage out, as a series of GtkHTML objects,
 * into the provided box.
 **/
void
mail_format_mime_message (CamelMimeMessage *mime_message, GtkBox *box)
{
    g_return_if_fail (CAMEL_IS_MIME_MESSAGE (mime_message));
    g_return_if_fail (GTK_IS_BOX (box));

    write_headers (mime_message, box);
    call_handler_function (CAMEL_MIME_PART (mime_message),
                   mime_message, box);
}

static char *
get_cid (CamelMimePart *part, CamelMimeMessage *root)
{
    CamelDataWrapper *wrapper =
        camel_medium_get_content_object (CAMEL_MEDIUM (part));
    char *cid;
    const char *filename;

    /* If we have a real Content-ID, use it. If we don't,
     * make a (syntactically invalid) fake one.
     */
    if (camel_mime_part_get_content_id (part))
        cid = g_strdup (camel_mime_part_get_content_id (part));
    else
        cid = g_strdup_printf ("@@@%p", wrapper);

    gtk_object_set_data (GTK_OBJECT (root), cid, wrapper);

    /* Record the filename, in case the user wants to save this
     * data later.
     */
    filename = camel_mime_part_get_filename (part);
    if (filename) {
        char *safe, *p;

        safe = strrchr (filename, '/');
        if (safe)
            safe = g_strdup (safe + 1);
        else
            safe = g_strdup (filename);

        for (p = safe; *p; p++) {
            if (!isascii ((unsigned char)*p) ||
                strchr (" /'\"`&();|<>${}!", *p))
                *p = '_';
        }

        gtk_object_set_data (GTK_OBJECT (wrapper), "filename", safe);
    }

    return cid;
}


/* We're maintaining a hashtable of mimetypes -> functions;
 * Those functions have the following signature...
 */
typedef void (*mime_handler_fn) (CamelMimePart *part, CamelMimeMessage *root, GtkBox *box);

static GHashTable *mime_function_table, *mime_fallback_table;

static void
setup_function_table (void)
{
    mime_function_table = g_hash_table_new (g_str_hash, g_str_equal);
    mime_fallback_table = g_hash_table_new (g_str_hash, g_str_equal);

    g_hash_table_insert (mime_function_table, "text/plain",
                 handle_text_plain);
    g_hash_table_insert (mime_function_table, "text/richtext",
                 handle_text_enriched);
    g_hash_table_insert (mime_function_table, "text/enriched",
                 handle_text_enriched);
    g_hash_table_insert (mime_function_table, "text/html",
                 handle_text_html);

    g_hash_table_insert (mime_function_table, "image/*",
                 handle_image);

    g_hash_table_insert (mime_function_table, "audio/*",
                 handle_audio);

    g_hash_table_insert (mime_function_table, "message/rfc822",
                 handle_message_rfc822);

    g_hash_table_insert (mime_function_table, "multipart/alternative",
                 handle_multipart_alternative);
    g_hash_table_insert (mime_function_table, "multipart/related",
                 handle_multipart_related);
    g_hash_table_insert (mime_function_table, "multipart/mixed",
                 handle_multipart_mixed);
    g_hash_table_insert (mime_function_table, "multipart/appledouble",
                 handle_multipart_appledouble);

    /* RFC 2046 says unrecognized text subtypes can be treated
     * as text/plain (as long as you recognize the character set),
     * and unrecognized multipart subtypes as multipart/mixed.
     */
    g_hash_table_insert (mime_fallback_table, "text/*",
                 handle_text_plain);
    g_hash_table_insert (mime_function_table, "multipart/*",
                 handle_multipart_mixed);
}

static mime_handler_fn
lookup_handler (const char *mime_type, gboolean *generic)
{
    mime_handler_fn handler_function;
    const char *whole_goad_id, *generic_goad_id;
    char *mime_type_main;

    if (mime_function_table == NULL)
        setup_function_table ();

    mime_type_main = g_strdup_printf ("%.*s/*",
                      (int)strcspn (mime_type, "/"),
                      mime_type);

    /* OK. There are 6 possibilities, which we try in this order:
     *   1) full match in the main table
     *   2) partial match in the main table
     *   3) full match in bonobo
     *   4) full match in the fallback table
     *   5) partial match in the fallback table
     *   6) partial match in bonobo
     *
     * Of these, 1-4 are considered exact matches, and 5 and 6 are
     * considered generic.
     */

    /* Check for full match in mime_function_table. */
    handler_function = g_hash_table_lookup (mime_function_table,
                        mime_type);
    if (!handler_function) {
        handler_function = g_hash_table_lookup (mime_function_table,
                            mime_type_main);
        if (handler_function) {
            /* Optimize this for the next time through. */
            g_hash_table_insert (mime_function_table,
                         g_strdup (mime_type),
                         handler_function);
        }
    }

    if (handler_function) {
        g_free (mime_type_main);
        *generic = FALSE;
        return handler_function;
    }

    whole_goad_id = gnome_mime_get_value (mime_type, "bonobo-goad-id");
    generic_goad_id = gnome_mime_get_value (mime_type_main,
                        "bonobo-goad-id");

    if (whole_goad_id && (!generic_goad_id ||
                  strcmp (whole_goad_id, generic_goad_id) != 0)) {
        /* Optimize this for the next time through. */
        g_hash_table_insert (mime_function_table,
                     g_strdup (mime_type),
                     handle_via_bonobo);
        g_free (mime_type_main);
        *generic = FALSE;
        return handle_via_bonobo;
    }

    handler_function = g_hash_table_lookup (mime_fallback_table,
                        mime_type);
    if (handler_function)
        *generic = FALSE;
    else {
        handler_function = g_hash_table_lookup (mime_fallback_table,
                            mime_type_main);
        if (!handler_function && generic_goad_id)
            handler_function = handle_via_bonobo;
        *generic = TRUE;
    }

    g_free (mime_type_main);
    return handler_function;
}

static void
call_handler_function (CamelMimePart *part, CamelMimeMessage *root,
               GtkBox *box)
{
    CamelDataWrapper *wrapper;
    mime_handler_fn handler_function = NULL;
    gboolean generic;
    char *mime_type;

    wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (part));
    mime_type = camel_data_wrapper_get_mime_type (wrapper);
    g_strdown (mime_type);
    handler_function = lookup_handler (mime_type, &generic);
    g_free (mime_type);

    if (handler_function)
        (*handler_function) (part, root, box);
    else
        handle_unknown_type (part, root, box);
}

static void
write_field_to_stream (const char *description, const char *value,
               gboolean bold, GtkHTML *html,
               GtkHTMLStreamHandle *stream)
{
    char *encoded_value;

    if (value) {
        unsigned char *p;

        encoded_value = e_text_to_html (value,
                        E_TEXT_TO_HTML_CONVERT_NL |
                        E_TEXT_TO_HTML_CONVERT_URLS);
        for (p = (unsigned char *)encoded_value; *p; p++) {
            if (!isprint (*p))
                *p = '?';
        }
    } else
        encoded_value = "";

    mail_html_write (html, stream,
             "<tr valign=top><%s align=right>%s</%s>"
             "<td>%s</td></tr>", bold ? "th" : "td",
             description, bold ? "th" : "td", encoded_value);
    if (value)
        g_free (encoded_value);
}

static void
write_recipients_to_stream (const gchar *recipient_type,
                const CamelInternetAddress *recipients,
                gboolean bold, GtkHTML *html,
                GtkHTMLStreamHandle *stream)
{
    int i;
    char *recipients_string = NULL;
    const char *name, *addr;

    i = 0;
    while (camel_internet_address_get (recipients, i++, &name, &addr)) {
        char *old_string = recipients_string;
        recipients_string =
            g_strdup_printf ("%s%s%s%s%s <%s>",
                     old_string ? old_string : "",
                     old_string ? ", " : "",
                     *name ? "\"" : "", name,
                     *name ? "\"" : "", addr);
        g_free (old_string);
    }

    write_field_to_stream (recipient_type, recipients_string,
                   bold, html, stream);
    g_free (recipients_string);
}



static void
write_headers (CamelMimeMessage *mime_message, GtkBox *box)
{
    const CamelInternetAddress *recipients;
    GtkHTML *html;
    GtkHTMLStreamHandle *stream;

    mail_html_new (&html, &stream, mime_message, FALSE);
    mail_html_write (html, stream, "%s%s", HTML_HEADER,
             "<BODY TEXT=\"#000000\" BGCOLOR=\"#EEEEEE\">\n");

    mail_html_write (html, stream, "<table>");

    /* 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'.
     */

    write_field_to_stream ("From:",
                   camel_mime_message_get_from (mime_message),
                   TRUE, html, stream);

    if (camel_mime_message_get_reply_to (mime_message)) {
        write_field_to_stream ("Reply-To:",
                       camel_mime_message_get_reply_to (mime_message),
                       FALSE, html, stream);
    }

    write_recipients_to_stream ("To:",
                    camel_mime_message_get_recipients (mime_message, CAMEL_RECIPIENT_TYPE_TO),
                    TRUE, html, stream);

    recipients = camel_mime_message_get_recipients (mime_message, CAMEL_RECIPIENT_TYPE_CC);
    if (recipients)
        write_recipients_to_stream ("Cc:", recipients, TRUE, html, stream);
    write_field_to_stream ("Subject:",
                   camel_mime_message_get_subject (mime_message),
                   TRUE, html, stream);

    mail_html_write (html, stream, "</table>");

    mail_html_end (html, stream, TRUE, box);
}

#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)


static char *
get_data_wrapper_text (CamelDataWrapper *data)
{
    CamelStream *memstream;
    GByteArray *ba;
    char *text;

    ba = g_byte_array_new ();
    memstream = camel_stream_mem_new_with_byte_array (ba);

    camel_data_wrapper_write_to_stream (data, memstream);
    text = g_malloc (ba->len + 1);
    memcpy (text, ba->data, ba->len);
    text[ba->len] = '\0';

    camel_stream_close (memstream);
    return text;
}

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

static void
handle_text_plain (CamelMimePart *part, CamelMimeMessage *root, GtkBox *box)
{
    GtkHTML *html;
    GtkHTMLStreamHandle *stream;
    CamelDataWrapper *wrapper =
        camel_medium_get_content_object (CAMEL_MEDIUM (part));
    char *text, *htmltext;
    GMimeContentField *type;
    const char *format;

    mail_html_new (&html, &stream, root, TRUE);
    mail_html_write (html, stream, "\n<!-- text/plain -->\n<pre>\n");

    /* Check for RFC 2646 flowed text. */
    type = camel_mime_part_get_content_type (part);
    format = gmime_content_field_get_parameter (type, "format");
    if (format && !strcasecmp (format, "flowed")) {
        handle_text_plain_flowed (part, root, box);
        return;
    }

    text = get_data_wrapper_text (wrapper);
    if (text && *text) {
        htmltext = e_text_to_html (text, E_TEXT_TO_HTML_CONVERT_URLS);
        mail_html_write (html, stream, "%s", htmltext);
        g_free (htmltext);
    } else
        mail_html_write (html, stream, "<b>(empty)</b>");
    g_free (text);

    mail_html_write (html, stream, "</pre>\n");
    mail_html_end (html, stream, TRUE, box);
}

static void
handle_text_plain_flowed (CamelMimePart *part, CamelMimeMessage *root,
              GtkBox *box)
{
    GtkHTML *html;
    GtkHTMLStreamHandle *stream;
    CamelDataWrapper *wrapper =
        camel_medium_get_content_object (CAMEL_MEDIUM (part));
    char *text, *line, *p;
    CamelStream *wrapper_output_stream, *buffer;
    int prevquoting = 0, quoting, len;
    gboolean br_pending = FALSE;

    mail_html_new (&html, &stream, root, TRUE);
    mail_html_write (html, stream,
             "\n<!-- text/plain, flowed -->\n<tt>\n");

    /* Get the output stream of the data wrapper. */
    wrapper_output_stream = camel_data_wrapper_get_output_stream (wrapper);
    camel_stream_reset (wrapper_output_stream);
    buffer = camel_stream_buffer_new (wrapper_output_stream,
                      CAMEL_STREAM_BUFFER_READ);

    do {
        /* Read next chunk of text. */
        line = camel_stream_buffer_read_line (
            CAMEL_STREAM_BUFFER (buffer));
        if (!line)
            break;

        quoting = 0;
        for (p = line; *p == '>'; p++)
            quoting++;
        if (quoting != prevquoting) {
            mail_html_write (html, stream, "%s\n",
                     prevquoting == 0 ? "<i>\n" : "");
            while (quoting > prevquoting) {
                mail_html_write (html, stream, "<blockquote>");
                prevquoting++;
            }
            while (quoting < prevquoting) {
                mail_html_write (html, stream,
                         "</blockquote>");
                prevquoting--;
            }
            mail_html_write (html, stream, "%s\n",
                     prevquoting == 0 ? "</i>\n" : "");
        } else if (br_pending) {
            mail_html_write (html, stream, "<br>\n");
            br_pending = FALSE;
        }

        if (*p == ' ')
            p++;

        /* replace '<' with '&lt;', etc. */
        text = e_text_to_html (p, E_TEXT_TO_HTML_CONVERT_SPACES |
                       E_TEXT_TO_HTML_CONVERT_URLS);
        if (text && *text)
            mail_html_write (html, stream, "%s", text);
        g_free (text);

        len = strlen (p);
        if (len == 0 || p[len - 1] != ' ' || !strcmp (p, "-- "))
            br_pending = TRUE;
        g_free (line);
    } while (!camel_stream_eos (buffer));

    camel_stream_close (buffer);

    mail_html_write (html, stream, "</tt>\n");
    mail_html_end (html, stream, TRUE, box);
}

/* text/enriched (RFC 1896) or text/richtext (included in RFC 1341) */
static void
handle_text_enriched (CamelMimePart *part, CamelMimeMessage *root, GtkBox *box)
{
    static GHashTable *translations = NULL;
    GtkHTML *html;
    GtkHTMLStreamHandle *stream;
    CamelDataWrapper *wrapper =
        camel_medium_get_content_object (CAMEL_MEDIUM (part));
    CamelStream *memstream;
    GByteArray *ba;
    char *p;
    int len, nofill = 0;

    if (!translations) {
        translations = g_hash_table_new (g_strcase_hash,
                         g_strcase_equal);
        g_hash_table_insert (translations, "bold", "<b>");
        g_hash_table_insert (translations, "/bold", "</b>");
        g_hash_table_insert (translations, "italic", "<i>");
        g_hash_table_insert (translations, "/italic", "</i>");
        g_hash_table_insert (translations, "fixed", "<tt>");
        g_hash_table_insert (translations, "/fixed", "</tt>");
        g_hash_table_insert (translations, "smaller", "<font size=-1>");
        g_hash_table_insert (translations, "/smaller", "</font>");
        g_hash_table_insert (translations, "bigger", "<font size=+1>");
        g_hash_table_insert (translations, "/bigger", "</font>");
        g_hash_table_insert (translations, "underline", "<u>");
        g_hash_table_insert (translations, "/underline", "</u>");
        g_hash_table_insert (translations, "center", "<p align=center>");
        g_hash_table_insert (translations, "/center", "</p>");
        g_hash_table_insert (translations, "flushleft", "<p align=left>");
        g_hash_table_insert (translations, "/flushleft", "</p>");
        g_hash_table_insert (translations, "flushright", "<p align=right>");
        g_hash_table_insert (translations, "/flushright", "</p>");
        g_hash_table_insert (translations, "excerpt", "<blockquote>");
        g_hash_table_insert (translations, "/excerpt", "</blockquote>");
        g_hash_table_insert (translations, "paragraph", "<p>");
        g_hash_table_insert (translations, "signature", "<address>");
        g_hash_table_insert (translations, "/signature", "</address>");
        g_hash_table_insert (translations, "comment", "<!-- ");
        g_hash_table_insert (translations, "/comment", " -->");
        g_hash_table_insert (translations, "param", "<!-- ");
        g_hash_table_insert (translations, "/param", " -->");
        g_hash_table_insert (translations, "nl", "<br>");
        g_hash_table_insert (translations, "np", "<hr>");
    }

    mail_html_new (&html, &stream, root, TRUE);
    mail_html_write (html, stream, "\n<!-- text/enriched -->\n");

    ba = g_byte_array_new ();
    memstream = camel_stream_mem_new_with_byte_array (ba);
    camel_data_wrapper_write_to_stream (wrapper, memstream);
    g_byte_array_append (ba, "", 1);

    p = ba->data;

    while (p) {
        len = strcspn (p, " <>&\n");
        if (len)
            gtk_html_write (html, stream, p, len);

        p += len;
        if (!*p)
            break;

        switch (*p++) {
        case ' ':
            while (*p == ' ') {
                mail_html_write (html, stream, "&nbsp;");
                p++;
            }
            mail_html_write (html, stream, " ");
            break;

        case '\n':
            mail_html_write (html, stream, " ");
            if (nofill <= 0) {
                while (*p == '\n') {
                    mail_html_write (html, stream, "<br>");
                    p++;
                }
            }
            break;

        case '>':
            mail_html_write (html, stream, "&gt;");
            break;

        case '&':
            mail_html_write (html, stream, "&amp;");
            break;

        case '<':
            if (*p == '<') {
                mail_html_write (html, stream, "&lt;");
                break;
            }

            if (strncmp (p, "lt>", 3) == 0)
                mail_html_write (html, stream, "&lt;");
            else if (strncmp (p, "nofill>", 7) == 0) {
                nofill++;
                mail_html_write (html, stream, "<pre>");
            } else if (strncmp (p, "/nofill>", 8) == 0) {
                nofill--;
                mail_html_write (html, stream, "</pre>");
            } else {
                char *copy, *match;

                len = strcspn (p, ">");
                copy = g_strndup (p, len);
                match = g_hash_table_lookup (translations,
                                 copy);
                g_free (copy);
                if (match) {
                    mail_html_write (html, stream, "%s",
                             match);
                }
            }

            p = strchr (p, '>');
            if (p)
                p++;
        }
    }

    mail_html_end (html, stream, TRUE, box);
}

static void
handle_text_html (CamelMimePart *part, CamelMimeMessage *root, GtkBox *box)
{
    GtkHTML *html;
    GtkHTMLStreamHandle *stream;
    CamelDataWrapper *wrapper =
        camel_medium_get_content_object (CAMEL_MEDIUM (part));
    CamelStream *wrapper_output_stream;
    gchar tmp_buffer[4096];
    gint nb_bytes_read;
    gboolean empty_text = TRUE;

    mail_html_new (&html, &stream, root, FALSE);
    mail_html_write (html, stream, "\n<!-- text/html -->\n");

    /* Get the output stream of the data wrapper. */
    wrapper_output_stream = camel_data_wrapper_get_output_stream (wrapper);
    camel_stream_reset (wrapper_output_stream);

    do {
        /* Read next chunk of text. */
        nb_bytes_read = camel_stream_read (wrapper_output_stream,
                           tmp_buffer, 4096);

        /* If there's any text, write it to the stream */
        if (nb_bytes_read > 0) {
            empty_text = FALSE;
            
            /* Write the buffer to the html stream */
            gtk_html_write (html, stream, tmp_buffer,
                    nb_bytes_read);
        }
    } while (!camel_stream_eos (wrapper_output_stream));

    if (empty_text)
        mail_html_write (html, stream, "<b>(empty)</b>");

    mail_html_end (html, stream, FALSE, box);
}

static void
handle_image (CamelMimePart *part, CamelMimeMessage *root, GtkBox *box)
{
    GtkHTML *html;
    GtkHTMLStreamHandle *stream;
    char *cid;

    cid = get_cid (part, root);
    mail_html_new (&html, &stream, root, TRUE);
    mail_html_write (html, stream, "<img src=\"cid:%s\">", cid);
    mail_html_end (html, stream, TRUE, box);
    g_free (cid);
}

static void
handle_multipart_mixed (CamelMimePart *part, CamelMimeMessage *root, GtkBox *box)
{
    CamelDataWrapper *wrapper =
        camel_medium_get_content_object (CAMEL_MEDIUM (part));
    CamelMultipart *mp;
    int i, nparts;

    g_return_if_fail (CAMEL_IS_MULTIPART (wrapper));
    mp = CAMEL_MULTIPART (wrapper);

    nparts = camel_multipart_get_number (mp);   
    for (i = 0; i < nparts; i++) {
        part = camel_multipart_get_part (mp, i);

        call_handler_function (part, root, box);
    }
}

/* As seen in RFC 2387! */
static void
handle_multipart_related (CamelMimePart *part, CamelMimeMessage *root, GtkBox *box)
{
    CamelDataWrapper *wrapper =
        camel_medium_get_content_object (CAMEL_MEDIUM (part));
    CamelMultipart *mp;
    CamelMimePart *body_part, *display_part = NULL;
    GMimeContentField *content_type;
    const char *start;
    int i, nparts;

    g_return_if_fail (CAMEL_IS_MULTIPART (wrapper));
    mp = CAMEL_MULTIPART (wrapper);
    nparts = camel_multipart_get_number (mp);   

    content_type = camel_mime_part_get_content_type (part);
    start = gmime_content_field_get_parameter (content_type, "start");
    if (start) {
        int len;

        /* The "start" parameter includes <>s, which Content-Id
         * does not.
         */
        len = strlen (start) - 2;

        for (i = 0; i < nparts; i++) {
            const char *cid;

            body_part = camel_multipart_get_part (mp, i);
            cid = camel_mime_part_get_content_id (body_part);

            if (!strncmp (cid, start + 1, len) &&
                strlen (cid) == len) {
                display_part = body_part;
                break;
            }
        }

        if (!display_part) {
            /* Oops. Hrmph. */
            handle_multipart_mixed (part, root, box);
        }
    } else {
        /* No start parameter, so it defaults to the first part. */
        display_part = camel_multipart_get_part (mp, 0);
    }

    /* Record the Content-IDs of any non-displayed parts. */
    for (i = 0; i < nparts; i++) {
        char *cid;

        body_part = camel_multipart_get_part (mp, i);
        if (body_part == display_part)
            continue;

        cid = get_cid (body_part, root);
        g_free (cid);
    }

    /* Now, display the displayed part. */
    call_handler_function (display_part, root, box);
}

/* RFC 2046 says "display the last part that you are able to display". */
static CamelMimePart *
find_preferred_alternative (CamelMultipart *multipart)
{
    int i, nparts;
    CamelMimePart *preferred_part = NULL;
    gboolean generic;

    nparts = camel_multipart_get_number (multipart);
    for (i = 0; i < nparts; i++) {
        CamelMimePart *part = camel_multipart_get_part (multipart, i);
        char *mime_type = gmime_content_field_get_mime_type (
            camel_mime_part_get_content_type (part));

        g_strdown (mime_type);
        if (lookup_handler (mime_type, &generic) &&
            (!preferred_part || !generic))
            preferred_part = part;
        g_free (mime_type);
    }

    return preferred_part;
}

static void
handle_multipart_alternative (CamelMimePart *part, CamelMimeMessage *root,
                  GtkBox *box)
{
    CamelDataWrapper *wrapper =
        camel_medium_get_content_object (CAMEL_MEDIUM (part));
    CamelMultipart *multipart;
    CamelMimePart *mime_part;

    g_return_if_fail (CAMEL_IS_MULTIPART (wrapper));
    multipart = CAMEL_MULTIPART (wrapper);

    mime_part = find_preferred_alternative (multipart); 
    if (mime_part)
        call_handler_function (mime_part, root, box);
    else
        handle_unknown_type (part, root, box);
}

/* RFC 1740 */
static void
handle_multipart_appledouble (CamelMimePart *part, CamelMimeMessage *root,
                  GtkBox *box)
{
    CamelDataWrapper *wrapper =
        camel_medium_get_content_object (CAMEL_MEDIUM (part));
    CamelMultipart *multipart;

    g_return_if_fail (CAMEL_IS_MULTIPART (wrapper));
    multipart = CAMEL_MULTIPART (wrapper);

    /* The first part is application/applefile and is not useful
     * to us. The second part _may_ be displayable data. Most
     * likely it's application/octet-stream though.
     */
    part = camel_multipart_get_part (multipart, 1);
    call_handler_function (part, root, box);
}

static void
handle_mystery (CamelMimePart *part, CamelMimeMessage *root, GtkBox *box,
        char *icon_name, char *id, char *action)
{
    GtkHTML *html;
    GtkHTMLStreamHandle *stream;
    const char *info;
    char *htmlinfo;
    GMimeContentField *content_type;

    mail_html_new (&html, &stream, root, TRUE);
    mail_html_write (html, stream, "<table><tr><td><a href=\"cid:%s\">"
             "<img src=\"x-gnome-icon:%s\"></a></td>"
             "<td>%s<br>", get_cid (part, root), icon_name, id);

    info = camel_mime_part_get_description (part);
    if (info) {
        htmlinfo = e_text_to_html (info, E_TEXT_TO_HTML_CONVERT_URLS);
        mail_html_write (html, stream, "Description: %s<br>",
                 htmlinfo);
        g_free (htmlinfo);
    }

    content_type = camel_mime_part_get_content_type (part);
    info = gmime_content_field_get_parameter (content_type, "name");
    if (!info)
        info = camel_mime_part_get_filename (part);
    if (info) {
        htmlinfo = e_text_to_html (info, 0);
        mail_html_write (html, stream, "Name: %s<br>",
                 htmlinfo);
        g_free (htmlinfo);
    }

    mail_html_write (html, stream,
             "<br>Click on the icon to %s.</td></tr></table>",
             action);
    mail_html_end (html, stream, TRUE, box);
}

static void
handle_audio (CamelMimePart *part, CamelMimeMessage *root, GtkBox *box)
{
    char *id;

    id = g_strdup_printf ("Audio data in \"%s\" format.",
                  camel_mime_part_get_content_type (part)->subtype);
    handle_mystery (part, root, box, "gnome-audio2.png", id, "play it");
    g_free (id);
}

static void
handle_message_rfc822 (CamelMimePart *part, CamelMimeMessage *root,
               GtkBox *box)
{
    CamelDataWrapper *wrapper =
        camel_medium_get_content_object (CAMEL_MEDIUM (part));
    GtkWidget *subbox, *frame;

    g_return_if_fail (CAMEL_IS_MIME_MESSAGE (wrapper));

    subbox = gtk_vbox_new (FALSE, 2);
    mail_format_mime_message (CAMEL_MIME_MESSAGE (wrapper),
                  GTK_BOX (subbox));

    frame = gtk_frame_new (NULL);
    gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
    gtk_container_set_border_width (GTK_CONTAINER (frame), 8);
    gtk_box_pack_start (box, frame, FALSE, FALSE, 0);
    gtk_container_add (GTK_CONTAINER (frame), subbox);
    gtk_widget_show_all (frame);
}

static void
handle_undisplayable (CamelMimePart *part, CamelMimeMessage *root, GtkBox *box)
{
    char *id;

    id = g_strdup_printf ("Unknown data of type \"%s/%s\".",
                  camel_mime_part_get_content_type (part)->type,
                  camel_mime_part_get_content_type (part)->subtype);
    handle_mystery (part, root, box, "gnome-question.png", id,
            "save it to disk");
    g_free (id);
}

static void
handle_unknown_type (CamelMimePart *part, CamelMimeMessage *root, GtkBox *box)
{
    char *type;

    /* Don't give up quite yet. */
    type = mail_identify_mime_part (part);
    if (type) {
        mime_handler_fn handler_function;
        gboolean generic;

        handler_function = lookup_handler (type, &generic);
        g_free (type);
        if (handler_function &&
            handler_function != handle_unknown_type) {
            (*handler_function) (part, root, box);
            return;
        }
    }       

    /* OK. Give up. */
    handle_undisplayable (part, root, box);
}

static void 
embeddable_destroy_cb (GtkObject *obj, gpointer user_data)
{
    BonoboWidget *be;      /* bonobo embeddable */
    BonoboViewFrame *vf;   /* the embeddable view frame */
    BonoboObjectClient* server;
    CORBA_Environment ev;

    be = BONOBO_WIDGET (obj);
    server = bonobo_widget_get_server (be);

    vf = bonobo_widget_get_view_frame (be);
    bonobo_control_frame_control_deactivate (
        BONOBO_CONTROL_FRAME (vf));
    /* w = bonobo_control_frame_get_widget (BONOBO_CONTROL_FRAME (vf)); */
    
    /* gtk_widget_destroy (w); */
    
    CORBA_exception_init (&ev);
    Bonobo_Unknown_unref (
        bonobo_object_corba_objref (BONOBO_OBJECT(server)), &ev);
    CORBA_Object_release (
        bonobo_object_corba_objref (BONOBO_OBJECT(server)), &ev);

    CORBA_exception_free (&ev);
    bonobo_object_destroy (BONOBO_OBJECT (vf));
    /* gtk_object_unref (obj); */
}

static void
handle_via_bonobo (CamelMimePart *part, CamelMimeMessage *root, GtkBox *box)
{
    CamelDataWrapper *wrapper =
        camel_medium_get_content_object (CAMEL_MEDIUM (part));
    GMimeContentField *type;
    char *mimetype;
    const char *goad_id;
    GtkWidget *embedded;
    BonoboObjectClient *server;
    Bonobo_PersistStream persist;   
    CORBA_Environment ev;
    GByteArray *ba;
    CamelStream *cstream;
    BonoboStream *bstream;

    type = camel_data_wrapper_get_mime_type_field (
        camel_medium_get_content_object (CAMEL_MEDIUM (part)));
    mimetype = g_strdup_printf ("%s/%s", type->type, type->subtype);
    goad_id = gnome_mime_get_value (mimetype, "bonobo-goad-id");
    g_free (mimetype);

    if (!goad_id)
        goad_id = gnome_mime_get_value (type->type, "bonobo-goad-id");
    if (!goad_id) {
        handle_undisplayable (part, root, box);
        return;
    }

    embedded = bonobo_widget_new_subdoc (goad_id, NULL);
    if (!embedded) {
        handle_undisplayable (part, root, box);
        return;
    }
    server = bonobo_widget_get_server (BONOBO_WIDGET (embedded));

    persist = (Bonobo_PersistStream) bonobo_object_client_query_interface (
        server, "IDL:Bonobo/PersistStream:1.0", NULL);
    if (persist == CORBA_OBJECT_NIL) {
        bonobo_object_destroy (BONOBO_OBJECT (embedded));
        handle_undisplayable (part, root, box);
        return;
    }

    /* Write the data to a CamelStreamMem... */
    ba = g_byte_array_new ();
    cstream = camel_stream_mem_new_with_byte_array (ba);
    camel_data_wrapper_write_to_stream (wrapper, cstream);

    /* ...convert the CamelStreamMem to a BonoboStreamMem... */
    bstream = bonobo_stream_mem_create (ba->data, ba->len, TRUE, FALSE);
    camel_stream_close (cstream);

    /* ...and hydrate the PersistStream from the BonoboStream. */
    CORBA_exception_init (&ev);
    Bonobo_PersistStream_load (persist,
                   bonobo_object_corba_objref (
                       BONOBO_OBJECT (bstream)),
                   &ev);
    bonobo_object_unref (BONOBO_OBJECT (bstream));
    Bonobo_Unknown_unref (persist, &ev);
    CORBA_Object_release (persist, &ev);

    if (ev._major != CORBA_NO_EXCEPTION) {
        bonobo_object_unref (BONOBO_OBJECT (embedded));
        CORBA_exception_free (&ev);             
        handle_undisplayable (part, root, box);
        return;
    }
    CORBA_exception_free (&ev);             

    /* Embed the widget. */
    gtk_widget_show (embedded);
    gtk_box_pack_start (box, embedded, FALSE, FALSE, 0);
    gtk_signal_connect (GTK_OBJECT (embedded), "destroy",
                embeddable_destroy_cb, NULL);
}


static char *
reply_body (CamelDataWrapper *data, gboolean *html)
{
    CamelMultipart *mp;
    CamelMimePart *subpart;
    int i, nparts;
    char *subtext, *old;
    const char *boundary, *disp;
    char *text = NULL;
    GMimeContentField *mime_type;

    /* We only include text, message, and multipart bodies. */
    mime_type = camel_data_wrapper_get_mime_type_field (data);

    /* FIXME: This is wrong. We don't want to include large
     * images. But if we don't do it this way, we don't get
     * the headers...
     */
    if (strcasecmp (mime_type->type, "message") == 0) {
        *html = FALSE;
        return get_data_wrapper_text (data);
    }

    if (strcasecmp (mime_type->type, "text") == 0) {
        *html = !strcasecmp (mime_type->subtype, "html");
        return get_data_wrapper_text (data);
    }

    /* If it's not message and it's not text, and it's not
     * multipart, we don't want to deal with it.
     */
    if (strcasecmp (mime_type->type, "multipart") != 0)
        return NULL;

    mp = CAMEL_MULTIPART (data);

    if (strcasecmp (mime_type->subtype, "alternative") == 0) {
        /* Pick our favorite alternative and reply to it. */

        subpart = find_preferred_alternative (mp);
        if (!subpart)
            return NULL;

        data = camel_medium_get_content_object (
            CAMEL_MEDIUM (subpart));
        return reply_body (data, html);
    }

    nparts = camel_multipart_get_number (mp);

    /* Otherwise, concatenate all the parts that we can. If we find
     * an HTML part in there though, return just that: We don't want
     * to deal with merging HTML and non-HTML parts.
     */
    boundary = camel_multipart_get_boundary (mp);
    for (i = 0; i < nparts; i++) {
        subpart = camel_multipart_get_part (mp, i);

        disp = camel_mime_part_get_disposition (subpart);
        if (disp && strcasecmp (disp, "inline") != 0)
            continue;

        data = camel_medium_get_content_object (
            CAMEL_MEDIUM (subpart));
        subtext = reply_body (data, html);
        if (!subtext)
            continue;
        if (*html) {
            g_free (text);
            return subtext;
        }

        if (text) {
            old = text;
            text = g_strdup_printf ("%s\n--%s\n%s", text,
                        boundary, subtext);
            g_free (subtext);
            g_free (old);
        } else
            text = subtext;
    }

    if (!text)
        return NULL;

    return text;
}

EMsgComposer *
mail_generate_reply (CamelMimeMessage *message, gboolean to_all)
{
    CamelDataWrapper *contents;
    char *text, *subject;
    EMsgComposer *composer;
    gboolean html;
    const char *repl_to, *message_id, *references;
    GList *to, *cc;

    contents = camel_medium_get_content_object (CAMEL_MEDIUM (message));
    text = reply_body (contents, &html);

    composer = E_MSG_COMPOSER (e_msg_composer_new ());

    /* Set the quoted reply text. */
    if (text) {
        char *repl_text;

        if (html) {
            repl_text = g_strdup_printf ("<blockquote><i>\n%s\n"
                             "</i></blockquote>\n",
                             text);
        } else {
            char *s, *d, *quoted_text;
            int lines, len;

            /* Count the number of lines in the body. If
             * the text ends with a \n, this will be one
             * too high, but that's ok. Allocate enough
             * space for the text and the "> "s.
             */
            for (s = text, lines = 0; s; s = strchr (s + 1, '\n'))
                lines++;
            quoted_text = g_malloc (strlen (text) + lines * 2);

            s = text;
            d = quoted_text;

            /* Copy text to quoted_text line by line,
             * prepending "> ".
             */
            while (1) {
                len = strcspn (s, "\n");
                if (len == 0 && !*s)
                    break;
                sprintf (d, "> %.*s\n", len, s);
                s += len;
                if (!*s++)
                    break;
                d += len + 3;
            }

            /* Now convert that to HTML. */
            repl_text = e_text_to_html (quoted_text,
                            E_TEXT_TO_HTML_PRE);
            g_free (quoted_text);
        }
        e_msg_composer_set_body_text (composer, repl_text);
        g_free (repl_text);
        g_free (text);
    }

    /* Set the recipients */
    repl_to = camel_mime_message_get_reply_to (message);
    if (!repl_to)
        repl_to = camel_mime_message_get_from (message);
    to = g_list_append (NULL, (gpointer)repl_to);

    if (to_all) {
        const CamelInternetAddress *recip;
        const char *name, *addr;
        char *fulladdr;
        int i;

        recip = camel_mime_message_get_recipients (message, 
            CAMEL_RECIPIENT_TYPE_TO);
        i = 0;
        cc = NULL;
        while (camel_internet_address_get (recip, i++, &name, &addr)) {
            fulladdr = g_strdup_printf ("%s <%s>", name, addr);
            cc = g_list_append (cc, fulladdr);
        }

        recip = camel_mime_message_get_recipients (message,
            CAMEL_RECIPIENT_TYPE_CC);
        i = 0;
        while (camel_internet_address_get (recip, i++, &name, &addr)) {
            fulladdr = g_strdup_printf ("%s <%s>", name, addr);
            cc = g_list_append (cc, fulladdr);
        }
    } else
        cc = NULL;

    /* Set the subject of the new message. */
    subject = (char *)camel_mime_message_get_subject (message);
    if (!subject)
        subject = g_strdup ("");
    else if (!strncasecmp (subject, "Re: ", 4))
        subject = g_strdup (subject);
    else
        subject = g_strdup_printf ("Re: %s", subject);

    e_msg_composer_set_headers (composer, to, cc, NULL, subject);
    g_list_free (to);
    g_list_free (cc);
    g_free (subject);

    /* Add In-Reply-To and References. */
    message_id = camel_medium_get_header (CAMEL_MEDIUM (message),
                          "Message-Id");
    references = camel_medium_get_header (CAMEL_MEDIUM (message),
                          "References");
    if (message_id) {
        e_msg_composer_add_header (composer, "In-Reply-To",
                       message_id);
        if (references) {
            char *reply_refs;
            reply_refs = g_strdup_printf ("%s %s", references,
                              message_id);
            e_msg_composer_add_header (composer, "References",
                           reply_refs);
            g_free (reply_refs);
        }
    } else if (references)
        e_msg_composer_add_header (composer, "References", references);

    return composer;
}

/* This is part of the temporary kludge below. */
#ifndef HAVE_MKSTEMP
#include <fcntl.h>
#include <sys/stat.h>
#endif

EMsgComposer *
mail_generate_forward (CamelMimeMessage *mime_message,
               gboolean forward_as_attachment,
               gboolean keep_attachments)
{
    EMsgComposer *composer;
    char *tmpfile;
    int fd;
    CamelStream *stream;

    if (!forward_as_attachment)
        g_warning ("Forward as non-attachment not implemented.");
    if (!keep_attachments)
        g_warning ("Forwarding without attachments not implemented.");

    /* For now, we kludge by writing out a temp file. Later,
     * EMsgComposer will support attaching CamelMimeParts directly,
     * or something. FIXME.
     */
    tmpfile = g_strdup ("/tmp/evolution-kludge-XXXX");
#ifdef HAVE_MKSTEMP
    fd = mkstemp (tmpfile);
#else
    if (mktemp (tmpfile)) {
        fd = open (tmpfile, O_RDWR | O_CREAT | O_EXCL,
               S_IRUSR | S_IWUSR);
    } else
        fd = -1;
#endif
    if (fd == -1) {
        g_warning ("Couldn't create temp file for forwarding");
        g_free (tmpfile);
        return NULL;
    }

    stream = camel_stream_fs_new_with_fd (fd);
    camel_data_wrapper_write_to_stream (CAMEL_DATA_WRAPPER (mime_message),
                        stream);
    camel_stream_close (stream);

    composer = E_MSG_COMPOSER (e_msg_composer_new ());
    e_msg_composer_attachment_bar_attach (E_MSG_COMPOSER_ATTACHMENT_BAR (composer->attachment_bar), tmpfile);
    g_free (tmpfile);

    /* FIXME: should we default a subject? */

    return composer;
}