path: root/mail/mail-format.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
 * Authors: Dan Winship <danw@ximian.com>
 *          Jeffrey Stedfast <fejj@ximian.com>
 *
 *  Copyright 2000, 2003 Ximian, Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * 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.
 *
 */


#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

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

#include <gconf/gconf.h>
#include <gconf/gconf-client.h>

#include <libgnome/gnome-util.h>
#include <libgnomevfs/gnome-vfs-mime-handlers.h>
#include <shell/e-setup.h>

#include <gal/util/e-iconv.h>

#include <camel/camel-mime-utils.h>
#include <camel/camel-pgp-mime.h>
#include <camel/camel-stream-null.h>
#include <camel/camel-stream-filter.h>
#include <camel/camel-multipart-signed.h>
#include <camel/camel-mime-filter-enriched.h>
#include <camel/camel-mime-filter-tohtml.h>

#include <e-util/e-trie.h>

#include "mail.h"
#include "mail-tools.h"
#include "mail-display.h"
#include "mail-format.h"
#include "mail-mt.h"
#include "mail-crypto.h"


#define STANDARD_ISSUE_TABLE_OPEN "<table cellspacing=0 cellpadding=10 width=\"100%\">"


static gboolean handle_text_plain            (CamelMimePart *part, const char *mime_type,
                          MailDisplay *md, MailDisplayStream *stream);
static gboolean handle_text_enriched         (CamelMimePart *part, const char *mime_type,
                          MailDisplay *md, MailDisplayStream *stream);
static gboolean handle_text_html             (CamelMimePart *part, const char *mime_type,
                          MailDisplay *md, MailDisplayStream *stream);
static gboolean handle_image                 (CamelMimePart *part, const char *mime_type,
                          MailDisplay *md, MailDisplayStream *stream);
static gboolean handle_multipart_mixed       (CamelMimePart *part, const char *mime_type,
                          MailDisplay *md, MailDisplayStream *stream);
static gboolean handle_multipart_related     (CamelMimePart *part, const char *mime_type,
                          MailDisplay *md, MailDisplayStream *stream);
static gboolean handle_multipart_alternative (CamelMimePart *part, const char *mime_type,
                          MailDisplay *md, MailDisplayStream *stream);
static gboolean handle_multipart_appledouble (CamelMimePart *part, const char *mime_type,
                          MailDisplay *md, MailDisplayStream *stream);
static gboolean handle_multipart_encrypted   (CamelMimePart *part, const char *mime_type,
                          MailDisplay *md, MailDisplayStream *stream);
static gboolean handle_multipart_signed      (CamelMimePart *part, const char *mime_type,
                          MailDisplay *md, MailDisplayStream *stream);
static gboolean handle_message_rfc822        (CamelMimePart *part, const char *mime_type,
                          MailDisplay *md, MailDisplayStream *stream);
static gboolean handle_message_external_body (CamelMimePart *part, const char *mime_type,
                          MailDisplay *md, MailDisplayStream *stream);

static gboolean handle_via_bonobo            (CamelMimePart *part, const char *mime_type,
                          MailDisplay *md, MailDisplayStream *stream);

/* writes the header info for a mime message into an html stream */
static void write_headers (MailDisplayStream *stream, MailDisplay *md, CamelMimeMessage *message);

/* dispatch html printing via mimetype */
static gboolean format_mime_part (CamelMimePart *part, MailDisplay *md, MailDisplayStream *stream);

static void
free_url (gpointer key, gpointer value, gpointer data)
{
    g_free (key);
    if (data)
        g_byte_array_free (value, TRUE);
}

static void
free_part_urls (gpointer urls)
{
    g_hash_table_foreach (urls, free_url, NULL);
    g_hash_table_destroy (urls);
}

static void
free_data_urls (gpointer urls)
{
    g_hash_table_foreach (urls, free_url, GINT_TO_POINTER (1));
    g_hash_table_destroy (urls);
}

/**
 * mail_format_mime_message: 
 * @mime_message: the input mime message
 * @md: the MailDisplay to render into
 *
 * Writes a CamelMimeMessage out into a MailDisplay
 **/
void
mail_format_mime_message (CamelMimeMessage *mime_message, MailDisplay *md,
              MailDisplayStream *stream)
{
    GHashTable *hash;
    
    g_return_if_fail (CAMEL_IS_MIME_MESSAGE (mime_message));
    
    hash = g_datalist_get_data (md->data, "part_urls");
    if (!hash) {
        hash = g_hash_table_new (g_str_hash, g_str_equal);
        g_datalist_set_data_full (md->data, "part_urls", hash,
                      free_part_urls);
    }
    hash = g_datalist_get_data (md->data, "data_urls");
    if (!hash) {
        hash = g_hash_table_new (g_str_hash, g_str_equal);
        g_datalist_set_data_full (md->data, "data_urls", hash,
                      free_data_urls);
    }
    
    hash = g_datalist_get_data (md->data, "attachment_states");
    if (!hash) {
        hash = g_hash_table_new (NULL, NULL);
        g_datalist_set_data_full (md->data, "attachment_states", hash,
                      (GDestroyNotify) g_hash_table_destroy);
    }
    hash = g_datalist_get_data (md->data, "fake_parts");
    if (!hash) {
        hash = g_hash_table_new (NULL, NULL);
        g_datalist_set_data_full (md->data, "fake_parts", hash,
                      (GDestroyNotify) g_hash_table_destroy);
    }
    
    write_headers (stream, md, mime_message);
    format_mime_part (CAMEL_MIME_PART (mime_message), md, stream);
}


/**
 * mail_format_raw_message: 
 * @mime_message: the input mime message
 * @md: the MailDisplay to render into
 *
 * Writes a CamelMimeMessage source out into a MailDisplay
 **/
void
mail_format_raw_message (CamelMimeMessage *mime_message, MailDisplay *md,
             MailDisplayStream *stream)
{
    CamelStreamFilter *filtered_stream;
    CamelMimeFilter *html_filter;
    CamelDataWrapper *wrapper;
    guint32 flags;
    
    g_return_if_fail (CAMEL_IS_MIME_MESSAGE (mime_message));
    
    wrapper = CAMEL_DATA_WRAPPER (mime_message);
    if (!mail_content_loaded (wrapper, md, TRUE, NULL, md->html, NULL))
        return;
    
    filtered_stream = camel_stream_filter_new_with_stream ((CamelStream *) stream);
    
    flags = CAMEL_MIME_FILTER_TOHTML_CONVERT_NL | CAMEL_MIME_FILTER_TOHTML_CONVERT_SPACES |
        CAMEL_MIME_FILTER_TOHTML_ESCAPE_8BIT;
    html_filter = camel_mime_filter_tohtml_new (flags, 0);
    camel_stream_filter_add (filtered_stream, html_filter);
    camel_object_unref (html_filter);
    
    camel_stream_write_string ((CamelStream *) stream, STANDARD_ISSUE_TABLE_OPEN "<tr><td><tt>");
    
    mail_format_data_wrapper_write_to_stream (wrapper, md, (CamelStream *) filtered_stream);
    camel_object_unref (filtered_stream);
    
    camel_stream_write_string ((CamelStream *) stream, "</tt></td></tr></table>");
}

static const char *
get_cid (CamelMimePart *part, MailDisplay *md)
{
    static int fake_cid_counter = 0;
    char *cid;
    
    /* If we have a real Content-ID, use it. If we don't,
     * make a (syntactically invalid, unique) fake one.
     */
    if (camel_mime_part_get_content_id (part)) {
        cid = g_strdup_printf ("cid:%s", camel_mime_part_get_content_id (part));
    } else
        cid = g_strdup_printf ("cid:@@@%d", fake_cid_counter++);
    
    return mail_display_add_url (md, "part_urls", cid, part);
}

static const char *
get_location (CamelMimePart *part, MailDisplay *md)
{
    CamelURL *base;
    const char *loc;
    char *location;
    
    base = mail_display_get_content_location (md);
    
    loc = camel_mime_part_get_content_location (part);
    if (!loc) {
        if (!base)
            return NULL;
        
        location = camel_url_to_string (base, 0);
        return mail_display_add_url (md, "part_urls", location, part);
    }
    
    /* kludge: If the multipart/related does not have a
           Content-Location header and the HTML part doesn't contain a
           Content-Location header either, then we will end up
           generating a invalid unique identifier in the form of
           "cid:@@@%d" for use in GtkHTML's iframe src url. This means
           that when GtkHTML requests a relative URL, it will request
           "cid:/%s" */
    mail_display_add_url (md, "part_urls", g_strdup_printf ("cid:/%s", loc), part);
    
    if (!strchr (loc, ':') && base) {
        CamelURL *url;
        
        mail_display_add_url (md, "part_urls", g_strdup (loc), part);
        
        url = camel_url_new_with_base (base, loc);
        location = camel_url_to_string (url, 0);
        camel_url_free (url);
    } else {
        location = g_strdup (loc);
    }
    
    return mail_display_add_url (md, "part_urls", location, part);
}


static GHashTable *mime_handler_table, *mime_function_table;

static void
setup_mime_tables (void)
{
    mime_handler_table = g_hash_table_new (g_str_hash, g_str_equal);
    mime_function_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/gif",
                 handle_image);
    g_hash_table_insert (mime_function_table, "image/jpeg",
                 handle_image);
    g_hash_table_insert (mime_function_table, "image/png",
                 handle_image);
    g_hash_table_insert (mime_function_table, "image/x-png",
                 handle_image);
    g_hash_table_insert (mime_function_table, "image/tiff",
                 handle_image);
    g_hash_table_insert (mime_function_table, "image/x-bmp",
                 handle_image);
    g_hash_table_insert (mime_function_table, "image/bmp",
                 handle_image);
    g_hash_table_insert (mime_function_table, "image/x-cmu-raster",
                 handle_image);
    g_hash_table_insert (mime_function_table, "image/x-ico",
                 handle_image);
    g_hash_table_insert (mime_function_table, "image/x-portable-anymap",
                 handle_image);
    g_hash_table_insert (mime_function_table, "image/x-portable-bitmap",
                 handle_image);
    g_hash_table_insert (mime_function_table, "image/x-portable-graymap",
                 handle_image);
    g_hash_table_insert (mime_function_table, "image/x-portable-pixmap",
                 handle_image);
    g_hash_table_insert (mime_function_table, "image/x-xpixmap",
                 handle_image);
    
    g_hash_table_insert (mime_function_table, "message/rfc822",
                 handle_message_rfc822);
    g_hash_table_insert (mime_function_table, "message/news",
                 handle_message_rfc822);
    g_hash_table_insert (mime_function_table, "message/external-body",
                 handle_message_external_body);
    
    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);
    g_hash_table_insert (mime_function_table, "multipart/encrypted",
                 handle_multipart_encrypted);
    g_hash_table_insert (mime_function_table, "multipart/signed",
                 handle_multipart_signed);
    
    /* 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_function_table, "text/*",
                 handle_text_plain);
    g_hash_table_insert (mime_function_table, "multipart/*",
                 handle_multipart_mixed);
}

static gboolean
component_supports (Bonobo_ServerInfo *component, const char *mime_type)
{
    Bonobo_ActivationProperty *prop;
    CORBA_sequence_CORBA_string stringv;
    int i;
    
    prop = bonobo_server_info_prop_find (component, "repo_ids");
    if (!prop || prop->v._d != Bonobo_ACTIVATION_P_STRINGV)
        return FALSE;
    
    stringv = prop->v._u.value_stringv;
    for (i = 0; i < stringv._length; i++) {
        if (!strcasecmp ("IDL:Bonobo/PersistStream:1.0", stringv._buffer[i]))
            break;
    }
    
    /* got to end of list with no persist stream? */
    
    if (i >= stringv._length)
        return FALSE;
    
    prop = bonobo_server_info_prop_find (component,
                         "bonobo:supported_mime_types");
    if (!prop || prop->v._d != Bonobo_ACTIVATION_P_STRINGV)
        return FALSE;
    
    stringv = prop->v._u.value_stringv;
    for (i = 0; i < stringv._length; i++) {
        if (!strcasecmp (mime_type, stringv._buffer[i]))
            return TRUE;
    }
    
    return FALSE;
}

/**
 * mail_lookup_handler:
 * @mime_type: a MIME type
 *
 * Looks up the MIME type in its own tables and GNOME-VFS's and returns
 * a MailMimeHandler structure detailing the component, application,
 * and built-in handlers (if any) for that MIME type. (If the component
 * is non-%NULL, the built-in handler will always be handle_via_bonobo().)
 * The MailMimeHandler's @generic field is set if the match was for the
 * MIME supertype rather than the exact type.
 *
 * Return value: a MailMimeHandler (which should not be freed), or %NULL
 * if no handlers are available.
 **/
MailMimeHandler *
mail_lookup_handler (const char *mime_type)
{
    MailMimeHandler *handler;
    char *mime_type_main;
    const char *p;
    GList *components, *iter;
    
    if (mime_handler_table == NULL)
        setup_mime_tables ();
    
    /* See if we've already found it. */
    handler = g_hash_table_lookup (mime_handler_table, mime_type);
    if (handler)
        return handler;
    
    /* Special case MIME type: application/octet-stream
     * The point of this type is that there isn't a handler. 
     */
    if (strcmp (mime_type, "application/octet-stream") == 0)
        return NULL;
    
    /* No. Create a new one and look up application and full type
     * handler. If we find a builtin, create the handler and
     * register it.
     */
    handler = g_new0 (MailMimeHandler, 1);
    handler->applications =
        gnome_vfs_mime_get_short_list_applications (mime_type);
    handler->builtin =
        g_hash_table_lookup (mime_function_table, mime_type);
    
    if (handler->builtin) {
        handler->generic = FALSE;
        handler->is_bonobo = FALSE;
        goto reg;
    }
    
    /* Try for the first matching component. (we don't use get_short_list_comps
     * as that will return NULL if the oaf files don't have the short_list properties
     * defined). */
    components = gnome_vfs_mime_get_all_components (mime_type);
    for (iter = components; iter; iter = iter->next) {
        if (component_supports (iter->data, mime_type)) {
            handler->generic = FALSE;
            handler->is_bonobo = TRUE;
            handler->builtin = handle_via_bonobo;
            handler->component = Bonobo_ServerInfo_duplicate (iter->data);
            gnome_vfs_mime_component_list_free (components);
            goto reg;
        }
    }
    
    gnome_vfs_mime_component_list_free (components);
    
    /* Try for a generic builtin match. */
    p = strchr (mime_type, '/');
    if (p == NULL)
        p = mime_type + strlen (mime_type);
    mime_type_main = g_alloca ((p - mime_type) + 3);
    memcpy (mime_type_main, mime_type, p - mime_type);
    memcpy (mime_type_main + (p - mime_type), "/*", 3);
    
    handler->builtin = g_hash_table_lookup (mime_function_table,
                        mime_type_main);
    
    if (handler->builtin) {
        handler->generic = TRUE;
        handler->is_bonobo = FALSE;
        if (handler->component) {
            CORBA_free (handler->component);
            handler->component = NULL;
        }
        goto reg;
    }
    
    /* Try for a generic component match. */
    if (handler->component) {
        handler->generic = TRUE;
        handler->is_bonobo = TRUE;
        handler->builtin = handle_via_bonobo;
        goto reg;
    }
    
    /* If we at least got an application, use that. */
    if (handler->applications) {
        handler->generic = TRUE;
        handler->is_bonobo = FALSE;
        goto reg;
    }
    
    /* Nada. */
    g_free (handler);
    return NULL;
    
 reg:
    g_hash_table_insert (mime_handler_table, g_strdup (mime_type), handler);
    
    return handler;
}

/* An "anonymous" MIME part is one that we shouldn't call attention
 * to the existence of, but simply display.
 */
static gboolean
is_anonymous (CamelMimePart *part, const char *mime_type)
{
    /* FIXME: should use CamelContentType stuff */
    if (!strncasecmp (mime_type, "multipart/", 10) ||
        !strncasecmp (mime_type, "message/", 8))
        return TRUE;
    
    if (!strncasecmp (mime_type, "text/", 5) &&
        !camel_mime_part_get_filename (part))
        return TRUE;
    
    return FALSE;
}

/**
 * mail_part_is_inline:
 * @part: a CamelMimePart
 *
 * Return value: whether or not the part should/will be displayed inline.
 **/
gboolean
mail_part_is_inline (CamelMimePart *part)
{
    const char *disposition;
    CamelContentType *content_type;
    gboolean anon;
    char *type;
    
    /* If it has an explicit disposition, return that. */
    disposition = camel_mime_part_get_disposition (part);
    if (disposition)
        return strcasecmp (disposition, "inline") == 0;
    
    /* Certain types should default to inline. FIXME: this should
     * be customizable.
     */
    content_type = camel_mime_part_get_content_type (part);
    if (!header_content_type_is (content_type, "message", "*"))
        return TRUE;
    
    /* Otherwise, display it inline if it's "anonymous", and
     * as an attachment otherwise.
     */
    type = header_content_type_simple (content_type);
    anon = is_anonymous (part, type);
    g_free (type);
    
    return anon;
}

enum inline_states {
    I_VALID     = (1 << 0),
    I_ACTUALLY  = (1 << 1),
    I_DISPLAYED = (1 << 2)
};

static int
get_inline_flags (CamelMimePart *part, MailDisplay *md)
{
    GHashTable *asht;
    int val;
    
    /* check if we already know. */
    
    asht = g_datalist_get_data (md->data, "attachment_states");
    val = GPOINTER_TO_INT (g_hash_table_lookup (asht, part));
    if (val)
        return val;
    
    /* ok, we don't know. Figure it out. */
    
    if (mail_part_is_inline (part))
        val = (I_VALID | I_ACTUALLY | I_DISPLAYED);
    else
        val = (I_VALID);
    
    g_hash_table_insert (asht, part, GINT_TO_POINTER (val));
    
    return val;
}

gboolean
mail_part_is_displayed_inline (CamelMimePart *part, MailDisplay *md)
{
    return (gboolean) (get_inline_flags (part, md) & I_DISPLAYED);
}

void
mail_part_toggle_displayed (CamelMimePart *part, MailDisplay *md)
{
    GHashTable *asht = g_datalist_get_data (md->data, "attachment_states");
    gpointer ostate, opart;
    int state;
    
    if (g_hash_table_lookup_extended (asht, part, &opart, &ostate)) {
        g_hash_table_remove (asht, part);
        
        state = GPOINTER_TO_INT (ostate);
        
        if (state & I_DISPLAYED)
            state &= ~I_DISPLAYED;
        else
            state |= I_DISPLAYED;
    } else {
        state = I_VALID | I_DISPLAYED;
    }
    
    g_hash_table_insert (asht, part, GINT_TO_POINTER (state));
}

static void
mail_part_set_default_displayed_inline (CamelMimePart *part, MailDisplay *md,
                    gboolean displayed)
{
    GHashTable *asht = g_datalist_get_data (md->data, "attachment_states");
    int state;
    
    if (g_hash_table_lookup (asht, part))
        return;
    
    state = I_VALID | (displayed ? I_DISPLAYED : 0);
    g_hash_table_insert (asht, part, GINT_TO_POINTER (state));
}

static void
attachment_header (CamelMimePart *part, const char *mime_type, MailDisplay *md,
           MailDisplayStream *stream)
{
    char *htmlinfo;
    const char *info;
    
    /* Start the table, create the pop-up object. */
    camel_stream_write_string ((CamelStream *) stream, "<table cellspacing=0 cellpadding=0><tr><td>"
                   "<table width=10 cellspacing=0 cellpadding=0>"
                   "<tr><td></td></tr></table></td>");
    
    if (!md->printing) {
        camel_stream_printf ((CamelStream *) stream, "<td><object classid=\"popup:%s\""
                     "type=\"%s\"></object></td>", get_cid (part, md), mime_type);
    }
    
    camel_stream_write_string ((CamelStream *) stream, "<td><table width=3 cellspacing=0 cellpadding=0>"
                  "<tr><td></td></tr></table></td><td><font size=-1>");
    
    /* Write the MIME type */
    info = gnome_vfs_mime_get_description (mime_type);
    htmlinfo = camel_text_to_html (info ? info : mime_type, 0, 0);
    camel_stream_printf ((CamelStream *) stream, _("%s attachment"), htmlinfo);
    g_free (htmlinfo);
    
    /* Write the name, if we have it. */
    info = camel_mime_part_get_filename (part);
    if (info) {
        htmlinfo = camel_text_to_html (info, 0, 0);
        camel_stream_printf ((CamelStream *) stream, " (%s)", htmlinfo);
        g_free (htmlinfo);
    }
    
    /* Write a description, if we have one. */
    info = camel_mime_part_get_description (part);
    if (info) {
        htmlinfo = camel_text_to_html (info, md->printing ? 0 : CAMEL_MIME_FILTER_TOHTML_CONVERT_URLS, 0);
        camel_stream_printf ((CamelStream *) stream, ", \"%s\"", htmlinfo);
        g_free (htmlinfo);
    }
    
    camel_stream_write_string ((CamelStream *) stream, "</font></td></tr><tr><td height=10>"
                   "<table cellspacing=0 cellpadding=0><tr><td height=10>"
                   "<a name=\"glue\"></td></tr></table></td></tr></table>\n");
}

static gboolean
format_mime_part (CamelMimePart *part, MailDisplay *md,
          MailDisplayStream *stream)
{
    CamelDataWrapper *wrapper;
    MailMimeHandler *handler;
    gboolean output;
    int inline_flags;
    char *mime_type;
    
    /* Record URLs associated with this part */
    get_cid (part, md);
    get_location (part, md);
    
    wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (part));
    
    if (CAMEL_IS_MULTIPART (wrapper) &&
        camel_multipart_get_number (CAMEL_MULTIPART (wrapper)) == 0) {
        mail_error_printf (stream, "\n%s\n", _("Could not parse MIME message. Displaying as source."));
        if (mail_content_loaded (wrapper, md, TRUE, NULL, md->html, NULL))
            handle_text_plain (part, "text/plain", md, stream);
        return TRUE;
    }
    
    mime_type = camel_data_wrapper_get_mime_type (wrapper);
    camel_strdown (mime_type);
    
    handler = mail_lookup_handler (mime_type);
    if (!handler) {
        char *id_type;
        
        /* Special case MIME types that we know that we can't
         * display but are some kind of plain text to prevent
         * evil infinite recursion.
         */
        
        if (!strcmp (mime_type, "application/mac-binhex40")) {
            handler = NULL;
        } else {
            id_type = mail_identify_mime_part (part, md);
            if (id_type) {
                g_free (mime_type);
                mime_type = id_type;
                handler = mail_lookup_handler (id_type);
            }
        }
    }
    
    inline_flags = get_inline_flags (part, md);
    
    /* No header for anonymous inline parts. */
    if (!((inline_flags & I_ACTUALLY) && is_anonymous (part, mime_type)))
        attachment_header (part, mime_type, md, stream);
    
    if (handler && handler->builtin && inline_flags & I_DISPLAYED &&
        mail_content_loaded (wrapper, md, TRUE, NULL, md->html, NULL))
        output = (*handler->builtin) (part, mime_type, md, stream);
    else
        output = TRUE;
    
    g_free (mime_type);
    return output;
}

/* flags for write_field_to_stream */
enum {
    WRITE_BOLD=1,
    WRITE_NOCOLUMNS=2,
};

static void
write_field_row_begin (MailDisplayStream *stream, const char *name, int flags)
{
    gboolean bold = (flags & WRITE_BOLD);
    gboolean nocolumns = (flags & WRITE_NOCOLUMNS);
    
    if (nocolumns) {
        camel_stream_printf ((CamelStream *) stream, "<tr><td>%s%s:%s ",
                     bold ? "<b>" : "", name, bold ? "</b>" : "");
    } else {
        camel_stream_printf ((CamelStream *) stream,
                     "<tr><%s align=\"right\" valign=\"top\">%s:"
                     "<b>&nbsp;</%s><td>", bold ? "th" : "td",
                     name, bold ? "th" : "td");
    }
}

static void
write_date (MailDisplayStream *stream, CamelMimeMessage *message, int flags)
{
    const char *datestr;
    
    datestr = camel_medium_get_header (CAMEL_MEDIUM (message), "Date");
    
    if (datestr) {
        write_field_row_begin (stream, _("Date"), flags);
        camel_stream_printf ((CamelStream *) stream, "%s</td> </tr>", datestr);
    }
}

static void
write_text_header (MailDisplayStream *stream, const char *name, const char *value, int flags)
{
    char *encoded;
    
    if (value && *value)
        encoded = camel_text_to_html (value, CAMEL_MIME_FILTER_TOHTML_CONVERT_NL |
                          CAMEL_MIME_FILTER_TOHTML_CONVERT_SPACES |
                          CAMEL_MIME_FILTER_TOHTML_CONVERT_URLS, 0);
    else
        encoded = "";
    
    write_field_row_begin (stream, name, flags);
    
    camel_stream_printf ((CamelStream *) stream, "%s</td></tr>", encoded);
    
    if (value && *value)
        g_free (encoded);
}

static void
write_address (MailDisplay *md, MailDisplayStream *stream,
           const CamelInternetAddress *addr, const char *field_name, int flags)
{
    const char *name, *email;
    int i;
    
    if (addr == NULL || !camel_internet_address_get (addr, 0, NULL, NULL))
        return;
    
    write_field_row_begin (stream, field_name, flags);
    
    i = 0;
    while (camel_internet_address_get (addr, i, &name, &email)) {
        CamelInternetAddress *subaddr;
        char *addr_txt, *addr_url;
        gboolean have_name = name && *name;
        gboolean have_email = email && *email;
        char *name_disp = NULL;
        char *email_disp = NULL;
        
        subaddr = camel_internet_address_new ();
        camel_internet_address_add (subaddr, name, email);
        addr_txt = camel_address_format (CAMEL_ADDRESS (subaddr));
        addr_url = camel_url_encode (addr_txt, TRUE, NULL);
        camel_object_unref (subaddr);
        
        if (have_name) {
            name_disp = camel_text_to_html (name, 0, 0);
        }
        
        if (have_email) {
            email_disp = camel_text_to_html (email, 0, 0);
        }
        
        if (i)
            camel_stream_write_string ((CamelStream *) stream, ", ");
        
        if (have_email || have_name) {
            if (!have_email)
                email_disp = g_strdup ("???");
            
            if (have_name) {
                if (md->printing) {
                    camel_stream_printf ((CamelStream *) stream,
                                 "%s &lt;%s&gt;", name_disp, email_disp);
                } else {
                    camel_stream_printf ((CamelStream *) stream,
                                 "%s &lt;<a href=\"mailto:%s\">%s</a>&gt;",
                                 name_disp, addr_url, email_disp);
                }
            } else {
                if (md->printing) {
                    camel_stream_write_string ((CamelStream *) stream, email_disp);
                } else {
                    camel_stream_printf ((CamelStream *) stream,
                                 "<a href=\"mailto:%s\">%s</a>",
                                 addr_url, email_disp);
                }
            }
        } else {
            camel_stream_printf ((CamelStream *) stream, "<i>%s</i>", _("Bad Address"));
        }
        
        g_free (name_disp);
        g_free (email_disp);
        g_free (addr_txt);
        g_free (addr_url);
        
        i++;
    }
    
    camel_stream_write_string ((CamelStream *) stream, "</td></tr>");
}

/* order of these must match write_header code */
static char *default_headers[] = {
    "From", "Reply-To", "To", "Cc", "Bcc", "Subject", "Date",
};

/* return index of header in default_headers array */
static int
default_header_index (const char *name)
{
    int i;
    
    for (i = 0; i < sizeof (default_headers) / sizeof (default_headers[0]); i++)
        if (!strcasecmp (name, default_headers[i]))
            return i;
    
    return -1;
}

/* index is index of header in default_headers array */
static void
write_default_header (CamelMimeMessage *message, MailDisplay *md, 
              MailDisplayStream *stream,
              int index, int flags)
{
    switch (index) {
    case 0:
        write_address (md, stream,
                   camel_mime_message_get_from (message), _("From"), flags | WRITE_BOLD);
        break;
    case 1:
        write_address (md, stream, 
                   camel_mime_message_get_reply_to (message), _("Reply-To"), flags | WRITE_BOLD);
        break;
    case 2:
        write_address (md, stream,
                   camel_mime_message_get_recipients (message, CAMEL_RECIPIENT_TYPE_TO),
                  _("To"), flags | WRITE_BOLD);
        break;
    case 3:
        write_address (md, stream,
                   camel_mime_message_get_recipients (message, CAMEL_RECIPIENT_TYPE_CC),
                   _("Cc"), flags | WRITE_BOLD);
        break;
    case 4:
        write_address (md, stream,
                   camel_mime_message_get_recipients (message, CAMEL_RECIPIENT_TYPE_BCC),
                   _("Bcc"), flags | WRITE_BOLD);
        break;
    case 5:
        write_text_header (stream, _("Subject"), camel_mime_message_get_subject (message),
                   flags | WRITE_BOLD);
        break;
    case 6:
        write_date (stream, message, flags | WRITE_BOLD);
        break;
    default:
        g_assert_not_reached ();
    }
}

static gboolean
write_xmailer_header (CamelMimeMessage *message, MailDisplay *md,
              MailDisplayStream *stream, int xmask)
{
    const char *xmailer, *evolution;
    
    xmailer = camel_medium_get_header (CAMEL_MEDIUM (message), "X-Mailer");
    if (!xmailer) {
        xmailer = camel_medium_get_header (CAMEL_MEDIUM (message), "User-Agent");
        if (!xmailer)
            return FALSE;
    }
    
    evolution = strstr (xmailer, "Evolution");
    if ((xmask & MAIL_CONFIG_XMAILER_OTHER) ||
        (evolution && (xmask & MAIL_CONFIG_XMAILER_EVO)))
        write_text_header (stream, _("Mailer"), xmailer, WRITE_BOLD);
    
    return evolution != NULL && (xmask & MAIL_CONFIG_XMAILER_RUPERT_APPROVED);
}

#define COLOR_IS_LIGHT(r, g, b)  ((r + g + b) > (128 * 3))

static void
write_headers (MailDisplayStream *stream, MailDisplay *md, CamelMimeMessage *message)
{
    gboolean full = (md->display_style == MAIL_CONFIG_DISPLAY_FULL_HEADERS);
    char bgcolor[7], fontcolor[7];
    GtkStyle *style = NULL;
    gboolean evo_icon = FALSE;
    GConfClient *gconf;
    int xmask, i;
    
    gconf = gconf_client_get_default ();
    xmask = gconf_client_get_int (gconf, "/apps/evolution/mail/display/xmailer_mask", NULL);
    
    /* My favorite thing to do... muck around with colors so we respect people's stupid themes.
       However, we only do this if we are rendering to the screen -- we ignore the theme
       when we are printing. */
    style = gtk_widget_get_style (GTK_WIDGET (md->html));
    if (style && !md->printing) {
        int state = GTK_WIDGET_STATE (GTK_WIDGET (md->html));
        gushort r, g, b;
        
        r = style->base[state].red / 256;
        g = style->base[state].green / 256;
        b = style->base[state].blue / 256;
        
        if (COLOR_IS_LIGHT (r, g, b)) {
            r *= 0.92;
            g *= 0.92;
            b *= 0.92;
        } else {
            r = 255 - (0.92 * (255 - r));
            g = 255 - (0.92 * (255 - g));
            b = 255 - (0.92 * (255 - b));
        }
        
        sprintf (bgcolor, "%.2X%.2X%.2X", r, g, b);
        
        r = style->text[state].red / 256;
        g = style->text[state].green / 256;
        b = style->text[state].blue / 256;
        
        sprintf (fontcolor, "%.2X%.2X%.2X", r, g, b);
    } else {
        strcpy (bgcolor, "EEEEEE");
        strcpy (fontcolor, "000000");
    }
    
    camel_stream_write_string ((CamelStream *) stream,
                   "<table width=\"100%\" cellpadding=0 cellspacing=0>");
    
    /* Top margin */
    camel_stream_write_string ((CamelStream *) stream, "<tr><td colspan=3 height=10>"
                   "<table cellpadding=0 cellspacing=0><tr><td height=10>"
                   "<a name=\"glue\"></td></tr></table></td></tr>");
    
    /* Left margin */
    camel_stream_write_string ((CamelStream *) stream, "<tr><td><table width=10 "
                   "cellpadding=0 cellspacing=0><tr><td></td></tr></table></td>");
    
    /* Black border */
    camel_stream_write_string ((CamelStream *) stream, "<td width=\"100%\"><table bgcolor=\"#000000\" "
                   "width=\"100%\" cellspacing=0 cellpadding=1>");
    
    /* Main header box */
    camel_stream_printf ((CamelStream *) stream, "<tr><td><table bgcolor=\"#%s\" width=\"100%%\" "
                 "cellpadding=0 cellspacing=0>"
                 /* Internal header table */
                 "<tr valign=top><td><table><font color=\"#%s\">\n",
                 bgcolor, fontcolor);
    
    if (full) {
        struct _header_raw *header;
        const char *charset;
        CamelContentType *ct;
        char *value;
        
        ct = camel_mime_part_get_content_type (CAMEL_MIME_PART (message));
        charset = header_content_type_param (ct, "charset");
        charset = e_iconv_charset_name (charset);
        
        header = CAMEL_MIME_PART (message)->headers;
        while (header) {
            i = default_header_index (header->name);
            if (i == -1) {
                value = header_decode_string (header->value, charset);
                write_text_header (stream, header->name, value, WRITE_NOCOLUMNS);
                g_free (value);
            } else
                write_default_header (message, md, stream, i, WRITE_NOCOLUMNS);
            header = header->next;
        }
    } else {
        for (i = 0; i < sizeof (default_headers) / sizeof (default_headers[0]); i++)
            write_default_header (message, md, stream, i, 0);
        if (xmask != MAIL_CONFIG_XMAILER_NONE)
            evo_icon = write_xmailer_header (message, md, stream, xmask);
    }
    
    /* Close off the internal header table */
    camel_stream_write_string ((CamelStream *) stream, "</font></table></td>");
    
    if (!md->printing && evo_icon) {
        camel_stream_printf ((CamelStream *) stream, "<td align=right><table><tr><td width=16>"
                     "<img src=\"%s\"></td></tr></table></td>",
                     mail_display_get_url_for_icon (md, EVOLUTION_ICONSDIR "/monkey-16.png"));
    }
    
    camel_stream_write_string ((CamelStream *) stream,
                   /* Main header box */
                   "</tr></table>"
                   /* Black border */
                   "</td></tr></table></td>"
                   /* Right margin */
                   "<td><table width=10 cellpadding=0 cellspacing=0>"
                   "<tr><td></td></tr></table></td>"
                   "</tr></table>\n");
}

static void
load_offline_content (MailDisplay *md, gpointer data)
{
    CamelDataWrapper *wrapper = data;
    CamelStream *stream;
    
    stream = camel_stream_null_new ();
    camel_data_wrapper_write_to_stream (wrapper, stream);
    camel_object_unref (stream);
    camel_object_unref (wrapper);
}

gboolean
mail_content_loaded (CamelDataWrapper *wrapper, MailDisplay *md, gboolean redisplay, const char *url,
             GtkHTML *html, GtkHTMLStream *stream)
{
    if (!camel_data_wrapper_is_offline (wrapper))
        return TRUE;
    
    camel_object_ref (wrapper);
    if (redisplay) {
        mail_display_redisplay_when_loaded (md, wrapper, load_offline_content,
                            html, wrapper);
    } else {
        mail_display_stream_write_when_loaded (md, wrapper, url, load_offline_content,
                               html, stream, wrapper);
    }
    
    return FALSE;
}


ssize_t
mail_format_data_wrapper_write_to_stream (CamelDataWrapper *wrapper, MailDisplay *mail_display, CamelStream *stream)
{
    CamelStreamFilter *filtered_stream;
    ssize_t written;
    
    filtered_stream = camel_stream_filter_new_with_stream (stream);
    
    if (wrapper->rawtext || (mail_display && mail_display->charset)) {
        CamelMimeFilterCharset *filter;
        GConfClient *gconf;
        char *charset;
        
        gconf = gconf_client_get_default ();
        
        if (!wrapper->rawtext) {
            /* data wrapper had been successfully converted to UTF-8 using the mime
               part's charset, but the user thinks he knows best so we'll let him
               shoot himself in the foot here... */
            CamelContentType *content_type;
            
            /* get the original charset of the mime part */
            content_type = camel_data_wrapper_get_mime_type_field (wrapper);
            charset = (char *) (content_type ? header_content_type_param (content_type, "charset") : NULL);
            if (!charset)
                charset = gconf_client_get_string (gconf, "/apps/evolution/mail/format/charset", NULL);
            else
                charset = g_strdup (charset);
            
            /* since the content is already in UTF-8, we need to decode into the
               original charset before we can convert back to UTF-8 using the charset
               the user is overriding with... */
            if ((filter = camel_mime_filter_charset_new_convert ("utf-8", charset))) {
                camel_stream_filter_add (filtered_stream, CAMEL_MIME_FILTER (filter));
                camel_object_unref (filter);
            }
            
            g_free (charset);
        }
        
        /* find out the charset the user wants to override to */
        if (mail_display && mail_display->charset)
            charset = g_strdup (mail_display->charset);
        else
            charset = gconf_client_get_string (gconf, "/apps/evolution/mail/format/charset", NULL);
        
        if ((filter = camel_mime_filter_charset_new_convert (charset, "utf-8"))) {
            camel_stream_filter_add (filtered_stream, CAMEL_MIME_FILTER (filter));
            camel_object_unref (filter);
        }
        
        g_free (charset);
    }
    
    written = camel_data_wrapper_write_to_stream (wrapper, CAMEL_STREAM (filtered_stream));
    camel_stream_flush (CAMEL_STREAM (filtered_stream));
    camel_object_unref (filtered_stream);
    
    return written;
}

/* Return the contents of a data wrapper, or %NULL if it contains only
 * whitespace.
 */
GByteArray *
mail_format_get_data_wrapper_text (CamelDataWrapper *wrapper, MailDisplay *mail_display)
{
    CamelStream *memstream;
    GByteArray *ba;
    char *text, *end;
    
    memstream = camel_stream_mem_new ();
    ba = g_byte_array_new ();
    camel_stream_mem_set_byte_array (CAMEL_STREAM_MEM (memstream), ba);
    
    mail_format_data_wrapper_write_to_stream (wrapper, mail_display, memstream);
    camel_object_unref (memstream);
    
    for (text = ba->data, end = text + ba->len; text < end; text++) {
        if (!isspace ((unsigned char) *text))
            break;
    }
    
    if (text >= end) {
        g_byte_array_free (ba, TRUE);
        return NULL;
    }
    
    return ba;
}

static void
write_hr (MailDisplayStream *stream)
{
    camel_stream_write_string ((CamelStream *) stream, STANDARD_ISSUE_TABLE_OPEN
                   "<tr><td width=\"100%\"><hr noshadow size=1>"
                   "</td></tr></table>\n");
}

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

static gboolean
handle_text_plain (CamelMimePart *part, const char *mime_type,
           MailDisplay *md, MailDisplayStream *stream)
{
    CamelStreamFilter *filtered_stream;
    CamelMimeFilter *html_filter;
    CamelDataWrapper *wrapper;
    CamelContentType *type;
    const char *format;
    GConfClient *gconf;
    guint32 flags, rgb = 0;
    GdkColor colour;
    char *buf;
    
    gconf = gconf_client_get_default ();
    
    flags = CAMEL_MIME_FILTER_TOHTML_CONVERT_NL | CAMEL_MIME_FILTER_TOHTML_CONVERT_SPACES;
    if (!md->printing) {
        flags |= CAMEL_MIME_FILTER_TOHTML_CONVERT_URLS | CAMEL_MIME_FILTER_TOHTML_CONVERT_ADDRESSES;
        if (gconf_client_get_bool (gconf, "/apps/evolution/mail/display/mark_citations", NULL)) {
            flags |= CAMEL_MIME_FILTER_TOHTML_MARK_CITATION;
            
            buf = gconf_client_get_string (gconf, "/apps/evolution/mail/display/citation_colour", NULL);
            gdk_color_parse (buf ? buf : "#737373", &colour);
            g_free (buf);
            
            rgb = ((colour.red & 0xff00) << 8) | (colour.green & 0xff00) | ((colour.blue & 0xff00) >> 8);
        }
    }
    
    /* Check for RFC 2646 flowed text. */
    type = camel_mime_part_get_content_type (part);
    format = header_content_type_param (type, "format");
    if (format && !strcasecmp (format, "flowed"))
        flags |= CAMEL_MIME_FILTER_TOHTML_FORMAT_FLOWED;
    
    html_filter = camel_mime_filter_tohtml_new (flags, rgb);
    filtered_stream = camel_stream_filter_new_with_stream ((CamelStream *) stream);
    camel_stream_filter_add (filtered_stream, html_filter);
    camel_object_unref (html_filter);
    
    camel_stream_write_string ((CamelStream *) stream, STANDARD_ISSUE_TABLE_OPEN "<tr><td><tt>\n");
    
    wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (part));
    mail_format_data_wrapper_write_to_stream (wrapper, md, (CamelStream *) filtered_stream);
    
    camel_stream_write_string ((CamelStream *) stream, "</tt></td></tr></table>\n");
    
    camel_object_unref (filtered_stream);
    
    return TRUE;
}

/* text/enriched (RFC 1896) or text/richtext (included in RFC 1341) */
static gboolean
handle_text_enriched (CamelMimePart *part, const char *mime_type,
              MailDisplay *md, MailDisplayStream *stream)
{
    CamelStreamFilter *filtered_stream;
    CamelMimeFilter *enriched;
    CamelDataWrapper *wrapper;
    guint32 flags = 0;
    
    wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (part));
    
    if (!strcasecmp (mime_type, "text/richtext")) {
        flags = CAMEL_MIME_FILTER_ENRICHED_IS_RICHTEXT;
        camel_stream_write_string ((CamelStream *) stream, "\n<!-- text/richtext -->\n");
    } else {
        camel_stream_write_string ((CamelStream *) stream, "\n<!-- text/enriched -->\n");
    }
    
    enriched = camel_mime_filter_enriched_new (flags);
    filtered_stream = camel_stream_filter_new_with_stream ((CamelStream *) stream);
    camel_stream_filter_add (filtered_stream, enriched);
    camel_object_unref (enriched);
    
    camel_stream_write_string ((CamelStream *) stream, STANDARD_ISSUE_TABLE_OPEN "<tr><td><tt>\n"); 
    wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (part));
    mail_format_data_wrapper_write_to_stream (wrapper, md, (CamelStream *) filtered_stream);
    
    camel_stream_write_string ((CamelStream *) stream, "</tt></td></tr></table>\n");
    camel_object_unref (filtered_stream);
    
    return TRUE;
}

static gboolean
handle_text_html (CamelMimePart *part, const char *mime_type,
          MailDisplay *md, MailDisplayStream *stream)
{
    const char *location, *base;
    
    camel_stream_write_string ((CamelStream *) stream, "\n<!-- text/html -->\n");
    
    if ((base = camel_medium_get_header (CAMEL_MEDIUM (part), "Content-Base"))) {
        char *base_url;
        size_t len;
        
        len = strlen (base);
        
        if (*base == '"' && *(base + len - 1) == '"') {
            len -= 2;
            base_url = g_alloca (len + 1);
            memcpy (base_url, base + 1, len);
            base_url[len] = '\0';
            base = base_url;
        }
        
        gtk_html_set_base (md->html, base);
    }
    
    location = get_location (part, md);
    if (!location)
        location = get_cid (part, md);
    
    camel_stream_printf ((CamelStream *) stream, "<iframe src=\"%s\" frameborder=0 "
                 "scrolling=no>could not get %s</iframe>", location, location);
    
    return TRUE;
}

static gboolean
handle_image (CamelMimePart *part, const char *mime_type, MailDisplay *md, MailDisplayStream *stream)
{
    camel_stream_printf ((CamelStream *) stream, "<img hspace=10 vspace=10 src=\"%s\">",
                 get_cid (part, md));
    return TRUE;
}

static gboolean
handle_multipart_mixed (CamelMimePart *part, const char *mime_type,
            MailDisplay *md, MailDisplayStream *stream)
{
    CamelDataWrapper *wrapper =
        camel_medium_get_content_object (CAMEL_MEDIUM (part));
    CamelMultipart *mp;
    int i, nparts;
    gboolean output = FALSE;
    
    if (!CAMEL_IS_MULTIPART (wrapper)) {
        mail_error_printf (stream, "\n%s\n", _("Could not parse MIME message. Displaying as source."));
        if (mail_content_loaded (wrapper, md, TRUE, NULL, md->html, NULL))
            handle_text_plain (part, "text/plain", md, stream);
        return TRUE;
    }
    
    mp = CAMEL_MULTIPART (wrapper);
    
    nparts = camel_multipart_get_number (mp);   
    for (i = 0; i < nparts; i++) {
        if (i != 0 && output)
            write_hr (stream);
        
        part = camel_multipart_get_part (mp, i);
        
        output = format_mime_part (part, md, stream);
    }
    
    return TRUE;
}

static gboolean
handle_multipart_encrypted (CamelMimePart *part, const char *mime_type,
                MailDisplay *md, MailDisplayStream *stream)
{
    CamelMultipartEncrypted *mpe;
    CamelMimePart *mime_part;
    CamelCipherContext *cipher;
    CamelDataWrapper *wrapper;
    CamelException ex;
    gboolean handled;
    
    /* Currently we only handle RFC2015-style PGP encryption. */
    if (!camel_pgp_mime_is_rfc2015_encrypted (part))
        return handle_multipart_mixed (part, mime_type, md, stream);
    
    wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (part));
    
    mpe = CAMEL_MULTIPART_ENCRYPTED (wrapper);
    
    camel_exception_init (&ex);
    cipher = camel_gpg_context_new (session);
    mime_part = camel_multipart_encrypted_decrypt (mpe, cipher, &ex);
    camel_object_unref (cipher);
    
    if (camel_exception_is_set (&ex)) {
        mail_error_printf (stream, "\n%s\n", camel_exception_get_description (&ex));
        camel_exception_clear (&ex);
        return TRUE;
    }
    
    handled = format_mime_part (mime_part, md, stream);
    camel_object_unref (mime_part);
    
    return handled;
}

static gboolean
handle_multipart_signed (CamelMimePart *part, const char *mime_type,
             MailDisplay *md, MailDisplayStream *stream)
{
    CamelMimePart *subpart;
    CamelDataWrapper *wrapper;
    CamelMultipartSigned *mps;
    gboolean output = FALSE;
    
    wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (part));
    
    if (!CAMEL_IS_MULTIPART_SIGNED (wrapper)) {
        mail_error_printf (stream, "\n%s\n", _("Could not parse MIME message. Displaying as source."));
        if (mail_content_loaded (wrapper, md, TRUE, NULL, md->html, NULL))
            handle_text_plain (part, "text/plain", md, stream);
        return TRUE;
    }
    
    mps = CAMEL_MULTIPART_SIGNED (wrapper);
    
    /* if subpart & signature is null, what do we do?  just write it out raw?
       multipart_signed will, if it cannot parse properly, put everything in the first part
       this includes: more or less than 2 parts */
    
    /* output the content */
    subpart = camel_multipart_get_part ((CamelMultipart *) mps, CAMEL_MULTIPART_SIGNED_CONTENT);
    if (subpart == NULL)
        return FALSE;
    
    output = format_mime_part (subpart, md, stream);
    
    /* now handle the signature */
    subpart = camel_multipart_get_part ((CamelMultipart *) mps, CAMEL_MULTIPART_SIGNED_SIGNATURE);
    if (subpart == NULL)
        return FALSE;
    
    mail_part_set_default_displayed_inline (subpart, md, FALSE);
    
    if (!mail_part_is_displayed_inline (subpart, md) && !md->printing) {
        char *url;
        
        /* Write out the click-for-info object */
        url = g_strdup_printf ("signature:%p/%lu", subpart,
                       (unsigned long)time (NULL));
        camel_stream_printf ((CamelStream *) stream,
                     "<br><table cellspacing=0 cellpadding=0>"
                     "<tr><td><table width=10 cellspacing=0 cellpadding=0>"
                     "<tr><td></td></tr></table></td>"
                     "<td><object classid=\"%s\"></object></td>"
                     "<td><table width=3 cellspacing=0 cellpadding=0>"
                     "<tr><td></td></tr></table></td>"
                     "<td><font size=-1>", url);
        mail_display_add_url (md, "part_urls", url, subpart);
        
        camel_stream_write_string ((CamelStream *) stream,
                       _("This message is digitally signed. "
                         "Click the lock icon for more information."));
        
        camel_stream_write_string ((CamelStream *) stream, "</font></td></tr><tr><td height=10>"
                       "<table cellspacing=0 cellpadding=0><tr>"
                       "<td height=10><a name=\"glue\"></td></tr>"
                       "</table></td></tr></table>\n");
    } else {
        CamelCipherValidity *valid = NULL;
        CamelException ex;
        const char *message = NULL;
        gboolean good = FALSE;
        CamelCipherContext *cipher;
        
        /* Write out the verification results */
        /* TODO: use the right context for the right message ... */
        camel_exception_init (&ex);
        cipher = camel_gpg_context_new (session);
        if (cipher) {
            valid = camel_multipart_signed_verify (mps, cipher, &ex);
            camel_object_unref (cipher);
            if (valid) {
                good = camel_cipher_validity_get_valid (valid);
                message = camel_cipher_validity_get_description (valid);
            } else {
                message = camel_exception_get_description (&ex);
            }
        } else {
            message = _("Could not create a PGP verfication context");
        }
        
        if (good) {
            camel_stream_printf ((CamelStream *) stream, "<table><tr valign=top><td>"
                         "<img src=\"%s\"></td><td>%s<br><br>",
                         mail_display_get_url_for_icon (md, EVOLUTION_ICONSDIR
                                        "/pgp-signature-ok.png"),
                         _("This message is digitally signed and "
                           "has been found to be authentic."));
        } else {
            camel_stream_printf ((CamelStream *) stream, "<table><tr valign=top><td>"
                         "<img src=\"%s\"></td><td>%s<br><br>",
                         mail_display_get_url_for_icon (md, EVOLUTION_ICONSDIR
                                        "/pgp-signature-bad.png"),
                         _("This message is digitally signed but can "
                           "not be proven to be authentic."));
        }
        
        if (message) {
            camel_stream_printf ((CamelStream *) stream, "<font size=-1%s>", good ||
                         md->printing ? "" : " color=red");
            mail_text_write (stream, md, part, 0, md->printing, message);
            camel_stream_write_string ((CamelStream *) stream, "</font>");
        }
        
        camel_stream_write_string ((CamelStream *) stream, "</td></tr></table>");
        camel_exception_clear (&ex);
        camel_cipher_validity_free (valid);
    }
    
    return TRUE;
}

/* As seen in RFC 2387! */
static gboolean
handle_multipart_related (CamelMimePart *part, const char *mime_type,
              MailDisplay *md, MailDisplayStream *stream)
{
    CamelDataWrapper *wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (part));
    CamelMultipart *mp;
    CamelMimePart *body_part, *display_part = NULL;
    CamelContentType *content_type;
    const char *location, *start;
    int i, nparts;
    GHashTable *related_save;
    int ret;
    
    if (!CAMEL_IS_MULTIPART (wrapper)) {
        mail_error_printf (stream, "\n%s\n", _("Could not parse MIME message. Displaying as source."));
        if (mail_content_loaded (wrapper, md, TRUE, NULL, md->html, NULL))
            handle_text_plain (part, "text/plain", md, stream);
        return TRUE;
    }
    
    mp = CAMEL_MULTIPART (wrapper);
    nparts = camel_multipart_get_number (mp);   
    
    content_type = camel_mime_part_get_content_type (part);
    start = header_content_type_param (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 (cid && !strncmp (cid, start + 1, len) && strlen (cid) == len) {
                display_part = body_part;
                break;
            }
        }
    } else {
        /* No start parameter, so it defaults to the first part. */
        display_part = camel_multipart_get_part (mp, 0);
    }
    
    if (!display_part) {
        /* Oops. Hrmph. */
        return handle_multipart_mixed (part, mime_type, md, stream);
    }
    
    /* setup a 'stack' of related parts */
    related_save = md->related;
    md->related = g_hash_table_new(NULL, NULL);
    
    location = camel_mime_part_get_content_location (part);
    if (location)
        mail_display_push_content_location (md, location);
    
    /* Record the Content-ID/Content-Location of any non-displayed parts. */
    for (i = 0; i < nparts; i++) {
        body_part = camel_multipart_get_part (mp, i);
        if (body_part == display_part)
            continue;
        
        get_cid (body_part, md);
        get_location (body_part, md);
        g_hash_table_insert (md->related, body_part, body_part);
    }
    
    /* Now, display the displayed part. */
    ret = format_mime_part (display_part, md, stream);
    
    /* FIXME: flush html stream via gtkhtml_stream_flush which doens't exist yet ... */
    while (gtk_events_pending ())
        gtk_main_iteration ();
    
    /* Now check for related parts which didn't display, display them as attachments */
    for (i = 0; i < nparts; i++) {
        body_part = camel_multipart_get_part (mp, i);
        if (body_part == display_part)
            continue;
        
        if (g_hash_table_lookup (md->related, body_part)) {
            if (ret)
                write_hr (stream);
            ret |= format_mime_part (body_part, md, stream);
        }
    }
    
    g_hash_table_destroy (md->related);
    md->related = related_save;
    
    if (location)
        mail_display_pop_content_location (md);
    
    return ret;
}

/* RFC 2046 says "display the last part that you are able to display". */
static CamelMimePart *
find_preferred_alternative (CamelMultipart *multipart, gboolean want_plain)
{
    int i, nparts;
    CamelMimePart *preferred_part = NULL;
    MailMimeHandler *handler;
    
    nparts = camel_multipart_get_number (multipart);
    for (i = 0; i < nparts; i++) {
        CamelMimePart *part = camel_multipart_get_part (multipart, i);
        CamelContentType *type = camel_mime_part_get_content_type (part);
        char *mime_type = header_content_type_simple (type);
        
        camel_strdown (mime_type);
        if (want_plain && !strcmp (mime_type, "text/plain"))
            return part;
        handler = mail_lookup_handler (mime_type);
        if (handler && (!preferred_part || !handler->generic))
            preferred_part = part;
        g_free (mime_type);
    }
    
    return preferred_part;
}

static gboolean
handle_multipart_alternative (CamelMimePart *part, const char *mime_type,
                  MailDisplay *md, MailDisplayStream *stream)
{
    CamelDataWrapper *wrapper =
        camel_medium_get_content_object (CAMEL_MEDIUM (part));
    CamelMultipart *multipart;
    CamelMimePart *mime_part;
    
    if (!CAMEL_IS_MULTIPART (wrapper)) {
        mail_error_printf (stream, "\n%s\n", _("Could not parse MIME message. Displaying as source."));
        if (mail_content_loaded (wrapper, md, TRUE, NULL, md->html, NULL))
            handle_text_plain (part, "text/plain", md, stream);
        return TRUE;
    }
    
    multipart = CAMEL_MULTIPART (wrapper);
    
    mime_part = find_preferred_alternative (multipart, FALSE);
    if (mime_part)
        return format_mime_part (mime_part, md, stream);
    else
        return handle_multipart_mixed (part, mime_type, md, stream);
}

/* RFC 1740 */
static gboolean
handle_multipart_appledouble (CamelMimePart *part, const char *mime_type,
                  MailDisplay *md, MailDisplayStream *stream)
{
    CamelDataWrapper *wrapper =
        camel_medium_get_content_object (CAMEL_MEDIUM (part));
    CamelMultipart *multipart;
    
    if (!CAMEL_IS_MULTIPART (wrapper)) {
        mail_error_printf (stream, "\n%s\n", _("Could not parse MIME message. Displaying as source."));
        if (mail_content_loaded (wrapper, md, TRUE, NULL, md->html, NULL))
            handle_text_plain (part, "text/plain", md, stream);
        return TRUE;
    }
    
    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);
    return format_mime_part (part, md, stream);
}

static gboolean
handle_message_rfc822 (CamelMimePart *part, const char *mime_type,
               MailDisplay *md, MailDisplayStream *stream)
{
    CamelDataWrapper *wrapper =
        camel_medium_get_content_object (CAMEL_MEDIUM (part));
    
    g_return_val_if_fail (CAMEL_IS_MIME_MESSAGE (wrapper), FALSE);
    
    camel_stream_write_string ((CamelStream *) stream, "<blockquote>");
    mail_format_mime_message (CAMEL_MIME_MESSAGE (wrapper), md, stream);
    camel_stream_write_string ((CamelStream *) stream, "</blockquote>");
    
    return TRUE;
}

static gboolean
handle_message_external_body (CamelMimePart *part, const char *mime_type,
                  MailDisplay *md, MailDisplayStream *stream)
{
    CamelContentType *type;
    const char *access_type;
    char *url = NULL, *desc = NULL;
    
    type = camel_mime_part_get_content_type (part);
    access_type = header_content_type_param (type, "access-type");
    if (!access_type)
        goto fallback;
    
    if (!strcasecmp (access_type, "ftp") ||
        !strcasecmp (access_type, "anon-ftp")) {
        const char *name, *site, *dir, *mode, *ftype;
        char *path;
        
        name = header_content_type_param (type, "name");
        site = header_content_type_param (type, "site");
        if (name == NULL || site == NULL)
            goto fallback;
        dir = header_content_type_param (type, "directory");
        mode = header_content_type_param (type, "mode");
        
        /* Generate the path. */
        if (dir) {
            const char *p = dir + strlen (dir);
            
            path = g_strdup_printf ("%s%s%s%s",
                        *dir == '/' ? "" : "/",
                        dir,
                        *p == '/' ? "" : "/",
                        name);
        } else {
            path = g_strdup_printf ("%s%s",
                        *name == '/' ? "" : "/",
                        name);
        }
        
        if (mode && *mode == 'A')
            ftype = ";type=A";
        else if (mode && *mode == 'I')
            ftype = ";type=I";
        else
            ftype = "";
        
        url = g_strdup_printf ("ftp://%s%s%s", site, path, ftype);
        g_free (path);
        desc = g_strdup_printf (_("Pointer to FTP site (%s)"), url);
    } else if (!g_ascii_strcasecmp (access_type, "local-file")) {
        const char *name, *site;
        
        name = header_content_type_param (type, "name");
        if (name == NULL)
            goto fallback;
        site = header_content_type_param (type, "site");
        
        url = g_strdup_printf ("file://%s%s", *name == '/' ? "" : "/", name);
        if (site) {
            desc = g_strdup_printf(_("Pointer to local file (%s) "
                         "valid at site \"%s\""), name, site);
        } else {
            desc = g_strdup_printf(_("Pointer to local file (%s)"), name);
        }
    } else if (!strcasecmp (access_type, "URL")) {
        const char *urlparam;
        char *s, *d;
        
        /* RFC 2017 */
        
        urlparam = header_content_type_param (type, "url");
        if (urlparam == NULL)
            goto fallback;
        
        /* For obscure MIMEy reasons, the URL may be split into
         * multiple words, and needs to be rejoined. (The URL
         * must have any real whitespace %-encoded, so we just
         * get rid of all of it.
         */
        url = g_strdup (urlparam);
        s = d = url;
        
        while (*s) {
            if (!isspace ((unsigned char)*s))
                *d++ = *s;
            s++;
        }
        *d = *s;
        
        desc = g_strdup_printf (_("Pointer to remote data (%s)"), url);
    }
    
 fallback:
    if (!desc) {
        if (access_type)
            desc = g_strdup_printf (_("Pointer to unknown external data (\"%s\" type)"), access_type);
        else
            desc = g_strdup (_("Malformed external-body part."));
    }
    
#if 0 /* FIXME */
    handle_mystery (part, md, url, "gnome-globe.png", desc,
            url ? "open it in a browser" : NULL);
#endif
    
    g_free (desc);
    g_free (url);
    
    return TRUE;
}

static gboolean
handle_via_bonobo (CamelMimePart *part, const char *mime_type,
           MailDisplay *md, MailDisplayStream *stream)
{
    if (!md->printing) {
        camel_stream_printf ((CamelStream *) stream,
                     "<object classid=\"%s\" type=\"%s\"></object>",
                     get_cid (part, md), mime_type);
    }
    
    return TRUE;
}

/**
 * mail_get_message_rfc822:
 * @message: the message
 * @want_plain: whether the caller prefers plain to html
 * @cite: whether or not to cite the message text
 *
 * See mail_get_message_body() below for more details.
 *
 * Return value: an HTML string representing the text parts of @message.
 **/
static char *
mail_get_message_rfc822 (CamelMimeMessage *message, gboolean want_plain, gboolean cite)
{
    CamelDataWrapper *contents;
    GString *retval;
    const CamelInternetAddress *cia;
    char *text, *citation, *buf, *html;
    time_t date_val;
    int offset;
    
    contents = camel_medium_get_content_object (CAMEL_MEDIUM (message));
    text = mail_get_message_body (contents, want_plain, cite);
    if (!text)
        text = g_strdup ("");
    citation = cite ? "&gt; " : "";
    retval = g_string_new (NULL);
    
    /* Kludge: if text starts with "<PRE>", wrap it around the
     * headers too so we won't get a blank line between them for the
     * <P> to <PRE> switch.
     */
    if (!strncasecmp (text, "<pre>", 5))
        g_string_append_printf (retval, "<PRE>");
    
    /* create credits */
    cia = camel_mime_message_get_from (message);
    buf = camel_address_format (CAMEL_ADDRESS (cia));
    if (buf) {
        html = camel_text_to_html (buf, CAMEL_MIME_FILTER_TOHTML_CONVERT_NL, 0);
        g_string_append_printf (retval, "%s<b>From:</b> %s<br>",
                    citation, html);
        g_free (html);
        g_free (buf);
    }
    
    cia = camel_mime_message_get_recipients (message, CAMEL_RECIPIENT_TYPE_TO);
    buf = camel_address_format (CAMEL_ADDRESS (cia));
    if (buf) {
        html = camel_text_to_html (buf, CAMEL_MIME_FILTER_TOHTML_CONVERT_NL, 0);
        g_string_append_printf (retval, "%s<b>To:</b> %s<br>",
                    citation, html);
        g_free (html);
        g_free (buf);
    }
    
    cia = camel_mime_message_get_recipients (message, CAMEL_RECIPIENT_TYPE_CC);
    buf = camel_address_format (CAMEL_ADDRESS (cia));
    if (buf) {
        html = camel_text_to_html (buf, CAMEL_MIME_FILTER_TOHTML_CONVERT_NL, 0);
        g_string_append_printf (retval, "%s<b>Cc:</b> %s<br>",
                    citation, html);
        g_free (html);
        g_free (buf);
    }
    
    buf = (char *) camel_mime_message_get_subject (message);
    if (buf) {
        html = camel_text_to_html (buf, CAMEL_MIME_FILTER_TOHTML_CONVERT_NL |
                       CAMEL_MIME_FILTER_TOHTML_CONVERT_URLS, 0);
        g_string_append_printf (retval, "%s<b>Subject:</b> %s<br>",
                    citation, html);
        g_free (html);
    }
    
    date_val = camel_mime_message_get_date (message, &offset);
    buf = header_format_date (date_val, offset);
    html = camel_text_to_html (buf, CAMEL_MIME_FILTER_TOHTML_CONVERT_NL, 0);
    g_string_append_printf (retval, "%s<b>Date:</b> %s<br>", citation, html);
    g_free (html);
    g_free (buf);
    
    if (!strncasecmp (text, "<pre>", 5))
        g_string_append_printf (retval, "%s<br>%s", citation, text + 5);
    else
        g_string_append_printf (retval, "%s<br>%s", citation, text);
    g_free (text);
    
    buf = retval->str;
    g_string_free (retval, FALSE);
    
    return buf;
}

/**
 * mail_get_message_body:
 * @data: the message or mime part content
 * @want_plain: whether the caller prefers plain to html
 * @cite: whether or not to cite the message text
 *
 * This creates an HTML string representing @data. If @want_plain is %TRUE,
 * it will be an HTML string that looks like a text/plain representation
 * of @data (but it will still be HTML).
 *
 * If @cite is %TRUE, the message will be cited as a reply, using "> "s.
 *
 * Return value: the HTML string, which the caller must free, or
 * %NULL if @data doesn't include any data which should be forwarded or
 * replied to.
 **/
char *
mail_get_message_body (CamelDataWrapper *data, gboolean want_plain, gboolean cite)
{
    char *subtext, *old, *div, *text = NULL;
    CamelContentType *mime_type;
    CamelCipherContext *cipher;
    GByteArray *bytes = NULL;
    CamelMimePart *subpart;
    CamelMultipart *mp;
    int i, nparts;
    
    mime_type = camel_data_wrapper_get_mime_type_field (data);
    
    /* If it is message/rfc822 or message/news, extract the
     * important headers and recursively process the body.
     */
    if (header_content_type_is (mime_type, "message", "rfc822") ||
        header_content_type_is (mime_type, "message", "news"))
        return mail_get_message_rfc822 (CAMEL_MIME_MESSAGE (data), want_plain, cite);
    
    /* If it's a vcard or icalendar, ignore it. */
    if (header_content_type_is (mime_type, "text", "x-vcard") ||
        header_content_type_is (mime_type, "text", "calendar"))
        return NULL;
    
    /* Get the body data for other text/ or message/ types */
    if (header_content_type_is (mime_type, "text", "*") ||
        header_content_type_is (mime_type, "message", "*")) {
        bytes = mail_format_get_data_wrapper_text (data, NULL);
        
        if (bytes) {
            g_byte_array_append (bytes, "", 1);
            text = bytes->data;
            g_byte_array_free (bytes, FALSE);
        }
        
        if (text && !header_content_type_is (mime_type, "text", "html")) {
            char *html;
            
            html = camel_text_to_html (text, CAMEL_MIME_FILTER_TOHTML_PRE |
                           CAMEL_MIME_FILTER_TOHTML_CONVERT_URLS |
                           (cite ? CAMEL_MIME_FILTER_TOHTML_CITE : 0), 0);
            g_free (text);
            text = html;
        }
        return text;
    }
    
    /* If it's not message and it's not text, and it's not
     * multipart, we don't want to deal with it.
     */
    if (!header_content_type_is (mime_type, "multipart", "*"))
        return NULL;
    
    mp = CAMEL_MULTIPART (data);
    
    if (CAMEL_IS_MULTIPART_ENCRYPTED (mp)) {
        cipher = camel_gpg_context_new (session);
        subpart = camel_multipart_encrypted_decrypt (CAMEL_MULTIPART_ENCRYPTED (mp),
                                 cipher, NULL);
        if (!subpart)
            return NULL;
        
        data = camel_medium_get_content_object (CAMEL_MEDIUM (subpart));
        return mail_get_message_body (data, want_plain, cite);
    } else if (header_content_type_is (mime_type, "multipart", "alternative")) {
        /* Pick our favorite alternative and reply to it. */
        
        subpart = find_preferred_alternative (mp, want_plain);
        if (!subpart)
            return NULL;
        
        data = camel_medium_get_content_object (CAMEL_MEDIUM (subpart));
        return mail_get_message_body (data, want_plain, cite);
    }
    
    /* Otherwise, concatenate all the parts that we can. */
    if (want_plain) {
        if (cite)
            div = "<br>\n&gt; ----<br>\n&gt; <br>\n";
        else
            div = "<br>\n----<br>\n<br>\n";
    } else
        div = "<br><hr><br>";
    
    nparts = camel_multipart_get_number (mp);
    for (i = 0; i < nparts; i++) {
        subpart = camel_multipart_get_part (mp, i);
        
        /* only add to the body contents if it is marked as "inline" */
        if (!mail_part_is_inline (subpart))
            continue;
        
        data = camel_medium_get_content_object (CAMEL_MEDIUM (subpart));
        subtext = mail_get_message_body (data, want_plain, cite);
        if (!subtext)
            continue;
        
        if (text) {
            old = text;
            text = g_strdup_printf ("%s%s%s", old, div, subtext);
            g_free (subtext);
            g_free (old);
        } else
            text = subtext;
    }
    
    return text;
}