path: root/mail/em-format-html-display.c

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) version 3.
 *
 * 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with the program; if not, see <http://www.gnu.org/licenses/>
 *
 *
 * Authors:
 *      Michael Zucchi <notzed@ximian.com>
 *
 * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
 *
 */

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

#include <string.h>

#include <gtk/gtk.h>
#include <glib/gstdio.h>
#include <gdk/gdkkeysyms.h>

#ifdef G_OS_WIN32
/* Work around 'DATADIR' and 'interface' lossage in <windows.h> */
#define DATADIR crap_DATADIR
#include <windows.h>
#undef DATADIR
#undef interface
#endif

#include <gtkhtml/gtkhtml.h>
#include <gtkhtml/gtkhtml-embedded.h>

#include <glib/gi18n.h>

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

#include "e-util/e-datetime-format.h"
#include <e-util/e-dialog-utils.h>
#include <e-util/e-icon-factory.h>

#ifdef HAVE_NSS
#include "certificate-viewer.h"
#include "e-cert-db.h"
#endif

#include "e-mail-display.h"
#include "e-mail-attachment-bar.h"
#include "em-format-html-display.h"
#include "em-utils.h"
#include "widgets/misc/e-attachment-button.h"
#include "widgets/misc/e-attachment-view.h"

#define d(x)

struct _EMFormatHTMLDisplayPrivate {
    GtkWidget *attachment_view;  /* weak reference */
};

struct _smime_pobject {
    EMFormatHTMLPObject object;

    gint signature;
    CamelCipherValidity *valid;
    GtkWidget *widget;
};

/* TODO: move the dialogue elsehwere */
/* FIXME: also in em-format-html.c */
static const struct {
    const gchar *icon, *shortdesc, *description;
} smime_sign_table[5] = {
    { "stock_signature-bad", N_("Unsigned"), N_("This message is not signed. There is no guarantee that this message is authentic.") },
    { "stock_signature-ok", N_("Valid signature"), N_("This message is signed and is valid meaning that it is very likely that this message is authentic.") },
    { "stock_signature-bad", N_("Invalid signature"), N_("The signature of this message cannot be verified, it may have been altered in transit.") },
    { "stock_signature", N_("Valid signature, but cannot verify sender"), N_("This message is signed with a valid signature, but the sender of the message cannot be verified.") },
    { "stock_signature-bad", N_("Signature exists, but need public key"), N_("This message is signed with a signature, but there is no corresponding public key.") },

};

static const struct {
    const gchar *icon, *shortdesc, *description;
} smime_encrypt_table[4] = {
    { "stock_lock-broken", N_("Unencrypted"), N_("This message is not encrypted. Its content may be viewed in transit across the Internet.") },
    { "stock_lock-ok", N_("Encrypted, weak"), N_("This message is encrypted, but with a weak encryption algorithm. It would be difficult, but not impossible for an outsider to view the content of this message in a practical amount of time.") },
    { "stock_lock-ok", N_("Encrypted"), N_("This message is encrypted.  It would be difficult for an outsider to view the content of this message.") },
    { "stock_lock-ok", N_("Encrypted, strong"), N_("This message is encrypted, with a strong encryption algorithm. It would be very difficult for an outsider to view the content of this message in a practical amount of time.") },
};

static const gchar *smime_sign_colour[5] = {
    "", " bgcolor=\"#88bb88\"", " bgcolor=\"#bb8888\"", " bgcolor=\"#e8d122\"",""
};

static void efhd_attachment_frame (EMFormat *emf, CamelStream *stream, EMFormatPURI *puri, GCancellable *cancellable);
static void efhd_message_add_bar (EMFormat *emf, CamelStream *stream, CamelMimePart *part, const EMFormatHandler *info);
static gboolean efhd_attachment_button (EMFormatHTML *efh, GtkHTMLEmbedded *eb, EMFormatHTMLPObject *pobject);
static gboolean efhd_attachment_optional (EMFormatHTML *efh, GtkHTMLEmbedded *eb, EMFormatHTMLPObject *object);

struct _attach_puri {
    EMFormatPURI puri;

    const EMFormatHandler *handle;

    const gchar *snoop_mime_type;

    /* for the > and V buttons */
    GtkWidget *forward, *down;
    /* currently no way to correlate this data to the frame :( */
    GtkHTML *frame;
    guint shown:1;

    /* Embedded Frame */
    GtkHTMLEmbedded *html;

    /* Attachment */
    EAttachment *attachment;

    /* image stuff */
    gint fit_width;
    gint fit_height;
    GtkImage *image;
    GtkWidget *event_box;

    /* Optional Text Mem Stream */
    CamelStreamMem *mstream;

    /* Signed / Encrypted */
        camel_cipher_validity_sign_t sign;
        camel_cipher_validity_encrypt_t encrypt;
};

static void efhd_message_prefix     (EMFormat *emf,
                         CamelStream *stream,
                         CamelMimePart *part,
                         const EMFormatHandler *info,
                         GCancellable *cancellable,
                         gboolean is_fallback);

static void efhd_builtin_init (EMFormatHTMLDisplayClass *efhc);

static gpointer parent_class;

static void
efhd_xpkcs7mime_free (EMFormatHTMLPObject *o)
{
    struct _smime_pobject *po = (struct _smime_pobject *)o;

    if (po->widget)
        gtk_widget_destroy (po->widget);
    camel_cipher_validity_free (po->valid);
}

static void
efhd_xpkcs7mime_info_response (GtkWidget *widget,
                               guint button,
                               struct _smime_pobject *po)
{
    gtk_widget_destroy (widget);
    po->widget = NULL;
}

#ifdef HAVE_NSS
static void
efhd_xpkcs7mime_viewcert_clicked (GtkWidget *button,
                                  struct _smime_pobject *po)
{
    CamelCipherCertInfo *info = g_object_get_data((GObject *)button, "e-cert-info");
    ECert *ec = NULL;

    if (info->cert_data)
        ec = e_cert_new (CERT_DupCertificate (info->cert_data));

    if (ec != NULL) {
        GtkWidget *w = certificate_viewer_show (ec);

        /* oddly enough certificate_viewer_show doesn't ... */
        gtk_widget_show (w);
        g_signal_connect(w, "response", G_CALLBACK(gtk_widget_destroy), NULL);

        if (w && po->widget)
            gtk_window_set_transient_for ((GtkWindow *)w, (GtkWindow *)po->widget);

        g_object_unref (ec);
    } else {
        g_warning("can't find certificate for %s <%s>", info->name?info->name:"", info->email?info->email:"");
    }
}
#endif

static void
efhd_xpkcs7mime_add_cert_table (GtkWidget *vbox,
                                CamelDList *certlist,
                                struct _smime_pobject *po)
{
    CamelCipherCertInfo *info = (CamelCipherCertInfo *)certlist->head;
    GtkTable *table = (GtkTable *)gtk_table_new (camel_dlist_length (certlist), 2, FALSE);
    gint n = 0;

    while (info->next) {
        gchar *la = NULL;
        const gchar *l = NULL;

        if (info->name) {
            if (info->email && strcmp (info->name, info->email) != 0)
                l = la = g_strdup_printf("%s <%s>", info->name, info->email);
            else
                l = info->name;
        } else {
            if (info->email)
                l = info->email;
        }

        if (l) {
            GtkWidget *w;
#if defined(HAVE_NSS)
            ECert *ec = NULL;
#endif
            w = gtk_label_new (l);
            gtk_misc_set_alignment ((GtkMisc *)w, 0.0, 0.5);
            g_free (la);
            gtk_table_attach (table, w, 0, 1, n, n+1, GTK_FILL, GTK_FILL, 3, 3);
#if defined(HAVE_NSS)
            w = gtk_button_new_with_mnemonic(_("_View Certificate"));
            gtk_table_attach (table, w, 1, 2, n, n+1, 0, 0, 3, 3);
            g_object_set_data((GObject *)w, "e-cert-info", info);
            g_signal_connect(w, "clicked", G_CALLBACK(efhd_xpkcs7mime_viewcert_clicked), po);

            if (info->cert_data)
                ec = e_cert_new (CERT_DupCertificate (info->cert_data));

            if (ec == NULL)
                gtk_widget_set_sensitive (w, FALSE);
            else
                g_object_unref (ec);
#else
            w = gtk_label_new (_("This certificate is not viewable"));
            gtk_table_attach (table, w, 1, 2, n, n+1, 0, 0, 3, 3);
#endif
            n++;
        }

        info = info->next;
    }

    gtk_box_pack_start ((GtkBox *)vbox, (GtkWidget *)table, TRUE, TRUE, 6);
}

static void
efhd_xpkcs7mime_validity_clicked (GtkWidget *button,
                                  EMFormatHTMLPObject *pobject)
{
    struct _smime_pobject *po = (struct _smime_pobject *)pobject;
    GtkBuilder *builder;
    GtkWidget *vbox, *w;

    if (po->widget)
        /* FIXME: window raise? */
        return;

    builder = gtk_builder_new ();
    e_load_ui_builder_definition (builder, "mail-dialogs.ui");

    po->widget = e_builder_get_widget(builder, "message_security_dialog");

    vbox = e_builder_get_widget(builder, "signature_vbox");
    w = gtk_label_new (_(smime_sign_table[po->valid->sign.status].description));
    gtk_misc_set_alignment ((GtkMisc *)w, 0.0, 0.5);
    gtk_label_set_line_wrap ((GtkLabel *)w, TRUE);
    gtk_box_pack_start ((GtkBox *)vbox, w, TRUE, TRUE, 6);
    if (po->valid->sign.description) {
        GtkTextBuffer *buffer;

        buffer = gtk_text_buffer_new (NULL);
        gtk_text_buffer_set_text (buffer, po->valid->sign.description, strlen (po->valid->sign.description));
        w = g_object_new (gtk_scrolled_window_get_type (),
                 "hscrollbar_policy", GTK_POLICY_AUTOMATIC,
                 "vscrollbar_policy", GTK_POLICY_AUTOMATIC,
                 "shadow_type", GTK_SHADOW_IN,
                 "child", g_object_new(gtk_text_view_get_type(),
                               "buffer", buffer,
                               "cursor_visible", FALSE,
                               "editable", FALSE,
                               "width_request", 500,
                               "height_request", 160,
                               NULL),
                 NULL);
        g_object_unref (buffer);

        gtk_box_pack_start ((GtkBox *)vbox, w, TRUE, TRUE, 6);
    }

    if (!camel_dlist_empty (&po->valid->sign.signers))
        efhd_xpkcs7mime_add_cert_table (vbox, &po->valid->sign.signers, po);

    gtk_widget_show_all (vbox);

    vbox = e_builder_get_widget(builder, "encryption_vbox");
    w = gtk_label_new (_(smime_encrypt_table[po->valid->encrypt.status].description));
    gtk_misc_set_alignment ((GtkMisc *)w, 0.0, 0.5);
    gtk_label_set_line_wrap ((GtkLabel *)w, TRUE);
    gtk_box_pack_start ((GtkBox *)vbox, w, TRUE, TRUE, 6);
    if (po->valid->encrypt.description) {
        GtkTextBuffer *buffer;

        buffer = gtk_text_buffer_new (NULL);
        gtk_text_buffer_set_text (buffer, po->valid->encrypt.description, strlen (po->valid->encrypt.description));
        w = g_object_new (gtk_scrolled_window_get_type (),
                 "hscrollbar_policy", GTK_POLICY_AUTOMATIC,
                 "vscrollbar_policy", GTK_POLICY_AUTOMATIC,
                 "shadow_type", GTK_SHADOW_IN,
                 "child", g_object_new(gtk_text_view_get_type(),
                               "buffer", buffer,
                               "cursor_visible", FALSE,
                               "editable", FALSE,
                               "width_request", 500,
                               "height_request", 160,
                               NULL),
                 NULL);
        g_object_unref (buffer);

        gtk_box_pack_start ((GtkBox *)vbox, w, TRUE, TRUE, 6);
    }

    if (!camel_dlist_empty (&po->valid->encrypt.encrypters))
        efhd_xpkcs7mime_add_cert_table (vbox, &po->valid->encrypt.encrypters, po);

    gtk_widget_show_all (vbox);

    g_object_unref (builder);

    g_signal_connect(po->widget, "response", G_CALLBACK(efhd_xpkcs7mime_info_response), po);
    gtk_widget_show (po->widget);
}

static gboolean
efhd_xpkcs7mime_button (EMFormatHTML *efh,
                        GtkHTMLEmbedded *eb,
                        EMFormatHTMLPObject *pobject)
{
    GtkWidget *container;
    GtkWidget *widget;
    struct _smime_pobject *po = (struct _smime_pobject *)pobject;
    const gchar *icon_name;

    /* FIXME: need to have it based on encryption and signing too */
    if (po->valid->sign.status != 0)
        icon_name = smime_sign_table[po->valid->sign.status].icon;
    else
        icon_name = smime_encrypt_table[po->valid->encrypt.status].icon;

    container = GTK_WIDGET (eb);

    widget = gtk_button_new ();
    g_signal_connect (
        widget, "clicked",
        G_CALLBACK (efhd_xpkcs7mime_validity_clicked), pobject);
    gtk_container_add (GTK_CONTAINER (container), widget);
    gtk_widget_show (widget);

    container = widget;

    widget = gtk_image_new_from_icon_name (
        icon_name, GTK_ICON_SIZE_LARGE_TOOLBAR);
    gtk_container_add (GTK_CONTAINER (container), widget);
    gtk_widget_show (widget);

    return TRUE;
}

static void
efhd_format_clone (EMFormat *emf,
                   CamelFolder *folder,
                   const gchar *uid,
                   CamelMimeMessage *msg,
                   EMFormat *src,
                   GCancellable *cancellable)
{
    if (emf != src)
        EM_FORMAT_HTML (emf)->header_wrap_flags = 0;

    /* Chain up to parent's format_clone() method. */
    EM_FORMAT_CLASS (parent_class)->
        format_clone (emf, folder, uid, msg, src, cancellable);
}

static void
efhd_format_attachment (EMFormat *emf,
                        CamelStream *stream,
                        CamelMimePart *part,
                        const gchar *mime_type,
                        const EMFormatHandler *handle,
                        GCancellable *cancellable)
{
    gchar *classid, *text, *html;
    struct _attach_puri *info;

    classid = g_strdup_printf ("attachment%s", emf->part_id->str);
    info = (struct _attach_puri *) em_format_add_puri (
        emf, sizeof (*info), classid, part, efhd_attachment_frame);
    em_format_html_add_pobject (
        EM_FORMAT_HTML (emf), sizeof (EMFormatHTMLPObject),
        classid, part, efhd_attachment_button);
    info->handle = handle;
    info->shown = em_format_is_inline (
        emf, info->puri.part_id, info->puri.part, handle);
    info->snoop_mime_type = emf->snoop_mime_type;
    info->attachment = e_attachment_new ();
    e_attachment_set_mime_part (info->attachment, info->puri.part);

    if (emf->valid) {
        info->sign = emf->valid->sign.status;
        info->encrypt = emf->valid->encrypt.status;
    }

    camel_stream_write_string (
        stream, EM_FORMAT_HTML_VPAD
        "<table cellspacing=0 cellpadding=0><tr><td>"
        "<table width=10 cellspacing=0 cellpadding=0>"
        "<tr><td></td></tr></table></td>",
        cancellable, NULL);

    camel_stream_printf (
        stream, "<td><object classid=\"%s\"></object></td>", classid);

    camel_stream_write_string (
        stream, "<td><table width=3 cellspacing=0 cellpadding=0>"
        "<tr><td></td></tr></table></td><td><font size=-1>",
        cancellable, NULL);

    /* output some info about it */
    /* FIXME: should we look up mime_type from object again? */
    text = em_format_describe_part (part, mime_type);
    html = camel_text_to_html (
        text, EM_FORMAT_HTML (emf)->text_html_flags &
        CAMEL_MIME_FILTER_TOHTML_CONVERT_URLS, 0);
    camel_stream_write_string (stream, html, cancellable, NULL);
    g_free (html);
    g_free (text);

    camel_stream_write_string (
        stream, "</font></td></tr><tr></table>\n"
        EM_FORMAT_HTML_VPAD, cancellable, NULL);

    if (handle && info->shown)
        handle->handler (
            emf, stream, part, handle, cancellable, FALSE);

    g_free (classid);
}

static void
efhd_format_optional (EMFormat *emf,
                      CamelStream *fstream,
                      CamelMimePart *part,
                      CamelStream *mstream,
                      GCancellable *cancellable)
{
    gchar *classid, *html;
    struct _attach_puri *info;
    CamelStream *stream = NULL;

    if (CAMEL_IS_STREAM_FILTER (fstream))
        stream = camel_stream_filter_get_source (
            CAMEL_STREAM_FILTER (fstream));
    if (stream == NULL)
        stream = fstream;

    classid = g_strdup_printf ("optional%s", emf->part_id->str);
    info = (struct _attach_puri *) em_format_add_puri (
        emf, sizeof (*info), classid, part, efhd_attachment_frame);
    em_format_html_add_pobject (
        EM_FORMAT_HTML (emf), sizeof (EMFormatHTMLPObject),
        classid, part, efhd_attachment_optional);
    info->handle = em_format_find_handler (emf, "text/plain");
    info->shown = FALSE;
    info->snoop_mime_type = "text/plain";
    info->attachment = e_attachment_new ();
    e_attachment_set_mime_part (info->attachment, info->puri.part);
    info->mstream = (CamelStreamMem *) g_object_ref (mstream);
    if (emf->valid) {
        info->sign = emf->valid->sign.status;
        info->encrypt = emf->valid->encrypt.status;
    }

    camel_stream_write_string (
        stream, EM_FORMAT_HTML_VPAD
        "<table cellspacing=0 cellpadding=0><tr><td>"
        "<h3><font size=-1 color=red>", cancellable, NULL);

    html = camel_text_to_html (
        _("Evolution cannot render this email as it is too "
          "large to process. You can view it unformatted or "
          "with an external text editor."),
        EM_FORMAT_HTML (emf)->text_html_flags &
        CAMEL_MIME_FILTER_TOHTML_CONVERT_URLS, 0);
    camel_stream_write_string (stream, html, cancellable, NULL);
    camel_stream_write_string (
        stream, "</font></h3></td></tr></table>\n",
        cancellable, NULL);
    camel_stream_write_string (
        stream, "<table cellspacing=0 cellpadding=0><tr>",
        cancellable, NULL);
    camel_stream_printf (
        stream, "<td><object classid=\"%s\"></object>"
        "</td></tr></table>", classid);

    g_free (html);

    camel_stream_write_string (
        stream, EM_FORMAT_HTML_VPAD, cancellable, NULL);

    g_free (classid);
}

static void
efhd_format_secure (EMFormat *emf,
                    CamelStream *stream,
                    CamelMimePart *part,
                    CamelCipherValidity *valid,
                    GCancellable *cancellable)
{
    EMFormatClass *format_class;

    format_class = g_type_class_peek (EM_TYPE_FORMAT);
    format_class->format_secure (emf, stream, part, valid, cancellable);

    if (emf->valid == valid
        && (valid->encrypt.status != CAMEL_CIPHER_VALIDITY_ENCRYPT_NONE
        || valid->sign.status != CAMEL_CIPHER_VALIDITY_SIGN_NONE)) {
        gchar *classid;
        struct _smime_pobject *pobj;

        camel_stream_printf (
            stream, "<table border=0 width=\"100%%\" "
            "cellpadding=3 cellspacing=0%s><tr>",
            smime_sign_colour[valid->sign.status]);

        classid = g_strdup_printf (
            "smime:///em-format-html/%s/icon/signed",
            emf->part_id->str);
        pobj = (struct _smime_pobject *) em_format_html_add_pobject (
            EM_FORMAT_HTML (emf), sizeof (*pobj),
            classid, part, efhd_xpkcs7mime_button);
        pobj->valid = camel_cipher_validity_clone (valid);
        pobj->object.free = efhd_xpkcs7mime_free;
        camel_stream_printf (
            stream, "<td valign=center><object classid=\"%s\">"
            "</object></td><td width=100%% valign=center>",
            classid);
        g_free (classid);

        if (valid->sign.status != CAMEL_CIPHER_VALIDITY_SIGN_NONE) {
            gchar *signers;
            const gchar *desc;
            gint status;

            status = valid->sign.status;
            desc = smime_sign_table[status].shortdesc;

            camel_stream_printf (stream, "%s", gettext (desc));

            signers = em_format_html_format_cert_infos ((CamelCipherCertInfo *)valid->sign.signers.head);
            if (signers && *signers) {
                camel_stream_printf (stream, " (%s)", signers);
            }
            g_free (signers);
        }

        if (valid->encrypt.status != CAMEL_CIPHER_VALIDITY_ENCRYPT_NONE) {
            const gchar *desc;
            gint status;

            if (valid->sign.status != CAMEL_CIPHER_VALIDITY_SIGN_NONE) {
                camel_stream_printf (stream, "<br>");
            }

            status = valid->encrypt.status;
            desc = smime_encrypt_table[status].shortdesc;
            camel_stream_printf (stream, "%s", gettext (desc));
        }

        camel_stream_printf(stream, "</td></tr></table>");
    }
}

static void
efhd_class_init (EMFormatHTMLDisplayClass *class)
{
    EMFormatClass *format_class;
    EMFormatHTMLClass *format_html_class;

    parent_class = g_type_class_peek_parent (class);
    g_type_class_add_private (class, sizeof (EMFormatHTMLDisplayPrivate));

    format_class = EM_FORMAT_CLASS (class);
    format_class->format_clone = efhd_format_clone;
    format_class->format_attachment = efhd_format_attachment;
    format_class->format_optional = efhd_format_optional;
    format_class->format_secure = efhd_format_secure;

    format_html_class = EM_FORMAT_HTML_CLASS (class);
    format_html_class->html_widget_type = E_TYPE_MAIL_DISPLAY;

    efhd_builtin_init (class);
}

static void
efhd_init (EMFormatHTMLDisplay *efhd)
{
    EWebView *web_view;

    web_view = em_format_html_get_web_view (EM_FORMAT_HTML (efhd));

    efhd->priv = G_TYPE_INSTANCE_GET_PRIVATE (efhd, EM_TYPE_FORMAT_HTML_DISPLAY, EMFormatHTMLDisplayPrivate);

    e_mail_display_set_formatter (
        E_MAIL_DISPLAY (web_view), EM_FORMAT_HTML (efhd));

    /* we want to convert url's etc */
    EM_FORMAT_HTML (efhd)->text_html_flags |=
        CAMEL_MIME_FILTER_TOHTML_CONVERT_URLS |
        CAMEL_MIME_FILTER_TOHTML_CONVERT_ADDRESSES;
}

GType
em_format_html_display_get_type (void)
{
    static GType type = 0;

    if (G_UNLIKELY (type == 0)) {
        static const GTypeInfo type_info = {
            sizeof (EMFormatHTMLDisplayClass),
            (GBaseInitFunc) NULL,
            (GBaseFinalizeFunc) NULL,
            (GClassInitFunc) efhd_class_init,
            (GClassFinalizeFunc) NULL,
            NULL,  /* class_data */
            sizeof (EMFormatHTMLDisplay),
            0,     /* n_preallocs */
            (GInstanceInitFunc) efhd_init,
            NULL   /* value_table */
        };

        type = g_type_register_static (
            EM_TYPE_FORMAT_HTML, "EMFormatHTMLDisplay",
            &type_info, 0);
    }

    return type;
}

EMFormatHTMLDisplay *
em_format_html_display_new (void)
{
    return g_object_new (EM_TYPE_FORMAT_HTML_DISPLAY, NULL);
}

/* ********************************************************************** */

static EMFormatHandler type_builtin_table[] = {
    { (gchar *) "x-evolution/message/prefix", efhd_message_prefix },
    { (gchar *) "x-evolution/message/post-header", (EMFormatFunc)efhd_message_add_bar }
};

static void
efhd_builtin_init (EMFormatHTMLDisplayClass *efhc)
{
    gint i;

    for (i = 0; i < G_N_ELEMENTS (type_builtin_table); i++)
        em_format_class_add_handler ((EMFormatClass *)efhc, &type_builtin_table[i]);
}

static void
efhd_write_image (EMFormat *emf,
                  CamelStream *stream,
                  EMFormatPURI *puri,
                  GCancellable *cancellable)
{
    CamelDataWrapper *dw = camel_medium_get_content ((CamelMedium *)puri->part);

    /* TODO: identical to efh_write_image */
    d(printf("writing image '%s'\n", puri->cid));
    camel_data_wrapper_decode_to_stream_sync (
        dw, stream, cancellable, NULL);
    camel_stream_close (stream, cancellable, NULL);
}

static void
efhd_message_prefix (EMFormat *emf,
                     CamelStream *stream,
                     CamelMimePart *part,
                     const EMFormatHandler *info,
                     GCancellable *cancellable,
                     gboolean is_fallback)
{
    const gchar *flag, *comp, *due;
    time_t date;
    gchar *iconpath, *due_date_str;

    if (emf->folder == NULL || emf->uid == NULL
        || (flag = camel_folder_get_message_user_tag(emf->folder, emf->uid, "follow-up")) == NULL
        || flag[0] == 0)
        return;

    /* header displayed for message-flags in mail display */
    camel_stream_printf(stream, "<table border=1 width=\"100%%\" cellspacing=2 cellpadding=2><tr>");

    comp = camel_folder_get_message_user_tag(emf->folder, emf->uid, "completed-on");
    iconpath = e_icon_factory_get_icon_filename (comp && comp[0] ? "stock_mail-flag-for-followup-done" : "stock_mail-flag-for-followup", GTK_ICON_SIZE_MENU);
    if (iconpath) {
        CamelMimePart *iconpart;

        iconpart = em_format_html_file_part (
            (EMFormatHTML *)emf, "image/png",
            iconpath, cancellable);
        g_free (iconpath);
        if (iconpart) {
            gchar *classid;

            classid = g_strdup_printf("icon:///em-format-html-display/%s/%s", emf->part_id->str, comp&&comp[0]?"comp":"uncomp");
            camel_stream_printf(stream, "<td align=\"left\"><img src=\"%s\"></td>", classid);
            (void)em_format_add_puri (emf, sizeof (EMFormatPURI), classid, iconpart, efhd_write_image);
            g_free (classid);
            g_object_unref (iconpart);
        }
    }

    camel_stream_printf(stream, "<td align=\"left\" width=\"100%%\">");

    if (comp && comp[0]) {
        date = camel_header_decode_date (comp, NULL);
        due_date_str = e_datetime_format_format ("mail", "header", DTFormatKindDateTime, date);
        camel_stream_printf (stream, "%s, %s %s", flag, _("Completed on"), due_date_str ? due_date_str : "???");
        g_free (due_date_str);
    } else if ((due = camel_folder_get_message_user_tag(emf->folder, emf->uid, "due-by")) != NULL && due[0]) {
        time_t now;

        date = camel_header_decode_date (due, NULL);
        now = time (NULL);
        if (now > date)
            camel_stream_printf(stream, "<b>%s</b>&nbsp;", _("Overdue:"));

        due_date_str = e_datetime_format_format ("mail", "header", DTFormatKindDateTime, date);
        /* To Translators: the "by" is part of the string, like "Follow-up by Tuesday, January 13, 2009" */
        camel_stream_printf (stream, "%s %s %s", flag, _("by"), due_date_str ? due_date_str : "???");
    } else {
        camel_stream_printf(stream, "%s", flag);
    }

    camel_stream_printf(stream, "</td></tr></table>");
}

/* ********************************************************************** */

static void
efhd_attachment_button_expanded (EAttachmentButton *button,
                                 GParamSpec *pspec,
                                 struct _attach_puri *info)
{
    EMFormatHTML *efh;

    /* FIXME The PURI struct seems to have some lifecycle issues,
     *       because casting info->puri.format to an EMFormatHTML
     *       can lead to crashes.  So we hack around it. */
    efh = g_object_get_data (G_OBJECT (button), "efh");
    g_return_if_fail (EM_IS_FORMAT_HTML (efh));

    if (efh->state == EM_FORMAT_HTML_STATE_RENDERING)
        return;

    info->shown = e_attachment_button_get_expanded (button);

    em_format_set_inline (
        info->puri.format, info->puri.part_id, info->shown);
}

/* ********************************************************************** */

/* attachment button callback */
static gboolean
efhd_attachment_button (EMFormatHTML *efh, GtkHTMLEmbedded *eb, EMFormatHTMLPObject *pobject)
{
    EMFormatHTMLDisplay *efhd = (EMFormatHTMLDisplay *)efh;
    struct _attach_puri *info;
    EAttachmentView *view;
    EAttachmentStore *store;
    EAttachment *attachment;
    EWebView *web_view;
    GtkWidget *widget;
    gpointer parent;
    EMFormat *emf = (EMFormat *) efh;
    guint32 size = 0;

    /* FIXME: handle default shown case */
    d(printf("adding attachment button/content\n"));

    if (emf->folder && emf->folder->summary && emf->uid) {
        CamelMessageInfo *mi;

        mi = camel_folder_summary_uid (emf->folder->summary, emf->uid);
        if (mi) {
            const CamelMessageContentInfo *ci;

            ci = camel_folder_summary_guess_content_info (mi, camel_mime_part_get_content_type (pobject->part));
            if (ci) {
                size = ci->size;
                /* what if its not encoded in base64 ? is it a case to consider? */
                if (ci->encoding && !g_ascii_strcasecmp (ci->encoding, "base64"))
                    size = size/1.37;
            }
            camel_message_info_free (mi);
        }
    }

    info = (struct _attach_puri *)em_format_find_puri ((EMFormat *)efh, pobject->classid);

    if (!info || info->forward) {
        g_warning ("unable to expand the attachment\n");
        return TRUE;
    }

    attachment = info->attachment;
    e_attachment_set_shown (attachment, info->shown);
    e_attachment_set_signed (attachment, info->sign);
    e_attachment_set_encrypted (attachment, info->encrypt);
    e_attachment_set_can_show (attachment, info->handle != NULL);

    web_view = em_format_html_get_web_view (efh);
    parent = gtk_widget_get_toplevel (GTK_WIDGET (web_view));
    parent = gtk_widget_is_toplevel (parent) ? parent : NULL;

    view = em_format_html_display_get_attachment_view (efhd);
    gtk_widget_show (GTK_WIDGET (view));

    store = e_attachment_view_get_store (view);
    e_attachment_store_add_attachment (store, info->attachment);

    e_attachment_load_async (
        info->attachment, (GAsyncReadyCallback)
        e_attachment_load_handle_error, parent);
    if (size != 0) {
        GFileInfo *fileinfo;

        fileinfo = e_attachment_get_file_info (info->attachment);
        g_file_info_set_size (fileinfo, size);
        e_attachment_set_file_info (info->attachment, fileinfo);
    }

    widget = e_attachment_button_new (view);
    e_attachment_button_set_attachment (
        E_ATTACHMENT_BUTTON (widget), attachment);
    gtk_container_add (GTK_CONTAINER (eb), widget);
    gtk_widget_show (widget);

    /* FIXME Not sure why the expanded callback can't just use
     *       info->puri.format, but there seems to be lifecycle
     *       issues with the PURI struct.  Maybe it should have
     *       a reference count? */
    g_object_set_data (G_OBJECT (widget), "efh", efh);

    g_signal_connect (
        widget, "notify::expanded",
        G_CALLBACK (efhd_attachment_button_expanded), info);

    return TRUE;
}

static void
efhd_attachment_frame (EMFormat *emf,
                       CamelStream *stream,
                       EMFormatPURI *puri,
                       GCancellable *cancellable)
{
    struct _attach_puri *info = (struct _attach_puri *)puri;

    if (info->shown)
        info->handle->handler (
            emf, stream, info->puri.part,
            info->handle, cancellable, FALSE);

    camel_stream_close (stream, cancellable, NULL);
}

static void
efhd_bar_resize (EMFormatHTML *efh,
                 GtkAllocation *event)
{
    EMFormatHTMLDisplayPrivate *priv;
    GtkAllocation allocation;
    EWebView *web_view;
    GtkWidget *widget;
    gint width;

    priv = EM_FORMAT_HTML_DISPLAY (efh)->priv;

    web_view = em_format_html_get_web_view (efh);

    widget = GTK_WIDGET (web_view);
    gtk_widget_get_allocation (widget, &allocation);
    width = allocation.width - 12;

    if (width > 0) {
        widget = priv->attachment_view;
        gtk_widget_set_size_request (widget, width, -1);
    }
}

static gboolean
efhd_add_bar (EMFormatHTML *efh,
              GtkHTMLEmbedded *eb,
              EMFormatHTMLPObject *pobject)
{
    EMFormatHTMLDisplayPrivate *priv;
    GtkWidget *widget;

    /* XXX See note in efhd_message_add_bar(). */
    if (!EM_IS_FORMAT_HTML_DISPLAY (efh))
        return FALSE;

    priv = EM_FORMAT_HTML_DISPLAY (efh)->priv;

    widget = e_mail_attachment_bar_new ();
    gtk_container_add (GTK_CONTAINER (eb), widget);
    priv->attachment_view = widget;
    gtk_widget_hide (widget);

    g_signal_connect_swapped (
        eb, "size-allocate",
        G_CALLBACK (efhd_bar_resize), efh);

    return TRUE;
}

static void
efhd_message_add_bar (EMFormat *emf,
                      CamelStream *stream,
                      CamelMimePart *part,
                      const EMFormatHandler *info)
{
    const gchar *classid = "attachment-bar";

    /* XXX Apparently this installs the callback for -all-
     *     EMFormatHTML subclasses, not just this subclass.
     *     Bad idea.  So we have to filter out other types
     *     in the callback. */
    em_format_html_add_pobject (
        EM_FORMAT_HTML (emf),
        sizeof (EMFormatHTMLPObject),
        classid, part, efhd_add_bar);

    camel_stream_printf (
        stream, "<td><object classid=\"%s\"></object></td>", classid);
}

static void
efhd_optional_button_show (GtkWidget *widget, GtkWidget *w)
{
    GtkWidget *label = g_object_get_data (G_OBJECT (widget), "text-label");

    if (gtk_widget_get_visible (w)) {
        gtk_widget_hide (w);
        gtk_label_set_text_with_mnemonic (GTK_LABEL (label), _("View _Unformatted"));
    } else {
        gtk_label_set_text_with_mnemonic (GTK_LABEL (label), _("Hide _Unformatted"));
        gtk_widget_show (w);
    }
}

static void
efhd_resize (GtkWidget *w, GtkAllocation *event, EMFormatHTML *efh)
{
    EWebView *web_view;
    GtkAllocation allocation;

    web_view = em_format_html_get_web_view (efh);
    gtk_widget_get_allocation (GTK_WIDGET (web_view), &allocation);
    gtk_widget_set_size_request (w, allocation.width - 48, 250);
}

/* optional render attachment button callback */
static gboolean
efhd_attachment_optional (EMFormatHTML *efh, GtkHTMLEmbedded *eb, EMFormatHTMLPObject *pobject)
{
    struct _attach_puri *info;
    GtkWidget *hbox, *vbox, *button, *mainbox, *scroll, *label, *img;
    AtkObject *a11y;
    GtkWidget *view;
    GtkAllocation allocation;
    GtkTextBuffer *buffer;
    GByteArray *byte_array;
    EWebView *web_view;

    /* FIXME: handle default shown case */
    d(printf("adding attachment button/content for optional rendering\n"));

    info = (struct _attach_puri *)em_format_find_puri ((EMFormat *)efh, pobject->classid);
    if (!info || info->forward) {
        g_warning ("unable to expand the attachment\n");
        return TRUE;
    }

    scroll = gtk_scrolled_window_new (NULL, NULL);
    mainbox = gtk_hbox_new (FALSE, 0);

    button = gtk_button_new ();
    hbox = gtk_hbox_new (FALSE, 0);
    img = gtk_image_new_from_icon_name (
        "stock_show-all", GTK_ICON_SIZE_BUTTON);
    label = gtk_label_new_with_mnemonic(_("View _Unformatted"));
    g_object_set_data (G_OBJECT (button), "text-label", (gpointer)label);
    gtk_box_pack_start (GTK_BOX (hbox), img, TRUE, TRUE, 2);
    gtk_box_pack_start (GTK_BOX (hbox), label, TRUE, TRUE, 2);
    gtk_widget_show_all (hbox);
    gtk_container_add (GTK_CONTAINER (button), GTK_WIDGET (hbox));
    if (info->handle)
        g_signal_connect(G_OBJECT (button), "clicked", G_CALLBACK(efhd_optional_button_show), scroll);
    else {
        gtk_widget_set_sensitive (button, FALSE);
        gtk_widget_set_can_focus (button, FALSE);
    }

    vbox = gtk_vbox_new (FALSE, 0);
    gtk_box_pack_start (GTK_BOX (mainbox), button, FALSE, FALSE, 6);

    button = gtk_button_new ();
    hbox = gtk_hbox_new (FALSE, 0);
    img = gtk_image_new_from_stock (
        GTK_STOCK_OPEN, GTK_ICON_SIZE_BUTTON);
    label = gtk_label_new_with_mnemonic(_("O_pen With"));
    gtk_box_pack_start (GTK_BOX (hbox), img, TRUE, TRUE, 2);
    gtk_box_pack_start (GTK_BOX (hbox), label, TRUE, TRUE, 2);
    gtk_box_pack_start (GTK_BOX (hbox), gtk_arrow_new (GTK_ARROW_DOWN, GTK_SHADOW_NONE), TRUE, TRUE, 2);
    gtk_widget_show_all (hbox);
    gtk_container_add (GTK_CONTAINER (button), GTK_WIDGET (hbox));

    a11y = gtk_widget_get_accessible (button);
    atk_object_set_name (a11y, _("Attachment"));

    gtk_box_pack_start (GTK_BOX (mainbox), button, FALSE, FALSE, 6);

    gtk_widget_show_all (mainbox);

    gtk_box_pack_start (GTK_BOX (vbox), mainbox, FALSE, FALSE, 6);

    view = gtk_text_view_new ();
    gtk_text_view_set_editable (GTK_TEXT_VIEW (view), FALSE);
    gtk_text_view_set_cursor_visible (GTK_TEXT_VIEW (view), FALSE);
    buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view));
    byte_array = camel_stream_mem_get_byte_array (info->mstream);
    gtk_text_buffer_set_text (
        buffer, (gchar *) byte_array->data, byte_array->len);
    g_object_unref (info->mstream);
    info->mstream = NULL;
    gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (scroll),
                    GTK_POLICY_AUTOMATIC, GTK_POLICY_AUTOMATIC);
    gtk_scrolled_window_set_shadow_type (GTK_SCROLLED_WINDOW (scroll), GTK_SHADOW_IN);
    gtk_container_add (GTK_CONTAINER (scroll), GTK_WIDGET (view));
    gtk_box_pack_start (GTK_BOX (vbox), scroll, TRUE, TRUE, 6);
    gtk_widget_show (GTK_WIDGET (view));

    web_view = em_format_html_get_web_view (efh);
    gtk_widget_get_allocation (GTK_WIDGET (web_view), &allocation);
    gtk_widget_set_size_request (scroll, allocation.width - 48, 250);
    g_signal_connect (scroll, "size_allocate", G_CALLBACK(efhd_resize), efh);
    gtk_widget_show (scroll);

    if (!info->shown)
        gtk_widget_hide (scroll);

    gtk_widget_show (vbox);
    gtk_container_add (GTK_CONTAINER (eb), vbox);
    info->handle = NULL;

    return TRUE;
}

EAttachmentView *
em_format_html_display_get_attachment_view (EMFormatHTMLDisplay *html_display)
{
    g_return_val_if_fail (EM_IS_FORMAT_HTML_DISPLAY (html_display), NULL);

    return E_ATTACHMENT_VIEW (html_display->priv->attachment_view);
}