path: root/composer/e-composer-private.c

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

/*
 * 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.
 *
 * 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 Lesser General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 *
 * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
 */

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

#include "e-composer-private.h"
#include "e-composer-spell-header.h"
#include "e-util/e-util-private.h"

/* Initial height of the picture gallery. */
#define GALLERY_INITIAL_HEIGHT 150

static void
composer_setup_charset_menu (EMsgComposer *composer)
{
    GtkUIManager *ui_manager;
    const gchar *path;
    GList *list;
    guint merge_id;

    ui_manager = gtkhtml_editor_get_ui_manager (GTKHTML_EDITOR (composer));
    path = "/main-menu/options-menu/charset-menu";
    merge_id = gtk_ui_manager_new_merge_id (ui_manager);

    list = gtk_action_group_list_actions (composer->priv->charset_actions);
    list = g_list_sort (list, (GCompareFunc) e_action_compare_by_label);

    while (list != NULL) {
        GtkAction *action = list->data;

        gtk_ui_manager_add_ui (
            ui_manager, merge_id, path,
            gtk_action_get_name (action),
            gtk_action_get_name (action),
            GTK_UI_MANAGER_AUTO, FALSE);

        list = g_list_delete_link (list, list);
    }

    gtk_ui_manager_ensure_update (ui_manager);
}

static void
msg_composer_url_requested_cb (GtkHTML *html,
                               const gchar *uri,
                               GtkHTMLStream *stream,
                               EMsgComposer *composer)
{
    GByteArray *array;
    GHashTable *hash_table;
    CamelDataWrapper *wrapper;
    CamelStream *camel_stream;
    CamelMimePart *mime_part;

    hash_table = composer->priv->inline_images_by_url;
    mime_part = g_hash_table_lookup (hash_table, uri);

    if (mime_part == NULL) {
        hash_table = composer->priv->inline_images;
        mime_part = g_hash_table_lookup (hash_table, uri);
    }

    /* If this is not an inline image request,
     * allow the signal emission to continue. */
    if (mime_part == NULL)
        return;

    array = g_byte_array_new ();
    camel_stream = camel_stream_mem_new_with_byte_array (array);
    wrapper = camel_medium_get_content (CAMEL_MEDIUM (mime_part));
    camel_data_wrapper_decode_to_stream_sync (
        wrapper, camel_stream, NULL, NULL);

    gtk_html_write (html, stream, (gchar *) array->data, array->len);

    gtk_html_end (html, stream, GTK_HTML_STREAM_OK);

    g_object_unref (camel_stream);

    /* gtk_html_end() destroys the GtkHTMLStream, so we need to
     * stop the signal emission so nothing else tries to use it. */
    g_signal_stop_emission_by_name (html, "url-requested");
}

static void
composer_update_gallery_visibility (EMsgComposer *composer)
{
    GtkhtmlEditor *editor;
    GtkToggleAction *toggle_action;
    gboolean gallery_active;
    gboolean html_mode;

    editor = GTKHTML_EDITOR (composer);
    html_mode = gtkhtml_editor_get_html_mode (editor);

    toggle_action = GTK_TOGGLE_ACTION (ACTION (PICTURE_GALLERY));
    gallery_active = gtk_toggle_action_get_active (toggle_action);

    if (html_mode && gallery_active) {
        gtk_widget_show (composer->priv->gallery_scrolled_window);
        gtk_widget_show (composer->priv->gallery_icon_view);
    } else {
        gtk_widget_hide (composer->priv->gallery_scrolled_window);
        gtk_widget_hide (composer->priv->gallery_icon_view);
    }
}

static void
composer_spell_languages_changed (EMsgComposer *composer,
                                  GList *languages)
{
    EComposerHeader *header;
    EComposerHeaderTable *table;

    table = e_msg_composer_get_header_table (composer);
    header = e_composer_header_table_get_header (
        table, E_COMPOSER_HEADER_SUBJECT);

    e_composer_spell_header_set_languages (
        E_COMPOSER_SPELL_HEADER (header), languages);
}

void
e_composer_private_constructed (EMsgComposer *composer)
{
    EMsgComposerPrivate *priv = composer->priv;
    EFocusTracker *focus_tracker;
    EShell *shell;
    EWebViewGtkHTML *web_view;
    EClientCache *client_cache;
    GtkhtmlEditor *editor;
    GtkUIManager *ui_manager;
    GtkAction *action;
    GtkWidget *container;
    GtkWidget *widget;
    GtkWidget *send_widget;
    GtkWindow *window;
    GSettings *settings;
    const gchar *path;
    gchar *filename, *gallery_path;
    gint ii;
    GError *error = NULL;

    editor = GTKHTML_EDITOR (composer);
    ui_manager = gtkhtml_editor_get_ui_manager (editor);

    settings = g_settings_new ("org.gnome.evolution.mail");

    shell = e_msg_composer_get_shell (composer);
    client_cache = e_shell_get_client_cache (shell);
    web_view = e_msg_composer_get_web_view (composer);

    /* Each composer window gets its own window group. */
    window = GTK_WINDOW (composer);
    priv->window_group = gtk_window_group_new ();
    gtk_window_group_add_window (priv->window_group, window);

    priv->async_actions = gtk_action_group_new ("async");
    priv->charset_actions = gtk_action_group_new ("charset");
    priv->composer_actions = gtk_action_group_new ("composer");

    priv->extra_hdr_names = g_ptr_array_new ();
    priv->extra_hdr_values = g_ptr_array_new ();

    priv->inline_images = g_hash_table_new_full (
        g_str_hash, g_str_equal,
        (GDestroyNotify) g_free,
        (GDestroyNotify) NULL);

    priv->inline_images_by_url = g_hash_table_new_full (
        g_str_hash, g_str_equal,
        (GDestroyNotify) g_free,
        (GDestroyNotify) g_object_unref);

    priv->charset = e_composer_get_default_charset ();

    priv->is_from_message = FALSE;

    e_composer_actions_init (composer);

    filename = e_composer_find_data_file ("evolution-composer.ui");
    gtk_ui_manager_add_ui_from_file (ui_manager, filename, &error);
    g_free (filename);

    /* We set the send button as important to have a label */
    path = "/main-toolbar/pre-main-toolbar/send";
    send_widget = gtk_ui_manager_get_widget (ui_manager, path);
    gtk_tool_item_set_is_important (GTK_TOOL_ITEM (send_widget), TRUE);

    composer_setup_charset_menu (composer);

    if (error != NULL) {
        /* Henceforth, bad things start happening. */
        g_critical ("%s", error->message);
        g_clear_error (&error);
    }

    /* Configure an EFocusTracker to manage selection actions. */

    focus_tracker = e_focus_tracker_new (GTK_WINDOW (composer));

    action = gtkhtml_editor_get_action (editor, "cut");
    e_focus_tracker_set_cut_clipboard_action (focus_tracker, action);

    action = gtkhtml_editor_get_action (editor, "copy");
    e_focus_tracker_set_copy_clipboard_action (focus_tracker, action);

    action = gtkhtml_editor_get_action (editor, "paste");
    e_focus_tracker_set_paste_clipboard_action (focus_tracker, action);

    action = gtkhtml_editor_get_action (editor, "select-all");
    e_focus_tracker_set_select_all_action (focus_tracker, action);

    priv->focus_tracker = focus_tracker;

    container = editor->vbox;

    /* Construct the activity bar. */

    widget = e_activity_bar_new ();
    gtk_box_pack_start (GTK_BOX (container), widget, FALSE, FALSE, 0);
    priv->activity_bar = g_object_ref_sink (widget);
    /* EActivityBar controls its own visibility. */

    /* Construct the alert bar for errors. */

    widget = e_alert_bar_new ();
    gtk_box_pack_start (GTK_BOX (container), widget, FALSE, FALSE, 0);
    priv->alert_bar = g_object_ref_sink (widget);
    /* EAlertBar controls its own visibility. */

    /* Construct the header table. */

    widget = e_composer_header_table_new (client_cache);
    gtk_container_set_border_width (GTK_CONTAINER (widget), 6);
    gtk_box_pack_start (GTK_BOX (container), widget, FALSE, FALSE, 0);
    gtk_box_reorder_child (GTK_BOX (container), widget, 2);
    priv->header_table = g_object_ref_sink (widget);
    gtk_widget_show (widget);

    g_signal_connect (
        G_OBJECT (composer), "spell-languages-changed",
        G_CALLBACK (composer_spell_languages_changed), NULL);

    /* Construct the attachment paned. */

    widget = e_attachment_paned_new ();
    gtk_box_pack_start (GTK_BOX (container), widget, TRUE, TRUE, 0);
    priv->attachment_paned = g_object_ref_sink (widget);
    gtk_widget_show (widget);

    g_object_bind_property (
        web_view, "editable",
        widget, "editable",
        G_BINDING_SYNC_CREATE);

    container = e_attachment_paned_get_content_area (
        E_ATTACHMENT_PANED (priv->attachment_paned));

    widget = gtk_paned_new (GTK_ORIENTATION_VERTICAL);
    gtk_box_pack_start (GTK_BOX (container), widget, TRUE, TRUE, 0);
    gtk_widget_show (widget);

    container = widget;

    widget = gtk_scrolled_window_new (NULL, NULL);
    gtk_scrolled_window_set_policy (
        GTK_SCROLLED_WINDOW (widget),
        GTK_POLICY_AUTOMATIC, GTK_POLICY_AUTOMATIC);
    gtk_scrolled_window_set_shadow_type (
        GTK_SCROLLED_WINDOW (widget), GTK_SHADOW_IN);
    gtk_widget_set_size_request (widget, -1, GALLERY_INITIAL_HEIGHT);
    gtk_paned_pack1 (GTK_PANED (container), widget, FALSE, FALSE);
    priv->gallery_scrolled_window = g_object_ref_sink (widget);
    gtk_widget_show (widget);

    /* Reparent the scrolled window containing the GtkHTML widget
     * into the content area of the top attachment pane. */

    widget = GTK_WIDGET (web_view);
    widget = gtk_widget_get_parent (widget);
    gtk_widget_reparent (widget, container);

    /* Construct the picture gallery. */

    container = priv->gallery_scrolled_window;

    /* FIXME This should be an EMsgComposer property. */
    gallery_path = g_settings_get_string (
        settings, "composer-gallery-path");
    widget = e_picture_gallery_new (gallery_path);
    gtk_container_add (GTK_CONTAINER (container), widget);
    priv->gallery_icon_view = g_object_ref_sink (widget);
    g_free (gallery_path);

    g_signal_connect (
        composer, "notify::html-mode",
        G_CALLBACK (composer_update_gallery_visibility), NULL);

    g_signal_connect_swapped (
        ACTION (PICTURE_GALLERY), "toggled",
        G_CALLBACK (composer_update_gallery_visibility), composer);

    /* XXX What is this for? */
    g_object_set_data (G_OBJECT (composer), "vbox", editor->vbox);

    /* Bind headers to their corresponding actions. */

    for (ii = 0; ii < E_COMPOSER_NUM_HEADERS; ii++) {
        EComposerHeaderTable *table;
        EComposerHeader *header;
        GtkAction *action;

        table = E_COMPOSER_HEADER_TABLE (priv->header_table);
        header = e_composer_header_table_get_header (table, ii);

        switch (ii) {
            case E_COMPOSER_HEADER_BCC:
                action = ACTION (VIEW_BCC);
                break;

            case E_COMPOSER_HEADER_CC:
                action = ACTION (VIEW_CC);
                break;

            case E_COMPOSER_HEADER_REPLY_TO:
                action = ACTION (VIEW_REPLY_TO);
                break;

            default:
                continue;
        }

        g_object_bind_property (
            header, "sensitive",
            action, "sensitive",
            G_BINDING_BIDIRECTIONAL |
            G_BINDING_SYNC_CREATE);

        g_object_bind_property (
            header, "visible",
            action, "active",
            G_BINDING_BIDIRECTIONAL |
            G_BINDING_SYNC_CREATE);
    }

    /* Install a handler for inline images. */

    /* XXX We no longer use GtkhtmlEditor::uri-requested because it
     *     conflicts with EWebView's url_requested() method, which
     *     unconditionally launches an async operation.  I changed
     *     GtkHTML::url-requested to be a G_SIGNAL_RUN_LAST so that
     *     our handler runs first.  If we can handle the request
     *     we'll stop the signal emission to prevent EWebView from
     *     launching an async operation.  Messy, but works until we
     *     switch to WebKit.  --mbarnes */

    g_signal_connect (
        web_view, "url-requested",
        G_CALLBACK (msg_composer_url_requested_cb), composer);

    g_object_unref (settings);
}

void
e_composer_private_dispose (EMsgComposer *composer)
{
    if (composer->priv->shell != NULL) {
        g_object_remove_weak_pointer (
            G_OBJECT (composer->priv->shell),
            &composer->priv->shell);
        composer->priv->shell = NULL;
    }

    if (composer->priv->header_table != NULL) {
        g_object_unref (composer->priv->header_table);
        composer->priv->header_table = NULL;
    }

    if (composer->priv->activity_bar != NULL) {
        g_object_unref (composer->priv->activity_bar);
        composer->priv->activity_bar = NULL;
    }

    if (composer->priv->alert_bar != NULL) {
        g_object_unref (composer->priv->alert_bar);
        composer->priv->alert_bar = NULL;
    }

    if (composer->priv->attachment_paned != NULL) {
        g_object_unref (composer->priv->attachment_paned);
        composer->priv->attachment_paned = NULL;
    }

    if (composer->priv->focus_tracker != NULL) {
        g_object_unref (composer->priv->focus_tracker);
        composer->priv->focus_tracker = NULL;
    }

    if (composer->priv->window_group != NULL) {
        g_object_unref (composer->priv->window_group);
        composer->priv->window_group = NULL;
    }

    if (composer->priv->async_actions != NULL) {
        g_object_unref (composer->priv->async_actions);
        composer->priv->async_actions = NULL;
    }

    if (composer->priv->charset_actions != NULL) {
        g_object_unref (composer->priv->charset_actions);
        composer->priv->charset_actions = NULL;
    }

    if (composer->priv->composer_actions != NULL) {
        g_object_unref (composer->priv->composer_actions);
        composer->priv->composer_actions = NULL;
    }

    g_clear_object (&composer->priv->gallery_icon_view);
    g_clear_object (&composer->priv->gallery_scrolled_window);

    g_hash_table_remove_all (composer->priv->inline_images);
    g_hash_table_remove_all (composer->priv->inline_images_by_url);

    if (composer->priv->redirect != NULL) {
        g_object_unref (composer->priv->redirect);
        composer->priv->redirect = NULL;
    }
}

void
e_composer_private_finalize (EMsgComposer *composer)
{
    GPtrArray *array;

    array = composer->priv->extra_hdr_names;
    g_ptr_array_foreach (array, (GFunc) g_free, NULL);
    g_ptr_array_free (array, TRUE);

    array = composer->priv->extra_hdr_values;
    g_ptr_array_foreach (array, (GFunc) g_free, NULL);
    g_ptr_array_free (array, TRUE);

    g_free (composer->priv->charset);
    g_free (composer->priv->mime_type);
    g_free (composer->priv->mime_body);
    g_free (composer->priv->selected_signature_uid);

    g_hash_table_destroy (composer->priv->inline_images);
    g_hash_table_destroy (composer->priv->inline_images_by_url);
}

gchar *
e_composer_find_data_file (const gchar *basename)
{
    gchar *filename;

    g_return_val_if_fail (basename != NULL, NULL);

    /* Support running directly from the source tree. */
    filename = g_build_filename (".", basename, NULL);
    if (g_file_test (filename, G_FILE_TEST_EXISTS))
        return filename;
    g_free (filename);

    /* XXX This is kinda broken. */
    filename = g_build_filename (EVOLUTION_UIDIR, basename, NULL);
    if (g_file_test (filename, G_FILE_TEST_EXISTS))
        return filename;
    g_free (filename);

    g_critical ("Could not locate '%s'", basename);

    return NULL;
}

gchar *
e_composer_get_default_charset (void)
{
    GSettings *settings;
    gchar *charset;

    settings = g_settings_new ("org.gnome.evolution.mail");

    charset = g_settings_get_string (settings, "composer-charset");

    /* See what charset the mailer is using.
     * XXX We should not have to know where this lives in GSettings.
     *     Need a mail_config_get_default_charset() that does this. */
    if (!charset || charset[0] == '\0') {
        g_free (charset);
        charset = g_settings_get_string (settings, "charset");
        if (charset != NULL && *charset == '\0') {
            g_free (charset);
            charset = NULL;
        }
    }

    g_object_unref (settings);

    if (charset == NULL)
        charset = g_strdup (camel_iconv_locale_charset ());

    if (charset == NULL)
        charset = g_strdup ("us-ascii");

    return charset;
}

gchar *
e_composer_decode_clue_value (const gchar *encoded_value)
{
    GString *buffer;
    const gchar *cp;

    /* Decode a GtkHtml "ClueFlow" value. */

    g_return_val_if_fail (encoded_value != NULL, NULL);

    buffer = g_string_sized_new (strlen (encoded_value));

    /* Copy the value, decoding escaped characters as we go. */
    cp = encoded_value;
    while (*cp != '\0') {
        if (*cp == '.') {
            cp++;
            switch (*cp) {
                case '.':
                    g_string_append_c (buffer, '.');
                    break;
                case '1':
                    g_string_append_c (buffer, '"');
                    break;
                case '2':
                    g_string_append_c (buffer, '=');
                    break;
                default:
                    /* Invalid escape sequence. */
                    g_string_free (buffer, TRUE);
                    return NULL;
            }
        } else
            g_string_append_c (buffer, *cp);
        cp++;
    }

    return g_string_free (buffer, FALSE);
}

gchar *
e_composer_encode_clue_value (const gchar *decoded_value)
{
    gchar *encoded_value;
    gchar **strv;

    /* Encode a GtkHtml "ClueFlow" value. */

    g_return_val_if_fail (decoded_value != NULL, NULL);

    /* XXX This is inefficient but easy to understand. */

    encoded_value = g_strdup (decoded_value);

    /* Substitution: '.' --> '..' (do this first) */
    if (strchr (encoded_value, '.') != NULL) {
        strv = g_strsplit (encoded_value, ".", 0);
        g_free (encoded_value);
        encoded_value = g_strjoinv ("..", strv);
        g_strfreev (strv);
    }

    /* Substitution: '"' --> '.1' */
    if (strchr (encoded_value, '"') != NULL) {
        strv = g_strsplit (encoded_value, """", 0);
        g_free (encoded_value);
        encoded_value = g_strjoinv (".1", strv);
        g_strfreev (strv);
    }

    /* Substitution: '=' --> '.2' */
    if (strchr (encoded_value, '=') != NULL) {
        strv = g_strsplit (encoded_value, "=", 0);
        g_free (encoded_value);
        encoded_value = g_strjoinv (".2", strv);
        g_strfreev (strv);
    }

    return encoded_value;
}

gboolean
e_composer_paste_html (EMsgComposer *composer,
                       GtkClipboard *clipboard)
{
    GtkhtmlEditor *editor;
    gchar *html;

    g_return_val_if_fail (E_IS_MSG_COMPOSER (composer), FALSE);
    g_return_val_if_fail (GTK_IS_CLIPBOARD (clipboard), FALSE);

    html = e_clipboard_wait_for_html (clipboard);
    g_return_val_if_fail (html != NULL, FALSE);

    editor = GTKHTML_EDITOR (composer);
    gtkhtml_editor_insert_html (editor, html);

    g_free (html);

    return TRUE;
}

gboolean
e_composer_paste_image (EMsgComposer *composer,
                        GtkClipboard *clipboard)
{
    GtkhtmlEditor *editor;
    EAttachmentStore *store;
    EAttachmentView *view;
    GdkPixbuf *pixbuf = NULL;
    gchar *filename = NULL;
    gchar *uri = NULL;
    gboolean success = FALSE;
    GError *error = NULL;

    g_return_val_if_fail (E_IS_MSG_COMPOSER (composer), FALSE);
    g_return_val_if_fail (GTK_IS_CLIPBOARD (clipboard), FALSE);

    editor = GTKHTML_EDITOR (composer);
    view = e_msg_composer_get_attachment_view (composer);
    store = e_attachment_view_get_store (view);

    /* Extract the image data from the clipboard. */
    pixbuf = gtk_clipboard_wait_for_image (clipboard);
    g_return_val_if_fail (pixbuf != NULL, FALSE);

    /* Reserve a temporary file. */
    filename = e_mktemp (NULL);
    if (filename == NULL) {
        g_set_error (
            &error, G_FILE_ERROR,
            g_file_error_from_errno (errno),
            "Could not create temporary file: %s",
            g_strerror (errno));
        goto exit;
    }

    /* Save the pixbuf as a temporary file in image/png format. */
    if (!gdk_pixbuf_save (pixbuf, filename, "png", &error, NULL))
        goto exit;

    /* Convert the filename to a URI. */
    uri = g_filename_to_uri (filename, NULL, &error);
    if (uri == NULL)
        goto exit;

    /* In HTML mode, paste the image into the message body.
     * In text mode, add the image to the attachment store. */
    if (gtkhtml_editor_get_html_mode (editor))
        gtkhtml_editor_insert_image (editor, uri);
    else {
        EAttachment *attachment;

        attachment = e_attachment_new_for_uri (uri);
        e_attachment_store_add_attachment (store, attachment);
        e_attachment_load_async (
            attachment, (GAsyncReadyCallback)
            e_attachment_load_handle_error, composer);
        g_object_unref (attachment);
    }

    success = TRUE;

exit:
    if (error != NULL) {
        g_warning ("%s", error->message);
        g_error_free (error);
    }

    g_object_unref (pixbuf);
    g_free (filename);
    g_free (uri);

    return success;
}

gboolean
e_composer_paste_text (EMsgComposer *composer,
                       GtkClipboard *clipboard)
{
    GtkhtmlEditor *editor;
    gchar *text;

    g_return_val_if_fail (E_IS_MSG_COMPOSER (composer), FALSE);
    g_return_val_if_fail (GTK_IS_CLIPBOARD (clipboard), FALSE);

    text = gtk_clipboard_wait_for_text (clipboard);
    g_return_val_if_fail (text != NULL, FALSE);

    editor = GTKHTML_EDITOR (composer);
    gtkhtml_editor_insert_text (editor, text);

    g_free (text);

    return TRUE;
}

gboolean
e_composer_paste_uris (EMsgComposer *composer,
                       GtkClipboard *clipboard)
{
    EAttachmentStore *store;
    EAttachmentView *view;
    gchar **uris;
    gint ii;

    g_return_val_if_fail (E_IS_MSG_COMPOSER (composer), FALSE);
    g_return_val_if_fail (GTK_IS_CLIPBOARD (clipboard), FALSE);

    view = e_msg_composer_get_attachment_view (composer);
    store = e_attachment_view_get_store (view);

    /* Extract the URI data from the clipboard. */
    uris = gtk_clipboard_wait_for_uris (clipboard);
    g_return_val_if_fail (uris != NULL, FALSE);

    /* Add the URIs to the attachment store. */
    for (ii = 0; uris[ii] != NULL; ii++) {
        EAttachment *attachment;

        attachment = e_attachment_new_for_uri (uris[ii]);
        e_attachment_store_add_attachment (store, attachment);
        e_attachment_load_async (
            attachment, (GAsyncReadyCallback)
            e_attachment_load_handle_error, composer);
        g_object_unref (attachment);
    }

    return TRUE;
}

gboolean
e_composer_selection_is_image_uris (EMsgComposer *composer,
                                    GtkSelectionData *selection)
{
    gboolean all_image_uris = TRUE;
    gchar **uris;
    guint ii;

    g_return_val_if_fail (E_IS_MSG_COMPOSER (composer), FALSE);
    g_return_val_if_fail (selection != NULL, FALSE);

    uris = gtk_selection_data_get_uris (selection);

    if (uris == NULL)
        return FALSE;

    for (ii = 0; uris[ii] != NULL; ii++) {
        GFile *file;
        GFileInfo *file_info;
        GdkPixbufLoader *loader;
        const gchar *attribute;
        const gchar *content_type;
        gchar *mime_type = NULL;

        file = g_file_new_for_uri (uris[ii]);
        attribute = G_FILE_ATTRIBUTE_STANDARD_FAST_CONTENT_TYPE;

        /* XXX This blocks, but we're requesting the fast content
         *     type (which only inspects filenames), so hopefully
         *     it won't be noticeable.  Also, this is best effort
         *     so we don't really care if it fails. */
        file_info = g_file_query_info (
            file, attribute, G_FILE_QUERY_INFO_NONE, NULL, NULL);

        if (file_info == NULL) {
            g_object_unref (file);
            all_image_uris = FALSE;
            break;
        }

        content_type = g_file_info_get_attribute_string (
            file_info, attribute);
        mime_type = g_content_type_get_mime_type (content_type);

        g_object_unref (file_info);
        g_object_unref (file);

        if (mime_type == NULL) {
            all_image_uris = FALSE;
            break;
        }

        /* Easy way to determine if a MIME type is a supported
         * image format: try creating a GdkPixbufLoader for it. */
        loader = gdk_pixbuf_loader_new_with_mime_type (mime_type, NULL);

        g_free (mime_type);

        if (loader == NULL) {
            all_image_uris = FALSE;
            break;
        }

        gdk_pixbuf_loader_close (loader, NULL);
        g_object_unref (loader);
    }

    g_strfreev (uris);

    return all_image_uris;
}

static gboolean
add_signature_delimiter (EMsgComposer *composer)
{
    GSettings *settings;
    gboolean signature_delim;

    /* FIXME This should be an EMsgComposer property. */
    settings = g_settings_new ("org.gnome.evolution.mail");
    signature_delim = !g_settings_get_boolean (
        settings, "composer-no-signature-delim");
    g_object_unref (settings);

    return signature_delim;
}

static gboolean
use_top_signature (EMsgComposer *composer)
{
    GSettings *settings;
    gboolean top_signature;

    /* FIXME This should be an EMsgComposer property. */
    settings = g_settings_new ("org.gnome.evolution.mail");
    top_signature = g_settings_get_boolean (
        settings, "composer-top-signature");
    g_object_unref (settings);

    return top_signature;
}

static void
composer_load_signature_cb (EMailSignatureComboBox *combo_box,
                            GAsyncResult *result,
                            EMsgComposer *composer)
{
    GString *html_buffer = NULL;
    GtkhtmlEditor *editor;
    gchar *contents = NULL;
    gsize length = 0;
    const gchar *active_id;
    gchar *encoded_uid = NULL;
    gboolean top_signature;
    gboolean is_html;
    GError *error = NULL;

    e_mail_signature_combo_box_load_selected_finish (
        combo_box, result, &contents, &length, &is_html, &error);

    /* FIXME Use an EAlert here. */
    if (error != NULL) {
        g_warning ("%s: %s", G_STRFUNC, error->message);
        g_error_free (error);
        goto exit;
    }

    /* "Edit as New Message" sets "priv->is_from_message".
     * Always put the signature at the bottom for that case. */
    top_signature =
        use_top_signature (composer) &&
        !composer->priv->is_from_message;

    if (contents == NULL)
        goto insert;

    if (!is_html) {
        gchar *html;

        html = camel_text_to_html (contents, 0, 0);
        if (html) {
            g_free (contents);

            contents = html;
            length = strlen (contents);
        }
    }

    /* Generate HTML code for the signature. */

    html_buffer = g_string_sized_new (1024);

    /* The combo box active ID is the signature's ESource UID. */
    active_id = gtk_combo_box_get_active_id (GTK_COMBO_BOX (combo_box));

    if (active_id != NULL && *active_id != '\0')
        encoded_uid = e_composer_encode_clue_value (active_id);

    g_string_append_printf (
        html_buffer,
        "<!--+GtkHTML:<DATA class=\"ClueFlow\" "
        "    key=\"signature\" value=\"1\">-->"
        "<!--+GtkHTML:<DATA class=\"ClueFlow\" "
        "    key=\"signature_name\" value=\"uid:%s\">-->",
        (encoded_uid != NULL) ? encoded_uid : "");

    g_string_append (
        html_buffer,
        "<TABLE WIDTH=\"100%%\" CELLSPACING=\"0\""
        " CELLPADDING=\"0\"><TR><TD>");

    if (!is_html)
        g_string_append (html_buffer, "<PRE>\n");

    /* The signature dash convention ("-- \n") is specified
     * in the "Son of RFC 1036", section 4.3.2.
     * http://www.chemie.fu-berlin.de/outerspace/netnews/son-of-1036.html
     */
    if (add_signature_delimiter (composer)) {
        const gchar *delim;
        const gchar *delim_nl;

        if (is_html) {
            delim = "-- \n<BR>";
            delim_nl = "\n-- \n<BR>";
        } else {
            delim = "-- \n";
            delim_nl = "\n-- \n";
        }

        /* Skip the delimiter if the signature already has one. */
        if (g_ascii_strncasecmp (contents, delim, strlen (delim)) == 0)
            ;  /* skip */
        else if (e_util_strstrcase (contents, delim_nl) != NULL)
            ;  /* skip */
        else
            g_string_append (html_buffer, delim);
    }

    g_string_append_len (html_buffer, contents, length);

    if (!is_html)
        g_string_append (html_buffer, "</PRE>\n");

    if (top_signature)
        g_string_append (html_buffer, "<BR>");

    g_string_append (html_buffer, "</TD></TR></TABLE>");

    g_free (encoded_uid);
    g_free (contents);

insert:
    /* Remove the old signature and insert the new one. */

    editor = GTKHTML_EDITOR (composer);

    /* This prevents our command before/after callbacks from
     * screwing around with the signature as we insert it. */
    composer->priv->in_signature_insert = TRUE;

    gtkhtml_editor_freeze (editor);
    gtkhtml_editor_run_command (editor, "cursor-position-save");
    gtkhtml_editor_undo_begin (editor, "Set signature", "Reset signature");

    gtkhtml_editor_run_command (editor, "block-selection");
    gtkhtml_editor_run_command (editor, "cursor-bod");
    if (gtkhtml_editor_search_by_data (editor, 1, "ClueFlow", "signature", "1")) {
        gtkhtml_editor_run_command (editor, "select-paragraph");
        gtkhtml_editor_run_command (editor, "delete");
        gtkhtml_editor_set_paragraph_data (editor, "signature", "0");
        gtkhtml_editor_run_command (editor, "delete-back");
    }
    gtkhtml_editor_run_command (editor, "unblock-selection");

    if (html_buffer != NULL) {
        gtkhtml_editor_run_command (editor, "insert-paragraph");
        if (!gtkhtml_editor_run_command (editor, "cursor-backward"))
            gtkhtml_editor_run_command (editor, "insert-paragraph");
        else
            gtkhtml_editor_run_command (editor, "cursor-forward");

        gtkhtml_editor_set_paragraph_data (editor, "orig", "0");
        gtkhtml_editor_run_command (editor, "indent-zero");
        gtkhtml_editor_run_command (editor, "style-normal");
        gtkhtml_editor_insert_html (editor, html_buffer->str);

        g_string_free (html_buffer, TRUE);

    } else if (top_signature) {
        /* Insert paragraph after the signature ClueFlow stuff. */
        if (gtkhtml_editor_run_command (editor, "cursor-forward"))
            gtkhtml_editor_run_command (editor, "insert-paragraph");
    }

    gtkhtml_editor_undo_end (editor);
    gtkhtml_editor_run_command (editor, "cursor-position-restore");
    gtkhtml_editor_thaw (editor);

    composer->priv->in_signature_insert = FALSE;

exit:
    g_object_unref (composer);
}

static gboolean
is_null_or_none (const gchar *text)
{
    return !text || g_strcmp0 (text, "none") == 0;
}

void
e_composer_update_signature (EMsgComposer *composer)
{
    EComposerHeaderTable *table;
    EMailSignatureComboBox *combo_box;
    const gchar *signature_uid;

    g_return_if_fail (E_IS_MSG_COMPOSER (composer));

    /* Do nothing if we're redirecting a message. */
    if (composer->priv->redirect)
        return;

    table = e_msg_composer_get_header_table (composer);
    signature_uid = e_composer_header_table_get_signature_uid (table);

    /* this is a case when the signature combo cleared itself for a reload */
    if (!signature_uid)
        return;

    if (g_strcmp0 (signature_uid, composer->priv->selected_signature_uid) == 0 ||
        (is_null_or_none (signature_uid) && is_null_or_none (composer->priv->selected_signature_uid)))
        return;

    g_free (composer->priv->selected_signature_uid);
    composer->priv->selected_signature_uid = g_strdup (signature_uid);

    combo_box = e_composer_header_table_get_signature_combo_box (table);

    /* XXX Signature files should be local and therefore load quickly,
     *     so while we do load them asynchronously we don't allow for
     *     user cancellation and we keep the composer alive until the
     *     asynchronous loading is complete. */
    e_mail_signature_combo_box_load_selected (
        combo_box, G_PRIORITY_DEFAULT, NULL,
        (GAsyncReadyCallback) composer_load_signature_cb,
        g_object_ref (composer));
}