path: root/e-util/e-config.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 <stdlib.h>

#include <gtk/gtk.h>
#include <glib/gi18n.h>

#include "e-config.h"

#include <glib/gi18n.h>

#define d(x)

typedef GtkWidget *
        (*EConfigItemSectionFactoryFunc)
                        (EConfig *ec,
                         EConfigItem *item,
                         GtkWidget *parent,
                         GtkWidget *old,
                         gint position,
                         gpointer data,
                         GtkWidget **real_frame);

struct _EConfigFactory {
    gchar *id;
    EConfigFactoryFunc func;
    gpointer user_data;
};

struct _menu_node {
    GSList *menu;
    EConfigItemsFunc free;
    gpointer data;
};

struct _widget_node {
    EConfig *config;

    struct _menu_node *context;
    EConfigItem *item;
    GtkWidget *widget; /* widget created by the factory, if any */
    GtkWidget *frame; /* if created by us */
    GtkWidget *real_frame; /* used for sections and section tables, this is the real GtkFrame (whereas "frame" above is the internal vbox/table) */

    guint empty:1;      /* set if empty (i.e. hidden) */
};

struct _check_node {
    gchar *pageid;
    EConfigCheckFunc check;
    gpointer data;
};

struct _finish_page_node {
    gchar *pageid;
    gboolean is_finish;
    gint orig_type;
};

struct _EConfigPrivate {
    GList *menus;
    GList *widgets;
    GList *checks;
    GList *finish_pages;
};

static GtkWidget *
        ech_config_section_factory  (EConfig *config,
                         EConfigItem *item,
                         GtkWidget *parent,
                         GtkWidget *old,
                         gint position,
                         gpointer data,
                         GtkWidget **real_frame);

enum {
    ABORT,
    COMMIT,
    LAST_SIGNAL
};

static guint signals[LAST_SIGNAL];

G_DEFINE_TYPE (
    EConfig,
    e_config,
    G_TYPE_OBJECT)

static void
config_finalize (GObject *object)
{
    EConfig *emp = (EConfig *) object;
    EConfigPrivate *p = emp->priv;
    GList *link;

    d(printf("finalising EConfig %p\n", object));

    g_free (emp->id);

    link = p->menus;
    while (link != NULL) {
        struct _menu_node *node = link->data;

        if (node->free)
            node->free (emp, node->menu, node->data);

        g_free (node);

        link = g_list_delete_link (link, link);
    }

    link = p->widgets;
    while (link != NULL) {
        struct _widget_node *node = link->data;

        /* disconnect the ec_widget_destroyed function from the widget */
        if (node->widget)
            g_signal_handlers_disconnect_matched (
                node->widget, G_SIGNAL_MATCH_DATA,
                0, 0, NULL, NULL, node);

        g_free (node);

        link = g_list_delete_link (link, link);
    }

    link = p->checks;
    while (link != NULL) {
        struct _check_node *node = link->data;

        g_free (node->pageid);
        g_free (node);

        link = g_list_delete_link (link, link);
    }

    link = p->finish_pages;
    while (link != NULL) {
        struct _finish_page_node *node = link->data;

        g_free (node->pageid);
        g_free (node);

        link = g_list_delete_link (link, link);
    }

    /* Chain up to parent's finalize() method. */
    G_OBJECT_CLASS (e_config_parent_class)->finalize (object);
}

static void
config_target_free (EConfig *config,
                    EConfigTarget *target)
{
    g_free (target);
    g_object_unref (config);
}

static void
config_set_target (EConfig *config,
                   EConfigTarget *target)
{
    if (config->target != NULL)
        e_config_target_free (config, target);

    config->target = target;
}

static void
e_config_class_init (EConfigClass *class)
{
    GObjectClass *object_class;

    g_type_class_add_private (class, sizeof (EConfigPrivate));

    object_class = G_OBJECT_CLASS (class);
    object_class->finalize = config_finalize;

    class->set_target = config_set_target;
    class->target_free = config_target_free;

    signals[ABORT] = g_signal_new (
        "abort",
        G_OBJECT_CLASS_TYPE (object_class),
        G_SIGNAL_RUN_LAST,
        G_STRUCT_OFFSET (EConfigClass, abort),
        NULL, NULL,
        g_cclosure_marshal_VOID__VOID,
        G_TYPE_NONE, 0);

    signals[COMMIT] = g_signal_new (
        "commit",
        G_OBJECT_CLASS_TYPE (object_class),
        G_SIGNAL_RUN_LAST,
        G_STRUCT_OFFSET (EConfigClass, commit),
        NULL, NULL,
        g_cclosure_marshal_VOID__VOID,
        G_TYPE_NONE, 0);
}

static void
e_config_init (EConfig *config)
{
    config->priv = G_TYPE_INSTANCE_GET_PRIVATE (
        config, E_TYPE_CONFIG, EConfigPrivate);
}

/**
 * e_config_construct:
 * @ep: The instance to initialise.
 * @type: The type of configuration manager, @E_CONFIG_BOOK or
 * @E_CONFIG_ASSISTANT.
 * @id: The name of the configuration window this manager drives.
 *
 * Used by implementing classes to initialise base parameters.
 *
 * Return value: @ep is returned.
 **/
EConfig *
e_config_construct (EConfig *ep,
                    gint type,
                    const gchar *id)
{
    g_return_val_if_fail (type == E_CONFIG_BOOK || type == E_CONFIG_ASSISTANT, NULL);

    ep->type = type;
    ep->id = g_strdup (id);

    return ep;
}

/**
 * e_config_add_items:
 * @ec: An initialised implementing instance of EConfig.
 * @items: A list of EConfigItem's to add to the configuration manager
 * @ec.
 * @freefunc: If supplied, called to free the item list (and/or items)
 * once they are no longer needed.
 * @data: Data for the callback methods.
 *
 * Add new EConfigItems to the configuration window.  Nothing will be
 * done with them until the widget is built.
 *
 * TODO: perhaps commit and abort should just be signals.
 **/
void
e_config_add_items (EConfig *ec,
                    GSList *items,
                    EConfigItemsFunc freefunc,
                    gpointer data)
{
    struct _menu_node *node;

    node = g_malloc (sizeof (*node));
    node->menu = items;
    node->free = freefunc;
    node->data = data;

    ec->priv->menus = g_list_append (ec->priv->menus, node);
}

/**
 * e_config_add_page_check:
 * @ec: Initialised implemeting instance of EConfig.
 * @pageid: pageid to check.
 * @check: checking callback.
 * @data: user-data for the callback.
 *
 * Add a page-checking function callback.  It will be called to validate the
 * data in the given page or pages.  If @pageid is NULL then it will be called
 * to validate every page, or the whole configuration window.
 *
 * In the latter case, the pageid in the callback will be either the
 * specific page being checked, or NULL when the whole config window
 * is being checked.
 *
 * The page check function is used to validate input before allowing
 * the assistant to continue or the notebook to close.
 **/
void
e_config_add_page_check (EConfig *ec,
                         const gchar *pageid,
                         EConfigCheckFunc check,
                         gpointer data)
{
    struct _check_node *cn;

    cn = g_malloc0 (sizeof (*cn));
    cn->pageid = g_strdup (pageid);
    cn->check = check;
    cn->data = data;

    ec->priv->checks = g_list_append (ec->priv->checks, cn);
}

static struct _finish_page_node *
find_page_finish (EConfig *config,
                  const gchar *pageid)
{
    GList *link;

    link = config->priv->finish_pages;

    while (link != NULL) {
        struct _finish_page_node *node = link->data;

        if (g_str_equal (node->pageid, pageid))
            return node;

        link = g_list_next (link);
    }

    return NULL;
}

/**
 * e_config_set_page_is_finish:
 * @ec: Initialised implementing instance of EConfig.
 * @pageid: pageid to change the value on.
 * @can_finish: whether the pageid can finish immediately or not.
 *
 * With is_finish set on the pageid the page is treated as the last page in an assistant.
 **/
void
e_config_set_page_is_finish (EConfig *ec,
                             const gchar *pageid,
                             gboolean is_finish)
{
    struct _finish_page_node *fp;

    fp = find_page_finish (ec, pageid);

    if (is_finish) {
        if (!fp) {
            fp = g_malloc0 (sizeof (*fp));
            fp->pageid = g_strdup (pageid);
            ec->priv->finish_pages = g_list_append (
                ec->priv->finish_pages, fp);
        }

        fp->is_finish = TRUE;
    } else {
        if (fp)
            fp->is_finish = FALSE;
    }
}

static void
ec_add_static_items (EConfig *config)
{
    EConfigClass *class;
    GList *link;

    class = E_CONFIG_GET_CLASS (config);
    for (link = class->factories; link != NULL; link = link->next) {
        EConfigFactory *factory = link->data;

        if (factory->id == NULL || strcmp (factory->id, config->id) == 0)
            factory->func (config, factory->user_data);
    }
}

static gint
ep_cmp (gconstpointer ap,
        gconstpointer bp)
{
    struct _widget_node *a = *((gpointer *) ap);
    struct _widget_node *b = *((gpointer *) bp);

    return strcmp (a->item->path, b->item->path);
}

static GList *
ec_assistant_find_page (EConfig *ec,
                        GtkWidget *page,
                        gint *page_index)
{
    struct _widget_node *node = NULL;
    GList *link;

    g_return_val_if_fail (ec != NULL, NULL);
    g_return_val_if_fail (GTK_IS_ASSISTANT (ec->widget), NULL);
    g_return_val_if_fail (page != NULL, NULL);

    /* Assume failure, then if we do fail we can just return. */
    if (page_index != NULL)
        *page_index = -1;

    /* Find the page widget in our sorted widget node list. */
    for (link = ec->priv->widgets; link != NULL; link = link->next) {
        node = link->data;

        if (node->frame != page)
            continue;

        if (node->item->type == E_CONFIG_PAGE)
            break;

        if (node->item->type == E_CONFIG_PAGE_START)
            break;

        if (node->item->type == E_CONFIG_PAGE_FINISH)
            break;

        if (node->item->type == E_CONFIG_PAGE_PROGRESS)
            break;
    }

    /* FAIL: The widget is not in our list. */
    if (link == NULL)
        return NULL;

    /* Find the corresponding GtkAssistant page index. */
    if (page_index) {
        GtkAssistant *assistant;
        GtkWidget *nth_page;
        gint ii, n_pages;

        assistant = GTK_ASSISTANT (ec->widget);
        n_pages = gtk_assistant_get_n_pages (assistant);

        for (ii = 0; ii < n_pages; ii++) {
            nth_page = gtk_assistant_get_nth_page (assistant, ii);
            if (page == nth_page) {
                *page_index = ii;
                break;
            }
        }

        g_warn_if_fail (ii < n_pages);
    }

    return link;
}

static void
ec_assistant_check_current (EConfig *ec)
{
    struct _widget_node *wn;
    struct _finish_page_node *fp;
    GtkAssistant *assistant;
    GtkWidget *page;
    GList *link;
    gint page_no;

    g_return_if_fail (GTK_IS_ASSISTANT (ec->widget));

    assistant = GTK_ASSISTANT (ec->widget);
    page_no = gtk_assistant_get_current_page (assistant);

    /* no page selected yet */
    if (page_no == -1)
        return;

    page = gtk_assistant_get_nth_page (assistant, page_no);
    g_return_if_fail (page != NULL);

    link = ec_assistant_find_page (ec, page, NULL);
    g_return_if_fail (link != NULL);
    wn = link->data;

    /* this should come first, as the check function can change the finish state of the page */
    gtk_assistant_set_page_complete (assistant, page, e_config_page_check (ec, wn->item->path));

    fp = find_page_finish (ec, wn->item->path);
    if (fp) {
        GtkAssistantPageType pt = gtk_assistant_get_page_type (assistant, page);

        if (fp->is_finish && pt != GTK_ASSISTANT_PAGE_CONFIRM) {
            if (fp->orig_type == GTK_ASSISTANT_PAGE_CONTENT)
                fp->orig_type = pt;
            gtk_assistant_set_page_type (assistant, page, GTK_ASSISTANT_PAGE_CONFIRM);
        } else if (!fp->is_finish && pt != fp->orig_type) {
            gtk_assistant_set_page_type (assistant, page, fp->orig_type);
        }
    }

    gtk_assistant_update_buttons_state (assistant);
}

static gint
ec_assistant_forward (gint current_page,
                      gpointer user_data)
{
    GtkAssistant *assistant;
    EConfig *ec = user_data;
    struct _widget_node *node;
    GtkWidget *page_widget;
    GList *link = NULL;
    gint next_page;

    /* As far as we're concerned, the GtkAssistant is just an unordered
     * collection of pages.  Our sorted list of widget nodes determines
     * the next page. */

    assistant = GTK_ASSISTANT (ec->widget);
    page_widget = gtk_assistant_get_nth_page (assistant, current_page);
    link = ec_assistant_find_page (ec, page_widget, NULL);

    g_return_val_if_fail (link != NULL, -1);
    node = (struct _widget_node *) link->data;

    /* If we're already on a FINISH page then we're done. */
    if (node->item->type == E_CONFIG_PAGE_FINISH)
        return -1;

    /* Find the next E_CONFIG_PAGE* type node. */
    for (link = link->next; link != NULL; link = link->next) {
        node = (struct _widget_node *) link->data;

        if (node->empty || node->frame == NULL)
            continue;

        if (node->item->type == E_CONFIG_PAGE)
            break;

        if (node->item->type == E_CONFIG_PAGE_START)
            break;

        if (node->item->type == E_CONFIG_PAGE_FINISH)
            break;

        if (node->item->type == E_CONFIG_PAGE_PROGRESS)
            break;
    }

    /* Find the corresponding GtkAssistant page number. */
    if (link != NULL) {
        node = (struct _widget_node *) link->data;
        ec_assistant_find_page (ec, node->frame, &next_page);
    } else
        next_page = -1;

    return next_page;
}

static void
ec_widget_destroyed (GtkWidget *widget,
                     struct _widget_node *node)
{
    /* Use our own function instead of gtk_widget_destroyed()
     * so it's easier to trap EConfig widgets in a debugger. */

    node->widget = NULL;
}

static void
ec_rebuild (EConfig *emp)
{
    EConfigPrivate *p = emp->priv;
    struct _widget_node *sectionnode = NULL, *pagenode = NULL;
    GtkWidget *book = NULL, *page = NULL, *section = NULL, *root = NULL, *assistant = NULL;
    gint pageno = 0, sectionno = 0, itemno = 0;
    gint n_visible_widgets = 0;
    GList *last_active_link = NULL;
    gboolean is_assistant;
    GList *link;

    d(printf("target changed, rebuilding:\n"));

    /* TODO: This code is pretty complex, and will probably just
     * become more complex with time.  It could possibly be split
     * into the two base types, but there would be a lot of code
     * duplication */

    /* because rebuild destroys pages, and destroying active page causes crashes */
    is_assistant = GTK_IS_ASSISTANT (emp->widget);
    if (is_assistant) {
        GtkAssistant *assistant;
        gint page_index;

        assistant = GTK_ASSISTANT (emp->widget);
        page_index = gtk_assistant_get_current_page (assistant);

        if (page_index != -1) {
            GtkWidget *nth_page;

            nth_page = gtk_assistant_get_nth_page (
                GTK_ASSISTANT (emp->widget), page_index);
            last_active_link = ec_assistant_find_page (
                emp, nth_page, NULL);
        }
        gtk_assistant_set_current_page (GTK_ASSISTANT (emp->widget), 0);
    }

    for (link = p->widgets; link != NULL; link = g_list_next (link)) {
        struct _widget_node *wn = link->data;
        struct _EConfigItem *item = wn->item;
        const gchar *translated_label = NULL;
        GtkWidget *w;

        d(printf(" '%s'\n", item->path));

        if (item->label != NULL)
            translated_label = gettext (item->label);

        /* If the last section doesn't contain any visible widgets, hide it */
        if (sectionnode != NULL
            && sectionnode->frame != NULL
            && (item->type == E_CONFIG_PAGE
            || item->type == E_CONFIG_PAGE_START
            || item->type == E_CONFIG_PAGE_FINISH
            || item->type == E_CONFIG_PAGE_PROGRESS
            || item->type == E_CONFIG_SECTION
            || item->type == E_CONFIG_SECTION_TABLE)) {
            if ((sectionnode->empty = (itemno == 0 || n_visible_widgets == 0))) {
                if (sectionnode->real_frame)
                    gtk_widget_hide (sectionnode->real_frame);

                if (sectionnode->frame)
                    gtk_widget_hide (sectionnode->frame);

                sectionno--;
            } else {
                if (sectionnode->real_frame)
                    gtk_widget_show (sectionnode->real_frame);

                if (sectionnode->frame)
                    gtk_widget_show (sectionnode->frame);
            }

            d(printf("%s section '%s' [sections=%d]\n", sectionnode->empty?"hiding":"showing", sectionnode->item->path, sectionno));
        }

        /* If the last page doesn't contain anything, hide it */
        if (pagenode != NULL
            && pagenode->frame != NULL
            && (item->type == E_CONFIG_PAGE
            || item->type == E_CONFIG_PAGE_START
            || item->type == E_CONFIG_PAGE_FINISH
            || item->type == E_CONFIG_PAGE_PROGRESS)) {
            if ((pagenode->empty = sectionno == 0)) {
                gtk_widget_hide (pagenode->frame);
                pageno--;
            } else
                gtk_widget_show (pagenode->frame);
            d(printf("%s page '%s' [section=%d]\n", pagenode->empty?"hiding":"showing", pagenode->item->path, pageno));
        }

        /* Now process the item */
        switch (item->type) {
        case E_CONFIG_BOOK:
        case E_CONFIG_ASSISTANT:
            /* Only one of BOOK or ASSISTANT may be define, it
             * is used by the defining code to mark the
             * type of the config window.  It is
             * cross-checked with the code's defined
             * type. */
            if (root != NULL) {
                g_warning("EConfig book/assistant redefined at: %s", item->path);
                break;
            }

            if (wn->widget == NULL) {
                if (item->type != emp->type) {
                    g_warning("EConfig book/assistant type mismatch");
                    break;
                }
                if (item->factory) {
                    root = item->factory (
                        emp, item, NULL, wn->widget,
                        0, wn->context->data);
                } else if (item->type == E_CONFIG_BOOK) {
                    root = gtk_notebook_new ();
                    gtk_widget_show (root);
                } else if (item->type == E_CONFIG_ASSISTANT) {
                    root = gtk_assistant_new ();
                } else
                    abort ();

                if (item->type == E_CONFIG_ASSISTANT) {
                    g_signal_connect_swapped (
                        root, "apply",
                        G_CALLBACK (e_config_commit), emp);
                    g_signal_connect_swapped (
                        root, "cancel",
                        G_CALLBACK (e_config_abort), emp);
                    g_signal_connect (
                        root, "cancel",
                        G_CALLBACK (gtk_widget_destroy), emp);
                    g_signal_connect (
                        root, "close",
                        G_CALLBACK (gtk_widget_destroy), NULL);
                    g_signal_connect_swapped (
                        root, "prepare",
                        G_CALLBACK (ec_assistant_check_current), emp);
                    gtk_assistant_set_forward_page_func (
                        GTK_ASSISTANT (root),
                        ec_assistant_forward, emp, NULL);
                }

                emp->widget = root;
                wn->widget = root;
            } else {
                root = wn->widget;
            }

            if (item->type == E_CONFIG_BOOK)
                book = root;
            else
                assistant = root;

            page = NULL;
            pagenode = NULL;
            section = NULL;
            sectionnode = NULL;
            pageno = 0;
            sectionno = 0;
            break;
        case E_CONFIG_PAGE_START:
        case E_CONFIG_PAGE_FINISH:
            if (root == NULL) {
                g_warning("EConfig page defined before container widget: %s", item->path);
                break;
            }
            if (emp->type != E_CONFIG_ASSISTANT) {
                g_warning("EConfig assistant start/finish pages can't be used on E_CONFIG_BOOKs");
                break;
            }

            if (wn->widget == NULL) {
                if (item->factory) {
                    page = item->factory (
                        emp, item, root, wn->frame,
                        pageno, wn->context->data);
                } else {
                    page = gtk_vbox_new (FALSE, 0);
                    gtk_container_set_border_width (GTK_CONTAINER (page), 12);
                    if (pagenode) {
                        /* put after */
                        gint index = -1;
                        ec_assistant_find_page (emp, pagenode->frame, &index);
                        gtk_assistant_insert_page (GTK_ASSISTANT (assistant), page, index + 1);
                    } else {
                        gtk_assistant_prepend_page (GTK_ASSISTANT (assistant), page);
                    }

                    gtk_assistant_set_page_type (GTK_ASSISTANT (assistant), page, item->type == E_CONFIG_PAGE_START ? GTK_ASSISTANT_PAGE_INTRO : GTK_ASSISTANT_PAGE_CONFIRM);
                    gtk_assistant_set_page_title (GTK_ASSISTANT (assistant), page, translated_label);
                    gtk_widget_show_all (page);
                }

                if (wn->widget != NULL && wn->widget != page) {
                    gtk_widget_destroy (wn->widget);
                }

                wn->frame = page;
                wn->widget = page;

                if (page) {
                    const gchar *empty_xpm_img[] = {
                        "75 1 2 1",
                        "   c None",
                        ".  c #FFFFFF",
                        "                                                                           "};

                    /* left side place with a blue background on a start and finish page */
                    GdkPixbuf *spacer = gdk_pixbuf_new_from_xpm_data (empty_xpm_img);

                    gtk_assistant_set_page_side_image (GTK_ASSISTANT (assistant), page, spacer);

                    g_object_unref (spacer);
                }
            }

            pageno++;
            page = NULL;
            pagenode = wn; /* need this for previous page linking */
            section = NULL;
            sectionnode = NULL;
            sectionno = 1; /* never want to hide these */
            break;
        case E_CONFIG_PAGE:
        case E_CONFIG_PAGE_PROGRESS:
            /* CONFIG_PAGEs depend on the config type.
             * E_CONFIG_BOOK:
                The page is a VBox, stored in the notebook.
             * E_CONFIG_ASSISTANT
                The page is a VBox, stored in the GtkAssistant,
                any sections automatically added inside it. */
            sectionno = 0;
            if (root == NULL) {
                g_warning("EConfig page defined before container widget: %s", item->path);
                break;
            }
            if (item->type == E_CONFIG_PAGE_PROGRESS &&
                emp->type != E_CONFIG_ASSISTANT) {
                g_warning("EConfig assistant progress pages can't be used on E_CONFIG_BOOKs");
                break;
            }

            if (item->factory) {
                page = item->factory (
                    emp, item, root, wn->frame,
                    pageno, wn->context->data);
                if (emp->type == E_CONFIG_ASSISTANT) {
                    wn->frame = page;
                } else {
                    wn->frame = page;
                    if (page)
                        gtk_notebook_reorder_child ((GtkNotebook *) book, page, pageno);
                }
                if (page)
                    sectionno = 1;
            } else if (wn->widget == NULL) {
                if (emp->type == E_CONFIG_ASSISTANT) {
                    page = gtk_vbox_new (FALSE, 0);
                    gtk_container_set_border_width (GTK_CONTAINER (page), 12);
                    if (pagenode) {
                        /* put after */
                        gint index = -1;
                        ec_assistant_find_page (emp, pagenode->frame, &index);
                        gtk_assistant_insert_page (GTK_ASSISTANT (assistant), page, index + 1);
                    } else {
                        gtk_assistant_prepend_page (GTK_ASSISTANT (assistant), page);
                    }

                    gtk_assistant_set_page_type (GTK_ASSISTANT (assistant), page, item->type == E_CONFIG_PAGE ? GTK_ASSISTANT_PAGE_CONTENT : GTK_ASSISTANT_PAGE_PROGRESS);
                    gtk_assistant_set_page_title (GTK_ASSISTANT (assistant), page, translated_label);
                    gtk_widget_show_all (page);

                    wn->frame = page;
                } else {
                    w = gtk_label_new_with_mnemonic (translated_label);
                    gtk_widget_show (w);
                    page = gtk_vbox_new (FALSE, 12);
                    gtk_container_set_border_width ((GtkContainer *) page, 12);
                    gtk_widget_show (page);
                    gtk_notebook_insert_page ((GtkNotebook *) book, page, w, pageno);
                    gtk_container_child_set (GTK_CONTAINER (book), page, "tab-fill", FALSE, "tab-expand", FALSE, NULL);
                    wn->frame = page;
                }
            } else
                page = wn->widget;

            d(printf("page %d:%s widget %p\n", pageno, item->path, page));

            if (wn->widget && wn->widget != page) {
                d(printf("destroy old widget for page '%s' (%p)\n", item->path, wn->widget));
                gtk_widget_destroy (wn->widget);
            }

            pageno++;
            pagenode = wn;
            section = NULL;
            sectionnode = NULL;
            wn->widget = page;
            if (page)
                g_signal_connect (
                    page, "destroy",
                    G_CALLBACK (ec_widget_destroyed), wn);
            break;
        case E_CONFIG_SECTION:
        case E_CONFIG_SECTION_TABLE:
            /* The section factory is always called with
             * the parent vbox object.  Even for assistant pages. */
            if (page == NULL) {
                /*g_warning("EConfig section '%s' has no parent page", item->path);*/
                section = NULL;
                wn->widget = NULL;
                wn->frame = NULL;
                goto nopage;
            }

            itemno = 0;
            n_visible_widgets = 0;

            d(printf("Building section %s - '%s' - %s factory\n", item->path, item->label, item->factory ? "with" : "without"));

            if (item->factory) {
                /* For sections, we pass an extra argument to the usual EConfigItemFactoryFunc.
                 * If this is an automatically-generated section, that extra argument (real_frame from
                 * EConfigItemSectionFactoryFunc) will contain the actual GtkFrame upon returning.
                 */
                EConfigItemSectionFactoryFunc factory = (EConfigItemSectionFactoryFunc) item->factory;

                section = factory (
                    emp, item, page, wn->widget, 0,
                    wn->context->data, &wn->real_frame);
                wn->frame = section;
                if (section)
                    itemno = 1;

                if (factory != ech_config_section_factory) {
                    /* This means there is a section that came from a user-specified factory,
                     * so we don't know what is inside the section.  In that case, we increment
                     * n_visible_widgets so that the section will not get hidden later (we don't know
                     * if the section is empty or not, so we cannot decide to hide it).
                     *
                     * For automatically-generated sections, we use a special ech_config_section_factory() -
                     * see emph_construct_item().
                     */
                    n_visible_widgets++;
                    d(printf ("  n_visible_widgets++ because there is a section factory -> frame=%p\n", section));
                }

                if (section
                    && ((item->type == E_CONFIG_SECTION && !GTK_IS_BOX (section))
                    || (item->type == E_CONFIG_SECTION_TABLE && !GTK_IS_TABLE (section))))
                    g_warning("EConfig section type is wrong");
            } else {
                GtkWidget *frame;
                GtkWidget *label = NULL;

                if (wn->frame) {
                    d(printf("Item %s, clearing generated section widget\n", wn->item->path));
                    gtk_widget_destroy (wn->frame);
                    wn->widget = NULL;
                    wn->frame = NULL;
                }

                if (translated_label != NULL) {
                    gchar *txt = g_markup_printf_escaped("<span weight=\"bold\">%s</span>", translated_label);

                    label = g_object_new (gtk_label_get_type (),
                                 "label", txt,
                                 "use_markup", TRUE,
                                 "xalign", 0.0, NULL);
                    g_free (txt);
                }

                if (item->type == E_CONFIG_SECTION)
                    section = gtk_vbox_new (FALSE, 6);
                else {
                    section = gtk_table_new (1, 1, FALSE);
                    gtk_table_set_col_spacings ((GtkTable *) section, 6);
                    gtk_table_set_row_spacings ((GtkTable *) section, 6);
                }

                frame = g_object_new (gtk_frame_get_type (),
                             "shadow_type", GTK_SHADOW_NONE,
                             "label_widget", label,
                             "child", g_object_new(gtk_alignment_get_type(),
                                       "left_padding", 12,
                                       "top_padding", 6,
                                       "child", section, NULL),
                             NULL);
                gtk_widget_show_all (frame);
                gtk_box_pack_start ((GtkBox *) page, frame, FALSE, FALSE, 0);
                wn->frame = frame;
            }
        nopage:
            if (wn->widget && wn->widget != section) {
                d(printf("destroy old widget for section '%s'\n", item->path));
                gtk_widget_destroy (wn->widget);
            }

            d(printf("Item %s, setting section widget\n", wn->item->path));

            sectionno++;
            wn->widget = section;
            if (section)
                g_signal_connect (
                    section, "destroy",
                    G_CALLBACK (ec_widget_destroyed), wn);
            sectionnode = wn;
            break;
        case E_CONFIG_ITEM:
        case E_CONFIG_ITEM_TABLE:
            /* generated sections never retain their widgets on a rebuild */
            if (sectionnode->item->factory == NULL)
                wn->widget = NULL;

            /* ITEMs are called with the section parent.
             * The type depends on the section type,
             * either a GtkTable, or a GtkVBox */
            w = NULL;
            if (section == NULL) {
                wn->widget = NULL;
                wn->frame = NULL;
                g_warning("EConfig item has no parent section: %s", item->path);
            } else if ((item->type == E_CONFIG_ITEM && !GTK_IS_BOX (section))
                 || (item->type == E_CONFIG_ITEM_TABLE && !GTK_IS_TABLE (section)))
                g_warning("EConfig item parent type is incorrect: %s", item->path);
            else if (item->factory)
                w = item->factory (
                    emp, item, section, wn->widget,
                    0, wn->context->data);

            d(printf("item %d:%s widget %p\n", itemno, item->path, w));

            d(printf ("  item %s: (%s - %s)\n",
                  item->path,
                  g_type_name_from_instance ((GTypeInstance *) w),
                  gtk_widget_get_visible (w) ? "visible" : "invisible"));

            if (wn->widget && wn->widget != w) {
                d(printf("destroy old widget for item '%s'\n", item->path));
                gtk_widget_destroy (wn->widget);
            }

            wn->widget = w;
            if (w) {
                g_signal_connect (
                    w, "destroy",
                    G_CALLBACK (ec_widget_destroyed), wn);
                itemno++;

                if (gtk_widget_get_visible (w))
                    n_visible_widgets++;
            }
            break;
        }
    }

    /* If the last section doesn't contain any visible widgets, hide it */
    if (sectionnode != NULL && sectionnode->frame != NULL) {
        d(printf ("Section %s - %d visible widgets (frame=%p)\n", sectionnode->item->path, n_visible_widgets, sectionnode->frame));
        if ((sectionnode->empty = (itemno == 0 || n_visible_widgets == 0))) {
            if (sectionnode->real_frame)
                gtk_widget_hide (sectionnode->real_frame);

            if (sectionnode->frame)
                gtk_widget_hide (sectionnode->frame);

            sectionno--;
        } else {
            if (sectionnode->real_frame)
                gtk_widget_show (sectionnode->real_frame);

            if (sectionnode->frame)
                gtk_widget_show (sectionnode->frame);
        }
        d(printf("%s section '%s' [sections=%d]\n", sectionnode->empty?"hiding":"showing", sectionnode->item->path, sectionno));
    }

    /* If the last page doesn't contain anything, hide it */
    if (pagenode != NULL && pagenode->frame != NULL) {
        if ((pagenode->empty = sectionno == 0)) {
            gtk_widget_hide (pagenode->frame);
            pageno--;
        } else
            gtk_widget_show (pagenode->frame);
        d(printf("%s page '%s' [section=%d]\n", pagenode->empty?"hiding":"showing", pagenode->item->path, pageno));
    }

    if (book) {
        /* make this depend on flags?? */
        if (gtk_notebook_get_n_pages ((GtkNotebook *) book) == 1) {
            gtk_notebook_set_show_tabs ((GtkNotebook *) book, FALSE);
            gtk_notebook_set_show_border ((GtkNotebook *) book, FALSE);
        }
    }

    if (is_assistant && last_active_link != NULL) {
        GtkAssistant *assistant;
        struct _widget_node *wn;
        gint page_index = -1;

        wn = last_active_link->data;
        assistant = GTK_ASSISTANT (emp->widget);
        ec_assistant_find_page (emp, wn->frame, &page_index);
        gtk_assistant_set_current_page (assistant, page_index);
    }
}

/**
 * e_config_set_target:
 * @emp: An initialised EConfig.
 * @target: A target allocated from @emp.
 *
 * Sets the target object for the config window.  Generally the target
 * is set only once, and will supply its own "changed" signal which
 * can be used to drive the modal.  This is a virtual method so that
 * the implementing class can connect to the changed signal and
 * initiate a e_config_target_changed() call where appropriate.
 **/
void
e_config_set_target (EConfig *emp,
                     EConfigTarget *target)
{
    if (emp->target != target)
        ((EConfigClass *) G_OBJECT_GET_CLASS (emp))->set_target (emp, target);
}

static void
ec_widget_destroy (GtkWidget *w,
                   EConfig *ec)
{
    if (ec->target) {
        e_config_target_free (ec, ec->target);
        ec->target = NULL;
    }

    g_object_unref (ec);
}

/**
 * e_config_create_widget:
 * @emp: An initialised EConfig object.
 *
 * Create the widget described by @emp.  Only the core widget
 * appropriate for the given type is created, i.e. a GtkNotebook for
 * the E_CONFIG_BOOK type and a GtkAssistant for the E_CONFIG_ASSISTANT
 * type.
 *
 * This object will be self-driving, but will not close itself once
 * complete.
 *
 * Unless reffed otherwise, the management object @emp will be
 * finalized when the widget is.
 *
 * Return value: The widget, also available in @emp.widget
 **/
GtkWidget *
e_config_create_widget (EConfig *emp)
{
    EConfigPrivate *p = emp->priv;
    GPtrArray *items = g_ptr_array_new ();
    GList *link;
    GSList *l;
    gint i;

    g_return_val_if_fail (emp->target != NULL, NULL);

    ec_add_static_items (emp);

    /* FIXME: need to override old ones with new names */
    link = p->menus;
    while (link != NULL) {
        struct _menu_node *mnode = link->data;

        for (l = mnode->menu; l; l = l->next) {
            struct _EConfigItem *item = l->data;
            struct _widget_node *wn = g_malloc0 (sizeof (*wn));

            wn->item = item;
            wn->context = mnode;
            wn->config = emp;
            g_ptr_array_add (items, wn);
        }

        link = g_list_next (link);
    }

    qsort (items->pdata, items->len, sizeof (items->pdata[0]), ep_cmp);

    for (i = 0; i < items->len; i++)
        p->widgets = g_list_append (p->widgets, items->pdata[i]);

    g_ptr_array_free (items, TRUE);
    ec_rebuild (emp);

    /* auto-unref it */
    g_signal_connect (emp->widget, "destroy", G_CALLBACK(ec_widget_destroy), emp);

    /* FIXME: for some reason ec_rebuild puts the widget on page 1, this is just to override that */
    if (emp->type == E_CONFIG_BOOK)
        gtk_notebook_set_current_page ((GtkNotebook *) emp->widget, 0);
    else {
        gtk_window_set_position (GTK_WINDOW (emp->widget), GTK_WIN_POS_CENTER);
    }

    return emp->widget;
}

static void
ec_dialog_response (GtkWidget *d,
                    gint id,
                    EConfig *ec)
{
    if (id == GTK_RESPONSE_OK)
        e_config_commit (ec);
    else
        e_config_abort (ec);

    gtk_widget_destroy (d);
}

/**
 * e_config_create_window:
 * @emp: Initialised and configured EMConfig derived instance.
 * @parent: Parent window or NULL.
 * @title: Title of window or dialog.
 *
 * Create a managed GtkWindow object from @emp.  This window will be
 * fully driven by the EConfig @emp.  If @emp.type is
 * @E_CONFIG_ASSISTANT, then this will be a toplevel GtkWindow containing
 * a GtkAssistant.  If it is @E_CONFIG_BOOK then it will be a GtkDialog
 * containing a Notebook.
 *
 * Unless reffed otherwise, the management object @emp will be
 * finalized when the widget is.
 *
 * Return value: The window widget.  This is also stored in @emp.window.
 **/
GtkWidget *
e_config_create_window (EConfig *emp,
                        GtkWindow *parent,
                        const gchar *title)
{
    GtkWidget *window;

    e_config_create_widget (emp);

    if (emp->type == E_CONFIG_BOOK) {
        GtkWidget *content_area;

        window = gtk_dialog_new_with_buttons (
            title, parent,
            GTK_DIALOG_DESTROY_WITH_PARENT,
            GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
            GTK_STOCK_APPLY, GTK_RESPONSE_OK,
            NULL);
        g_signal_connect (
            window, "response",
            G_CALLBACK (ec_dialog_response), emp);

        gtk_container_set_border_width (GTK_CONTAINER (window), 5);
        gtk_container_set_border_width (GTK_CONTAINER (emp->widget), 5);

        content_area =
            gtk_dialog_get_content_area (GTK_DIALOG (window));
        gtk_box_pack_start (
            GTK_BOX (content_area), emp->widget, TRUE, TRUE, 0);
    } else {
        /* response is handled directly by the assistant stuff */
        window = emp->widget;
        gtk_window_set_title (GTK_WINDOW (window), title);
    }

    emp->window = window;
    gtk_widget_show (window);

    return window;
}

static void
ec_call_page_check (EConfig *emp)
{
    if (emp->type == E_CONFIG_ASSISTANT) {
        ec_assistant_check_current (emp);
    } else {
        if (emp->window) {
            if (e_config_page_check (emp, NULL)) {
                gtk_dialog_set_response_sensitive ((GtkDialog *) emp->window, GTK_RESPONSE_OK, TRUE);
            } else {
                gtk_dialog_set_response_sensitive ((GtkDialog *) emp->window, GTK_RESPONSE_OK, FALSE);
            }
        }
    }
}

static gboolean
ec_idle_handler_for_rebuild (gpointer data)
{
    EConfig *emp = (EConfig *) data;

    ec_rebuild (emp);
    ec_call_page_check (emp);

    return FALSE;
}

/**
 * e_config_target_changed:
 * @emp: an #EConfig
 * @how: an enum value indicating how the target has changed
 *
 * Indicate that the target has changed.  This may be called by the
 * self-aware target itself, or by the driving code.  If @how is
 * %E_CONFIG_TARGET_CHANGED_REBUILD, then the entire configuration
 * widget may be recreated based on the changed target.
 *
 * This is used to sensitise Assistant next/back buttons and the Apply
 * button for the Notebook mode.
 **/
void
e_config_target_changed (EConfig *emp,
                         e_config_target_change_t how)
{
    if (how == E_CONFIG_TARGET_CHANGED_REBUILD) {
        g_idle_add (ec_idle_handler_for_rebuild, emp);
    } else {
        ec_call_page_check (emp);
    }

    /* virtual method/signal? */
}

/**
 * e_config_abort:
 * @config: an #EConfig
 *
 * Signify that the stateful configuration changes must be discarded
 * to all listeners.  This is used by self-driven assistant or notebook, or
 * may be used by code using the widget directly.
 **/
void
e_config_abort (EConfig *config)
{
    g_return_if_fail (E_IS_CONFIG (config));

    g_signal_emit (config, signals[ABORT], 0);
}

/**
 * e_config_commit:
 * @ec: an #EConfig
 *
 * Signify that the stateful configuration changes should be saved.
 * This is used by the self-driven assistant or notebook, or may be used
 * by code driving the widget directly.
 **/
void
e_config_commit (EConfig *config)
{
    g_return_if_fail (E_IS_CONFIG (config));

    g_signal_emit (config, signals[COMMIT], 0);
}

/**
 * e_config_page_check:
 * @config: an #EConfig
 * @pageid: the path of the page item
 *
 * Check that a given page is complete.  If @pageid is NULL, then check
 * the whole config.  No check is made that the page actually exists.
 *
 * Return value: FALSE if the data is inconsistent/incomplete.
 **/
gboolean
e_config_page_check (EConfig *config,
                     const gchar *pageid)
{
    GList *link;

    link = config->priv->checks;

    while (link != NULL) {
        struct _check_node *node = link->data;

        if ((pageid == NULL
             || node->pageid == NULL
             || strcmp (node->pageid, pageid) == 0)
            && !node->check (config, pageid, node->data)) {
            return FALSE;
        }

        link = g_list_next (link);
    }

    return TRUE;
}

/**
 * e_config_page_get:
 * @ec:
 * @pageid: The path of the page item.
 *
 * Retrieve the page widget corresponding to @pageid.
 *
 * Return value: The page widget.  It will be the root GtkNotebook
 * container or the GtkVBox object inside the assistant.
 **/
GtkWidget *
e_config_page_get (EConfig *ec,
                   const gchar *pageid)
{
    GList *link;

    link = ec->priv->widgets;

    while (link != NULL) {
        struct _widget_node *wn = link->data;

        if (!wn->empty
            && (wn->item->type == E_CONFIG_PAGE
            || wn->item->type == E_CONFIG_PAGE_START
            || wn->item->type == E_CONFIG_PAGE_FINISH
            || wn->item->type == E_CONFIG_PAGE_PROGRESS)
            && !strcmp (wn->item->path, pageid))
            return wn->frame;

        link = g_list_next (link);
    }

    return NULL;
}

/**
 * e_config_page_next:
 * @ec:
 * @pageid: The path of the page item.
 *
 * Find the path of the next visible page after @pageid.  If @pageid
 * is NULL then find the first visible page.
 *
 * Return value: The path of the next page, or @NULL if @pageid was the
 * last configured and visible page.
 **/
const gchar *
e_config_page_next (EConfig *ec,
                    const gchar *pageid)
{
    GList *link;
    gint found;

    link = g_list_first (ec->priv->widgets);
    found = pageid == NULL ? 1 : 0;

    while (link != NULL) {
        struct _widget_node *wn = link->data;

        if (!wn->empty
            && (wn->item->type == E_CONFIG_PAGE
            || wn->item->type == E_CONFIG_PAGE_START
            || wn->item->type == E_CONFIG_PAGE_FINISH
            || wn->item->type == E_CONFIG_PAGE_PROGRESS)) {
            if (found)
                return wn->item->path;
            else if (strcmp (wn->item->path, pageid) == 0)
                found = 1;
        }

        link = g_list_next (link);
    }

    return NULL;
}

/**
 * e_config_page_prev:
 * @ec: an #EConfig
 * @pageid: The path of the page item.
 *
 * Find the path of the previous visible page before @pageid.  If @pageid
 * is NULL then find the last visible page.
 *
 * Return value: The path of the previous page, or @NULL if @pageid was the
 * first configured and visible page.
 **/
const gchar *
e_config_page_prev (EConfig *ec,
                    const gchar *pageid)
{
    GList *link;
    gint found;

    link = g_list_last (ec->priv->widgets);
    found = pageid == NULL ? 1 : 0;

    while (link != NULL) {
        struct _widget_node *wn = link->data;

        if (!wn->empty
            && (wn->item->type == E_CONFIG_PAGE
            || wn->item->type == E_CONFIG_PAGE_START
            || wn->item->type == E_CONFIG_PAGE_FINISH
            || wn->item->type == E_CONFIG_PAGE_PROGRESS)) {
            if (found)
                return wn->item->path;
            else if (strcmp (wn->item->path, pageid) == 0)
                found = 1;
        }

        link = g_list_previous (link);
    }

    return NULL;
}

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

/**
 * e_config_class_add_factory:
 * @class: Implementing class pointer.
 * @id: The name of the configuration window you're interested in.
 * This may be NULL to be called for all windows.
 * @func: An EConfigFactoryFunc to call when the window @id is being
 * created.
 * @data: Callback data.
 *
 * Add a config factory which will be called to add_items() any
 * extra items's if wants to, to the current Config window.
 *
 * TODO: Make the id a pattern?
 *
 * Return value: A handle to the factory.
 **/
EConfigFactory *
e_config_class_add_factory (EConfigClass *class,
                            const gchar *id,
                            EConfigFactoryFunc func,
                            gpointer user_data)
{
    EConfigFactory *factory;

    g_return_val_if_fail (E_IS_CONFIG_CLASS (class), NULL);
    g_return_val_if_fail (func != NULL, NULL);

    factory = g_slice_new0 (EConfigFactory);
    factory->id = g_strdup (id);
    factory->func = func;
    factory->user_data = user_data;

    class->factories = g_list_append (class->factories, factory);

    return factory;
}

/**
 * e_config_class_remove_factory:
 * @factory: an #EConfigFactory
 *
 * Removes a config factory.
 **/
void
e_config_class_remove_factory (EConfigClass *class,
                               EConfigFactory *factory)
{
    g_return_if_fail (E_IS_CONFIG_CLASS (class));
    g_return_if_fail (factory != NULL);

    class->factories = g_list_remove (class->factories, factory);

    g_free (factory->id);

    g_slice_free (EConfigFactory, factory);
}

/**
 * e_config_target_new:
 * @ep: Parent EConfig object.
 * @type: type, up to implementor
 * @size: Size of object to allocate.
 *
 * Allocate a new config target suitable for this class.  Implementing
 * classes will define the actual content of the target.
 **/
gpointer e_config_target_new (EConfig *ep, gint type, gsize size)
{
    EConfigTarget *t;

    if (size < sizeof (EConfigTarget)) {
        g_warning ("Size is less than size of EConfigTarget\n");
        size = sizeof (EConfigTarget);
    }

    t = g_malloc0 (size);
    t->config = ep;
    g_object_ref (ep);
    t->type = type;

    return t;
}

/**
 * e_config_target_free:
 * @ep: Parent EConfig object.
 * @o: The target to fre.
 *
 * Free a target.  The implementing class can override this method to
 * free custom targets.
 **/
void
e_config_target_free (EConfig *ep,
                      gpointer o)
{
    EConfigTarget *t = o;

    ((EConfigClass *) G_OBJECT_GET_CLASS (ep))->target_free (ep, t);
}

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

/* Config menu plugin handler */

/*
 * <e-plugin
 *   class="org.gnome.mail.plugin.config:1.0"
 *   id="org.gnome.mail.plugin.config.item:1.0"
 *   type="shlib"
 *   location="/opt/gnome2/lib/camel/1.0/libcamelimap.so"
 *   name="imap"
 *   description="IMAP4 and IMAP4v1 mail store">
 *   <hook class="org.gnome.mail.configMenu:1.0"
 *         handler="HandleConfig">
 *   <menu id="any" target="select">
 *    <item
 *     type="item|toggle|radio|image|submenu|bar"
 *     active
 *     path="foo/bar"
 *     label="label"
 *     icon="foo"
 *     activate="ep_view_emacs"/>
 *   </menu>
 * </e-plugin>
 */

#define emph ((EConfigHook *)eph)

static const EPluginHookTargetKey ech_item_types[] = {
    { "book", E_CONFIG_BOOK },
    { "assistant", E_CONFIG_ASSISTANT },

    { "page", E_CONFIG_PAGE },
    { "page_start", E_CONFIG_PAGE_START },
    { "page_finish", E_CONFIG_PAGE_FINISH },
    { "section", E_CONFIG_SECTION },
    { "section_table", E_CONFIG_SECTION_TABLE },
    { "item", E_CONFIG_ITEM },
    { "item_table", E_CONFIG_ITEM_TABLE },
    { NULL },
};

G_DEFINE_TYPE (
    EConfigHook,
    e_config_hook,
    E_TYPE_PLUGIN_HOOK)

static void
ech_commit (EConfig *ec,
            EConfigHookGroup *group)
{
    if (group->commit && group->hook->hook.plugin->enabled)
        e_plugin_invoke (group->hook->hook.plugin, group->commit, ec->target);
}

static void
ech_abort (EConfig *ec,
           EConfigHookGroup *group)
{
    if (group->abort && group->hook->hook.plugin->enabled)
        e_plugin_invoke (group->hook->hook.plugin, group->abort, ec->target);
}

static gboolean
ech_check (EConfig *ec,
           const gchar *pageid,
           gpointer data)
{
    EConfigHookGroup *group = data;
    EConfigHookPageCheckData hdata;

    if (!group->hook->hook.plugin->enabled)
        return TRUE;

    hdata.config = ec;
    hdata.target = ec->target;
    hdata.pageid = pageid?pageid:"";

    return GPOINTER_TO_INT (e_plugin_invoke (group->hook->hook.plugin, group->check, &hdata));
}

static void
ech_config_factory (EConfig *emp,
                    gpointer data)
{
    EConfigHookGroup *group = data;

    d(printf("config factory called %s\n", group->id?group->id:"all menus"));

    if (emp->target->type != group->target_type
        || !group->hook->hook.plugin->enabled)
        return;

    if (group->items) {
        e_config_add_items (emp, group->items, NULL, group);
        g_signal_connect (
            emp, "abort",
            G_CALLBACK (ech_abort), group);
        g_signal_connect (
            emp, "commit",
            G_CALLBACK (ech_commit), group);
    }

    if (group->check)
        e_config_add_page_check (emp, NULL, ech_check, group);
}

static void
emph_free_item (struct _EConfigItem *item)
{
    g_free (item->path);
    g_free (item->label);
    g_free (item->user_data);
    g_free (item);
}

static void
emph_free_group (EConfigHookGroup *group)
{
    g_slist_foreach (group->items, (GFunc) emph_free_item, NULL);
    g_slist_free (group->items);

    g_free (group->id);
    g_free (group);
}

static GtkWidget *
ech_config_widget_factory (EConfig *config,
                           EConfigItem *item,
                           GtkWidget *parent,
                           GtkWidget *old,
                           gint position,
                           gpointer data)
{
    EConfigHookGroup *group = data;
    EConfigHookItemFactoryData factory_data;
    EPlugin *plugin;

    factory_data.config = config;
    factory_data.item = item;
    factory_data.target = config->target;
    factory_data.parent = parent;
    factory_data.old = old;
    factory_data.position = position;

    plugin = group->hook->hook.plugin;
    return e_plugin_invoke (plugin, item->user_data, &factory_data);
}

static GtkWidget *
ech_config_section_factory (EConfig *config,
                            EConfigItem *item,
                            GtkWidget *parent,
                            GtkWidget *old,
                            gint position,
                            gpointer data,
                            GtkWidget **real_frame)
{
    EConfigHookGroup *group = data;
    GtkWidget *label = NULL;
    GtkWidget *widget;
    EPlugin *plugin;

    if (item->label != NULL) {
        const gchar *translated;
        gchar *markup;

        translated = gettext (item->label);
        markup = g_markup_printf_escaped ("<b>%s</b>", translated);

        label = gtk_label_new (markup);
        gtk_label_set_use_markup (GTK_LABEL (label), TRUE);
        gtk_misc_set_alignment (GTK_MISC (label), 0.0, 0.5);
        gtk_widget_show (label);

        g_free (markup);
    }

    widget = gtk_frame_new (NULL);
    gtk_frame_set_label_widget (GTK_FRAME (widget), label);
    gtk_frame_set_shadow_type (GTK_FRAME (widget), GTK_SHADOW_NONE);
    gtk_box_pack_start (GTK_BOX (parent), widget, FALSE, FALSE, 0);

    *real_frame = widget;

    /* This is why we have a custom factory for sections.
     * When the plugin is disabled the frame is invisible. */
    plugin = group->hook->hook.plugin;
    g_object_bind_property (
        plugin, "enabled",
        widget, "visible",
        G_BINDING_SYNC_CREATE);

    parent = widget;

    widget = gtk_alignment_new (0.0, 0.0, 1.0, 1.0);
    gtk_alignment_set_padding (GTK_ALIGNMENT (widget), 6, 0, 12, 0);
    gtk_container_add (GTK_CONTAINER (parent), widget);
    gtk_widget_show (widget);

    parent = widget;

    switch (item->type) {
        case E_CONFIG_SECTION:
            widget = gtk_vbox_new (FALSE, 6);
            break;

        case E_CONFIG_SECTION_TABLE:
            widget = gtk_table_new (1, 1, FALSE);
            gtk_table_set_col_spacings (GTK_TABLE (widget), 6);
            gtk_table_set_row_spacings (GTK_TABLE (widget), 6);
            break;

        default:
            g_return_val_if_reached (NULL);
    }

    gtk_container_add (GTK_CONTAINER (parent), widget);
    gtk_widget_show (widget);

    return widget;
}

static struct _EConfigItem *
emph_construct_item (EPluginHook *eph,
                     EConfigHookGroup *menu,
                     xmlNodePtr root,
                     EConfigHookTargetMap *map)
{
    struct _EConfigItem *item;

    d(printf("  loading config item\n"));
    item = g_malloc0 (sizeof (*item));
    if ((item->type = e_plugin_hook_id(root, ech_item_types, "type")) == -1)
        goto error;
    item->path = e_plugin_xml_prop(root, "path");
    item->label = e_plugin_xml_prop_domain(root, "label", eph->plugin->domain);
    item->user_data = e_plugin_xml_prop(root, "factory");

    if (item->path == NULL
        || (item->label == NULL && item->user_data == NULL))
        goto error;

    if (item->user_data)
        item->factory = ech_config_widget_factory;
    else if (item->type == E_CONFIG_SECTION)
        item->factory = (EConfigItemFactoryFunc) ech_config_section_factory;
    else if (item->type == E_CONFIG_SECTION_TABLE)
        item->factory = (EConfigItemFactoryFunc) ech_config_section_factory;

    d(printf("   path=%s label=%s factory=%s\n", item->path, item->label, (gchar *)item->user_data));

    return item;
error:
    d(printf("error!\n"));
    emph_free_item (item);
    return NULL;
}

static EConfigHookGroup *
emph_construct_menu (EPluginHook *eph,
                     xmlNodePtr root)
{
    EConfigHookGroup *menu;
    xmlNodePtr node;
    EConfigHookTargetMap *map;
    EConfigHookClass *class = (EConfigHookClass *) G_OBJECT_GET_CLASS (eph);
    gchar *tmp;

    d(printf(" loading menu\n"));
    menu = g_malloc0 (sizeof (*menu));

    tmp = (gchar *)xmlGetProp(root, (const guchar *)"target");
    if (tmp == NULL)
        goto error;
    map = g_hash_table_lookup (class->target_map, tmp);
    xmlFree (tmp);
    if (map == NULL)
        goto error;

    menu->target_type = map->id;
    menu->id = e_plugin_xml_prop(root, "id");
    if (menu->id == NULL) {
        g_warning("Plugin '%s' missing 'id' field in group for '%s'\n", eph->plugin->name,
              ((EPluginHookClass *) G_OBJECT_GET_CLASS (eph))->id);
        goto error;
    }
    menu->check = e_plugin_xml_prop(root, "check");
    menu->commit = e_plugin_xml_prop(root, "commit");
    menu->abort = e_plugin_xml_prop(root, "abort");
    menu->hook = (EConfigHook *) eph;
    node = root->children;
    while (node) {
        if (0 == strcmp((gchar *)node->name, "item")) {
            struct _EConfigItem *item;

            item = emph_construct_item (eph, menu, node, map);
            if (item)
                menu->items = g_slist_append (menu->items, item);
        }
        node = node->next;
    }

    return menu;
error:
    emph_free_group (menu);
    return NULL;
}

static gint
emph_construct (EPluginHook *eph,
                EPlugin *ep,
                xmlNodePtr root)
{
    xmlNodePtr node;
    EConfigClass *class;

    d(printf("loading config hook\n"));

    if (((EPluginHookClass *) e_config_hook_parent_class)->construct (eph, ep, root) == -1)
        return -1;

    class = ((EConfigHookClass *) G_OBJECT_GET_CLASS (eph))->config_class;

    node = root->children;
    while (node) {
        if (strcmp((gchar *)node->name, "group") == 0) {
            EConfigHookGroup *group;

            group = emph_construct_menu (eph, node);
            if (group) {
                e_config_class_add_factory (class, group->id, ech_config_factory, group);
                emph->groups = g_slist_append (emph->groups, group);
            }
        }
        node = node->next;
    }

    eph->plugin = ep;

    return 0;
}

static void
emph_finalize (GObject *o)
{
    EPluginHook *eph = (EPluginHook *) o;

    g_slist_foreach (emph->groups, (GFunc) emph_free_group, NULL);
    g_slist_free (emph->groups);

    ((GObjectClass *) e_config_hook_parent_class)->finalize (o);
}

static void
e_config_hook_class_init (EConfigHookClass *class)
{
    GObjectClass *object_class;
    EPluginHookClass *plugin_hook_class;

    object_class = G_OBJECT_CLASS (class);
    object_class->finalize = emph_finalize;

    plugin_hook_class = E_PLUGIN_HOOK_CLASS (class);
    plugin_hook_class->construct = emph_construct;

    /* this is actually an abstract implementation but list it anyway */
    plugin_hook_class->id = "org.gnome.evolution.config:1.0";

    class->target_map = g_hash_table_new (g_str_hash, g_str_equal);
    class->config_class = g_type_class_ref (e_config_get_type ());
}

static void
e_config_hook_init (EConfigHook *hook)
{
}

/**
 * e_config_hook_class_add_target_map:
 *
 * @class: The dervied EconfigHook class.
 * @map: A map used to describe a single EConfigTarget type for this
 * class.
 *
 * Add a targe tmap to a concrete derived class of EConfig.  The
 * target map enumates the target types available for the implenting
 * class.
 **/
void
e_config_hook_class_add_target_map (EConfigHookClass *class,
                                    const EConfigHookTargetMap *map)
{
    g_hash_table_insert (class->target_map, (gpointer) map->type, (gpointer) map);
}