path: root/calendar/gui/e-tasks.c

/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
/* e-tasks.c
 *
 * Copyright (C) 2001  Ximian, Inc.
 * Copyright (C) 2001  Ximian, Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * Authors: Federico Mena Quintero <federico@ximian.com>
 *      Damon Chaplin <damon@ximian.com>
 */

#include <config.h>
#include <gnome.h>
#include <gal/util/e-util.h>
#include <gal/e-table/e-table-scrolled.h>
#include <gal/menus/gal-view-instance.h>
#include <gal/menus/gal-view-factory-etable.h>
#include <gal/menus/gal-view-etable.h>

#include "e-util/e-url.h"
#include "widgets/menus/gal-view-menus.h"
#include "dialogs/delete-error.h"
#include "dialogs/task-editor.h"
#include "cal-search-bar.h"
#include "calendar-config.h"
#include "calendar-component.h"
#include "comp-util.h"
#include "misc.h"

#include "e-tasks.h"

/* A list of all of the ETasks widgets in use. We use this to update the
   user preference settings. This will change when we switch to GConf. */
static GList *all_tasks = NULL;


/* Private part of the GnomeCalendar structure */
struct _ETasksPrivate {
    /* The calendar client object we monitor */
    CalClient   *client;
    CalQuery    *query;
    
    /* The ECalendarTable showing the tasks. */
    GtkWidget   *tasks_view;

    /* Calendar search bar for tasks */
    GtkWidget *search_bar;

    /* View instance and the view menus handler */
    GalViewInstance *view_instance;
    GalViewMenus *view_menus;
};


static void e_tasks_class_init (ETasksClass *class);
static void e_tasks_init (ETasks *tasks);
static void setup_widgets (ETasks *tasks);
static void e_tasks_destroy (GtkObject *object);

static void cal_opened_cb (CalClient *client, CalClientOpenStatus status, gpointer data);
static void backend_error_cb (CalClient *client, const char *message, gpointer data);

/* Signal IDs */
enum {
    SELECTION_CHANGED,
    LAST_SIGNAL
};

static GtkTableClass *parent_class;
static guint e_tasks_signals[LAST_SIGNAL] = { 0 };


E_MAKE_TYPE (e_tasks, "ETasks", ETasks,
         e_tasks_class_init, e_tasks_init,
         GTK_TYPE_TABLE)


/* Class initialization function for the gnome calendar */
    static void
e_tasks_class_init (ETasksClass *class)
{
    GtkObjectClass *object_class;

    object_class = (GtkObjectClass *) class;

    parent_class = gtk_type_class (GTK_TYPE_TABLE);

    e_tasks_signals[SELECTION_CHANGED] =
        gtk_signal_new ("selection_changed",
                GTK_RUN_LAST,
                G_TYPE_FROM_CLASS (object_class), 
                GTK_SIGNAL_OFFSET (ETasksClass, selection_changed),
                gtk_marshal_NONE__INT,
                GTK_TYPE_NONE, 1,
                GTK_TYPE_INT);

    object_class->destroy = e_tasks_destroy;

    class->selection_changed = NULL;
}


/* Object initialization function for the gnome calendar */
static void
e_tasks_init (ETasks *tasks)
{
    ETasksPrivate *priv;

    priv = g_new0 (ETasksPrivate, 1);
    tasks->priv = priv;

    priv->client = NULL;
    priv->query = NULL;
    priv->view_instance = NULL;
    priv->view_menus = NULL;
}

/* Callback used when the selection changes in the table. */
static void
table_selection_change_cb (ETable *etable, gpointer data)
{
    ETasks *tasks;
    int n_selected;

    tasks = E_TASKS (data);

    n_selected = e_table_selected_count (etable);
    gtk_signal_emit (GTK_OBJECT (tasks), e_tasks_signals[SELECTION_CHANGED],
             n_selected);
}

/* Callback used when the sexp in the search bar changes */
static void
search_bar_sexp_changed_cb (CalSearchBar *cal_search, const char *sexp, gpointer data)
{
    ETasks *tasks;
    ETasksPrivate *priv;
    CalendarModel *model;

    tasks = E_TASKS (data);
    priv = tasks->priv;

    model = e_calendar_table_get_model (E_CALENDAR_TABLE (priv->tasks_view));
    calendar_model_set_query (model, sexp);
}

/* Callback used when the selected category in the search bar changes */
static void
search_bar_category_changed_cb (CalSearchBar *cal_search, const char *category, gpointer data)
{
    ETasks *tasks;
    ETasksPrivate *priv;
    CalendarModel *model;

    tasks = E_TASKS (data);
    priv = tasks->priv;

    model = e_calendar_table_get_model (E_CALENDAR_TABLE (priv->tasks_view));
    calendar_model_set_default_category (model, category);
}

#define E_TASKS_TABLE_DEFAULT_STATE                 \
    "<?xml version=\"1.0\"?>"                   \
    "<ETableState>"                         \
    "<column source=\"13\"/>"                   \
    "<column source=\"14\"/>"                   \
    "<column source=\"9\"/>"                    \
    "<column source=\"5\"/>"                    \
    "<grouping/>"                           \
    "</ETableState>"


static void
setup_widgets (ETasks *tasks)
{
    ETasksPrivate *priv;
    ETable *etable;
    CalendarModel *model;

    priv = tasks->priv;

    priv->search_bar = cal_search_bar_new ();
    g_signal_connect (priv->search_bar, "sexp_changed",
              G_CALLBACK (search_bar_sexp_changed_cb), tasks);
    g_signal_connect (priv->search_bar, "category_changed",
              G_CALLBACK (search_bar_category_changed_cb), tasks);

    gtk_table_attach (GTK_TABLE (tasks), priv->search_bar, 0, 1, 0, 1,
              GTK_EXPAND | GTK_FILL | GTK_SHRINK, 0, 0, 0);
    gtk_widget_show (priv->search_bar);

    priv->tasks_view = e_calendar_table_new ();
    model = e_calendar_table_get_model (E_CALENDAR_TABLE (priv->tasks_view));
    calendar_model_set_new_comp_vtype (model, CAL_COMPONENT_TODO);

    etable = e_table_scrolled_get_table (
        E_TABLE_SCROLLED (E_CALENDAR_TABLE (priv->tasks_view)->etable));
    e_table_set_state (etable, E_TASKS_TABLE_DEFAULT_STATE);
    gtk_table_attach (GTK_TABLE (tasks), priv->tasks_view, 0, 1, 1, 2,
              GTK_EXPAND | GTK_FILL, GTK_EXPAND | GTK_FILL, 0, 0);
    gtk_widget_show (priv->tasks_view);

    calendar_config_configure_e_calendar_table (E_CALENDAR_TABLE (priv->tasks_view));

    g_signal_connect (etable, "selection_change", G_CALLBACK (table_selection_change_cb), tasks);
}

/* Callback used when the set of categories changes in the calendar client */
static void
client_categories_changed_cb (CalClient *client, GPtrArray *categories, gpointer data)
{
    ETasks *tasks;
    ETasksPrivate *priv;

    tasks = E_TASKS (data);
    priv = tasks->priv;

    cal_search_bar_set_categories (CAL_SEARCH_BAR (priv->search_bar), categories);
}

GtkWidget *
e_tasks_construct (ETasks *tasks)
{
    ETasksPrivate *priv;
    CalendarModel *model;

    g_return_val_if_fail (tasks != NULL, NULL);
    g_return_val_if_fail (E_IS_TASKS (tasks), NULL);

    priv = tasks->priv;

    setup_widgets (tasks);

    priv->client = cal_client_new ();
    if (!priv->client)
        return NULL;

    g_signal_connect (priv->client, "cal_opened",
              G_CALLBACK (cal_opened_cb), tasks);
    g_signal_connect (priv->client, "backend_error",
              G_CALLBACK (backend_error_cb), tasks);
    g_signal_connect (priv->client, "categories_changed",
              G_CALLBACK (client_categories_changed_cb), tasks);

    model = e_calendar_table_get_model (E_CALENDAR_TABLE (priv->tasks_view));
    g_assert (model != NULL);

    calendar_model_set_cal_client (model, priv->client, CALOBJ_TYPE_TODO);

    return GTK_WIDGET (tasks);
}


GtkWidget *
e_tasks_new (void)
{
    ETasks *tasks;

    tasks = g_object_new (e_tasks_get_type (), NULL);

    if (!e_tasks_construct (tasks)) {
        g_message ("e_tasks_new(): Could not construct the tasks GUI");
        g_object_unref (tasks);
        return NULL;
    }

    all_tasks = g_list_prepend (all_tasks, tasks);

    return GTK_WIDGET (tasks);
}


void
e_tasks_set_ui_component (ETasks *tasks,
              BonoboUIComponent *ui_component)
{
    g_return_if_fail (E_IS_TASKS (tasks));
    g_return_if_fail (ui_component == NULL || BONOBO_IS_UI_COMPONENT (ui_component));

    e_search_bar_set_ui_component (E_SEARCH_BAR (tasks->priv->search_bar), ui_component);
}


static void
e_tasks_destroy (GtkObject *object)
{
    ETasks *tasks;
    ETasksPrivate *priv;

    g_return_if_fail (object != NULL);
    g_return_if_fail (E_IS_TASKS (object));

    tasks = E_TASKS (object);
    priv = tasks->priv;

    if (priv) {
        if (priv->client) {
            g_object_unref (priv->client);
            priv->client = NULL;
        }
        
        g_free (priv);
        tasks->priv = NULL;
    
        all_tasks = g_list_remove (all_tasks, tasks);
    }

    if (GTK_OBJECT_CLASS (parent_class)->destroy)
        (* GTK_OBJECT_CLASS (parent_class)->destroy) (object);
}

static void
set_status_message (ETasks *tasks, const char *message)
{
    ETasksPrivate *priv;
    CalendarModel *model;
    
    priv = tasks->priv;
    
    model = e_calendar_table_get_model (E_CALENDAR_TABLE (priv->tasks_view));
    calendar_model_set_status_message (model, message);
}

gboolean
e_tasks_open            (ETasks     *tasks,
                 char       *file)
{
    ETasksPrivate *priv;
    char *message;
    EUri *uri;
    char *real_uri;
    char *urinopwd;

    g_return_val_if_fail (tasks != NULL, FALSE);
    g_return_val_if_fail (E_IS_TASKS (tasks), FALSE);
    g_return_val_if_fail (file != NULL, FALSE);

    priv = tasks->priv;

    uri = e_uri_new (file);
    if (!uri || !g_strncasecmp (uri->protocol, "file", 4))
        real_uri = g_concat_dir_and_file (file, "tasks.ics");
    else
        real_uri = g_strdup (file);

    urinopwd = get_uri_without_password (real_uri);
    message = g_strdup_printf (_("Opening tasks at %s"), urinopwd);
    set_status_message (tasks, message);
    g_free (message);
    g_free (urinopwd);

    if (!cal_client_open_calendar (priv->client, real_uri, FALSE)) {
        g_message ("e_tasks_open(): Could not issue the request");
        g_free (real_uri);
        e_uri_free (uri);

        return FALSE;
    }

    g_free (real_uri);
    e_uri_free (uri);

    return TRUE;
}


/* Displays an error to indicate that loading a calendar failed */
static void
load_error              (ETasks     *tasks,
                     const char *uri)
{
    char *msg;
    char *urinopwd;

    urinopwd = get_uri_without_password (uri);
    msg = g_strdup_printf (_("Could not load the tasks in `%s'"), urinopwd);
    gnome_error_dialog_parented (msg, GTK_WINDOW (gtk_widget_get_toplevel (GTK_WIDGET (tasks))));
    g_free (msg);
    g_free (urinopwd);
}

/* Displays an error to indicate that the specified URI method is not supported */
static void
method_error                (ETasks     *tasks,
                     const char *uri)
{
    char *msg;
    char *urinopwd;

    urinopwd = get_uri_without_password (uri);
    msg = g_strdup_printf (_("The method required to load `%s' is not supported"), urinopwd);
    gnome_error_dialog_parented (msg, GTK_WINDOW (gtk_widget_get_toplevel (GTK_WIDGET (tasks))));
    g_free (msg);
    g_free (urinopwd);
}

/* Displays an error to indicate permission problems */
static void
permission_error (ETasks *tasks, const char *uri)
{
    char *msg;
    char *urinopwd;

    urinopwd = get_uri_without_password (uri);
    msg = g_strdup_printf (_("You don't have permission to open the folder in `%s'"), urinopwd);
    gnome_error_dialog_parented (msg, GTK_WINDOW (gtk_widget_get_toplevel (GTK_WIDGET (tasks))));
    g_free (msg);
    g_free (urinopwd);
}

/* Callback from the calendar client when a calendar is opened */
static void
cal_opened_cb               (CalClient  *client,
                     CalClientOpenStatus status,
                     gpointer    data)
{
    ETasks *tasks;
    ETasksPrivate *priv;
    char *location;
    icaltimezone *zone;

    tasks = E_TASKS (data);
    priv = tasks->priv;

    set_status_message (tasks, NULL);

    switch (status) {
    case CAL_CLIENT_OPEN_SUCCESS:
        /* Everything is OK */

        /* Set the client's default timezone, if we have one. */
        location = calendar_config_get_timezone ();
        zone = icaltimezone_get_builtin_timezone (location);
        if (zone)
            cal_client_set_default_timezone (client, zone);
        return;

    case CAL_CLIENT_OPEN_ERROR:
        load_error (tasks, cal_client_get_uri (client));
        break;

    case CAL_CLIENT_OPEN_NOT_FOUND:
        /* bullshit; we did not specify only_if_exists */
        g_assert_not_reached ();
        return;

    case CAL_CLIENT_OPEN_METHOD_NOT_SUPPORTED:
        method_error (tasks, cal_client_get_uri (client));
        break;

    case CAL_CLIENT_OPEN_PERMISSION_DENIED:
        permission_error (tasks, cal_client_get_uri (client));
        break;

    default:
        g_assert_not_reached ();
    }
}

/* Callback from the calendar client when an error occurs in the backend */
static void
backend_error_cb (CalClient *client, const char *message, gpointer data)
{
    ETasks *tasks;
    ETasksPrivate *priv;
    char *errmsg;
    char *urinopwd;

    tasks = E_TASKS (data);
    priv = tasks->priv;

    urinopwd = get_uri_without_password (cal_client_get_uri (client));
    errmsg = g_strdup_printf (_("Error on %s:\n %s"), urinopwd, message);
    gnome_error_dialog_parented (errmsg, GTK_WINDOW (gtk_widget_get_toplevel (GTK_WIDGET (tasks))));
    g_free (errmsg);
    g_free (urinopwd);
}

/**
 * e_tasks_get_cal_client:
 * @tasks: An #ETasks.
 *
 * Queries the calendar client interface object that a tasks view is using.
 *
 * Return value: A calendar client interface object.
 **/
CalClient *
e_tasks_get_cal_client          (ETasks     *tasks)
{
    ETasksPrivate *priv;

    g_return_val_if_fail (E_IS_TASKS (tasks), NULL);

    priv = tasks->priv;

    return priv->client;
}


void
e_tasks_new_task            (ETasks     *tasks)
{
    ETasksPrivate *priv;
    TaskEditor *tedit;
    CalComponent *comp;
    const char *category;

    g_return_if_fail (E_IS_TASKS (tasks));

    priv = tasks->priv;

    tedit = task_editor_new (priv->client);

    comp = cal_comp_task_new_with_defaults (priv->client);

    category = cal_search_bar_get_category (CAL_SEARCH_BAR (priv->search_bar));
    cal_component_set_categories (comp, category);

    comp_editor_edit_comp (COMP_EDITOR (tedit), comp);
    g_object_unref (comp);

    comp_editor_focus (COMP_EDITOR (tedit));
}

/**
 * e_tasks_complete_selected:
 * @tasks: A tasks control widget
 * 
 * Marks the selected tasks complete
 **/
void
e_tasks_complete_selected (ETasks *tasks)
{
    ETasksPrivate *priv;
    ECalendarTable *cal_table;

    g_return_if_fail (tasks != NULL);
    g_return_if_fail (E_IS_TASKS (tasks));

    priv = tasks->priv;

    cal_table = E_CALENDAR_TABLE (priv->tasks_view);

    set_status_message (tasks, _("Completing tasks..."));
    e_calendar_table_complete_selected (cal_table);
    set_status_message (tasks, NULL);
}

/**
 * e_tasks_delete_selected:
 * @tasks: A tasks control widget.
 * 
 * Deletes the selected tasks in the task list.
 **/
void
e_tasks_delete_selected (ETasks *tasks)
{
    ETasksPrivate *priv;
    ECalendarTable *cal_table;

    g_return_if_fail (tasks != NULL);
    g_return_if_fail (E_IS_TASKS (tasks));

    priv = tasks->priv;

    cal_table = E_CALENDAR_TABLE (priv->tasks_view);
    set_status_message (tasks, _("Deleting selected objects..."));
    e_calendar_table_delete_selected (cal_table);
    set_status_message (tasks, NULL);
}

static char *
create_sexp (void)
{
    char *sexp;

    sexp = g_strdup ("(and (= (get-vtype) \"VTODO\") (is-completed?))");
#if 0
    g_print ("Calendar model sexp:\n%s\n", sexp);
#endif

    return sexp;
}

/* Callback used when a component is updated in the live query */
static void
query_obj_updated_cb (CalQuery *query, const char *uid,
              gboolean query_in_progress, int n_scanned, int total,
              gpointer data)
{
    ETasks *tasks;
    ETasksPrivate *priv;
    
    tasks = E_TASKS (data);
    priv = tasks->priv;
    
    delete_error_dialog (cal_client_remove_object (priv->client, uid), CAL_COMPONENT_TODO);
}

/* Callback used when an evaluation error occurs when running a query */
static void
query_eval_error_cb (CalQuery *query, const char *error_str, gpointer data)
{
    ETasks *tasks;
    ETasksPrivate *priv;
    
    tasks = E_TASKS (data);
    priv = tasks->priv;
    
    g_warning ("eval error: %s\n", error_str);

    set_status_message (tasks, NULL);

    g_signal_handlers_disconnect_matched (priv->query, G_SIGNAL_MATCH_DATA,
                          0, 0, NULL, NULL, tasks);
    g_object_unref (priv->query);
    priv->query = NULL;
}

static void
query_query_done_cb (CalQuery *query, CalQueryDoneStatus status, const char *error_str, gpointer data)
{
    ETasks *tasks;
    ETasksPrivate *priv;
    
    tasks = E_TASKS (data);
    priv = tasks->priv;
    
    if (status != CAL_QUERY_DONE_SUCCESS)
        g_warning ("query done: %s\n", error_str);

    set_status_message (tasks, NULL);

    g_signal_handlers_disconnect_matched (priv->query, G_SIGNAL_MATCH_DATA,
                          0, 0, NULL, NULL, tasks);
    g_object_unref (priv->query);
    priv->query = NULL;
}
/**
 * e_tasks_expunge:
 * @tasks: A tasks control widget
 * 
 * Removes all tasks marked as completed
 **/
void
e_tasks_delete_completed (ETasks *tasks)
{
    ETasksPrivate *priv;
    char *sexp;
    
    g_return_if_fail (tasks != NULL);
    g_return_if_fail (E_IS_TASKS (tasks));

    priv = tasks->priv;

    /* If we have a query, we are already expunging */
    if (priv->query)
        return;

    sexp = create_sexp ();

    set_status_message (tasks, _("Expunging"));
    priv->query = cal_client_get_query (priv->client, sexp);
    g_free (sexp);

    if (!priv->query) {
        set_status_message (tasks, NULL);
        g_message ("update_query(): Could not create the query");
        return;
    }

    g_signal_connect (priv->query, "obj_updated", G_CALLBACK (query_obj_updated_cb), tasks);
    g_signal_connect (priv->query, "query_done", G_CALLBACK (query_query_done_cb), tasks);
    g_signal_connect (priv->query, "eval_error", G_CALLBACK (query_eval_error_cb), tasks);
}

/* Callback used from the view collection when we need to display a new view */
static void
display_view_cb (GalViewInstance *instance, GalView *view, gpointer data)
{
    ETasks *tasks;

    tasks = E_TASKS (data);

    if (GAL_IS_VIEW_ETABLE (view)) {
        gal_view_etable_attach_table (GAL_VIEW_ETABLE (view), e_table_scrolled_get_table (E_TABLE_SCROLLED (E_CALENDAR_TABLE (tasks->priv->tasks_view)->etable)));
    }
}

/**
 * e_tasks_setup_view_menus:
 * @tasks: A tasks widget.
 * @uic: UI controller to use for the menus.
 * 
 * Sets up the #GalView menus for a tasks control.  This function should be
 * called from the Bonobo control activation callback for this tasks control.
 * Also, the menus should be discarded using e_tasks_discard_view_menus().
 **/
void
e_tasks_setup_view_menus (ETasks *tasks, BonoboUIComponent *uic)
{
    ETasksPrivate *priv;
    GalViewFactory *factory;
    ETableSpecification *spec;
    char *dir;
    static GalViewCollection *collection = NULL;

    g_return_if_fail (tasks != NULL);
    g_return_if_fail (E_IS_TASKS (tasks));
    g_return_if_fail (uic != NULL);
    g_return_if_fail (BONOBO_IS_UI_COMPONENT (uic));

    priv = tasks->priv;

    g_return_if_fail (priv->view_instance == NULL);

    g_assert (priv->view_instance == NULL);
    g_assert (priv->view_menus == NULL);

    /* Create the view instance */

    if (collection == NULL) {
        collection = gal_view_collection_new ();

        gal_view_collection_set_title (collection, _("Tasks"));

        dir = gnome_util_prepend_user_home ("/evolution/views/tasks/");
        gal_view_collection_set_storage_directories (collection,
                                 EVOLUTION_GALVIEWSDIR "/tasks/",
                                 dir);
        g_free (dir);

        /* Create the views */

        spec = e_table_specification_new ();
        e_table_specification_load_from_file (spec, 
                              EVOLUTION_ETSPECDIR "/e-calendar-table.etspec");

        factory = gal_view_factory_etable_new (spec);
        g_object_unref (spec);
        gal_view_collection_add_factory (collection, factory);
        g_object_unref (factory);

        /* Load the collection and create the menus */

        gal_view_collection_load (collection);
    }

    priv->view_instance = gal_view_instance_new (collection, cal_client_get_uri (priv->client));

    priv->view_menus = gal_view_menus_new (priv->view_instance);
    gal_view_menus_apply (priv->view_menus, uic, NULL);
    g_signal_connect (priv->view_instance, "display_view", G_CALLBACK (display_view_cb), tasks);
    display_view_cb (priv->view_instance, gal_view_instance_get_current_view (priv->view_instance), tasks);
}

/**
 * e_tasks_discard_view_menus:
 * @tasks: A tasks widget.
 * 
 * Discards the #GalView menus used by a tasks control.  This function should be
 * called from the Bonobo control deactivation callback for this tasks control.
 * The menus should have been set up with e_tasks_setup_view_menus().
 **/
void
e_tasks_discard_view_menus (ETasks *tasks)
{
    ETasksPrivate *priv;

    g_return_if_fail (tasks != NULL);
    g_return_if_fail (E_IS_TASKS (tasks));

    priv = tasks->priv;

    g_return_if_fail (priv->view_instance != NULL);

    g_assert (priv->view_instance != NULL);
    g_assert (priv->view_menus != NULL);

    g_object_unref (priv->view_instance);
    priv->view_instance = NULL;

    g_object_unref (priv->view_menus);
    priv->view_menus = NULL;
}

/**
 * e_tasks_get_calendar_table:
 * @tasks: A tasks widget.
 * 
 * Queries the #ECalendarTable contained in a tasks widget.
 * 
 * Return value: The #ECalendarTable that the tasks widget uses to display its
 * information.
 **/
ECalendarTable *
e_tasks_get_calendar_table (ETasks *tasks)
{
    ETasksPrivate *priv;

    g_return_val_if_fail (tasks != NULL, NULL);
    g_return_val_if_fail (E_IS_TASKS (tasks), NULL);

    priv = tasks->priv;
    return E_CALENDAR_TABLE (priv->tasks_view);
}

/* This updates all the preference settings for all the ETasks widgets in use.
 */
void
e_tasks_update_all_config_settings  (void)
{
    ETasks *tasks;
    ETasksPrivate *priv;
    GList *elem;
    char *location;
    icaltimezone *zone;

    location = calendar_config_get_timezone ();
    zone = icaltimezone_get_builtin_timezone (location);

    for (elem = all_tasks; elem; elem = elem->next) {
        tasks = E_TASKS (elem->data);
        priv = tasks->priv;

        calendar_config_configure_e_calendar_table (E_CALENDAR_TABLE (priv->tasks_view));

        if (zone)
            cal_client_set_default_timezone (priv->client, zone);
    }
}