path: root/calendar/cal-client/cal-client.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* Evolution calendar client
 *
 * Copyright (C) 2000 Helix Code, Inc.
 *
 * Author: Federico Mena-Quintero <federico@helixcode.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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.
 */

#include <config.h>
#include <gtk/gtksignal.h>
#include <liboaf/liboaf.h>

#include "cal-client-types.h"
#include "cal-client.h"
#include "cal-listener.h"



/* Loading state for the calendar client */
typedef enum {
    LOAD_STATE_NOT_LOADED,
    LOAD_STATE_LOADING,
    LOAD_STATE_LOADED
} LoadState;

/* Private part of the CalClient structure */
struct _CalClientPrivate {
    /* Load state to avoid multiple loads */
    LoadState load_state;

    /* The calendar factory we are contacting */
    GNOME_Evolution_Calendar_CalFactory factory;

    /* Our calendar listener */
    CalListener *listener;

    /* The calendar client interface object we are contacting */
    GNOME_Evolution_Calendar_Cal cal;
};



/* Signal IDs */
enum {
    CAL_LOADED,
    OBJ_UPDATED,
    OBJ_REMOVED,
    LAST_SIGNAL
};

static void cal_client_class_init (CalClientClass *class);
static void cal_client_init (CalClient *client);
static void cal_client_destroy (GtkObject *object);

static guint cal_client_signals[LAST_SIGNAL];

static GtkObjectClass *parent_class;



/**
 * cal_client_get_type:
 * @void:
 *
 * Registers the #CalClient class if necessary, and returns the type ID assigned
 * to it.
 *
 * Return value: The type ID of the #CalClient class.
 **/
GtkType
cal_client_get_type (void)
{
    static GtkType cal_client_type = 0;

    if (!cal_client_type) {
        static const GtkTypeInfo cal_client_info = {
            "CalClient",
            sizeof (CalClient),
            sizeof (CalClientClass),
            (GtkClassInitFunc) cal_client_class_init,
            (GtkObjectInitFunc) cal_client_init,
            NULL, /* reserved_1 */
            NULL, /* reserved_2 */
            (GtkClassInitFunc) NULL
        };

        cal_client_type = gtk_type_unique (GTK_TYPE_OBJECT, &cal_client_info);
    }

    return cal_client_type;
}

/* Class initialization function for the calendar client */
static void
cal_client_class_init (CalClientClass *class)
{
    GtkObjectClass *object_class;

    object_class = (GtkObjectClass *) class;

    parent_class = gtk_type_class (GTK_TYPE_OBJECT);

    cal_client_signals[CAL_LOADED] =
        gtk_signal_new ("cal_loaded",
                GTK_RUN_FIRST,
                object_class->type,
                GTK_SIGNAL_OFFSET (CalClientClass, cal_loaded),
                gtk_marshal_NONE__ENUM,
                GTK_TYPE_NONE, 1,
                GTK_TYPE_ENUM);
    cal_client_signals[OBJ_UPDATED] =
        gtk_signal_new ("obj_updated",
                GTK_RUN_FIRST,
                object_class->type,
                GTK_SIGNAL_OFFSET (CalClientClass, obj_updated),
                gtk_marshal_NONE__STRING,
                GTK_TYPE_NONE, 1,
                GTK_TYPE_STRING);
    cal_client_signals[OBJ_REMOVED] =
        gtk_signal_new ("obj_removed",
                GTK_RUN_FIRST,
                object_class->type,
                GTK_SIGNAL_OFFSET (CalClientClass, obj_removed),
                gtk_marshal_NONE__STRING,
                GTK_TYPE_NONE, 1,
                GTK_TYPE_STRING);

    gtk_object_class_add_signals (object_class, cal_client_signals, LAST_SIGNAL);

    object_class->destroy = cal_client_destroy;
}

/* Object initialization function for the calendar client */
static void
cal_client_init (CalClient *client)
{
    CalClientPrivate *priv;

    priv = g_new0 (CalClientPrivate, 1);
    client->priv = priv;

    priv->factory = CORBA_OBJECT_NIL;
    priv->load_state = LOAD_STATE_NOT_LOADED;
}

/* Gets rid of the factory that a client knows about */
static void
destroy_factory (CalClient *client)
{
    CalClientPrivate *priv;
    CORBA_Environment ev;
    int result;

    priv = client->priv;

    CORBA_exception_init (&ev);
    result = CORBA_Object_is_nil (priv->factory, &ev);
    if (ev._major != CORBA_NO_EXCEPTION) {
        g_message ("destroy_factory(): could not see if the factory was nil");
        priv->factory = CORBA_OBJECT_NIL;
        CORBA_exception_free (&ev);
        return;
    }
    CORBA_exception_free (&ev);

    if (result)
        return;

    CORBA_exception_init (&ev);
    CORBA_Object_release (priv->factory, &ev);
    if (ev._major != CORBA_NO_EXCEPTION)
        g_message ("destroy_factory(): could not release the factory");

    CORBA_exception_free (&ev);
    priv->factory = CORBA_OBJECT_NIL;
}

/* Gets rid of the listener that a client knows about */
static void
destroy_listener (CalClient *client)
{
    CalClientPrivate *priv;

    priv = client->priv;

    if (!priv->listener)
        return;

    bonobo_object_unref (BONOBO_OBJECT (priv->listener));
    priv->listener = NULL;
}

/* Gets rid of the calendar client interface object that a client knows about */
static void
destroy_cal (CalClient *client)
{
    CalClientPrivate *priv;
    CORBA_Environment ev;
    int result;

    priv = client->priv;

    CORBA_exception_init (&ev);
    result = CORBA_Object_is_nil (priv->cal, &ev);
    if (ev._major != CORBA_NO_EXCEPTION) {
        g_message ("destroy_cal(): could not see if the "
               "calendar client interface object was nil");
        priv->cal = CORBA_OBJECT_NIL;
        CORBA_exception_free (&ev);
        return;
    }
    CORBA_exception_free (&ev);

    if (result)
        return;

    CORBA_exception_init (&ev);
    GNOME_Evolution_Calendar_Cal_unref (priv->cal, &ev);
    if (ev._major != CORBA_NO_EXCEPTION)
        g_message ("destroy_cal(): could not unref the calendar client interface object");

    CORBA_exception_free (&ev);

    CORBA_exception_init (&ev);
    CORBA_Object_release (priv->cal, &ev);
    if (ev._major != CORBA_NO_EXCEPTION)
        g_message ("destroy_cal(): could not release the calendar client interface object");

    CORBA_exception_free (&ev);
    priv->cal = CORBA_OBJECT_NIL;

}

/* Destroy handler for the calendar client */
static void
cal_client_destroy (GtkObject *object)
{
    CalClient *client;
    CalClientPrivate *priv;

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

    client = CAL_CLIENT (object);
    priv = client->priv;

    destroy_factory (client);
    destroy_listener (client);
    destroy_cal (client);

    priv->load_state = LOAD_STATE_NOT_LOADED;

    g_free (priv);
    client->priv = NULL;

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



/* Signal handlers for the listener's signals */

/* Handle the cal_loaded signal from the listener */
static void
cal_loaded_cb (CalListener *listener,
           GNOME_Evolution_Calendar_Listener_LoadStatus status,
           GNOME_Evolution_Calendar_Cal cal,
           gpointer data)
{
    CalClient *client;
    CalClientPrivate *priv;
    CORBA_Environment ev;
    GNOME_Evolution_Calendar_Cal cal_copy;
    CalClientLoadStatus client_status;

    client = CAL_CLIENT (data);
    priv = client->priv;

    g_assert (priv->load_state == LOAD_STATE_LOADING);

    client_status = CAL_CLIENT_LOAD_ERROR;

    switch (status) {
    case GNOME_Evolution_Calendar_Listener_SUCCESS:
        CORBA_exception_init (&ev);
        cal_copy = CORBA_Object_duplicate (cal, &ev);
        if (ev._major != CORBA_NO_EXCEPTION) {
            g_message ("cal_loaded(): could not duplicate the calendar client interface");
            CORBA_exception_free (&ev);
            goto error;
        }
        CORBA_exception_free (&ev);

        priv->cal = cal_copy;
        priv->load_state = LOAD_STATE_LOADED;

        client_status = CAL_CLIENT_LOAD_SUCCESS;
        goto out;

    case GNOME_Evolution_Calendar_Listener_ERROR:
        client_status = CAL_CLIENT_LOAD_ERROR;
        goto error;

    case GNOME_Evolution_Calendar_Listener_IN_USE:
        client_status = CAL_CLIENT_LOAD_IN_USE;
        goto error;

    case GNOME_Evolution_Calendar_Listener_METHOD_NOT_SUPPORTED:
        client_status = CAL_CLIENT_LOAD_METHOD_NOT_SUPPORTED;
        goto error;

    default:
        g_assert_not_reached ();
    }

 error:

    bonobo_object_unref (BONOBO_OBJECT (priv->listener));
    priv->listener = NULL;
    priv->load_state = LOAD_STATE_NOT_LOADED;

 out:

    g_assert (priv->load_state != LOAD_STATE_LOADING);

    gtk_signal_emit (GTK_OBJECT (client), cal_client_signals[CAL_LOADED],
             client_status);
}

/* Handle the obj_updated signal from the listener */
static void
obj_updated_cb (CalListener *listener, const GNOME_Evolution_Calendar_CalObjUID uid, gpointer data)
{
    CalClient *client;

    client = CAL_CLIENT (data);
    gtk_signal_emit (GTK_OBJECT (client), cal_client_signals[OBJ_UPDATED], uid);
}

/* Handle the obj_removed signal from the listener */
static void
obj_removed_cb (CalListener *listener, const GNOME_Evolution_Calendar_CalObjUID uid, gpointer data)
{
    CalClient *client;

    client = CAL_CLIENT (data);
    gtk_signal_emit (GTK_OBJECT (client), cal_client_signals[OBJ_REMOVED], uid);
}



/**
 * cal_client_construct:
 * @client: A calendar client.
 *
 * Constructs a calendar client object by contacting the calendar factory of the
 * calendar server.
 *
 * Return value: The same object as the @client argument, or NULL if the
 * calendar factory could not be contacted.
 **/
CalClient *
cal_client_construct (CalClient *client)
{
    CalClientPrivate *priv;
    GNOME_Evolution_Calendar_CalFactory factory, factory_copy;
    CORBA_Environment ev;
    int result;

    CORBA_exception_init (&ev);
    g_return_val_if_fail (client != NULL, NULL);
    g_return_val_if_fail (IS_CAL_CLIENT (client), NULL);

    priv = client->priv;

    factory = (GNOME_Evolution_Calendar_CalFactory) oaf_activate_from_id (
        "OAFIID:GNOME_Evolution_Wombat_CalendarFactory",
        OAF_FLAG_NO_LOCAL, NULL, &ev);

    result = CORBA_Object_is_nil (factory, &ev);
    if (ev._major != CORBA_NO_EXCEPTION) {
        g_message ("cal_client_construct(): could not see if the factory is NIL");
        CORBA_exception_free (&ev);
        return NULL;
    }
    CORBA_exception_free (&ev);

    if (result) {
        g_message ("cal_client_construct(): could not contact Wombat, "
               "the personal calendar server");
        return NULL;
    }

    CORBA_exception_init (&ev);
    factory_copy = CORBA_Object_duplicate (factory, &ev);

    if (ev._major != CORBA_NO_EXCEPTION) {
        g_message ("cal_client_construct(): could not duplicate the calendar factory");
        CORBA_exception_free (&ev);
        return NULL;
    }
    CORBA_exception_free (&ev);

    priv->factory = factory_copy;
    return client;
}

/**
 * cal_client_new:
 *
 * Creates a new calendar client.  It should be initialized by calling
 * cal_client_load_calendar() or cal_client_create_calendar().
 *
 * Return value: A newly-created calendar client, or NULL if the client could
 * not be constructed because it could not contact the calendar server.
 **/
CalClient *
cal_client_new (void)
{
    CalClient *client;

    client = gtk_type_new (CAL_CLIENT_TYPE);

    if (!cal_client_construct (client)) {
        g_message ("cal_client_new(): could not construct the calendar client");
        gtk_object_unref (GTK_OBJECT (client));
        return NULL;
    }

    return client;
}

/* Issues a load or create request */
static gboolean
load_or_create (CalClient *client, const char *str_uri, gboolean load)
{
    CalClientPrivate *priv;
    GNOME_Evolution_Calendar_Listener corba_listener;
    CORBA_Environment ev;

    g_return_val_if_fail (client != NULL, FALSE);
    g_return_val_if_fail (IS_CAL_CLIENT (client), FALSE);

    priv = client->priv;
    g_return_val_if_fail (priv->load_state == LOAD_STATE_NOT_LOADED, FALSE);

    g_return_val_if_fail (str_uri != NULL, FALSE);

    priv->listener = cal_listener_new ();
    if (!priv->listener) {
        g_message ("load_or_create(): could not create the listener");
        return FALSE;
    }

    gtk_signal_connect (GTK_OBJECT (priv->listener), "cal_loaded",
                GTK_SIGNAL_FUNC (cal_loaded_cb),
                client);
    gtk_signal_connect (GTK_OBJECT (priv->listener), "obj_updated",
                GTK_SIGNAL_FUNC (obj_updated_cb),
                client);
    gtk_signal_connect (GTK_OBJECT (priv->listener), "obj_removed",
                GTK_SIGNAL_FUNC (obj_removed_cb),
                client);

    corba_listener = (GNOME_Evolution_Calendar_Listener) bonobo_object_corba_objref (
        BONOBO_OBJECT (priv->listener));

    CORBA_exception_init (&ev);

    priv->load_state = LOAD_STATE_LOADING;

    if (load)
        GNOME_Evolution_Calendar_CalFactory_load (priv->factory, str_uri, corba_listener, &ev);
    else
        GNOME_Evolution_Calendar_CalFactory_create (priv->factory, str_uri, corba_listener, &ev);

    if (ev._major != CORBA_NO_EXCEPTION) {
        g_message ("load_or_create(): load/create request failed");
        bonobo_object_unref (BONOBO_OBJECT (priv->listener));
        priv->listener = NULL;
        priv->load_state = LOAD_STATE_NOT_LOADED;
        CORBA_exception_free (&ev);
        return FALSE;
    }
    CORBA_exception_free (&ev);

    return TRUE;
}

/**
 * cal_client_load_calendar:
 * @client: A calendar client.
 * @str_uri: URI of calendar to load.
 *
 * Makes a calendar client initiate a request to load a calendar.  The calendar
 * client will emit the "cal_loaded" signal when the response from the server is
 * received.
 *
 * Return value: TRUE on success, FALSE on failure to issue the load request.
 **/
gboolean
cal_client_load_calendar (CalClient *client, const char *str_uri)
{
    return load_or_create (client, str_uri, TRUE);
}

/**
 * cal_client_create_calendar:
 * @client: A calendar client.
 * @str_uri: URI that will contain the calendar data.
 *
 * Makes a calendar client initiate a request to create a new calendar.  The
 * calendar client will emit the "cal_loaded" signal when the response from the
 * server is received.
 *
 * Return value: TRUE on success, FALSE on failure to issue the create request.
 **/
gboolean
cal_client_create_calendar (CalClient *client, const char *str_uri)
{
    return load_or_create (client, str_uri, FALSE);
}

/**
 * cal_client_is_loaded:
 * @client: A calendar client.
 * 
 * Queries whether a calendar client has been loaded successfully.
 * 
 * Return value: TRUE if the client has been loaded, FALSE if it has not or if
 * the loading process is not finished yet.
 **/
gboolean
cal_client_is_loaded (CalClient *client)
{
    CalClientPrivate *priv;

    g_return_val_if_fail (client != NULL, FALSE);
    g_return_val_if_fail (IS_CAL_CLIENT (client), FALSE);

    priv = client->priv;
    return (priv->load_state == LOAD_STATE_LOADED);
}

/* Converts our representation of a calendar component type into its CORBA representation */
static GNOME_Evolution_Calendar_CalObjType
corba_obj_type (CalObjType type)
{
    return (((type & CALOBJ_TYPE_EVENT) ? GNOME_Evolution_Calendar_TYPE_EVENT : 0)
        | ((type & CALOBJ_TYPE_TODO) ? GNOME_Evolution_Calendar_TYPE_TODO : 0)
        | ((type & CALOBJ_TYPE_JOURNAL) ? GNOME_Evolution_Calendar_TYPE_JOURNAL : 0));
}

/**
 * cal_client_get_n_objects:
 * @client: A calendar client.
 * @type: Type of objects that will be counted.
 * 
 * Counts the number of calendar components of the specified @type.  This can be
 * used to count how many events, to-dos, or journals there are, for example.
 * 
 * Return value: Number of components.
 **/
int
cal_client_get_n_objects (CalClient *client, CalObjType type)
{
    CalClientPrivate *priv;
    CORBA_Environment ev;
    int n;
    int t;

    g_return_val_if_fail (client != NULL, -1);
    g_return_val_if_fail (IS_CAL_CLIENT (client), -1);

    priv = client->priv;
    g_return_val_if_fail (priv->load_state == LOAD_STATE_LOADED, -1);

    t = corba_obj_type (type);

    CORBA_exception_init (&ev);
    n = GNOME_Evolution_Calendar_Cal_countObjects (priv->cal, t, &ev);

    if (ev._major != CORBA_NO_EXCEPTION) {
        g_message ("cal_client_get_n_objects(): could not get the number of objects");
        CORBA_exception_free (&ev);
        return -1;
    }

    CORBA_exception_free (&ev);
    return n;
}

/**
 * cal_client_get_object:
 * @client: A calendar client.
 * @uid: Unique identifier for a calendar component.
 * @comp: Return value for the calendar component object.
 *
 * Queries a calendar for a calendar component object based on its unique
 * identifier.
 *
 * Return value: Result code based on the status of the operation.
 **/
CalClientGetStatus
cal_client_get_object (CalClient *client, const char *uid, CalComponent **comp)
{
    CalClientPrivate *priv;
    CORBA_Environment ev;
    GNOME_Evolution_Calendar_CalObj comp_str;
    CalClientGetStatus retval;
    icalcomponent *icalcomp;

    g_return_val_if_fail (client != NULL, CAL_CLIENT_GET_NOT_FOUND);
    g_return_val_if_fail (IS_CAL_CLIENT (client), CAL_CLIENT_GET_NOT_FOUND);

    priv = client->priv;
    g_return_val_if_fail (priv->load_state == LOAD_STATE_LOADED, CAL_CLIENT_GET_NOT_FOUND);

    g_return_val_if_fail (uid != NULL, CAL_CLIENT_GET_NOT_FOUND);
    g_return_val_if_fail (comp != NULL, CAL_CLIENT_GET_NOT_FOUND);

    retval = CAL_CLIENT_GET_NOT_FOUND;
    *comp = NULL;

    CORBA_exception_init (&ev);
    comp_str = GNOME_Evolution_Calendar_Cal_getObject (priv->cal, (char *) uid, &ev);

    if (ev._major == CORBA_USER_EXCEPTION
        && strcmp (CORBA_exception_id (&ev), ex_GNOME_Evolution_Calendar_Cal_NotFound) == 0)
        goto out;
    else if (ev._major != CORBA_NO_EXCEPTION) {
        g_message ("cal_client_get_object(): could not get the object");
        goto out;
    }

    icalcomp = icalparser_parse_string (comp_str);
    CORBA_free (comp_str);

    if (!icalcomp) {
        retval = CAL_CLIENT_GET_SYNTAX_ERROR;
        goto out;
    }

    *comp = cal_component_new ();
    if (!cal_component_set_icalcomponent (*comp, icalcomp)) {
        icalcomponent_free (icalcomp);
        gtk_object_unref (GTK_OBJECT (*comp));
        *comp = NULL;

        retval = CAL_CLIENT_GET_SYNTAX_ERROR;
        goto out;
    }

    retval = CAL_CLIENT_GET_SUCCESS;

 out:

    CORBA_exception_free (&ev);
    return retval;
}

/* Builds an UID list out of a CORBA UID sequence */
static GList *
build_uid_list (GNOME_Evolution_Calendar_CalObjUIDSeq *seq)
{
    GList *uids;
    int i;

    uids = NULL;

    for (i = 0; i < seq->_length; i++)
        uids = g_list_prepend (uids, g_strdup (seq->_buffer[i]));

    return uids;
}

/**
 * cal_client_get_uids:
 * @client: A calendar client.
 * @type: Bitmask with types of objects to return.
 *
 * Queries a calendar for a list of unique identifiers corresponding to calendar
 * objects whose type matches one of the types specified in the @type flags.
 *
 * Return value: A list of strings that are the sought UIDs.
 **/
GList *
cal_client_get_uids (CalClient *client, CalObjType type)
{
    CalClientPrivate *priv;
    CORBA_Environment ev;
    GNOME_Evolution_Calendar_CalObjUIDSeq *seq;
    int t;
    GList *uids;

    g_return_val_if_fail (client != NULL, NULL);
    g_return_val_if_fail (IS_CAL_CLIENT (client), NULL);

    priv = client->priv;
    g_return_val_if_fail (priv->load_state == LOAD_STATE_LOADED, NULL);

    t = corba_obj_type (type);

    CORBA_exception_init (&ev);

    seq = GNOME_Evolution_Calendar_Cal_getUIds (priv->cal, t, &ev);
    if (ev._major != CORBA_NO_EXCEPTION) {
        g_message ("cal_client_get_uids(): could not get the list of UIDs");
        CORBA_exception_free (&ev);
        return NULL;
    }

    CORBA_exception_free (&ev);

    uids = build_uid_list (seq);
    CORBA_free (seq);

    return uids;
}

/* Builds a GList of CalClientChange structures from the CORBA sequence */
static GList *
build_change_list (GNOME_Evolution_Calendar_CalObjChangeSeq *seq)
{
    GList *list = NULL;
    icalcomponent *icalcomp;
    int i;

    /* Create the list in reverse order */
    for (i = 0; i < seq->_length; i++) {
        GNOME_Evolution_Calendar_CalObjChange *corba_coc;
        CalClientChange *ccc;

        corba_coc = &seq->_buffer[i];
        ccc = g_new (CalClientChange, 1);

        icalcomp = icalparser_parse_string (corba_coc->calobj);
        if (!icalcomp)
            continue;

        ccc->comp = cal_component_new ();
        if (!cal_component_set_icalcomponent (ccc->comp, icalcomp)) {
            icalcomponent_free (icalcomp);
            gtk_object_unref (GTK_OBJECT (ccc->comp));
            continue;
        }
        ccc->type = corba_coc->type;

        list = g_list_prepend (list, ccc);
    }

    list = g_list_reverse (list);

    return list;
}

GList *
cal_client_get_changes (CalClient *client, CalObjType type, const char *change_id)
{
    CalClientPrivate *priv;
    CORBA_Environment ev;
    GNOME_Evolution_Calendar_CalObjChangeSeq *seq;
    int t;
    GList *changes;

    g_return_val_if_fail (client != NULL, NULL);
    g_return_val_if_fail (IS_CAL_CLIENT (client), NULL);

    priv = client->priv;
    g_return_val_if_fail (priv->load_state == LOAD_STATE_LOADED, NULL);

    t = corba_obj_type (type);
    CORBA_exception_init (&ev);

    seq = GNOME_Evolution_Calendar_Cal_getChanges (priv->cal, t, change_id, &ev);
    if (ev._major != CORBA_NO_EXCEPTION) {
        g_message ("cal_client_get_changes(): could not get the list of changes");
        CORBA_exception_free (&ev);
        return NULL;
    }

    CORBA_exception_free (&ev);

    changes = build_change_list (seq);
    CORBA_free (seq);

    return changes;
}

/* FIXME: Not used? */
#if 0
/* Builds a GList of CalObjInstance structures from the CORBA sequence */
static GList *
build_object_instance_list (GNOME_Evolution_Calendar_CalObjInstanceSeq *seq)
{
    GList *list;
    int i;

    /* Create the list in reverse order */

    list = NULL;
    for (i = 0; i < seq->_length; i++) {
        GNOME_Evolution_Calendar_CalObjInstance *corba_icoi;
        CalObjInstance *icoi;

        corba_icoi = &seq->_buffer[i];
        icoi = g_new (CalObjInstance, 1);

        icoi->uid = g_strdup (corba_icoi->uid);
        icoi->start = corba_icoi->start;
        icoi->end = corba_icoi->end;

        list = g_list_prepend (list, icoi);
    }

    list = g_list_reverse (list);
    return list;
}
#endif

/**
 * cal_client_get_objects_in_range:
 * @client: A calendar client.
 * @type: Bitmask with types of objects to return.
 * @start: Start time for query.
 * @end: End time for query.
 *
 * Queries a calendar for the objects that occur or recur in the specified range
 * of time.
 *
 * Return value: A list of UID strings.  This should be freed using the
 * cal_obj_uid_list_free() function.
 **/
GList *
cal_client_get_objects_in_range (CalClient *client, CalObjType type, time_t start, time_t end)
{
    CalClientPrivate *priv;
    CORBA_Environment ev;
    GNOME_Evolution_Calendar_CalObjUIDSeq *seq;
    GList *uids;
    int t;

    g_return_val_if_fail (client != NULL, NULL);
    g_return_val_if_fail (IS_CAL_CLIENT (client), NULL);

    priv = client->priv;
    g_return_val_if_fail (priv->load_state == LOAD_STATE_LOADED, NULL);

    g_return_val_if_fail (start != -1 && end != -1, NULL);
    g_return_val_if_fail (start <= end, NULL);

    CORBA_exception_init (&ev);

    t = corba_obj_type (type);

    seq = GNOME_Evolution_Calendar_Cal_getObjectsInRange (priv->cal, t, start, end, &ev);
    if (ev._major != CORBA_NO_EXCEPTION) {
        g_message ("cal_client_get_objects_in_range(): could not get the objects");
        CORBA_exception_free (&ev);
        return NULL;
    }
    CORBA_exception_free (&ev);

    uids = build_uid_list (seq);
    CORBA_free (seq);

    return uids;
}

/* Callback used when an object is updated and we must update the copy we have */
static void
generate_instances_obj_updated_cb (CalClient *client, const char *uid, gpointer data)
{
    GHashTable *uid_comp_hash;
    CalComponent *comp;
    CalClientGetStatus status;
    const char *comp_uid;

    uid_comp_hash = data;

    comp = g_hash_table_lookup (uid_comp_hash, uid);
    if (!comp)
        /* OK, so we don't care about new objects that may indeed be in
         * the requested time range.  We only care about the ones that
         * were returned by the first query to
         * cal_client_get_objects_in_range().
         */
        return;

    g_hash_table_remove (uid_comp_hash, uid);
    gtk_object_unref (GTK_OBJECT (comp));

    status = cal_client_get_object (client, uid, &comp);

    switch (status) {
    case CAL_CLIENT_GET_SUCCESS:
        /* The hash key comes from the component's internal data */
        cal_component_get_uid (comp, &comp_uid);
        g_hash_table_insert (uid_comp_hash, (char *) comp_uid, comp);
        break;

    case CAL_CLIENT_GET_NOT_FOUND:
        /* No longer in the server, too bad */
        break;

    case CAL_CLIENT_GET_SYNTAX_ERROR:
        g_message ("obj_updated_cb(): Syntax error when getting "
               "object `%s'; ignoring...", uid);
        break;
        
    }
}

/* Callback used when an object is removed and we must delete the copy we have */
static void
generate_instances_obj_removed_cb (CalClient *client, const char *uid, gpointer data)
{
    GHashTable *uid_comp_hash;
    CalComponent *comp;

    uid_comp_hash = data;

    comp = g_hash_table_lookup (uid_comp_hash, uid);
    if (!comp)
        return;

    g_hash_table_remove (uid_comp_hash, uid);
    gtk_object_unref (GTK_OBJECT (comp));
}

/* Adds a component to the list; called from g_hash_table_foreach() */
static void
add_component (gpointer key, gpointer value, gpointer data)
{
    CalComponent *comp;
    GList **list;

    comp = CAL_COMPONENT (value);
    list = data;

    *list = g_list_prepend (*list, comp);
}

/* Gets a list of components that recur within the specified range of time.  It
 * ensures that the resulting list of CalComponent objects contains only objects
 * that are actually in the server at the time the initial
 * cal_client_get_objects_in_range() query ends.
 */
static GList *
get_objects_atomically (CalClient *client, CalObjType type, time_t start, time_t end)
{
    GList *uids;
    GHashTable *uid_comp_hash;
    GList *objects;
    guint obj_updated_id;
    guint obj_removed_id;
    GList *l;

    uids = cal_client_get_objects_in_range (client, type, start, end);

    uid_comp_hash = g_hash_table_new (g_str_hash, g_str_equal);

    /* While we are getting the actual object data, keep track of changes */

    obj_updated_id = gtk_signal_connect (GTK_OBJECT (client), "obj_updated",
                         GTK_SIGNAL_FUNC (generate_instances_obj_updated_cb),
                         uid_comp_hash);

    obj_removed_id = gtk_signal_connect (GTK_OBJECT (client), "obj_removed",
                         GTK_SIGNAL_FUNC (generate_instances_obj_removed_cb),
                         uid_comp_hash);

    /* Get the objects */

    for (l = uids; l; l = l->next) {
        CalComponent *comp;
        CalClientGetStatus status;
        char *uid;
        const char *comp_uid;

        uid = l->data;

        status = cal_client_get_object (client, uid, &comp);

        switch (status) {
        case CAL_CLIENT_GET_SUCCESS:
            /* The hash key comes from the component's internal data
             * instead of the duped UID from the list of UIDS.
             */
            cal_component_get_uid (comp, &comp_uid);
            g_hash_table_insert (uid_comp_hash, (char *) comp_uid, comp);
            break;

        case CAL_CLIENT_GET_NOT_FOUND:
            /* Object disappeared from the server, so don't log it */
            break;

        case CAL_CLIENT_GET_SYNTAX_ERROR:
            g_message ("get_objects_atomically(): Syntax error when getting "
                   "object `%s'; ignoring...", uid);
            break;

        default:
            g_assert_not_reached ();
        }
    }

    cal_obj_uid_list_free (uids);

    /* Now our state is consistent with the server, so disconnect from the
     * notification signals and generate the final list of components.
     */

    gtk_signal_disconnect (GTK_OBJECT (client), obj_updated_id);
    gtk_signal_disconnect (GTK_OBJECT (client), obj_removed_id);

    objects = NULL;
    g_hash_table_foreach (uid_comp_hash, add_component, &objects);
    g_hash_table_destroy (uid_comp_hash);

    return objects;
}

struct comp_instance {
    CalComponent *comp;
    time_t start;
    time_t end;
};

/* Called from cal_recur_generate_instances(); adds an instance to the list */
static gboolean
add_instance (CalComponent *comp, time_t start, time_t end, gpointer data)
{
    GList **list;
    struct comp_instance *ci;

    list = data;

    ci = g_new (struct comp_instance, 1);

    ci->comp = comp;
    gtk_object_ref (GTK_OBJECT (ci->comp));
    
    ci->start = start;
    ci->end = end;

    *list = g_list_prepend (*list, ci);

    return TRUE;
}

/* Used from g_list_sort(); compares two struct comp_instance structures */
static gint
compare_comp_instance (gconstpointer a, gconstpointer b)
{
    const struct comp_instance *cia, *cib;
    time_t diff;

    cia = a;
    cib = b;

    diff = cia->start - cib->start;
    return (diff < 0) ? -1 : (diff > 0) ? 1 : 0;
}

/**
 * cal_client_generate_instances:
 * @client: A calendar client.
 * @type: Bitmask with types of objects to return.
 * @start: Start time for query.
 * @end: End time for query.
 * @cb: Callback for each generated instance.
 * @cb_data: Closure data for the callback.
 * 
 * Does a combination of cal_client_get_objects_in_range() and
 * cal_recur_generate_instances().  It fetches the list of objects in an atomic
 * way so that the generated instances are actually in the server at the time
 * the initial cal_client_get_objects_in_range() query ends.
 *
 * The callback function should do a gtk_object_ref() of the calendar component
 * it gets passed if it intends to keep it around.
 **/
void
cal_client_generate_instances (CalClient *client, CalObjType type,
                   time_t start, time_t end,
                   CalRecurInstanceFn cb, gpointer cb_data)
{
    CalClientPrivate *priv;
    GList *objects;
    GList *instances;
    GList *l;

    g_return_if_fail (client != NULL);
    g_return_if_fail (IS_CAL_CLIENT (client));

    priv = client->priv;
    g_return_if_fail (priv->load_state == LOAD_STATE_LOADED);

    g_return_if_fail (start != -1 && end != -1);
    g_return_if_fail (start <= end);
    g_return_if_fail (cb != NULL);

    /* Generate objects */

    objects = get_objects_atomically (client, type, start, end);
    instances = NULL;

    for (l = objects; l; l = l->next) {
        CalComponent *comp;

        comp = l->data;
        cal_recur_generate_instances (comp, start, end, add_instance, &instances);
        gtk_object_unref (GTK_OBJECT (comp));
    }

    g_list_free (objects);

    /* Generate instances and spew them out */

    instances = g_list_sort (instances, compare_comp_instance);

    for (l = instances; l; l = l->next) {
        struct comp_instance *ci;
        gboolean result;
        
        ci = l->data;
        
        result = (* cb) (ci->comp, ci->start, ci->end, cb_data);

        if (!result)
            break;
    }

    /* Clean up */

    for (l = instances; l; l = l->next) {
        struct comp_instance *ci;

        ci = l->data;
        gtk_object_unref (GTK_OBJECT (ci->comp));
        g_free (ci);
    }

    g_list_free (instances);
}

/* Builds a list of CalAlarmInstance structures */
static GSList *
build_alarm_instance_list (CalComponent *comp, GNOME_Evolution_Calendar_CalAlarmInstanceSeq *seq)
{
    GSList *alarms;
    int i;

    alarms = NULL;

    for (i = 0; i < seq->_length; i++) {
        GNOME_Evolution_Calendar_CalAlarmInstance *corba_instance;
        CalComponentAlarm *alarm;
        const char *auid;
        CalAlarmInstance *instance;

        corba_instance = seq->_buffer + i;

        /* Since we want the in-commponent auid, we look for the alarm
         * in the component and fetch its "real" auid.
         */

        alarm = cal_component_get_alarm (comp, corba_instance->auid);
        if (!alarm)
            continue;

        auid = cal_component_alarm_get_uid (alarm);
        cal_component_alarm_free (alarm);

        instance = g_new (CalAlarmInstance, 1);
        instance->auid = auid;
        instance->trigger = corba_instance->trigger;
        instance->occur = corba_instance->occur;

        alarms = g_slist_prepend (alarms, instance);
    }

    return g_slist_reverse (alarms);
}

/* Builds a list of CalComponentAlarms structures */
static GSList *
build_component_alarms_list (GNOME_Evolution_Calendar_CalComponentAlarmsSeq *seq)
{
    GSList *comp_alarms;
    int i;

    comp_alarms = NULL;

    for (i = 0; i < seq->_length; i++) {
        GNOME_Evolution_Calendar_CalComponentAlarms *corba_alarms;
        CalComponent *comp;
        CalComponentAlarms *alarms;
        icalcomponent *icalcomp;

        corba_alarms = seq->_buffer + i;

        icalcomp = icalparser_parse_string (corba_alarms->calobj);
        if (!icalcomp)
            continue;

        comp = cal_component_new ();
        if (!cal_component_set_icalcomponent (comp, icalcomp)) {
            icalcomponent_free (icalcomp);
            gtk_object_unref (GTK_OBJECT (comp));
            continue;
        }

        alarms = g_new (CalComponentAlarms, 1);
        alarms->comp = comp;
        alarms->alarms = build_alarm_instance_list (comp, &corba_alarms->alarms);

        comp_alarms = g_slist_prepend (comp_alarms, alarms);
    }

    return comp_alarms;
}

/**
 * cal_client_get_alarms_in_range:
 * @client: A calendar client.
 * @start: Start time for query.
 * @end: End time for query.
 *
 * Queries a calendar for the alarms that trigger in the specified range of
 * time.
 *
 * Return value: A list of #CalComponentAlarms structures.  This should be freed
 * using the cal_client_free_alarms() function.
 **/
GSList *
cal_client_get_alarms_in_range (CalClient *client, time_t start, time_t end)
{
    CalClientPrivate *priv;
    CORBA_Environment ev;
    GNOME_Evolution_Calendar_CalComponentAlarmsSeq *seq;
    GSList *alarms;

    g_return_val_if_fail (client != NULL, NULL);
    g_return_val_if_fail (IS_CAL_CLIENT (client), NULL);

    priv = client->priv;
    g_return_val_if_fail (priv->load_state == LOAD_STATE_LOADED, NULL);

    g_return_val_if_fail (start != -1 && end != -1, NULL);
    g_return_val_if_fail (start <= end, NULL);

    CORBA_exception_init (&ev);

    seq = GNOME_Evolution_Calendar_Cal_getAlarmsInRange (priv->cal, start, end, &ev);
    if (ev._major != CORBA_NO_EXCEPTION) {
        g_message ("cal_client_get_alarms_in_range(): could not get the alarm range");
        CORBA_exception_free (&ev);
        return NULL;
    }
    CORBA_exception_free (&ev);

    alarms = build_component_alarms_list (seq);
    CORBA_free (seq);

    return alarms;
}

/**
 * cal_client_free_alarms:
 * @comp_alarms: A list of #CalComponentAlarms structures.
 * 
 * Frees a list of #CalComponentAlarms structures as returned by
 * cal_client_get_alarms_in_range().
 **/
void
cal_client_free_alarms (GSList *comp_alarms)
{
    GSList *l;

    for (l = comp_alarms; l; l = l->next) {
        CalComponentAlarms *alarms;

        alarms = l->data;
        g_assert (alarms != NULL);

        cal_component_alarms_free (alarms);
    }

    g_slist_free (comp_alarms);
}

/**
 * cal_client_get_alarms_for_object:
 * @client: A calendar client.
 * @uid: Unique identifier for a calendar component.
 * @start: Start time for query.
 * @end: End time for query.
 * @alarms: Return value for the component's alarm instances.  Will return NULL
 * if no instances occur within the specified time range.  This should be freed
 * using the cal_component_alarms_free() function.
 *
 * Queries a calendar for the alarms of a particular object that trigger in the
 * specified range of time.
 *
 * Return value: TRUE on success, FALSE if the object was not found.
 **/
gboolean
cal_client_get_alarms_for_object (CalClient *client, const char *uid,
                  time_t start, time_t end,
                  CalComponentAlarms **alarms)
{
    CalClientPrivate *priv;
    CORBA_Environment ev;
    GNOME_Evolution_Calendar_CalComponentAlarms *corba_alarms;
    gboolean retval;
    icalcomponent *icalcomp;
    CalComponent *comp;

    g_return_val_if_fail (client != NULL, FALSE);
    g_return_val_if_fail (IS_CAL_CLIENT (client), FALSE);

    priv = client->priv;
    g_return_val_if_fail (priv->load_state == LOAD_STATE_LOADED, FALSE);

    g_return_val_if_fail (uid != NULL, FALSE);
    g_return_val_if_fail (start != -1 && end != -1, FALSE);
    g_return_val_if_fail (start <= end, FALSE);
    g_return_val_if_fail (alarms != NULL, FALSE);

    *alarms = NULL;
    retval = FALSE;

    CORBA_exception_init (&ev);

    corba_alarms = GNOME_Evolution_Calendar_Cal_getAlarmsForObject (priv->cal, (char *) uid,
                                    start, end, &ev);
    if (ev._major == CORBA_USER_EXCEPTION
        && strcmp (CORBA_exception_id (&ev), ex_GNOME_Evolution_Calendar_Cal_NotFound) == 0)
        goto out;
    else if (ev._major != CORBA_NO_EXCEPTION) {
        g_message ("cal_client_get_alarms_for_object(): could not get the alarm range");
        goto out;
    }

    icalcomp = icalparser_parse_string (corba_alarms->calobj);
    if (!icalcomp)
        goto out;

    comp = cal_component_new ();
    if (!cal_component_set_icalcomponent (comp, icalcomp)) {
        icalcomponent_free (icalcomp);
        gtk_object_unref (GTK_OBJECT (comp));
        goto out;
    }

    retval = TRUE;

    *alarms = g_new (CalComponentAlarms, 1);
    (*alarms)->comp = comp;
    (*alarms)->alarms = build_alarm_instance_list (comp, &corba_alarms->alarms);
    CORBA_free (corba_alarms);

 out:
    CORBA_exception_free (&ev);
    return retval;
}

/**
 * cal_client_update_object:
 * @client: A calendar client.
 * @comp: A calendar component object.
 *
 * Asks a calendar to update a component.  Any existing component with the
 * specified component's UID will be replaced.  The client program should not
 * assume that the object is actually in the server's storage until it has
 * received the "obj_updated" notification signal.
 *
 * Return value: TRUE on success, FALSE on specifying an invalid component.
 **/
gboolean
cal_client_update_object (CalClient *client, CalComponent *comp)
{
    CalClientPrivate *priv;
    CORBA_Environment ev;
    gboolean retval;
    char *obj_string;
    const char *uid;

    g_return_val_if_fail (client != NULL, FALSE);
    g_return_val_if_fail (IS_CAL_CLIENT (client), FALSE);

    priv = client->priv;
    g_return_val_if_fail (priv->load_state == LOAD_STATE_LOADED, FALSE);

    g_return_val_if_fail (comp != NULL, FALSE);

    retval = FALSE;

    cal_component_commit_sequence (comp);
    obj_string = cal_component_get_as_string (comp);

    cal_component_get_uid (comp, &uid);

    CORBA_exception_init (&ev);
    GNOME_Evolution_Calendar_Cal_updateObject (priv->cal, (char *) uid, obj_string, &ev);
    g_free (obj_string);

    if (ev._major == CORBA_USER_EXCEPTION &&
        strcmp (CORBA_exception_id (&ev), ex_GNOME_Evolution_Calendar_Cal_InvalidObject) == 0)
        goto out;
    else if (ev._major != CORBA_NO_EXCEPTION) {
        g_message ("cal_client_update_object(): could not update the object");
        goto out;
    }

    retval = TRUE;

 out:
    CORBA_exception_free (&ev);
    return retval;
}

/**
 * cal_client_remove_object:
 * @client: A calendar client.
 * @uid: Unique identifier of the calendar component to remove.
 * 
 * Asks a calendar to remove a component.  If the server is able to remove the
 * component, all clients will be notified and they will emit the "obj_removed"
 * signal.
 * 
 * Return value: TRUE on success, FALSE on specifying a UID for a component that
 * is not in the server.  Returning FALSE is normal; the object may have
 * disappeared from the server before the client has had a chance to receive the
 * corresponding notification.
 **/
gboolean
cal_client_remove_object (CalClient *client, const char *uid)
{
    CalClientPrivate *priv;
    CORBA_Environment ev;
    gboolean retval;

    g_return_val_if_fail (client != NULL, FALSE);
    g_return_val_if_fail (IS_CAL_CLIENT (client), FALSE);

    priv = client->priv;
    g_return_val_if_fail (priv->load_state == LOAD_STATE_LOADED, FALSE);

    g_return_val_if_fail (uid != NULL, FALSE);

    retval = FALSE;

    CORBA_exception_init (&ev);
    GNOME_Evolution_Calendar_Cal_removeObject (priv->cal, (char *) uid, &ev);

    if (ev._major == CORBA_USER_EXCEPTION &&
        strcmp (CORBA_exception_id (&ev), ex_GNOME_Evolution_Calendar_Cal_NotFound) == 0)
        goto out;
    else if (ev._major != CORBA_NO_EXCEPTION) {
        g_message ("cal_client_remove_object(): could not remove the object");
        goto out;
    }

    retval = TRUE;

 out:
    CORBA_exception_free (&ev);
    return retval;
}