source: trunk/third/bonobo/bonobo/bonobo-plug.c @ 16855

/* Bonobo-Plug.c: A private version of GtkPlug
 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the Free
 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/* By Owen Taylor <otaylor@gtk.org>              98/4/4 */

/*
 * Modified by the GTK+ Team and others 1997-1999.  See the AUTHORS
 * file for a list of people on the GTK+ Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GTK+ at ftp://ftp.gtk.org/pub/gtk/.
 */

#include <stdio.h>
#include "gdk/gdkx.h"
#include "gdk/gdkkeysyms.h"
#include "bonobo/bonobo-plug.h"



/* Private part of the BonoboPlug structure */
struct _BonoboPlugPrivate {
        GdkWindow *socket_window;
        gint same_app;

        /* The control interface that holds us */
        BonoboControl *control;

        /*
         * Whether we have the focus.  We cannot use the GTK_HAS_FOCUS flag
         * because we are not a GTK_CAN_FOCUS widget and it would make
         * GtkContainer::focus() skip us immediately when trying to change the
         * focus within the plug's children.
         */
        guint has_focus : 1;
};

/* From Tk */
#define EMBEDDED_APP_WANTS_FOCUS NotifyNormal+20

/* Sometimes we have to forward keyboard events to our parent socket because
 * they get received on the plug side when the plug does not have the focus, or
 * because no widget within the plug handled the event and we must propagate it
 * upwards.  However, since we are using XSendEvent(), we have to use the
 * original keycode and state values for the synthetic event.  GDK translates
 * these and we cannot recover them from a GTK+ widget keyboard handler.  So we
 * install an event filter for all keyboard events, ignore those that are not
 * for plug windows, and store the remaining ones in this table, which is a
 * circular buffer.  The table is keyed by the timestamps of the events.  When
 * we have to forward a key event, we fetch the original values from this table.
 */
#define KEY_EVENT_TABLE_SIZE 20

struct KeyEvent {
        guint32 time;
        guint keycode;
        guint state;
};

struct KeyEvent key_event_table[KEY_EVENT_TABLE_SIZE];

/* The table is a circular buffer.  Events get inserted at the tail, get removed
 * from the head.
 */
static int key_event_table_head;
static int key_event_table_tail;
static int key_event_table_nelements;


static GtkWindowClass *parent_class = NULL;

static void install_filter (GdkWindow *window);



/**
 * bonobo_plug_construct:
 * @plug: The #BonoboPlug.
 * @socket_id: the XID of the socket's window.
 *
 * Finish the creation of a #BonoboPlug widget. This function
 * will generally only be used by classes deriving
 * from #BonoboPlug.
 */
void
bonobo_plug_construct (BonoboPlug *plug, guint32 socket_id)
{
        BonoboPlugPrivate *priv;

        g_return_if_fail (plug != NULL);
        g_return_if_fail (BONOBO_IS_PLUG (plug));

        priv = plug->priv;

        priv->socket_window = gdk_window_lookup (socket_id);
        priv->same_app = TRUE;

        if (priv->socket_window == NULL) {
                priv->socket_window = gdk_window_foreign_new (socket_id);
                priv->same_app = FALSE;
        }
}

/**
 * bonobo_plug_new:
 * @socket_id: the XID of the socket's window.
 *
 * Create a new plug widget inside the #GtkSocket identified
 * by @socket_id.
 *
 * Returns: the new #BonoboPlug widget.
 */
GtkWidget*
bonobo_plug_new (guint32 socket_id)
{
        BonoboPlug *plug;

        plug = BONOBO_PLUG (gtk_type_new (bonobo_plug_get_type ()));
        bonobo_plug_construct (plug, socket_id);
        return GTK_WIDGET (plug);
}

/* Destroy handler for the plug widget */
static void
bonobo_plug_destroy (GtkObject *object)
{
        BonoboPlug *plug;
        BonoboPlugPrivate *priv;

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

        plug = BONOBO_PLUG (object);
        priv = plug->priv;

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

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

static void
bonobo_plug_unrealize (GtkWidget *widget)
{
        BonoboPlug *plug;
        BonoboPlugPrivate *priv;

        g_return_if_fail (widget != NULL);
        g_return_if_fail (BONOBO_IS_PLUG (widget));

        plug = BONOBO_PLUG (widget);
        priv = plug->priv;

        if (GTK_WIDGET_CLASS (parent_class)->unrealize)
                (* GTK_WIDGET_CLASS (parent_class)->unrealize) (widget);

        if (priv->socket_window != NULL) {
                gdk_window_set_user_data (priv->socket_window, NULL);
                gdk_window_unref (priv->socket_window);
                priv->socket_window = NULL;
        }
}

/* Checks whether a window is a descendant of a plug window. */
static gboolean
is_descendant_window_of_plug (GdkWindow *window)
{
        while (window) {
                GtkWidget *widget;

                widget = window->user_data;
                if (widget && BONOBO_IS_PLUG (widget))
                        return TRUE;

                window = gdk_window_get_parent (window);
        }

        return FALSE;
}

/* Filter function for all events.  See the comments for key_event_table above.
 * We filter key events and log them in the key_event_table, and we take care
 * of child window creations.
 */
static GdkFilterReturn
event_filter_cb (GdkXEvent *xevent, GdkEvent *event, gpointer data)
{
        XEvent *xev;
        struct KeyEvent *ke;
        GdkWindow *w;

        xev = (XEvent *) xevent;

        /* Ignore non-keyboard events */
        if (!(xev->type == KeyPress || xev->type == KeyRelease || xev->type == CreateNotify))
                return GDK_FILTER_CONTINUE;

        if (!is_descendant_window_of_plug (gdk_window_lookup (xev->xany.window)))
                return GDK_FILTER_CONTINUE;

        switch (xev->type) {
        case KeyPress:
        case KeyRelease:
                ke = key_event_table + key_event_table_tail;

                ke->time = xev->xkey.time;
                ke->keycode = xev->xkey.keycode;
                ke->state = xev->xkey.state;

                /* We just overwrite the oldest entries if the table becomes full */

                if (key_event_table_tail == key_event_table_head) {
                        if (key_event_table_nelements == 0)
                                key_event_table_nelements = 1;
                        else {
                                g_assert (key_event_table_nelements == KEY_EVENT_TABLE_SIZE);

                                key_event_table_head++;
                                if (key_event_table_head == KEY_EVENT_TABLE_SIZE)
                                        key_event_table_head = 0;
                        }

                        key_event_table_tail++;
                        if (key_event_table_tail == KEY_EVENT_TABLE_SIZE)
                                key_event_table_tail = 0;
                } else {
                        key_event_table_tail++;
                        if (key_event_table_tail == KEY_EVENT_TABLE_SIZE)
                                key_event_table_tail = 0;

                        key_event_table_nelements++;
                        g_assert (key_event_table_nelements <= KEY_EVENT_TABLE_SIZE);
                }

                return GDK_FILTER_CONTINUE;

        case CreateNotify:
                w = gdk_window_lookup (xev->xcreatewindow.window);
                if (w)
                        install_filter (w);

                return GDK_FILTER_CONTINUE;

        default:
                g_assert_not_reached ();
                return GDK_FILTER_CONTINUE;
        }
}

/* Recursively sets up the key event filter for the specified window and all its
 * children.
 */
static void
install_filter (GdkWindow *window)
{
        GList *children;
        GList *l;
        Window xwindow;
        XWindowAttributes attr;

        gdk_window_add_filter (window, event_filter_cb, NULL);

        /* Add SubstructureNotifyMask so that we can monitor for child window creations */

        xwindow = GDK_WINDOW_XWINDOW (window);
        if (XGetWindowAttributes (GDK_DISPLAY (), xwindow, &attr) == Success)
                XSelectInput (GDK_DISPLAY (), xwindow, attr.your_event_mask | SubstructureNotifyMask);

        /* Add filters for all the children */

        children = gdk_window_get_children (window);

        for (l = children; l; l = l->next) {
                GdkWindow *w;

                w = l->data;
                install_filter (w);
        }

        g_list_free (children);
}

/* map handler for the plug widget.  We install the key event filter for all of
 * our child windows here, ugh.
 */
static void
bonobo_plug_map (GtkWidget *widget)
{
        if (GTK_WIDGET_CLASS (parent_class)->map)
                (* GTK_WIDGET_CLASS (parent_class)->map) (widget);

        install_filter (widget->window);
}

static void
bonobo_plug_realize (GtkWidget *widget)
{
        BonoboPlug *plug;
        BonoboPlugPrivate *priv;
        GtkWindow *window;
        GdkWindowAttr attributes;
        gint attributes_mask;

        g_return_if_fail (widget != NULL);
        g_return_if_fail (BONOBO_IS_PLUG (widget));

        plug = BONOBO_PLUG (widget);
        priv = plug->priv;

        GTK_WIDGET_SET_FLAGS (widget, GTK_REALIZED);
        window = GTK_WINDOW (widget);

        attributes.window_type = GDK_WINDOW_CHILD;      /* XXX GDK_WINDOW_PLUG ? */
        attributes.title = window->title;
        attributes.wmclass_name = window->wmclass_name;
        attributes.wmclass_class = window->wmclass_class;
        attributes.width = widget->allocation.width;
        attributes.height = widget->allocation.height;
        attributes.wclass = GDK_INPUT_OUTPUT;

        /*
         * this isn't right - we should match our parent's visual/colormap.
         * though that will require handling "foreign" colormaps
         */
        attributes.visual = gtk_widget_get_visual (widget);
        attributes.colormap = gtk_widget_get_colormap (widget);
        attributes.event_mask = gtk_widget_get_events (widget);
        attributes.event_mask |= (GDK_EXPOSURE_MASK |
                                  GDK_KEY_PRESS_MASK |
                                  GDK_ENTER_NOTIFY_MASK |
                                  GDK_LEAVE_NOTIFY_MASK |
                                  GDK_FOCUS_CHANGE_MASK |
                                  GDK_STRUCTURE_MASK);

        attributes_mask = GDK_WA_VISUAL | GDK_WA_COLORMAP;
        attributes_mask |= (window->title ? GDK_WA_TITLE : 0);
        attributes_mask |= (window->wmclass_name ? GDK_WA_WMCLASS : 0);

        gdk_error_trap_push ();
        widget->window = gdk_window_new (priv->socket_window,
                                         &attributes, attributes_mask);
        gdk_flush ();
        if (gdk_error_trap_pop ()) {
                /* Uh-oh */
                gdk_error_trap_push ();
                gdk_window_destroy (widget->window);
                gdk_flush ();
                gdk_error_trap_pop ();
                widget->window = gdk_window_new (NULL, &attributes, attributes_mask);
        }

        ((GdkWindowPrivate *)widget->window)->window_type = GDK_WINDOW_TOPLEVEL;
        gdk_window_set_user_data (widget->window, window);

        widget->style = gtk_style_attach (widget->style, widget->window);
        gtk_style_set_background (widget->style, widget->window, GTK_STATE_NORMAL);
}

/* Looks up a KeyEvent structure in the key event table based on the timestamp
 * of the specified event.  If it is not found, returns NULL.
 */
static struct KeyEvent *
lookup_key_event (GdkEventKey *event)
{
        int i;

        if (key_event_table_nelements == 0)
                return NULL;

        i = key_event_table_head;

        while (key_event_table_nelements > 0) {
                key_event_table_head++;
                if (key_event_table_head == KEY_EVENT_TABLE_SIZE)
                        key_event_table_head = 0;

                key_event_table_nelements--;

                if (key_event_table[i].time == event->time)
                        return key_event_table + i;
        }

        return NULL;
}

/* Extracts a key event from the key event table and forwards it to our parent
 * socket.
 */
static void
bonobo_plug_forward_key_event (BonoboPlug *plug, GdkEventKey *event)
{
        BonoboPlugPrivate *priv;
        XEvent xevent;
        struct KeyEvent *ke;

        priv = plug->priv;

        if (event->type == GDK_KEY_PRESS)
                xevent.xkey.type = KeyPress;
        else if (event->type == GDK_KEY_RELEASE)
                xevent.xkey.type = KeyRelease;
        else
                g_assert_not_reached ();

        xevent.xkey.display = GDK_WINDOW_XDISPLAY (GTK_WIDGET(plug)->window);
        xevent.xkey.window = GDK_WINDOW_XWINDOW (priv->socket_window);
        xevent.xkey.root = GDK_ROOT_WINDOW (); /* FIXME */
        xevent.xkey.time = event->time;
        xevent.xkey.x = 0;
        xevent.xkey.y = 0;
        xevent.xkey.x_root = 0;
        xevent.xkey.y_root = 0;
        xevent.xkey.same_screen = TRUE; /* FIXME ? */

        ke = lookup_key_event (event);
        if (ke) {
                xevent.xkey.keycode = ke->keycode;
                xevent.xkey.state = ke->state;
        } else {
                /* Do the best we can do at this point, even if we may lose
                 * information from the original event.
                 */
                xevent.xkey.state = event->state;
                xevent.xkey.keycode = XKeysymToKeycode(GDK_DISPLAY(), event->keyval);
        }

        gdk_error_trap_push ();
        XSendEvent (gdk_display,
                    GDK_WINDOW_XWINDOW (priv->socket_window),
                    False, NoEventMask, &xevent);
        gdk_flush ();
        gdk_error_trap_pop ();
}

/* Key_press_event handler for the plug widget */
static gint
bonobo_plug_key_press_event (GtkWidget *widget, GdkEventKey *event)
{
        BonoboPlug *plug;
        BonoboPlugPrivate *priv;
        GtkContainer *container;
        GtkWindow *window;
        GtkDirectionType direction = 0;
        gint return_val;

        g_return_val_if_fail (widget != NULL, FALSE);
        g_return_val_if_fail (BONOBO_IS_PLUG (widget), FALSE);
        g_return_val_if_fail (event != NULL, FALSE);

        plug = BONOBO_PLUG (widget);
        priv = plug->priv;

        container = GTK_CONTAINER (widget);
        window = GTK_WINDOW (widget);

        if (!GTK_WIDGET_HAS_FOCUS (widget)) {
                bonobo_plug_forward_key_event (plug, event);
                return FALSE;
        }

        return_val = FALSE;
        if (window->focus_widget
            && window->focus_widget != widget
            && GTK_WIDGET_IS_SENSITIVE (window->focus_widget))
                return_val = gtk_widget_event (window->focus_widget, (GdkEvent*) event);

        if (!return_val)
                switch (event->keyval) {
                case GDK_space:
                        if (window->focus_widget) {
                                if (GTK_WIDGET_IS_SENSITIVE (window->focus_widget))
                                        return_val = gtk_widget_activate (window->focus_widget);
                        }
                        break;

                case GDK_Return:
                case GDK_KP_Enter:
                        if (window->default_widget && GTK_WIDGET_IS_SENSITIVE (window->default_widget)
                            && (!window->focus_widget
                                || !GTK_WIDGET_RECEIVES_DEFAULT (window->focus_widget)))
                                return_val = gtk_widget_activate (window->default_widget);
                        else if (window->focus_widget) {
                                if (GTK_WIDGET_IS_SENSITIVE (window->focus_widget))
                                        return_val = gtk_widget_activate (window->focus_widget);
                        }
                        break;

                case GDK_Up:
                case GDK_Down:
                case GDK_Left:
                case GDK_Right:
                case GDK_KP_Up:
                case GDK_KP_Down:
                case GDK_KP_Left:
                case GDK_KP_Right:
                case GDK_Tab:
                case GDK_ISO_Left_Tab:
                        switch (event->keyval) {
                        case GDK_Up:
                        case GDK_KP_Up:
                                direction = GTK_DIR_UP;
                                break;
                        case GDK_Down:
                        case GDK_KP_Down:
                                direction = GTK_DIR_DOWN;
                                break;
                        case GDK_Left:
                        case GDK_KP_Left:
                                direction = GTK_DIR_LEFT;
                                break;
                        case GDK_Right:
                        case GDK_KP_Right:
                                direction = GTK_DIR_RIGHT;
                                break;
                        case GDK_Tab:
                        case GDK_ISO_Left_Tab:
                                if (event->state & GDK_SHIFT_MASK)
                                        direction = GTK_DIR_TAB_BACKWARD;
                                else
                                        direction = GTK_DIR_TAB_FORWARD;
                                break;
                        default:
                                direction = GTK_DIR_UP; /* never reached, but makes compiler happy */
                        }

                        gtk_container_focus (container, direction);

                        if (!container->focus_child) {
                                gtk_window_set_focus (window, NULL);

                                gdk_error_trap_push ();
                                XSetInputFocus (GDK_DISPLAY (),
                                                GDK_WINDOW_XWINDOW (priv->socket_window),
                                                RevertToParent, event->time);
                                gdk_flush ();
                                gdk_error_trap_pop ();

                                bonobo_plug_forward_key_event (plug, event);
                        }

                        return_val = TRUE;
                        break;
                }

        /*
         * If we havn't handled it pass it on to our socket, since it might be a
         * keybinding or something interesting.
         */
        if (!return_val)
                bonobo_plug_forward_key_event (plug, event);

        return return_val;
}

/* Key_release_event handler for the plug widget */
static gint
bonobo_plug_key_release_event (GtkWidget *widget, GdkEventKey *event)
{
        BonoboPlug *plug;
        GtkWindow *window;
        gint return_val;

        g_return_val_if_fail (widget != NULL, FALSE);
        g_return_val_if_fail (BONOBO_IS_PLUG (widget), FALSE);
        g_return_val_if_fail (event != NULL, FALSE);

        plug = BONOBO_PLUG (widget);

        if (!GTK_WIDGET_HAS_FOCUS (widget)) {
                bonobo_plug_forward_key_event (plug, event);
                return FALSE;
        }

        window = GTK_WINDOW (widget);

        return_val = FALSE;
        if (window->focus_widget
            && window->focus_widget != widget
            && GTK_WIDGET_IS_SENSITIVE (window->focus_widget))
                return_val = gtk_widget_event (window->focus_widget, (GdkEvent*) event);

        /*
         * If we havn't handled it pass it on to our socket, since it might be a
         * keybinding or something interesting.
         */
        if (!return_val)
                bonobo_plug_forward_key_event (plug, event);

        return return_val;
}

/* Focus_in_event handler for the plug widget */
static gint
bonobo_plug_focus_in_event (GtkWidget *widget, GdkEventFocus *event)
{
        GtkWindow *window;
        GdkEventFocus fevent;

        g_return_val_if_fail (widget != NULL, FALSE);
        g_return_val_if_fail (BONOBO_IS_PLUG (widget), FALSE);
        g_return_val_if_fail (event != NULL, FALSE);

        /*
         * It appears spurious focus in events can occur when the window is
         * hidden. So we'll just check to see if the window is visible before
         * actually handling the event.
         */
        if (GTK_WIDGET_VISIBLE (widget)) {
                GTK_OBJECT_SET_FLAGS (widget, GTK_HAS_FOCUS);

                window = GTK_WINDOW (widget);
                if (window->focus_widget && !GTK_WIDGET_HAS_FOCUS (window->focus_widget)) {
                        fevent.type = GDK_FOCUS_CHANGE;
                        fevent.window = window->focus_widget->window;
                        fevent.in = TRUE;

                        gtk_widget_event (window->focus_widget, (GdkEvent*) &fevent);
                }
        }

        return FALSE;
}

/* Focus_out_event handler for the plug widget */
static gint
bonobo_plug_focus_out_event (GtkWidget *widget, GdkEventFocus *event)
{
        GtkWindow *window;
        GdkEventFocus fevent;

        g_return_val_if_fail (widget != NULL, FALSE);
        g_return_val_if_fail (BONOBO_IS_PLUG (widget), FALSE);
        g_return_val_if_fail (event != NULL, FALSE);

        window = GTK_WINDOW (widget);

        GTK_OBJECT_UNSET_FLAGS (widget, GTK_HAS_FOCUS);

        if (window->focus_widget && GTK_WIDGET_HAS_FOCUS (window->focus_widget)) {
                fevent.type = GDK_FOCUS_CHANGE;
                fevent.window = window->focus_widget->window;
                fevent.in = FALSE;

                gtk_widget_event (window->focus_widget, (GdkEvent*) &fevent);
        }

        return FALSE;
}

/*
 * Focus handler for the plug widget.  It should be the same as GtkWindow's, but
 * it should not wrap around if we reach the `last' widget so that we can pass
 * on the focus request to the parent.
 */
static gint
bonobo_plug_focus (GtkContainer *container, GtkDirectionType direction)
{
        BonoboPlug *plug;
        BonoboPlugPrivate *priv;
        GtkWindow *window;
        GtkBin *bin;
        GtkWidget *old_focus_child;

        plug = BONOBO_PLUG (container);
        priv = plug->priv;

        window = GTK_WINDOW (container);
        bin = GTK_BIN (container);

        old_focus_child = container->focus_child;

        if (old_focus_child) {
                if (GTK_IS_CONTAINER (old_focus_child)
                    && GTK_WIDGET_DRAWABLE (old_focus_child)
                    && GTK_WIDGET_IS_SENSITIVE (old_focus_child)
                    && gtk_container_focus (GTK_CONTAINER (old_focus_child), direction))
                        return TRUE;
        }

        if (window->focus_widget) {
                GtkWidget *parent;

                parent = window->focus_widget->parent;
                while (parent) {
                        gtk_container_set_focus_child (GTK_CONTAINER (parent), NULL);
                        parent = parent->parent;
                }

                gtk_window_set_focus (window, NULL);
                return FALSE;
        }

        if (GTK_WIDGET_DRAWABLE (bin->child) && GTK_WIDGET_IS_SENSITIVE (bin->child)) {
                if (GTK_IS_CONTAINER (bin->child))
                        return gtk_container_focus (GTK_CONTAINER (bin->child), direction);
                else if (GTK_WIDGET_CAN_FOCUS (bin->child)) {
                        gtk_widget_grab_focus (bin->child);
                        return TRUE;
                } else
                        return FALSE;
        } else
                return FALSE;
}

/* Set_focus handler for the plug widget */
static void
bonobo_plug_set_focus (GtkWindow *window, GtkWidget *focus)
{
        BonoboPlug *plug;
        BonoboPlugPrivate *priv;

        plug = BONOBO_PLUG (window);
        priv = plug->priv;

        (* GTK_WINDOW_CLASS (parent_class)->set_focus) (window, focus);

        if (focus && GTK_WIDGET_CAN_FOCUS (focus) && !GTK_WIDGET_HAS_FOCUS (window)) {
                XEvent xevent;

                xevent.xfocus.type = FocusIn;
                xevent.xfocus.display = GDK_WINDOW_XDISPLAY (GTK_WIDGET (plug)->window);
                xevent.xfocus.window = GDK_WINDOW_XWINDOW (priv->socket_window);
                xevent.xfocus.mode = EMBEDDED_APP_WANTS_FOCUS;
                xevent.xfocus.detail = FALSE; /* Don't force */

                gdk_error_trap_push ();
                XSendEvent (gdk_display,
                            GDK_WINDOW_XWINDOW (priv->socket_window),
                            False, NoEventMask, &xevent);
                gdk_flush ();
                gdk_error_trap_pop ();
        }
}

static void
bonobo_plug_init (BonoboPlug *plug)
{
        BonoboPlugPrivate *priv;
        GtkWindow *window;

        priv = g_new0 (BonoboPlugPrivate, 1);
        plug->priv = priv;

        window = GTK_WINDOW (plug);

        window->type = GTK_WINDOW_TOPLEVEL;
        window->auto_shrink = TRUE;

        priv->control = NULL;
        priv->has_focus = FALSE;
}

/* Sets up the key event filter and key event table; see the comments for
 * key_event_table above.
 */
static void
setup_event_filter (void)
{
        key_event_table_head = key_event_table_tail = key_event_table_nelements = 0;

        /* This is a default event filter, so we pass NULL for the window field */
        gdk_window_add_filter (NULL, event_filter_cb, NULL);
}

static void
bonobo_plug_class_init (BonoboPlugClass *class)
{
        GtkObjectClass *object_class;
        GtkWidgetClass *widget_class;
        GtkContainerClass *container_class;
        GtkWindowClass *window_class;

        object_class = (GtkObjectClass *) class;
        widget_class = (GtkWidgetClass *) class;
        container_class = (GtkContainerClass *) class;
        window_class = (GtkWindowClass *) class;

        parent_class = gtk_type_class (gtk_window_get_type ());

        object_class->destroy = bonobo_plug_destroy;

        widget_class->map = bonobo_plug_map;
        widget_class->realize = bonobo_plug_realize;
        widget_class->unrealize = bonobo_plug_unrealize;
        widget_class->key_press_event = bonobo_plug_key_press_event;
        widget_class->key_release_event = bonobo_plug_key_release_event;
        widget_class->focus_in_event = bonobo_plug_focus_in_event;
        widget_class->focus_out_event = bonobo_plug_focus_out_event;

        container_class->focus = bonobo_plug_focus;

        window_class->set_focus = bonobo_plug_set_focus;

        setup_event_filter ();
}

guint
bonobo_plug_get_type ()
{
        static guint plug_type = 0;

        if (!plug_type)
        {
                static const GtkTypeInfo plug_info =
                {
                        "BonoboPlug",
                        sizeof (BonoboPlug),
                        sizeof (BonoboPlugClass),
                        (GtkClassInitFunc) bonobo_plug_class_init,
                        (GtkObjectInitFunc) bonobo_plug_init,
                        (GtkArgSetFunc) NULL,
                        (GtkArgGetFunc) NULL
                };

                plug_type = gtk_type_unique (gtk_window_get_type (), &plug_info);
        }

        return plug_type;
}

/**
 * bonobo_plug_set_control:
 * @plug: A plug.
 * @control: Control that wraps the plug widget.
 *
 * Sets the #BonoboControl that the plug will use to proxy requests to the
 * parent container.
 **/
void
bonobo_plug_set_control (BonoboPlug *plug, BonoboControl *control)
{
        BonoboPlugPrivate *priv;

        g_return_if_fail (plug != NULL);
        g_return_if_fail (BONOBO_IS_PLUG (plug));

        priv = plug->priv;
        g_return_if_fail (priv->control == NULL);

        g_return_if_fail (control != NULL);
        g_return_if_fail (BONOBO_IS_CONTROL (control));

        priv->control = control;
}

/**
 * bonobo_plug_clear_focus_chain:
 * @plug: A plug.
 *
 * Clears the focus children from the container hierarchy inside a plug.  This
 * should be used only by the #BonoboControl implementation.
 **/
void
bonobo_plug_clear_focus_chain (BonoboPlug *plug)
{
        BonoboPlugPrivate *priv;

        g_return_if_fail (plug != NULL);
        g_return_if_fail (BONOBO_IS_PLUG (plug));

        priv = plug->priv;

        if (GTK_WINDOW (plug)->focus_widget) {
                GtkWidget *parent;

                parent = GTK_WINDOW (plug)->focus_widget->parent;
                while (parent) {
                        gtk_container_set_focus_child (GTK_CONTAINER (parent), NULL);
                        parent = parent->parent;
                }

                gtk_window_set_focus (GTK_WINDOW (plug), NULL);
        }
}