new class for controlling a component, to detect when it dies.

2002-08-14  Rodrigo Moya <rodrigo@ximian.com>

	* e-component-listener.[ch]: new class for controlling a component,
	to detect when it dies.

svn path=/trunk/; revision=17786

1 files changed, 227 insertions, 0 deletions

diff --git a/e-util/e-component-listener.c b/e-util/e-component-listener.c
new file mode 100644
index 0000000000..d58f44e577
--- /dev/null
+++ b/e-util/e-component-listener.c
@@ -0,0 +1,227 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+/*
+ * Component listener.
+ *
+ * Author:
+ *   Rodrigo Moya <rodrigo@ximian.com>
+ *
+ * Copyright 2002, Ximian, Inc.
+ */
+
+#include <gtk/gtksignal.h>
+#include <bonobo/bonobo-exception.h>
+#include <bonobo/bonobo-object.h>
+#include <gal/util/e-util.h>
+#include "e-component-listener.h"
+#include <libgnome/gnome-i18n.h>
+
+#define PARENT_TYPE GTK_TYPE_OBJECT
+#define DEFAULT_PING_DELAY 10000
+
+struct _EComponentListenerPrivate {
+	Bonobo_Unknown component;
+	int ping_delay;
+	int ping_timeout_id;
+};
+
+static void e_component_listener_class_init (EComponentListenerClass *klass);
+static void e_component_listener_init       (EComponentListener *cl);
+static void e_component_listener_destroy    (GtkObject *object);
+
+static GtkObjectClass *parent_class = NULL;
+
+enum {
+	COMPONENT_DIED,
+	LAST_SIGNAL
+};
+
+static guint comp_listener_signals[LAST_SIGNAL];
+
+static void
+e_component_listener_class_init (EComponentListenerClass *klass)
+{
+	GtkObjectClass *object_class = GTK_OBJECT_CLASS (klass);
+
+	parent_class = gtk_type_class (PARENT_TYPE);
+
+	object_class->destroy = e_component_listener_destroy;
+	klass->component_died = NULL;
+
+	comp_listener_signals[COMPONENT_DIED] =
+		gtk_signal_new ("component_died",
+				GTK_RUN_FIRST,
+				object_class->type,
+				GTK_SIGNAL_OFFSET (EComponentListenerClass, component_died),
+				gtk_marshal_NONE__NONE,
+				GTK_TYPE_NONE, 0);
+	gtk_object_class_add_signals (object_class, comp_listener_signals, LAST_SIGNAL);
+}
+
+static void
+e_component_listener_init (EComponentListener *cl)
+{
+	/* allocate internal structure */
+	cl->priv = g_new (EComponentListenerPrivate, 1);
+	cl->priv->component = CORBA_OBJECT_NIL;
+	cl->priv->ping_delay = DEFAULT_PING_DELAY;
+	cl->priv->ping_timeout_id = -1;
+}
+
+static void
+e_component_listener_destroy (GtkObject *object)
+{
+	EComponentListener *cl = (EComponentListener *) object;
+
+	g_return_if_fail (E_IS_COMPONENT_LISTENER (cl));
+
+	cl->priv->component = CORBA_OBJECT_NIL;
+
+	if (cl->priv->ping_timeout_id != -1) {
+		g_source_remove (cl->priv->ping_timeout_id);
+		cl->priv->ping_timeout_id = -1;
+	}
+
+	/* free memory */
+	g_free (cl->priv);
+	cl->priv = NULL;
+
+	if (GTK_OBJECT_CLASS (parent_class)->destroy)
+		(* GTK_OBJECT_CLASS (parent_class)->destroy) (object);
+}
+
+GtkType
+e_component_listener_get_type (void)
+{
+	static GtkType type = 0;
+
+	if (!type) {
+		static const GtkTypeInfo info = {
+			"EComponentListener",
+			sizeof (EComponentListener),
+			sizeof (EComponentListenerClass),
+			(GtkClassInitFunc) e_component_listener_class_init,
+			(GtkObjectInitFunc) e_component_listener_init,
+			NULL, /* reserved_1 */
+			NULL, /* reserved_2 */
+			(GtkClassInitFunc) NULL
+		};
+
+		type = gtk_type_unique (PARENT_TYPE, &info);
+	}
+
+	return type;
+}
+
+static gboolean
+ping_component_callback (gpointer user_data)
+{
+	gboolean alive;
+	int is_nil;
+	CORBA_Environment ev;
+	EComponentListener *cl = (EComponentListener *) user_data;
+
+	g_return_val_if_fail (E_IS_COMPONENT_LISTENER (cl), FALSE);
+
+	if (cl->priv->component == CORBA_OBJECT_NIL)
+		return FALSE;
+
+	CORBA_exception_init (&ev);
+	is_nil = CORBA_Object_is_nil (cl->priv->component, &ev);
+	if (BONOBO_EX (&ev)) {
+		g_message (_("ping_timeout_callback: could not determine if the "
+			     "CORBA object is nil or not"));
+		goto out;
+	}
+	CORBA_exception_free (&ev);
+
+	if (is_nil)
+		goto out;
+
+	alive = bonobo_unknown_ping (cl->priv->component);
+	if (alive)
+		return TRUE;
+
+ out:
+	/* the component has died, so we notify and close the timeout */
+	gtk_signal_emit (GTK_OBJECT (cl), comp_listener_signals[COMPONENT_DIED]);
+
+	cl->priv->component = CORBA_OBJECT_NIL;
+	cl->priv->ping_timeout_id = -1;
+
+	return FALSE;
+}
+
+static void
+setup_ping_timeout (EComponentListener *cl)
+{
+	if (cl->priv->ping_timeout_id != -1)
+		g_source_remove (cl->priv->ping_timeout_id);
+
+	cl->priv->ping_timeout_id = g_timeout_add (cl->priv->ping_delay,
+						   ping_component_callback,
+						   cl);
+}
+
+/**
+ * e_component_listener_new
+ * @comp: Component to listen for.
+ * @ping_delay: Delay (in ms) for pinging the component.
+ *
+ * Create a new #EComponentListener object, which allows to listen
+ * for a given component and get notified when that component dies.
+ *
+ * Returns: a component listener object.
+ */
+EComponentListener *
+e_component_listener_new (Bonobo_Unknown comp, int ping_delay)
+{
+	EComponentListener *cl;
+
+	cl = gtk_type_new (E_COMPONENT_LISTENER_TYPE);
+	cl->priv->component = comp;
+
+	/* set up the timeout function */
+	cl->priv->ping_delay = ping_delay > 0 ? ping_delay : DEFAULT_PING_DELAY;
+	setup_ping_timeout (cl);
+
+	return cl;
+}
+
+/**
+ * e_component_listener_get_ping_delay
+ * @cl: A #EComponentListener object.
+ *
+ * Get the ping delay being used to listen for an object.
+ */
+int
+e_component_listener_get_ping_delay (EComponentListener *cl)
+{
+	g_return_val_if_fail (E_IS_COMPONENT_LISTENER (cl), -1);
+	return cl->priv->ping_delay;
+}
+
+void
+e_component_listener_set_ping_delay (EComponentListener *cl, int ping_delay)
+{
+	g_return_if_fail (E_IS_COMPONENT_LISTENER (cl));
+	g_return_if_fail (ping_delay > 0);
+
+	cl->priv->ping_delay = ping_delay;
+	setup_ping_timeout (cl);
+}
+
+Bonobo_Unknown
+e_component_listener_get_component (EComponentListener *cl)
+{
+	g_return_val_if_fail (E_IS_COMPONENT_LISTENER (cl), CORBA_OBJECT_NIL);
+	return cl->priv->component;
+}
+
+void
+e_component_listener_set_component (EComponentListener *cl, Bonobo_Unknown comp)
+{
+	g_return_if_fail (E_IS_COMPONENT_LISTENER (cl));
+
+	cl->priv->component = comp;
+	setup_ping_timeout (cl);
+}