libsystemd-bus: add lightweight object vtable implementation for exposing objects on the bus

This adds a lightweight scheme how to define interfaces in static fixed
arrays which then can be easily registered on a bus connection. This
makes it much easier to write bus services.

This automatically handles implementation of the Properties,
ObjectManager, and Introspection bus interfaces.

1 files changed, 63 insertions, 0 deletions

diff --git a/src/libsystemd-bus/test-bus-introspect.c b/src/libsystemd-bus/test-bus-introspect.c
new file mode 100644
index 0000000000..ea26cdd101
--- /dev/null
+++ b/src/libsystemd-bus/test-bus-introspect.c
@@ -0,0 +1,63 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "util.h"
+#include "log.h"
+#include "bus-introspect.h"
+
+static int prop_get(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *reply, sd_bus_error *error, void *userdata) {
+        return -EINVAL;
+}
+
+static int prop_set(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *reply, sd_bus_error *error, void *userdata) {
+        return -EINVAL;
+}
+
+static const sd_bus_vtable vtable[] = {
+        SD_BUS_VTABLE_START(0),
+        SD_BUS_METHOD("Hello", "ssas", "a(uu)", 0, NULL),
+        SD_BUS_METHOD("DeprecatedHello", "", "", SD_BUS_VTABLE_DEPRECATED, NULL),
+        SD_BUS_METHOD("DeprecatedHelloNoReply", "", "", SD_BUS_VTABLE_DEPRECATED|SD_BUS_VTABLE_METHOD_NO_REPLY, NULL),
+        SD_BUS_SIGNAL("Wowza", "sss", 0),
+        SD_BUS_SIGNAL("DeprecatedWowza", "ut", SD_BUS_VTABLE_DEPRECATED),
+        SD_BUS_WRITABLE_PROPERTY("AProperty", "s", prop_get, prop_set, 0, 0),
+        SD_BUS_PROPERTY("AReadOnlyDeprecatedProperty", "(ut)", prop_get, 0, SD_BUS_VTABLE_DEPRECATED),
+        SD_BUS_PROPERTY("ChangingProperty", "t", prop_get, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
+        SD_BUS_PROPERTY("Invalidating", "t", prop_get, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE|SD_BUS_VTABLE_PROPERTY_INVALIDATE_ONLY),
+        SD_BUS_VTABLE_END
+};
+
+int main(int argc, char *argv[]) {
+        struct introspect intro;
+
+        log_set_max_level(LOG_DEBUG);
+
+        assert_se(introspect_begin(&intro) >= 0);
+
+        assert_se(introspect_write_interface(&intro, "org.foo", vtable) >= 0);
+
+        fflush(intro.f);
+        fputs(intro.introspection, stdout);
+
+        introspect_free(&intro);
+
+        return 0;
+}