From d4e7373bbbc878b0d8ed1c28e21262a6d908d616 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 13 Apr 2012 21:32:17 +0200
Subject: [PATCH] dbus: automatically send out changed events for properties
 written to

---
 src/shared/dbus-common.c | 65 +++++++++++++++++++++++++++++++++++-----
 src/shared/dbus-common.h |  1 +
 2 files changed, 59 insertions(+), 7 deletions(-)

diff --git a/src/shared/dbus-common.c b/src/shared/dbus-common.c
index 038fdd41..badd037d 100644
--- a/src/shared/dbus-common.c
+++ b/src/shared/dbus-common.c
@@ -403,6 +403,7 @@ get_prop:
                 DBusMessageIter sub;
                 char *sig;
                 void *data;
+                DBusMessage *changed;
 
                 if (!dbus_message_iter_init(message, &iter) ||
                     dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_STRING)
@@ -454,22 +455,34 @@ set_prop:
                         dbus_free(sig);
                         return bus_send_error_reply(c, message, NULL, -EINVAL);
                 }
-
                 dbus_free(sig);
 
-                data = (char*)bp->base + p->offset;
+                data = (uint8_t*) bp->base + p->offset;
                 if (p->indirect)
                         data = *(void**)data;
+
                 r = p->set(&sub, property, data);
-                if (r < 0) {
-                        if (r == -ENOMEM)
-                                goto oom;
+                if (r == -ENOMEM)
+                        goto oom;
+                else if (r < 0)
                         return bus_send_error_reply(c, message, NULL, r);
-                }
 
                 reply = dbus_message_new_method_return(message);
                 if (!reply)
                         goto oom;
+
+                /* Send out a signal about this, but it doesn't really
+                 * matter if this fails, so eat all errors */
+                changed = bus_properties_changed_one_new(
+                                dbus_message_get_path(message),
+                                interface,
+                                property);
+                if (changed) {
+                        dbus_connection_send(c, changed, NULL);
+                        dbus_message_unref(changed);
+                }
+
+
         } else {
                 const char *interface = dbus_message_get_interface(message);
 
@@ -729,7 +742,8 @@ DBusMessage* bus_properties_changed_new(const char *path, const char *interface,
         assert(interface);
         assert(properties);
 
-        if (!(m = dbus_message_new_signal(path, "org.freedesktop.DBus.Properties", "PropertiesChanged")))
+        m = dbus_message_new_signal(path, "org.freedesktop.DBus.Properties", "PropertiesChanged");
+        if (!m)
                 goto oom;
 
         dbus_message_iter_init_append(m, &iter);
@@ -759,6 +773,43 @@ oom:
         return NULL;
 }
 
+DBusMessage* bus_properties_changed_one_new(const char *path, const char *interface, const char *property) {
+        DBusMessage *m;
+        DBusMessageIter iter, sub;
+
+        assert(interface);
+        assert(property);
+
+        m = dbus_message_new_signal(path, "org.freedesktop.DBus.Properties", "PropertiesChanged");
+        if (!m)
+                goto oom;
+
+        dbus_message_iter_init_append(m, &iter);
+
+        /* We won't send any property values, since they might be
+         * large and sometimes not cheap to generated */
+
+        if (!dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING, &interface) ||
+            !dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY, "{sv}", &sub) ||
+            !dbus_message_iter_close_container(&iter, &sub) ||
+            !dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY, "s", &sub))
+                goto oom;
+
+        if (!dbus_message_iter_append_basic(&sub, DBUS_TYPE_STRING, &property))
+                goto oom;
+
+        if (!dbus_message_iter_close_container(&iter, &sub))
+                goto oom;
+
+        return m;
+
+oom:
+        if (m)
+                dbus_message_unref(m);
+
+        return NULL;
+}
+
 uint32_t bus_flags_to_events(DBusWatch *bus_watch) {
         unsigned flags;
         uint32_t events = 0;
diff --git a/src/shared/dbus-common.h b/src/shared/dbus-common.h
index 38d8e653..ca398fc3 100644
--- a/src/shared/dbus-common.h
+++ b/src/shared/dbus-common.h
@@ -178,6 +178,7 @@ int bus_property_append_long(DBusMessageIter *i, const char *property, void *dat
 const char *bus_errno_to_dbus(int error);
 
 DBusMessage* bus_properties_changed_new(const char *path, const char *interface, const char *properties);
+DBusMessage* bus_properties_changed_one_new(const char *path, const char *interface, const char *property);
 
 uint32_t bus_flags_to_events(DBusWatch *bus_watch);
 unsigned bus_events_to_flags(uint32_t events);
-- 
2.39.5