sd-bus: introduce new SD_BUS_VTABLE_PROPERTY_EXPLICIT flag

This allows marking properties as "explicit". Properties marked like
this are included in the introspection, but are avoided in GetAll()
property queries, PropertiesChanged() signals and in in GetManaged()
object manager calls and InterfacesAdded() signals.

Expensive properties may be marked that way, and they will be
retrievable when explicitly being requested, but never in "blanket"
all-property queries and signals.

This flag may be combined with the flags for "const" and
"emit-validation" properties, but not with "emit-validation", as that
is only useful for properties whose value shall be sent in "blanket"
all-property signals.

The "explicit" flag is also exposed in the introspection data via a new
annotation.

diff --git a/src/libsystemd/sd-bus/bus-introspect.c b/src/libsystemd/sd-bus/bus-introspect.c
index c2233d0cf33ca62a60bd47fd63239c53b0acae95..3107d0009275848d666b154a4c213c8de631f6e3 100644 (file)
--- a/src/libsystemd/sd-bus/bus-introspect.c
+++ b/src/libsystemd/sd-bus/bus-introspect.c
@@ -81,6 +81,9 @@ static void introspect_write_flags(struct introspect *i, int type, int flags) {
                 fputs("   <annotation name=\"org.freedesktop.DBus.Method.NoReply\" value=\"true\"/>\n", i->f);
 
         if (type == _SD_BUS_VTABLE_PROPERTY || type == _SD_BUS_VTABLE_WRITABLE_PROPERTY) {
+                if (flags & SD_BUS_VTABLE_PROPERTY_EXPLICIT)
+                        fputs("   <annotation name=\"org.freedesktop.systemd1.Explicit\" value=\"true\"/>\n", i->f);
+
                 if (flags & SD_BUS_VTABLE_PROPERTY_CONST)
                         fputs("   <annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"const\"/>\n", i->f);
                 else if (flags & SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION)

diff --git a/src/libsystemd/sd-bus/bus-objects.c b/src/libsystemd/sd-bus/bus-objects.c
index b2e617ada412fde3ea501a75eb03c021b2b3a593..a8e9a12494667273cb76254e3acf8f1830911548 100644 (file)
--- a/src/libsystemd/sd-bus/bus-objects.c
+++ b/src/libsystemd/sd-bus/bus-objects.c
@@ -749,6 +749,9 @@ static int vtable_append_all_properties(
                 if (v->flags & SD_BUS_VTABLE_HIDDEN)
                         continue;
 
+                if (v->flags & SD_BUS_VTABLE_PROPERTY_EXPLICIT)
+                        continue;
+
                 r = vtable_append_one_property(bus, reply, path, c, v, userdata, error);
                 if (r < 0)
                         return r;
@@ -1740,8 +1743,9 @@ static int add_object_vtable_internal(
                         if (!member_name_is_valid(v->x.property.member) ||
                             !signature_is_single(v->x.property.signature, false) ||
                             !(v->x.property.get || bus_type_is_basic(v->x.property.signature[0]) || streq(v->x.property.signature, "as")) ||
-                            v->flags & SD_BUS_VTABLE_METHOD_NO_REPLY ||
+                            (v->flags & SD_BUS_VTABLE_METHOD_NO_REPLY) ||
                             (!!(v->flags & SD_BUS_VTABLE_PROPERTY_CONST) + !!(v->flags & SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE) + !!(v->flags & SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION)) > 1 ||
+                            ((v->flags & SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE) && (v->flags & SD_BUS_VTABLE_PROPERTY_EXPLICIT)) ||
                             (v->flags & SD_BUS_VTABLE_UNPRIVILEGED && v->type == _SD_BUS_VTABLE_PROPERTY)) {
                                 r = -EINVAL;
                                 goto fail;

diff --git a/src/libsystemd/sd-bus/test-bus-introspect.c b/src/libsystemd/sd-bus/test-bus-introspect.c
index b2caa028703ad7780cd8cbf3e3728f823898b07a..f39dedeb24a565f0f09671cc8564f087a147edac 100644 (file)
--- a/src/libsystemd/sd-bus/test-bus-introspect.c
+++ b/src/libsystemd/sd-bus/test-bus-introspect.c
@@ -41,7 +41,7 @@ static const sd_bus_vtable vtable[] = {
         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_INVALIDATION),
-        SD_BUS_PROPERTY("Constant", "t", prop_get, 0, SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("Constant", "t", prop_get, 0, SD_BUS_VTABLE_PROPERTY_CONST|SD_BUS_VTABLE_PROPERTY_EXPLICIT),
         SD_BUS_VTABLE_END
 };
 

diff --git a/src/libsystemd/sd-bus/test-bus-objects.c b/src/libsystemd/sd-bus/test-bus-objects.c
index 6b3bfad5b68c0326130fc689504eeb1ef0e01a7e..195013f49af6320141533e6a021087c87d563c0c 100644 (file)
--- a/src/libsystemd/sd-bus/test-bus-objects.c
+++ b/src/libsystemd/sd-bus/test-bus-objects.c
@@ -217,6 +217,7 @@ static const sd_bus_vtable vtable2[] = {
         SD_BUS_PROPERTY("Value2", "s", value_handler, 10, SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
         SD_BUS_PROPERTY("Value3", "s", value_handler, 10, SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("Value4", "s", value_handler, 10, 0),
+        SD_BUS_PROPERTY("AnExplicitProperty", "s", NULL, offsetof(struct context, something), SD_BUS_VTABLE_PROPERTY_EXPLICIT|SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
         SD_BUS_VTABLE_END
 };
 

diff --git a/src/systemd/sd-bus-vtable.h b/src/systemd/sd-bus-vtable.h
index bb4b1eb748aadcafbfc674d0c6c0c4c0c754688c..c5d05a2db29283ea968c85dc98be1cae3427b1ed 100644 (file)
--- a/src/systemd/sd-bus-vtable.h
+++ b/src/systemd/sd-bus-vtable.h
@@ -47,6 +47,7 @@ enum {
         SD_BUS_VTABLE_PROPERTY_CONST               = 1ULL << 4,
         SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE        = 1ULL << 5,
         SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION  = 1ULL << 6,
+        SD_BUS_VTABLE_PROPERTY_EXPLICIT            = 1ULL << 7,
         _SD_BUS_VTABLE_CAPABILITY_MASK             = 0xFFFFULL << 40
 };