dbus: more efficient implementation of properties

The way the various properties[] arrays are initialized is inefficient:
 - only the .data members change at runtime, yet the whole arrays of
   properties with all the fields are constructed on the stack one by
   one by the code.
 - there's duplication, eg. the properties of "org.freedesktop.systemd1.Unit"
   are repeated in several unit types.

Fix it by moving the information about properties into static const
sections. Instead of storing the .data directly in the property, store
a constant offset from a run-time base.
The small arrays of struct BusBoundProperties bind together the constant
information with the right runtime information (the base pointer).

On my system the code shrinks by 60 KB, data increases by 10 KB.

1 files changed, 100 insertions, 92 deletions

diff --git a/src/locale/localed.c b/src/locale/localed.c
index c6b48de5f..d46d91e03 100644
--- a/src/locale/localed.c
+++ b/src/locale/localed.c
@@ -129,8 +129,12 @@ static char *data[_PROP_MAX] = {
         NULL
 };
 
-static char *x11_layout = NULL, *x11_model = NULL, *x11_variant = NULL, *x11_options = NULL;
-static char *vc_keymap = NULL, *vc_keymap_toggle = NULL;
+typedef struct State {
+        char *x11_layout, *x11_model, *x11_variant, *x11_options;
+        char *vc_keymap, *vc_keymap_toggle;
+} State;
+
+static State state;
 
 static usec_t remain_until = 0;
 
@@ -160,19 +164,19 @@ static void free_data_locale(void) {
 }
 
 static void free_data_x11(void) {
-        free(x11_layout);
-        free(x11_model);
-        free(x11_variant);
-        free(x11_options);
+        free(state.x11_layout);
+        free(state.x11_model);
+        free(state.x11_variant);
+        free(state.x11_options);
 
-        x11_layout = x11_model = x11_variant = x11_options = NULL;
+        state.x11_layout = state.x11_model = state.x11_variant = state.x11_options = NULL;
 }
 
 static void free_data_vconsole(void) {
-        free(vc_keymap);
-        free(vc_keymap_toggle);
+        free(state.vc_keymap);
+        free(state.vc_keymap_toggle);
 
-        vc_keymap = vc_keymap_toggle = NULL;
+        state.vc_keymap = state.vc_keymap_toggle = NULL;
 }
 
 static void simplify(void) {
@@ -248,8 +252,8 @@ static int read_data_vconsole(void) {
         free_data_vconsole();
 
         r = parse_env_file("/etc/vconsole.conf", NEWLINE,
-                           "KEYMAP",        &vc_keymap,
-                           "KEYMAP_TOGGLE", &vc_keymap_toggle,
+                           "KEYMAP",        &state.vc_keymap,
+                           "KEYMAP_TOGGLE", &state.vc_keymap_toggle,
                            NULL);
 
         if (r < 0 && r != -ENOENT)
@@ -306,20 +310,20 @@ static int read_data_x11(void) {
                         if (strv_length(a) == 3) {
 
                                 if (streq(a[1], "XkbLayout")) {
-                                        free(x11_layout);
-                                        x11_layout = a[2];
+                                        free(state.x11_layout);
+                                        state.x11_layout = a[2];
                                         a[2] = NULL;
                                 } else if (streq(a[1], "XkbModel")) {
-                                        free(x11_model);
-                                        x11_model = a[2];
+                                        free(state.x11_model);
+                                        state.x11_model = a[2];
                                         a[2] = NULL;
                                 } else if (streq(a[1], "XkbVariant")) {
-                                        free(x11_variant);
-                                        x11_variant = a[2];
+                                        free(state.x11_variant);
+                                        state.x11_variant = a[2];
                                         a[2] = NULL;
                                 } else if (streq(a[1], "XkbOptions")) {
-                                        free(x11_options);
-                                        x11_options = a[2];
+                                        free(state.x11_options);
+                                        state.x11_options = a[2];
                                         a[2] = NULL;
                                 }
                         }
@@ -505,12 +509,12 @@ static int write_data_vconsole(void) {
         if (r < 0 && r != -ENOENT)
                 return r;
 
-        if (isempty(vc_keymap))
+        if (isempty(state.vc_keymap))
                 l = strv_env_unset(l, "KEYMAP");
         else {
                 char *s, **u;
 
-                s = strappend("KEYMAP=", vc_keymap);
+                s = strappend("KEYMAP=", state.vc_keymap);
                 if (!s) {
                         strv_free(l);
                         return -ENOMEM;
@@ -526,12 +530,12 @@ static int write_data_vconsole(void) {
                 l = u;
         }
 
-        if (isempty(vc_keymap_toggle))
+        if (isempty(state.vc_keymap_toggle))
                 l = strv_env_unset(l, "KEYMAP_TOGGLE");
         else  {
                 char *s, **u;
 
-                s = strappend("KEYMAP_TOGGLE=", vc_keymap_toggle);
+                s = strappend("KEYMAP_TOGGLE=", state.vc_keymap_toggle);
                 if (!s) {
                         strv_free(l);
                         return -ENOMEM;
@@ -567,10 +571,10 @@ static int write_data_x11(void) {
         char *temp_path;
         int r;
 
-        if (isempty(x11_layout) &&
-            isempty(x11_model) &&
-            isempty(x11_variant) &&
-            isempty(x11_options)) {
+        if (isempty(state.x11_layout) &&
+            isempty(state.x11_model) &&
+            isempty(state.x11_variant) &&
+            isempty(state.x11_options)) {
 
 #ifdef TARGET_FEDORA
                 unlink("/etc/X11/xorg.conf.d/00-system-setup-keyboard.conf");
@@ -600,17 +604,17 @@ static int write_data_x11(void) {
               "        Identifier \"system-keyboard\"\n"
               "        MatchIsKeyboard \"on\"\n", f);
 
-        if (!isempty(x11_layout))
-                fprintf(f, "        Option \"XkbLayout\" \"%s\"\n", x11_layout);
+        if (!isempty(state.x11_layout))
+                fprintf(f, "        Option \"XkbLayout\" \"%s\"\n", state.x11_layout);
 
-        if (!isempty(x11_model))
-                fprintf(f, "        Option \"XkbModel\" \"%s\"\n", x11_model);
+        if (!isempty(state.x11_model))
+                fprintf(f, "        Option \"XkbModel\" \"%s\"\n", state.x11_model);
 
-        if (!isempty(x11_variant))
-                fprintf(f, "        Option \"XkbVariant\" \"%s\"\n", x11_variant);
+        if (!isempty(state.x11_variant))
+                fprintf(f, "        Option \"XkbVariant\" \"%s\"\n", state.x11_variant);
 
-        if (!isempty(x11_options))
-                fprintf(f, "        Option \"XkbOptions\" \"%s\"\n", x11_options);
+        if (!isempty(state.x11_options))
+                fprintf(f, "        Option \"XkbOptions\" \"%s\"\n", state.x11_options);
 
         fputs("EndSection\n", f);
         fflush(f);
@@ -742,13 +746,13 @@ static int convert_vconsole_to_x11(DBusConnection *connection) {
 
         assert(connection);
 
-        if (isempty(vc_keymap)) {
+        if (isempty(state.vc_keymap)) {
 
                 modified =
-                        !isempty(x11_layout) ||
-                        !isempty(x11_model) ||
-                        !isempty(x11_variant) ||
-                        !isempty(x11_options);
+                        !isempty(state.x11_layout) ||
+                        !isempty(state.x11_model) ||
+                        !isempty(state.x11_variant) ||
+                        !isempty(state.x11_options);
 
                 free_data_x11();
         } else {
@@ -772,20 +776,20 @@ static int convert_vconsole_to_x11(DBusConnection *connection) {
                         if (r == 0)
                                 break;
 
-                        if (!streq(vc_keymap, a[0])) {
+                        if (!streq(state.vc_keymap, a[0])) {
                                 strv_free(a);
                                 continue;
                         }
 
-                        if (!streq_ptr(x11_layout, strnulldash(a[1])) ||
-                            !streq_ptr(x11_model, strnulldash(a[2])) ||
-                            !streq_ptr(x11_variant, strnulldash(a[3])) ||
-                            !streq_ptr(x11_options, strnulldash(a[4]))) {
+                        if (!streq_ptr(state.x11_layout, strnulldash(a[1])) ||
+                            !streq_ptr(state.x11_model, strnulldash(a[2])) ||
+                            !streq_ptr(state.x11_variant, strnulldash(a[3])) ||
+                            !streq_ptr(state.x11_options, strnulldash(a[4]))) {
 
-                                if (free_and_set(&x11_layout, strnulldash(a[1])) < 0 ||
-                                    free_and_set(&x11_model, strnulldash(a[2])) < 0 ||
-                                    free_and_set(&x11_variant, strnulldash(a[3])) < 0 ||
-                                    free_and_set(&x11_options, strnulldash(a[4])) < 0) {
+                                if (free_and_set(&state.x11_layout, strnulldash(a[1])) < 0 ||
+                                    free_and_set(&state.x11_model, strnulldash(a[2])) < 0 ||
+                                    free_and_set(&state.x11_variant, strnulldash(a[3])) < 0 ||
+                                    free_and_set(&state.x11_options, strnulldash(a[4])) < 0) {
                                         strv_free(a);
                                         fclose(f);
                                         return -ENOMEM;
@@ -836,11 +840,11 @@ static int convert_x11_to_vconsole(DBusConnection *connection) {
 
         assert(connection);
 
-        if (isempty(x11_layout)) {
+        if (isempty(state.x11_layout)) {
 
                 modified =
-                        !isempty(vc_keymap) ||
-                        !isempty(vc_keymap_toggle);
+                        !isempty(state.vc_keymap) ||
+                        !isempty(state.vc_keymap_toggle);
 
                 free_data_x11();
         } else {
@@ -868,13 +872,13 @@ static int convert_x11_to_vconsole(DBusConnection *connection) {
                                 break;
 
                         /* Determine how well matching this entry is */
-                        if (streq_ptr(x11_layout, a[1]))
+                        if (streq_ptr(state.x11_layout, a[1]))
                                 /* If we got an exact match, this is best */
                                 matching = 10;
                         else {
                                 size_t x;
 
-                                x = strcspn(x11_layout, ",");
+                                x = strcspn(state.x11_layout, ",");
 
                                 /* We have multiple X layouts, look
                                  * for an entry that matches our key
@@ -882,7 +886,7 @@ static int convert_x11_to_vconsole(DBusConnection *connection) {
                                  * layout stripped off. */
                                 if (x > 0 &&
                                     strlen(a[1]) == x &&
-                                    strncmp(x11_layout, a[1], x) == 0)
+                                    strncmp(state.x11_layout, a[1], x) == 0)
                                         matching = 5;
                                 else  {
                                         size_t w;
@@ -894,19 +898,19 @@ static int convert_x11_to_vconsole(DBusConnection *connection) {
                                         w = strcspn(a[1], ",");
 
                                         if (x > 0 && x == w &&
-                                            memcmp(x11_layout, a[1], x) == 0)
+                                            memcmp(state.x11_layout, a[1], x) == 0)
                                                 matching = 1;
                                 }
                         }
 
                         if (matching > 0 &&
-                            streq_ptr(x11_model, a[2])) {
+                            streq_ptr(state.x11_model, a[2])) {
                                 matching++;
 
-                                if (streq_ptr(x11_variant, a[3])) {
+                                if (streq_ptr(state.x11_variant, a[3])) {
                                         matching++;
 
-                                        if (streq_ptr(x11_options, a[4]))
+                                        if (streq_ptr(state.x11_options, a[4]))
                                                 matching++;
                                 }
                         }
@@ -931,12 +935,12 @@ static int convert_x11_to_vconsole(DBusConnection *connection) {
 
                 fclose(f);
 
-                if (!streq_ptr(vc_keymap, new_keymap)) {
-                        free(vc_keymap);
-                        vc_keymap = new_keymap;
+                if (!streq_ptr(state.vc_keymap, new_keymap)) {
+                        free(state.vc_keymap);
+                        state.vc_keymap = new_keymap;
 
-                        free(vc_keymap_toggle);
-                        vc_keymap_toggle = NULL;
+                        free(state.vc_keymap_toggle);
+                        state.vc_keymap_toggle = NULL;
 
                         modified = true;
                 } else
@@ -1001,22 +1005,27 @@ static int append_locale(DBusMessageIter *i, const char *property, void *userdat
         return r;
 }
 
+static const BusProperty bus_locale_properties[] = {
+        { "Locale",               append_locale,             "as", 0 },
+        { "X11Layout",            bus_property_append_string, "s", offsetof(State, x11_layout),       true },
+        { "X11Model",             bus_property_append_string, "s", offsetof(State, x11_model),        true },
+        { "X11Variant",           bus_property_append_string, "s", offsetof(State, x11_variant),      true },
+        { "X11Options",           bus_property_append_string, "s", offsetof(State, x11_options),      true },
+        { "VConsoleKeymap",       bus_property_append_string, "s", offsetof(State, vc_keymap),        true },
+        { "VConsoleKeymapToggle", bus_property_append_string, "s", offsetof(State, vc_keymap_toggle), true },
+        { NULL, }
+};
+
+static const BusBoundProperties bps[] = {
+        { "org.freedesktop.locale1", bus_locale_properties, &state },
+        { NULL, }
+};
+
 static DBusHandlerResult locale_message_handler(
                 DBusConnection *connection,
                 DBusMessage *message,
                 void *userdata) {
 
-        const BusProperty properties[] = {
-                { "org.freedesktop.locale1", "Locale",               append_locale,              "as", NULL                   },
-                { "org.freedesktop.locale1", "X11Layout",            bus_property_append_string, "s",  x11_layout             },
-                { "org.freedesktop.locale1", "X11Model",             bus_property_append_string, "s",  x11_model              },
-                { "org.freedesktop.locale1", "X11Variant",           bus_property_append_string, "s",  x11_variant            },
-                { "org.freedesktop.locale1", "X11Options",           bus_property_append_string, "s",  x11_options            },
-                { "org.freedesktop.locale1", "VConsoleKeymap",       bus_property_append_string, "s",  vc_keymap              },
-                { "org.freedesktop.locale1", "VConsoleKeymapToggle", bus_property_append_string, "s",  vc_keymap_toggle       },
-                { NULL, NULL, NULL, NULL, NULL }
-        };
-
         DBusMessage *reply = NULL, *changed = NULL;
         DBusError error;
         int r;
@@ -1169,15 +1178,15 @@ static DBusHandlerResult locale_message_handler(
                 if (isempty(keymap_toggle))
                         keymap_toggle = NULL;
 
-                if (!streq_ptr(keymap, vc_keymap) ||
-                    !streq_ptr(keymap_toggle, vc_keymap_toggle)) {
+                if (!streq_ptr(keymap, state.vc_keymap) ||
+                    !streq_ptr(keymap_toggle, state.vc_keymap_toggle)) {
 
                         r = verify_polkit(connection, message, "org.freedesktop.locale1.set-keyboard", interactive, &error);
                         if (r < 0)
                                 return bus_send_error_reply(connection, message, &error, r);
 
-                        if (free_and_set(&vc_keymap, keymap) < 0 ||
-                            free_and_set(&vc_keymap_toggle, keymap_toggle) < 0)
+                        if (free_and_set(&state.vc_keymap, keymap) < 0 ||
+                            free_and_set(&state.vc_keymap_toggle, keymap_toggle) < 0)
                                 goto oom;
 
                         r = write_data_vconsole();
@@ -1186,7 +1195,7 @@ static DBusHandlerResult locale_message_handler(
                                 return bus_send_error_reply(connection, message, NULL, r);
                         }
 
-                        log_info("Changed virtual console keymap to '%s'", strempty(vc_keymap));
+                        log_info("Changed virtual console keymap to '%s'", strempty(state.vc_keymap));
 
                         r = load_vconsole_keymap(connection, NULL);
                         if (r < 0)
@@ -1237,19 +1246,19 @@ static DBusHandlerResult locale_message_handler(
                 if (isempty(options))
                         options = NULL;
 
-                if (!streq_ptr(layout, x11_layout) ||
-                    !streq_ptr(model, x11_model) ||
-                    !streq_ptr(variant, x11_variant) ||
-                    !streq_ptr(options, x11_options)) {
+                if (!streq_ptr(layout, state.x11_layout) ||
+                    !streq_ptr(model, state.x11_model) ||
+                    !streq_ptr(variant, state.x11_variant) ||
+                    !streq_ptr(options, state.x11_options)) {
 
                         r = verify_polkit(connection, message, "org.freedesktop.locale1.set-keyboard", interactive, &error);
                         if (r < 0)
                                 return bus_send_error_reply(connection, message, &error, r);
 
-                        if (free_and_set(&x11_layout, layout) < 0 ||
-                            free_and_set(&x11_model, model) < 0 ||
-                            free_and_set(&x11_variant, variant) < 0 ||
-                            free_and_set(&x11_options, options) < 0)
+                        if (free_and_set(&state.x11_layout, layout) < 0 ||
+                            free_and_set(&state.x11_model, model) < 0 ||
+                            free_and_set(&state.x11_variant, variant) < 0 ||
+                            free_and_set(&state.x11_options, options) < 0)
                                 goto oom;
 
                         r = write_data_x11();
@@ -1258,7 +1267,7 @@ static DBusHandlerResult locale_message_handler(
                                 return bus_send_error_reply(connection, message, NULL, r);
                         }
 
-                        log_info("Changed X11 keyboard layout to '%s'", strempty(x11_layout));
+                        log_info("Changed X11 keyboard layout to '%s'", strempty(state.x11_layout));
 
                         changed = bus_properties_changed_new(
                                         "/org/freedesktop/locale1",
@@ -1278,8 +1287,7 @@ static DBusHandlerResult locale_message_handler(
                         }
                 }
         } else
-                return bus_default_message_handler(connection, message, INTROSPECTION, INTERFACES_LIST, properties);
-
+                return bus_default_message_handler(connection, message, INTROSPECTION, INTERFACES_LIST, bps);
 
         if (!(reply = dbus_message_new_method_return(message)))
                 goto oom;