st: Use g_object_notify_by_pspec() where possible

It's slightly more efficient not having to do property lookups. While
that is unlikely to be a concern for the properties in question, it's
still good practice and makes the code base a bit more consistent.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2168>

src/st/st-box-layout.c

@@ -60,8 +60,12 @@ enum {
 
   PROP_VERTICAL,
   PROP_PACK_START,
+
+  N_PROPS
 };
 
+static GParamSpec *props[N_PROPS] = { NULL, };
+
 struct _StBoxLayoutPrivate
 {
   StAdjustment *hadjustment;
@@ -169,7 +173,6 @@ st_box_layout_class_init (StBoxLayoutClass *klass)
 {
   GObjectClass *object_class = G_OBJECT_CLASS (klass);
   StWidgetClass *widget_class = ST_WIDGET_CLASS (klass);
-  GParamSpec *pspec;
 
   object_class->get_property = st_box_layout_get_property;
   object_class->set_property = st_box_layout_set_property;
@@ -182,13 +185,13 @@ st_box_layout_class_init (StBoxLayoutClass *klass)
    * A convenience property for the #ClutterBoxLayout:vertical property of the
    * internal layout for #StBoxLayout.
    */
-  pspec = g_param_spec_boolean ("vertical",
+  props[PROP_VERTICAL] =
-                                "Vertical",
+    g_param_spec_boolean ("vertical",
-                                "Whether the layout should be vertical, rather"
+                          "Vertical",
-                                "than horizontal",
+                          "Whether the layout should be vertical, rather"
-                                FALSE,
+                          "than horizontal",
-                                ST_PARAM_READWRITE);
+                          FALSE,
-  g_object_class_install_property (object_class, PROP_VERTICAL, pspec);
+                          ST_PARAM_READWRITE);
 
   /**
    * StBoxLayout:pack-start:
@@ -196,12 +199,14 @@ st_box_layout_class_init (StBoxLayoutClass *klass)
    * A convenience property for the #ClutterBoxLayout:pack-start property of the
    * internal layout for #StBoxLayout.
    */
-  pspec = g_param_spec_boolean ("pack-start",
+  props[PROP_PACK_START] =
-                                "Pack Start",
+    g_param_spec_boolean ("pack-start",
-                                "Whether to pack items at the start of the box",
+                          "Pack Start",
-                                FALSE,
+                          "Whether to pack items at the start of the box",
-                                ST_PARAM_READWRITE | G_PARAM_DEPRECATED);
+                          FALSE,
-  g_object_class_install_property (object_class, PROP_PACK_START, pspec);
+                          ST_PARAM_READWRITE | G_PARAM_DEPRECATED);
+
+  g_object_class_install_properties (object_class, N_PROPS, props);
 }
 
 static void
@@ -250,7 +255,7 @@ st_box_layout_set_vertical (StBoxLayout *box,
   if (clutter_box_layout_get_orientation (CLUTTER_BOX_LAYOUT (layout)) != orientation)
     {
       clutter_box_layout_set_orientation (CLUTTER_BOX_LAYOUT (layout), orientation);
-      g_object_notify (G_OBJECT (box), "vertical");
+      g_object_notify_by_pspec (G_OBJECT (box), props[PROP_VERTICAL]);
     }
 }
 

src/st/st-theme-context.c

@@ -46,9 +46,13 @@ struct _StThemeContext {
 enum
 {
   PROP_0,
-  PROP_SCALE_FACTOR
+  PROP_SCALE_FACTOR,
+
+  N_PROPS
 };
 
+static GParamSpec *props[N_PROPS] = { NULL, };
+
 enum
 {
   CHANGED,
@@ -85,7 +89,7 @@ st_theme_context_set_scale_factor (StThemeContext *context,
     return;
 
   context->scale_factor = scale_factor;
-  g_object_notify (G_OBJECT (context), "scale-factor");
+  g_object_notify_by_pspec (G_OBJECT (context), props[PROP_SCALE_FACTOR]);
   st_theme_context_changed (context);
 }
 
@@ -133,13 +137,14 @@ st_theme_context_class_init (StThemeContextClass *klass)
    *
    * The scaling factor used for HiDPI scaling.
    */
-  g_object_class_install_property (object_class,
+  props[PROP_SCALE_FACTOR] =
-                                   PROP_SCALE_FACTOR,
+    g_param_spec_int ("scale-factor",
-                                   g_param_spec_int ("scale-factor",
+                      "Scale factor",
-                                                     "Scale factor",
+                      "Integer scale factor used for HiDPI scaling",
-                                                     "Integer scale factor used for HiDPI scaling",
+                      0, G_MAXINT, 1,
-                                                     0, G_MAXINT, 1,
+                      ST_PARAM_READWRITE);
-                                                     ST_PARAM_READWRITE));
+
+  g_object_class_install_properties (object_class, N_PROPS, props);
 
   /**
    * StThemeContext::changed:

src/st/st-viewport.c

@@ -55,11 +55,18 @@ static void st_viewport_scrollable_interface_init (StScrollableInterface *iface)
 
 enum {
   PROP_0,
+
   PROP_CLIP_TO_VIEW,
+
+  N_PROPS,
+
+  /* StScrollable */
   PROP_HADJUST,
   PROP_VADJUST
 };
 
+static GParamSpec *props[N_PROPS] = { NULL, };
+
 typedef struct
 {
   StAdjustment *hadjustment;
@@ -177,6 +184,7 @@ st_viewport_set_clip_to_view (StViewport *viewport,
     {
       priv->clip_to_view = clip_to_view;
       clutter_actor_queue_redraw (CLUTTER_ACTOR (viewport));
+      g_object_notify_by_pspec (G_OBJECT (viewport), props[PROP_CLIP_TO_VIEW]);
     }
 }
 
@@ -588,13 +596,12 @@ st_viewport_class_init (StViewportClass *klass)
   actor_class->get_paint_volume = st_viewport_get_paint_volume;
   actor_class->pick = st_viewport_pick;
 
-  g_object_class_install_property (object_class,
+  props[PROP_CLIP_TO_VIEW] =
-                                   PROP_CLIP_TO_VIEW,
+    g_param_spec_boolean ("clip-to-view",
-                                   g_param_spec_boolean ("clip-to-view",
+                          "Clip to view",
-                                                         "Clip to view",
+                          "Clip to view",
-                                                         "Clip to view",
+                          TRUE,
-                                                         TRUE,
+                          ST_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
-                                                         ST_PARAM_READWRITE));
 
   /* StScrollable properties */
   g_object_class_override_property (object_class,
@@ -604,6 +611,8 @@ st_viewport_class_init (StViewportClass *klass)
   g_object_class_override_property (object_class,
                                     PROP_VADJUST,
                                     "vadjustment");
+
+  g_object_class_install_properties (object_class, N_PROPS, props);
 }
 
 static void