[gnome-software: 19/25] gs-category: Reduce string copies by pointing to static desktop data

[Philip Withnall <pwithnall src gnome org>]

commit cdf82a4333a839e4444a9b1ba38436784320d6dc
Author: Philip Withnall <pwithnall endlessos org>
Date:   Tue Feb 2 00:47:50 2021 +0000

    gs-category: Reduce string copies by pointing to static desktop data
    
    This data will last the life of the process, so point to it is safe,
    saves two pointers and three string copies per `GsCategory`.
    
    Signed-off-by: Philip Withnall <pwithnall endlessos org>

 lib/gs-category.c | 91 +++++++++++++++++++++++++++++++++----------------------
 1 file changed, 54 insertions(+), 37 deletions(-)
---
diff --git a/lib/gs-category.c b/lib/gs-category.c
index 5f1affbec..437f55a1f 100644
--- a/lib/gs-category.c
+++ b/lib/gs-category.c
@@ -27,10 +27,9 @@ struct _GsCategory
 {
        GObject          parent_instance;
 
-       gchar           *id;
-       gchar           *name;
-       gchar           *icon_name;
-       gint             score;
+       const GsDesktopData     *desktop_data;  /* NULL for subcategories */
+       const GsDesktopMap      *desktop_map;  /* NULL for parent categories */
+
        GPtrArray       *desktop_groups;
        GsCategory      *parent;
        guint            size;
@@ -67,14 +66,14 @@ gs_category_to_string (GsCategory *category)
        GString *str = g_string_new (NULL);
        g_string_append_printf (str, "GsCategory[%p]:\n", category);
        g_string_append_printf (str, "  id: %s\n",
-                               category->id);
-       if (category->name != NULL) {
+                               gs_category_get_id (category));
+       if (gs_category_get_name (category) != NULL) {
                g_string_append_printf (str, "  name: %s\n",
-                                       category->name);
+                                       gs_category_get_name (category));
        }
-       if (category->icon_name != NULL) {
+       if (gs_category_get_icon_name (category) != NULL) {
                g_string_append_printf (str, "  icon-name: %s\n",
-                                       category->icon_name);
+                                       gs_category_get_icon_name (category));
        }
        g_string_append_printf (str, "  size: %u\n",
                                gs_category_get_size (category));
@@ -84,7 +83,7 @@ gs_category_to_string (GsCategory *category)
                g_string_append_printf (str, "  parent: %s\n",
                                        gs_category_get_id (category->parent));
        }
-       g_string_append_printf (str, "  score: %i\n", category->score);
+       g_string_append_printf (str, "  score: %i\n", gs_category_get_score (category));
        if (category->children->len == 0) {
                g_string_append_printf (str, "  children: %u\n",
                                        category->children->len);
@@ -118,7 +117,7 @@ gs_category_get_size (GsCategory *category)
        g_return_val_if_fail (GS_IS_CATEGORY (category), 0);
 
        /* The ‘all’ subcategory is a bit special. */
-       if (category->parent != NULL && g_str_equal (category->id, "all"))
+       if (category->parent != NULL && g_str_equal (gs_category_get_id (category), "all"))
                return gs_category_get_size (category->parent);
 
        return category->size;
@@ -177,7 +176,12 @@ const gchar *
 gs_category_get_id (GsCategory *category)
 {
        g_return_val_if_fail (GS_IS_CATEGORY (category), NULL);
-       return category->id;
+
+       if (category->desktop_data != NULL)
+               return category->desktop_data->id;
+       else if (category->desktop_map != NULL)
+               return category->desktop_map->id;
+       g_assert_not_reached ();
 }
 
 /**
@@ -193,25 +197,37 @@ gs_category_get_id (GsCategory *category)
 const gchar *
 gs_category_get_name (GsCategory *category)
 {
+       const gchar *category_id;
+
        g_return_val_if_fail (GS_IS_CATEGORY (category), NULL);
 
+       category_id = gs_category_get_id (category);
+
        /* special case, we don't want translations in the plugins */
-       if (g_strcmp0 (category->id, "other") == 0) {
+       if (g_strcmp0 (category_id, "other") == 0) {
                /* TRANSLATORS: this is where all applications that don't
                 * fit in other groups are put */
                return _("Other");
        }
-       if (g_strcmp0 (category->id, "all") == 0) {
+       if (g_strcmp0 (category_id, "all") == 0) {
                /* TRANSLATORS: this is a subcategory matching all the
                 * different apps in the parent category, e.g. "Games" */
                return _("All");
        }
-       if (g_strcmp0 (category->id, "featured") == 0) {
+       if (g_strcmp0 (category_id, "featured") == 0) {
                /* TRANSLATORS: this is a subcategory of featured apps */
                return _("Featured");
        }
 
-       return category->name;
+       /* normal case */
+       if (category->desktop_data != NULL) {
+               return gettext (category->desktop_data->name);
+       } else if (category->desktop_map != NULL) {
+               g_autofree gchar *msgctxt = g_strdup_printf ("Menu of %s", 
category->parent->desktop_data->name);
+               return g_dpgettext2 (GETTEXT_PACKAGE, msgctxt, category->desktop_map->name);
+       }
+
+       g_assert_not_reached ();
 }
 
 /**
@@ -227,17 +243,24 @@ gs_category_get_name (GsCategory *category)
 const gchar *
 gs_category_get_icon_name (GsCategory *category)
 {
+       const gchar *category_id;
+
        g_return_val_if_fail (GS_IS_CATEGORY (category), NULL);
 
+       category_id = gs_category_get_id (category);
+
        /* special case */
-       if (g_strcmp0 (category->id, "other") == 0)
+       if (g_strcmp0 (category_id, "other") == 0)
                return "emblem-system-symbolic";
-       if (g_strcmp0 (category->id, "all") == 0)
+       if (g_strcmp0 (category_id, "all") == 0)
                return "emblem-default-symbolic";
-       if (g_strcmp0 (category->id, "featured") == 0)
+       if (g_strcmp0 (category_id, "featured") == 0)
                return "emblem-favorite-symbolic";
 
-       return category->icon_name;
+       if (category->desktop_data != NULL)
+               return category->desktop_data->icon;
+       else
+               return NULL;
 }
 
 /**
@@ -256,7 +279,11 @@ gint
 gs_category_get_score (GsCategory *category)
 {
        g_return_val_if_fail (GS_IS_CATEGORY (category), FALSE);
-       return category->score;
+
+       if (category->desktop_data != NULL)
+               return category->desktop_data->score;
+       else
+               return 0;
 }
 
 /**
@@ -456,16 +483,16 @@ gs_category_get_property (GObject *object, guint prop_id, GValue *value, GParamS
 
        switch ((GsCategoryProperty) prop_id) {
        case PROP_ID:
-               g_value_set_string (value, self->id);
+               g_value_set_string (value, gs_category_get_id (self));
                break;
        case PROP_NAME:
-               g_value_set_string (value, self->name);
+               g_value_set_string (value, gs_category_get_name (self));
                break;
        case PROP_ICON_NAME:
-               g_value_set_string (value, self->icon_name);
+               g_value_set_string (value, gs_category_get_icon_name (self));
                break;
        case PROP_SCORE:
-               g_value_set_int (value, self->score);
+               g_value_set_int (value, gs_category_get_score (self));
                break;
        case PROP_PARENT:
                g_value_set_object (value, self->parent);
@@ -512,9 +539,6 @@ gs_category_finalize (GObject *object)
                                              (gpointer *) &category->parent);
        g_ptr_array_unref (category->children);
        g_ptr_array_unref (category->desktop_groups);
-       g_free (category->id);
-       g_free (category->name);
-       g_free (category->icon_name);
 
        G_OBJECT_CLASS (gs_category_parent_class)->finalize (object);
 }
@@ -631,27 +655,20 @@ gs_category_init (GsCategory *category)
 GsCategory *
 gs_category_new_for_desktop_data (const GsDesktopData *data)
 {
-       g_autofree gchar *msgctxt = NULL;
        g_autoptr(GsCategory) category = NULL;
        GsCategory *subcategory_all = NULL;
 
        /* parent category */
        category = g_object_new (GS_TYPE_CATEGORY, NULL);
-
-       category->icon_name = g_strdup (data->icon);
-       category->name = g_strdup (gettext (data->name));
-       category->score = data->score;
+       category->desktop_data = data;
 
        /* add subcategories */
-       msgctxt = g_strdup_printf ("Menu of %s", data->name);
-
        for (gsize j = 0; data->mapping[j].id != NULL; j++) {
                const GsDesktopMap *map = &data->mapping[j];
                g_autoptr(GsCategory) sub = g_object_new (GS_TYPE_CATEGORY, NULL);
-               sub->id = g_strdup (map->id);
+               sub->desktop_map = map;
                for (gsize k = 0; map->fdo_cats[k] != NULL; k++)
                        gs_category_add_desktop_group (sub, map->fdo_cats[k]);
-               sub->name = g_strdup (g_dpgettext2 (GETTEXT_PACKAGE, msgctxt, map->name));
                gs_category_add_child (category, sub);
 
                if (g_str_equal (map->id, "all"))