as-content-rating: Make default values match OARS semantics

If an OARS key is missing from a `<content_rating/>` element, the
default value should be `none`, not `unknown`. Change the implementation
of `as_content_rating_get_value()` to do that, and add some tests.

See the OARS specification:
https://github.com/hughsie/oars/blob/master/specification/oars-1.1.md

Signed-off-by: Philip Withnall <withnall@endlessm.com>

2 files changed, 106 insertions, 30 deletions

diff --git a/libappstream-glib/as-content-rating.c b/libappstream-glib/as-content-rating.c
index 6d6ae76..11bc20d 100644
--- a/libappstream-glib/as-content-rating.c
+++ b/libappstream-glib/as-content-rating.c
@@ -38,6 +38,14 @@ G_DEFINE_TYPE_WITH_PRIVATE (AsContentRating, as_content_rating, G_TYPE_OBJECT)
 
 #define GET_PRIVATE(o) (as_content_rating_get_instance_private (o))
 
+typedef enum
+{
+	OARS_1_0,
+	OARS_1_1,
+} OarsVersion;
+
+static gboolean is_oars_key (const gchar *id, OarsVersion version);
+
 static void
 as_content_rating_finalize (GObject *object)
 {
@@ -139,7 +147,18 @@ as_content_rating_get_value (AsContentRating *content_rating, const gchar *id)
 		if (g_strcmp0 (key->id, id) == 0)
 			return key->value;
 	}
-	return AS_CONTENT_RATING_VALUE_UNKNOWN;
+
+	/* According to the
+	 * [OARS specification](https://github.com/hughsie/oars/blob/master/specification/oars-1.1.md),
+	 * return %AS_CONTENT_RATING_VALUE_NONE if the #AsContentRating exists
+	 * overall. Only return %AS_CONTENT_RATING_VALUE_UNKNOWN if the
+	 * #AsContentRating doesn’t exist at all (or for other types of content
+	 * rating). */
+	if ((g_strcmp0 (priv->kind, "oars-1.0") == 0 && is_oars_key (id, OARS_1_0)) ||
+	    (g_strcmp0 (priv->kind, "oars-1.1") == 0 && is_oars_key (id, OARS_1_1)))
+		return AS_CONTENT_RATING_VALUE_NONE;
+	else
+		return AS_CONTENT_RATING_VALUE_UNKNOWN;
 }
 
 /**
@@ -196,6 +215,7 @@ G_STATIC_ASSERT (AS_CONTENT_RATING_VALUE_LAST == AS_CONTENT_RATING_VALUE_INTENSE
 
 static const struct {
 	const gchar	*id;
+	OarsVersion	 oars_version;  /* when the key was first added */
 	guint		 csm_age_none;  /* for %AS_CONTENT_RATING_VALUE_NONE */
 	guint		 csm_age_mild;  /* for %AS_CONTENT_RATING_VALUE_MILD */
 	guint		 csm_age_moderate;  /* for %AS_CONTENT_RATING_VALUE_MODERATE */
@@ -204,37 +224,47 @@ static const struct {
 	/* Each @id must only appear once. The set of @csm_age_* values for a
 	 * given @id must be complete and non-decreasing. */
 	/* v1.0 */
-	{ "violence-cartoon",	0, 3, 4, 6 },
-	{ "violence-fantasy",	0, 3, 7, 8 },
-	{ "violence-realistic",	0, 4, 9, 14 },
-	{ "violence-bloodshed",	0, 9, 11, 18 },
-	{ "violence-sexual",	0, 18, 18, 18 },
-	{ "drugs-alcohol",	0, 11, 13, 16 },
-	{ "drugs-narcotics",	0, 12, 14, 17 },
-	{ "drugs-tobacco",	0, 10, 13, 13 },
-	{ "sex-nudity",		0, 12, 14, 14 },
-	{ "sex-themes",		0, 13, 14, 15 },
-	{ "language-profanity",	0, 8, 11, 14 },
-	{ "language-humor",	0, 3, 8, 14 },
-	{ "language-discrimination", 0, 9, 10, 11 },
-	{ "money-advertising",	0, 7, 8, 10 },
-	{ "money-gambling",	0, 7, 10, 18 },
-	{ "money-purchasing",	0, 12, 14, 15 },
-	{ "social-chat",	0, 4, 10, 13 },
-	{ "social-audio",	0, 15, 15, 15 },
-	{ "social-contacts",	0, 12, 12, 12 },
-	{ "social-info",	0, 0, 13, 13 },
-	{ "social-location",	0, 13, 13, 13 },
+	{ "violence-cartoon",	OARS_1_0, 0, 3, 4, 6 },
+	{ "violence-fantasy",	OARS_1_0, 0, 3, 7, 8 },
+	{ "violence-realistic",	OARS_1_0, 0, 4, 9, 14 },
+	{ "violence-bloodshed",	OARS_1_0, 0, 9, 11, 18 },
+	{ "violence-sexual",	OARS_1_0, 0, 18, 18, 18 },
+	{ "drugs-alcohol",	OARS_1_0, 0, 11, 13, 16 },
+	{ "drugs-narcotics",	OARS_1_0, 0, 12, 14, 17 },
+	{ "drugs-tobacco",	OARS_1_0, 0, 10, 13, 13 },
+	{ "sex-nudity",		OARS_1_0, 0, 12, 14, 14 },
+	{ "sex-themes",		OARS_1_0, 0, 13, 14, 15 },
+	{ "language-profanity",	OARS_1_0, 0, 8, 11, 14 },
+	{ "language-humor",	OARS_1_0, 0, 3, 8, 14 },
+	{ "language-discrimination", OARS_1_0, 0, 9, 10, 11 },
+	{ "money-advertising",	OARS_1_0, 0, 7, 8, 10 },
+	{ "money-gambling",	OARS_1_0, 0, 7, 10, 18 },
+	{ "money-purchasing",	OARS_1_0, 0, 12, 14, 15 },
+	{ "social-chat",	OARS_1_0, 0, 4, 10, 13 },
+	{ "social-audio",	OARS_1_0, 0, 15, 15, 15 },
+	{ "social-contacts",	OARS_1_0, 0, 12, 12, 12 },
+	{ "social-info",	OARS_1_0, 0, 0, 13, 13 },
+	{ "social-location",	OARS_1_0, 0, 13, 13, 13 },
 	/* v1.1 additions */
-	{ "sex-homosexuality",	0, 10, 13, 18 },
-	{ "sex-prostitution",	0, 12, 14, 18 },
-	{ "sex-adultery",	0, 8, 10, 18 },
-	{ "sex-appearance",	0, 10, 10, 15 },
-	{ "violence-worship",	0, 13, 15, 18 },
-	{ "violence-desecration", 0, 13, 15, 18 },
-	{ "violence-slavery",	0, 13, 15, 18 },
+	{ "sex-homosexuality",	OARS_1_1, 0, 10, 13, 18 },
+	{ "sex-prostitution",	OARS_1_1, 0, 12, 14, 18 },
+	{ "sex-adultery",	OARS_1_1, 0, 8, 10, 18 },
+	{ "sex-appearance",	OARS_1_1, 0, 10, 10, 15 },
+	{ "violence-worship",	OARS_1_1, 0, 13, 15, 18 },
+	{ "violence-desecration", OARS_1_1, 0, 13, 15, 18 },
+	{ "violence-slavery",	OARS_1_1, 0, 13, 15, 18 },
 };
 
+static gboolean
+is_oars_key (const gchar *id, OarsVersion version)
+{
+	for (gsize i = 0; i < G_N_ELEMENTS (oars_to_csm_mappings); i++) {
+		if (g_str_equal (id, oars_to_csm_mappings[i].id))
+			return (oars_to_csm_mappings[i].oars_version <= version);
+	}
+	return FALSE;
+}
+
 /**
  * as_content_rating_attribute_to_csm_age:
  * @id: the subsection ID e.g. `violence-cartoon`
diff --git a/libappstream-glib/as-self-test.c b/libappstream-glib/as-self-test.c
index 1de3d3d..7100f69 100644
--- a/libappstream-glib/as-self-test.c
+++ b/libappstream-glib/as-self-test.c
@@ -1743,7 +1743,7 @@ as_test_content_rating_func (void)
 	g_assert_cmpint (as_content_rating_get_value (content_rating, "violence-cartoon"), ==,
 			 AS_CONTENT_RATING_VALUE_MILD);
 	g_assert_cmpint (as_content_rating_get_value (content_rating, "violence-bloodshed"), ==,
-			 AS_CONTENT_RATING_VALUE_UNKNOWN);
+			 AS_CONTENT_RATING_VALUE_NONE);
 
 	rating_ids = as_content_rating_get_rating_ids (content_rating);
 	g_assert_nonnull (rating_ids);
@@ -1770,6 +1770,51 @@ as_test_content_rating_func (void)
 	as_node_unref (root);
 }
 
+/* Test that parsing an empty content rating correctly returns `none` as the
+ * value for all the ratings defined by that particular kind of content rating,
+ * and `unknown` for everything else. */
+static void
+as_test_content_rating_empty (void)
+{
+	GError *error = NULL;
+	AsNode *n;
+	AsNode *root;
+	const gchar *src =
+		"<content_rating type=\"oars-1.0\">\n"
+		"</content_rating>\n";
+	gboolean ret;
+	g_autoptr(AsNodeContext) ctx = NULL;
+	g_autoptr(AsContentRating) content_rating = NULL;
+
+	content_rating = as_content_rating_new ();
+
+	/* to object */
+	root = as_node_from_xml (src, 0, &error);
+	g_assert_no_error (error);
+	g_assert_nonnull (root);
+	n = as_node_find (root, "content_rating");
+	g_assert_nonnull (n);
+	ctx = as_node_context_new ();
+	ret = as_content_rating_node_parse (content_rating, n, ctx, &error);
+	g_assert_no_error (error);
+	g_assert_true (ret);
+
+	/* verify */
+	g_assert_cmpstr (as_content_rating_get_kind (content_rating), ==, "oars-1.0");
+	g_assert_cmpint (as_content_rating_get_value (content_rating, "drugs-alcohol"), ==,
+			 AS_CONTENT_RATING_VALUE_NONE);
+	g_assert_cmpint (as_content_rating_get_value (content_rating, "violence-cartoon"), ==,
+			 AS_CONTENT_RATING_VALUE_NONE);
+	g_assert_cmpint (as_content_rating_get_value (content_rating, "violence-bloodshed"), ==,
+			 AS_CONTENT_RATING_VALUE_NONE);
+
+	/* This one was only added in OARS-1.1, so it shouldn’t have a value of `none`. */
+	g_assert_cmpint (as_content_rating_get_value (content_rating, "sex-adultery"), ==,
+			 AS_CONTENT_RATING_VALUE_UNKNOWN);
+
+	as_node_unref (root);
+}
+
 /* Test that the OARS → CSM mapping table in as_content_rating_attribute_to_csm_age()
  * is complete (contains mappings for all known IDs), and that the ages it
  * returns are non-decreasing for increasing values of #AsContentRatingValue in
@@ -5625,6 +5670,7 @@ main (int argc, char **argv)
 	g_test_add_func ("/AppStream/require", as_test_require_func);
 	g_test_add_func ("/AppStream/checksum", as_test_checksum_func);
 	g_test_add_func ("/AppStream/content_rating", as_test_content_rating_func);
+	g_test_add_func ("/AppStream/content_rating/empty", as_test_content_rating_empty);
 	g_test_add_func ("/AppStream/content_rating/mappings", as_test_content_rating_mappings);
 	g_test_add_func ("/AppStream/release", as_test_release_func);
 	g_test_add_func ("/AppStream/release{date}", as_test_release_date_func);