utils: Don't strip modifiers when stripping encoding

We have some locales which are dupes if we do this, for example
ca_ES.UTF-8 and ca_ES.UTF-8@valencia. The latter of these should become
ca_ES@valencia in the output. That is what `locale -a` shows.

Previously `as_locale_strip_encoding ()` modified the passed-in string
in place. However, in the one place where don't `g_strdup ()` the string
before passing to this function, it is the key in a `GHashTable`. We
can't do this, and only get away with it because the hash table isn't
touched after this call. Fix the function to instead return a newly
allocated string, and drop the `g_strdup` calls from the other call
sites.

Add a small test for this function too.

ximion/appstream-generator#92

src/as-context.c

@@ -513,7 +513,7 @@ as_context_localized_ht_set (AsContext *ctx, GHashTable *lht, const gchar *value
 	if (selected_locale == NULL)
 		selected_locale = "C";
 
-	locale_noenc = as_locale_strip_encoding (g_strdup (selected_locale));
+	locale_noenc = as_locale_strip_encoding (selected_locale);
 	g_hash_table_insert (lht,
 			     g_ref_string_new_intern (locale_noenc),
 			     g_strdup (value));

src/as-utils-private.h

@@ -97,7 +97,10 @@ AS_INTERNAL_VISIBLE
 gboolean		as_copy_file (const gchar *source, const gchar *destination, GError **error);
 
 gboolean		as_is_cruft_locale (const gchar *locale);
-gchar			*as_locale_strip_encoding (gchar *locale);
+
+AS_INTERNAL_VISIBLE
+gchar			*as_locale_strip_encoding (const gchar *locale);
+
 gchar			*as_utils_locale_to_language (const gchar *locale);
 
 gchar			*as_get_current_arch (void);

src/as-utils.c

@@ -776,16 +776,22 @@ as_is_cruft_locale (const gchar *locale)
  * as_locale_strip_encoding:
  *
  * Remove the encoding from a locale string.
- * The function modifies the string directly.
+ * The function returns a newly allocated string.
  */
 gchar*
-as_locale_strip_encoding (gchar *locale)
+as_locale_strip_encoding (const gchar *locale)
 {
-	gchar *tmp;
-	tmp = g_strstr_len (locale, -1, ".UTF-8");
-	if (tmp != NULL)
-		*tmp = '\0';
-	return locale;
+	static const char tail[] = ".UTF-8";
+	gchar *ret;
+	g_autoptr(GString) str = NULL;
+
+	str = g_string_new (locale);
+	g_string_replace (str, tail, "", 1);
+
+	ret = g_string_free (str, FALSE);
+	str = NULL;
+
+	return ret;
 }
 
 /**

src/as-yaml.c

@@ -509,7 +509,7 @@ as_yaml_set_localized_table (AsContext *ctx, GNode *node, GHashTable *l10n_table
 	for (GNode *n = node->children; n != NULL; n = n->next) {
 		const gchar *locale = as_yaml_get_node_locale (ctx, n);
 		if (locale != NULL) {
-			g_autofree gchar *locale_noenc = as_locale_strip_encoding (g_strdup (locale));
+			g_autofree gchar *locale_noenc = as_locale_strip_encoding (locale);
 			g_hash_table_insert (l10n_table,
 						g_ref_string_new_intern (locale_noenc),
 						g_strdup (as_yaml_node_get_value (n)));

tests/test-misc.c

@@ -21,6 +21,7 @@
 #include <glib.h>
 #include "appstream.h"
 #include "as-news-convert.h"
+#include "as-utils-private.h"
 
 #include "as-test-utils.h"
 
@@ -192,6 +193,22 @@ test_readwrite_text_news ()
 	g_free (tmp);
 }
 
+static void
+test_locale_strip_encoding ()
+{
+	g_autofree gchar *c = NULL;
+	g_autofree gchar *cutf8 = NULL;
+	g_autofree gchar *cutf8valencia = NULL;
+
+	c = as_locale_strip_encoding ("C");
+	cutf8 = as_locale_strip_encoding ("C.UTF-8");
+	cutf8valencia = as_locale_strip_encoding ("C.UTF-8@valencia");
+
+	g_assert_cmpstr (c, ==, "C");
+	g_assert_cmpstr (cutf8, ==, "C");
+	g_assert_cmpstr (cutf8valencia, ==, "C@valencia");
+}
+
 int
 main (int argc, char **argv)
 {
@@ -214,6 +231,7 @@ main (int argc, char **argv)
 
 	g_test_add_func ("/AppStream/Misc/YAMLNews", test_readwrite_yaml_news);
 	g_test_add_func ("/AppStream/Misc/TextNews", test_readwrite_text_news);
+	g_test_add_func ("/AppStream/Misc/StripLocaleEncoding", test_locale_strip_encoding);
 
 	ret = g_test_run ();
 	g_free (datadir);