app: Add new extra-languages key

If xa.languages is set, use these, and no others. Otherwise, take the union
of xa.extra-languages, and the system default locales for system repos;
xa.extra-languages for user repo and the langs based on the user's locale

Fixes https://github.com/flatpak/flatpak/issues/3043

app/flatpak-builtins-config.c

@@ -69,10 +69,6 @@ parse_lang (const char *value, GError **error)
   g_auto(GStrv) strs = NULL;
   int i;
 
-  if (strcmp (value, "*") == 0 ||
-      strcmp (value, "*all*") == 0)
-    return g_strdup ("");
-
   strs = g_strsplit (value, ";", 0);
   for (i = 0; strs[i]; i++)
     {
@@ -86,12 +82,28 @@ parse_lang (const char *value, GError **error)
   return g_strdup (value);
 }
 
+static char *
+parse_special_lang (const char *value, GError **error)
+{
+  if (strcmp (value, "*") == 0 ||
+      strcmp (value, "*all*") == 0)
+    return g_strdup ("");
+
+  return parse_lang (value, error);
+}
+
 static char *
 print_lang (const char *value)
+{
+  return g_strdup (value);
+}
+
+static char *
+print_special_lang (const char *value)
 {
   if (*value == 0)
     return g_strdup ("*all*");
-  return g_strdup (value);
+  return print_lang (value);
 }
 
 static char *
@@ -111,7 +123,8 @@ typedef struct
 } ConfigKey;
 
 ConfigKey keys[] = {
-  { "languages", parse_lang, print_lang, get_lang_default },
+  { "languages", parse_special_lang, print_special_lang, get_lang_default },
+  { "extra-languages", parse_lang, print_lang, NULL },
 };
 
 static ConfigKey *

common/flatpak-dir.c

@@ -14047,17 +14047,37 @@ sort_strv (char **strv)
   return strv;
 }
 
+static char **
+flatpak_dir_get_config_strv (FlatpakDir *self, char *key) 
+{
+  GKeyFile *config = flatpak_dir_get_repo_config (self);
+  g_auto(GStrv) lang = NULL;
+
+  if (config)
+    {
+      if (g_key_file_has_key (config, "core", key, NULL))
+        {
+          lang = g_key_file_get_string_list (config, "core", key, NULL, NULL);
+          return g_steal_pointer (&lang);
+        }
+    }
+  return NULL;
+}
+
 char **
 flatpak_dir_get_default_locale_languages (FlatpakDir *self)
 {
   g_autoptr(GPtrArray) langs = g_ptr_array_new_with_free_func (g_free);
   g_autoptr(GDBusProxy) localed_proxy = NULL;
   g_autoptr(GDBusProxy) accounts_proxy = NULL;
+  g_auto(GStrv) extra_languages = NULL;
+
+  extra_languages = flatpak_dir_get_config_strv (self, "xa.extra-languages");
 
   if (flatpak_dir_is_user (self))
-    return flatpak_get_current_locale_langs ();
+    return sort_strv (flatpak_strv_merge (extra_languages, flatpak_get_current_locale_langs ()));
 
-  /* First get the system default locales */
+  /* Then get the system default locales */
   localed_proxy = get_localed_dbus_proxy ();
   if (localed_proxy != NULL)
     get_locale_langs_from_localed_dbus (localed_proxy, langs);
@@ -14068,27 +14088,23 @@ flatpak_dir_get_default_locale_languages (FlatpakDir *self)
   if (accounts_proxy != NULL)
     get_locale_langs_from_accounts_dbus (accounts_proxy, langs);
 
-  /* If none were found, fall back to using all languages */
-  if (langs->len == 0)
-    return g_new0 (char *, 1);
-
-  g_ptr_array_sort (langs, flatpak_strcmp0_ptr);
   g_ptr_array_add (langs, NULL);
 
-  return (char **) g_ptr_array_free (g_steal_pointer (&langs), FALSE);
+  return sort_strv (flatpak_strv_merge (extra_languages, (char **) langs->pdata));
 }
 
 char **
 flatpak_dir_get_locale_languages (FlatpakDir *self)
 {
-  GKeyFile *config = flatpak_dir_get_repo_config (self);
+  char **langs = NULL;
 
-  if (config)
-    {
-      char **langs = g_key_file_get_string_list (config, "core", "xa.languages", NULL, NULL);
-      if (langs)
-        return sort_strv (langs);
-    }
+  /* Fetch the list of languages specified by xa.languages - if this key is empty,
+   * this would mean that all languages are accepted. You can read the man for the
+   * flatpak-config section for more info.
+   */
+  langs = flatpak_dir_get_config_strv (self, "xa.languages");
+  if (langs)
+    return sort_strv (langs);
 
   return flatpak_dir_get_default_locale_languages (self);
 }

common/flatpak-installation.c

@@ -1648,6 +1648,33 @@ flatpak_installation_get_config (FlatpakInstallation *self,
   return flatpak_dir_get_config (dir, key, error);
 }
 
+/**
+ * flatpak_installation_get_default_languages:
+ * @self: a #FlatpakInstallation
+ * @error: return location for a #GError
+ *
+ * Get the default languages used by the installation to decide which
+ * subpaths to install of locale extensions. This list may also be used
+ * by frontends like GNOME Software to decide which language-specific apps
+ * to display. An empty array means that all languages should be installed.
+ *
+ * Returns: (array zero-terminated=1) (element-type utf8) (transfer full):
+ *   A possibly empty array of locale strings, or %NULL on error.
+ * Since: 1.5.0
+ */
+char **
+flatpak_installation_get_default_languages (FlatpakInstallation  *self,
+                                            GError              **error)
+{
+  g_autoptr(FlatpakDir) dir = NULL;
+
+  dir = flatpak_installation_get_dir (self, error);
+  if (dir == NULL)
+    return NULL;
+
+  return flatpak_dir_get_locale_languages (dir);
+}
+
 /**
  * flatpak_installation_get_min_free_space_bytes:
  * @self: a #FlatpakInstallation

common/flatpak-installation.h

@@ -296,6 +296,8 @@ FLATPAK_EXTERN char *                flatpak_installation_get_config (FlatpakIns
                                                                       const char          *key,
                                                                       GCancellable        *cancellable,
                                                                       GError             **error);
+FLATPAK_EXTERN char **               flatpak_installation_get_default_languages (FlatpakInstallation  *self,
+                                                                                 GError              **error);
 FLATPAK_EXTERN char *              flatpak_installation_load_app_overrides (FlatpakInstallation *self,
                                                                             const char          *app_id,
                                                                             GCancellable        *cancellable,

doc/flatpak-config.xml

@@ -62,7 +62,15 @@
                    The languages that are included when installing Locale extensions.
                    The value is a semicolon-separated list of two-letter language codes,
                    or one of the special values * or all. If this key is unset, flatpak
-                   defaults to including just the current locale.
+                   defaults to including the extra-languages key and the current locale.
+                </para></listitem>
+            </varlistentry>
+            <varlistentry>
+                <term><varname>extra-languages</varname></term>
+                <listitem><para>
+                   This key is used when languages is not set, and it defines extra locale
+                   extensions on top of the system configured languages. The value is a
+                   semicolon-separated list of two-letter language codes.
                 </para></listitem>
             </varlistentry>
         </variablelist>

doc/reference/flatpak-sections.txt

@@ -47,6 +47,7 @@ flatpak_installation_remove_remote
 flatpak_installation_update_remote_sync
 flatpak_installation_cleanup_local_refs_sync
 flatpak_installation_get_config
+flatpak_installation_get_default_languages
 flatpak_installation_prune_local_repo
 flatpak_installation_remove_local_ref_sync
 flatpak_installation_set_config_sync

system-helper/flatpak-system-helper.c

@@ -1120,8 +1120,7 @@ handle_configure (FlatpakSystemHelper   *object,
       return TRUE;
     }
 
-  /* We only support this for now */
-  if (strcmp (arg_key, "languages") != 0)
+  if ((strcmp (arg_key, "languages") != 0) && (strcmp (arg_key, "extra-languages") != 0))
     {
       g_dbus_method_invocation_return_error (invocation, G_DBUS_ERROR, G_DBUS_ERROR_INVALID_ARGS,
                                              "Unsupported key: %s", arg_key);

tests/testlibrary.c

@@ -237,6 +237,69 @@ test_installation_config (void)
   g_assert_no_error (error);
 }
 
+static void
+configure_languages (void)
+{
+  char *argv[] = { "flatpak", "config", "--user", "--set", "languages", "de", NULL };
+
+  run_test_subprocess (argv, RUN_TEST_SUBPROCESS_DEFAULT);
+}
+
+static void
+clean_languages (void)
+{
+  char *argv[] = { "flatpak", "config", "--user", "--unset", "languages", NULL };
+
+  run_test_subprocess (argv, RUN_TEST_SUBPROCESS_DEFAULT);
+}
+
+static void
+test_languages_config (void)
+{
+  g_autoptr(FlatpakInstallation) inst = NULL;
+  g_autofree char *path = NULL;
+  g_autoptr(GFile) file = NULL;
+  g_autoptr(GError) error = NULL;
+  g_auto(GStrv) value = NULL;
+  gboolean res;
+
+  clean_languages ();
+  path = g_build_filename (g_get_user_data_dir (), "flatpak", NULL);
+  file = g_file_new_for_path (path);
+  inst = flatpak_installation_new_for_path (file, TRUE, NULL, &error);
+  g_assert_no_error (error);
+  g_assert_nonnull (inst);
+
+  value = flatpak_installation_get_default_languages (inst, &error);
+  g_assert_no_error (error);
+  g_assert_cmpstr (value[0], ==, "en");
+
+  res = flatpak_installation_set_config_sync (inst, "extra-languages", "en;pt", NULL, &error);
+  g_assert_no_error (error);
+  g_assert_true (res);
+
+  value = flatpak_installation_get_default_languages (inst, &error);
+  g_assert_no_error (error);
+  g_assert_cmpstr (value[0], ==, "en");
+  g_assert_cmpstr (value[1], ==, "pt");
+  g_assert_null (value[2]);
+
+  g_clear_pointer (&value, g_free);
+
+  res = flatpak_installation_set_config_sync (inst, "languages", "ar;es", NULL, &error);
+  g_assert_no_error (error);
+  g_assert_true (res);
+
+  value = flatpak_installation_get_default_languages (inst, &error);
+  g_assert_no_error (error);
+  g_assert_cmpstr (value[0], ==, "ar");
+  g_assert_cmpstr (value[1], ==, "es");
+  g_assert_null (value[2]);
+
+  g_clear_pointer (&value, g_free);
+  configure_languages ();
+}
+
 static void
 test_arches (void)
 {
@@ -1829,14 +1892,6 @@ setup_multiple_installations (void)
   add_extra_installation ("extra-installation-3", NULL, NULL, NULL);
 }
 
-static void
-configure_languages (void)
-{
-  char *argv[] = { "flatpak", "config", "--user", "--set", "languages", "de", NULL };
-
-  run_test_subprocess (argv, RUN_TEST_SUBPROCESS_DEFAULT);
-}
-
 static void
 setup_repo (void)
 {
@@ -1968,6 +2023,7 @@ global_setup (void)
   g_assert_cmpstr (g_get_user_runtime_dir (), ==, flatpak_runtimedir);
 
   g_setenv ("FLATPAK_SYSTEM_HELPER_ON_SESSION", "1", TRUE);
+  g_setenv ("LANGUAGE", "en", TRUE);
 
   test_bus = g_test_dbus_new (G_TEST_DBUS_NONE);
 
@@ -3635,6 +3691,7 @@ main (int argc, char *argv[])
   g_test_add_func ("/library/system-installation", test_system_installation);
   g_test_add_func ("/library/multiple-system-installation", test_multiple_system_installations);
   g_test_add_func ("/library/installation-config", test_installation_config);
+  g_test_add_func ("/library/languages-config", test_languages_config);
   g_test_add_func ("/library/arches", test_arches);
   g_test_add_func ("/library/ref", test_ref);
   g_test_add_func ("/library/list-remotes", test_list_remotes);