libotutil: Add ot_keyfile_get_value_with_default_group_optional()

Add ot_keyfile_get_value_with_default_group_optional() which allows
getting values from keys where the group is optional in the config
file. This is preparatory to add the sysroot.bootloader repo config
key, where the sysroot group is optional.

Closes: #1814
Approved by: jlebon

src/libotutil/ot-keyfile-utils.c

@@ -101,6 +101,42 @@ ot_keyfile_get_value_with_default (GKeyFile      *keyfile,
   return ret;
 }
 
+gboolean
+ot_keyfile_get_value_with_default_group_optional (GKeyFile      *keyfile,
+                                                  const char    *section,
+                                                  const char    *value,
+                                                  const char    *default_value,
+                                                  char         **out_value,
+                                                  GError       **error)
+{
+  gboolean ret = FALSE;
+  GError *local_error = NULL;
+  g_autofree char *ret_value = NULL;
+
+  g_return_val_if_fail (keyfile != NULL, ret);
+  g_return_val_if_fail (section != NULL, ret);
+  g_return_val_if_fail (value != NULL, ret);
+
+  if (!ot_keyfile_get_value_with_default (keyfile, section, value, default_value, &ret_value, &local_error))
+    {
+      if (g_error_matches (local_error, G_KEY_FILE_ERROR, G_KEY_FILE_ERROR_GROUP_NOT_FOUND))
+        {
+          g_clear_error (&local_error);
+          ret_value = g_strdup (default_value);
+        }
+      else
+        {
+          g_propagate_error (error, local_error);
+          goto out;
+        }
+    }
+
+  ret = TRUE;
+  ot_transfer_out_value(out_value, &ret_value);
+ out:
+  return ret;
+}
+
 /* Read the value of key as a string.  If the value string contains
  * zero or one of the separators and none of the others, read the
  * string as a NULL-terminated array out_value.  If the value string

src/libotutil/ot-keyfile-utils.h

@@ -44,6 +44,14 @@ ot_keyfile_get_value_with_default (GKeyFile      *keyfile,
                                    char         **out_value,
                                    GError       **error);
 
+gboolean
+ot_keyfile_get_value_with_default_group_optional (GKeyFile      *keyfile,
+                                                  const char    *section,
+                                                  const char    *value,
+                                                  const char    *default_value,
+                                                  char         **out_value,
+                                                  GError       **error);
+
 gboolean
 ot_keyfile_get_string_list_with_separator_choice (GKeyFile      *keyfile,
                                                   const char    *section,

tests/test-keyfile-utils.c

@@ -79,7 +79,6 @@ test_get_value_with_default (void)
   /* Avoid that g_return_val_if_fail causes the test to fail.  */
   always_fatal_mask = g_log_set_always_fatal (0);
 
-
   g_assert_false (ot_keyfile_get_value_with_default (g_keyfile,
                                                      NULL,
                                                      "value_foo",
@@ -124,11 +123,75 @@ test_get_value_with_default (void)
   g_clear_pointer (&out, g_free);
 
   g_assert_false (ot_keyfile_get_value_with_default (g_keyfile,
-                                                       "a_fake_section",
-                                                       "a_value_true",
-                                                       "no value",
-                                                       &out,
-                                                       &error));
+                                                     "a_fake_section",
+                                                     "a_value_true",
+                                                     "no value",
+                                                     &out,
+                                                     &error));
+  g_clear_error (&error);
+  g_clear_pointer (&out, g_free);
+}
+
+static void
+test_get_value_with_default_group_optional (void)
+{
+  g_autoptr(GError) error = NULL;
+  g_autofree char *out = NULL;
+  GLogLevelFlags always_fatal_mask;
+  const char *section = "section";
+
+/* Avoid that g_return_val_if_fail causes the test to fail.  */
+  always_fatal_mask = g_log_set_always_fatal (0);
+
+  g_assert_false (ot_keyfile_get_value_with_default_group_optional (g_keyfile,
+                                                                    NULL,
+                                                                    "value_foo",
+                                                                    "none",
+                                                                    &out,
+                                                                    &error));
+  g_clear_pointer (&out, g_free);
+  g_assert_false (ot_keyfile_get_value_with_default_group_optional (g_keyfile,
+                                                                    section,
+                                                                    NULL,
+                                                                    "none",
+                                                                    &out,
+                                                                    &error));
+  g_clear_pointer (&out, g_free);
+  g_assert_false (ot_keyfile_get_value_with_default_group_optional (g_keyfile,
+                                                                    section,
+                                                                    NULL,
+                                                                    "something",
+                                                                    &out,
+                                                                    &error));
+  g_clear_pointer (&out, g_free);
+
+  /* Restore the old mask.  */
+  g_log_set_always_fatal (always_fatal_mask);
+
+  g_assert (ot_keyfile_get_value_with_default_group_optional (g_keyfile,
+                                                              section,
+                                                              "value_foo",
+                                                              "none",
+                                                              &out,
+                                                              &error));
+  g_assert_cmpstr (out, ==, "foo");
+  g_clear_pointer (&out, g_free);
+
+  g_assert (ot_keyfile_get_value_with_default_group_optional (g_keyfile,
+                                                              section,
+                                                              "a_not_existing_value",
+                                                              "correct",
+                                                              &out,
+                                                              &error));
+  g_assert_cmpstr (out, ==, "correct");
+  g_clear_pointer (&out, g_free);
+
+  g_assert (ot_keyfile_get_value_with_default_group_optional (g_keyfile,
+                                                              "an_optional_section",
+                                                              "a_value_true",
+                                                              "no value",
+                                                              &out,
+                                                              &error));
   g_clear_error (&error);
   g_clear_pointer (&out, g_free);
 }
@@ -191,6 +254,7 @@ int main (int argc, char **argv)
 
   g_test_add_func ("/keyfile-utils/get-boolean-with-default", test_get_boolean_with_default);
   g_test_add_func ("/keyfile-utils/get-value-with-default", test_get_value_with_default);
+  g_test_add_func ("/keyfile-utils/get-value-with-default-group-optional", test_get_value_with_default_group_optional);
   g_test_add_func ("/keyfile-utils/copy-group", test_copy_group);
 
   ret = g_test_run();