keyfile: add nm_keyfile_handler_data_warn_get() and construct message lazy

Add an accessor for the warning event.

Also, as we now have an accessor, we can construct the warning
message only if it actually needed.

3 files changed, 68 insertions, 13 deletions

diff --git a/shared/nm-keyfile/nm-keyfile-internal.h b/shared/nm-keyfile/nm-keyfile-internal.h
index 719e5501aa..be0f800a52 100644
--- a/shared/nm-keyfile/nm-keyfile-internal.h
+++ b/shared/nm-keyfile/nm-keyfile-internal.h
@@ -119,7 +119,9 @@ GKeyFile *nm_keyfile_write (NMConnection *connection,
  */
 typedef struct {
 	NMKeyfileWarnSeverity severity;
-	const char *message;
+	char *message;
+	const char *fmt;
+	va_list ap;
 } NMKeyfileHandlerDataWarn;
 
 /**
@@ -160,6 +162,12 @@ void nm_keyfile_handler_data_get_context (const NMKeyfileHandlerData *handler_da
                                           NMSetting **out_cur_setting,
                                           const char **out_cur_property_name);
 
+void nm_keyfile_handler_data_warn_get (const NMKeyfileHandlerData *handler_data,
+                                       const char **out_message,
+                                       NMKeyfileWarnSeverity *out_severity);
+
+const char *_nm_keyfile_handler_data_warn_get_message (const NMKeyfileHandlerData *handler_data);
+
 /*****************************************************************************/
 
 char *nm_keyfile_plugin_kf_get_string (GKeyFile *kf, const char *group, const char *key, GError **error);
diff --git a/shared/nm-keyfile/nm-keyfile.c b/shared/nm-keyfile/nm-keyfile.c
index b6a89a2e4e..3b198d1ae3 100644
--- a/shared/nm-keyfile/nm-keyfile.c
+++ b/shared/nm-keyfile/nm-keyfile.c
@@ -103,12 +103,14 @@ _key_file_handler_data_init_write (NMKeyfileHandlerData *handler_data,
 	                             &info->error);
 }
 
+_nm_printf (5, 6)
 static void
 _handle_warn (KeyfileReaderInfo *info,
               const char *kf_key,
               const char *cur_property,
               NMKeyfileWarnSeverity severity,
-              char *message)
+              const char *fmt,
+              ...)
 {
 	NMKeyfileHandlerData handler_data;
 
@@ -119,15 +121,21 @@ _handle_warn (KeyfileReaderInfo *info,
 	                                  cur_property);
 	handler_data.warn = (NMKeyfileHandlerDataWarn) {
 		.severity = severity,
-		.message = message,
+		.message  = NULL,
+		.fmt      = fmt,
 	};
 
+	va_start (handler_data.warn.ap, fmt);
+
 	info->read_handler (info->keyfile,
 	                    info->connection,
 	                    NM_KEYFILE_HANDLER_TYPE_WARN,
 	                    &handler_data,
 	                    info->user_data);
-	g_free (message);
+
+	va_end (handler_data.warn.ap);
+
+	g_free (handler_data.warn.message);
 }
 
 #define handle_warn(arg_info, arg_kf_key, arg_property_name, arg_severity, ...) \
@@ -141,7 +149,7 @@ _handle_warn (KeyfileReaderInfo *info,
 			              (arg_kf_key), \
 			              (arg_property_name), \
 			              (arg_severity), \
-			              g_strdup_printf (__VA_ARGS__)); \
+			              __VA_ARGS__); \
 		} \
 		_info->error == NULL; \
 	})
@@ -4393,3 +4401,40 @@ nm_keyfile_handler_data_get_context (const NMKeyfileHandlerData *handler_data,
 	NM_SET_OUT (out_cur_setting, handler_data->cur_setting);
 	NM_SET_OUT (out_cur_property_name, handler_data->cur_property);
 }
+
+const char *
+_nm_keyfile_handler_data_warn_get_message (const NMKeyfileHandlerData *handler_data)
+{
+	nm_assert (handler_data);
+	nm_assert (handler_data->type == NM_KEYFILE_HANDLER_TYPE_WARN);
+
+	if (!handler_data->warn.message) {
+		/* we cast the const away. @handler_data is const w.r.t. visible mutations
+		 * from POV of the user. Internally, we construct the message in
+		 * a lazy manner. It's like a mutable field in C++. */
+		NM_PRAGMA_WARNING_DISABLE ("-Wformat-nonliteral")
+		((NMKeyfileHandlerData *) handler_data)->warn.message = g_strdup_vprintf (handler_data->warn.fmt,
+		                                                                          ((NMKeyfileHandlerData *) handler_data)->warn.ap);
+		NM_PRAGMA_WARNING_REENABLE
+	}
+	return handler_data->warn.message;
+}
+
+/**
+ * nm_keyfile_handler_data_warn_get:
+ * @handler_data: the #NMKeyfileHandlerData for a %NM_KEYFILE_HANDLER_TYPE_WARN
+ *  event.
+ * @out_message: (out) (allow-none) (transfer none): the warning message.
+ * @out_severity: (out) (allow-none): the #NMKeyfileWarnSeverity warning severity.
+ */
+void
+nm_keyfile_handler_data_warn_get (const NMKeyfileHandlerData *handler_data,
+                                  const char **out_message,
+                                  NMKeyfileWarnSeverity *out_severity)
+{
+	g_return_if_fail (handler_data);
+	g_return_if_fail (handler_data->type == NM_KEYFILE_HANDLER_TYPE_WARN);
+
+	NM_SET_OUT (out_message, _nm_keyfile_handler_data_warn_get_message (handler_data));
+	NM_SET_OUT (out_severity, handler_data->warn.severity);
+}
diff --git a/src/settings/plugins/keyfile/nms-keyfile-reader.c b/src/settings/plugins/keyfile/nms-keyfile-reader.c
index 520053c191..2459be483f 100644
--- a/src/settings/plugins/keyfile/nms-keyfile-reader.c
+++ b/src/settings/plugins/keyfile/nms-keyfile-reader.c
@@ -17,11 +17,15 @@
 /*****************************************************************************/
 
 static const char *
-_fmt_warn (const char *group, NMSetting *setting, const char *property_name, const char *message, char **out_message)
+_fmt_warn (const NMKeyfileHandlerData *handler_data, char **out_message)
 {
-	const char *setting_name = setting ? nm_setting_get_name (setting) : NULL;
+	const char *group = handler_data->kf_group_name;
+	const char *message = _nm_keyfile_handler_data_warn_get_message (handler_data);
 
 	if (group) {
+		NMSetting *setting = handler_data->cur_setting;
+		const char *property_name = handler_data->cur_property;
+		const char *setting_name = setting ? nm_setting_get_name (setting) : NULL;
 		char *res;
 
 		if (setting_name) {
@@ -37,8 +41,9 @@ _fmt_warn (const char *group, NMSetting *setting, const char *property_name, con
 			res = g_strdup_printf ("%s: %s", group, message);
 		*out_message = res;
 		return res;
-	} else
-		return message;
+	}
+
+	return message;
 }
 
 typedef struct {
@@ -76,10 +81,7 @@ _handler_read (GKeyFile *keyfile,
 		        NULL,
 		        nm_connection_get_uuid (connection),
 		        "keyfile: %s",
-		        _fmt_warn (handler_data->kf_group_name,
-		                   handler_data->cur_setting,
-		                   handler_data->cur_property,
-		                   warn_data->message,
+		        _fmt_warn (handler_data,
 		                   &message_free));
 		g_free (message_free);
 		return TRUE;