Create Message

Message is a wrapper/utility class that allows to easily create and
store a string based on a set of given arguments.

Re ECFLOW-1931

Author: marcosbento

ACore/CMakeLists.txt

@@ -39,6 +39,7 @@ set(srcs
   src/ecflow/core/Indentor.hpp
   src/ecflow/core/Log.hpp
   src/ecflow/core/LogVerification.hpp
+  src/ecflow/core/Message.hpp
   src/ecflow/core/NOrder.hpp
   src/ecflow/core/NState.hpp
   src/ecflow/core/NodePath.hpp
@@ -149,6 +150,7 @@ set(test_srcs
   test/TestFile.cpp
   test/TestGetUserDetails.cpp
   test/TestLog.cpp
+  test/TestMessage.cpp
   test/TestMigration.cpp
   test/TestNodePath.cpp
   test/TestPasswdFile.cpp

ACore/src/ecflow/core/Message.hpp

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2009- ECMWF.
+ *
+ * This software is licensed under the terms of the Apache Licence version 2.0
+ * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+ * In applying this licence, ECMWF does not waive the privileges and immunities
+ * granted to it by virtue of its status as an intergovernmental organisation
+ * nor does it submit to any jurisdiction.
+ */
+
+#ifndef ecflow_core_Message_HPP
+#define ecflow_core_Message_HPP
+
+#include <sstream>
+#include <string>
+
+namespace ecf {
+
+///
+/// \brief Message is a utility class that easily creates a string-based Message from an arbitrary set of inputs
+///
+/// The goal is to facilitate the construction/formatting of messages for error handling and logging.
+/// A Message implicitly allows conversion to std::string, and provides the streaming operator<<.
+///
+class Message {
+public:
+    template <typename... ARGS>
+    explicit Message(ARGS&&... args) {
+        ((buffer << std::forward<ARGS>(args)), ...);
+    }
+
+    [[nodiscard]] std::string str() const { return buffer.str(); }
+    [[nodiscard]] operator std::string() const { return buffer.str(); }
+
+private:
+    std::ostringstream buffer;
+};
+
+inline std::ostream& operator<<(std::ostream& o, const Message& m) {
+    o << std::string(m);
+    return o;
+}
+
+} // namespace ecf
+
+#endif /* ecflow_core_Message_HPP */

ACore/test/TestMessage.cpp

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2009- ECMWF.
+ *
+ * This software is licensed under the terms of the Apache Licence version 2.0
+ * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+ * In applying this licence, ECMWF does not waive the privileges and immunities
+ * granted to it by virtue of its status as an intergovernmental organisation
+ * nor does it submit to any jurisdiction.
+ */
+
+#include <iostream>
+
+#include <boost/test/unit_test.hpp>
+
+#include "ecflow/core/Message.hpp"
+
+BOOST_AUTO_TEST_SUITE(U_Core)
+
+BOOST_AUTO_TEST_SUITE(T_Message)
+
+BOOST_AUTO_TEST_CASE(test_message_can_create_from_various_arguments) {
+    using namespace ecf;
+    using namespace std::string_literals;
+
+    BOOST_CHECK_EQUAL(Message().str(), ""s);
+    BOOST_CHECK_EQUAL(Message("a", ' ', "1").str(), "a 1"s);
+    BOOST_CHECK_EQUAL(Message("a", ' ', "1.01").str(), "a 1.01"s);
+    BOOST_CHECK_EQUAL(Message("a", ' ', 1).str(), "a 1"s);
+    BOOST_CHECK_EQUAL(Message("a", ' ', 1.01).str(), "a 1.01"s);
+    BOOST_CHECK_EQUAL(Message("a", ' ', true).str(), "a 1"s);
+    BOOST_CHECK_EQUAL(Message("a", Message("b", 'c')).str(), "abc"s);
+}
+
+BOOST_AUTO_TEST_CASE(test_message_can_convert_to_string) {
+    using namespace ecf;
+    using namespace std::string_literals;
+
+    std::string s = Message("a", Message("b", 'c'));
+    BOOST_CHECK_EQUAL(s, "abc"s);
+}
+
+BOOST_AUTO_TEST_CASE(test_message_can_stream) {
+    using namespace ecf;
+    using namespace std::string_literals;
+
+    std::ostringstream oss;
+    oss << Message("a", Message("b", 'c'));
+
+    BOOST_CHECK_EQUAL(oss.str(), "abc"s);
+}
+
+BOOST_AUTO_TEST_SUITE_END()
+
+BOOST_AUTO_TEST_SUITE_END()