iox-eclipse-iceoryx#1969 Add 'in_place_t' ctors for 'expected'

iceoryx_hoofs/test/moduletests/test_vocabulary_expected.cpp

@@ -477,6 +477,22 @@ TEST_F(expected_test, ErrorTypeOnlyMoveAssignmentLeadsToMovedSource)
     EXPECT_EQ(sutDestination.get_error().m_b, B);
 }
 
+TEST_F(expected_test, CreateFromInPlaceTypeLeadsToValidErrorOnlySut)
+{
+    ::testing::Test::RecordProperty("TEST_ID", "91a8ad7f-4843-4bd9-a56b-0561ae6b56cb");
+    expected<TestError> sut{in_place};
+    ASSERT_THAT(sut.has_error(), Eq(false));
+}
+
+TEST_F(expected_test, CreateFromInPlaceTypeLeadsToValidSut)
+{
+    ::testing::Test::RecordProperty("TEST_ID", "3a527c62-aaea-44ae-9b99-027c19d032b5");
+    constexpr int VALUE = 42;
+    expected<int, TestError> sut{in_place, VALUE};
+    ASSERT_THAT(sut.has_error(), Eq(false));
+    EXPECT_THAT(sut.value(), Eq(VALUE));
+}
+
 TEST_F(expected_test, CreateFromEmptySuccessTypeLeadsToValidSut)
 {
     ::testing::Test::RecordProperty("TEST_ID", "0204f08f-fb6d-45bb-aac7-fd14152ab1bf");

iceoryx_hoofs/vocabulary/include/iox/detail/expected.inl

@@ -101,6 +101,13 @@ inline expected<ValueType, ErrorType>::expected(expected<ValueType, ErrorType>&&
 {
 }
 
+template <typename ValueType, typename ErrorType>
+template <typename... Targs>
+inline expected<ValueType, ErrorType>::expected(in_place_t, Targs&&... args) noexcept
+    : m_store(in_place_index<VALUE_INDEX>(), std::forward<Targs>(args)...)
+{
+}
+
 template <typename ValueType, typename ErrorType>
 inline expected<ValueType, ErrorType>&
 expected<ValueType, ErrorType>::operator=(expected<ValueType, ErrorType>&& rhs) noexcept
@@ -264,6 +271,11 @@ inline expected<ErrorType>::expected(const success<void>) noexcept
 {
 }
 
+template <typename ErrorType>
+inline expected<ErrorType>::expected(in_place_t) noexcept
+{
+}
+
 template <typename ErrorType>
 inline expected<ErrorType>::expected(expected<ErrorType>&& rhs) noexcept
     : m_store(std::move(rhs.m_store))
@@ -292,6 +304,7 @@ inline expected<ErrorType>::expected(error<ErrorType>&& errorValue) noexcept
     : m_store(in_place_index<ERROR_INDEX>(), std::move(errorValue.value))
 {
 }
+
 // AXIVION DISABLE STYLE AutosarC++19_03-A16.0.1: Required for Windows due to MSVC deficiencies
 #if defined(_WIN32)
 template <typename ErrorType>

iceoryx_hoofs/vocabulary/include/iox/expected.hpp

@@ -195,6 +195,11 @@ class IOX_NO_DISCARD expected<ErrorType> final : public FunctionalInterface<expe
     // NOLINTNEXTLINE(hicpp-explicit-conversions)
     expected(const success<void>) noexcept;
 
+    /// @brief Creates an expected which is signaling success. This mirrors the c'tor for the 'expected' with a
+    /// 'ValueType'.
+    /// @param[in] in_place_t compile time variable to distinguish between constructors with certain behavior
+    explicit expected(in_place_t) noexcept;
+
     /// @brief  constructs an expected which is signaling an error and stores the
     ///         error value provided by errorValue
     /// @param[in] errorValue error value which will be stored in the expected
@@ -277,6 +282,13 @@ class IOX_NO_DISCARD expected<ValueType, ErrorType> final
     /// ValueType or ErrorType to correctly invalidate the stored object
     expected(expected&& rhs) noexcept;
 
+    /// @brief Creates an expected which is signaling success and perfectly forwards
+    ///        the args to the constructor of ValueType
+    /// @param[in] in_place_t compile time variable to distinguish between constructors with certain behavior
+    /// @param[in] args... arguments which will be forwarded to the 'ValueType' constructor
+    template <typename... Targs>
+    explicit expected(in_place_t, Targs&&... args) noexcept;
+
     /// @brief calls the destructor of the success value or error value - depending on what
     ///         is stored in the expected
     ~expected() noexcept = default;