Merge pull request #873 from londey/narrow-throw

Changed implementation of gsl::narrow to throw gsl::narrowing_error

include/gsl/gsl_util

@@ -96,6 +96,10 @@ constexpr T narrow_cast(U&& u) noexcept
     return static_cast<T>(std::forward<U>(u));
 }
 
+struct narrowing_error : public std::exception
+{
+};
+
 namespace details
 {
     template <class T, class U>
@@ -115,9 +119,9 @@ constexpr
 T narrow(U u) noexcept(false)
 {
     T t = narrow_cast<T>(u);
-    if (static_cast<U>(t) != u) gsl::details::terminate();
+    if (static_cast<U>(t) != u) throw narrowing_error{};
     if (!details::is_same_signedness<T, U>::value && ((t < T{}) != (u < U{})))
-        gsl::details::terminate();
+        throw narrowing_error{};
     return t;
 }
 

include/gsl/span

@@ -19,7 +19,6 @@
 
 #include <gsl/gsl_assert> // for Expects
 #include <gsl/gsl_byte>   // for byte
-#include <gsl/gsl_util>   // for narrow_cast, narrow
 
 #include <array>       // for array
 #include <cstddef>     // for ptrdiff_t, size_t, nullptr_t

tests/CMakeLists.txt

@@ -264,5 +264,4 @@ function(add_gsl_test_noexcept name)
     set_property(TARGET ${name} PROPERTY FOLDER "GSL_tests_noexcept")
 endfunction()
 
-add_gsl_test_noexcept(no_exception_throw_tests)
 add_gsl_test_noexcept(no_exception_ensure_tests)

tests/no_exception_throw_tests.cpp

@@ -1,48 +0,0 @@
-///////////////////////////////////////////////////////////////////////////////
-//
-// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
-//
-// This code is licensed under the MIT License (MIT).
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-//
-///////////////////////////////////////////////////////////////////////////////
-
-#include <cstdlib>        // for std::exit
-#include <gsl/gsl_assert> // for get_terminate
-#include <gsl/gsl_util>   // for narrow
-
-int narrow_no_throw()
-{
-    const long long bigNumber = 0x0fffffffffffffff;
-    return gsl::narrow<int>(bigNumber);
-}
-
-[[noreturn]] void test_terminate() { std::exit(0); }
-
-void setup_termination_handler() noexcept
-{
-#if defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
-
-    auto& handler = gsl::details::get_terminate_handler();
-    handler = &test_terminate;
-
-#else
-
-    std::set_terminate(test_terminate);
-
-#endif
-}
-
-int main()
-{
-    setup_termination_handler();
-    narrow_no_throw();
-    return -1;
-}

tests/utils_tests.cpp

@@ -29,7 +29,6 @@ using namespace gsl;
 
 namespace
 {
-static constexpr char deathstring[] = "Expected Death";
 void f(int& i) { i += 1; }
 static int j = 0;
 void g() { j += 1; }
@@ -104,17 +103,12 @@ TEST(utils_tests, narrow_cast)
 
 TEST(utils_tests, narrow)
 {
-    std::set_terminate([] {
-        std::cerr << "Expected Death. narrow";
-        std::abort();
-    });
-
     int n = 120;
     const char c = narrow<char>(n);
     EXPECT_TRUE(c == 120);
 
     n = 300;
-    EXPECT_DEATH(narrow<char>(n), deathstring);
+    EXPECT_THROW(narrow<char>(n), narrowing_error);
 
     const auto int32_max = std::numeric_limits<int32_t>::max();
     const auto int32_min = std::numeric_limits<int32_t>::min();
@@ -123,14 +117,13 @@ TEST(utils_tests, narrow)
     EXPECT_TRUE(narrow<uint32_t>(int32_t(1)) == 1);
     EXPECT_TRUE(narrow<uint32_t>(int32_max) == static_cast<uint32_t>(int32_max));
 
-    EXPECT_DEATH(narrow<uint32_t>(int32_t(-1)), deathstring);
+    EXPECT_THROW(narrow<uint32_t>(int32_t(-1)), narrowing_error);
-    EXPECT_DEATH(narrow<uint32_t>(int32_min), deathstring);
+    EXPECT_THROW(narrow<uint32_t>(int32_min), narrowing_error);
 
     n = -42;
-    EXPECT_DEATH(narrow<unsigned>(n), deathstring);
+    EXPECT_THROW(narrow<unsigned>(n), narrowing_error);
 
 #if GSL_CONSTEXPR_NARROW
     static_assert(narrow<char>(120) == 120, "Fix GSL_CONSTEXPR_NARROW");
 #endif
-
 }