scope_fail

Author: robert-andrzejuk

include/beman/scope/scope.hpp

@@ -444,6 +444,27 @@ class ReleasableExecuteWhenNoException
 };
 
 
+//======
+
+class ReleasableExecuteOnlyWhenException
+{
+public:
+    [[nodiscard]] bool operator()() const noexcept(noexcept(std::uncaught_exceptions()))
+    {
+        return m_uncaught_on_creation < std::uncaught_exceptions();
+    }
+
+
+    void release()
+    {
+        m_uncaught_on_creation = INT_MAX;
+    }
+
+private:
+    int m_uncaught_on_creation = std::uncaught_exceptions();
+};
+
+
 //==================================================================================================
 
 // --- type aliases ---
@@ -457,6 +478,9 @@ using scope_success = scope_guard<ExitFunc,
                                   ReleasableExecuteWhenNoException,
                                   exception_during_constuction_behaviour::dont_invoke_exit_func>;
 
+template<class ExitFunc>
+using scope_fail =
+      scope_guard<ExitFunc, ReleasableExecuteOnlyWhenException, exception_during_constuction_behaviour::invoke_exit_func>;
 
 } // namespace beman::scope
 

tests/scope_fail.test.cpp

@@ -9,7 +9,8 @@
 #define CATCH_CONFIG_MAIN
 #include <catch2/catch_all.hpp>
 
-using namespace beman::scope;
+using beman::scope::scope_fail;
+using beman::scope::scope_success;
 
 TEST_CASE("scope_fail runs handler on exception", "[scope_fail]") {
     bool triggered = false;
@@ -187,11 +188,11 @@ TEST_CASE("scope_fail coexists with scope_success", "[scope_fail][advanced]") {
     std::string output;
 
     try {
-        std::experimental::scope_success success([&]() {
+        scope_success success([&]() {
             output += "success ";
         });
 
-        std::experimental::scope_fail fail([&]() {
+        scope_fail fail([&]() {
             output += "fail ";
         });