From 9043b32bb1835628c5a1d8be4a271c848443c629 Mon Sep 17 00:00:00 2001
From: Daniel Wilhelm <daniel@wili.li>
Date: Tue, 24 May 2016 22:10:57 +0200
Subject: 8.1

---
 zen/scope_guard.h | 64 +++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 43 insertions(+), 21 deletions(-)

(limited to 'zen/scope_guard.h')

diff --git a/zen/scope_guard.h b/zen/scope_guard.h
index 67eb3053..f8c32127 100644
--- a/zen/scope_guard.h
+++ b/zen/scope_guard.h
@@ -22,7 +22,7 @@ inline int getUncaughtExceptionCount() { return std::uncaught_exceptions(); }
 #ifdef ZEN_LINUX
     static_assert(__GNUC__ < 5 || (__GNUC__ == 5 && (__GNUC_MINOR__ < 3 || (__GNUC_MINOR__ == 3 && __GNUC_PATCHLEVEL__ <= 1))), "check std::uncaught_exceptions support");
 #else
-    static_assert(__clang_major__ < 7 || (__clang_major__ == 7 && __clang_minor__ <= 0), "check std::uncaught_exceptions support");
+    static_assert(__clang_major__ < 7 || (__clang_major__ == 7 && __clang_minor__ <= 3), "check std::uncaught_exceptions support");
 #endif
 
 namespace __cxxabiv1
@@ -60,6 +60,47 @@ enum class ScopeGuardRunMode
 };
 
 
+template <ScopeGuardRunMode runMode, typename F>
+struct ScopeGuardDestructor;
+
+//specialize scope guard destructor code and get rid of those pesky MSVC "4127 conditional expression is constant"
+template <typename F>
+struct ScopeGuardDestructor<ScopeGuardRunMode::ON_EXIT, F>
+{
+    static void run(F& fun, int exeptionCountOld)
+    {
+		(void)exeptionCountOld; //silence unused parameter warning
+        try { fun(); }
+        catch (...) { assert(false); } //consistency: don't expect exceptions for ON_EXIT even if "!failed"!
+    }
+};
+
+
+template <typename F>
+struct ScopeGuardDestructor<ScopeGuardRunMode::ON_SUCCESS, F>
+{
+    static void run(F& fun, int exeptionCountOld)
+    {
+        const bool failed = getUncaughtExceptionCount() > exeptionCountOld;
+        if (!failed)
+            fun(); //throw X
+    }
+};
+
+
+template <typename F>
+struct ScopeGuardDestructor<ScopeGuardRunMode::ON_FAIL, F>
+{
+    static void run(F& fun, int exeptionCountOld)
+    {
+        const bool failed = getUncaughtExceptionCount() > exeptionCountOld;
+        if (failed)
+            try { fun(); }
+            catch (...) { assert(false); }
+    }
+};
+
+
 template <ScopeGuardRunMode runMode, typename F>
 class ScopeGuard
 {
@@ -74,26 +115,7 @@ public:
     ~ScopeGuard() noexcept(runMode != ScopeGuardRunMode::ON_SUCCESS)
     {
         if (!dismissed)
-        {
-#ifdef _MSC_VER
-#pragma warning(suppress: 4127) //"conditional expression is constant"
-#endif
-            if (runMode != ScopeGuardRunMode::ON_EXIT)
-            {
-                const bool failed = getUncaughtExceptionCount() > exeptionCount;
-                if ((runMode == ScopeGuardRunMode::ON_FAIL) != failed)
-                    return;
-            }
-
-#ifdef _MSC_VER
-#pragma warning(suppress: 4127) //"conditional expression is constant"
-#endif
-            if (runMode == ScopeGuardRunMode::ON_SUCCESS)
-                fun_(); //throw X
-            else
-                try { fun_(); }
-                catch (...) { assert(false); } //consistency: don't expect exceptions for ON_EXIT even if "!failed"!
-        }
+            ScopeGuardDestructor<runMode, F>::run(fun_, exeptionCount);
     }
 
     void dismiss() { dismissed = true; }
-- 
cgit