From a1cbca44ef40d89f1ff9182e4014f9b8594330d5 Mon Sep 17 00:00:00 2001
From: Timur Pocheptsov <timur.pocheptsov@qt.io>
Date: Mon, 7 Sep 2020 08:24:59 +0200
Subject: [PATCH] TLS utils - move runtime check to compile time
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While it's possible to instantiate safe_delete using a nullptr, the
check in if-statement is 99.9(9) % of time redundant and equal
to if (true && object). Some compilers will issue a compilation
error (if warnings are treated as errors for example).

Change-Id: Ib593dc53deb6d2e4b77ea5c896610dc536c61b7c
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
---
 src/network/ssl/qtls_utils_p.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/network/ssl/qtls_utils_p.h b/src/network/ssl/qtls_utils_p.h
index 6777c1cbdbd..ceca3030d62 100644
--- a/src/network/ssl/qtls_utils_p.h
+++ b/src/network/ssl/qtls_utils_p.h
@@ -72,14 +72,18 @@ namespace QTlslUtils
 template <class NativeTlsType, void (*Deleter)(NativeTlsType *)>
 void safe_delete(NativeTlsType *object)
 {
-    if (object && Deleter)
+    static_assert (Deleter, "safe_delete: invalid (nullptr) function pointer provided");
+
+    if (object)
         Deleter(object);
 }
 
 template<class NativeTlsType, int ok, int (*Deleter)(NativeTlsType *)>
 void safe_delete(NativeTlsType *object)
 {
-    if (Deleter && object) {
+    static_assert (Deleter, "safe_delete: invalid (nullptr) function pointer provided");
+
+    if (object) {
         if (Deleter(object) != ok) {
             qCWarning(lcSsl, "Failed to free a resource.");
 #if QT_CONFIG(openssl) // || wolfssl later