From a0c7ca37736336c6b0ab0c2bf0523bbf05313298 Mon Sep 17 00:00:00 2001
From: Thiago Macieira <thiago.macieira@intel.com>
Date: Thu, 15 May 2025 07:23:44 -0700
Subject: [PATCH] QTest::CrashHandler: use string_view for writeToStderr() for
 the inputs

For regular strings, it'll call strlen() for us, removing the need of
our doing it. We just have to remove the one case where we were passing
iovec into it: make asyncSafeToString() return a string_view too.

Change-Id: I7d17e5c4525637df23f1fffd5e5c381632386f49
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Ahmad Samir <a.samirh78@gmail.com>
---
 src/testlib/qtestcrashhandler_unix.cpp | 27 +++++++++-----------------
 1 file changed, 9 insertions(+), 18 deletions(-)

diff --git a/src/testlib/qtestcrashhandler_unix.cpp b/src/testlib/qtestcrashhandler_unix.cpp
index 92ad16ceb97..8a24b96e3dc 100644
--- a/src/testlib/qtestcrashhandler_unix.cpp
+++ b/src/testlib/qtestcrashhandler_unix.cpp
@@ -17,6 +17,7 @@
 // Broken implementation, causes link failures just by #include'ing!
 #  undef __cpp_lib_to_chars     // in case <version> was included
 #endif
+#include <string_view>
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -118,15 +119,11 @@ using OldActionsArray = std::array<struct sigaction, fatalSignals.size()>;
 
 template <typename... Args> static ssize_t writeToStderr(Args &&... args)
 {
-    auto makeIovec = [](auto &&arg) {
-        if constexpr (std::is_same_v<std::decay_t<decltype(arg)>, iovec>) {
-            return arg;
-        } else {
-            struct iovec r = {};
-            r.iov_base = const_cast<char *>(arg);
-            r.iov_len = strlen(arg);
-            return r;
-        }
+    auto makeIovec = [](std::string_view arg) {
+        struct iovec r = {};
+        r.iov_base = const_cast<char *>(arg.data());
+        r.iov_len = arg.size();
+        return r;
     };
     struct iovec vec[] = { makeIovec(std::forward<Args>(args))... };
     return ::writev(STDERR_FILENO, vec, std::size(vec));
@@ -145,7 +142,7 @@ struct AsyncSafeIntBuffer
     AsyncSafeIntBuffer(Qt::Initialization) {}       // leaves array uninitialized
 };
 
-struct iovec asyncSafeToString(int n, AsyncSafeIntBuffer &&result = Qt::Uninitialized)
+std::string_view asyncSafeToString(int n, AsyncSafeIntBuffer &&result = Qt::Uninitialized)
 {
     char *ptr = result.array.data();
     if (false) {
@@ -185,10 +182,7 @@ struct iovec asyncSafeToString(int n, AsyncSafeIntBuffer &&result = Qt::Uninitia
     // this isn't necessary, it just helps in the debugger
     *ptr = '\0';
 #endif
-    struct iovec r;
-    r.iov_base = result.array.data();
-    r.iov_len = ptr - result.array.data();
-    return r;
+    return std::string_view(result.array.data(), ptr - result.array.data());
 };
 } // unnamed namespace
 
@@ -433,10 +427,7 @@ printCrashingSignalInfo(T *info)
         int shift = sizeof(quintptr) * 8 - 4;
         for (size_t i = 0; i < sizeof(quintptr) * 2; ++i, shift -= 4)
             r[i] = QtMiscUtils::toHexLower(u >> shift);
-        struct iovec vec;
-        vec.iov_base = r.data();
-        vec.iov_len = r.size();
-        return vec;
+        return std::string_view(r.data(), r.size());
     };
     writeToStderr(", code ", asyncSafeToString(info->si_code),
                   ", for address 0x", toHexString(quintptr(info->si_addr)));