From e0d87f70d87a63aa55a11ecb91f8d355767d61bd Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@qt.io>
Date: Tue, 21 May 2024 10:53:43 +0200
Subject: [PATCH] Replace QUuid::toRfc4122() with toBytes() where possible
MIME-Version: 1.0
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They're content-equivalent, except that the latter doesn't have to
allocate a return value on the heap.

Pick-to: 6.7
Change-Id: Ifcae47b487c80c2bac02900f08393b386cfe806c
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
---
 src/corelib/kernel/qcore_foundation.mm | 11 +++++++----
 src/corelib/plugin/quuid.cpp           |  2 +-
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/corelib/kernel/qcore_foundation.mm b/src/corelib/kernel/qcore_foundation.mm
index a31040944f1..6d2451e078e 100644
--- a/src/corelib/kernel/qcore_foundation.mm
+++ b/src/corelib/kernel/qcore_foundation.mm
@@ -300,8 +300,8 @@ QUuid QUuid::fromCFUUID(CFUUIDRef uuid)
 */
 CFUUIDRef QUuid::toCFUUID() const
 {
-    const QByteArray bytes = toRfc4122();
-    return CFUUIDCreateFromUUIDBytes(0, *reinterpret_cast<const CFUUIDBytes *>(bytes.constData()));
+    const auto bytes = toBytes();
+    return CFUUIDCreateFromUUIDBytes(0, *reinterpret_cast<const CFUUIDBytes *>(&bytes));
 }
 
 /*!
@@ -333,8 +333,11 @@ QUuid QUuid::fromNSUUID(const NSUUID *uuid)
 */
 NSUUID *QUuid::toNSUUID() const
 {
-    const QByteArray bytes = toRfc4122();
-    return [[[NSUUID alloc] initWithUUIDBytes:*reinterpret_cast<const uuid_t *>(bytes.constData())] autorelease];
+    const auto bytes = toBytes();
+    static_assert(sizeof bytes == sizeof(uuid_t));
+    uuid_t u;
+    memcpy(&u, &bytes, sizeof(uuid_t));
+    return [[[NSUUID alloc] initWithUUIDBytes:u] autorelease];
 }
 
 // ----------------------------------------------------------------------------
diff --git a/src/corelib/plugin/quuid.cpp b/src/corelib/plugin/quuid.cpp
index 42f21eea88c..8c3b758aaca 100644
--- a/src/corelib/plugin/quuid.cpp
+++ b/src/corelib/plugin/quuid.cpp
@@ -119,7 +119,7 @@ static QUuid _q_uuidFromHex(const char *src)
 static QUuid createFromName(const QUuid &ns, const QByteArray &baseData, QCryptographicHash::Algorithm algorithm, int version)
 {
     QCryptographicHash hash(algorithm);
-    hash.addData(ns.toRfc4122());
+    hash.addData(QByteArrayView{ns.toBytes()});
     hash.addData(baseData);
     QByteArrayView hashResult = hash.resultView();
     Q_ASSERT(hashResult.size() >= 16);