From 6990f23813bc14be791838949dd93b5b33b40b77 Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@qt.io>
Date: Thu, 23 Feb 2023 21:13:25 +0100
Subject: [PATCH] Long live QMessageAuthenticationCode::resultView()!
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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Use it in a few places.

[ChangeLog][QtCore][QMessageAuthenticationCode] Added
QCryptographicHash-style resultView().

Change-Id: I745d71f86f9c19c9a9aabb2021c6617775dab1cf
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
---
 src/corelib/tools/qcryptographichash.cpp      | 21 ++++++++++++++++---
 .../tools/qmessageauthenticationcode.h        |  1 +
 src/plugins/tls/openssl/qdtls_openssl.cpp     |  2 +-
 .../tst_qmessageauthenticationcode.cpp        | 12 +++++------
 4 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/src/corelib/tools/qcryptographichash.cpp b/src/corelib/tools/qcryptographichash.cpp
index 86e1de7059..8ada1277b6 100644
--- a/src/corelib/tools/qcryptographichash.cpp
+++ b/src/corelib/tools/qcryptographichash.cpp
@@ -1331,15 +1331,30 @@ bool QMessageAuthenticationCode::addData(QIODevice *device)
     return d->messageHash.addData(device);
 }
 
+/*!
+    \since 6.6
+
+    Returns the final hash value.
+
+    Note that the returned view remains valid only as long as the
+    QMessageAuthenticationCode object is not modified by other means.
+
+    \sa result()
+*/
+QByteArrayView QMessageAuthenticationCode::resultView() const noexcept
+{
+    d->finalize();
+    return d->result.toByteArrayView();
+}
+
 /*!
     Returns the final authentication code.
 
-    \sa QByteArray::toHex()
+    \sa resultView(), QByteArray::toHex()
 */
 QByteArray QMessageAuthenticationCode::result() const
 {
-    d->finalize();
-    return d->result.toByteArrayView().toByteArray();
+    return resultView().toByteArray();
 }
 
 void QMessageAuthenticationCodePrivate::finalize()
diff --git a/src/corelib/tools/qmessageauthenticationcode.h b/src/corelib/tools/qmessageauthenticationcode.h
index 3951a6e5fa..a7fb13d201 100644
--- a/src/corelib/tools/qmessageauthenticationcode.h
+++ b/src/corelib/tools/qmessageauthenticationcode.h
@@ -28,6 +28,7 @@ public:
     void addData(const QByteArray &data);
     bool addData(QIODevice *device);
 
+    QByteArrayView resultView() const noexcept;
     QByteArray result() const;
 
     static QByteArray hash(const QByteArray &message, const QByteArray &key,
diff --git a/src/plugins/tls/openssl/qdtls_openssl.cpp b/src/plugins/tls/openssl/qdtls_openssl.cpp
index d34cfe7c64..78288d8dd1 100644
--- a/src/plugins/tls/openssl/qdtls_openssl.cpp
+++ b/src/plugins/tls/openssl/qdtls_openssl.cpp
@@ -182,7 +182,7 @@ extern "C" int q_generate_cookie_callback(SSL *ssl, unsigned char *dst,
 
     QMessageAuthenticationCode hmac(dtls->hashAlgorithm, dtls->secret);
     hmac.addData(peerData);
-    const QByteArray cookie = hmac.result();
+    const QByteArrayView cookie = hmac.resultView();
     Q_ASSERT(cookie.size() >= 0);
     // DTLS1_COOKIE_LENGTH is erroneously 256 bytes long, must be 255 - RFC 6347, 4.2.1.
     *cookieLength = qMin(DTLS1_COOKIE_LENGTH - 1, cookie.size());
diff --git a/tests/auto/corelib/tools/qmessageauthenticationcode/tst_qmessageauthenticationcode.cpp b/tests/auto/corelib/tools/qmessageauthenticationcode/tst_qmessageauthenticationcode.cpp
index 59fecc1b56..002f6f587a 100644
--- a/tests/auto/corelib/tools/qmessageauthenticationcode/tst_qmessageauthenticationcode.cpp
+++ b/tests/auto/corelib/tools/qmessageauthenticationcode/tst_qmessageauthenticationcode.cpp
@@ -148,11 +148,11 @@ void tst_QMessageAuthenticationCode::result()
     QMessageAuthenticationCode mac(algo);
     mac.setKey(key);
     mac.addData(message);
-    QByteArray result = mac.result();
+    QByteArrayView resultView = mac.resultView();
 
-    QCOMPARE(result, code);
+    QCOMPARE(resultView, code);
 
-    result = QMessageAuthenticationCode::hash(message, key, algo);
+    const auto result = QMessageAuthenticationCode::hash(message, key, algo);
     QCOMPARE(result, code);
 }
 
@@ -178,7 +178,7 @@ void tst_QMessageAuthenticationCode::result_incremental()
     mac.setKey(key);
     mac.addData(leftPart);
     mac.addData(rightPart);
-    QByteArray result = mac.result();
+    QByteArrayView result = mac.resultView();
 
     QCOMPARE(result, code);
 }
@@ -200,7 +200,7 @@ void tst_QMessageAuthenticationCode::addData_overloads()
         QMessageAuthenticationCode mac(algo);
         mac.setKey(key);
         mac.addData(message.constData(), message.size());
-        QByteArray result = mac.result();
+        QByteArrayView result = mac.resultView();
 
         QCOMPARE(result, code);
     }
@@ -212,7 +212,7 @@ void tst_QMessageAuthenticationCode::addData_overloads()
         QMessageAuthenticationCode mac(algo);
         mac.setKey(key);
         QVERIFY(mac.addData(&buffer));
-        QByteArray result = mac.result();
+        QByteArrayView result = mac.resultView();
         buffer.close();
 
         QCOMPARE(result, code);