QMessageAuthenticationCode: Extract Methods finalize{,Unchecked}() from result()

This brings the code in line with its sibling code in
QCryptographicHash and prepares for a static hash() optimization and
the fixing of the result() re-entrancy issue (QTBUG-111347).

Task-number: QTBUG-111347
Pick-to: 6.5 6.4 6.2 5.15
Change-Id: I3d0c0cd2a37c2bbeb60974307ff138e26b82bf69
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

1 files changed, 20 insertions, 9 deletions

diff --git a/src/corelib/tools/qmessageauthenticationcode.cpp b/src/corelib/tools/qmessageauthenticationcode.cpp
index 4ff48fc822..8f131e45a0 100644
--- a/src/corelib/tools/qmessageauthenticationcode.cpp
+++ b/src/corelib/tools/qmessageauthenticationcode.cpp
@@ -75,6 +75,9 @@ public:
     bool messageHashInited;
 
     void initMessageHash();
+    void finalize();
+
+    void finalizeUnchecked();
 };
 
 void QMessageAuthenticationCodePrivate::initMessageHash()
@@ -208,27 +211,35 @@ bool QMessageAuthenticationCode::addData(QIODevice *device)
 */
 QByteArray QMessageAuthenticationCode::result() const
 {
-    if (!d->result.isEmpty())
-        return d->result;
+    d->finalize();
+    return d->result;
+}
 
-    d->initMessageHash();
+void QMessageAuthenticationCodePrivate::finalize()
+{
+    if (!result.isEmpty())
+        return;
+    initMessageHash();
+    finalizeUnchecked();
+}
 
-    const int blockSize = qt_hash_block_size(d->method);
+void QMessageAuthenticationCodePrivate::finalizeUnchecked()
+{
+    const int blockSize = qt_hash_block_size(method);
 
-    QByteArrayView hashedMessage = d->messageHash.resultView();
+    QByteArrayView hashedMessage = messageHash.resultView();
 
     QVarLengthArray<char> oKeyPad(blockSize);
-    const char * const keyData = d->key.constData();
+    const char * const keyData = key.constData();
 
     for (int i = 0; i < blockSize; ++i)
         oKeyPad[i] = keyData[i] ^ 0x5c;
 
-    QCryptographicHash hash(d->method);
+    QCryptographicHash hash(method);
     hash.addData(oKeyPad);
     hash.addData(hashedMessage);
 
-    d->result = hash.result();
-    return d->result;
+    result = hash.result();
 }
 
 /*!