QCryptographicHash: extend hashInto to more than one piece of data

This allows use of the noexcept static function in cases where more
than one piece of data needs to be hashed, and concatenation of said
data would have to allocate memory.

Port QUuid to use the new function, allowing to mark the V3 and V5
create functions noexcept.

As a drive-by, take QUuid by value in the internal helper function,
fixing a Clazy warning.

Task-number: QTBUG-125431
Change-Id: I17938f0be44c91085e2aaa5574953f8dceacc990
Reviewed-by: Thiago Macieira <[email protected]>

4 files changed, 26 insertions, 13 deletions

diff --git a/src/corelib/plugin/quuid.cpp b/src/corelib/plugin/quuid.cpp
index 8c3b758aaca..99f8ee30b0d 100644
--- a/src/corelib/plugin/quuid.cpp
+++ b/src/corelib/plugin/quuid.cpp
@@ -116,12 +116,12 @@ static QUuid _q_uuidFromHex(const char *src)
     return QUuid();
 }
 
-static QUuid createFromName(const QUuid &ns, const QByteArray &baseData, QCryptographicHash::Algorithm algorithm, int version)
+static QUuid createFromName(QUuid ns, QByteArrayView baseData, QCryptographicHash::Algorithm algorithm, int version) noexcept
 {
-    QCryptographicHash hash(algorithm);
-    hash.addData(QByteArrayView{ns.toBytes()});
-    hash.addData(baseData);
-    QByteArrayView hashResult = hash.resultView();
+    std::byte buffer[20];
+    Q_ASSERT(sizeof buffer >= size_t(QCryptographicHash::hashLength(algorithm)));
+    QByteArrayView hashResult
+        = QCryptographicHash::hashInto(buffer, {QByteArrayView{ns.toBytes()}, baseData}, algorithm);
     Q_ASSERT(hashResult.size() >= 16);
     hashResult.truncate(16); // Sha1 will be too long
 
@@ -570,13 +570,13 @@ QUuid QUuid::fromString(QAnyStringView text) noexcept
   \sa variant(), version(), createUuidV3()
 */
 #ifndef QT_BOOTSTRAPPED
-QUuid QUuid::createUuidV3(const QUuid &ns, const QByteArray &baseData)
+QUuid QUuid::createUuidV3(const QUuid &ns, const QByteArray &baseData) noexcept
 {
     return createFromName(ns, baseData, QCryptographicHash::Md5, 3);
 }
 #endif
 
-QUuid QUuid::createUuidV5(const QUuid &ns, const QByteArray &baseData)
+QUuid QUuid::createUuidV5(const QUuid &ns, const QByteArray &baseData) noexcept
 {
     return createFromName(ns, baseData, QCryptographicHash::Sha1, 5);
 }
diff --git a/src/corelib/plugin/quuid.h b/src/corelib/plugin/quuid.h
index 14029f1abc9..580784723c7 100644
--- a/src/corelib/plugin/quuid.h
+++ b/src/corelib/plugin/quuid.h
@@ -221,9 +221,9 @@ public:
 public:
     static QUuid createUuid();
 #ifndef QT_BOOTSTRAPPED
-    static QUuid createUuidV3(const QUuid &ns, const QByteArray &baseData);
+    static QUuid createUuidV3(const QUuid &ns, const QByteArray &baseData) noexcept;
 #endif
-    static QUuid createUuidV5(const QUuid &ns, const QByteArray &baseData);
+    static QUuid createUuidV5(const QUuid &ns, const QByteArray &baseData) noexcept;
 #ifndef QT_BOOTSTRAPPED
     static inline QUuid createUuidV3(const QUuid &ns, const QString &baseData)
     {
diff --git a/src/corelib/tools/qcryptographichash.cpp b/src/corelib/tools/qcryptographichash.cpp
index 3807e32a723..f64f11ee44c 100644
--- a/src/corelib/tools/qcryptographichash.cpp
+++ b/src/corelib/tools/qcryptographichash.cpp
@@ -1166,22 +1166,29 @@ QByteArray QCryptographicHash::hash(QByteArrayView data, Algorithm method)
 
 /*!
     \since 6.8
+    \fn QCryptographicHash::hashInto(QSpan<char> buffer, QSpan<const QByteArrayView> data, Algorithm method);
+    \fn QCryptographicHash::hashInto(QSpan<uchar> buffer, QSpan<const QByteArrayView> data, Algorithm method);
+    \fn QCryptographicHash::hashInto(QSpan<std::byte> buffer, QSpan<const QByteArrayView> data, Algorithm method);
     \fn QCryptographicHash::hashInto(QSpan<char> buffer, QByteArrayView data, Algorithm method);
     \fn QCryptographicHash::hashInto(QSpan<uchar> buffer, QByteArrayView data, Algorithm method);
     \fn QCryptographicHash::hashInto(QSpan<std::byte> buffer, QByteArrayView data, Algorithm method);
 
     Returns the hash of \a data using \a method, using \a buffer to store the result.
 
+    If \a data is a span, adds all the byte array views to the hash, in the order given.
+
     The return value will be a sub-span of \a buffer, unless \a buffer is of
     insufficient size, in which case a null QByteArrayView is returned.
 
     \sa hash()
 */
-QByteArrayView QCryptographicHash::hashInto(QSpan<std::byte> buffer, QByteArrayView data,
+QByteArrayView QCryptographicHash::hashInto(QSpan<std::byte> buffer,
+                                            QSpan<const QByteArrayView> data,
                                             Algorithm method) noexcept
 {
     QCryptographicHashPrivate hash(method);
-    hash.addData(data);
+    for (QByteArrayView part : data)
+        hash.addData(part);
     hash.finalizeUnchecked(); // no mutex needed: no-one but us has access to 'hash'
     auto result = hash.resultView();
     if (buffer.size() < result.size())
diff --git a/src/corelib/tools/qcryptographichash.h b/src/corelib/tools/qcryptographichash.h
index 3d91c1f917c..8c4f70457f8 100644
--- a/src/corelib/tools/qcryptographichash.h
+++ b/src/corelib/tools/qcryptographichash.h
@@ -94,10 +94,16 @@ public:
     static QByteArray hash(QByteArrayView data, Algorithm method);
 
     static QByteArrayView hashInto(QSpan<char> buffer, QByteArrayView data, Algorithm method) noexcept
-    { return hashInto(as_writable_bytes(buffer), data, method); }
+    { return hashInto(as_writable_bytes(buffer), {&data, 1}, method); }
     static QByteArrayView hashInto(QSpan<uchar> buffer, QByteArrayView data, Algorithm method) noexcept
+    { return hashInto(as_writable_bytes(buffer), {&data, 1}, method); }
+    static QByteArrayView hashInto(QSpan<std::byte> buffer, QByteArrayView data, Algorithm method) noexcept
+    { return hashInto(buffer, {&data, 1}, method); }
+    static QByteArrayView hashInto(QSpan<char> buffer, QSpan<const QByteArrayView> data, Algorithm method) noexcept
+    { return hashInto(as_writable_bytes(buffer), data, method); }
+    static QByteArrayView hashInto(QSpan<uchar> buffer, QSpan<const QByteArrayView> data, Algorithm method) noexcept
     { return hashInto(as_writable_bytes(buffer), data, method); }
-    static QByteArrayView hashInto(QSpan<std::byte> buffer, QByteArrayView data, Algorithm method) noexcept;
+    static QByteArrayView hashInto(QSpan<std::byte> buffer, QSpan<const QByteArrayView> data, Algorithm method) noexcept;
 
     static int hashLength(Algorithm method);
     static bool supportsAlgorithm(Algorithm method);