Replace QString::utf16() with data() in memcpy() and QByteArray ctor

QString::utf16() needlessly detaches fromRawData() to ensure a
terminating NUL. Use data() where we don't require said NUL, taking
care not to call the mutable data() overload, which would detach,
too.

Task-number: QTBUG-98763
Change-Id: I7075a8f18ab1f82ebbcf8cfab1643e8ab7f38d51
Reviewed-by: Marc Mutz <marc.mutz@qt.io>

src/corelib/io/qprocess_win.cpp

@@ -471,14 +471,14 @@ static QByteArray qt_create_environment(const QProcessEnvironmentPrivate::Map &e
         envlist.resize(envlist.size() + tmpSize);
 
         tmpSize = it.key().length() * sizeof(wchar_t);
-        memcpy(envlist.data() + pos, it.key().utf16(), tmpSize);
+        memcpy(envlist.data() + pos, it.key().data(), tmpSize);
         pos += tmpSize;
 
         memcpy(envlist.data() + pos, &equal, sizeof(wchar_t));
         pos += sizeof(wchar_t);
 
         tmpSize = it.value().length() * sizeof(wchar_t);
-        memcpy(envlist.data() + pos, it.value().utf16(), tmpSize);
+        memcpy(envlist.data() + pos, it.value().data(), tmpSize);
         pos += tmpSize;
 
         memcpy(envlist.data() + pos, &nul, sizeof(wchar_t));

src/corelib/io/qsettings_win.cpp

@@ -672,8 +672,8 @@ void QWinSettingsPrivate::set(const QString &uKey, const QVariant &value)
             }
 
             if (type == REG_BINARY) {
-                QString s = variantToString(value);
+                const QString s = variantToString(value);
-                regValueBuff = QByteArray(reinterpret_cast<const char*>(s.utf16()), s.length() * 2);
+                regValueBuff = QByteArray(reinterpret_cast<const char *>(s.data()), s.length() * 2);
             } else {
                 QStringList::const_iterator it = l.constBegin();
                 for (; it != l.constEnd(); ++it) {

src/gui/text/windows/qwindowsfontdatabase.cpp

@@ -480,7 +480,7 @@ static QChar *createFontFile(const QString &faceName)
     if (!faceName.isEmpty()) {
         const int nameLength = qMin(faceName.length(), LF_FACESIZE - 1);
         faceNamePtr = new QChar[nameLength + 1];
-        memcpy(static_cast<void *>(faceNamePtr), faceName.utf16(), sizeof(wchar_t) * nameLength);
+        memcpy(static_cast<void *>(faceNamePtr), faceName.data(), sizeof(wchar_t) * nameLength);
         faceNamePtr[nameLength] = u'\0';
     }
     return faceNamePtr;
@@ -990,7 +990,7 @@ QStringList QWindowsFontDatabase::addApplicationFont(const QByteArray &fontData,
             HDC hdc = GetDC(0);
             LOGFONT lf;
             memset(&lf, 0, sizeof(LOGFONT));
-            memcpy(lf.lfFaceName, familyName.utf16(), sizeof(wchar_t) * qMin(LF_FACESIZE - 1, familyName.size()));
+            memcpy(lf.lfFaceName, familyName.data(), sizeof(wchar_t) * qMin(LF_FACESIZE - 1, familyName.size()));
             lf.lfCharSet = DEFAULT_CHARSET;
             const QFontValues &values = fontValues.at(j);
             lf.lfWeight = values.weight;
@@ -1164,7 +1164,7 @@ QFontEngine *QWindowsFontDatabase::createEngine(const QFontDef &request, const Q
         const QString nameSubstitute = QWindowsFontEngineDirectWrite::fontNameSubstitute(fam);
         if (nameSubstitute != fam) {
             const int nameSubstituteLength = qMin(nameSubstitute.length(), LF_FACESIZE - 1);
-            memcpy(lf.lfFaceName, nameSubstitute.utf16(), nameSubstituteLength * sizeof(wchar_t));
+            memcpy(lf.lfFaceName, nameSubstitute.data(), nameSubstituteLength * sizeof(wchar_t));
             lf.lfFaceName[nameSubstituteLength] = 0;
         }
 

src/plugins/platforms/direct2d/qwindowsdirect2dpaintengine.cpp

@@ -1039,7 +1039,7 @@ public:
         const QString nameSubstitute = QSettings(QLatin1String(keyC), QSettings::NativeFormat).value(familyName, familyName).toString();
         if (nameSubstitute != familyName) {
             const int nameSubstituteLength = qMin(nameSubstitute.length(), LF_FACESIZE - 1);
-            memcpy(lf.lfFaceName, nameSubstitute.utf16(), size_t(nameSubstituteLength) * sizeof(wchar_t));
+            memcpy(lf.lfFaceName, nameSubstitute.data(), size_t(nameSubstituteLength) * sizeof(wchar_t));
             lf.lfFaceName[nameSubstituteLength] = 0;
         }
 

src/plugins/platforms/windows/qwindowsmime.cpp

@@ -670,7 +670,7 @@ bool QWindowsMimeURI::convertFromMime(const FORMATETC &formatetc, const QMimeDat
             auto *f = reinterpret_cast<wchar_t *>(files);
             for (int i=0; i<fileNames.size(); i++) {
                 const auto l = size_t(fileNames.at(i).length());
-                memcpy(f, fileNames.at(i).utf16(), l * sizeof(ushort));
+                memcpy(f, fileNames.at(i).data(), l * sizeof(ushort));
                 f += l;
                 *f++ = 0;
             }
@@ -682,8 +682,8 @@ bool QWindowsMimeURI::convertFromMime(const FORMATETC &formatetc, const QMimeDat
             const auto urls = mimeData->urls();
             QByteArray result;
             if (!urls.isEmpty()) {
-                QString url = urls.at(0).toString();
+                const QString url = urls.at(0).toString();
-                result = QByteArray(reinterpret_cast<const char *>(url.utf16()),
+                result = QByteArray(reinterpret_cast<const char *>(url.data()),
                                     url.length() * int(sizeof(ushort)));
             }
             result.append('\0');

src/plugins/platforms/xcb/qxcbmime.cpp

@@ -113,7 +113,7 @@ bool QXcbMime::mimeDataForAtom(QXcbConnection *connection, xcb_atom_t a, QMimeDa
         if (atomName == QLatin1String("text/uri-list")
             && connection->atomName(a) == "text/x-moz-url") {
             const QString mozUri = QLatin1String(data->split('\n').constFirst()) + QLatin1Char('\n');
-            *data = QByteArray(reinterpret_cast<const char *>(mozUri.utf16()),
+            *data = QByteArray(reinterpret_cast<const char *>(mozUri.data()),
                                mozUri.length() * 2);
         } else if (atomName == QLatin1String("application/x-color"))
             *dataFormat = 16;

src/plugins/sqldrivers/db2/qsql_db2.cpp

@@ -808,11 +808,11 @@ bool QDB2Result::exec()
                 break; }
             case QMetaType::QString:
             {
-                QString str(values.at(i).toString());
+                const QString str(values.at(i).toString());
                 if (*ind != SQL_NULL_DATA)
                     *ind = str.length() * sizeof(QChar);
                 if (bindValueType(i) & QSql::Out) {
-                    QByteArray ba((char*)str.utf16(), str.capacity() * sizeof(QChar));
+                    QByteArray ba((char *)str.data(), str.capacity() * sizeof(QChar));
                     r = SQLBindParameter(d->hStmt,
                                         i + 1,
                                         qParamType[bindValueType(i) & 3],