Add QTextStream operators for QStringView

Change-Id: I72d597fa21521a04b7f7c0e41bd45ee9dabb6222
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/serialization/qtextstream.cpp

@@ -2590,6 +2590,21 @@ QTextStream &QTextStream::operator<<(const QString &string)
     return *this;
 }
 
+/*!
+    \overload
+
+    Writes \a string to the stream, and returns a reference to the
+    QTextStream.
+    \since 5.12
+*/
+QTextStream &QTextStream::operator<<(QStringView string)
+{
+    Q_D(QTextStream);
+    CHECK_VALID_STREAM(*this);
+    d->putString(string.cbegin(), int(string.size()));
+    return *this;
+}
+
 /*!
     \overload
 

src/corelib/serialization/qtextstream.h

@@ -184,6 +184,7 @@ public:
     QTextStream &operator<<(float f);
     QTextStream &operator<<(double f);
     QTextStream &operator<<(const QString &s);
+    QTextStream &operator<<(QStringView s);
     QTextStream &operator<<(QLatin1String s);
     QTextStream &operator<<(const QStringRef &s);
     QTextStream &operator<<(const QByteArray &array);

tests/auto/corelib/serialization/qtextstream/tst_qtextstream.cpp

@@ -161,6 +161,7 @@ private slots:
     void string_write_operator_ToDevice();
     void latin1String_write_operator_ToDevice();
     void stringref_write_operator_ToDevice();
+    void stringview_write_operator_ToDevice();
 
     // other
     void skipWhiteSpace_data();
@@ -2573,6 +2574,17 @@ void tst_QTextStream::stringref_write_operator_ToDevice()
     QCOMPARE(buf.buffer().constData(), "No explicit lengthExplicit length");
 }
 
+void tst_QTextStream::stringview_write_operator_ToDevice()
+{
+    QBuffer buf;
+    buf.open(QBuffer::WriteOnly);
+    QTextStream stream(&buf);
+    const QStringView expected = QStringViewLiteral("expectedStringView");
+    stream << expected;
+    stream.flush();
+    QCOMPARE(buf.buffer().constData(), "expectedStringView");
+}
+
 // ------------------------------------------------------------------------------
 void tst_QTextStream::useCase1()
 {