Make QStringLiteral and QByteArrayLiteral always return the real types

Up until now, the macros would return an internal type that contained
the pointer to the data. This breaks code that tried to use the macros
with operators, like QStringBuilder but also when writing:

     QStringList() << QStringLiteral("a") << QStringLiteral("b");

This change seems to work fine now and I can also verify that this
works:

     const auto str = QStringLiteral("Hello");

Even though it creates a QString, which is non-POD and non-constexpr.

Change-Id: Iaf82af9bea4245513a1128ea54f9d2d3d785fb09
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@nokia.com>

4 files changed, 15 insertions, 73 deletions

diff --git a/src/corelib/tools/qbytearray.h b/src/corelib/tools/qbytearray.h
index 45be63aa9b..0f5ebcfb18 100644
--- a/src/corelib/tools/qbytearray.h
+++ b/src/corelib/tools/qbytearray.h
@@ -169,13 +169,14 @@ struct QByteArrayDataPtr
 #if defined(Q_COMPILER_LAMBDA)
 
 #  define QByteArrayLiteral(str) \
-    ([]() -> QByteArrayDataPtr { \
+    ([]() -> QByteArray { \
         enum { Size = sizeof(str) - 1 }; \
         static const QStaticByteArrayData<Size> qbytearray_literal = { \
             Q_STATIC_BYTE_ARRAY_DATA_HEADER_INITIALIZER(Size), \
             str }; \
         QByteArrayDataPtr holder = { qbytearray_literal.data_ptr() }; \
-        return holder; \
+        const QByteArray ba(holder); \
+        return ba; \
     }()) \
     /**/
 
@@ -185,22 +186,22 @@ struct QByteArrayDataPtr
 // To do that, we need the __extension__ {( )} trick which only GCC supports
 
 #  define QByteArrayLiteral(str) \
-    __extension__ ({ \
+    QByteArray(__extension__ ({ \
         enum { Size = sizeof(str) - 1 }; \
         static const QStaticByteArrayData<Size> qbytearray_literal = { \
             Q_STATIC_BYTE_ARRAY_DATA_HEADER_INITIALIZER(Size), \
             str }; \
         QByteArrayDataPtr holder = { qbytearray_literal.data_ptr() }; \
         holder; \
-    }) \
+    })) \
     /**/
 
 #endif
 
 #ifndef QByteArrayLiteral
-// no lambdas, not GCC, use const char * instead
+// no lambdas, not GCC, just return a temporary QByteArray
 
-# define QByteArrayLiteral(str) (str)
+# define QByteArrayLiteral(str) QByteArray(str, sizeof(str) - 1)
 #endif
 
 class Q_CORE_EXPORT QByteArray
diff --git a/src/corelib/tools/qstring.h b/src/corelib/tools/qstring.h
index edb140b682..a96046d837 100644
--- a/src/corelib/tools/qstring.h
+++ b/src/corelib/tools/qstring.h
@@ -113,13 +113,14 @@ Q_STATIC_ASSERT_X(sizeof(qunicodechar) == 2,
 # if defined(Q_COMPILER_LAMBDA)
 
 #  define QStringLiteral(str) \
-    ([]() -> QStringDataPtr { \
+    ([]() -> QString { \
         enum { Size = sizeof(QT_UNICODE_LITERAL(str))/2 - 1 }; \
         static const QStaticStringData<Size> qstring_literal = { \
             Q_STATIC_STRING_DATA_HEADER_INITIALIZER(Size), \
             QT_UNICODE_LITERAL(str) }; \
         QStringDataPtr holder = { qstring_literal.data_ptr() }; \
-        return holder; \
+        const QString s(holder); \
+        return s; \
     }()) \
     /**/
 
@@ -129,14 +130,14 @@ Q_STATIC_ASSERT_X(sizeof(qunicodechar) == 2,
 // To do that, we need the __extension__ {( )} trick which only GCC supports
 
 #  define QStringLiteral(str) \
-    __extension__ ({ \
+    QString(__extension__ ({ \
         enum { Size = sizeof(QT_UNICODE_LITERAL(str))/2 - 1 }; \
         static const QStaticStringData<Size> qstring_literal = { \
             Q_STATIC_STRING_DATA_HEADER_INITIALIZER(Size), \
             QT_UNICODE_LITERAL(str) }; \
         QStringDataPtr holder = { qstring_literal.data_ptr() }; \
         holder; \
-    }) \
+    })) \
     /**/
 
 # endif
@@ -144,9 +145,10 @@ Q_STATIC_ASSERT_X(sizeof(qunicodechar) == 2,
 
 #ifndef QStringLiteral
 // no lambdas, not GCC, or GCC in C++98 mode with 4-byte wchar_t
-// fallback, uses QLatin1String as next best options
+// fallback, return a temporary QString
+// source code is assumed to be encoded in UTF-8
 
-# define QStringLiteral(str) QLatin1String(str)
+# define QStringLiteral(str) QString::fromUtf8(str, sizeof(str) - 1)
 #endif
 
 #define Q_STATIC_STRING_DATA_HEADER_INITIALIZER_WITH_OFFSET(size, offset) \
diff --git a/src/corelib/tools/qstringbuilder.h b/src/corelib/tools/qstringbuilder.h
index 9a1fd6949b..9b1cd1ee7e 100644
--- a/src/corelib/tools/qstringbuilder.h
+++ b/src/corelib/tools/qstringbuilder.h
@@ -253,19 +253,6 @@ template <> struct QConcatenable<QString> : private QAbstractConcatenable
     }
 };
 
-template <> struct QConcatenable<QStringDataPtr> : private QAbstractConcatenable
-{
-    typedef QStringDataPtr type;
-    typedef QString ConvertTo;
-    enum { ExactSize = true };
-    static int size(const type &a) { return a.ptr->size; }
-    static inline void appendTo(const type &a, QChar *&out)
-    {
-        memcpy(out, reinterpret_cast<const char*>(a.ptr->data()), sizeof(QChar) * a.ptr->size);
-        out += a.ptr->size;
-    }
-};
-
 template <> struct QConcatenable<QStringRef> : private QAbstractConcatenable
 {
     typedef QStringRef type;
@@ -358,24 +345,6 @@ template <> struct QConcatenable<QByteArray> : private QAbstractConcatenable
     }
 };
 
-template <> struct QConcatenable<QByteArrayDataPtr> : private QAbstractConcatenable
-{
-    typedef QByteArrayDataPtr type;
-    typedef QByteArray ConvertTo;
-    enum { ExactSize = false };
-    static int size(const type &ba) { return ba.ptr->size; }
-#ifndef QT_NO_CAST_FROM_ASCII
-    static inline QT_ASCII_CAST_WARN void appendTo(const type &a, QChar *&out)
-    {
-        QAbstractConcatenable::convertFromAscii(a.ptr->data(), a.ptr->size, out);
-    }
-#endif
-    static inline void appendTo(const type &ba, char *&out)
-    {
-        ::memcpy(out, ba.ptr->data(), ba.ptr->size);
-        out += ba.ptr->size;
-    }
-};
 
 template <typename A, typename B>
 struct QConcatenable< QStringBuilder<A, B> >
diff --git a/tests/auto/corelib/tools/qstringbuilder/qstringbuilder1/stringbuilder.cpp b/tests/auto/corelib/tools/qstringbuilder/qstringbuilder1/stringbuilder.cpp
index 862789cc73..556b9ac16a 100644
--- a/tests/auto/corelib/tools/qstringbuilder/qstringbuilder1/stringbuilder.cpp
+++ b/tests/auto/corelib/tools/qstringbuilder/qstringbuilder1/stringbuilder.cpp
@@ -107,21 +107,6 @@ void runScenario()
     QCOMPARE(r, r3);
 #endif
 
-    {
-        static const QStaticStringData<12> literalData = {
-                Q_STATIC_STRING_DATA_HEADER_INITIALIZER(12),
-                { 's', 'o', 'm', 'e', ' ', 'l', 'i', 't', 'e', 'r', 'a', 'l' }
-            };
-        static QStringDataPtr literal = { literalData.data_ptr() };
-
-        r = literal;
-        QCOMPARE(r, string);
-        r = r Q literal;
-        QCOMPARE(r, r2);
-        r = literal Q literal;
-        QCOMPARE(r, r2);
-    }
-
 #ifndef QT_NO_CAST_FROM_ASCII
     r = string P LITERAL;
     QCOMPARE(r, r2);
@@ -226,21 +211,6 @@ void runScenario()
         QCOMPARE(r, ba);
     }
 
-    {
-        static const QStaticByteArrayData<12> literalData = {
-                Q_STATIC_BYTE_ARRAY_DATA_HEADER_INITIALIZER(12),
-                { 's', 'o', 'm', 'e', ' ', 'l', 'i', 't', 'e', 'r', 'a', 'l' }
-            };
-        static QByteArrayDataPtr literal = { literalData.data_ptr() };
-
-        QByteArray ba = literal;
-        QCOMPARE(ba, QByteArray(LITERAL));
-        ba = ba Q literal;
-        QCOMPARE(ba, QByteArray(LITERAL LITERAL));
-        ba = literal Q literal;
-        QCOMPARE(ba, QByteArray(LITERAL LITERAL));
-    }
-
     //operator QString  +=
     {
         QString str = QString::fromUtf8(UTF8_LITERAL);