Inline the size and data pointer members in QString

I'd have preferred to use QArrayDataPointer<ushort> for QString, but
that option wasn't the best one. QArrayDataPointer try to do some
operations using QArrayDataOps and that would expand to unnecessary
code. What's more, the existing code expected to be able to modify and
access the d pointer.

Instead, this commit introduces QStringPrivate (named differently from
QStringData to catch potential users), which contains the three
members. This POD class is also used in QJsonValue to store the
"inlined" QString. QHashedString in qtdeclarative will need a similar
solution.

Change-Id: I33f072158e6e2cd031d4d2ffc81f4a8dbaf4e616
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 13 insertions, 31 deletions

diff --git a/src/corelib/text/qstringliteral.h b/src/corelib/text/qstringliteral.h
index a0d4ddc30b..a8cf8e2c64 100644
--- a/src/corelib/text/qstringliteral.h
+++ b/src/corelib/text/qstringliteral.h
@@ -49,8 +49,6 @@
 
 QT_BEGIN_NAMESPACE
 
-typedef QTypedArrayData<ushort> QStringData;
-
 // all our supported compilers support Unicode string literals,
 // even if their Q_COMPILER_UNICODE_STRING has been revoked due
 // to lacking stdlib support. But QStringLiteral only needs the
@@ -65,43 +63,27 @@ Q_STATIC_ASSERT_X(sizeof(qunicodechar) == 2,
 #define QStringLiteral(str) \
     ([]() noexcept -> 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() }; \
-        const QString qstring_literal_temp(holder); \
-        return qstring_literal_temp; \
+        static const QArrayData qstring_literal = { \
+            Q_BASIC_ATOMIC_INITIALIZER(-1), QArrayData::StaticDataFlags, Size, 0, sizeof(QArrayData) \
+        }; \
+        QStringPrivate holder = {  \
+            const_cast<QArrayData *>(&qstring_literal), \
+            reinterpret_cast<ushort *>(const_cast<qunicodechar *>(QT_UNICODE_LITERAL(str))), \
+            Size \
+        }; \
+        return QString(holder); \
     }()) \
     /**/
 
-#define Q_STATIC_STRING_DATA_HEADER_INITIALIZER_WITH_OFFSET(size, offset) \
-    { Q_BASIC_ATOMIC_INITIALIZER(-1), QArrayData::StaticDataFlags, size, 0, offset } \
-    /**/
-
-#define Q_STATIC_STRING_DATA_HEADER_INITIALIZER(size) \
-    Q_STATIC_STRING_DATA_HEADER_INITIALIZER_WITH_OFFSET(size, sizeof(QStringData)) \
-    /**/
-
 #if QT_DEPRECATED_SINCE(5, 14)
 # define QStringViewLiteral(str) QStringView(QT_UNICODE_LITERAL(str), QtPrivate::Deprecated)
 #endif
 
-template <int N>
-struct QStaticStringData
-{
-    QArrayData str;
-    qunicodechar data[N + 1];
-
-    QStringData *data_ptr() const
-    {
-        Q_ASSERT(str.isStatic());
-        return const_cast<QStringData *>(static_cast<const QStringData*>(&str));
-    }
-};
-
-struct QStringDataPtr
+struct QStringPrivate
 {
-    QStringData *ptr;
+    QArrayData *d;
+    ushort *b;
+    uint size;
 };
 
 QT_END_NAMESPACE