Q{File,Font,Color,Message}DialogOptions are no value classes

These classes are only held in QSharedPointer, so optimize for that:

1. Disable default ctor, copy ctor and assignment operator,
   destructor and swap for public users.
2. Add create() to return an instance in a shared pointer.
3. Allocate public and private classes in one memory block,
   use QSharedPointer::create() to also add the QSharedPointer
   control block to the same memory allocation.

As a consequence, this reduces the creation of a Q*DialogOptions
into a shared pointer by two memory allocations.

Add a macro to enable atomic updates to QtQuick and other users
outside QtBase.

[ChangeLog][QtGui]
[QFileDialogOptions/QFontDialogOptions/QMessageDialogOptions/QColorDialogOptions]
This class no longer has value semantics, but needs to be held
in QSharedPointer (as it always was). To copy an instance, use
the clone() method.

Change-Id: I4c81220e0a8286a310df1c224a30eca34824c4e6
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>
Reviewed-by: Shawn Rutledge <shawn.rutledge@theqtcompany.com>

1 files changed, 67 insertions, 28 deletions

diff --git a/src/gui/kernel/qplatformdialoghelper.cpp b/src/gui/kernel/qplatformdialoghelper.cpp
index fe4d167078..c36186b815 100644
--- a/src/gui/kernel/qplatformdialoghelper.cpp
+++ b/src/gui/kernel/qplatformdialoghelper.cpp
@@ -156,23 +156,33 @@ public:
     QString windowTitle;
 };
 
-QFontDialogOptions::QFontDialogOptions() : d(new QFontDialogOptionsPrivate)
+QFontDialogOptions::QFontDialogOptions(QFontDialogOptionsPrivate *dd)
+    : d(dd)
 {
 }
 
-QFontDialogOptions::QFontDialogOptions(const QFontDialogOptions &rhs) : d(rhs.d)
+QFontDialogOptions::~QFontDialogOptions()
 {
 }
 
-QFontDialogOptions &QFontDialogOptions::operator=(const QFontDialogOptions &rhs)
+namespace {
+    struct FontDialogCombined : QFontDialogOptionsPrivate, QFontDialogOptions
+    {
+        FontDialogCombined() : QFontDialogOptionsPrivate(), QFontDialogOptions(this) {}
+        FontDialogCombined(const FontDialogCombined &other)
+            : QFontDialogOptionsPrivate(other), QFontDialogOptions(this) {}
+    };
+}
+
+// static
+QSharedPointer<QFontDialogOptions> QFontDialogOptions::create()
 {
-    if (this != &rhs)
-        d = rhs.d;
-    return *this;
+    return QSharedPointer<FontDialogCombined>::create();
 }
 
-QFontDialogOptions::~QFontDialogOptions()
+QSharedPointer<QFontDialogOptions> QFontDialogOptions::clone() const
 {
+    return QSharedPointer<FontDialogCombined>::create(*static_cast<const FontDialogCombined*>(this));
 }
 
 QString QFontDialogOptions::windowTitle() const
@@ -289,23 +299,33 @@ public:
     QString windowTitle;
 };
 
-QColorDialogOptions::QColorDialogOptions() : d(new QColorDialogOptionsPrivate)
+QColorDialogOptions::QColorDialogOptions(QColorDialogOptionsPrivate *dd)
+    : d(dd)
 {
 }
 
-QColorDialogOptions::QColorDialogOptions(const QColorDialogOptions &rhs) : d(rhs.d)
+QColorDialogOptions::~QColorDialogOptions()
 {
 }
 
-QColorDialogOptions &QColorDialogOptions::operator=(const QColorDialogOptions &rhs)
+namespace {
+    struct ColorDialogCombined : QColorDialogOptionsPrivate, QColorDialogOptions
+    {
+        ColorDialogCombined() : QColorDialogOptionsPrivate(), QColorDialogOptions(this) {}
+        ColorDialogCombined(const ColorDialogCombined &other)
+            : QColorDialogOptionsPrivate(other), QColorDialogOptions(this) {}
+    };
+}
+
+// static
+QSharedPointer<QColorDialogOptions> QColorDialogOptions::create()
 {
-    if (this != &rhs)
-        d = rhs.d;
-    return *this;
+    return QSharedPointer<ColorDialogCombined>::create();
 }
 
-QColorDialogOptions::~QColorDialogOptions()
+QSharedPointer<QColorDialogOptions> QColorDialogOptions::clone() const
 {
+    return QSharedPointer<ColorDialogCombined>::create(*static_cast<const ColorDialogCombined*>(this));
 }
 
 QString QColorDialogOptions::windowTitle() const
@@ -436,23 +456,32 @@ public:
     QStringList supportedSchemes;
 };
 
-QFileDialogOptions::QFileDialogOptions() : d(new QFileDialogOptionsPrivate)
+QFileDialogOptions::QFileDialogOptions(QFileDialogOptionsPrivate *dd)
+    : d(dd)
 {
 }
 
-QFileDialogOptions::QFileDialogOptions(const QFileDialogOptions &rhs) : d(rhs.d)
+QFileDialogOptions::~QFileDialogOptions()
 {
 }
 
-QFileDialogOptions &QFileDialogOptions::operator=(const QFileDialogOptions &rhs)
+namespace {
+    struct FileDialogCombined : QFileDialogOptionsPrivate, QFileDialogOptions
+    {
+        FileDialogCombined() : QFileDialogOptionsPrivate(), QFileDialogOptions(this) {}
+        FileDialogCombined(const FileDialogCombined &other) : QFileDialogOptionsPrivate(other), QFileDialogOptions(this) {}
+    };
+}
+
+// static
+QSharedPointer<QFileDialogOptions> QFileDialogOptions::create()
 {
-    if (this != &rhs)
-        d = rhs.d;
-    return *this;
+    return QSharedPointer<FileDialogCombined>::create();
 }
 
-QFileDialogOptions::~QFileDialogOptions()
+QSharedPointer<QFileDialogOptions> QFileDialogOptions::clone() const
 {
+    return QSharedPointer<FileDialogCombined>::create(*static_cast<const FileDialogCombined*>(this));
 }
 
 QString QFileDialogOptions::windowTitle() const
@@ -728,23 +757,33 @@ public:
     QPlatformDialogHelper::StandardButtons buttons;
 };
 
-QMessageDialogOptions::QMessageDialogOptions() : d(new QMessageDialogOptionsPrivate)
+QMessageDialogOptions::QMessageDialogOptions(QMessageDialogOptionsPrivate *dd)
+    : d(dd)
 {
 }
 
-QMessageDialogOptions::QMessageDialogOptions(const QMessageDialogOptions &rhs) : d(rhs.d)
+QMessageDialogOptions::~QMessageDialogOptions()
 {
 }
 
-QMessageDialogOptions &QMessageDialogOptions::operator=(const QMessageDialogOptions &rhs)
+namespace {
+    struct MessageDialogCombined : QMessageDialogOptionsPrivate, QMessageDialogOptions
+    {
+        MessageDialogCombined() : QMessageDialogOptionsPrivate(), QMessageDialogOptions(this) {}
+        MessageDialogCombined(const MessageDialogCombined &other)
+            : QMessageDialogOptionsPrivate(other), QMessageDialogOptions(this) {}
+    };
+}
+
+// static
+QSharedPointer<QMessageDialogOptions> QMessageDialogOptions::create()
 {
-    if (this != &rhs)
-        d = rhs.d;
-    return *this;
+    return QSharedPointer<MessageDialogCombined>::create();
 }
 
-QMessageDialogOptions::~QMessageDialogOptions()
+QSharedPointer<QMessageDialogOptions> QMessageDialogOptions::clone() const
 {
+    return QSharedPointer<MessageDialogCombined>::create(*static_cast<const MessageDialogCombined*>(this));
 }
 
 QString QMessageDialogOptions::windowTitle() const