sqlbrowser example: use unique_ptr to hold m_ui

The old code used manual memory mangement (raw new/delete) to
(de)allocate the Ui struct. This is so 80s.

Use an owning smart pointer to manage the memory. Ordinarily, this
would have been QScopedPointer, but seeing as that doesn't have a
create() method to hide the raw new, use std::unique_ptr and
std::make_unique() instead.

Amends 2690822428deec4f0c08f4d118d69a7c6036369e.

Change-Id: Icabb9154eb38630855e14094b958af0214516f6b
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
(cherry picked from commit 0da2c2c4ef2219967db87021eece2a60b6e207af)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
(cherry picked from commit 88600c30964bc1d11ed09e3dddd4cbe4477f02d3)

examples/sql/sqlbrowser/browser.cpp

@@ -18,7 +18,7 @@
 
 Browser::Browser(QWidget *parent)
     : QWidget(parent)
-    , m_ui(new Ui::Browser)
+    , m_ui{std::make_unique<Ui::Browser>()}
 {
     m_ui->setupUi(this);
 
@@ -60,9 +60,7 @@ Browser::Browser(QWidget *parent)
 }
 
 Browser::~Browser()
-{
+    = default;
-    delete m_ui;
-}
 
 void Browser::exec()
 {

examples/sql/sqlbrowser/browser.h

@@ -7,6 +7,8 @@
 #include <QWidget>
 #include <QSqlTableModel>
 
+#include <memory>
+
 QT_FORWARD_DECLARE_CLASS(QSqlError)
 
 QT_BEGIN_NAMESPACE
@@ -50,7 +52,7 @@ signals:
     void statusMessage(const QString &message);
 
 private:
-    Ui::Browser *m_ui;
+    const std::unique_ptr<Ui::Browser> m_ui;
 };
 
 class CustomModel : public QSqlTableModel

examples/sql/sqlbrowser/qsqlconnectiondialog.cpp

@@ -11,7 +11,7 @@
 
 QSqlConnectionDialog::QSqlConnectionDialog(QWidget *parent)
     : QDialog(parent)
-    , m_ui(new Ui::QSqlConnectionDialogUi)
+    , m_ui{std::make_unique<Ui::QSqlConnectionDialogUi>()}
 {
     m_ui->setupUi(this);
 
@@ -24,9 +24,7 @@ QSqlConnectionDialog::QSqlConnectionDialog(QWidget *parent)
 }
 
 QSqlConnectionDialog::~QSqlConnectionDialog()
-{
+    = default;
-    delete m_ui;
-}
 
 QString QSqlConnectionDialog::driverName() const
 {

examples/sql/sqlbrowser/qsqlconnectiondialog.h

@@ -6,6 +6,8 @@
 
 #include <QDialog>
 
+#include <memory>
+
 QT_BEGIN_NAMESPACE
 namespace Ui
 {
@@ -31,7 +33,7 @@ public:
     void accept() override;
 
 private:
-    Ui::QSqlConnectionDialogUi *m_ui;
+    const std::unique_ptr<Ui::QSqlConnectionDialogUi> m_ui;
 };
 
 #endif