Respect roles of buttons added to QMessageBox

When a button added to QMessageBox has AcceptRole or YesRole, the signal
accepted() will be emitted upon click on the button. If the button has
RejectRole or NoRole, the signal rejected() will be emitted upon click
on the button. If a button has a different role, neither accepted() nor
rejected() will be emitted. This works for both standard and custom
buttons.
The signal finished() with result code will be sent regardless of a
clicked button role.
Also added documentation strings for some methods of private classes in
order to have better tooltips in IDE(s).

Task-number: QTBUG-44131
Change-Id: I521a4e5112eb4cf168f6fbb4c002dbe119aeeb09
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

3 files changed, 78 insertions, 15 deletions

diff --git a/src/widgets/dialogs/qdialog.cpp b/src/widgets/dialogs/qdialog.cpp
index 6f96018f3e..1fb5e61301 100644
--- a/src/widgets/dialogs/qdialog.cpp
+++ b/src/widgets/dialogs/qdialog.cpp
@@ -145,6 +145,41 @@ bool QDialogPrivate::canBeNativeDialog() const
     return false;
 }
 
+/*!
+    \internal
+
+    Properly hides dialog and sets the \p resultCode
+ */
+void QDialogPrivate::hide(int resultCode)
+{
+    Q_Q(QDialog);
+
+    q->setResult(resultCode);
+    q->hide();
+
+    close_helper(QWidgetPrivate::CloseNoEvent);
+    resetModalitySetByOpen();
+}
+
+/*!
+    \internal
+
+    Emits finished() signal with \p resultCode. If the \p dialogCode
+    is equal to 0 emits rejected(), if the \p dialogCode is equal to
+    1 emits accepted().
+ */
+void QDialogPrivate::finalize(int resultCode, int dialogCode)
+{
+    Q_Q(QDialog);
+
+    if (dialogCode == QDialog::Accepted)
+        emit q->accepted();
+    else if (dialogCode == QDialog::Rejected)
+        emit q->rejected();
+
+    emit q->finished(resultCode);
+}
+
 QWindow *QDialogPrivate::transientParentWindow() const
 {
     Q_Q(const QDialog);
@@ -593,17 +628,8 @@ int QDialog::exec()
 void QDialog::done(int r)
 {
     Q_D(QDialog);
-    setResult(r);
-    hide();
-
-    d->close_helper(QWidgetPrivate::CloseNoEvent);
-    d->resetModalitySetByOpen();
-
-    emit finished(r);
-    if (r == Accepted)
-        emit accepted();
-    else if (r == Rejected)
-        emit rejected();
+    d->hide(r);
+    d->finalize(r, r);
 }
 
 /*!
diff --git a/src/widgets/dialogs/qdialog_p.h b/src/widgets/dialogs/qdialog_p.h
index b1de56188c..92634f6793 100644
--- a/src/widgets/dialogs/qdialog_p.h
+++ b/src/widgets/dialogs/qdialog_p.h
@@ -122,6 +122,9 @@ public:
     QPlatformDialogHelper *platformHelper() const;
     virtual bool canBeNativeDialog() const;
 
+    void hide(int resultCode);
+    void finalize(int resultCode, int dialogCode);
+
 private:
     virtual void initHelper(QPlatformDialogHelper *) {}
     virtual void helperPrepareShow(QPlatformDialogHelper *) {}
diff --git a/src/widgets/dialogs/qmessagebox.cpp b/src/widgets/dialogs/qmessagebox.cpp
index ffbbe82856..ce918b8a74 100644
--- a/src/widgets/dialogs/qmessagebox.cpp
+++ b/src/widgets/dialogs/qmessagebox.cpp
@@ -209,6 +209,7 @@ public:
     void setupLayout();
     void _q_buttonClicked(QAbstractButton *);
     void _q_clicked(QPlatformDialogHelper::StandardButton button, QPlatformDialogHelper::ButtonRole role);
+    void setClickedButton(QAbstractButton *button);
 
     QAbstractButton *findButton(int button0, int button1, int button2, int flags);
     void addOldButtons(int button0, int button1, int button2);
@@ -216,6 +217,8 @@ public:
     QAbstractButton *abstractButtonForId(int id) const;
     int execReturnCode(QAbstractButton *button);
 
+    int dialogCodeForButton(QAbstractButton *button) const;
+
     void detectEscapeButton();
     void updateSize();
     int layoutMinimumWidth();
@@ -466,6 +469,27 @@ int QMessageBoxPrivate::execReturnCode(QAbstractButton *button)
     return ret;
 }
 
+/*!
+    \internal
+
+    Returns 0 for RejectedRole and NoRole, 1 for AcceptedRole and YesRole, -1 otherwise
+ */
+int QMessageBoxPrivate::dialogCodeForButton(QAbstractButton *button) const
+{
+    Q_Q(const QMessageBox);
+
+    switch (q->buttonRole(button)) {
+    case QMessageBox::AcceptRole:
+    case QMessageBox::YesRole:
+        return QDialog::Accepted;
+    case QMessageBox::RejectRole:
+    case QMessageBox::NoRole:
+        return QDialog::Rejected;
+    default:
+        return -1;
+    }
+}
+
 void QMessageBoxPrivate::_q_buttonClicked(QAbstractButton *button)
 {
     Q_Q(QMessageBox);
@@ -477,20 +501,30 @@ void QMessageBoxPrivate::_q_buttonClicked(QAbstractButton *button)
     } else
 #endif
     {
-        clickedButton = button;
-        q->done(execReturnCode(button)); // does not trigger closeEvent
-        emit q->buttonClicked(button);
+        setClickedButton(button);
 
         if (receiverToDisconnectOnClose) {
             QObject::disconnect(q, signalToDisconnectOnClose, receiverToDisconnectOnClose,
                                 memberToDisconnectOnClose);
-            receiverToDisconnectOnClose = 0;
+            receiverToDisconnectOnClose = nullptr;
         }
         signalToDisconnectOnClose.clear();
         memberToDisconnectOnClose.clear();
     }
 }
 
+void QMessageBoxPrivate::setClickedButton(QAbstractButton *button)
+{
+    Q_Q(QMessageBox);
+
+    clickedButton = button;
+    emit q->buttonClicked(clickedButton);
+
+    auto resultCode = execReturnCode(button);
+    hide(resultCode);
+    finalize(resultCode, dialogCodeForButton(button));
+}
+
 void QMessageBoxPrivate::_q_clicked(QPlatformDialogHelper::StandardButton button, QPlatformDialogHelper::ButtonRole role)
 {
     Q_Q(QMessageBox);