Plumb QMessageBox::setCheckBox() through QPlatformMessageDialogHelper

Without this plumbing we have no way of knowing if the QMessageBox
has a checkbox set, and can't decide to skip the native dialog,
leaving the user without the expected checkbox.

As the suppression checkbox on macOS can be customized, we can use
this plumbing to actually provide native dialog support for generic
check boxes.

This mechanism can also be used by QErrorMessage, which now matches
behavior between native and non-native dialogs in terms of the label
of the checkbox and its initial state. We might want to tweak this
in the future, since user's might expect the suppression label and
state to match the system default, but that's something we can
expose from the platform theme if so, and should apply equally
to the non-native dialog.

Fixes: QTBUG-111803
Change-Id: Ied9fc34383fe79fbd8437592ad1c1993b9396178
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
(cherry picked from commit a0313c85a9b8ab6ba0ec273f0c8638e2f7b8cc18)
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

7 files changed, 62 insertions, 16 deletions

diff --git a/src/gui/kernel/qplatformdialoghelper.cpp b/src/gui/kernel/qplatformdialoghelper.cpp
index de0d4f43d7..c8510160f8 100644
--- a/src/gui/kernel/qplatformdialoghelper.cpp
+++ b/src/gui/kernel/qplatformdialoghelper.cpp
@@ -776,7 +776,8 @@ public:
     QList<QMessageDialogOptions::CustomButton> customButtons;
     int nextCustomButtonId;
     QPixmap iconPixmap;
-    bool enableSupressionCheckBox = false;
+    QString checkBoxLabel;
+    Qt::CheckState checkBoxState = Qt::Unchecked;
 };
 
 QMessageDialogOptions::QMessageDialogOptions(QMessageDialogOptionsPrivate *dd)
@@ -907,14 +908,20 @@ const QMessageDialogOptions::CustomButton *QMessageDialogOptions::customButton(i
     return (i < 0 ? nullptr : &d->customButtons.at(i));
 }
 
-void QMessageDialogOptions::setSupressionCheckBoxEnabled(bool enabled)
+void QMessageDialogOptions::setCheckBox(const QString &label, Qt::CheckState state)
 {
-    d->enableSupressionCheckBox = enabled;
+    d->checkBoxLabel = label;
+    d->checkBoxState = state;
 }
 
-bool QMessageDialogOptions::supressionCheckBoxEnabled() const
+QString QMessageDialogOptions::checkBoxLabel() const
 {
-    return d->enableSupressionCheckBox;
+    return d->checkBoxLabel;
+}
+
+Qt::CheckState QMessageDialogOptions::checkBoxState() const
+{
+    return d->checkBoxState;
 }
 
 QPlatformDialogHelper::ButtonRole QPlatformDialogHelper::buttonRole(QPlatformDialogHelper::StandardButton button)
diff --git a/src/gui/kernel/qplatformdialoghelper.h b/src/gui/kernel/qplatformdialoghelper.h
index b7aa02cc7c..fc2e85a8d6 100644
--- a/src/gui/kernel/qplatformdialoghelper.h
+++ b/src/gui/kernel/qplatformdialoghelper.h
@@ -451,8 +451,9 @@ public:
     const QList<CustomButton> &customButtons();
     const CustomButton *customButton(int id);
 
-    void setSupressionCheckBoxEnabled(bool enabled);
-    bool supressionCheckBoxEnabled() const;
+    void setCheckBox(const QString &label, Qt::CheckState state);
+    QString checkBoxLabel() const;
+    Qt::CheckState checkBoxState() const;
 
 private:
     QMessageDialogOptionsPrivate *d;
@@ -467,7 +468,7 @@ public:
 
 Q_SIGNALS:
     void clicked(QPlatformDialogHelper::StandardButton button, QPlatformDialogHelper::ButtonRole role);
-    void supressionCheckBoxChanged(bool checked);
+    void checkBoxStateChanged(Qt::CheckState state);
 
 private:
     QSharedPointer<QMessageDialogOptions> m_options;
diff --git a/src/plugins/platforms/android/qandroidplatformdialoghelpers.cpp b/src/plugins/platforms/android/qandroidplatformdialoghelpers.cpp
index 05dd671122..56b1ffd830 100644
--- a/src/plugins/platforms/android/qandroidplatformdialoghelpers.cpp
+++ b/src/plugins/platforms/android/qandroidplatformdialoghelpers.cpp
@@ -54,7 +54,7 @@ bool QAndroidPlatformMessageDialogHelper::show(Qt::WindowFlags windowFlags,
     if (!opt.data())
         return false;
 
-    if (opt->supressionCheckBoxEnabled())
+    if (!opt->checkBoxLabel().isNull())
         return false; // Can't support
 
     m_javaMessageDialog.callMethod<void>("setIcon", "(I)V", opt->icon());
diff --git a/src/plugins/platforms/cocoa/qcocoamessagedialog.mm b/src/plugins/platforms/cocoa/qcocoamessagedialog.mm
index 8ba204752b..e4e2260299 100644
--- a/src/plugins/platforms/cocoa/qcocoamessagedialog.mm
+++ b/src/plugins/platforms/cocoa/qcocoamessagedialog.mm
@@ -46,6 +46,16 @@ static QString toPlainText(const QString &text)
     return textDocument.toPlainText();
 }
 
+static NSControlStateValue controlStateFor(Qt::CheckState state)
+{
+    switch (state) {
+    case Qt::Checked: return NSControlStateValueOn;
+    case Qt::Unchecked: return NSControlStateValueOff;
+    case Qt::PartiallyChecked: return NSControlStateValueMixed;
+    }
+    Q_UNREACHABLE();
+}
+
 /*
     Called from QDialogPrivate::setNativeDialogVisible() when the message box
     is ready to be shown.
@@ -185,7 +195,14 @@ bool QCocoaMessageDialog::show(Qt::WindowFlags windowFlags, Qt::WindowModality w
             StandardButton::Ok, ButtonRole::AcceptRole);
     }
 
-    m_alert.showsSuppressionButton = options()->supressionCheckBoxEnabled();
+    if (auto checkBoxLabel = options()->checkBoxLabel(); !checkBoxLabel.isNull()) {
+        checkBoxLabel = QPlatformTheme::removeMnemonics(checkBoxLabel);
+        m_alert.suppressionButton.title = checkBoxLabel.toNSString();
+        auto state = options()->checkBoxState();
+        m_alert.suppressionButton.allowsMixedState = state == Qt::PartiallyChecked;
+        m_alert.suppressionButton.state = controlStateFor(state);
+        m_alert.showsSuppressionButton = YES;
+    }
 
     qCDebug(lcQpaDialogs) << "Showing" << m_alert;
 
@@ -233,6 +250,16 @@ void QCocoaMessageDialog::exec()
 // Custom modal response code to record that the dialog was hidden by us
 static const NSInteger kModalResponseDialogHidden = NSAlertThirdButtonReturn + 1;
 
+static Qt::CheckState checkStateFor(NSControlStateValue state)
+{
+    switch (state) {
+    case NSControlStateValueOn: return Qt::Checked;
+    case NSControlStateValueOff: return Qt::Unchecked;
+    case NSControlStateValueMixed: return Qt::PartiallyChecked;
+    }
+    Q_UNREACHABLE();
+}
+
 void QCocoaMessageDialog::processResponse(NSModalResponse response)
 {
     qCDebug(lcQpaDialogs) << "Processing response" << response << "for" << m_alert;
@@ -244,7 +271,7 @@ void QCocoaMessageDialog::processResponse(NSModalResponse response)
     [alert autorelease];
 
     if (alert.showsSuppressionButton)
-        emit supressionCheckBoxChanged(alert.suppressionButton.state == NSControlStateValueOn);
+        emit checkBoxStateChanged(checkStateFor(alert.suppressionButton.state));
 
      if (response >= NSAlertFirstButtonReturn) {
         // Safe range for user-defined modal responses
diff --git a/src/plugins/platforms/ios/qiosmessagedialog.mm b/src/plugins/platforms/ios/qiosmessagedialog.mm
index 1f39a94172..b95cfada60 100644
--- a/src/plugins/platforms/ios/qiosmessagedialog.mm
+++ b/src/plugins/platforms/ios/qiosmessagedialog.mm
@@ -92,7 +92,7 @@ bool QIOSMessageDialog::show(Qt::WindowFlags windowFlags, Qt::WindowModality win
             || windowModality == Qt::NonModal) // We can only do modal dialogs
         return false;
 
-    if (options()->supressionCheckBoxEnabled())
+    if (!options()->checkBoxLabel().isNull())
         return false; // Can't support
 
     m_alertController = [[UIAlertController
diff --git a/src/widgets/dialogs/qerrormessage.cpp b/src/widgets/dialogs/qerrormessage.cpp
index 29706c2ead..a00af9a8d1 100644
--- a/src/widgets/dialogs/qerrormessage.cpp
+++ b/src/widgets/dialogs/qerrormessage.cpp
@@ -63,9 +63,9 @@ void QErrorMessagePrivate::initHelper(QPlatformDialogHelper *helper)
 {
     Q_Q(QErrorMessage);
     auto *messageDialogHelper = static_cast<QPlatformMessageDialogHelper *>(helper);
-    QObject::connect(messageDialogHelper, &QPlatformMessageDialogHelper::supressionCheckBoxChanged, q,
-        [this](bool supressionChecked) {
-            again->setChecked(!supressionChecked);
+    QObject::connect(messageDialogHelper, &QPlatformMessageDialogHelper::checkBoxStateChanged, q,
+        [this](Qt::CheckState state) {
+            again->setCheckState(state);
         }
     );
     QObject::connect(messageDialogHelper, &QPlatformMessageDialogHelper::clicked, q,
@@ -86,7 +86,7 @@ void QErrorMessagePrivate::helperPrepareShow(QPlatformDialogHelper *helper)
     options->setText(QErrorMessage::tr("An error occurred"));
     options->setInformativeText(currentMessage);
     options->setIcon(QMessageDialogOptions::Critical);
-    options->setSupressionCheckBoxEnabled(true);
+    options->setCheckBox(again->text(), again->checkState());
     messageDialogHelper->setOptions(options);
 }
 
diff --git a/src/widgets/dialogs/qmessagebox.cpp b/src/widgets/dialogs/qmessagebox.cpp
index b695af0f3f..c11bd45815 100644
--- a/src/widgets/dialogs/qmessagebox.cpp
+++ b/src/widgets/dialogs/qmessagebox.cpp
@@ -2682,6 +2682,15 @@ void QMessageBoxPrivate::initHelper(QPlatformDialogHelper *h)
     Q_Q(QMessageBox);
     QObject::connect(h, SIGNAL(clicked(QPlatformDialogHelper::StandardButton,QPlatformDialogHelper::ButtonRole)),
                      q, SLOT(_q_clicked(QPlatformDialogHelper::StandardButton,QPlatformDialogHelper::ButtonRole)));
+
+    auto *messageDialogHelper = static_cast<QPlatformMessageDialogHelper *>(h);
+    QObject::connect(messageDialogHelper, &QPlatformMessageDialogHelper::checkBoxStateChanged, q,
+        [this](Qt::CheckState state) {
+            if (checkbox)
+                checkbox->setCheckState(state);
+        }
+    );
+
     static_cast<QPlatformMessageDialogHelper *>(h)->setOptions(options);
 }
 
@@ -2720,6 +2729,8 @@ void QMessageBoxPrivate::helperPrepareShow(QPlatformDialogHelper *)
     options->setIcon(helperIcon(q->icon()));
     options->setIconPixmap(q->iconPixmap());
     options->setStandardButtons(helperStandardButtons(q));
+    if (checkbox)
+        options->setCheckBox(checkbox->text(), checkbox->checkState());
 }
 
 void QMessageBoxPrivate::helperDone(QDialog::DialogCode code, QPlatformDialogHelper *)