Teach QErrorMessage to use native dialog helper if available

And implement for macOS. The default modality of the QErrorMessage
on macOS now depends on whether the dialog has a parent or not.

The QErrorMessage must be hidden and re-shown again after each message,
so that the native dialog has a chance to recreate itself.

Change-Id: I474ed35d6271118834fac8e97f6f540a6fb89b8c
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

3 files changed, 17 insertions, 5 deletions

diff --git a/src/plugins/platforms/android/qandroidplatformdialoghelpers.cpp b/src/plugins/platforms/android/qandroidplatformdialoghelpers.cpp
index 97ae5064bd..05dd671122 100644
--- a/src/plugins/platforms/android/qandroidplatformdialoghelpers.cpp
+++ b/src/plugins/platforms/android/qandroidplatformdialoghelpers.cpp
@@ -54,6 +54,9 @@ bool QAndroidPlatformMessageDialogHelper::show(Qt::WindowFlags windowFlags,
     if (!opt.data())
         return false;
 
+    if (opt->supressionCheckBoxEnabled())
+        return false; // Can't support
+
     m_javaMessageDialog.callMethod<void>("setIcon", "(I)V", opt->icon());
 
     QString str = htmlText(opt->windowTitle());
diff --git a/src/plugins/platforms/cocoa/qcocoamessagedialog.mm b/src/plugins/platforms/cocoa/qcocoamessagedialog.mm
index 3d3970953d..84aea950c3 100644
--- a/src/plugins/platforms/cocoa/qcocoamessagedialog.mm
+++ b/src/plugins/platforms/cocoa/qcocoamessagedialog.mm
@@ -180,6 +180,8 @@ bool QCocoaMessageDialog::show(Qt::WindowFlags windowFlags, Qt::WindowModality w
             StandardButton::Ok, ButtonRole::AcceptRole);
     }
 
+    m_alert.showsSuppressionButton = options()->supressionCheckBoxEnabled();
+
     qCDebug(lcQpaDialogs) << "Showing" << m_alert;
 
     if (windowModality == Qt::WindowModal) {
@@ -230,6 +232,15 @@ void QCocoaMessageDialog::processResponse(NSModalResponse response)
 {
     qCDebug(lcQpaDialogs) << "Processing response" << response << "for" << m_alert;
 
+    // We can't re-use the same dialog for the next show() anyways,
+    // since the options may have changed, so get rid of it now,
+    // before we emit anything that might recurse back to hide/show/etc.
+    auto alert = std::exchange(m_alert, nil);
+    [alert autorelease];
+
+    if (alert.showsSuppressionButton)
+        emit supressionCheckBoxChanged(alert.suppressionButton.state == NSControlStateValueOn);
+
      if (response >= NSAlertFirstButtonReturn) {
         // Safe range for user-defined modal responses
         if (response == kModalResponseDialogHidden) {
@@ -270,11 +281,6 @@ void QCocoaMessageDialog::processResponse(NSModalResponse response)
 
     if (m_eventLoop)
         m_eventLoop->exit(response);
-
-    // We can't re-use the same dialog for the next show() anyways,
-    // since the options may have changed, so get rid of it now.
-    [m_alert release];
-    m_alert = nil;
 }
 
 void QCocoaMessageDialog::hide()
diff --git a/src/plugins/platforms/ios/qiosmessagedialog.mm b/src/plugins/platforms/ios/qiosmessagedialog.mm
index 1ac1bd0b97..1f39a94172 100644
--- a/src/plugins/platforms/ios/qiosmessagedialog.mm
+++ b/src/plugins/platforms/ios/qiosmessagedialog.mm
@@ -92,6 +92,9 @@ bool QIOSMessageDialog::show(Qt::WindowFlags windowFlags, Qt::WindowModality win
             || windowModality == Qt::NonModal) // We can only do modal dialogs
         return false;
 
+    if (options()->supressionCheckBoxEnabled())
+        return false; // Can't support
+
     m_alertController = [[UIAlertController
         alertControllerWithTitle:options()->windowTitle().toNSString()
         message:messageTextPlain().toNSString()