From b53994de5f1b641ca2f6c79048339ff34fe14b55 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tor=20Arne=20Vestb=C3=B8?= <tor.arne.vestbo@qt.io>
Date: Wed, 29 May 2019 16:36:09 +0200
Subject: macOS: Use QMacNotificationObserver over manual notification handling

This also fixes a bug where we were implicitly capturing this inside
the block, which meant that we would crash if the theme was recreated.
The capture is now tied to the lifetime of QCocoaTheme.

Change-Id: I37df8e6c0b33bf41e76d66be3cf29576041a7546
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
---
 src/plugins/styles/mac/qmacstyle_mac.mm | 28 +++++++++++-----------------
 1 file changed, 11 insertions(+), 17 deletions(-)

(limited to 'src/plugins/styles')

diff --git a/src/plugins/styles/mac/qmacstyle_mac.mm b/src/plugins/styles/mac/qmacstyle_mac.mm
index ee5556ec9e..f88e3203bc 100644
--- a/src/plugins/styles/mac/qmacstyle_mac.mm
+++ b/src/plugins/styles/mac/qmacstyle_mac.mm
@@ -161,18 +161,6 @@ QT_NAMESPACE_ALIAS_OBJC_CLASS(NotificationReceiver);
     return self;
 }
 
-- (void)scrollBarStyleDidChange:(NSNotification *)notification
-{
-    Q_UNUSED(notification);
-
-    // purge destroyed scroll bars:
-    QMacStylePrivate::scrollBars.removeAll(QPointer<QObject>());
-
-    QEvent event(QEvent::StyleChange);
-    for (const auto &o : QMacStylePrivate::scrollBars)
-        QCoreApplication::sendEvent(o, &event);
-}
-
 - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object
         change:(NSDictionary<NSKeyValueChangeKey, id> *)change context:(void *)context
 {
@@ -2095,11 +2083,18 @@ QMacStyle::QMacStyle()
     Q_D(QMacStyle);
     QMacAutoReleasePool pool;
 
+    static QMacNotificationObserver scrollbarStyleObserver(nil,
+        NSPreferredScrollerStyleDidChangeNotification, []() {
+            // Purge destroyed scroll bars
+            QMacStylePrivate::scrollBars.removeAll(QPointer<QObject>());
+
+            QEvent event(QEvent::StyleChange);
+            for (const auto &o : QMacStylePrivate::scrollBars)
+                QCoreApplication::sendEvent(o, &event);
+    });
+
     d->receiver = [[NotificationReceiver alloc] initWithPrivateStyle:d];
-    [[NSNotificationCenter defaultCenter] addObserver:d->receiver
-                                             selector:@selector(scrollBarStyleDidChange:)
-                                                 name:NSPreferredScrollerStyleDidChangeNotification
-                                               object:nil];
+
 #if QT_MACOS_PLATFORM_SDK_EQUAL_OR_ABOVE(__MAC_10_14)
     if (QOperatingSystemVersion::current() >= QOperatingSystemVersion::MacOSMojave) {
         [NSApplication.sharedApplication addObserver:d->receiver forKeyPath:@"effectiveAppearance"
@@ -2113,7 +2108,6 @@ QMacStyle::~QMacStyle()
     Q_D(QMacStyle);
     QMacAutoReleasePool pool;
 
-    [[NSNotificationCenter defaultCenter] removeObserver:d->receiver];
 #if QT_MACOS_PLATFORM_SDK_EQUAL_OR_ABOVE(__MAC_10_14)
     if (QOperatingSystemVersion::current() >= QOperatingSystemVersion::MacOSMojave)
         [NSApplication.sharedApplication removeObserver:d->receiver forKeyPath:@"effectiveAppearance"];
-- 
cgit v1.2.3