core/proxywindow: improve QsWindowAttached robustness

Can now track window parent window changes.
Added tests.

src/window/proxywindow.cpp

@@ -28,7 +28,6 @@ ProxyWindowBase::ProxyWindowBase(QObject* parent)
     , mContentItem(new QQuickItem()) {
 	QQmlEngine::setObjectOwnership(this->mContentItem, QQmlEngine::CppOwnership);
 	this->mContentItem->setParent(this);
-	this->mContentItem->setProperty("__qs_proxywindow", QVariant::fromValue(this));
 
 	// clang-format off
 	QObject::connect(this, &ProxyWindowBase::widthChanged, this, &ProxyWindowBase::onWidthChanged);
@@ -84,7 +83,7 @@ void ProxyWindowBase::onReload(QObject* oldInstance) {
 
 void ProxyWindowBase::postCompleteWindow() { this->setVisible(this->mVisible); }
 
-ProxiedWindow* ProxyWindowBase::createQQuickWindow() { return new ProxiedWindow(); }
+ProxiedWindow* ProxyWindowBase::createQQuickWindow() { return new ProxiedWindow(this); }
 
 void ProxyWindowBase::createWindow() {
 	if (this->window != nullptr) return;
@@ -375,9 +374,29 @@ QQmlListProperty<QObject> ProxyWindowBase::data() {
 void ProxyWindowBase::onWidthChanged() { this->mContentItem->setWidth(this->width()); }
 void ProxyWindowBase::onHeightChanged() { this->mContentItem->setHeight(this->height()); }
 
+ProxyWindowAttached::ProxyWindowAttached(QQuickItem* parent): QsWindowAttached(parent) {
+	this->updateWindow();
+}
+
 QObject* ProxyWindowAttached::window() const { return this->mWindow; }
 QQuickItem* ProxyWindowAttached::contentItem() const { return this->mWindow->contentItem(); }
 
+void ProxyWindowAttached::updateWindow() {
+	auto* window = static_cast<QQuickItem*>(this->parent())->window(); // NOLINT
+
+	if (auto* proxy = qobject_cast<ProxiedWindow*>(window)) {
+		this->setWindow(proxy->proxy());
+	} else {
+		this->setWindow(nullptr);
+	}
+}
+
+void ProxyWindowAttached::setWindow(ProxyWindowBase* window) {
+	if (window == this->mWindow) return;
+	this->mWindow = window;
+	emit this->windowChanged();
+}
+
 void ProxiedWindow::exposeEvent(QExposeEvent* event) {
 	this->QQuickWindow::exposeEvent(event);
 	emit this->exposed();

src/window/proxywindow.hpp

@@ -145,26 +145,36 @@ class ProxyWindowAttached: public QsWindowAttached {
 	Q_OBJECT;
 
 public:
-	explicit ProxyWindowAttached(ProxyWindowBase* window)
-	    : QsWindowAttached(window)
-	    , mWindow(window) {}
+	explicit ProxyWindowAttached(QQuickItem* parent);
 
 	[[nodiscard]] QObject* window() const override;
 	[[nodiscard]] QQuickItem* contentItem() const override;
 
+protected:
+	void updateWindow() override;
+
 private:
-	ProxyWindowBase* mWindow;
+	ProxyWindowBase* mWindow = nullptr;
+
+	void setWindow(ProxyWindowBase* window);
 };
 
 class ProxiedWindow: public QQuickWindow {
 	Q_OBJECT;
 
 public:
-	explicit ProxiedWindow(QWindow* parent = nullptr): QQuickWindow(parent) {}
+	explicit ProxiedWindow(ProxyWindowBase* proxy, QWindow* parent = nullptr)
+	    : QQuickWindow(parent)
+	    , mProxy(proxy) {}
+
+	[[nodiscard]] ProxyWindowBase* proxy() const { return this->mProxy; }
 
 signals:
 	void exposed();
 
 protected:
 	void exposeEvent(QExposeEvent* event) override;
+
+private:
+	ProxyWindowBase* mProxy;
 };

src/window/test/CMakeLists.txt

@@ -5,3 +5,4 @@ function (qs_test name)
 endfunction()
 
 qs_test(popupwindow popupwindow.cpp)
+qs_test(windowattached windowattached.cpp)

src/window/test/windowattached.cpp

@@ -0,0 +1,73 @@
+#include "windowattached.hpp"
+
+#include <qobject.h>
+#include <qquickitem.h>
+#include <qsignalspy.h>
+#include <qtest.h>
+#include <qtestcase.h>
+
+#include "../proxywindow.hpp"
+#include "../windowinterface.hpp"
+
+void TestWindowAttachment::attachedAfterReload() {
+	auto window = ProxyWindowBase();
+	auto item = QQuickItem();
+	item.setParentItem(window.contentItem());
+	window.reload(nullptr);
+
+	auto* attached = WindowInterface::qmlAttachedProperties(&item);
+	QCOMPARE_NE(attached, nullptr);
+	QCOMPARE(attached->window(), &window);
+}
+
+void TestWindowAttachment::attachedBeforeReload() {
+	auto window = ProxyWindowBase();
+	auto item = QQuickItem();
+	item.setParentItem(window.contentItem());
+
+	auto* attached = WindowInterface::qmlAttachedProperties(&item);
+	QCOMPARE_NE(attached, nullptr);
+	QCOMPARE(attached->window(), nullptr);
+
+	auto spy = QSignalSpy(attached, &QsWindowAttached::windowChanged);
+	window.reload(nullptr);
+
+	QCOMPARE(attached->window(), &window);
+	QCOMPARE(spy.length(), 1);
+}
+
+void TestWindowAttachment::owningWindowChanged() {
+	auto window1 = ProxyWindowBase();
+	auto window2 = ProxyWindowBase();
+	window1.reload(nullptr);
+	window2.reload(nullptr);
+
+	auto item = QQuickItem();
+	item.setParentItem(window1.contentItem());
+
+	auto* attached = WindowInterface::qmlAttachedProperties(&item);
+	QCOMPARE_NE(attached, nullptr);
+	QCOMPARE(attached->window(), &window1);
+
+	auto spy = QSignalSpy(attached, &QsWindowAttached::windowChanged);
+	item.setParentItem(window2.contentItem());
+	QCOMPARE(attached->window(), &window2);
+	// setParentItem changes the parent to nullptr before the new window.
+	QCOMPARE(spy.length(), 2);
+}
+
+void TestWindowAttachment::nonItemParents() {
+	auto window = ProxyWindowBase();
+
+	auto item = QQuickItem();
+	item.setParentItem(window.contentItem());
+	auto object = QObject(&item);
+
+	window.reload(nullptr);
+
+	auto* attached = WindowInterface::qmlAttachedProperties(&object);
+	QCOMPARE_NE(attached, nullptr);
+	QCOMPARE(attached->window(), &window);
+}
+
+QTEST_MAIN(TestWindowAttachment);

src/window/test/windowattached.hpp

@@ -0,0 +1,14 @@
+#pragma once
+
+#include <qobject.h>
+#include <qtmetamacros.h>
+
+class TestWindowAttachment: public QObject {
+	Q_OBJECT;
+
+private slots:
+	static void attachedAfterReload();
+	static void attachedBeforeReload();
+	static void owningWindowChanged();
+	static void nonItemParents();
+};

src/window/windowinterface.cpp

@@ -6,29 +6,16 @@
 
 #include "proxywindow.hpp"
 
+QsWindowAttached::QsWindowAttached(QQuickItem* parent): QObject(parent) {
+	QObject::connect(parent, &QQuickItem::windowChanged, this, &QsWindowAttached::updateWindow);
+}
+
 QsWindowAttached* WindowInterface::qmlAttachedProperties(QObject* object) {
-	auto* visualRoot = qobject_cast<QQuickItem*>(object);
-
-	ProxyWindowBase* proxy = nullptr;
-	while (visualRoot != nullptr) {
-		proxy = visualRoot->property("__qs_proxywindow").value<ProxyWindowBase*>();
-
-		if (proxy) break;
-		visualRoot = visualRoot->parentItem();
-	};
-
-	if (!proxy) return nullptr;
-
-	auto v = proxy->property("__qs_window_attached");
-	if (auto* attached = v.value<QsWindowAttached*>()) {
-		return attached;
+	while (object && !qobject_cast<QQuickItem*>(object)) {
+		object = object->parent();
 	}
 
-	auto* attached = new ProxyWindowAttached(proxy);
-
-	if (attached) {
-		proxy->setProperty("__qs_window_attached", QVariant::fromValue(attached));
-	}
-
-	return attached;
+	if (!object) return nullptr;
+	auto* item = static_cast<QQuickItem*>(object); // NOLINT
+	return new ProxyWindowAttached(item);
 }

src/window/windowinterface.hpp

@@ -142,14 +142,20 @@ signals:
 
 class QsWindowAttached: public QObject {
 	Q_OBJECT;
-	Q_PROPERTY(QObject* window READ window CONSTANT);
-	Q_PROPERTY(QQuickItem* contentItem READ contentItem CONSTANT);
+	Q_PROPERTY(QObject* window READ window NOTIFY windowChanged);
+	Q_PROPERTY(QQuickItem* contentItem READ contentItem NOTIFY windowChanged);
 	QML_ANONYMOUS;
 
 public:
 	[[nodiscard]] virtual QObject* window() const = 0;
 	[[nodiscard]] virtual QQuickItem* contentItem() const = 0;
 
+signals:
+	void windowChanged();
+
+protected slots:
+	virtual void updateWindow() = 0;
+
 protected:
-	explicit QsWindowAttached(QObject* parent): QObject(parent) {}
+	explicit QsWindowAttached(QQuickItem* parent);
 };