wayland/toplevel_management: add ToplevelManager.activeToplevel

src/wayland/toplevel_management/qml.cpp

@@ -3,6 +3,7 @@
 #include <qobject.h>
 #include <qtmetamacros.h>
 
+#include "../../core/util.hpp"
 #include "../../core/model.hpp"
 #include "../../core/proxywindow.hpp"
 #include "../../core/qmlscreen.hpp"
@@ -132,22 +133,49 @@ ObjectModel<Toplevel>* ToplevelManager::toplevels() { return &this->mToplevels;
 
 void ToplevelManager::onToplevelReady(impl::ToplevelHandle* handle) {
 	auto* toplevel = new Toplevel(handle, this);
+
+	// clang-format off
 	QObject::connect(toplevel, &Toplevel::closed, this, &ToplevelManager::onToplevelClosed);
+	QObject::connect(toplevel, &Toplevel::activatedChanged, this, &ToplevelManager::onToplevelActiveChanged);
+	// clang-format on
+
+	if (toplevel->activated()) this->setActiveToplevel(toplevel);
 	this->mToplevels.insertObject(toplevel);
 }
 
+void ToplevelManager::onToplevelActiveChanged() {
+	auto* toplevel = qobject_cast<Toplevel*>(this->sender());
+	if (toplevel->activated()) this->setActiveToplevel(toplevel);
+}
+
 void ToplevelManager::onToplevelClosed() {
 	auto* toplevel = qobject_cast<Toplevel*>(this->sender());
+	if (toplevel == this->mActiveToplevel) this->setActiveToplevel(nullptr);
 	this->mToplevels.removeObject(toplevel);
 }
 
+DEFINE_MEMBER_GETSET(ToplevelManager, activeToplevel, setActiveToplevel);
+
 ToplevelManager* ToplevelManager::instance() {
 	static auto* instance = new ToplevelManager(); // NOLINT
 	return instance;
 }
 
+ToplevelManagerQml::ToplevelManagerQml(QObject* parent): QObject(parent) {
+	QObject::connect(
+	    ToplevelManager::instance(),
+	    &ToplevelManager::activeToplevelChanged,
+	    this,
+	    &ToplevelManagerQml::activeToplevelChanged
+	);
+}
+
 ObjectModel<Toplevel>* ToplevelManagerQml::toplevels() {
 	return ToplevelManager::instance()->toplevels();
 }
 
+Toplevel* ToplevelManagerQml::activeToplevel() {
+	return ToplevelManager::instance()->activeToplevel();
+}
+
 } // namespace qs::wayland::toplevel_management

src/wayland/toplevel_management/qml.hpp

@@ -7,6 +7,7 @@
 #include "../../core/model.hpp"
 #include "../../core/proxywindow.hpp"
 #include "../../core/qmlscreen.hpp"
+#include "../../core/util.hpp"
 
 namespace qs::wayland::toplevel_management {
 
@@ -111,14 +112,27 @@ public:
 
 	static ToplevelManager* instance();
 
+signals:
+	void activeToplevelChanged();
+
 private slots:
 	void onToplevelReady(impl::ToplevelHandle* handle);
+	void onToplevelActiveChanged();
 	void onToplevelClosed();
 
 private:
 	explicit ToplevelManager();
 
 	ObjectModel<Toplevel> mToplevels {this};
+	Toplevel* mActiveToplevel = nullptr;
+
+	DECLARE_PRIVATE_MEMBER(
+	    ToplevelManager,
+	    activeToplevel,
+	    setActiveToplevel,
+	    mActiveToplevel,
+	    activeToplevelChanged
+	);
 };
 
 ///! Exposes a list of Toplevels.
@@ -127,14 +141,24 @@ private:
 /// wayland protocol.
 class ToplevelManagerQml: public QObject {
 	Q_OBJECT;
+	/// All toplevel windows exposed by the compositor.
 	Q_PROPERTY(ObjectModel<Toplevel>* toplevels READ toplevels CONSTANT);
+	/// Active toplevel or null.
+	///
+	/// > [!INFO] If multiple are active, this will be the most recently activated one.
+	/// > Usually compositors will not report more than one toplevel as active at a time.
+	Q_PROPERTY(Toplevel* activeToplevel READ activeToplevel NOTIFY activeToplevelChanged);
 	QML_NAMED_ELEMENT(ToplevelManager);
 	QML_SINGLETON;
 
 public:
-	explicit ToplevelManagerQml(QObject* parent = nullptr): QObject(parent) {}
+	explicit ToplevelManagerQml(QObject* parent = nullptr);
 
 	[[nodiscard]] static ObjectModel<Toplevel>* toplevels();
+	[[nodiscard]] static Toplevel* activeToplevel();
+
+signals:
+	void activeToplevelChanged();
 };
 
 } // namespace qs::wayland::toplevel_management