Simplify Windows native event filter

There's no need for a global event filter as it checks for the window hwnd anyway. And, moreover, that creates problems as Qt filters some events to global event filters.

ui/platform/ui_platform_window.cpp

@@ -70,6 +70,13 @@ rpl::producer<HitTestResult> BasicWindowHelper::systemButtonDown() const {
 	return rpl::never<HitTestResult>();
 }
 
+bool BasicWindowHelper::nativeEvent(
+		const QByteArray &eventType,
+		void *message,
+		base::NativeEventResult *result) {
+	return false;
+}
+
 void BasicWindowHelper::setTitle(const QString &title) {
 	_window->setWindowTitle(title);
 }

ui/platform/ui_platform_window.h

@@ -8,6 +8,7 @@
 
 #include "base/flags.h"
 #include "base/object_ptr.h"
+#include "base/qt/qt_common_adapters.h"
 #include "ui/round_rect.h"
 
 namespace style {
@@ -48,6 +49,10 @@ public:
 		-> rpl::producer<HitTestResult>;
 	[[nodiscard]] virtual auto systemButtonDown() const
 		-> rpl::producer<HitTestResult>;
+	[[nodiscard]] virtual bool nativeEvent(
+		const QByteArray &eventType,
+		void *message,
+		base::NativeEventResult *result);
 	virtual void setTitle(const QString &title);
 	virtual void setTitleStyle(const style::WindowTitle &st);
 	virtual void setNativeFrame(bool enabled);

ui/platform/win/ui_window_win.cpp

@@ -18,7 +18,6 @@
 #include "styles/palette.h"
 #include "styles/style_widgets.h"
 
-#include <QtCore/QAbstractNativeEventFilter>
 #include <QtGui/QWindow>
 #include <QtWidgets/QStyleFactory>
 #include <QtWidgets/QApplication>
@@ -140,50 +139,6 @@ BOOL(__stdcall *AdjustWindowRectExForDpi)(
 
 } // namespace
 
-class WindowHelper::NativeFilter final : public QAbstractNativeEventFilter {
-public:
-	void registerWindow(HWND handle, not_null<WindowHelper*> helper);
-	void unregisterWindow(HWND handle);
-
-	bool nativeEventFilter(
-		const QByteArray &eventType,
-		void *message,
-		long *result) override;
-
-private:
-	base::flat_map<HWND, not_null<WindowHelper*>> _windowByHandle;
-
-};
-
-void WindowHelper::NativeFilter::registerWindow(
-		HWND handle,
-		not_null<WindowHelper*> helper) {
-	_windowByHandle.emplace(handle, helper);
-}
-
-void WindowHelper::NativeFilter::unregisterWindow(HWND handle) {
-	_windowByHandle.remove(handle);
-}
-
-bool WindowHelper::NativeFilter::nativeEventFilter(
-		const QByteArray &eventType,
-		void *message,
-		long *result) {
-	auto filtered = false;
-	const auto msg = static_cast<MSG*>(message);
-	const auto i = _windowByHandle.find(msg->hwnd);
-	if (i != end(_windowByHandle)) {
-		base::Integration::Instance().enterFromEventLoop([&] {
-			filtered = i->second->handleNativeEvent(
-				msg->message,
-				msg->wParam,
-				msg->lParam,
-				reinterpret_cast<LRESULT*>(result));
-		});
-	}
-	return filtered;
-}
-
 WindowHelper::WindowHelper(not_null<RpWidget*> window)
 : BasicWindowHelper(window)
 , _handle(GetWindowHandle(window))
@@ -196,7 +151,6 @@ WindowHelper::WindowHelper(not_null<RpWidget*> window)
 }
 
 WindowHelper::~WindowHelper() {
-	GetNativeFilter()->unregisterWindow(_handle);
 }
 
 void WindowHelper::initInWindow(not_null<RpWindow*> window) {
@@ -350,7 +304,6 @@ rpl::producer<HitTestResult> WindowHelper::systemButtonDown() const {
 
 void WindowHelper::init() {
 	_title->show();
-	GetNativeFilter()->registerWindow(_handle, this);
 
 	style::PaletteChanged(
 	) | rpl::start_with_next([=] {
@@ -479,6 +432,22 @@ void WindowHelper::init() {
 	updateCornersRounding();
 }
 
+bool WindowHelper::nativeEvent(
+		const QByteArray &eventType,
+		void *message,
+		base::NativeEventResult *result) {
+	const auto msg = static_cast<MSG*>(message);
+	auto lresult = LRESULT(*result);
+	const auto guard = gsl::finally([&] {
+		*result = base::NativeEventResult(lresult);
+	});
+	return handleNativeEvent(
+		msg->message,
+		msg->wParam,
+		msg->lParam,
+		&lresult);
+}
+
 bool WindowHelper::handleNativeEvent(
 		UINT msg,
 		WPARAM wParam,
@@ -882,18 +851,6 @@ void WindowHelper::updateFrameMargins() {
 	_frameMargins = QMargins(0, -r.top, 0, 0) / window()->devicePixelRatioF();
 }
 
-not_null<WindowHelper::NativeFilter*> WindowHelper::GetNativeFilter() {
-	Expects(QCoreApplication::instance() != nullptr);
-
-	static const auto GlobalFilter = [&] {
-		const auto application = QCoreApplication::instance();
-		const auto filter = Ui::CreateChild<NativeFilter>(application);
-		application->installNativeEventFilter(filter);
-		return filter;
-	}();
-	return GlobalFilter;
-}
-
 HWND GetWindowHandle(not_null<QWidget*> widget) {
 	const auto toplevel = widget->window();
 	toplevel->createWinId();

ui/platform/win/ui_window_win.h

@@ -44,10 +44,12 @@ public:
 	[[nodiscard]] auto systemButtonDown() const
 		-> rpl::producer<HitTestResult> override;
 
-private:
-	class NativeFilter;
-	friend class NativeFilter;
+	[[nodiscard]] bool nativeEvent(
+		const QByteArray &eventType,
+		void *message,
+		base::NativeEventResult *result) override;
 
+private:
 	void init();
 	void updateFrameMargins();
 	void updateWindowFrameColors();
@@ -70,7 +72,6 @@ private:
 	[[nodiscard]] HitTestResult systemButtonHitTest(int result) const;
 
 	[[nodiscard]] int titleHeight() const;
-	static not_null<NativeFilter*> GetNativeFilter();
 
 	const HWND _handle = nullptr;
 	const not_null<TitleWidget*> _title;

ui/widgets/rp_window.cpp

@@ -17,6 +17,8 @@ RpWindow::RpWindow(QWidget *parent)
 
 	_helper->initInWindow(this);
 	hide();
+
+	_initialized = true;
 }
 
 RpWindow::~RpWindow() = default;
@@ -99,4 +101,17 @@ void RpWindow::setBodyTitleArea(
 	_helper->setBodyTitleArea(std::move(testMethod));
 }
 
+bool RpWindow::nativeEvent(
+		const QByteArray &eventType,
+		void *message,
+		base::NativeEventResult *result) {
+	if (_initialized && _helper->nativeEvent(
+		eventType,
+		message,
+		result)) {
+		return true;
+	}
+	return RpWidget::nativeEvent(eventType, message, result);
+}
+
 } // namespace Ui

ui/widgets/rp_window.h

@@ -8,6 +8,7 @@
 
 #include "ui/rp_widget.h"
 #include "base/flags.h"
+#include "base/qt/qt_common_adapters.h"
 
 namespace style {
 struct WindowTitle;
@@ -67,7 +68,14 @@ public:
 	void close();
 	void setBodyTitleArea(Fn<WindowTitleHitTestFlags(QPoint)> testMethod);
 
+protected:
+	bool nativeEvent(
+		const QByteArray &eventType,
+		void *message,
+		base::NativeEventResult *result) override;
+
 private:
+	bool _initialized = false;
 	const std::unique_ptr<Platform::BasicWindowHelper> _helper;
 
 };