Remove dead code & cull public API in WASM compositor

- Remove the manual destroy methods - destructor should handle
destruction
- Remove the unused enum QWasmStateFlag
- Make public API private where possible
- Adjust handleTouch->processTouch to keep consistency with other
process methods
- Remove dead fields in compositor
- Don't keep a dead screen entry in m_screens in qwasmintegration

Change-Id: I98caf4dbdda5ebd25c4a9c22a40140c7ed1d7aa7
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

src/plugins/platforms/wasm/qwasmcompositor.cpp

@@ -199,8 +199,6 @@ void QWasmCompositor::setVisible(QWasmWindow *window, bool visible)
         return;
 
     m_windowVisibility[window] = visible;
-    if (!visible)
-        m_globalDamage = window->window()->geometry(); // repaint previously covered area.
 
     requestUpdateWindow(window, QWasmCompositor::ExposeEventDelivery);
 }
@@ -212,15 +210,9 @@ void QWasmCompositor::raise(QWasmWindow *window)
 
 void QWasmCompositor::lower(QWasmWindow *window)
 {
-    m_globalDamage = window->window()->geometry(); // repaint previously covered area.
     m_windowStack.lower(window);
 }
 
-int QWasmCompositor::windowCount() const
-{
-    return m_windowStack.size();
-}
-
 QWindow *QWasmCompositor::windowAt(QPoint targetPointInScreenCoords, int padding) const
 {
     const auto found = std::find_if(
@@ -578,7 +570,7 @@ int QWasmCompositor::wheel_cb(int eventType, const EmscriptenWheelEvent *wheelEv
 int QWasmCompositor::touchCallback(int eventType, const EmscriptenTouchEvent *touchEvent, void *userData)
 {
     auto compositor = reinterpret_cast<QWasmCompositor*>(userData);
-    return static_cast<int>(compositor->handleTouch(eventType, touchEvent));
+    return static_cast<int>(compositor->processTouch(eventType, touchEvent));
 }
 
 bool QWasmCompositor::processPointer(const PointerEvent& event)
@@ -936,7 +928,7 @@ bool QWasmCompositor::processWheel(int eventType, const EmscriptenWheelEvent *wh
     return accepted;
 }
 
-int QWasmCompositor::handleTouch(int eventType, const EmscriptenTouchEvent *touchEvent)
+bool QWasmCompositor::processTouch(int eventType, const EmscriptenTouchEvent *touchEvent)
 {
     QList<QWindowSystemInterface::TouchPoint> touchPointList;
     touchPointList.reserve(touchEvent->numTouches);

src/plugins/platforms/wasm/qwasmcompositor.h

@@ -32,23 +32,14 @@ class QOpenGLContext;
 class QOpenGLTexture;
 class QWasmEventTranslator;
 
-class QWasmCompositor : public QObject
+class QWasmCompositor final : public QObject
 {
     Q_OBJECT
 public:
     QWasmCompositor(QWasmScreen *screen);
-    ~QWasmCompositor();
-    void initEventHandlers();
-    void deregisterEventHandlers();
-    void destroy();
+    ~QWasmCompositor() final;
 
-    enum QWasmStateFlag {
-        State_None =               0x00000000,
-        State_Enabled =            0x00000001,
-        State_Raised =             0x00000002,
-        State_Sunken =             0x00000004
-    };
-    Q_DECLARE_FLAGS(StateFlags, QWasmStateFlag)
+    void initEventHandlers();
 
     struct QWasmFrameOptions {
         QRect rect;
@@ -66,8 +57,6 @@ public:
     void raise(QWasmWindow *window);
     void lower(QWasmWindow *window);
 
-    int windowCount() const;
-
     QWindow *windowAt(QPoint globalPoint, int padding = 0) const;
     QWindow *keyWindow() const;
 
@@ -77,20 +66,11 @@ public:
     enum UpdateRequestDeliveryType { ExposeEventDelivery, UpdateRequestDelivery };
     void requestUpdateAllWindows();
     void requestUpdateWindow(QWasmWindow *window, UpdateRequestDeliveryType updateType = ExposeEventDelivery);
-    void requestUpdate();
-    void deliverUpdateRequests();
-    void deliverUpdateRequest(QWasmWindow *window, UpdateRequestDeliveryType updateType);
-    void handleBackingStoreFlush();
-    bool processKeyboard(int eventType, const EmscriptenKeyboardEvent *keyEvent);
-    bool processWheel(int eventType, const EmscriptenWheelEvent *wheelEvent);
-    int handleTouch(int eventType, const EmscriptenTouchEvent *touchEvent);
+
     void setCapture(QWasmWindow *window);
     void releaseCapture();
 
-    bool processMouseEnter(const EmscriptenMouseEvent *mouseEvent);
-    bool processMouseLeave();
-    void enterWindow(QWindow* window, const QPoint &localPoint, const QPoint &globalPoint);
-    void leaveWindow(QWindow* window);
+    void handleBackingStoreFlush();
 
 private slots:
     void frame();
@@ -146,6 +126,13 @@ private:
     };
 
     void onTopWindowChanged();
+    void deregisterEventHandlers();
+    void destroy();
+
+    void requestUpdate();
+    void deliverUpdateRequests();
+    void deliverUpdateRequest(QWasmWindow *window, UpdateRequestDeliveryType updateType);
+
     void drawWindow(QOpenGLTextureBlitter *blitter, QWasmScreen *screen, const QWasmWindow *window);
     void drawWindowContent(QOpenGLTextureBlitter *blitter, QWasmScreen *screen,
                            const QWasmWindow *window);
@@ -165,6 +152,15 @@ private:
 
     static int touchCallback(int eventType, const EmscriptenTouchEvent *ev, void *userData);
 
+    bool processKeyboard(int eventType, const EmscriptenKeyboardEvent *keyEvent);
+    bool processWheel(int eventType, const EmscriptenWheelEvent *wheelEvent);
+    bool processMouseEnter(const EmscriptenMouseEvent *mouseEvent);
+    bool processMouseLeave();
+    bool processTouch(int eventType, const EmscriptenTouchEvent *touchEvent);
+
+    void enterWindow(QWindow *window, const QPoint &localPoint, const QPoint &globalPoint);
+    void leaveWindow(QWindow *window);
+
     WindowManipulation m_windowManipulation;
     QWasmWasmWindowStack m_windowStack;
 
@@ -172,9 +168,6 @@ private:
     QScopedPointer<QOpenGLTextureBlitter> m_blitter;
 
     QHash<const QWasmWindow *, bool> m_windowVisibility;
-    QRegion m_globalDamage; // damage caused by expose, window close, etc.
-    bool m_needComposit = false;
-    bool m_inFlush = false;
     bool m_isEnabled = true;
     QSize m_targetSize;
     qreal m_targetDevicePixelRatio = 1;

src/plugins/platforms/wasm/qwasmintegration.cpp

@@ -311,6 +311,7 @@ void QWasmIntegration::removeScreen(const emscripten::val &element)
         return;
     }
     it->second->deleteScreen();
+    m_screens.erase(it);
 }
 
 void QWasmIntegration::resizeScreen(const emscripten::val &element)

src/plugins/platforms/wasm/qwasmscreen.cpp

@@ -100,10 +100,7 @@ QWasmScreen::QWasmScreen(const emscripten::val &containerOrCanvas)
 
 QWasmScreen::~QWasmScreen()
 {
-    // Delete the compositor before removing the screen from specialHTMLTargets,
-    // since its destructor needs to look up the target when deregistering
-    // event handlers.
-    m_compositor = nullptr;
+    Q_ASSERT(!m_compositor); // deleteScreen should have been called to remove this screen
 
     if (hasSpecialHtmlTargets())
         emscripten::val::module_property("specialHTMLTargets")
@@ -114,7 +111,10 @@ QWasmScreen::~QWasmScreen()
 
 void QWasmScreen::deleteScreen()
 {
-    m_compositor->destroy();
+    // Delete the compositor before removing the screen, since its destruction routine needs to use
+    // the fully operational screen.
+    m_compositor.reset();
+    // Deletes |this|!
     QWindowSystemInterface::handleScreenRemoved(this);
 }
 

src/plugins/platforms/wasm/qwasmwindow.cpp

@@ -156,7 +156,7 @@ void QWasmWindow::setGeometry(const QRect &rect)
     if (shouldInvalidate)
         invalidate();
     else
-        m_compositor->requestUpdate();
+        m_compositor->requestUpdateWindow(this);
 }
 
 void QWasmWindow::setVisible(bool visible)