5 files changed, 171 insertions, 55 deletions
diff --git a/src/plugins/platforms/wasm/qwasmcompositor.cpp b/src/plugins/platforms/wasm/qwasmcompositor.cpp
index 56b0592d6b0..922e802732c 100644
--- a/src/plugins/platforms/wasm/qwasmcompositor.cpp
+++ b/src/plugins/platforms/wasm/qwasmcompositor.cpp
@@ -22,6 +22,16 @@ QWasmWindow *asWasmWindow(QWindow *window)
 {
     return static_cast<QWasmWindow*>(window->handle());
 }
+
+QWasmWindowStack::PositionPreference positionPreferenceFromWindowFlags(Qt::WindowFlags flags)
+{
+    if (flags.testFlag(Qt::WindowStaysOnTopHint))
+        return QWasmWindowStack::PositionPreference::StayOnTop;
+    if (flags.testFlag(Qt::WindowStaysOnBottomHint))
+        return QWasmWindowStack::PositionPreference::StayOnBottom;
+    return QWasmWindowStack::PositionPreference::Regular;
+}
+
 }  // namespace
 
 using namespace emscripten;
@@ -67,8 +77,11 @@ void QWasmCompositor::destroy()
 
 void QWasmCompositor::addWindow(QWasmWindow *window)
 {
-    m_windowStack.pushWindow(window);
-    m_windowStack.topWindow()->requestActivateWindow();
+    if (m_windowStack.empty())
+        window->window()->setFlag(Qt::WindowStaysOnBottomHint);
+    m_windowStack.pushWindow(window, positionPreferenceFromWindowFlags(window->window()->flags()));
+    window->requestActivateWindow();
+    setActive(window);
 
     updateEnabledState();
 }
@@ -77,12 +90,27 @@ void QWasmCompositor::removeWindow(QWasmWindow *window)
 {
     m_requestUpdateWindows.remove(window);
     m_windowStack.removeWindow(window);
-    if (m_windowStack.topWindow())
+    if (m_windowStack.topWindow()) {
         m_windowStack.topWindow()->requestActivateWindow();
+        setActive(m_windowStack.topWindow());
+    }
 
     updateEnabledState();
 }
 
+void QWasmCompositor::setActive(QWasmWindow *window)
+{
+    m_activeWindow = window;
+
+    auto it = m_windowStack.begin();
+    if (it == m_windowStack.end()) {
+        return;
+    }
+    for (; it != m_windowStack.end(); ++it) {
+        (*it)->onActivationChanged(*it == m_activeWindow);
+    }
+}
+
 void QWasmCompositor::updateEnabledState()
 {
     m_isEnabled = std::any_of(m_windowStack.begin(), m_windowStack.end(), [](QWasmWindow *window) {
@@ -100,6 +128,11 @@ void QWasmCompositor::lower(QWasmWindow *window)
     m_windowStack.lower(window);
 }
 
+void QWasmCompositor::windowPositionPreferenceChanged(QWasmWindow *window, Qt::WindowFlags flags)
+{
+    m_windowStack.windowPositionPreferenceChanged(window, positionPreferenceFromWindowFlags(flags));
+}
+
 QWindow *QWasmCompositor::windowAt(QPoint targetPointInScreenCoords, int padding) const
 {
     const auto found = std::find_if(
@@ -115,7 +148,7 @@ QWindow *QWasmCompositor::windowAt(QPoint targetPointInScreenCoords, int padding
 
 QWindow *QWasmCompositor::keyWindow() const
 {
-    return m_windowStack.topWindow() ? m_windowStack.topWindow()->window() : nullptr;
+    return m_activeWindow ? m_activeWindow->window() : nullptr;
 }
 
 void QWasmCompositor::requestUpdateAllWindows()
@@ -234,16 +267,6 @@ void QWasmCompositor::onTopWindowChanged()
     int z = zOrderForElementInFrontOfScreen;
     std::for_each(m_windowStack.rbegin(), m_windowStack.rend(),
                   [&z](QWasmWindow *window) { window->setZOrder(z++); });
-
-    auto it = m_windowStack.begin();
-    if (it == m_windowStack.end()) {
-        return;
-    }
-    (*it)->onActivationChanged(true);
-    ++it;
-    for (; it != m_windowStack.end(); ++it) {
-        (*it)->onActivationChanged(false);
-    }
 }
 
 QWasmScreen *QWasmCompositor::screen()
diff --git a/src/plugins/platforms/wasm/qwasmcompositor.h b/src/plugins/platforms/wasm/qwasmcompositor.h
index 5b8f22aaac3..617d14eecea 100644
--- a/src/plugins/platforms/wasm/qwasmcompositor.h
+++ b/src/plugins/platforms/wasm/qwasmcompositor.h
@@ -34,8 +34,10 @@ public:
     void removeWindow(QWasmWindow *window);
 
     void setVisible(QWasmWindow *window, bool visible);
+    void setActive(QWasmWindow *window);
     void raise(QWasmWindow *window);
     void lower(QWasmWindow *window);
+    void windowPositionPreferenceChanged(QWasmWindow *window, Qt::WindowFlags flags);
 
     void onScreenDeleting();
 
@@ -69,6 +71,7 @@ private:
     void updateEnabledState();
 
     QWasmWindowStack m_windowStack;
+    QWasmWindow *m_activeWindow = nullptr;
 
     bool m_isEnabled = true;
     QMap<QWasmWindow *, UpdateRequestDeliveryType> m_requestUpdateWindows;
diff --git a/src/plugins/platforms/wasm/qwasmwindow.cpp b/src/plugins/platforms/wasm/qwasmwindow.cpp
index 1bc09ee2704..bc6659c76ab 100644
--- a/src/plugins/platforms/wasm/qwasmwindow.cpp
+++ b/src/plugins/platforms/wasm/qwasmwindow.cpp
@@ -93,6 +93,7 @@ QWasmWindow::QWasmWindow(QWindow *w, QWasmDeadKeySupport *deadKeySupport,
     emscripten::val::module_property("specialHTMLTargets").set(canvasSelector(), m_canvas);
 
     m_compositor->addWindow(this);
+    m_flags = window()->flags();
 
     const auto pointerCallback = std::function([this](emscripten::val event) {
         if (processPointer(*PointerEvent::fromWeb(event)))
@@ -360,6 +361,8 @@ void QWasmWindow::onActivationChanged(bool active)
 
 void QWasmWindow::setWindowFlags(Qt::WindowFlags flags)
 {
+    if (flags.testFlag(Qt::WindowStaysOnTopHint) != m_flags.testFlag(Qt::WindowStaysOnTopHint))
+        m_compositor->windowPositionPreferenceChanged(this, flags);
     m_flags = flags;
     dom::syncCSSClassWith(m_qtWindow, "has-frame", hasFrame());
     dom::syncCSSClassWith(m_qtWindow, "has-shadow", !flags.testFlag(Qt::NoDropShadowWindowHint));
@@ -573,8 +576,10 @@ void QWasmWindow::requestActivateWindow()
         return;
     }
 
-    if (window()->isTopLevel())
+    if (window()->isTopLevel()) {
         raise();
+        m_compositor->setActive(this);
+    }
 
     if (!QWasmIntegration::get()->inputContext())
         m_canvas.call<void>("focus");
diff --git a/src/plugins/platforms/wasm/qwasmwindowstack.cpp b/src/plugins/platforms/wasm/qwasmwindowstack.cpp
index 098f1c1ff20..d3769c7a1bb 100644
--- a/src/plugins/platforms/wasm/qwasmwindowstack.cpp
+++ b/src/plugins/platforms/wasm/qwasmwindowstack.cpp
@@ -5,20 +5,38 @@
 
 QT_BEGIN_NAMESPACE
 
-QWasmWindowStack::QWasmWindowStack(TopWindowChangedCallbackType topWindowChangedCallback)
-    : m_topWindowChangedCallback(std::move(topWindowChangedCallback))
+QWasmWindowStack::QWasmWindowStack(WindowOrderChangedCallbackType windowOrderChangedCallback)
+    : m_windowOrderChangedCallback(std::move(windowOrderChangedCallback)),
+      m_regularWindowsBegin(m_windowStack.begin()),
+      m_alwaysOnTopWindowsBegin(m_windowStack.begin())
 {
 }
 
 QWasmWindowStack::~QWasmWindowStack() = default;
 
-void QWasmWindowStack::pushWindow(QWasmWindow *window)
+void QWasmWindowStack::pushWindow(QWasmWindow *window, PositionPreference position)
 {
     Q_ASSERT(m_windowStack.count(window) == 0);
 
-    m_windowStack.push_back(window);
-
-    m_topWindowChangedCallback();
+    if (position == PositionPreference::StayOnTop) {
+        const auto stayOnTopDistance =
+                std::distance(m_windowStack.begin(), m_alwaysOnTopWindowsBegin);
+        const auto regularDistance = std::distance(m_windowStack.begin(), m_regularWindowsBegin);
+        m_windowStack.push_back(window);
+        m_alwaysOnTopWindowsBegin = m_windowStack.begin() + stayOnTopDistance;
+        m_regularWindowsBegin = m_windowStack.begin() + regularDistance;
+    } else if (position == PositionPreference::Regular) {
+        const auto regularDistance = std::distance(m_windowStack.begin(), m_regularWindowsBegin);
+        m_alwaysOnTopWindowsBegin = m_windowStack.insert(m_alwaysOnTopWindowsBegin, window) + 1;
+        m_regularWindowsBegin = m_windowStack.begin() + regularDistance;
+    } else {
+        const auto stayOnTopDistance =
+                std::distance(m_windowStack.begin(), m_alwaysOnTopWindowsBegin);
+        m_regularWindowsBegin = m_windowStack.insert(m_regularWindowsBegin, window) + 1;
+        m_alwaysOnTopWindowsBegin = m_windowStack.begin() + stayOnTopDistance + 1;
+    }
+
+    m_windowOrderChangedCallback();
 }
 
 void QWasmWindowStack::removeWindow(QWasmWindow *window)
@@ -26,41 +44,105 @@ void QWasmWindowStack::removeWindow(QWasmWindow *window)
     Q_ASSERT(m_windowStack.count(window) == 1);
 
     auto it = std::find(m_windowStack.begin(), m_windowStack.end(), window);
-    const bool removingBottom = m_windowStack.begin() == it;
-    const bool removingTop = m_windowStack.end() - 1 == it;
-    if (removingBottom)
-        m_firstWindowTreatment = FirstWindowTreatment::Regular;
+    const auto position = getWindowPositionPreference(it);
+    const auto stayOnTopDistance = std::distance(m_windowStack.begin(), m_alwaysOnTopWindowsBegin);
+    const auto regularDistance = std::distance(m_windowStack.begin(), m_regularWindowsBegin);
 
     m_windowStack.erase(it);
 
-    if (removingTop)
-        m_topWindowChangedCallback();
+    m_alwaysOnTopWindowsBegin = m_windowStack.begin() + stayOnTopDistance
+            - (position != PositionPreference::StayOnTop ? 1 : 0);
+    m_regularWindowsBegin = m_windowStack.begin() + regularDistance
+            - (position == PositionPreference::StayOnBottom ? 1 : 0);
+
+    m_windowOrderChangedCallback();
 }
 
 void QWasmWindowStack::raise(QWasmWindow *window)
 {
     Q_ASSERT(m_windowStack.count(window) == 1);
 
-    if (window == rootWindow() || window == topWindow())
+    if (window == topWindow())
         return;
 
-    auto it = std::find(regularWindowsBegin(), m_windowStack.end(), window);
-    std::rotate(it, it + 1, m_windowStack.end());
-    m_topWindowChangedCallback();
+    auto it = std::find(m_windowStack.begin(), m_windowStack.end(), window);
+    auto itEnd = ([this, position = getWindowPositionPreference(it)]() {
+        switch (position) {
+        case PositionPreference::StayOnTop:
+            return m_windowStack.end();
+        case PositionPreference::Regular:
+            return m_alwaysOnTopWindowsBegin;
+        case PositionPreference::StayOnBottom:
+            return m_regularWindowsBegin;
+        }
+    })();
+    std::rotate(it, it + 1, itEnd);
+    m_windowOrderChangedCallback();
 }
 
 void QWasmWindowStack::lower(QWasmWindow *window)
 {
     Q_ASSERT(m_windowStack.count(window) == 1);
 
-    if (window == rootWindow())
+    if (window == *m_windowStack.begin())
         return;
 
-    const bool loweringTopWindow = topWindow() == window;
-    auto it = std::find(regularWindowsBegin(), m_windowStack.end(), window);
-    std::rotate(regularWindowsBegin(), it, it + 1);
-    if (loweringTopWindow && topWindow() != window)
-        m_topWindowChangedCallback();
+    auto it = std::find(m_windowStack.begin(), m_windowStack.end(), window);
+    auto itBegin = ([this, position = getWindowPositionPreference(it)]() {
+        switch (position) {
+        case PositionPreference::StayOnTop:
+            return m_alwaysOnTopWindowsBegin;
+        case PositionPreference::Regular:
+            return m_regularWindowsBegin;
+        case PositionPreference::StayOnBottom:
+            return m_windowStack.begin();
+        }
+    })();
+
+    std::rotate(itBegin, it, it + 1);
+    m_windowOrderChangedCallback();
+}
+
+void QWasmWindowStack::windowPositionPreferenceChanged(QWasmWindow *window,
+                                                       PositionPreference position)
+{
+    auto it = std::find(m_windowStack.begin(), m_windowStack.end(), window);
+    const auto currentPosition = getWindowPositionPreference(it);
+
+    const auto zones = static_cast<int>(position) - static_cast<int>(currentPosition);
+    Q_ASSERT(zones != 0);
+
+    if (zones < 0) {
+        // Perform right rotation so that the window lands on top of regular windows
+        const auto begin = std::make_reverse_iterator(it + 1);
+        const auto end = position == PositionPreference::Regular
+                ? std::make_reverse_iterator(m_alwaysOnTopWindowsBegin)
+                : std::make_reverse_iterator(m_regularWindowsBegin);
+        std::rotate(begin, begin + 1, end);
+        if (zones == -2) {
+            ++m_alwaysOnTopWindowsBegin;
+            ++m_regularWindowsBegin;
+        } else if (position == PositionPreference::Regular) {
+            ++m_alwaysOnTopWindowsBegin;
+        } else {
+            ++m_regularWindowsBegin;
+        }
+    } else {
+        // Perform left rotation so that the window lands at the bottom of always on top windows
+        const auto begin = it;
+        const auto end = position == PositionPreference::Regular ? m_regularWindowsBegin
+                                                                 : m_alwaysOnTopWindowsBegin;
+        std::rotate(begin, begin + 1, end);
+        if (zones == 2) {
+            --m_alwaysOnTopWindowsBegin;
+            --m_regularWindowsBegin;
+        } else if (position == PositionPreference::Regular) {
+            --m_regularWindowsBegin;
+        } else {
+            --m_alwaysOnTopWindowsBegin;
+        }
+    }
+    m_windowOrderChangedCallback();
 }
 
 QWasmWindowStack::iterator QWasmWindowStack::begin()
@@ -103,21 +185,19 @@ size_t QWasmWindowStack::size() const
     return m_windowStack.size();
 }
 
-QWasmWindow *QWasmWindowStack::rootWindow() const
-{
-    return m_firstWindowTreatment == FirstWindowTreatment::AlwaysAtBottom ? m_windowStack.first()
-                                                                          : nullptr;
-}
-
 QWasmWindow *QWasmWindowStack::topWindow() const
 {
     return m_windowStack.empty() ? nullptr : m_windowStack.last();
 }
 
-QWasmWindowStack::StorageType::iterator QWasmWindowStack::regularWindowsBegin()
+QWasmWindowStack::PositionPreference
+QWasmWindowStack::getWindowPositionPreference(StorageType::iterator windowIt) const
 {
-    return m_windowStack.begin()
-            + (m_firstWindowTreatment == FirstWindowTreatment::AlwaysAtBottom ? 1 : 0);
+    if (windowIt >= m_alwaysOnTopWindowsBegin)
+        return PositionPreference::StayOnTop;
+    if (windowIt >= m_regularWindowsBegin)
+        return PositionPreference::Regular;
+    return PositionPreference::StayOnBottom;
 }
 
 QT_END_NAMESPACE
diff --git a/src/plugins/platforms/wasm/qwasmwindowstack.h b/src/plugins/platforms/wasm/qwasmwindowstack.h
index 2eb48b08659..c75001157a0 100644
--- a/src/plugins/platforms/wasm/qwasmwindowstack.h
+++ b/src/plugins/platforms/wasm/qwasmwindowstack.h
@@ -24,7 +24,7 @@ class QWasmWindow;
 class Q_AUTOTEST_EXPORT QWasmWindowStack
 {
 public:
-    using TopWindowChangedCallbackType = std::function<void()>;
+    using WindowOrderChangedCallbackType = std::function<void()>;
 
     using StorageType = QList<QWasmWindow *>;
 
@@ -32,13 +32,20 @@ public:
     using const_iterator = StorageType::const_reverse_iterator;
     using const_reverse_iterator = StorageType::const_iterator;
 
-    explicit QWasmWindowStack(TopWindowChangedCallbackType topWindowChangedCallback);
+    enum class PositionPreference {
+        StayOnBottom,
+        Regular,
+        StayOnTop,
+    };
+
+    explicit QWasmWindowStack(WindowOrderChangedCallbackType topWindowChangedCallback);
     ~QWasmWindowStack();
 
-    void pushWindow(QWasmWindow *window);
+    void pushWindow(QWasmWindow *window, PositionPreference position);
     void removeWindow(QWasmWindow *window);
     void raise(QWasmWindow *window);
     void lower(QWasmWindow *window);
+    void windowPositionPreferenceChanged(QWasmWindow *window, PositionPreference position);
 
     // Iterates top-to-bottom
     iterator begin();
@@ -55,14 +62,12 @@ public:
     QWasmWindow *topWindow() const;
 
 private:
-    enum class FirstWindowTreatment { AlwaysAtBottom, Regular };
-
-    QWasmWindow *rootWindow() const;
-    StorageType::iterator regularWindowsBegin();
+    PositionPreference getWindowPositionPreference(StorageType::iterator windowIt) const;
 
-    TopWindowChangedCallbackType m_topWindowChangedCallback;
+    WindowOrderChangedCallbackType m_windowOrderChangedCallback;
     QList<QWasmWindow *> m_windowStack;
-    FirstWindowTreatment m_firstWindowTreatment = FirstWindowTreatment::AlwaysAtBottom;
+    StorageType::iterator m_regularWindowsBegin;
+    StorageType::iterator m_alwaysOnTopWindowsBegin;
 };
 
 QT_END_NAMESPACE