Revert "xcb: implement missing bits from ICCCM 4.1.4 WM_STATE handling"

This reverts commit e946e6895a8517a887ac246905e0769edd766fcc.

It clears the duplicate show() and hide() too aggressive in
handleDeferredTasks() and can cause visible states out of sync between
qt and system(x11) when user switches visible on and off very
frequently.

This change also reverts 28138aa80a14279a72af2818f5bbbaa670283964.

Fixes: QTBUG-101347
Fixes: QTBUG-99810
Task-number: QTBUG-69515
Pick-to: 6.2 6.3 5.15
Change-Id: I419c324634be8ee6884e02032bb53a42738305ac
Reviewed-by: Liang Qi <liang.qi@qt.io>

2 files changed, 12 insertions, 119 deletions

diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index 464d032003..25a4bd5fa5 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -548,11 +548,6 @@ void QXcbWindow::setGeometry(const QRect &rect)
 {
     QPlatformWindow::setGeometry(rect);
 
-    if (shouldDeferTask(Task::SetGeometry)) {
-        m_deferredGeometry = rect;
-        return;
-    }
-
     propagateSizeHints();
 
     QXcbScreen *currentScreen = xcbScreen();
@@ -677,9 +672,6 @@ void QXcbWindow::setVisible(bool visible)
 
 void QXcbWindow::show()
 {
-    if (shouldDeferTask(Task::Map))
-        return;
-
     if (window()->isTopLevel()) {
 
         // update WM_NORMAL_HINTS
@@ -730,10 +722,6 @@ void QXcbWindow::show()
 
 void QXcbWindow::hide()
 {
-    if (shouldDeferTask(Task::Unmap))
-        return;
-
-    m_wmStateValid = false;
     xcb_unmap_window(xcb_connection(), m_window);
 
     // send synthetic UnmapNotify event according to icccm 4.1.4
@@ -893,9 +881,6 @@ QXcbWindow::NetWmStates QXcbWindow::netWmStates()
 
 void QXcbWindow::setWindowFlags(Qt::WindowFlags flags)
 {
-    if (shouldDeferTask(Task::SetWindowFlags))
-        return;
-
     Qt::WindowType type = static_cast<Qt::WindowType>(int(flags & Qt::WindowType_Mask));
 
     if (type == Qt::ToolTip)
@@ -925,8 +910,6 @@ void QXcbWindow::setWindowFlags(Qt::WindowFlags flags)
 
     setTransparentForMouseEvents(flags & Qt::WindowTransparentForInput);
     updateDoesNotAcceptFocus(flags & Qt::WindowDoesNotAcceptFocus);
-
-    m_isWmManagedWindow = !(flags & Qt::X11BypassWindowManagerHint);
 }
 
 void QXcbWindow::setMotifWmHints(Qt::WindowFlags flags)
@@ -1126,9 +1109,6 @@ void QXcbWindow::setWindowState(Qt::WindowStates state)
     if (state == m_windowState)
         return;
 
-    if (shouldDeferTask(Task::SetWindowState))
-        return;
-
     // unset old state
     if (m_windowState & Qt::WindowMinimized)
         xcb_map_window(xcb_connection(), m_window);
@@ -1846,10 +1826,6 @@ void QXcbWindow::handleUnmapNotifyEvent(const xcb_unmap_notify_event_t *event)
     if (event->window == m_window) {
         m_mapped = false;
         QWindowSystemInterface::handleExposeEvent(window(), QRegion());
-        if (!m_isWmManagedWindow || parent()) {
-            m_wmStateValid = true;
-            handleDeferredTasks();
-        }
     }
 }
 
@@ -2165,98 +2141,30 @@ void QXcbWindow::handleLeaveNotifyEvent(const xcb_leave_notify_event_t *event)
     handleLeaveNotifyEvent(event->root_x, event->root_y, event->mode, event->detail, event->time);
 }
 
-bool QXcbWindow::shouldDeferTask(Task task)
-{
-    if (m_wmStateValid)
-        return false;
-
-    m_deferredTasks.append(task);
-    return true;
-}
-
-void QXcbWindow::handleDeferredTasks()
-{
-    Q_ASSERT(m_wmStateValid == true);
-    if (m_deferredTasks.isEmpty())
-        return;
-
-    bool map = false;
-    bool unmap = false;
-
-    QVector<Task> tasks;
-    for (auto taskIt = m_deferredTasks.rbegin(); taskIt != m_deferredTasks.rend(); ++taskIt) {
-        if (!tasks.contains(*taskIt))
-            tasks.prepend(*taskIt);
-    }
-
-    for (Task task : tasks) {
-        switch (task) {
-        case Task::Map:
-            map = true;
-            unmap = false;
-            break;
-        case Task::Unmap:
-            unmap = true;
-            map = false;
-            break;
-        case Task::SetGeometry:
-            setGeometry(m_deferredGeometry);
-            break;
-        case Task::SetWindowFlags:
-            setWindowFlags(window()->flags());
-            break;
-        case Task::SetWindowState:
-            setWindowState(window()->windowState());
-            break;
-        }
-    }
-    m_deferredTasks.clear();
-
-    if (map) {
-        Q_ASSERT(unmap == false);
-        show();
-    }
-    if (unmap) {
-        Q_ASSERT(map == false);
-        hide();
-    }
-}
-
 void QXcbWindow::handlePropertyNotifyEvent(const xcb_property_notify_event_t *event)
 {
     connection()->setTime(event->time);
 
-    const bool wmStateChanged = event->atom == atom(QXcbAtom::WM_STATE);
-    const bool netWmStateChanged = event->atom == atom(QXcbAtom::_NET_WM_STATE);
-    if (netWmStateChanged || wmStateChanged) {
-        if (wmStateChanged && !m_wmStateValid && m_isWmManagedWindow) {
-            // ICCCM 4.1.4
-            // Clients that want to re-use a client window (e.g. by mapping it again)
-            // after withdrawing it must wait for the withdrawal to be complete before
-            // proceeding. The preferred method for doing this is for clients to wait for
-            // a window manager to update or remove the WM_STATE property.
-            m_wmStateValid = true;
-            handleDeferredTasks();
-        }
-        if (event->state == XCB_PROPERTY_DELETE)
+    const bool propertyDeleted = event->state == XCB_PROPERTY_DELETE;
+
+    if (event->atom == atom(QXcbAtom::_NET_WM_STATE) || event->atom == atom(QXcbAtom::WM_STATE)) {
+        if (propertyDeleted)
             return;
 
-        if (wmStateChanged) {
+        Qt::WindowStates newState = Qt::WindowNoState;
+
+        if (event->atom == atom(QXcbAtom::WM_STATE)) { // WM_STATE: Quick check for 'Minimize'.
             auto reply = Q_XCB_REPLY(xcb_get_property, xcb_connection(),
                                      0, m_window, atom(QXcbAtom::WM_STATE),
                                      XCB_ATOM_ANY, 0, 1024);
             if (reply && reply->format == 32 && reply->type == atom(QXcbAtom::WM_STATE)) {
-                auto data = static_cast<const quint32 *>(xcb_get_property_value(reply.get()));
-                if (reply->length != 0) {
-                    const bool changedToWithdrawn = data[0] == XCB_ICCCM_WM_STATE_WITHDRAWN;
-                    const bool changedToIconic = data[0] == XCB_ICCCM_WM_STATE_ICONIC;
-                    m_minimized = changedToIconic || (changedToWithdrawn && m_minimized);
-                }
+                const quint32 *data = (const quint32 *)xcb_get_property_value(reply.get());
+                if (reply->length != 0)
+                    m_minimized = (data[0] == XCB_ICCCM_WM_STATE_ICONIC
+                                   || (data[0] == XCB_ICCCM_WM_STATE_WITHDRAWN && m_minimized));
             }
         }
 
-        // _NET_WM_STATE handling
-        Qt::WindowStates newState = Qt::WindowNoState;
         const NetWmStates states = netWmStates();
         // _NET_WM_STATE_HIDDEN should be set by the Window Manager to indicate that a window would
         // not be visible on the screen if its desktop/viewport were active and its coordinates were
@@ -2278,6 +2186,7 @@ void QXcbWindow::handlePropertyNotifyEvent(const xcb_property_notify_event_t *ev
             if ((m_windowState & Qt::WindowMinimized) && connection()->mouseGrabber() == this)
                 connection()->setMouseGrabber(nullptr);
         }
+        return;
     } else if (event->atom == atom(QXcbAtom::_NET_FRAME_EXTENTS)) {
         m_dirtyFrameMargins = true;
     }
diff --git a/src/plugins/platforms/xcb/qxcbwindow.h b/src/plugins/platforms/xcb/qxcbwindow.h
index 01aabfc429..2c65296d90 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.h
+++ b/src/plugins/platforms/xcb/qxcbwindow.h
@@ -74,14 +74,6 @@ public:
 
     Q_DECLARE_FLAGS(NetWmStates, NetWmState)
 
-    enum Task {
-        Map,
-        Unmap,
-        SetGeometry,
-        SetWindowFlags,
-        SetWindowState
-    };
-
     QXcbWindow(QWindow *window);
     ~QXcbWindow();
 
@@ -151,9 +143,6 @@ public:
 
     QXcbWindow *toWindow() override;
 
-    bool shouldDeferTask(Task task);
-    void handleDeferredTasks();
-
     void handleMouseEvent(xcb_timestamp_t time, const QPoint &local, const QPoint &global,
                           Qt::KeyboardModifiers modifiers, QEvent::Type type, Qt::MouseEventSource source);
 
@@ -291,11 +280,6 @@ protected:
     int m_swapInterval = -1;
 
     qreal m_sizeHintsScaleFactor = 1.0;
-
-    bool m_wmStateValid = true;
-    QVector<Task> m_deferredTasks;
-    bool m_isWmManagedWindow = true;
-    QRect m_deferredGeometry;
 };
 
 class QXcbForeignWindow : public QXcbWindow