Client: Check for shell integration when initializing platform plugin

This makes QWaylandDisplay::initialize return a boolean and moves the
QWaylandIntegration's failure check out of constructor as
QWaylandIntegration::shellIntegration is a virtual method, this also
removes the out-of-date comments about processEvents as it's no more
used in QWaylandDisplay::forceRoundTrip.

Fixes: QTBUG-102457
Pick-to: 6.5
Change-Id: I3c8f1d9fd195326b587b45318443c2beee1ebfc2
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: David Edmundson <davidedmundson@kde.org>

src/plugins/platforms/wayland/qwaylanddisplay.cpp

@@ -379,8 +379,11 @@ QWaylandDisplay::~QWaylandDisplay(void)
 
 // Steps which is called just after constructor. This separates registry_global() out of the constructor
 // so that factory functions in integration can be overridden.
-void QWaylandDisplay::initialize()
+bool QWaylandDisplay::initialize()
 {
+    if (!isInitialized())
+        return false;
+
     forceRoundTrip();
 
     if (!mWaitingScreens.isEmpty()) {
@@ -389,6 +392,8 @@ void QWaylandDisplay::initialize()
     }
     if (!mClientSideInputContextRequested)
         mTextInputManagerIndex = INT_MAX;
+
+    return qEnvironmentVariableIntValue("QT_WAYLAND_DONT_CHECK_SHELL_INTEGRATION") || shellIntegration();
 }
 
 void QWaylandDisplay::ensureScreen()

src/plugins/platforms/wayland/qwaylanddisplay_p.h

@@ -97,7 +97,7 @@ public:
     QWaylandDisplay(QWaylandIntegration *waylandIntegration);
     ~QWaylandDisplay(void) override;
 
-    void initialize();
+    bool initialize();
 
 #if QT_CONFIG(xkbcommon)
     struct xkb_context *xkbContext() const { return mXkbContext.get(); }

src/plugins/platforms/wayland/qwaylandintegration.cpp

@@ -83,10 +83,6 @@ QWaylandIntegration::QWaylandIntegration()
 #endif
 {
     mDisplay.reset(new QWaylandDisplay(this));
-    if (!mDisplay->isInitialized()) {
-        mFailed = true;
-        return;
-    }
 
     QWaylandWindow::fixedToplevelPositions =
             !qEnvironmentVariableIsSet("QT_WAYLAND_DISABLE_FIXED_POSITIONS");
@@ -99,6 +95,11 @@ QWaylandIntegration::~QWaylandIntegration()
     sInstance = nullptr;
 }
 
+bool QWaylandIntegration::init()
+{
+    return mDisplay->initialize();
+}
+
 QPlatformNativeInterface * QWaylandIntegration::nativeInterface() const
 {
     return mNativeInterface.data();
@@ -168,7 +169,7 @@ QPlatformNativeInterface *QWaylandIntegration::createPlatformNativeInterface()
 // Support platform specific initialization
 void QWaylandIntegration::initializePlatform()
 {
-    mDisplay->initialize();
+    mDisplay->initEventThread();
 
     mNativeInterface.reset(createPlatformNativeInterface());
     initializeInputDeviceIntegration();
@@ -184,14 +185,9 @@ void QWaylandIntegration::initializePlatform()
 
 void QWaylandIntegration::initialize()
 {
-    mDisplay->initEventThread();
-
-    // Call this after initializing event thread for QWaylandDisplay::forceRoundTrip()
     initializePlatform();
 
-    // But the aboutToBlock() and awake() should be connected after initializePlatform().
+    // Call this after initializing event thread for QWaylandDisplay::flushRequests()
-    // Otherwise the connected flushRequests() may consumes up all events before processEvents starts to wait,
-    // so that processEvents(QEventLoop::WaitForMoreEvents) may be blocked in the forceRoundTrip().
     QAbstractEventDispatcher *dispatcher = QGuiApplicationPrivate::eventDispatcher;
     QObject::connect(dispatcher, SIGNAL(aboutToBlock()), mDisplay.data(), SLOT(flushRequests()));
     QObject::connect(dispatcher, SIGNAL(awake()), mDisplay.data(), SLOT(flushRequests()));

src/plugins/platforms/wayland/qwaylandintegration_p.h

@@ -43,7 +43,7 @@ public:
 
     static QWaylandIntegration *instance() { return sInstance; }
 
-    bool hasFailed() { return mFailed; }
+    bool init();
 
     bool hasCapability(QPlatformIntegration::Capability cap) const override;
     QPlatformWindow *createPlatformWindow(QWindow *window) const override;
@@ -134,7 +134,6 @@ private:
 #if QT_CONFIG(accessibility)
     mutable QScopedPointer<QPlatformAccessibility> mAccessibility;
 #endif
-    bool mFailed = false;
     QMutex mClientBufferInitLock;
     bool mClientBufferIntegrationInitialized = false;
     bool mServerBufferIntegrationInitialized = false;

tests/auto/wayland/clientextension/tst_clientextension.cpp

@@ -123,5 +123,17 @@ void tst_clientextension::globalRemoved()
     QCOMPARE(spy.size(), 1);
 }
 
-QCOMPOSITOR_TEST_MAIN(tst_clientextension)
+int main(int argc, char **argv)
+{
+    QTemporaryDir tmpRuntimeDir;
+    setenv("XDG_RUNTIME_DIR", tmpRuntimeDir.path().toLocal8Bit(), 1);
+    setenv("QT_QPA_PLATFORM", "wayland", 1);
+    setenv("QT_WAYLAND_DONT_CHECK_SHELL_INTEGRATION", "1", 1);
+
+    tst_clientextension tc;
+    QGuiApplication app(argc, argv);
+    QTEST_SET_MAIN_SOURCE_PATH
+    return QTest::qExec(&tc, argc, argv);
+}
+
 #include "tst_clientextension.moc"