Android: replace QtAndroid::activity/service with QtAndroidPrivate

There's no need for both, and QtAndroidPrivate is a documented namespace.
Replace all calls to QtAndroid::activity/service with QtAndroidPrivate
equivalents, and drop the QtAndroid version. Since we no longer store a
global copy of the activity and service, we can drop the reference right
away.

This comes with a bit of overhead - QtAndroid::activity returned a copy
of a global static QJniObject (62cb5589b3723fe8162e190cd54d9c78929b98d2,
after which declared QtJniTypes became QJniObjects), while
QtAndroidPrivate::activity returns a newly created QtJniTypes::Activity
on each call.

This however makes it also safer, as the QJniObject is then associated
with the calling thread's JNI environment, and we can optimize critical
code paths where it's safe to do so later. Also, QtAndroid's activity
object was never updated, while QtAndroidPrivate's activity is updated
in the updateNativeActivity native method.

Change-Id: I36c5b504eac52d9e28b4c6b265daab8fedc877e2
Reviewed-by: Tinja Paavoseppä <tinja.paavoseppa@qt.io>
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>

src/corelib/kernel/qjnihelpers.cpp

@@ -253,12 +253,24 @@ jint QtAndroidPrivate::initJNI(JavaVM *vm, JNIEnv *env)
     return JNI_OK;
 }
 
+Q_CORE_EXPORT jobject qt_androidActivity()
+{
+    QReadLocker locker(g_updateMutex());
+    return g_jActivity;
+}
+
+
 QtJniTypes::Activity QtAndroidPrivate::activity()
 {
     QReadLocker locker(g_updateMutex());
     return g_jActivity;
 }
 
+Q_CORE_EXPORT jobject qt_androidService()
+{
+    return g_jService;
+}
+
 QtJniTypes::Service QtAndroidPrivate::service()
 {
     return g_jService;

src/plugins/platforms/android/androidjnimain.cpp

@@ -44,9 +44,7 @@ static jmethodID m_loadClassMethodID = nullptr;
 static AAssetManager *m_assetManager = nullptr;
 static jobject m_assets = nullptr;
 static jobject m_resourcesObj = nullptr;
-static QtJniTypes::Activity m_activityObject = nullptr;
 static jmethodID m_createSurfaceMethodID = nullptr;
-static QtJniTypes::Service m_serviceObject = nullptr;
 static jmethodID m_setSurfaceGeometryMethodID = nullptr;
 static jmethodID m_destroySurfaceMethodID = nullptr;
 
@@ -160,16 +158,6 @@ namespace QtAndroid
         return m_applicationClass;
     }
 
-    QtJniTypes::Activity activity()
-    {
-        return m_activityObject;
-    }
-
-    QtJniTypes::Service service()
-    {
-        return m_serviceObject;
-    }
-
     void setSystemUiVisibility(SystemUiVisibility uiVisibility)
     {
         QJniObject::callStaticMethod<void>(m_applicationClass, "setSystemUiVisibility", "(I)V", jint(uiVisibility));
@@ -496,7 +484,7 @@ static void waitForServiceSetup(JNIEnv *env, jclass /*clazz*/)
     Q_UNUSED(env);
     // The service must wait until the QCoreApplication starts otherwise onBind will be
     // called too early
-    if (m_serviceObject)
+    if (QtAndroidPrivate::service())
         QtAndroidPrivate::waitForServiceSetup();
 }
 
@@ -867,28 +855,24 @@ static int registerNatives(JNIEnv *env)
 
     jmethodID methodID;
     GET_AND_CHECK_STATIC_METHOD(methodID, m_applicationClass, "activity", "()Landroid/app/Activity;");
-    jobject activityObject = env->CallStaticObjectMethod(m_applicationClass, methodID);
+    jobject contextObject = env->CallStaticObjectMethod(m_applicationClass, methodID);
-    GET_AND_CHECK_STATIC_METHOD(methodID, m_applicationClass, "service", "()Landroid/app/Service;");
+    if (!contextObject) {
-    jobject serviceObject = env->CallStaticObjectMethod(m_applicationClass, methodID);
+        GET_AND_CHECK_STATIC_METHOD(methodID, m_applicationClass, "service", "()Landroid/app/Service;");
+        contextObject = env->CallStaticObjectMethod(m_applicationClass, methodID);
+    }
     GET_AND_CHECK_STATIC_METHOD(methodID, m_applicationClass, "classLoader", "()Ljava/lang/ClassLoader;");
     m_classLoaderObject = env->NewGlobalRef(env->CallStaticObjectMethod(m_applicationClass, methodID));
     clazz = env->GetObjectClass(m_classLoaderObject);
     GET_AND_CHECK_METHOD(m_loadClassMethodID, clazz, "loadClass", "(Ljava/lang/String;)Ljava/lang/Class;");
-    if (serviceObject)
-        m_serviceObject = serviceObject; // m_serviceObject creates and manages as global ref
 
-    if (activityObject)
+    if (contextObject) {
-        m_activityObject = activityObject; // m_activityObject creates and manages as global ref
-
-    jobject object = activityObject ? activityObject : serviceObject;
-    if (object) {
         FIND_AND_CHECK_CLASS("android/content/ContextWrapper");
         GET_AND_CHECK_METHOD(methodID, clazz, "getAssets", "()Landroid/content/res/AssetManager;");
-        m_assets = env->NewGlobalRef(env->CallObjectMethod(object, methodID));
+        m_assets = env->NewGlobalRef(env->CallObjectMethod(contextObject, methodID));
         m_assetManager = AAssetManager_fromJava(env, m_assets);
 
         GET_AND_CHECK_METHOD(methodID, clazz, "getResources", "()Landroid/content/res/Resources;");
-        m_resourcesObj = env->NewGlobalRef(env->CallObjectMethod(object, methodID));
+        m_resourcesObj = env->NewGlobalRef(env->CallObjectMethod(contextObject, methodID));
 
         FIND_AND_CHECK_CLASS("android/graphics/Bitmap");
         m_bitmapClass = static_cast<jclass>(env->NewGlobalRef(clazz));
@@ -907,6 +891,8 @@ static int registerNatives(JNIEnv *env)
                              m_bitmapDrawableClass,
                              "<init>",
                              "(Landroid/content/res/Resources;Landroid/graphics/Bitmap;)V");
+
+        env->DeleteLocalRef(contextObject);
     }
 
     return JNI_TRUE;

src/plugins/platforms/android/androidjnimain.h

@@ -50,8 +50,6 @@ namespace QtAndroid
     jobject assets();
     AAssetManager *assetManager();
     jclass applicationClass();
-    QtJniTypes::Activity activity();
-    QtJniTypes::Service service();
 
     // Keep synchronized with flags in ActivityDelegate.java
     enum SystemUiVisibility {

src/plugins/platforms/android/qandroidplatformdialoghelpers.cpp

@@ -19,7 +19,7 @@ static jclass g_messageDialogHelperClass = nullptr;
 
 QAndroidPlatformMessageDialogHelper::QAndroidPlatformMessageDialogHelper()
     : m_javaMessageDialog(g_messageDialogHelperClass, "(Landroid/app/Activity;)V",
-                          static_cast<jobject>(QtAndroid::activity()))
+                          static_cast<jobject>(QtAndroidPrivate::activity()))
 {
 }
 

src/plugins/platforms/android/qandroidplatformfiledialoghelper.cpp

@@ -25,7 +25,7 @@ const char JniIntentClass[] = "android/content/Intent";
 
 QAndroidPlatformFileDialogHelper::QAndroidPlatformFileDialogHelper()
     : QPlatformFileDialogHelper(),
-      m_activity(QtAndroid::activity())
+      m_activity(QtAndroidPrivate::activity())
 {
 }
 

src/plugins/platforms/android/qandroidplatformintegration.cpp

@@ -80,10 +80,14 @@ void *QAndroidPlatformNativeInterface::nativeResourceForIntegration(const QByteA
 {
     if (resource=="JavaVM")
         return QtAndroid::javaVM();
-    if (resource == "QtActivity")
+    if (resource == "QtActivity") {
-        return QtAndroid::activity();
+        extern Q_CORE_EXPORT jobject qt_androidActivity();
-    if (resource == "QtService")
+        return qt_androidActivity();
-        return QtAndroid::service();
+    }
+    if (resource == "QtService") {
+        extern Q_CORE_EXPORT jobject qt_androidService();
+        return qt_androidService();
+    }
     if (resource == "AndroidStyleData") {
         if (m_androidStyle) {
             if (m_androidStyle->m_styleData.isEmpty())
@@ -227,9 +231,9 @@ QAndroidPlatformIntegration::QAndroidPlatformIntegration(const QStringList &para
         m_accessibility = new QAndroidPlatformAccessibility();
 #endif // QT_CONFIG(accessibility)
 
-    QJniObject javaActivity(QtAndroid::activity());
+    QJniObject javaActivity = QtAndroidPrivate::activity();
     if (!javaActivity.isValid())
-        javaActivity = QtAndroid::service();
+        javaActivity = QtAndroidPrivate::service();
 
     if (javaActivity.isValid()) {
         QJniObject resources = javaActivity.callObjectMethod("getResources", "()Landroid/content/res/Resources;");
@@ -316,11 +320,11 @@ bool QAndroidPlatformIntegration::hasCapability(Capability cap) const
     switch (cap) {
         case ApplicationState: return true;
         case ThreadedPixmaps: return true;
-        case NativeWidgets: return QtAndroid::activity();
+        case NativeWidgets: return QtAndroidPrivate::activity();
-        case OpenGL: return QtAndroid::activity();
+        case OpenGL: return QtAndroidPrivate::activity();
-        case ForeignWindows: return QtAndroid::activity();
+        case ForeignWindows: return QtAndroidPrivate::activity();
-        case ThreadedOpenGL: return !needsBasicRenderloopWorkaround() && QtAndroid::activity();
+        case ThreadedOpenGL: return !needsBasicRenderloopWorkaround() && QtAndroidPrivate::activity();
-        case RasterGLSurface: return QtAndroid::activity();
+        case RasterGLSurface: return QtAndroidPrivate::activity();
         case TopStackedNativeChildWindows: return false;
         case MaximizeUsingFullscreenGeometry: return true;
         default:
@@ -330,7 +334,7 @@ bool QAndroidPlatformIntegration::hasCapability(Capability cap) const
 
 QPlatformBackingStore *QAndroidPlatformIntegration::createPlatformBackingStore(QWindow *window) const
 {
-    if (!QtAndroid::activity())
+    if (!QtAndroidPrivate::activity())
         return nullptr;
 
     return new QAndroidPlatformBackingStore(window);
@@ -338,7 +342,7 @@ QPlatformBackingStore *QAndroidPlatformIntegration::createPlatformBackingStore(Q
 
 QPlatformOpenGLContext *QAndroidPlatformIntegration::createPlatformOpenGLContext(QOpenGLContext *context) const
 {
-    if (!QtAndroid::activity())
+    if (!QtAndroidPrivate::activity())
         return nullptr;
     QSurfaceFormat format(context->format());
     format.setAlphaBufferSize(8);
@@ -356,7 +360,7 @@ QOpenGLContext *QAndroidPlatformIntegration::createOpenGLContext(EGLContext cont
 
 QPlatformOffscreenSurface *QAndroidPlatformIntegration::createPlatformOffscreenSurface(QOffscreenSurface *surface) const
 {
-    if (!QtAndroid::activity())
+    if (!QtAndroidPrivate::activity())
         return nullptr;
 
     QSurfaceFormat format(surface->requestedFormat());
@@ -370,7 +374,7 @@ QPlatformOffscreenSurface *QAndroidPlatformIntegration::createPlatformOffscreenS
 
 QOffscreenSurface *QAndroidPlatformIntegration::createOffscreenSurface(ANativeWindow *nativeSurface) const
 {
-    if (!QtAndroid::activity() || !nativeSurface)
+    if (!QtAndroidPrivate::activity() || !nativeSurface)
         return nullptr;
 
     auto *surface = new QOffscreenSurface;
@@ -381,7 +385,7 @@ QOffscreenSurface *QAndroidPlatformIntegration::createOffscreenSurface(ANativeWi
 
 QPlatformWindow *QAndroidPlatformIntegration::createPlatformWindow(QWindow *window) const
 {
-    if (!QtAndroid::activity())
+    if (!QtAndroidPrivate::activity())
         return nullptr;
 
 #if QT_CONFIG(vulkan)

src/plugins/platforms/android/qandroidplatformscreen.cpp

@@ -368,7 +368,7 @@ int QAndroidPlatformScreen::rasterSurfaces()
 void QAndroidPlatformScreen::doRedraw(QImage* screenGrabImage)
 {
     PROFILE_SCOPE;
-    if (!QtAndroid::activity())
+    if (!QtAndroidPrivate::activity())
         return;
 
     if (m_dirtyRect.isEmpty())

src/plugins/platforms/android/qandroidsystemlocale.cpp

@@ -21,11 +21,9 @@ void QAndroidSystemLocale::getLocaleFromJava() const
     QWriteLocker locker(&m_lock);
 
     QJniObject javaLocaleObject;
-    QJniObject javaActivity(QtAndroid::activity());
+    const QJniObject javaContext = QtAndroidPrivate::context();
-    if (!javaActivity.isValid())
+    if (javaContext.isValid()) {
-        javaActivity = QtAndroid::service();
+        QJniObject resources = javaContext.callObjectMethod("getResources", "()Landroid/content/res/Resources;");
-    if (javaActivity.isValid()) {
-        QJniObject resources = javaActivity.callObjectMethod("getResources", "()Landroid/content/res/Resources;");
         QJniObject configuration = resources.callObjectMethod("getConfiguration", "()Landroid/content/res/Configuration;");
 
         javaLocaleObject = configuration.getObjectField("locale", "Ljava/util/Locale;");